This document provides the Indian Standard code of practice for using immersion vibrators to consolidate concrete. It discusses the proper use of immersion vibrators, including suitable concrete mixes, insertion depth and angle of the vibrator needle, thickness of concrete layers, and maintenance of the vibrators. It also addresses safety considerations for electrical vibrators and maintaining service logs to track vibrator performance and repairs. The standard is intended to guide obtaining maximum benefit from vibration consolidation of concrete.
This document provides specifications for concrete spreaders. It outlines various types of concrete spreaders, including reciprocating-blade, screw, and trough-hopper types. It specifies requirements for the size, construction, materials, and performance of concrete spreaders. The construction section describes requirements for the chassis, wheels, scrappers, and operator's station. Tolerances for adjustments to the operating width are also specified.
This document provides information on an Indian Standard for the design and construction of bored cast in-situ concrete piles. Some key points:
- It specifies requirements for bored cast in-situ concrete piles, which are formed by boring a hole in the ground and filling it with concrete.
- Pile capacity depends on skin friction along the shaft and end bearing at the tip. Design must ensure adequate factor of safety and allowable settlement.
- Site investigation data on soil properties, groundwater conditions, and structural loads is required for design.
- Equipment used can include percussion or rotary rigs for boring, and stabilization methods like circulation or suspended mud.
- Design considerations include adjacent structures
This document provides the summary of an Indian Standard code of practice for the design and construction of pile foundations. It specifically focuses on Section 2 which covers bored cast-in-situ concrete piles. Key points include:
1) It establishes terminology for bored cast-in-situ piles which are formed by excavating a hole in the ground and filling it with concrete, with or without a temporary casing.
2) It provides scope and covers the design and construction of bored concrete piles up to 2,500mm in diameter that transmit structural loads through end-bearing and/or shaft friction.
3) The standard references other related Indian Standards and international codes that were consulted in developing this practice.
The document describes Indian Standard code IS:2911 (Part I/Sec I) - 1979 which provides guidelines for the design and construction of driven cast in-situ concrete pile foundations. It covers necessary considerations for pile type, size, installation depth, load testing, and other factors based on site conditions and project requirements. Subsurface investigation data on soil properties, groundwater levels, and chemical testing is required to properly design and install pile foundations. The standard has been revised to incorporate recent developments and separate pile foundation types into distinct sections for ease of use.
This document provides the standard test method for evaluating the performance of screed board concrete vibrators by measuring their ability to compact concrete. The test involves vibrating a 180mm thick concrete slab with a vibrator and taking density measurements from cores cut from the slab. If the density from each core is at least 93% of the maximum theoretical density, the vibrator passes the test. This direct measurement of compaction achieved provides a better assessment of a vibrator's quality than indirect measurements of vibration characteristics alone.
This document provides information on Indian Standard IS:2911 regarding the design and construction of pile foundations. It outlines the necessary members of the committee working on revising the standard. The standard covers driven precast concrete piles, providing guidance on pile design, construction methods, site investigation needs, and other relevant details. It aims to incorporate recent developments in pile foundation engineering practices in India.
This document provides guidelines for designing foundations for rotary machines of low frequency (below 1,500 rpm), such as crushers, pumps, motor generators, compressors, and rolling mill stands. It discusses typical foundation designs for a crushing mill, primary air fan, and instrument air compressor. The document also lists necessary data that should be obtained from machine manufacturers, such as mass, loading points, anchor bolt details, speeds, and unbalanced forces. Foundation design requires coordination between different engineering disciplines to achieve satisfactory performance, operation, economy, and appearance.
This document outlines specifications for concrete finishers used in construction. It specifies requirements for materials, size, construction, capacity, and performance. Key aspects include:
- Concrete finishers are used after spreaders to finish concrete laid by pavers.
- Materials must meet relevant Indian standards. Common sizes are 3-4.5m and 6-7.5m widths.
- Construction includes a steel frame, traction wheels, steering, adjustable screeds, vibrator attachment, drives, controls, and a diesel or petrol power unit.
- Performance requirements ensure the finisher can operate under different conditions to finish concrete slabs within specifications.
This document provides specifications for concrete spreaders. It outlines various types of concrete spreaders, including reciprocating-blade, screw, and trough-hopper types. It specifies requirements for the size, construction, materials, and performance of concrete spreaders. The construction section describes requirements for the chassis, wheels, scrappers, and operator's station. Tolerances for adjustments to the operating width are also specified.
This document provides information on an Indian Standard for the design and construction of bored cast in-situ concrete piles. Some key points:
- It specifies requirements for bored cast in-situ concrete piles, which are formed by boring a hole in the ground and filling it with concrete.
- Pile capacity depends on skin friction along the shaft and end bearing at the tip. Design must ensure adequate factor of safety and allowable settlement.
- Site investigation data on soil properties, groundwater conditions, and structural loads is required for design.
- Equipment used can include percussion or rotary rigs for boring, and stabilization methods like circulation or suspended mud.
- Design considerations include adjacent structures
This document provides the summary of an Indian Standard code of practice for the design and construction of pile foundations. It specifically focuses on Section 2 which covers bored cast-in-situ concrete piles. Key points include:
1) It establishes terminology for bored cast-in-situ piles which are formed by excavating a hole in the ground and filling it with concrete, with or without a temporary casing.
2) It provides scope and covers the design and construction of bored concrete piles up to 2,500mm in diameter that transmit structural loads through end-bearing and/or shaft friction.
3) The standard references other related Indian Standards and international codes that were consulted in developing this practice.
The document describes Indian Standard code IS:2911 (Part I/Sec I) - 1979 which provides guidelines for the design and construction of driven cast in-situ concrete pile foundations. It covers necessary considerations for pile type, size, installation depth, load testing, and other factors based on site conditions and project requirements. Subsurface investigation data on soil properties, groundwater levels, and chemical testing is required to properly design and install pile foundations. The standard has been revised to incorporate recent developments and separate pile foundation types into distinct sections for ease of use.
This document provides the standard test method for evaluating the performance of screed board concrete vibrators by measuring their ability to compact concrete. The test involves vibrating a 180mm thick concrete slab with a vibrator and taking density measurements from cores cut from the slab. If the density from each core is at least 93% of the maximum theoretical density, the vibrator passes the test. This direct measurement of compaction achieved provides a better assessment of a vibrator's quality than indirect measurements of vibration characteristics alone.
This document provides information on Indian Standard IS:2911 regarding the design and construction of pile foundations. It outlines the necessary members of the committee working on revising the standard. The standard covers driven precast concrete piles, providing guidance on pile design, construction methods, site investigation needs, and other relevant details. It aims to incorporate recent developments in pile foundation engineering practices in India.
This document provides guidelines for designing foundations for rotary machines of low frequency (below 1,500 rpm), such as crushers, pumps, motor generators, compressors, and rolling mill stands. It discusses typical foundation designs for a crushing mill, primary air fan, and instrument air compressor. The document also lists necessary data that should be obtained from machine manufacturers, such as mass, loading points, anchor bolt details, speeds, and unbalanced forces. Foundation design requires coordination between different engineering disciplines to achieve satisfactory performance, operation, economy, and appearance.
This document outlines specifications for concrete finishers used in construction. It specifies requirements for materials, size, construction, capacity, and performance. Key aspects include:
- Concrete finishers are used after spreaders to finish concrete laid by pavers.
- Materials must meet relevant Indian standards. Common sizes are 3-4.5m and 6-7.5m widths.
- Construction includes a steel frame, traction wheels, steering, adjustable screeds, vibrator attachment, drives, controls, and a diesel or petrol power unit.
- Performance requirements ensure the finisher can operate under different conditions to finish concrete slabs within specifications.
This document outlines criteria for the design of solid gravity dams made of masonry or concrete. It discusses forces that should be considered in stability analysis, including dead load, water pressures, uplift, earthquakes, and more. Load combinations are provided that should be used in design, including construction conditions, normal operation, flood discharge, and combinations that include earthquake loads. Guidelines are given for factors of safety depending on load types and material properties. The document aims to rationalize dam design using all available data and account for uncertainties to ensure structural safety.
This document is the Indian Standard Specification for Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement. It outlines requirements for mild steel and medium tensile steel reinforcement bars in round and square sections. The standard covers physical and mechanical properties of the bars, methods for testing, welding requirements, and provides definitions for key terminology. It aims to standardize specifications for reinforcement bars used in concrete structures in India.
This document outlines testing methods to evaluate bond strength between concrete and reinforcing bars. It describes procedures for pull-out tests using concrete cubes with embedded reinforcing bars. Specimen sizes are based on bar diameters up to 25mm being tested in 150mm cubes, and larger bars in 225mm cubes. Apparatus includes molds, dial micrometers to measure slip, and a testing machine capable of pulling the bar at a specified rate while measuring slip.
This document provides the specifications for portable swing weighbatchers used for weighing concrete materials like sand, aggregate and cement. It outlines the key components of single and double bucket weighbatchers including the chassis, swing carriage, weigh buckets, weighing mechanism and wheels. The document specifies material and construction requirements, size and capacity details, and performance standards for weighbatchers. Tolerances of 1% or less for weighing accuracy are required under normal operating conditions.
This document provides guidelines for instrumentation of concrete and masonry dams. It outlines obligatory and optional measurements for dams, including uplift pressure, seepage, temperature, and displacement. Obligatory measurements include uplift pressure, seepage, temperature inside the dam, and displacement measurements using plumb lines or other methods. Optional measurements that may provide additional insights include stress, strain, pore pressure, and seismicity measurements. The document describes different types of measurements in detail and how they can be used to monitor dam performance and safety over time.
This document outlines specifications for reinforced concrete dust bins in India, including:
- Dimensions and reinforcement requirements for circular and square bins of various sizes
- Minimum concrete thicknesses and reinforcement based on bin size
- Door, lid, and drainage hole requirements
- Marking information to be included on each bin
The specifications are intended to standardize dust bin construction across municipalities and organizations in India. Precise dimensions, materials, and construction details are provided to guide manufacturers.
