The document summarizes key changes made in IS 1893 and IS 13920 seismic codes. Some major changes include:
1) IS 1893 extended design spectra up to 6 seconds, adopted same spectra for all materials, revised response reduction factors and included flat slab buildings.
2) IS 1893 revised hazard estimation and included temporary structures. IS 13920 included collapse mechanism and shear design of beam-column joints.
3) IS 1893 and IS 13920 provided more detailed provisions for irregular structures, infill walls, diaphragm flexibility and structural walls. IS 13920 allowed identification of separate lateral load resisting systems.
The document evaluates the seismic performance of St. Augustine Church in Lubao, Pampanga, Philippines using nonlinear static analysis. It summarizes the church's history and construction materials. A structural model of the church is created in ETABS using material properties obtained from adobe brick testing. Nonlinear static analysis is performed to determine the church's performance at different seismic levels-immediate occupancy, life safety, and collapse prevention. Retrofitting options like shotcrete are presented and their costs estimated to seismically upgrade weak parts of the structure. The analysis shows that portions of the church risk collapse in a major earthquake and retrofitting is recommended to improve seismic resistance.
The document discusses the design of a combined footing to support two columns. It first defines what a combined footing is and why it is used. It then describes the types of combined footings and the forces acting on it. The document provides the design steps for a rectangular combined footing, which include determining dimensions, reinforcement requirements, and design checks. As an example, it shows the detailed design of a rectangular combined footing supporting two columns with loads of 450kN and 650kN respectively. The design includes calculating dimensions, reinforcement, development lengths, and design checks.
This document discusses shear wall analysis and design. It defines shear walls as structural elements used in buildings to resist lateral forces through cantilever action. The document classifies different types of shear walls and discusses their behavior under seismic loading. It outlines the steps for designing shear walls, including reviewing layout, analyzing structural systems, determining design forces, and detailing reinforcement. The document emphasizes the importance of properly locating shear walls in a building to resist seismic loads and minimize torsional effects.
Footings are structural members that support columns and walls and transmit their loads to the soil in a way that does not exceed the soil's load bearing capacity or cause excessive settlement or rotation. There are two main types of isolated column footings: pad footings and sloped footings. The design process for isolated footings includes determining the size, net upward pressure, bending moment, depth, reinforcement, and load transfer requirements. The example provides specifications to design an isolated square footing to support a 400mm x 400mm column with an axial load of 800kn using M-20 concrete and Fe-250 steel, accounting for a soil bearing capacity of 120kn/m2.
This document discusses the design of compression members under uniaxial bending. It notes that columns are rarely under pure axial compression due to eccentricities from rigid frame action or accidental loading. Columns can experience uniaxial or biaxial bending based on the loading. The behavior depends on the relative magnitudes of the bending moment and axial load, which determine the position of the neutral axis. Methods for designing eccentrically loaded short columns include using equations that calculate the neutral axis position and failure mode, or using interaction diagrams that graphically show the safe ranges of moment and axial load.
Footings transfer structural loads from a building to the ground. This document discusses various types of footings and their design procedures. Spread footings are the most common type and are proportioned to have an area large enough that soil and building settlement will be minimized. The general design process involves checking that factored loads are less than the soil's allowable bearing capacity and footing thickness is sufficient to resist punching and beam shear. Reinforcement is calculated and placed to resist bending stresses. Combined and strap footings are also discussed along with their unique design considerations. Brick footings can be used for small residential loads.
1) The document discusses design considerations for columns according to ACI code, including requirements for different types of columns like tied, spirally reinforced, and composite columns.
2) It provides details on failure modes of tied and spiral columns and code requirements for minimum reinforcement ratios, number of bars, clear spacing, cover, and cross sectional dimensions.
3) Lateral reinforcement requirements are discussed, noting ties help restrain longitudinal bars from buckling while spirals provide additional confinement at ultimate load.
This document provides an overview of different seismic analysis methods for reinforced concrete buildings according to Indian code IS 1893-2002, including linear static, nonlinear static, linear dynamic, and nonlinear dynamic analysis. It describes the basic procedures for each analysis type and provides examples of how to calculate design seismic base shear, distribute seismic forces vertically and horizontally, and determine drift and overturning effects. Case studies are presented comparing the results of static and dynamic analysis for regular and irregular multi-storey buildings modeled in SAP2000.
The document evaluates the seismic performance of St. Augustine Church in Lubao, Pampanga, Philippines using nonlinear static analysis. It summarizes the church's history and construction materials. A structural model of the church is created in ETABS using material properties obtained from adobe brick testing. Nonlinear static analysis is performed to determine the church's performance at different seismic levels-immediate occupancy, life safety, and collapse prevention. Retrofitting options like shotcrete are presented and their costs estimated to seismically upgrade weak parts of the structure. The analysis shows that portions of the church risk collapse in a major earthquake and retrofitting is recommended to improve seismic resistance.
The document discusses the design of a combined footing to support two columns. It first defines what a combined footing is and why it is used. It then describes the types of combined footings and the forces acting on it. The document provides the design steps for a rectangular combined footing, which include determining dimensions, reinforcement requirements, and design checks. As an example, it shows the detailed design of a rectangular combined footing supporting two columns with loads of 450kN and 650kN respectively. The design includes calculating dimensions, reinforcement, development lengths, and design checks.
This document discusses shear wall analysis and design. It defines shear walls as structural elements used in buildings to resist lateral forces through cantilever action. The document classifies different types of shear walls and discusses their behavior under seismic loading. It outlines the steps for designing shear walls, including reviewing layout, analyzing structural systems, determining design forces, and detailing reinforcement. The document emphasizes the importance of properly locating shear walls in a building to resist seismic loads and minimize torsional effects.
Footings are structural members that support columns and walls and transmit their loads to the soil in a way that does not exceed the soil's load bearing capacity or cause excessive settlement or rotation. There are two main types of isolated column footings: pad footings and sloped footings. The design process for isolated footings includes determining the size, net upward pressure, bending moment, depth, reinforcement, and load transfer requirements. The example provides specifications to design an isolated square footing to support a 400mm x 400mm column with an axial load of 800kn using M-20 concrete and Fe-250 steel, accounting for a soil bearing capacity of 120kn/m2.
