Prestressed concrete beams can be damaged by overloading beyond cracking stage leading to the reduction of flexural rigidity and excessive deflection. The progressive of damage, crack and permanent deflection can be occurred at the high level of load after cracking. Structural performance of damaged girder can be recovered and improved by external post tension. The level of external prestressing force required in strengthening depends directly on the level of damage due to overloading. This research studied the effect of levels of damage on flexural rigidity, crack and deflection of the test girder. Three levels of damage can be expressed in terms of 0.65, 0.75 and 0.85 times the predicted ultimate load of the test beam. Three levels of external prestressing forces (2, 2.5 and 3 times of the internal prestressing force applied in undamaged reference beam) are applied in strengthening at each level of damage. The results show that reduced flexural rigidity, increased permanent deformation and crack width due to overloading can be recovered by external post tension. Strengthening by means of external post tension can be effectively applied to the damaged beam at the level of damage not more than 0.65 times of predicted ultimate load.
Vibration analysis of lathe structrure due to gear defect using fem 02THANMAY JS
The document discusses vibration analysis of lathe structures due to gear defects using finite element modeling. It aims to analyze the effects of unbalanced forces generated by machine elements like spindles and gears on the lathe structure. Both frequency domain and time domain analyses will be conducted using FEM. Experiments will also be conducted to measure vibration velocities on critical points of a lathe for different spindle speeds using a vibration tester. The results of experimental and theoretical analyses will be discussed to monitor machine elements and understand the effects of vibration on the lathe structure.
This document discusses the 3-point flexural test, which measures the flexural properties of materials. In a 3-point flexural test, a specimen is placed on two supporting pins and a loading pin is applied in the middle. Calculations are performed to determine flexural stress, strain, and modulus based on the load and deflection measurements. The test provides values for modulus of elasticity in bending, flexural stress, flexural strain, and flexural stress-strain response. It is a common test for evaluating a material's stiffness when flexed.
This document discusses various modes of failure for components in industrial power transmission gear drives, including gears, shafts, bearings, and seals. It describes different types of gear failures such as surface fatigue (pitting), wear, plastic flow, and breakage. Pitting is subdivided into initial, destructive, and normal pitting. The document explains the causes and appearances of each failure mode with diagrams and photos. It aims to help identify the causes of problems in gear drives and indicate potential remedies.
The document discusses a presentation on a universal testing machine. It describes how the machine is used to apply tensile, compressive, and shear forces to test materials and measure their properties. It explains that the machine uses load cells, crossheads, and columns to grip specimens and apply and measure forces. The document outlines the working principle of the machine and procedures for tensile and compression tests.
This document discusses residual stresses, which are stresses that remain in a solid material after the original cause of stress is removed. Residual stresses can be desirable or undesirable. Common sources of residual stresses include casting, welding, machining, heat treatment, and plastic deformation during bending, rolling, and forging. Two methods for imparting beneficial compressive residual stresses are laser peening and shot peening. Various techniques for measuring residual stresses are also outlined such as X-ray diffraction, ultrasonic methods, and the hole drilling strain gage technique.
Design against fluctuating loads, stress concentration, Goodman and Modified Goodman Diagrams, Factors affecting stress concentration, Use of charts for finding stress concentration facotrs
Structural analysis of multiplate clutchIOSR Journals
Clutch is mechanism which transfers the rotary motion of one shaft to the other shaft when desired. In automobiles friction clutches are widely used in power transmission applications. To transmit maximum torque in friction clutches selection of the friction material is one of the important task. In this paper, the multi plate clutch is designed by using uniform wear theory. The 3D model of multi plate clutch has been prepared using modeling software Pro/E. The structural analysis is carried out for friction plate by using analysis software Ansys Workbench 14.0. The results for stress, strain, total deformation and for strain energy are obtained. These results are compared for two different friction materials viz. cork and SF001
The document proposes the design and development of a universal testing machine with a load capacity of 0.3kN. The applicants, Aashish Kholiya and Ravi Teja, are undergraduate students at IIT Ropar who are undertaking this project under the guidance of Dr. Dhiraj Mahajan. They plan to design components like the ball screw, base plate, select appropriate sensors and a stepper motor. Their objectives are to develop a low-cost machine with high accuracy. They have conducted preliminary work on component design and sensor selection. A work plan with timeline is also provided to complete the project in 6 months. If approved, the project will be executed at IIT Ropar.
Vibration analysis of lathe structrure due to gear defect using fem 02THANMAY JS
The document discusses vibration analysis of lathe structures due to gear defects using finite element modeling. It aims to analyze the effects of unbalanced forces generated by machine elements like spindles and gears on the lathe structure. Both frequency domain and time domain analyses will be conducted using FEM. Experiments will also be conducted to measure vibration velocities on critical points of a lathe for different spindle speeds using a vibration tester. The results of experimental and theoretical analyses will be discussed to monitor machine elements and understand the effects of vibration on the lathe structure.
This document discusses the 3-point flexural test, which measures the flexural properties of materials. In a 3-point flexural test, a specimen is placed on two supporting pins and a loading pin is applied in the middle. Calculations are performed to determine flexural stress, strain, and modulus based on the load and deflection measurements. The test provides values for modulus of elasticity in bending, flexural stress, flexural strain, and flexural stress-strain response. It is a common test for evaluating a material's stiffness when flexed.