This document provides standards for testing the strength of concrete in India. It outlines procedures for making and curing compression test specimens in a laboratory setting, including sampling materials, mixing, compacting, and curing the concrete specimens. It specifies that test specimens should be 150mm cubes or 150mm diameter cylinders for compressive strength testing. The document also references other Indian standards for materials used in concrete like cement, aggregates, and sieves.
This document provides guidelines for the design and construction of bored precast concrete piles used for foundations. It outlines necessary site investigation information needed, equipment used, and design considerations. Bored precast piles involve boring holes and lowering precast concrete piles that are then grouted in place. Proper site data on soil conditions, groundwater levels, and structural loading is required. Equipment for boring, handling, and grouting the piles must be selected based on subsoil properties. Pile design should ensure loads are safely transmitted to the soil without failure or excessive settlement.
This document provides specifications for concrete pavers. It outlines requirements for the materials, size, construction, capacity, and performance of concrete pavers. Some key points:
1) Concrete pavers are self-contained, self-propelled machines used to distribute concrete for road and runway construction.
2) Common paver sizes are 800 and 1000 liters, with non-tilting concrete mixers and booms that can place concrete from 0.65 to 3 meters above ground level.
3) Specifications include requirements for chassis, mixers, booms, buckets, operator stations, steering, power units, transmissions, controls, maintenance accessibility, interchangeability of parts, and finishing/painting
This document provides specifications for reinforced concrete poles used for overhead power and telecommunication lines. It outlines materials, design requirements, manufacturing process, testing procedures, sampling, inspection and marking. Some key points:
- Concrete poles must be at least 6m long and maximum 9m, in 0.5m increments. Depth of planting depends on pole length, from 1.2m to 1.5m.
- Reinforcement bars and wires must meet specifications. Concrete minimum grade is M25.
- Poles are designed to withstand specified wind loads without failure. Transverse strength must be at least 1/4 of required strength in line direction.
- Manufacturing involves accurate reinforcement placement, proper cover
This document provides the code of practice for external cement concrete facings (Part II). It outlines the necessary information, materials, design considerations, and types of facings and attachment methods for concrete facing work. Some key points include:
- Precast concrete facing blocks must conform to IS 2185-1962 and have special treatment for durability, color, and surface texture. Common facing slab size is 60x40x3 cm.
- Materials for cramps and metal angle supports must resist corrosion. Mortar materials include cement, sand, lime, and surkhi.
- Structural design must consider wind loads per IS 875-1964 and stresses from facing weight.
- There are two
The document provides specifications and guidelines for placing concrete lining in tunnels used to convey water. It discusses requirements for the concrete mix including aggregate size, cement content, and slump. It recommends controlling seepage water and timing the concrete placement based on tunnel conditions. Common sequences for lining placement are described, including first doing the curbs then sides and arch, or first doing the invert then sides and arch. Formwork types including rib and plate, rib and lagging, and travelling shutters are also covered.
This document provides the code of practice for general construction of plain and reinforced concrete for dams and other massive structures in India. It covers materials, concrete mix design, placement, curing, formwork, joints, and testing. The code aims to ensure durability, strength, impermeability and uniformity of concrete structures. It establishes requirements for cement, aggregates, water, admixtures and reinforcement to be used. It also provides guidelines for mixing, placing, compacting, curing concrete and constructing joints.
This document provides the specification for reinforced concrete fence posts according to Indian Standard IS:4996-1984. It outlines the materials, manufacturing process, shape and dimensions, and fixing of fencing wires for reinforced concrete fence posts. Some key points include:
- Cement, water, aggregates and reinforcement materials must meet standards specified.
- Posts are to be manufactured through mixing, placing and compacting concrete to be dense and free of voids.
- Reinforcement is to be properly positioned and anchored with minimum concrete cover requirements.
- Posts must cure for a minimum of 7 days and achieve a strength threshold before handling.
- Dimensions and tolerances are provided, with recommendations for line, strainer
This document provides the specification for prestressed concrete poles used in overhead power transmission and telecommunication lines. It outlines various definitions related to pole design loads and failure conditions. It specifies requirements for materials like cement, aggregates, prestressing steel, and concrete strength. It also describes design considerations such as minimum depth of planting, transverse strength, and load factors. The document outlines manufacturing requirements including placement of reinforcement, prestressing, curing, and earthing. It specifies tests to be conducted during and after manufacture along with sampling and inspection criteria.
This document provides information about the Mahadeopuri mine located in Pench Area, Chhindwara, Madhya Pradesh. It summarizes that the mine uses two inclines for haulage and traveling, produces 250 tons of coal per day transported to a nearby power station, and is currently mining the II (A+B) seam. The mine works using the board and pillar method with a panel system in the 21D section. Details are provided about the geology, workings, haulage system, drilling, blasting, and support rules of the mine.
Drilling is the process of making holes into hard surfaces like rock. In surface mining, drilling is used for blast hole drilling, core drilling for exploration, and technical drilling. Rotary blast hole drilling involves rotating drill pipes to which a bit is attached to break up rock. The main assemblies of a rotary drill rig include the mast, rod changer, rotary head, pull down mechanism, air compressor, drill pipes, hydraulic system, and dust control components.
This document provides unit weights for various building materials and stored materials. It contains 3 tables: Table 1 lists unit weights of individual building materials alphabetically, ranging from acoustical materials to timber. Table 2 lists unit weights of building parts/components such as ceilings, floors, and walls. The Appendix lists unit weights of stored materials including agricultural products, chemicals, fuels, metals and textiles. The document aims to provide weight information to aid in structural design calculations for dead loads in buildings.
This document provides the requirements for immersion type concrete vibrators in India. It summarizes the key details of immersion vibrators including materials used, sizes, construction requirements, performance testing, and marking requirements. The document was revised in 1992 to incorporate modifications based on experience and to include provisions for pendulum type vibrators. It aims to provide guidance for both manufacturing and purchasing immersion vibrators to ensure satisfactory performance.
This document is the Indian Standard specification for pneumatic concrete breakers from 1966. It defines three classes of concrete breakers based on weight as light (under 20kg), medium (20-32kg), and heavy (32-40kg). It specifies dimensions for tool shanks that connect to the breakers and describes the required construction of the back head assembly, cylinder assembly, and front head assembly. Performance and testing requirements are also specified to ensure breakers meet standards.
This document provides the specification for concrete masonry units including hollow and solid concrete blocks. It defines key terms, specifies dimensions and tolerances for blocks, and classifies blocks into different grades based on their density and compressive strength. The standard aims to promote the use of concrete masonry in construction by specifying requirements for different types of blocks to allow for load-bearing and non-load-bearing walls as well as other applications.
This document outlines criteria for the design of solid gravity dams made of masonry or concrete. It discusses forces that should be considered in stability analysis, including dead load, water pressures, uplift, earthquakes, and more. Load combinations are provided that should be used in design, including construction conditions, normal operation, flood discharge, and combinations that include earthquake loads. Guidelines are given for factors of safety depending on load types and material properties. The document aims to rationalize dam design using all available data and account for uncertainties to ensure structural safety.
This document is the Indian Standard Specification for Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement. It outlines requirements for mild steel and medium tensile steel reinforcement bars in round and square sections. The standard covers physical and mechanical properties of the bars, methods for testing, welding requirements, and provides definitions for key terminology. It aims to standardize specifications for reinforcement bars used in concrete structures in India.
This document outlines testing methods to evaluate bond strength between concrete and reinforcing bars. It describes procedures for pull-out tests using concrete cubes with embedded reinforcing bars. Specimen sizes are based on bar diameters up to 25mm being tested in 150mm cubes, and larger bars in 225mm cubes. Apparatus includes molds, dial micrometers to measure slip, and a testing machine capable of pulling the bar at a specified rate while measuring slip.
This document provides the specifications for portable swing weighbatchers used for weighing concrete materials like sand, aggregate and cement. It outlines the key components of single and double bucket weighbatchers including the chassis, swing carriage, weigh buckets, weighing mechanism and wheels. The document specifies material and construction requirements, size and capacity details, and performance standards for weighbatchers. Tolerances of 1% or less for weighing accuracy are required under normal operating conditions.
This document provides guidelines for instrumentation of concrete and masonry dams. It outlines obligatory and optional measurements for dams, including uplift pressure, seepage, temperature, and displacement. Obligatory measurements include uplift pressure, seepage, temperature inside the dam, and displacement measurements using plumb lines or other methods. Optional measurements that may provide additional insights include stress, strain, pore pressure, and seismicity measurements. The document describes different types of measurements in detail and how they can be used to monitor dam performance and safety over time.
This document outlines specifications for reinforced concrete dust bins in India, including:
- Dimensions and reinforcement requirements for circular and square bins of various sizes
- Minimum concrete thicknesses and reinforcement based on bin size
- Door, lid, and drainage hole requirements
- Marking information to be included on each bin
The specifications are intended to standardize dust bin construction across municipalities and organizations in India. Precise dimensions, materials, and construction details are provided to guide manufacturers.
This document provides standards for testing the strength of concrete in India. It outlines procedures for making and curing compression test specimens in a laboratory setting, including sampling materials, mixing, compacting, and curing the concrete specimens. It specifies that test specimens should be 150mm cubes or 150mm diameter cylinders for compressive strength testing. The document also references other Indian standards for materials used in concrete like cement, aggregates, and sieves.
This document provides guidelines for the design and construction of bored precast concrete piles used for foundations. It outlines necessary site investigation information needed, equipment used, and design considerations. Bored precast piles involve boring holes and lowering precast concrete piles that are then grouted in place. Proper site data on soil conditions, groundwater levels, and structural loading is required. Equipment for boring, handling, and grouting the piles must be selected based on subsoil properties. Pile design should ensure loads are safely transmitted to the soil without failure or excessive settlement.