This document discusses the design of compression members under uniaxial bending. It notes that columns are rarely under pure axial compression due to eccentricities from rigid frame action or accidental loading. Columns can experience uniaxial or biaxial bending based on the loading. The behavior depends on the relative magnitudes of the bending moment and axial load, which determine the position of the neutral axis. Methods for designing eccentrically loaded short columns include using equations that calculate the neutral axis position and failure mode, or using interaction diagrams that graphically show the safe ranges of moment and axial load.
Footings transfer structural loads from a building to the ground. This document discusses various types of footings and their design procedures. Spread footings are the most common type and are proportioned to have an area large enough that soil and building settlement will be minimized. The general design process involves checking that factored loads are less than the soil's allowable bearing capacity and footing thickness is sufficient to resist punching and beam shear. Reinforcement is calculated and placed to resist bending stresses. Combined and strap footings are also discussed along with their unique design considerations. Brick footings can be used for small residential loads.
1) The document discusses design considerations for columns according to ACI code, including requirements for different types of columns like tied, spirally reinforced, and composite columns.
2) It provides details on failure modes of tied and spiral columns and code requirements for minimum reinforcement ratios, number of bars, clear spacing, cover, and cross sectional dimensions.
3) Lateral reinforcement requirements are discussed, noting ties help restrain longitudinal bars from buckling while spirals provide additional confinement at ultimate load.
This document provides an overview of different seismic analysis methods for reinforced concrete buildings according to Indian code IS 1893-2002, including linear static, nonlinear static, linear dynamic, and nonlinear dynamic analysis. It describes the basic procedures for each analysis type and provides examples of how to calculate design seismic base shear, distribute seismic forces vertically and horizontally, and determine drift and overturning effects. Case studies are presented comparing the results of static and dynamic analysis for regular and irregular multi-storey buildings modeled in SAP2000.
Type of Loads Acting on a Structure/ Buildingsuzain ali
1) The document introduces different types of structures and loads acting on buildings. It discusses load bearing structures and frame structures.
2) Static loads like dead, live, thermal, and settlement loads are important to consider in design. Dead loads include the weight of structural elements while live loads are movable loads.
3) Dynamic loads that change rapidly must also be accounted for. Wind loads can greatly increase due to a structure's design.
4) Load bearing construction uses thick masonry walls to support the entire building but has limitations around seismic performance and construction efficiency.
Backstay Effect Due to Podium Structure InteractionIRJET Journal
- The document discusses the effects of including a below-storey podium structure on a 40-storey building, including increased stiffness and the "backstay effect".
- A podium structure at the base increases the overall stiffness of the building and helps resist lateral loads through load transfer between floors. This is called the "backstay effect".
- The study models and analyzes buildings with and without podium structures to compare their lateral displacement, base shear, time period, storey drift, and degree of shear reversal. Sensitivity analysis is also conducted based on IS 16700 standards.
- The results provide insight into how the inclusion of a podium structure and its height/surface area impact the structural behavior and
The document is an Indian Standard that provides the dimensions, mass, and sectional properties of various hot rolled steel beam, column, channel, and angle sections. It includes tables that list the nominal dimensions, mass, and sectional properties like area, moments of inertia, radii of gyration, etc. of different beam sections classified as Indian Standard medium flange beams.
Rcc design and detailing based on revised seismic codesWij Sangeeta
The document summarizes important provisions of revised seismic codes affecting reinforced concrete (RCC) design and detailing, including:
- Revisions to building configuration definitions, load combinations, and stiffness modifiers.
- Prohibitions on certain structural systems without adequate experimentation/analysis.
- Revisions to design eccentricity, foundation isolation, column/beam sizing and reinforcement, and ductility provisions.
- Updates to standards IS:13920 regarding concrete grade, beam-column joints, lap splices, transverse reinforcement, and special confining reinforcement.
- Queries raised regarding compliance of existing/under construction buildings and clarification needed for irregular geometries.
The document discusses ductile detailing for reinforced concrete structures to make them earthquake resistant. It describes how ductility allows structures to undergo large deformations without collapsing, providing warning before failure. Key aspects of ductile detailing discussed include: avoiding shear and compression failures in beams; confining critical areas of beams and columns; using shear walls to resist lateral loads; and following ductile detailing code IS 13920-1993 for beams, columns, and walls. The document emphasizes the importance of ductile detailing to resist earthquake forces and prevent brittle structural collapse.
The document discusses ductility and ductile detailing in reinforced concrete structures. It states that structures should be designed to have lateral strength, deformability, and ductility to resist earthquakes with limited damage and no collapse. Ductility allows structures to develop their full strength through internal force redistribution. Detailing of reinforcement is important to avoid brittle failure and induce ductile behavior by allowing steel to yield in a controlled manner. Shear walls are also discussed as vertical reinforced concrete elements that help structures resist earthquake loads in a ductile manner.
Progressive Collapse Analysis of RC Framed StructuresAmit Devar
The term progressive collapse defined as the
spread of local damage, from an initiating event, from
element to element resulting, eventually, in the collapse of an
entire structure or a disproportionately large part of it is
known as progressive collapse. The progressive collapse of
structures during severe loading caused by earthquakes,
blasts, and other effects causes catastrophic loss of life. Such
collapse is typically caused by the inability of the structural
system to redistribute its loads following the failure of one or
more structural members to carry gravity loads. In reinforced
concrete (RC) structures, the loss of gravity load carrying
capacity in column.
23-Design of Column Base Plates (Steel Structural Design & Prof. Shehab Mourad)Hossam Shafiq II
This document discusses the design of column base plates to resist both axial loads and bending moments. It provides equations to calculate stresses on the base plate and footing. It then gives an example of designing a base plate for a column supporting an axial load of 1735 kN and bending moment of 200 kN.m. The design process involves calculating eccentricity, base plate dimensions, stresses on the footing, required plate thickness, and checking bending in two directions. The example concludes by specifying a base plate of dimensions 750mm x 500mm x 40mm that satisfies all design requirements.