This document provides specifications for concrete pavers. It outlines requirements for the materials, size, construction, capacity, and performance of concrete pavers. Some key points:
1) Concrete pavers are self-contained, self-propelled machines used to distribute concrete for road and runway construction.
2) Common paver sizes are 800 and 1000 liters, with non-tilting concrete mixers and booms that can place concrete from 0.65 to 3 meters above ground level.
3) Specifications include requirements for chassis, mixers, booms, buckets, operator stations, steering, power units, transmissions, controls, maintenance accessibility, interchangeability of parts, and finishing/painting
This document provides specifications for reinforced concrete poles used for overhead power and telecommunication lines. It outlines materials, design requirements, manufacturing process, testing procedures, sampling, inspection and marking. Some key points:
- Concrete poles must be at least 6m long and maximum 9m, in 0.5m increments. Depth of planting depends on pole length, from 1.2m to 1.5m.
- Reinforcement bars and wires must meet specifications. Concrete minimum grade is M25.
- Poles are designed to withstand specified wind loads without failure. Transverse strength must be at least 1/4 of required strength in line direction.
- Manufacturing involves accurate reinforcement placement, proper cover
This document provides the code of practice for external cement concrete facings (Part II). It outlines the necessary information, materials, design considerations, and types of facings and attachment methods for concrete facing work. Some key points include:
- Precast concrete facing blocks must conform to IS 2185-1962 and have special treatment for durability, color, and surface texture. Common facing slab size is 60x40x3 cm.
- Materials for cramps and metal angle supports must resist corrosion. Mortar materials include cement, sand, lime, and surkhi.
- Structural design must consider wind loads per IS 875-1964 and stresses from facing weight.
- There are two
The document provides specifications and guidelines for placing concrete lining in tunnels used to convey water. It discusses requirements for the concrete mix including aggregate size, cement content, and slump. It recommends controlling seepage water and timing the concrete placement based on tunnel conditions. Common sequences for lining placement are described, including first doing the curbs then sides and arch, or first doing the invert then sides and arch. Formwork types including rib and plate, rib and lagging, and travelling shutters are also covered.
This document provides the code of practice for general construction of plain and reinforced concrete for dams and other massive structures in India. It covers materials, concrete mix design, placement, curing, formwork, joints, and testing. The code aims to ensure durability, strength, impermeability and uniformity of concrete structures. It establishes requirements for cement, aggregates, water, admixtures and reinforcement to be used. It also provides guidelines for mixing, placing, compacting, curing concrete and constructing joints.
This document provides the specification for reinforced concrete fence posts according to Indian Standard IS:4996-1984. It outlines the materials, manufacturing process, shape and dimensions, and fixing of fencing wires for reinforced concrete fence posts. Some key points include:
- Cement, water, aggregates and reinforcement materials must meet standards specified.
- Posts are to be manufactured through mixing, placing and compacting concrete to be dense and free of voids.
- Reinforcement is to be properly positioned and anchored with minimum concrete cover requirements.
- Posts must cure for a minimum of 7 days and achieve a strength threshold before handling.
- Dimensions and tolerances are provided, with recommendations for line, strainer
This document provides the specification for prestressed concrete poles used in overhead power transmission and telecommunication lines. It outlines various definitions related to pole design loads and failure conditions. It specifies requirements for materials like cement, aggregates, prestressing steel, and concrete strength. It also describes design considerations such as minimum depth of planting, transverse strength, and load factors. The document outlines manufacturing requirements including placement of reinforcement, prestressing, curing, and earthing. It specifies tests to be conducted during and after manufacture along with sampling and inspection criteria.
This document provides information about the Mahadeopuri mine located in Pench Area, Chhindwara, Madhya Pradesh. It summarizes that the mine uses two inclines for haulage and traveling, produces 250 tons of coal per day transported to a nearby power station, and is currently mining the II (A+B) seam. The mine works using the board and pillar method with a panel system in the 21D section. Details are provided about the geology, workings, haulage system, drilling, blasting, and support rules of the mine.
Drilling is the process of making holes into hard surfaces like rock. In surface mining, drilling is used for blast hole drilling, core drilling for exploration, and technical drilling. Rotary blast hole drilling involves rotating drill pipes to which a bit is attached to break up rock. The main assemblies of a rotary drill rig include the mast, rod changer, rotary head, pull down mechanism, air compressor, drill pipes, hydraulic system, and dust control components.
This document provides unit weights for various building materials and stored materials. It contains 3 tables: Table 1 lists unit weights of individual building materials alphabetically, ranging from acoustical materials to timber. Table 2 lists unit weights of building parts/components such as ceilings, floors, and walls. The Appendix lists unit weights of stored materials including agricultural products, chemicals, fuels, metals and textiles. The document aims to provide weight information to aid in structural design calculations for dead loads in buildings.
This document provides the requirements for immersion type concrete vibrators in India. It summarizes the key details of immersion vibrators including materials used, sizes, construction requirements, performance testing, and marking requirements. The document was revised in 1992 to incorporate modifications based on experience and to include provisions for pendulum type vibrators. It aims to provide guidance for both manufacturing and purchasing immersion vibrators to ensure satisfactory performance.
This document is the Indian Standard specification for pneumatic concrete breakers from 1966. It defines three classes of concrete breakers based on weight as light (under 20kg), medium (20-32kg), and heavy (32-40kg). It specifies dimensions for tool shanks that connect to the breakers and describes the required construction of the back head assembly, cylinder assembly, and front head assembly. Performance and testing requirements are also specified to ensure breakers meet standards.
This document provides the specification for concrete masonry units including hollow and solid concrete blocks. It defines key terms, specifies dimensions and tolerances for blocks, and classifies blocks into different grades based on their density and compressive strength. The standard aims to promote the use of concrete masonry in construction by specifying requirements for different types of blocks to allow for load-bearing and non-load-bearing walls as well as other applications.
This document provides specifications for concrete vibrating tables. It outlines requirements for materials, design, size, capacity and motive power of vibrating tables. Tables are designated by their length and breadth in meters and have minimum capacities of 0.5, 1 or 1.5 tonnes depending on their size. Materials must meet relevant Indian standards and tables can be powered by an eccentric rotor, engine, pneumatic power or electromagnetic pulsators. The document establishes performance testing methods and ensures tables effectively compact concrete in molds.
This document specifies requirements for flexible shafts used in concrete vibrators. It defines terminology such as inner shaft, outer casing, and end fittings. It outlines two types of flexible shafts based on end fitting form. Dimension requirements include diameters of 10-15 mm and lengths of 4-6 meters for the inner shaft. Material requirements specify spring steel for the inner shaft and rubber with a steel liner for the outer casing. Tests are described to check for flaws, flexibility, and locking diameter. Markings must include the designation and manufacturer. Figures provide examples of assembly configurations and end fitting dimensions.
This document is the Indian Standard for prestressed concrete pipes and specials. It lays out requirements and specifications for two types of prestressed concrete pipes - prestressed concrete cylinder pipes and prestressed concrete non-cylinder pipes. It covers materials, dimensions, tolerances, design criteria, testing procedures, and other technical details for the manufacture and use of these pipes. The standard was originally published in 1959 and revised in 1978 and 2001, with the latest revision incorporating modifications to design aspects, inclusion of design examples and inspection procedures, and an increased diameter range for the pipes.
This document provides safety guidelines for piling and other deep foundation construction work. It outlines general safety requirements including safety programs, fencing of work areas, investigation of underground utilities, and provision of protective equipment. It then provides specific safety measures for operation and maintenance of piling rigs, including requirements for rig stability, enclosure of moving parts, inspection of equipment, hoisting loads, and electrical safety. Guidelines are also given for floating pile drivers, including provision of boats, signaling equipment, fire protection, and ensuring stability of floating equipment.
This document provides details on an Indian standard for concrete vibrators of the screed board type. It outlines:
1. The scope, covering materials, sizes, construction, assembly and performance of screed board concrete vibrators.
2. Terminology for key terms like amplitude of vibration, eccentric shaft, screed board, vibrating unit, etc.
3. Material requirements for parts like the eccentric shaft, tube, rivets, springs and V-belts.
4. Common size designations for screed board vibrators of 3, 4 and 5 meters in length.
5. Construction details covering the mounting of the vibrating unit, positioning, enclosure, lubrication and
This document provides recommendations for using table vibrators to consolidate concrete. It discusses general considerations like the suitability of table vibrators, power units, handling the vibrator, and performance and sizing of vibrators. It also covers concrete mix design, formwork design, and testing of vibrating tables according to relevant Indian Standards. The key points are that table vibrators are well-suited for precast concrete elements, proper power units and maintenance are important, and concrete mix workability and form rigidity affect vibration effectiveness.
This document provides a code of practice for the construction of autoclaved cellular concrete block masonry. It outlines materials and design considerations for constructing load-bearing and non-load bearing walls using these blocks. The document discusses block requirements, mortar mixes, wall thickness, bracing, and modular coordination. It aims to help builders properly use this type of masonry and ensure structural safety and avoidance of cracks.
The document is an Indian Standard code of practice for installing joints in concrete pavements. It provides definitions for different types of joints and pavements. It outlines design considerations for the layout and details of transverse and longitudinal joints. It specifies requirements for materials used in joints like joint filler, sealing compounds, and dowel bars. It describes the purpose and details of transverse expansion joints, contraction joints, and construction joints. The code aims to provide guidance on installing joints to control cracking and allow for movement in concrete pavements.
This document provides the specifications for form vibrators used for compacting concrete. It outlines the different types of form vibrators, including fixed or clamp type vibrators and manual type vibrators. It specifies requirements for materials, sizes, construction, and performance of form vibrators. Key details include acceptable materials for components, acceptable size designations based on power unit capacity and vibrator type, and construction requirements for fixed/clamp and manual vibrator types. The document aims to provide guidance to manufacturers and users on obtaining vibrators capable of satisfactory service for concrete compaction.
This document provides the specifications for precast reinforced concrete street lighting poles. It outlines the materials, design considerations, testing requirements and more. Some key points:
- Poles must be a minimum of 5.2m in length, with mounting heights of at least 4m and planting depths of at least 1.2m.
- Concrete grade shall be at minimum M20. Reinforcement can be mild steel, medium tensile steel or deformed steel bars.
- Poles shall be designed to resist a maximum bending moment from loads like wind pressure and the weight of fixtures applied 600mm below the light source.
- Testing includes determining the ultimate transverse load at which the pole fails under a load
This document outlines specifications for precast concrete coping blocks. It specifies requirements for materials used in manufacturing coping blocks such as cement, aggregates, additives, and concrete strength. It also provides dimensions and tolerances for the cross-section and length of coping blocks. The specifications are intended to ensure coping blocks effectively prevent water penetration, direct water away from walls, resist displacement forces, allow for movement, and provide durability.
This document is the Indian Standard specification for coarse and fine aggregates from natural sources for use in concrete. It outlines various requirements for aggregates including limits on deleterious materials, aggregate crushing value, impact value, abrasion value, and soundness. It defines terms related to aggregates and specifies four grading zones for fine aggregates of different particle sizes. The standard is intended to ensure aggregates are suitable for producing durable concrete structures.
This document is the Indian Standard specification for coarse and fine aggregates from natural sources for use in concrete. It outlines the requirements and limits for quality parameters like deleterious materials, aggregate crushing value, impact value, abrasion value and soundness. It defines terms related to aggregates and specifies four grading zones for fine aggregates of progressively finer sizes. The standard is intended to cover aggregates commonly available in India for general structural and mass concrete construction.
This document provides guidelines for the design and construction of raft foundations. It discusses different types of raft foundations and factors to consider in the design such as allowable bearing pressure, depth of foundation, subsoil water pressure, properties of the supporting soil, rigidity of the foundation and superstructure, and methods of analysis. The main methods of analysis described are the conventional or rigid foundation method based on linear distribution of contact pressure, and simplified flexible foundation methods. Design parameters like modulus of elasticity and subgrade reaction are also addressed.
This document outlines general requirements for the design and construction of concrete structures intended for liquid storage. It establishes standards for concrete structures storing liquids in India. Requirements specific to reinforced concrete structures are covered in Part II of the code. The code does not address structures for storing hot liquids, liquids of low viscosity/high penetration, or non-aqueous liquids that could chemically attack concrete. Materials requirements refer to standards IS: 456-1964 and IS: 1343-1960.
This document provides specifications for precast concrete kerbs, channels, edgings, quadrants, and gutter aprons. It outlines materials requirements including cement, aggregates, and concrete strength. It describes standard section dimensions and tolerances. Finish and color can be specified by the purchaser, with natural being default. The document aims to incorporate revisions from updated related standards to align with current Indian precast concrete industry practices.
This document provides a 3-sentence summary of the petrographic examination methods for aggregates used in concrete as outlined in the Indian Standard IS: 2386 (Part VIII) - 1963:
The standard describes Method I for routine petrographic examination which involves visually inspecting and segregating coarse and fine aggregate constituents based on petrographic and chemical differences across various sieve sizes. Method II is for detailed investigations and serves as the reference method. Both methods require examination of aggregate fractions by a qualified petrographer to identify coatings, minerals, particle shape and other properties that could impact the quality and durability of concrete.
The document provides specifications for precast prestressed concrete street lighting poles. It outlines requirements for materials, design, testing, and other technical details. Key points include:
- It specifies requirements for cement, aggregates, reinforcement, concrete, and admixtures to be used in manufacturing the poles.
- Design specifications include minimum pole length, depth of planting, distances from luminaire to light source, and standard outreach lengths. Poles must be designed not to fail due to compression of concrete.
- Technical details covered include tolerances on dimensions, sampling and inspection procedures, marking requirements, and other quality control aspects.
This document is the Indian Standard Specification for Concrete Masonry Units Part I: Hollow and Solid Concrete Blocks. It outlines specifications for the production of hollow and solid concrete blocks used in load-bearing and non-load-bearing walls. The standard specifies dimensions, tolerances, classifications based on density and compressive strength, and physical properties for the blocks. It provides requirements for hollow and solid concrete blocks to ensure quality, durability and structural integrity in masonry construction.
This document provides standards for hollow and solid lightweight concrete blocks used in construction. It specifies:
1) Two grades (A and B) for load-bearing blocks based on intended use and weather protection.
2) Nominal dimensions for blocks ranging from 100-600mm in length, 50-300mm in width, and 100-200mm in height.
3) Tolerances of +/-5mm for length and +/-3mm for height and width.
4) Requirements for block density, compressive strength, water absorption, and drying shrinkage that vary based on grade.
This document provides design tables for concrete structures used to store liquids. It includes tables for moment coefficients, shear coefficients, and other structural design values for rectangular and cylindrical concrete tanks. The tables are intended to aid engineers in quickly designing these types of structures. Rectangular tank tables cover individual wall panels and continuous walls, while cylindrical tank tables are also provided. Considerations for underground tanks subjected to earth pressures are discussed.
This document outlines test methods for determining various properties of aggregates used in concrete from the Indian Standard IS:2386 (Part III) - 1963. It describes 4 methods (I-IV) for determining specific gravity, apparent specific gravity, water absorption and bulk density of aggregates. Method I is for aggregates larger than 10mm, Method II for aggregates between 40mm and 10mm, Method III for aggregates smaller than 10mm. The tests involve weighing samples in and out of water, surface drying, oven drying and calculating properties from weight changes. Reporting of individual and mean test results is recommended.
This document outlines testing procedures for evaluating the strength, deformation, and cracking of autoclaved cellular concrete flexural members under short duration bending loads. Key points:
- Test specimens should be full-size structural members to be used in construction.
- Members are simply supported and loaded at third points using steel plates to distribute the load evenly.
- Loads, deflections at mid-span, strains, and crack widths are measured.
- Members are loaded until cracking occurs or a prescribed load is reached to evaluate strength, deformation, and cracking behavior under short term bending loads.
This document provides the code of practice for the design and construction of conical and hyperbolic paraboloidal shell foundations. It discusses the preliminary design considerations for shell foundations, including determining the soil design to proportion the foundation dimensions based on allowable bearing pressure and net loading intensity, as well as the structural design of the shell. It also provides figures illustrating reinforcement details for conical and hyperbolic paraboloidal shell foundations. The code covers the relevant terminology and information needed for design, and notes the membrane analysis approach is commonly used for structural design of shell foundations.
28-5.21 Company Profile of Pyrmaid structural consultant.pptxBoopathi Yoganathan
Pyramid Structural Consultant provides structural design, building approval, and construction services. They have a team of experienced engineers and workers who use software like AutoCAD and STAAD to complete structural designs for RCC and steel buildings. Notable projects include the design of a G+1 residential building in Namakkal. They are located in Puduchatram, Namakkal and can be found on LinkedIn and Facebook.
This document provides a bonafide certificate for a project report on the study of mechanical properties of eco-friendly economic concrete. It certifies that the project was conducted by three students, M.Vineeth, Y.Boopathi, and P.Murali, in partial fulfillment of their Bachelor of Engineering degree from Kongu Engineering College. The project investigated replacing natural aggregates with steel slag aggregates and M-sand to produce more sustainable concrete. Tests were conducted to determine the compressive strength, split tensile strength, modulus of rupture, and modulus of elasticity of concrete mixes with varying replacement levels.
The document describes an experimental investigation into the properties of concrete with different replacement percentages of natural aggregates with manufactured sand and steel slag. The methodology involves collecting cement, fine aggregates (natural sand and m-sand), coarse aggregates, and steel slag. The mix design for M20 grade concrete is calculated and concrete specimens are cast. The specimens are cured and then tested to determine their mechanical properties. The results are compared to those of conventional concrete to evaluate the suitability of manufactured sand and steel slag as partial replacements for natural aggregates in concrete.
The document discusses two methods for mesh refinement - the p-method and h-method. The p-method increases the order of the polynomial used in the finite element model, allowing for more accurate results without changing the mesh. The h-method reduces the size of elements to create a finer mesh, better approximating the real solution in areas of high stress gradients. Both methods aim to improve the accuracy of finite element analysis results, with the p-method doing so without requiring changes to the mesh.
This document provides guidance on using epoxy injection to repair cracks in concrete structures. The method involves drilling holes along cracks, injecting epoxy under pressure, and allowing it to seep into the cracks. It can repair cracks as small as 0.002 inches. Epoxy injection requires skilled workers and specialized equipment. While it can effectively repair cracks temporarily, the underlying issues causing the cracks may remain if not addressed.
An embedded system is a dedicated computer system that performs specific tasks. An important application of embedded systems is anti-lock braking systems (ABS) in automobiles. ABS uses sensors and electronic control modules to monitor wheel speed and automatically modulate brake pressure to prevent wheel lockup and maintain steering control during emergency braking. By preventing skidding, ABS can help drivers stop more safely and shorten stopping distances on wet or slippery surfaces compared to standard brakes. ABS works by pulsing the brakes rapidly when it detects a wheel is about to lock up, which allows the wheel to continue turning and maintaining traction with the road.
This document discusses past earthquakes in India and retrofitting techniques for masonry structures. It summarizes the 2004 Indian Ocean earthquake and tsunami, which had a magnitude of 9.1-9.3 making it one of the largest ever recorded. Over 230,000 people were killed across 14 countries by the resulting tsunamis. The document then discusses failure modes of confined masonry walls and retrofitting techniques to improve seismic resistance, including adding horizontal reinforcement, improving wall density and tie columns. Key factors for seismic resistance of confined masonry structures are also summarized.