An eccentric footing consists of two isolated footings connected by a structural strap or lever. This allows the footings to behave as a single unit while transferring both axial and moment loads from columns. Eccentric footings are more economical than combined footings when the soil can support higher pressures and the column spacing is large. They are used when spreading a footing to align load and area centroids is not possible, such as when a column is near a property boundary.
Compression members are structural members subjected to axial compression or compressive forces. Their design is governed by strength and buckling capacity. Columns can fail due to local buckling, squashing, overall flexural buckling, or torsional buckling. Built-up columns use components like lacings, battens, and cover plates to help distribute stress more evenly and increase buckling resistance compared to a single member. Buckling occurs when a straight compression member becomes unstable and bends under a critical load.
This document provides an overview of connections and bracing configurations in structural steel construction. It defines simple connections, which are designed to be flexible, and moment connections, which are designed to be rigid or semi-rigid. Common types of simple and moment connections are described. The document also discusses braced frames, rigid frames, and combination frames that are used for lateral stability. Specific bracing configurations like X, chevron, and eccentric bracing are explained.
COMPARISON OF SEISMIC CODES OF CHINA, INDIA, UK AND USA (STRUCTURAL IRREGULA...shankar kumar
This document compares structural irregularities defined in seismic codes of China, India, the UK, and the USA. It defines seven types of plan irregularities and seven types of vertical/elevation irregularities. It compares how each code defines and quantifies these irregularities using multiplication constants. While the types of irregularities covered are largely consistent between codes, the quantification of irregularities differs through the use of different constant values. The document concludes some irregularities are not addressed in all codes and proposes further study on seismic response of irregular plan structures.
Seismic Analysis of regular & Irregular RCC frame structuresDaanish Zama
This document discusses seismic analysis of regular and irregular reinforced concrete framed buildings. It analyzes 4 building models - a regular 4-story building, a stiffness irregular building with a soft ground story, and two vertically irregular buildings with setbacks on the 3rd floor and 2nd/3rd floors. Static analysis was performed to compare bending moments, shear forces, story drifts, and joint displacements. Results showed irregular buildings experienced higher seismic demands. The regular building performed best, with the single setback building also performing well. Irregular configurations increase seismic effects and should be minimized in design.
This document provides an overview of the design of compression members (columns) in reinforced concrete structures. It discusses various types of columns based on reinforcement, loading conditions, and slenderness ratio. It describes the classification of columns as short or slender. The document also covers effective length, braced vs unbraced columns, codal provisions for reinforcement, and functions of longitudinal and transverse reinforcement. Key points include types of column reinforcement, minimum reinforcement requirements, cover requirements, and assumptions for the limit state of collapse under compression.
This document provides an overview of cold-formed steel sections. It discusses that cold-formed steel sections are manufactured from steel sheets without applying heat through a process like roll forming. The document compares the properties of cold-formed and hot-rolled steel sections, outlines common shapes and applications of cold-formed sections, and describes their behavior under compression and factors like local buckling. It also defines terms related to cold-formed steel and discusses provisions in codes governing their design and use in construction.
This document discusses reinforced concrete shear walls. It provides definitions, design considerations, placement guidelines, and seismic behavior analysis. Shear walls are designed to resist lateral forces from earthquakes by providing strength, stiffness, and minimizing structural sway. Case studies demonstrate that high axial load ratios decrease ductility, and shear walls with staggered openings perform better seismically than those with regular openings.
This document discusses various techniques for retrofitting concrete structures to make them more resistant to seismic activity and other natural hazards. It defines retrofitting as modifying existing structures to increase resistance. Key techniques mentioned include adding new shear walls, steel bracing, column and beam jacketing with steel or concrete, base isolation using seismic isolators, mass reduction by removing floors, and wall thickening. The document also discusses challenges in retrofitting and standards from Indian codes for earthquake-resistant design. The conclusion emphasizes that retrofitting has matured but expertise is still lacking, and optimization is needed to determine the most cost-effective technique for a given structure.
This document discusses pushover analysis, which is an inelastic static analysis method used to evaluate seismic performance of structures. It begins by outlining the target performance levels dictated by codes, then provides an overview of current analysis methods and their limitations. Next, it describes the steps of a pushover analysis in detail, including defining member behavior, applying loads, specifying the load pattern, and incrementally forming plastic hinges. An example application to a 3-story frame structure is presented to demonstrate the process. The document concludes by emphasizing pushover analysis as a practical alternative to time history analysis for estimating seismic response.
Overview of IS 16700:2023 (by priyansh verma)Priyansh
The document discusses the key changes and provisions in the Indian standard IS 16700-2023 for structural safety of tall concrete buildings between 50-250 meters tall. It outlines the standard's scope, definitions of important terms, general requirements for building height, shape, structural systems, loads, structural analysis and modeling considerations, design of structural elements, foundations, and monitoring deformations. The revisions in the new standard include changes to estimating fundamental natural period, considering P-Δ effects in load combinations, including an interstory drift coefficient, and revising requirements for transverse reinforcement in walls.
1. Seismic design involves careful planning, analysis, detailing, and construction to create earthquake-resistant structures.
2. Key steps in planning include making the building symmetrical, avoiding weak stories, selecting good materials, and following code provisions.
3. Design considerations are analyzing structural elements, avoiding weak columns and strong beams, using shear walls and bracing, and designing for increased forces in soft stories. Ductility is increased through design and material choices.
Type of Loads Acting on a Structure/ Buildingsuzain ali
1) The document introduces different types of structures and loads acting on buildings. It discusses load bearing structures and frame structures.
2) Static loads like dead, live, thermal, and settlement loads are important to consider in design. Dead loads include the weight of structural elements while live loads are movable loads.
3) Dynamic loads that change rapidly must also be accounted for. Wind loads can greatly increase due to a structure's design.
4) Load bearing construction uses thick masonry walls to support the entire building but has limitations around seismic performance and construction efficiency.
Backstay Effect Due to Podium Structure InteractionIRJET Journal
- The document discusses the effects of including a below-storey podium structure on a 40-storey building, including increased stiffness and the "backstay effect".
- A podium structure at the base increases the overall stiffness of the building and helps resist lateral loads through load transfer between floors. This is called the "backstay effect".