The document provides guidelines for selecting, splicing, installing, and protecting open cable ends for resistance-type measuring devices in concrete and masonry dams. It discusses cable specifications, approved splicing methods including vulcanized rubber splices, rubber sleeve covering, and self-bonding tape. It also covers cable and conduit selection, including choosing the proper conduit size based on the number and size of cables to be run. Proper installation techniques are outlined to protect cable runs within concrete structures.
This document provides information on an Indian Standard (IS) for a unified nomenclature of workmen for civil engineering. It was adopted in 1982 by the Indian Standards Institution Construction Management Sectional Committee. The standard aims to unify the different names used for workmen engaged in civil engineering works across India. It then lists the unified nomenclature for various types of workmen and for carts/animals commonly used in civil engineering works.
This document provides details on the design and construction of floors and roofs using precast reinforced or prestressed concrete ribbed or cored slab units. It specifies dimensions for the precast units, including widths up to 3000mm for ribbed units and 2100mm for cored units. It also provides requirements for material strengths, structural design considerations, and loads to be accounted for in design according to other relevant Indian Standards.
This document provides definitions for key terms related to concrete monolith structures used in port and harbour construction. It defines elements like the bottom plug, cutting edge, deck slab, dewatering, fascia wall, filling, kentledge, kerb, and monolith. A monolith is a large hollow rectangular or circular foundation sunk as an open caisson through various soil strata until reaching the desired founding level, at which point the bottom is plugged with concrete.
The document provides specifications for an apparatus used to measure the length change of hardened cement paste, mortar, and concrete. It describes the construction, dimensions, materials, and markings required for a length comparator, which uses a micrometer to measure the change in length of specimens against a reference bar. The length comparator consists of an adjustable frame that holds either a screw or dial micrometer and allows measurement of specimens of different lengths.
This document provides guidelines for designing drainage systems for earth and rockfill dams. It discusses key considerations like controlling pore pressures, internal erosion, and piping. The guidelines cover selecting appropriate drainage features based on the dam type and materials. Features discussed include inclined/vertical filters, horizontal filters, longitudinal and cross drains, transition zones, rock toes, and toe drains. Filter material criteria and design procedures are also outlined.
This document provides recommendations for welding cold-worked steel bars used for reinforced concrete construction according to Indian Standard IS 9417. It summarizes the key welding processes that can be used including flash butt welding, shielded metal arc welding, and gas pressure welding. For each process, it outlines preparation of the bars, selection of electrodes, welding procedures, and safety requirements. Diagrams are provided to illustrate edge preparation and sequences for multi-run butt welding and lap welding joints.
This document provides guidelines for lime concrete lining of canals. It discusses materials used for lime concrete lining such as lime, sand, coarse aggregate and water. It also discusses preparation of subgrade for different soil types including expansive soils, rock and earth. Compaction methods are provided for different soil types. The document also discusses laying of concrete lining and provides specifications for lime concrete mix such as minimum compressive and flexural strength.
This document provides guidelines for structural design of cut and cover concrete conduits meant for transporting water. It outlines various installation conditions for underground conduits and describes how to calculate design loads from backfill pressure, internal/external water pressure, and concentrated surface loads. Design loads include vertical and lateral pressure from backfill based on fill material properties, hydrostatic pressure from water surcharge, and dispersed point loads accounting for fill height and conduit geometry. The conduit is to be designed for the most unfavorable combination of these loads. Recommended fill material properties and methods for load and stress analysis are also provided.
This document provides guidelines for installing and observing cross arms to measure internal vertical movement in earth dams. It describes the components of the mechanical cross arm installation including the base extension, cross arm units, spacer sections, and top section. It provides details on installing each component as the dam is constructed in rock-free or rocky soils. Observation involves using a measuring torpedo attached to a steel tape or cable to take settlement readings from the installed cross arm system.
This document provides guidelines for selecting measurement instruments and their locations for monitoring earth and rockfill dams. It describes various types of measurements needed, including pore pressure, movements, seepage, strains/stresses, and dynamic loads from earthquakes. Planning the instrumentation system is important to ensure required data is obtained during construction and the dam's lifetime. The document discusses different instruments for measuring vertical and horizontal movements, such as surface markers, cross-arm installations, hydraulic devices, magnetic probes, and inclinometers.
This document provides methods for determining the concentration of water soluble chlorides in concrete admixtures. It outlines three methods: volumetric, gravimetric, and turbidimetric. The volumetric and gravimetric methods are appropriate for higher chloride concentrations above 1% and 2.5% respectively. The turbidimetric method can detect lower concentrations down to 2 ppm. The document specifies reagents and procedures for each method.
This document provides guidelines for designing, installing, observing, and maintaining uplift pressure pipes for hydraulic structures built on permeable foundations. It discusses how water seepage below these structures can cause uplift pressures that impact stability if not properly accounted for. The standard provides recommendations on locating pressure tapping points along horizontal floors, vertical cut-offs, and at various subsoil depths to monitor pressures and ensure design assumptions remain valid. Regular observation of pressure readings is important for both assessing safety and maintenance of these types of hydraulic structures.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
1. Indian Standard
IS:3558 - 1983
( RealTiied 1990 )
CODE OF PRACTICE FOR
USE OF IMMERSION VlBRATORS FOR
CONSOLIDATING CONCRETE
( First Revision )
Second Reprint APRIL 1997
UDC 666.97.033.16
@ Coj~ytipk 1983
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI’1 10002
Cr5 August 1983
( Reaffirmed 1999 )
2. IS:3558 - 1983
( Rcafliimed 1990)
indian Standard
CODE OF PRACTICE FOR
USE OF IMMERSION VlBRATORS FOR
CONSOLIDATING CONCRETE
( First Revision )
Construction Plant and Machinery Sectional Committee, BDC 28
Chairman
M~J-GEN J. S. SOIY
Represenfrng
Indian Road Construction Corporation Ltd, New
Delhi
Members
Dr K. APRAXZYAX Bharat Earth Movers Ltd, Bangalore
SHRI K. S.P~u~.~wan~~a;v (.ifternate)
SHRI J. M. BASU National Projects Construction Corporation Ltd,
New Delhi
SFIRI S. L. HHATI-4 Beas Dams Project, Talwara
SHRI R. K. MALHOTRA (dkernate)
CHIEF EN~INEXB (Elec) I Central Public Works Department
SUPERINTENOINO ENOINI~ER,
( DELIZI CENTRAL ELEC CIIL(-LE )
( AztLlnate )
SERI ASHOK D’PAL Vak Engineering Pvt Ltd, Madras
DIRECTOR ( P & M ) Central Water Commission
DEPUTY DIRZCTOI: ( P & M ) ( Alterante )
kwN.S. GILL, Punjab Irrigation & Power Department,
Chandigarh
SHRI Y. L. SADANA ( dlternafe )
SHRI V. GULATI Heatly & Gresham ( India) Ltd, New Delhi
SHRI S. A. MENEZES ( Alternate )
JOINT DIRECTOR (WORKS ) Railway Board ( Ministry of Railways )
JOINT DIRECTOR ( CIV ENC~ ) ( Alternofe )
MAJ-GEN P. N. KAPOO~ Research & Development Organisation ( Ministry
of Defence )
SHRI S. N. SIDHAHTI ( Alternate )
SHRI J. P. KAIXIHISH Ccnt;~or~ui~din, Research Institute ( CSIR ),
SARI S. S. WADHWA ( Alternate )
( Conlinucd on page 2 )
0 copgnght 1983
BUREAU OF INDIAN STANDARDS
This publication is protected under the Indian Copyrighf ,4cf (XIV of 1957) and
reproduction in whole or in part by any means except with written permission of the
publisher shall be deemed to be an infringement of copyright under the said Act.
3. IS:3558-1983
(Continucdfrom pug.3 1)
Members Representing
SHRI S. K. KELAVIUR Marshall Sons & Co Manufactrtring Ltd, Madras
SHRI B. V. K. ACJMH. ( Alternate 1I
SHRI S. Y. KHAN
SHRI A. MlSRRA ( Alternafe )
SHRI K. K. KHANNA
SHRI A. C. MENON ( Altcrnatc )
SHRI V. K. KHANNA
SHJII M. E. MADHUSUDAN
SHIU K. L. NANCXA( Alternate )
bra S. S. MALLICK
SHRI L. M. VERMA (Alternate )
Dr A. K. MULLICK
SHRI R~.TAN LAL ( Alternate )
SHRI J. F. ROBERT Moses
SKRI B. V. B. PA1- _.
Killick Nixon & Co Ltd, Bombay
National Buildings Organization, New Delhi
International Engineering and Construction Co,
Calcutta
Directorate General of Technical Development,
New Delhi
Directorate General Border Roads, New Delhi
Cement Research Institute of India, Ne, Delhi
Sahavak Engineering Pvt Ltd, Hyderabad
The Concrete Asrociation of India, Bombay
1SHRI Y. SRINIVASAN ( Alternate
SHRI L. D. PAT?ZL Sayaji Iron & Engineering Co Pvt Ltd, Vadodara
SHRI A. VENKAT~SHAN ( Alternate )
SHRI T. H. PESHORI Recondo Pvt Ltd, Bombay
SHRJ T. H. PESHORI Builders Association of India Ltd, llombav
BHAI TRILOCHAN SINGU ( Alternate )
SHRI N. K. PILLAI Voltas Limited. Bombav
SHRI K. N. RAO Central Mechanical’ Engineering Research
Institute, Dorgapur
Brig M. R. SIKKA Engineer-in-Chief’s Branch, Army Headquarters
LT-COL K. K. SRIVASTA~A (Alternate)
PROF C. G. SWAMINAT~AN Central Road Research Institute (CSIR ), New
Delhi
SHRI P. S. TALATI Hindustan Construction Co Ltd, Bombay
SHRI G. S. GOPALRAO ( Alternate )
SHRI R. K. THAKUR Roads Wing ( Ministry of Shipping & Transport )
SHRI G. VISWANATHAN ( Alternate)
SHRI G. RAMA.N, Director General, IS1 ( &-O&%io Member )
Director ( Civ Engg )
Secretary
SHRI C: K. BEB,+PTA
Senior Deputy Dnector ( IV Engg ), IS1
Panel for Concrete Vibrators, BDC 28: P2
Members
SEBI K. C. Aaonswa~ Hindustan Prefab Ltd, New Delhi
SH~I V. K. MATHW (Alternate)
SH~I M. G. DANDAVATE The Concrete Association of India, Bombay
SHRI N. C. DUQ~AL ( Altcrnntr)
DIRECTOR f P & M 1 Central Water Commission
DEPUTY DIRE&•E ( P & M) ( Alttrnate )
( Continurd on faga 17 )
2
4. IS:3558 -1983
lndian Standard
CODE OF PRACTICE FOR
USE OF IMMERSION VIBRATORS EUR
CONSOLIDATING CONCRETE
( First Revision )
0. FOREWORD
0.1This Indian Standard ( First Revision) was adopted by the Indian
Standards Institution on 24 February 1983, after the draft finalized by rhe
Construction Plant and Machinery Sectional Committee had been
approved by the Civil Engineering Division Council.