- The study models and analyzes buildings with and without podium structures to compare their lateral displacement, base shear, time period, storey drift, and degree of shear reversal. Sensitivity analysis is also conducted based on IS 16700 standards.
- The results provide insight into how the inclusion of a podium structure and its height/surface area impact the structural behavior and
The document is an Indian Standard that provides the dimensions, mass, and sectional properties of various hot rolled steel beam, column, channel, and angle sections. It includes tables that list the nominal dimensions, mass, and sectional properties like area, moments of inertia, radii of gyration, etc. of different beam sections classified as Indian Standard medium flange beams.
Rcc design and detailing based on revised seismic codesWij Sangeeta
The document summarizes important provisions of revised seismic codes affecting reinforced concrete (RCC) design and detailing, including:
- Revisions to building configuration definitions, load combinations, and stiffness modifiers.
- Prohibitions on certain structural systems without adequate experimentation/analysis.
- Revisions to design eccentricity, foundation isolation, column/beam sizing and reinforcement, and ductility provisions.
- Updates to standards IS:13920 regarding concrete grade, beam-column joints, lap splices, transverse reinforcement, and special confining reinforcement.
- Queries raised regarding compliance of existing/under construction buildings and clarification needed for irregular geometries.
The document discusses ductile detailing for reinforced concrete structures to make them earthquake resistant. It describes how ductility allows structures to undergo large deformations without collapsing, providing warning before failure. Key aspects of ductile detailing discussed include: avoiding shear and compression failures in beams; confining critical areas of beams and columns; using shear walls to resist lateral loads; and following ductile detailing code IS 13920-1993 for beams, columns, and walls. The document emphasizes the importance of ductile detailing to resist earthquake forces and prevent brittle structural collapse.
The document discusses ductility and ductile detailing in reinforced concrete structures. It states that structures should be designed to have lateral strength, deformability, and ductility to resist earthquakes with limited damage and no collapse. Ductility allows structures to develop their full strength through internal force redistribution. Detailing of reinforcement is important to avoid brittle failure and induce ductile behavior by allowing steel to yield in a controlled manner. Shear walls are also discussed as vertical reinforced concrete elements that help structures resist earthquake loads in a ductile manner.
Progressive Collapse Analysis of RC Framed StructuresAmit Devar
The term progressive collapse defined as the
spread of local damage, from an initiating event, from
element to element resulting, eventually, in the collapse of an
entire structure or a disproportionately large part of it is
known as progressive collapse. The progressive collapse of
structures during severe loading caused by earthquakes,
blasts, and other effects causes catastrophic loss of life. Such
collapse is typically caused by the inability of the structural
system to redistribute its loads following the failure of one or
more structural members to carry gravity loads. In reinforced
concrete (RC) structures, the loss of gravity load carrying
capacity in column.
23-Design of Column Base Plates (Steel Structural Design & Prof. Shehab Mourad)Hossam Shafiq II
This document discusses the design of column base plates to resist both axial loads and bending moments. It provides equations to calculate stresses on the base plate and footing. It then gives an example of designing a base plate for a column supporting an axial load of 1735 kN and bending moment of 200 kN.m. The design process involves calculating eccentricity, base plate dimensions, stresses on the footing, required plate thickness, and checking bending in two directions. The example concludes by specifying a base plate of dimensions 750mm x 500mm x 40mm that satisfies all design requirements.
An eccentric footing consists of two isolated footings connected by a structural strap or lever. This allows the footings to behave as a single unit while transferring both axial and moment loads from columns. Eccentric footings are more economical than combined footings when the soil can support higher pressures and the column spacing is large. They are used when spreading a footing to align load and area centroids is not possible, such as when a column is near a property boundary.
Compression members are structural members subjected to axial compression or compressive forces. Their design is governed by strength and buckling capacity. Columns can fail due to local buckling, squashing, overall flexural buckling, or torsional buckling. Built-up columns use components like lacings, battens, and cover plates to help distribute stress more evenly and increase buckling resistance compared to a single member. Buckling occurs when a straight compression member becomes unstable and bends under a critical load.
This document provides an overview of connections and bracing configurations in structural steel construction. It defines simple connections, which are designed to be flexible, and moment connections, which are designed to be rigid or semi-rigid. Common types of simple and moment connections are described. The document also discusses braced frames, rigid frames, and combination frames that are used for lateral stability. Specific bracing configurations like X, chevron, and eccentric bracing are explained.
COMPARISON OF SEISMIC CODES OF CHINA, INDIA, UK AND USA (STRUCTURAL IRREGULA...shankar kumar
This document compares structural irregularities defined in seismic codes of China, India, the UK, and the USA. It defines seven types of plan irregularities and seven types of vertical/elevation irregularities. It compares how each code defines and quantifies these irregularities using multiplication constants. While the types of irregularities covered are largely consistent between codes, the quantification of irregularities differs through the use of different constant values. The document concludes some irregularities are not addressed in all codes and proposes further study on seismic response of irregular plan structures.
Seismic Analysis of regular & Irregular RCC frame structuresDaanish Zama
This document discusses seismic analysis of regular and irregular reinforced concrete framed buildings. It analyzes 4 building models - a regular 4-story building, a stiffness irregular building with a soft ground story, and two vertically irregular buildings with setbacks on the 3rd floor and 2nd/3rd floors. Static analysis was performed to compare bending moments, shear forces, story drifts, and joint displacements. Results showed irregular buildings experienced higher seismic demands. The regular building performed best, with the single setback building also performing well. Irregular configurations increase seismic effects and should be minimized in design.
This document provides an overview of the design of compression members (columns) in reinforced concrete structures. It discusses various types of columns based on reinforcement, loading conditions, and slenderness ratio. It describes the classification of columns as short or slender. The document also covers effective length, braced vs unbraced columns, codal provisions for reinforcement, and functions of longitudinal and transverse reinforcement. Key points include types of column reinforcement, minimum reinforcement requirements, cover requirements, and assumptions for the limit state of collapse under compression.