0.2 Consolidation of concrete by vibration has almost completely
revolutionized the concept of concrete technology, making possible the
use of low slump stiff mixes for economic production of‘ higil quality
concrete with required strength and impermeability. The use of
vibration may be essential for the production of all good concretes
particularly where the reinforcement is congested or where to produce
quality concrete. Vibration IS often adopted to improve the colnpaction
and strength of concrete. In this way vibration can, rlntler sllitable
conditions, produce better quality concrete than by hand corllpaction, or
by permitting lower cement content and lower water/ctnltnt ratio,
produce equally ‘strong concrete more economically than by hand
compaction.
0.2.1 While vibration properly applied is a great step forward in the
production of quality concrete, it js also employed as a method of placing
ordinary concrete more easily than as a method of obtaining high grade
concrete at an economical cost. All the potential advantages of ,ibration
can be fully realised only if proper control is exercised in the desion
an d manufacture of concrete and certain rules are observed regardi:g
proper use of different types of vibrators. This code covers the use of
immersion type concrete vibrators and is intended to give guidance in
obtaining maximum benefit from the technique of vibration with
immersion vibrators.
0.3 This standard was first published in 1966. Based on the work done at
Central Building Research Institute, Roorkee the frequency of vibration
has been redefined and a service log book for flexible shaft. vibrators has
3
5. IS : 3558 - 1983
been included. Also, the maximum thickness of concrete layer, that can
be comp:lcted, and vibration time for optimum compaction has been
specified in this revision.
0.3.X Essential requirements regarding the quality and manufacture of
concrete suitable for vibration have been covered but detailed methods for
the actual design of concrete mixes have not been included, these being
beyond the scope of this code.
0.4 In the formulation of this standard due weightage has been given
to international co-ordination among the standards and practices
prevailing in different countries in addition to relating it to the practices
in the field in this country.
0.5 For the purpose of deciding whether a particular requirement of this
standard is complied with, the final value, observed or calculated,
expressing the result of a test or analysis, shall be rounded off in
accordance with IS : 2-1’360”. The number of significant places retained
in the rounded off value should be the same as that of the specified value
in this standard.
1. SCOPE
1.1This code deals with the use of immersion vibrators for the
consolidation of concrete, the maintenance of the immersion vibrators in
proper running order, besides giving recommendations regarding placing
of concrete and its consolidation by vibration.
2. TERMINOLOGY
2.0 For the purpose of this code, the definition as given in IS : 2505-1980-t
and the following shall apply.
2.1 Frequency of Vibration - Number of complete cycles of vibration
per second ( Hz ) of the vibrating needle.
3. GENERAL CONSIDERATIONS
3.1 Suitability of Immersion Vibrators
3.1.1 Immersion vibrators can be satisfactorily used for consolidation of
plain as well as reinforced concrete. To ensure their proper use, the
concrete mix shall be properly designed ( see 6 ) and filling of concrete
*Rules for rounding off numerical values ( revised).
tCenera1 requirements for concrete vibrators, immersion type( smnd reui~ion).
4
6. IS : 3558 - 1983
shall he deep enough to allow the vibrating needle to be adequately dipped
either perpendicularlv or at an angle ( see Note ). To be fully effective,
the needle of immersion vibrator shall be completely immersed in concrete.
As a general rule, the depth of concrete layer to be vibrated should be in
the range of 2/3 ‘l’to ‘1’ where ‘1’ is length of vibrating needle. It has
been found that with immersion vibrator, a greater density of the concrete
is obtained at the bottom of the layer then at the top due to compacting
effect of the weight of concrete above and rebound from bottom. There-
fore, it is in general not advisable to have layer thickness greater than
600 mm. The flexible shaft should always be kept clear to prevent
damage to it. Immersion vibrators shall not be used where the thickness
of the concrete is less than 100 mm.
NOTF: - The vibrating nerdle should perfwably bc inwrtrd vertically. The
insertion ar an angle, in th:ck lqen, may leave concrete unconsolidated without any
indication at the surface.
3.1.2 Immersion vibrators to be used for consolidation of concrete may
be either flexible shaft driven or motor-in-head type. Flexible shaft drive
may be either compressed-air or motor or petrol or diesel engine driven.
Motor-in-head type are operated electrically or pneumatically. Motor-
in-head eliminates the limitations of flexible shaft drive as the
maintenance of driving shafts is a problem because their life and
resistance to wear is a function of the relative speed to which they are
subjected.
3.2 Power Unit
3.2.1 The immersion vibrator may be powered by any of the following
power units:
4
b)
c)
3.2.2
Electric motors either driving the vibrator through flexible shaft
or situated at the head of the vibrator,
Internal combustion engine ( petrol or diesel engine j driving the
vibrator needle through flexible shaft, and
Compressed-air motor situated near the head of the vibrator.
Where reliable supplies of electricity are available the electric
motor is generally the most satisfactory and economical power unit. The
speed is relatively constant, cables supplying current are light and easily
handled as the motor itself.
3.2.3 Internal combustion engines are often convenient source of power.
Small petrol engines sometimes ,give trouble at starting and are more
easily put out of action by site conditions compared to electric or com-
pressed-air motors. They should be located conveniently near the work
to be vibrated and should be properly secured to their base.
5
7. IS : 3558 - 1983
3.2.4 Compressed-air motors are generally suitable but their vibrators
are sometimes dillicult to manipulate where the compressor cannot be
placed adjacent to the work in hand such as on high scaffoldings or
at depths below ground level due to heavy weight of air hoses. These
compressed-air vibrators occasionally give trouble, especially in cold
weather, bv freezing at exhaust unless alcohol is trickled into the air line
or dry air is used. Glycol type antifreeze agents tend to cause gumming
of the vibrator valves. There is also a tendency for moisture to collect in
the motor and care should be taken to remove the moisture to
prevent possible damage.
3.2.5 The speed of both the petrol and compressed-air motors tend
to vary giving rise to variation in the compacting effect of the vibrator.
3.2.6 Rating of the Pormr Unit--The power required to operate
vibrators, depends upon the characteristics of the vibrator and varies with
the power unit employed to dri.e the vibrator. The type of power unit
and its rating shall be as specified by the manufacturer of the vibrator.
The following power ratings have generally been found adequate:
Power Unit Poxer Rating
kW
Petrol engines 1’5 to 3.5
Diesel engines Up to 3.3
Electrical motor 0.75 to 2’5
Compressed air operation 7.5
4. HANDLING THE IMMERSION VIBRATOR
4.1 The. vibrators operate under heavy stress and therefore, require
regular maintenance to keep them in proper working order. After
use the vibrators shall be thoroughly cleaned and stored in clean dry
place. All repairs shall be carried out under careful supervision and as
per manufacturer’s instruction. Sufficient stand-by equipment shall
also be provided to keep placement of concrete fully operative when
vibrators are undergoing repairs. Provisions shall be made for
replacement of vibrators that have to be taken out of service .for
maintenance and repair. Where a number of vibrators are being
operated by a contractor or department, it is recommended that service
log book should be maintained as given in Appendix A. The
manufacturer should specify type of lubricant for flexible shaft and
the repair instructions.
4.1.1 The vibrator head is liable to wear off in the course of usage due
to frictional contact with sharp edged stone aggregate of concrete. There
6
8. Is : 3558 - 1983
is also a tendency for the bearings to wear out because of centrifugal
force and the resultant impact. Worn-out parts should be replaced
in time to avoid premature damage to the whole machine.
4.1.2 Care shall be taken that the vibrating head does not come
into contact with hard objects like hardened concrete, steel and wood, as
otherwise the impact may damage the bearings. The power unit should,
as far as possible, be started only when the head is raised or resting on
soft support. Similar precautions shall be observed while introducing or
withdrawing the vibrator in the fresh concrete to be consolidated; when
the space for introduction is narrow, the vibrator should be switched
on only after the vibrator head has been introduced into the concrete. A
bend with a radius less than 500 mm not only reduces the torque capacity
of the flexible shaft drive, but may also lead to earlier failrlre.
Unnecessary sharp bends in the flexible shaft drive shall therefore,
be avoided.
4.2 Overloading of Driving Motor - When the concrete is very stiff
or rough grained, the vibrator will usually be overloaded and the
electric motor may get excessively heated. In such cases, unless the
motor is provided with an automatic cut-off device, it should be switcheti
off and the overload remedied.
4.3 Electrical Protective Devices
4.3.1 If the vibrator is worked by an electric motor, special precautions
shall be taken to protect the operator from shocks. Special protective
measures against too high contact voltage. shall be incorporated by an
authorized installation company in accordance with the requirements 01
IS : 1356 ( Part I )-197’L* and other relevant Indian Standards, current
Indian Electricity Rules and any other regulations in force in the:
particular area. The vibrator shall be adequately earthed to prevem
shock to the operator. The safety lead shall be carried over the
connection; for this purpose four-core rubber-sheathed cable or a similar
wire shall be used.
4.3.2 The safety device shall always be kept in good working order so
as to effectively protect the operator from danger which can be fatal.
The protective device shall be checked every day before the vibrator
is used.
4.3.3 Special attention shall be paid to the connections at the vibrator
and to the plug, since inappropriate in.stallation and handling may lead
to breakage of wire thus causing interruption of the safety lead or
*Specification for electrical equipment 6f aachine tools: Part I Electrical rquipment
of machines for general use ( second rsui&n ).
7
9. IS:3558 - 1983
dangerous contact voltage in the casing. All cord inlets shall be provided
with suitable anti-tension devices.
5. PERFORMANCE AND SIZE OF VIBRATOR
5.X Virbrators conforming to the requirements of IS : 2X%1980* shall be
used. The size and characteristics of the vibrator suitable for a
particular job vary with the mix preparation, quality and workability of
concrete, placing conditions, size and shape of the member and shall be
selected by the engineer-in-charge depending upon various requirements.
Guidance regarding selection of a suitable vibrator may be obtained from
Table 1.
TABLE 1 APPLICATIONS OF IMMERSION VIBRATORS
i) 25 and 35 Plastic (workable ) concrete in very thin members ana
confined places and for fabrication of laboratory test
cppcirnens. Sltitahlp as auxiliary to larger vibrators
in prestressed work where cables and ducts cause
congestion in the forms. Auxiliary vibrations
adjacent to forms of the pavements.
ii) 40 and 50
iii) 60
iv) 75
vl 90
Plastic (workable) concrete’ in thin walls,, columns,
beams, precast piles, light floors, light brld.gc decks
and along construction joints. Auxiliary vibrations
adjacent to forms of the pavements.
Plastic (workable) concrete in general construction such
as walls, columns; beams, precast piles, heavy floors:
bridge deck and roof slabs. Auxiliary vibration
adjacent to forms of mass concrete and pavements.
Mass and structural concrete deposited in increments
up to 2 m3 heavy construction in relatively open
forms, in power houses, heavy bridge piers and
foundations, and for auxiliary vibration in dam
construction near forms and around embedded itcrns
and reinforcing steel.
Mass conctete containing 150 mm aggregate deposited
in increments up to 8 ms, in gravity dams, large
piers, massive walls, etc. Two or more vibrators
will be required to operate simultaneouslv to spread
and consolidate incremerts of concrete of 4 ma or
‘greater volume deposited at one time in the form.
‘General requirements for concrete vibratois, immersion type ( secondreviJion)
8
10. Is : 3558 - 1983
6. CONCRETE MIX
6.1 Correct design of concrete mix and an effective control in the
manufacture of concrete, right from the selection of constituent materials
through its correct proportioning to its placing, is essential to obtain
maximum benefits of vibration. For best results, the concrete to be
vibrated shall be of stiffest possible consistency, generally within a range
of O-75 to 0.85 compacting factor, provided the fine mortar in concrete
shows at least a greasy wet appearance when the vibrator is slowly
withdrawn (see 8.5 ) from the concrete and the material closes over the
space occupied by the vibrator needle leaving no pronounced hole. The
vibration of concrete of very high workability will not increase its strength;
it may on the contrary, cause segregation. Similarly, excessive vibrations
may also lead to segregation of concrete constituent& Formation of
watery laitance on the surface of concrete due to vibration is an
indication that the concrete possesses high to very high workability
and unsuitable for vibration; such laitance may also be noticed when
excessive vibration is applied to concrete of otherwise appropriate
workability. A cIose textured layer of viscous grout may, however, be
allowed.
6.1.1 On the other hand, the mix shall not be so stiff that it is
incompatible with the particular virbrator in use. As a general guide, a
mix will be compatible with a particular vibrator if the hole formed in
the concrete by the vibrator head closes completely as the vibrator is
slowly withdrawn without leaving a cavity. This property is largely
independent of the speed of removal of the vibrator beyond the practical
range of mixes; but within the practical range, the occurrence of a hole
can be avoided by a gradual removal.
6.1.2 It has’ been proved conclusively that the best compaction is
achieved at the resonant conditions. In other words, one should try
to match the frequency of vibration with aggregate size in the concrete
mix. In general, higher aggregate sizes require lower frequency of
vibration and vice versa. Normally, frequencies of lOOHz, 150 Hz and
200 Hz are best suited to the aggregate sizes of 40, 20 and 10 mm.
7. DESIGN OF FORMWORK
7.1 For vibrated concrete, the formwork shall be strong and great
care shall be exercised in its assembly. It shall be designed to take up
increased pressure of concrete and the pressure variations caused in the
neighbourhood of vibrating head which may result in excessive local
stress on the formwork. More exact details on the possible pressures are
not available, and much depends upon the experience and judgement and
the character of work. The joints of the formwork shall be made and
maintained tight and close enough to prevent the squeezing out of grout
9
11. IS : 3558 - 1983
or sucking in of air during vibration. Absence of this precaution may
cause honeycombing in concrete or form rock pockets or gravel streaks
along the cracks impairing the appearance and also weakening the
structure.
7.i.l The amount of mortar leakage or the permissible gap between
sheathing boards will depend on the desired final appearance ofthe work
but normally gaps larger than l-5 mm between the boards shall not
be permitted. Sometimes even narrower joints may be objectionable
from consideration of their effect on the surface appearance of certain
structures. The number of joints shall be made as low as possible
by making the shutter sections large. Applications on the inside of
formwork to prevent the adhesion of concrete should be very thin as
otherwise they may mix with the concrete under the effect of vibration.
8. VIBRATION OF CONCRETE, RECOMMENDED PRACTICES
8.1 The vibrator may be used vertically, horizontally or at an angle
depending upon the nature of the job (see 3.1.1 ). The concrete to be
vibrated shall be placed in position in level layers ofsuitable thickness not
greater than the effective length of the vibrator needle (see 8.2). The
concrete at the surface shall be distributed as horizontally as possible
since the concrete may flow in slopes while being vibrated and may
segregate, particularly when concrete possesses high workability. The
concrete shall, therefore, be of low workability where it is required to be
vibrated on slopes.
8.1.1 The internal vibrator shall not be used to spread the concrete
from the location of a deposition as this can cause considerable segregation
of concrete. It is advisable to deposit concrete well in advance at the
point of vibration. This prevents the concrete from subsiding non-
uniformly and thus prevents the formation of incipient plastic cracks.
When the concrete is being continuously deposited to a uniform depth
along a member, vibrator shall not be operated too near the free end of
the advancing concrete, usually not within one metre of it. Every effort
shall be made to keep the surface of the previously placed layer of
concrete alive so that the succeeding layer can be amalgamated with
it by the vill.ation process. However, if due to unforeseen circumstances
the concrete in underlying layer has hardened to such an extent that it
cannot be penetrated by the vibrator but is still fresh (that is, just after
initial set ), unimposed bond can be achieved between the top and
underlying layer by first sacrifying the lower layer before the new
concrete is placed followed by systematically and thoroughly vibrating the
new concrete.
8.2 Height of Concrete Layer- The concrete shall be placed in
shallow layers consistent with the method being used to place and vibrate
10
12. IS : 3558 - 1983
the concrete. Usually concrete shall be placed in thickness not more
than 600 mm, and on initial placing in thickness not more than 150 mm.
The figure of 600 mm will be lower for concrete with low workability.
The superimposed load increasing with the height of the layer will favour
action of vibrator, but as it is also the path of air forced upwards, it may
trap air rising up by vibration. Very deep layers ( more than 600 mm )
should, therefore, be avoided as far as possible.
8.3 Depth of Immersion of Vibrator - To be fully effective the
active part of the vibrator shall be completely immersed in the concrete
(see 3.1.1 ). Its compacting action can be usually assisted by maintaining
a head of concrete above the active part of vibrator, the primary object of
which is to press down upon and confine the concrete in the zone of
influence of the vibrator. The vibrator head shall be dipped through
the concrete filling to be consolidated to a further depth of 100
to 200 mm in the already consolidated lower layer for effective
homogenuity and bound between layers.
8.4 Spacing and Number of Insertion Positions -The points of
insertion of vibrator in the concrete shall be so spaced that the range
of action overlap to some extent and the freshly filled concrete is
sufficiently consolidated at all locations. The range of action varies with
the characteristics of vibrator and the composition and workability of
concrete. The range of action and the degree of consolidation can be
recognized from the rising air bubbles and the formation of a smooth
close textured surface around the vibrating head. The range of action
can be more accurately determined by the method described in
IS : 2505-1980*. With concrete of workability of 0’75 to 0.85 compacting
factor, the vibrator shall generally be operated at points 350 to 900 mm
apart depending on the rated capacity of the vibrator. The specified
spacing betiveen the dipping positions shall be maintained uniformly
throughout the surface of concrete so that the concrete is uniformly
vibrated.
8.5 Speed of Insertion and Withdrawal of the Vibrating Head -
The vibrating head shall be regularly and uniformly inserted in the
concrete so that it penetrates of its own accord and shall be withdrawn
quite slowly whilst running so as ‘to allow redistribution of concrete in its
wake and allow the concrete to flow back into the hole behind the
vibrator. The rate of withdrawal is determined by the rate at which
the compaction in the active zone is completed. Usually a speed of
20 - 30 mm/s gives sufficient consolidation without undue strain on the
operator. The speed of withdrawal is lower in case of low workability
concrete. Further concrete shall be added as the vibrators are withdrawn
*General requirements for concrete vibrators, immersion type ( secondrevision).
I1
13. IS : 3558 - 1983
so as to maintain the head of the concrete until the lift of the concrete is
completed.