This document provides an overview of cold-formed steel sections. It discusses that cold-formed steel sections are manufactured from steel sheets without applying heat through a process like roll forming. The document compares the properties of cold-formed and hot-rolled steel sections, outlines common shapes and applications of cold-formed sections, and describes their behavior under compression and factors like local buckling. It also defines terms related to cold-formed steel and discusses provisions in codes governing their design and use in construction.
This document discusses reinforced concrete shear walls. It provides definitions, design considerations, placement guidelines, and seismic behavior analysis. Shear walls are designed to resist lateral forces from earthquakes by providing strength, stiffness, and minimizing structural sway. Case studies demonstrate that high axial load ratios decrease ductility, and shear walls with staggered openings perform better seismically than those with regular openings.
This document discusses various techniques for retrofitting concrete structures to make them more resistant to seismic activity and other natural hazards. It defines retrofitting as modifying existing structures to increase resistance. Key techniques mentioned include adding new shear walls, steel bracing, column and beam jacketing with steel or concrete, base isolation using seismic isolators, mass reduction by removing floors, and wall thickening. The document also discusses challenges in retrofitting and standards from Indian codes for earthquake-resistant design. The conclusion emphasizes that retrofitting has matured but expertise is still lacking, and optimization is needed to determine the most cost-effective technique for a given structure.
This document discusses pushover analysis, which is an inelastic static analysis method used to evaluate seismic performance of structures. It begins by outlining the target performance levels dictated by codes, then provides an overview of current analysis methods and their limitations. Next, it describes the steps of a pushover analysis in detail, including defining member behavior, applying loads, specifying the load pattern, and incrementally forming plastic hinges. An example application to a 3-story frame structure is presented to demonstrate the process. The document concludes by emphasizing pushover analysis as a practical alternative to time history analysis for estimating seismic response.
Overview of IS 16700:2023 (by priyansh verma)Priyansh
The document discusses the key changes and provisions in the Indian standard IS 16700-2023 for structural safety of tall concrete buildings between 50-250 meters tall. It outlines the standard's scope, definitions of important terms, general requirements for building height, shape, structural systems, loads, structural analysis and modeling considerations, design of structural elements, foundations, and monitoring deformations. The revisions in the new standard include changes to estimating fundamental natural period, considering P-Δ effects in load combinations, including an interstory drift coefficient, and revising requirements for transverse reinforcement in walls.
1. Seismic design involves careful planning, analysis, detailing, and construction to create earthquake-resistant structures.
2. Key steps in planning include making the building symmetrical, avoiding weak stories, selecting good materials, and following code provisions.
3. Design considerations are analyzing structural elements, avoiding weak columns and strong beams, using shear walls and bracing, and designing for increased forces in soft stories. Ductility is increased through design and material choices.
1. Seismic design involves careful planning, analysis, detailing, and construction to create earthquake-resistant structures.
2. Key steps in planning include making the building symmetrical, avoiding weak stories, selecting good materials, and following code provisions.
3. Design considerations are analyzing structural elements, avoiding weak columns and strong beams, using shear walls and bracing, and designing for increased forces in soft stories. Ductility is increased through design and material choices.
1. Seismic design involves careful planning, analysis, detailing, and construction to create earthquake-resistant structures.
2. Key steps in planning include making the building symmetrical, avoiding weak stories, selecting good materials, and following code provisions.
3. Important aspects of design are analyzing structural elements to resist seismic forces, using techniques like shear walls and bracing, and ductile detailing of reinforcement.
4. Careful construction with quality materials and workmanship is also vital for seismic resistance.
Structural design including disaster (wind & cyclone land slide_eq_ resistan...RAJESH JAIN
The document summarizes key aspects of structural design as outlined in Part 6 of the National Building Code of India, with a focus on loads, forces, and earthquake resistance. It discusses the sections and standards covered in Part 6, including loads from wind, seismic activity, imposed loads, and more. Methods of calculating design wind speed and pressure are presented. Seismic zoning maps and factors are shown, along with equations for determining design lateral force based on seismic weight and acceleration spectra. Types of structural irregularities are defined.
Flat slabs were originally invented in the U.S. in 1906 and load tested between 1910-1920. They are reinforced concrete slabs supported by columns without beams. Flat slabs offer advantages like reduced construction costs, faster construction, and greater architectural freedom. They are classified as solid flat slab, solid flat slab with drop panels, solid flat slab with column heads, or banded flat slab. Analysis and design of flat slabs involves distributing moments from equivalent frame analysis to slab components and checking shear and punching resistance.
IRJET- A Research on Comparing the Effect of Seismic Waves on Multistoried Bu...IRJET Journal
The document compares the effect of seismic waves on multistoried buildings with and without shear walls and flanged concrete columns. Three 10-story building models are analyzed using STAAD Pro: Model 1 without seismic resisting structures, Model 2 with concentrically located shear walls along the exterior, and Model 3 with flanged concrete columns along the exterior. Model 2 and 3 experience approximately 10% less lateral force and base shear compared to Model 1. Introducing shear walls or flanged columns improves seismic performance by increasing stiffness and reducing displacements, stresses, and forces in the building. While shear walls provide the greatest stability, flanged columns also enhance seismic resistance and may be more economical for some applications.
Behaviour of Flat Slab by Varying Stiffness in High Seismic ZoneIRJET Journal
This document summarizes a study on analyzing the behavior of flat slab structures with varying stiffness in high seismic zones. Various flat plate and flat slab models with different configurations of shear walls and steel bracings were analyzed using ETABS software for 10, 15, and 20-story buildings. The models were subjected to dead, live, and earthquake loads as per Indian codes. Key parameters like natural period, base shear, storey displacement, and drift were compared. Results show that shear walls are more effective than steel bracings at reducing displacements. Flat slab models with shear walls at the core and periphery performed best with minimum displacement and drift. Increasing the height of buildings leads to higher displacements indicating the need for shear walls
Performance Based Evaluation of Conventional RC Framed Structure Compared wit...IRJET Journal
This document analyzes the seismic performance of an 11-story conventional reinforced concrete (RC) framed structure compared to a flat slab structure. Both linear and nonlinear analysis methods are used to evaluate the structures' performance under seismic loads. The natural period, base shear, story stiffness, and story displacement are calculated and compared for RC and flat slab models with and without shear walls. The results show that the flat slab structure generally has a higher natural period, base shear, and story displacement but lower story stiffness compared to the RC structure. Shear walls are found to significantly increase the stiffness and seismic performance of both structural types.