8.6 Duration of Vibration - Newly deposited concrete shall be
vibrated while it is still plastic, preferably immediately after placing.
The next adjacent concrete shall be placed before the initial setting
occurs. The duration of vibration in each position of insertion is
dependent upon the height of layer, the size and characteristics of
vibrator, and the composition and workability of the concrete mix. It is
better to insert the vibrating head at a number of places than to leave
it for a long time in one place as in the latter case there is a tendency for
formation of mortar pocket at the point of insertion of vibl-ator.
8.6.1 The vibrator head shall be kept in one position till the concrete
within its influence is completely consolidated which will be indicated by
formation at the surface of circular shaped laitance of cement mortar,
showing of flattened glistening surface and cessation of the rise of
entrapped air. Vibration shall be discontinued immediately thereafter.
Vibration shall be continued until the coarse aggregate particles have
blended into the surface but have not disappeared.
8.6.2 Time required to effect complete consolidation is readily judged
by the experienced vibrator operator through the feel of the vibrator due
to resumption of frequency of vibration after the short period of dropping
in the frequency when the vibrator is first inserted. Doubt about the
adequacy of vibration should always be resolved by further vibration;
well proportioned concrete of the correct consistency is not readily
susceptible to over vibration. For optimum compaction, a minimum
time of vibration is 90 seconds for mixes with a compacting factor of 0.78
(stiff mixes). This time may be reduced if more workable mixes
are used.
8.7 Vibrating Concrete at Junctions with Hardened Concrete -
In cases where concrete has to be joined with rock or hardened concrete,
the defects can occur owing to the layers nearest to the hardened concrete
not being sufficiently vibrated. In such cases the procedure given
in 8.7.1 shall be followed.
8.7.1 The hardened concrete surface shall be prepared by hacking or
roughening and removing laitance, greasy matter and loose particles.
The cleaned surface shall be wetted. A cement-sand grout of
proportion 1:l’and of creamy consistency shall then be applied to the wet
surface of old concrete and fresh concrete vibrated against it.
8.8 Vibrating the Reinforced Concrete - The reinforcement shall be
designed to leave sufficient space for the vibrating head. The reinforce-
ment or group of reinforcement should be so placed that a space of 75 mm
12
14. IS :3558-1983
exists between the bars or groups of bars to allow the vibrator to pass
freely. The space between the bars in any group may be reduced to
two-thnds of the nominal size of coarse aggregate, where needed. The
total width of each group shall not exceed 250 mm.
8.8.1 When the reinforcement lie very close to each other, greater care
shall be taken in vibrating so that no pockets or collections of the grout
are formed. Except where some of the concrete has already set and
provided that the reinforcement is adequately supported and secured, the
vibrator may be pressed against the reinforcement under exceptional
circumstances.
8.9 Vibrating Near the Formwork - For obtaining a smooth close
textured external surface the concrete shall have sufficient content of low
bleeding grout of thick consistency. The vibrator head shall not be
brought very near the formwork as this may cause formation of water
whirle (stagnations), especially if the concrete contains too little of fine
aggregate. On the other hand, a close textured surface may not be
obtained, if the positions of insertion are too far away from the formwork.
The most suitable distance of the vibrator from the formwork is from
100 to 200 mm. With the vibration done at the correct depth and with
sufficient grout rising up at the formwork, the outside surface will
generally have a closed textured appearance. In the positions of
formwork difficult to reach and in concrete walls less than 300 mm thick
it is preferable to use vibrators of small size which can be brought to the
required place and which will not excessively strain the formwork.
Alternate form of vibrator such as formwork vibrator may also be
considered in such cases.
8.10 Vibrating High Walls and Columns - While designing the
formwork, reinforcement as well as the division of layers for high walls
and columns, it should be kept in mind that with the usual driving shaft
lengths it is not possible to penetrate the vibrating head more than three
metres in the formwork. In the case of higher walls and columns it is
recommended to introduce the shaft driven vibrating needle through a
side opening into the formwork. A suitable guiding device with gutter
like features can be used as a guide for movement near the reinforcement.
For use with high walls and columns, the flexible driving shaft can be
brought to a length of six to eight metres or even more by using adopter
pieces. The motor-in-head type vibrators are more useful for the purpose
in which case a very long current cable can be used for sinking the
vibrator to a greater depth. In fact, for walls less than 300 mm thick, it
is preferable to supplement with the formwork vibrator especially to
avoid seggregation in deep wall due to drop of concrete.
8.11 Over-Vibration - There is a possibility of over-vibration while
trying to achieve thorough vibration, but it is exceedingly unlikely in well
13
15. IS : 3558 - 1983
proportioned mixes
properly designed
containing normal weight aggregates. Generally, with
mixes, extended vibration will be only waste of effort
without any particular advantage to the concrete. However, where the
workability of concrete is high for the conditions of placing, or where the
quantity of mortar is in excess of the volume of voids in the coarse
aggregate, or where the grading of the aggregate is unsatisfactory, over-
vibration will encourage segregation bleeding or both causing the
migration to the surface of the lighter and smaller constituents of the
mix and thus producing a layer of mortar or laitancc on the surface, and
leakage of mortar through defective joints in the formwork. This may
produce concrete with poor resistance to abrasion and attack by various
agencies, such as frost, or may result in planes of weakness where
successive lifts are being placed. If over-vibration occurs it will be
immediately evident to an experienced vibrator operator or supervisor by
a forthy appearance due to the accumulation of many small air bubbles
and the settlement of coarse aggregates beneath the SUIface. These results
are more liable to occur when the concrete is highly workable and the
proper correction will be to reduce the workability ( not the vibration ),
until evidence of over-vibration disappears during the period of vibration
considered necessary for consolidating the concrete and eliminating air
bubble blemishes.
8.12 Re-vibration - Re-vibration is delayed vibration of concrete that
has already been placed and consolidated. It may occur while placing
succeessive layers of concrete, when vibrations in the upper layer of
fresh concrete are transmitted to the underlying layer which has
partially hardened or may be done intentionally to achieve certain
advantages (see 8.12.1 )
8.12.1 Except in the case of exposed concrete ( see 8.12.3) and
provided the concrete becomes again plastic under bibration, re-vibration
is not harmful and may be beneficial. By repeated vibration over a long
period ( repetition of vibration earliest after one hour from the time of
initial vibration ), the quality of concrete may improve because it
rearranges the aggregate particles and eliminates entrapped water from
under the aggregate and reinforcing steel, with the consequent full
contact between mortar and coarse aggregate or between steel and mortar
and thus produces stronger and watertight concrete. Cracks due to
setting as well as other disturbances like hollow space below the
reinforcement bars and below coarse aggregates, may thereby be closed
again provided the concrete becomes plastic again when the vibrator
head is introduced. Controlled re-vibration of conrete may result in
improved compressive and bond strength, reduction of honey-comb,
release of water trapped under horizontal reinforcing bars and removal
of air and water pockets.
14
16. LS : 3558- 1983
8.12.2 Re-vibration is most effective at the lapse of maximum time
after the initial vib.ration, provided the concrete is sufficiently plastic to
allow the vibrator to sink of its own weight into the concrete and make it
again plastic.
8.12.3 On exposed concrete work where appearance is important, care
shall be taken to avoid inserting internal vibrators through the fresh
concrete into a layer of partially hardened concrete below, as this’may
result in the appearance of a wavy line of demarcation between the layers
on the surface. This would be objectionable from considerations of
surface appearance though the quality of concrete may not be impaired.
8.12.4 However, re-vibration shall be done with prior approval of
the engineer-in-charge only since the state of concrete at the time of
re-vibration is very acute. Re-vibration of concrete which does not get
again plastic under re-vibration is definitely harmful leading to fo?mation
of cracks, non-closure of gaps formed by the insertion of vibrators, etc.
8.13 Lightweight-Concrete - In general, principles and recommended
practices for consolidation of concrete ofnormal weight hold good for
concrete made with lightweight aggregates, provided certain precautions
are observed.
8.13.1 There is always a tendency for lightweight pieces of aggregates
to rise to the surface of fresh concrete, particularly under action of over
vibration; and a fairly stiff mix with the minimum amount of vibration
necessary to consolidate the concrete in the forms without honey-comb is
the best insurance against undesirable segregation. The rise of lightweight
coarse aggregate particles to the surface, caused by ‘over vibration’
resulting from too wet a mix, makes finishing difficult if not impossible.
15
17. IS : 3558 - 1983
APPENDIX A
( Clause 4.1. >
SERVICE LOG BOOK FOR FLEXIBLE SHAFT VIBRATORS
Name of manufacturer
Model Serial No. ~~~ _
Date of purchase -_-
Frequency of Preventive Maintenance
Item
Cleaning &r
Inspection
Lubrication ~ Replacement
I
Flexible Shaft
Shaft
Bearings
Vibrator Needle
Seals
Bearings
Oil charges
16
18. IS : 3558- 1983
( Continuedfrom page 2 )
Membsrs Rcpsmting
SHRI V. GULATI Healty & Grrsham (India ) Ltd, New Delhi
Sam S. A. MENEZES ( .4ltcmate )
HEIU, RIGID PAvI”bfENT DIVISION Central Road Research Institute (CSIR ), N’rw
Delhi
SEIU M. DINAKARAN ( Alternate )
SEI:I J, P. KAUSHI~~H Central Building Research Institute ( CSIR ).
Roorkee
SN~I S. S. WADHWA ! Alternote )
SHEI S. Y. KIIAN Killick. Nixon & Co Ltd, Bombay
SHRI J, F. ROBERT MOSES Sahayak Engineering Pvt Ltd, Hyderabad
SHRI A. G. PATEL Millan, Bombay
SHRI N. B. JOSHI ( Altrrnate )
BRIG M. R. SI6gA Engineer-in-Chief’s Branch, Army Hradquarters
LT-COL K. K. SIUVA~TAVA ( Ahnatc )
17
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