IRJET-Effective Location Of Shear Walls and Bracings for Multistoried BuildingIRJET Journal
This document analyzes the effectiveness of different structural configurations for resisting lateral loads in a 10-story building subject to seismic activity. Two structural models are considered: a normal building frame and a dual system with shear walls and bracings placed at the building corners. Both models are analyzed using time history analysis in STAAD-Pro. Results show that the dual system experiences significantly less lateral deflection, with displacements reduced by 86-89% compared to the normal frame building. Additionally, the dual system sees only minor reductions in maximum shear force and bending moment compared to the normal frame building. Therefore, the dual system with corner shear walls and bracings provides greatly enhanced seismic performance over a normal framed building.
Effective Location Of Shear Walls and Bracings for Multistoried BuildingIRJET Journal
This document describes a study analyzing the effective placement of shear walls and bracings in a 10-story building to resist seismic forces. Two structural models are developed - a normal building frame and a dual system with shear walls and bracings at the building corners. Both models are analyzed using time history analysis in STAAD-Pro. The results show that the dual system with shear walls and bracings has significantly less lateral deflection under earthquake loading compared to the normal building frame, with deflections reduced by over 70% at the top story. This demonstrates that a combination of shear walls and bracings located at the building corners can greatly enhance the seismic performance of a multi-story building by reducing lateral displacements and
Dynamic Analysis of Steel Moment Resisting Frame on Sloping Ground with Braci...IRJET Journal
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The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
Road construction is not as easy as it seems to be, it includes various steps and it starts with its designing and
structure including the traffic volume consideration. Then base layer is done by bulldozers and levelers and after
base surface coating has to be done. For giving road a smooth surface with flexibility, Asphalt concrete is used.
Asphalt requires an aggregate sub base material layer, and then a base layer to be put into first place. Asphalt road
construction is formulated to support the heavy traffic load and climatic conditions. It is 100% recyclable and
saving non renewable natural resources.
With the advancement of technology, Asphalt technology gives assurance about the good drainage system and with
skid resistance it can be used where safety is necessary such as outsidethe schools.
The largest use of Asphalt is for making asphalt concrete for road surfaces. It is widely used in airports around the
world due to the sturdiness and ability to be repaired quickly, it is widely used for runways dedicated to aircraft
landing and taking off. Asphalt is normally stored and transported at 150’C or 300’F temperature
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represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
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The aim of this manual is to explain the
methodology behind the Levelized Cost of
Hydrogen (LCOH) calculator. Moreover, this
manual also demonstrates how the calculator
can be used for estimating the expenses associated with hydrogen production in Europe
using low-temperature electrolysis considering different sources of electricity
3. a) Design spectra extended up to natural period up of 6 s;
b) Same design response spectra for all buildings,
irrespective of the material of construction (for steel and
concrete);
c) New method for arriving at the approximate natural
period of buildings
d) Response Reduction Factors Revised; Buildings with flat
slabs included;
e) Minimum design lateral force
Changes In Estimation Of The
Hazard
4. f) Load combinations consistent with other
codes;
g) Temporary structures included
h) Importance factor provisions to acknowledge
the density and business continuity;
i) Design Vertical Acceleration Coefficient Av
Changes In Estimation Of The
Hazard
5. II. Changes in Estimation of
Resistance Capacity
j) How to handle different types of irregularity of
structural system;
k) Effect of masonry infill;
l) Use of Cracked Section Properties Ieff
m) Torsional provisions revised;
n) Simplified method for liquefaction potential analysis.
o) Open Ground Storey structures requirements revised
6. BACKDROP
• Code is a consensus document
• Collective wisdom of the drafting group, modified
by larger committee and public comments
• Open to modifications in next revision
• Code need extensive usage for evaluating its ease
of applicability and limitations
7. Design Horizontal Earthquake Force
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 1 2 3 4 5 6
Natural Period T (s)
Sa/g
Type I: Rock or Hard Soil
Type II: Medium Soil
Type III: Soft Soil
Spectral Shape Sa/g
Figure 2: Design Acceleration Coefficient (Sa /g) (corresponding to 5% damping) for use in (a) Equivalent
Static Method, and (b) Response Spectrum Method
a
b
8. Design Horizontal Earthquake Force
5% damping for all structures
– Design force independent of material of
construction
•Steel, RC and Masonry
– Earlier 2% for Steel, 5% for RC, 7% for Masonry
Note: Damping for Wind Conditions different!!!
9. Steel Structures now less punished
• New Code is more attractive for Steel
Structures.
– Damping increase from 2% to 5% and R factor
from 4 to 5. Thus reduction in seismic coefficient
by 1.4*5/4 =1.75 times
11. New Natural Period Empirical Formula for
Shear Wall Buildings
Gives realistic, higher Natural Period for building with walls structures of lesser stiffness
Building ht h 45 m 15 storeys
Building depth d 30m Building Width b 20m
Tx (s) =0.09h/sqrt(d) = 0.74
(equation for non-frame
structures)
Tx (S) =0.1n= 1.5
(not applicable for non-
frame structures)
Wall Thk
(m)
Length
(m) Lwi
Area
(m2)Awi Lwi/h Awi(0.2+Lwi/h)^2
0.3 5 1.5 0.111 0.145
0.25 6 1.5 0.133 0.167
0.3 3 0.9 0.067 0.064
0.25 7 1.75 0.156 0.221
0.25 4 1 0.089 0.083
0.3 3.5 1.05 0.078 0.081
0.3 6.5 1.95 0.144 0.231
SAwi= 9.65 Aw= 0.9929
Tx =0.075h^0.75/sqrt(Aw) = 1.31s
Tx= 1.31s
New Alternative
equation T for wall
structures
As per 7.6.2 c)
Ty=0.09h/sqrt(b) = 0.9s
As per 7.6.2 b)
Ty=0.99s (SAwi=18.3m2, Aw=1.72)
T (s) As per
7.6.2c
As per
7.6.2b
%
walls
( Sawi/
(bxd)
Tx (s) 0.74 1.31 0.71
Ty (s) 0.9 0.99 1.4
As SAwi>2%, equations merge, and
b) will give T less than that from c)
12. Defining Building height h
• h = Height (in m) of building. This excludes the
basement storeys, where basement storey,
walls are connected with the ground floor
deck or fitted between the building columns,
but includes the basement storeys, when they
are not so connected.
h
h
15. Minimum Design Lateral Force
• Min design lateral force ~ 25% of the
applicable Ah in the zone (at PGA)
16. IMPORTANCE FACTOR
• Increased to 1.2 for buildings
>200 persons occupancy.(That’s
buildings with more than 50
apartments)
• Will affect PMAY buildings
which are high density, low
cost
• Ironically low cost housing has
lesser loads (1.5kN/m2 Live
load as vs 2 kN/m2 in non low
cost housing)
19. • Cracked Section Stiffness Properties
• Irregularities
• Code has become more stringent and punitive
for stiffness irregularity
Earthquake- Capacity Side
20. Cracked Section Properties Defined…
• Ieff (cracked) =0.7 Igross for columns and walls
• Ieff (cracked) =0.35 Igross for beams
21. Irregularities
• Torsional Irregularity – Max and min
displacements on floor differ by over 50%
• Torsional Irregularity- First mode is in
torsion
• Plan Stiffness irregularity- Stiffness on
floor below must be more than that on
floor above. (In Tall buildings code –
relaxed to 70%)
• Plan Mass Irregularity- Mass above >1.5
times mass on floor below.
• Plan Weak Storey – Strength less than
floor above.
FLOATING COLUMNS PROHIBITED IN SMRF
23. Diaphragm Flexibility
7.6.4 Diaphragm
• In buildings whose floor diaphragms cannot provide rigid
horizontal diaphragm action in their own plane, design
storey shear shall be distributed to the various vertical
elements of lateral force resisting system considering the
in-plane flexibility of the diaphragms.
• A floor diaphragm shall be considered to be flexible, if it
deforms such that the maximum lateral displacement
measured from the chord of the deformed shape at any
point of the diaphragm is more than 1.2 times the average
displacement of the entire diaphragm (see Fig. 6).
• Usually, reinforced concrete monolithic slab-beam floors
or those consisting of prefabricated or precast elements
with reasonable reinforced screed concrete (at least a
minimum of 50 mm on floors and of 75 mm on roof, with
at least a minimum reinforcement of 6 mm bars spaced at
150 mm centres) as topping, and of plan aspect ratio less
than 3, can be considered to be providing rigid diaphragm
action.
24. Horizontal Irregularity
•Re-entrant Corners
In buildings with re-entrant corners, three-dimensional
dynamic analysis method shall be adopted
•Floor Slabs having Excessive Cut-Outs or Openings
In buildings with discontinuity in their in-plane stiffness, if
the area of the geometric cut-out is,
a) less than or equal to 50 percent, the floor slab shall be
taken as rigid or flexible depending on the location of and
size of openings; and
b) more than 50 percent, the floor slab shall be taken as
flexible
•Buildings with non-parallel lateral force resisting system
shall be analyzed for load
combinations mentioned in 6.3.2.2 or 6.3.4.1.
•In a building with out-of-plane offsets in vertical elements,
following two conditions shall be satisfied, if building is
located in Seismic Zone III, IV or V:
(a) Lateral drift shall be less than 0.2% in the storey having
the offset and in the storeys below; and
(b) Specialist literature shall be referred for removing the
irregularity arising due to out-of-plane offsets in vertical
elements.
26. Vertical Irregularity
i) Stiffness Irregularity (Soft Storey)
A soft storey is a storey whose lateral
stiffness is less than that of the storey above.
The structural plan density (SPD) shall be
estimated when unreinforced masonry infills are
used. When SPD of masonry infills exceeds 20
percent, the effect of URM infills shall be
considered by explicitly modelling the same in
structural analysis (as per 7.9). The design forces
for RC members shall be larger of that obtained
from analysis of:
a) Bare Frame, and
b) Frames with URM Infills,
using 3D modeling of the structure. In buildings
designed considering URM infills, the inter-storey
drift shall be limited to 0.2 percent in the storey
with stiffening and also in all storeys below.
27. Vertical Irregularity
Mass Irregularity
Mass irregularity shall be considered to exist,
when the seismic weight (as per 7.7) of any
floor is more than 150 percent of that of the
floors below.
In buildings with mass irregularity and located
in Seismic Zones III, IV and V, the earthquake
effects shall be estimated by Dynamic Analysis
Method (as per 7.7).
Vertical Geometric Irregularity
Vertical geometric irregularity shall be
considered to exist, when the horizontal
dimension of the lateral force resisting system
in any storey is more than 125 percent of the
storey below.
In buildings with vertical geometric irregularity
and located in Seismic Zones III, IV and V, the
earthquake effects shall be estimated by
Dynamic Analysis Method (as per 7.7).
28. Vertical Irregularity
In-Plane Discontinuity in Vertical Elements
Resisting Lateral Force
In-plane discontinuity in vertical elements
which are resisting lateral force shall be
considered to exist, when in-plane offset of the
lateral force resisting elements is greater than
20 percent of the plan length of those
elements, …. in Seismic Zones III, IV and V,
buildings with in-plane discontinuity shall not
be permitted.
v) Strength Irregularity (Weak Storey)
A weak storey is a storey whose lateral
strength is less than that of the storey above.
In such a case, buildings in Seismic Zones III, IV
and V shall be designed such that safety of the
building is not jeopardized; also, provisions of
7.10 shall be followed
29. How much wall area in Shear Wall
Structures ?
Country Wall Density (Total) Min in each
direction
Kyrgyzstan 15% 6.5%
Turkey 4-12% 2-6%
Chile 3-6% 1.5-3%
Romania 12-14% 6-7%
Colombia 3-5% 1.5%
India 1-4%? 0.5-3%?
Min 1.5%-2% in each direction is desirable for Zones IV and V
30. Ref: CONCRETE SHEAR WALL CONSTRUCTION
M. Ofelia Moroni, University of Chile, Santiago, Chile (eeri.org)
Chile Romania
Typical Layouts…
31. When to consider URM panels in
analysis and design?
• Structural Plan Density of unreinforced
masonry infill walls > 20%, URM walls to be
considered in design
• Not usually the case!!!
Golcuk, 2000
34. RC Frame Buildings with Open Storeys
In such buildings measures shall be adopted, which increase
both stiffness and strength like:
a) RC structural walls, or b) Braced frames, in select bays
When the RC structural walls are provided, they shall:
a) Be founded on properly designed foundations;
b) Be continuous preferably over full height of building; and
c) Be connected preferably to the moment resisting frame of
building.
d) Not cause additional torsional irregularity in plan than already
present
35. RC Frame Buildings with Open Storeys
e) Lateral stiffness in the open storey(s) >80 percent of that in the
storey above; and
f) Lateral strength in the open storey(s) > 90 percent of that in the
storey above.
g) Have at least 2 percent (SPD) along each principal direction in
Seismic Zones III, IV and V and well distributed in the plan of
the building along each direction.
36. IS:13920 – 2016
•Major Changes
– Scope
•Ductile Design and Detailing of RC Structures
– Collapse Mechanism
•Column-Beam Strength Ratio b
– Shear Design of Beam-Column Joints
•Minimum Column Size Max[300 mm; 20db]
– Flexural Strength of Structural Walls
•Principle of Superposition
– Mechanical Couplers
38. 1.1.3 All RC frames, RC walls and their
elements in a structure need not be designed to
resist lateral loads and the designer can
judiciously identify the lateral load resisting
system based on relative stiffness and location
in the building and design those members for
full lateral force.
39. How to identify LRFS
• Select only those frames or shear walls as part of
LFRS (in a direction) which participate
significantly (Base Shear distribution is a good
indicator for this).
• Identify what % (x) of lateral load these frames
these together carry (Should be in range of
90%+).
• Scale lateral force by 100/x - to ensure the
selected system is capable of carrying at least
100% of force in considered direction
42. Also….
• 1.1.3 …….RC monolithic members assumed
not to participate in the lateral force resisting
system (see 3.7) shall be permitted provided
that their effect on the seismic response of
the system is accounted for. Consequence of
failure of structural and non-structural
members not part of the lateral force resisting
system shall also be considered in design.
43. Gravity Columns…
• Design gravity columns as per Section 11.
– Gravity columns in buildings shall be detailed
according to 11.1 and 11.2 for bending moments
induced when subjected to “R” times the design
lateral displacement under the factored
equivalent static design seismic loads given by IS
1893 (Part 1).
44. HOW TO….
• Run the model for R times lateral loads
and check gravity columns for these
bending moments. Its almost always still
an insignificant stress ratio and more
economical to design for, than providing
ductile detailing.
45. What’s not new but has
been ignored all
along…
5.1 The design and construction of reinforced
concrete buildings shall be governed by
provisions of IS 456, except as modified by the
provisions of this standard for those elements
participating in lateral force resistance.
47. WALLS or COLUMN?
• WHAT THIS MEANS
– Any member that is desired to be defined as a wall
as per IS 456 may not have axial stress ratio
greater than say 0.28fck
– that is to say it cannot be governed by min
reinforcement of rv =0.12% and rh=0.2% if the
above axial stress ratio is exceeded
– In such a case all requirements of Columns as per
IS 456 are applicable (min rv =0.8% ….)???
48. Beam Width
For the first time, explicitly acknowledged that beam
may be wider than column as long as transverse
reinforcement in continued into beam column joint.
Great relief for some situations and to ease congestion
in beam-column joint.
49. Mechanical Couplers
• Use of mechanical couplers
allows for modular and
mechanised construction-
• Lapping bars anywhere and
all together
50. Min Link Diameter
• Link min dia for beams and columns to be 8
mm.
• Encouraging better shear capacity
• Acknowledging the corrosion effect on shear
capacity of members
51. Columns
Probably the most important change in the
code
• The factored axial compressive stress
considering all load combinations relating
to seismic loads shall be limited to 0.40 fck
in all such members, except in those
covered under 10.
• This will perforce require larger sectional
size of column or use of higher mix of
concrete!
52. Limiting Column Axial Stress Ratio
• Lesser axial stress ratio will result in lesser
percentage reinforcement demand even in
case of higher bending stress and will improve
column behaviour.
• Special Confining reinforcement- Max spacing
of links = 100mm
53. Ensuring Development of Beam
Reinforcement
• Min dimension of
column =20 db, db = max
beam bar dia for exterior
columns
• E.g. Beam Bar dia=20,
Column Size=400
54. Stress on Collapse Mechanism
• All damage in one storey
Distributed damage in
all storeys
55. SHEAR WALLS
• MIN thickness =300 for coupled walls to avoid
congestion due to coupling beam steel.
• Special Shear walls must be founded on
foundations- i.e. floating special shear walls
are not allowed!!!
57. Shear Wall Boundary Elements
Much relief in Boundary Elements design. More
relaxed than SMRF columns
For columns
58. Shear Wall Boundary Elements
Much relief in Boundary Elements design. More
relaxed than SMRF columns
For columns
sv 100 mm
h 160 mm
fck 30 N/mm2
fy 500 N/mm2
Ag 2800 cm2 40x70
Ak 1800 cm2 30x60
Ash 96 mm
48 mm
For walls
boundary
elements
1
2
2
1
59. Gravity Columns confinement and
shear capacity requirements
• 11.1 The provisions in 11.1.1 and 11.1.2 shall be satisfied, when
induced bending moments and horizontal shear forces under the
said lateral displacement combined with factored gravity bending
moment and shear force do not exceed the design moment of
resistance and design lateral shear capacity of the column.
– 11.1.1 Gravity columns shall satisfy 7.3.2, 7.4.1 and 7.4.2. But, spacing
of links along the full column height shall not exceed 6 times diameter
of smallest longitudinal bar or 150 mm.
– 11.1.2 Gravity columns with factored gravity axial stress exceeding
0.4fck shall satisfy 11.1.1 and shall have transverse reinforcement at
least one half of special confining reinforcement required by 8.