This document discusses various modes of failure for components in industrial power transmission gear drives, including gears, shafts, bearings, and seals. It describes different types of gear failures such as surface fatigue (pitting), wear, plastic flow, and breakage. Pitting is subdivided into initial, destructive, and normal pitting. The document explains the causes and appearances of each failure mode with diagrams and photos. It aims to help identify the causes of problems in gear drives and indicate potential remedies.
The document discusses a presentation on a universal testing machine. It describes how the machine is used to apply tensile, compressive, and shear forces to test materials and measure their properties. It explains that the machine uses load cells, crossheads, and columns to grip specimens and apply and measure forces. The document outlines the working principle of the machine and procedures for tensile and compression tests.
This document discusses residual stresses, which are stresses that remain in a solid material after the original cause of stress is removed. Residual stresses can be desirable or undesirable. Common sources of residual stresses include casting, welding, machining, heat treatment, and plastic deformation during bending, rolling, and forging. Two methods for imparting beneficial compressive residual stresses are laser peening and shot peening. Various techniques for measuring residual stresses are also outlined such as X-ray diffraction, ultrasonic methods, and the hole drilling strain gage technique.
Design against fluctuating loads, stress concentration, Goodman and Modified Goodman Diagrams, Factors affecting stress concentration, Use of charts for finding stress concentration facotrs
Structural analysis of multiplate clutchIOSR Journals
Clutch is mechanism which transfers the rotary motion of one shaft to the other shaft when desired. In automobiles friction clutches are widely used in power transmission applications. To transmit maximum torque in friction clutches selection of the friction material is one of the important task. In this paper, the multi plate clutch is designed by using uniform wear theory. The 3D model of multi plate clutch has been prepared using modeling software Pro/E. The structural analysis is carried out for friction plate by using analysis software Ansys Workbench 14.0. The results for stress, strain, total deformation and for strain energy are obtained. These results are compared for two different friction materials viz. cork and SF001
The document proposes the design and development of a universal testing machine with a load capacity of 0.3kN. The applicants, Aashish Kholiya and Ravi Teja, are undergraduate students at IIT Ropar who are undertaking this project under the guidance of Dr. Dhiraj Mahajan. They plan to design components like the ball screw, base plate, select appropriate sensors and a stepper motor. Their objectives are to develop a low-cost machine with high accuracy. They have conducted preliminary work on component design and sensor selection. A work plan with timeline is also provided to complete the project in 6 months. If approved, the project will be executed at IIT Ropar.
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to fluctuating stresses that are less than the static yield strength of the material. It accounts for about 90% of industrial failures. Fatigue occurs in five stages: cyclic plastic deformation, crack initiation, crack propagation, propagation of macro cracks, and final fracture. It is characterized by beach marks and a rough, brittle fracture surface. Fatigue life can be represented using an S-N curve which plots the maximum stress versus the number of cycles to failure. The fatigue limit or endurance limit is identified as the stress below which a material can undergo any number of stress cycles without failure.
Given:
Stresses:
i) 350 N/mm2 for 85% of time
ii) 500 N/mm2 for 3% of time
iii) 400 N/mm2 for 12% of remaining time
Material: Plain carbon steel 50C
Using Miner's rule:
For stress i)
N1/Nf1 = 0.85
Where, N1 is no. of cycles component can withstand at stress 350 N/mm2
Nf1 is no. of cycles to failure at stress 350 N/mm2
Similarly, for other stresses:
N2/Nf2 = 0.03
N3/Nf3 = 0.12
Equ
The document discusses types of stresses that occur in materials, including tension/compression stress, shear stress, and torsion stress. It also discusses residual stress, which remains in a structure after manufacturing processes that involve mechanical or thermal effects. Residual stress can cause distortion in components and premature failure. Common manufacturing techniques like shot peening and surface grinding induce compressive residual stresses that increase fatigue strength, while chrome plating induces tensile residual stresses that decrease fatigue strength.
The document discusses an Instron machine, which is a versatile instrument used to measure load from 2 grams to 100 kgs using a strain gauge principle. It consists of a load cell containing metal beams with strain gauges that measure the resistance change when a load is applied. This allows the machine to generate a load-elongation curve on a chart. The Instron machine can test properties of yarns, cords, fibers and other materials under tension, and has applications in measuring tensile, flexural, friction and tear properties. It operates over a wide range of speeds and loads with interchangeable load cells and grips.
Torsional Fatigue Performance of Induction Hardened 1045 and 10V45 SteelsFluxtrol Inc.
Microalloying of medium carbon bar steels is a common
practice for a number of traditional components; however, use
of vanadium microalloyed steels is expanding into
applications beyond their original designed use as controlled
cooled forged and hot rolled products and into heat treated
components. As a result, there is uncertainty regarding the
influence of vanadium on the properties of heat treated
components, specifically the effect of rapid heat treating such
as induction hardening. In the current study, the torsional
fatigue behavior of hot rolled and scan induction hardened
1045 and 10V45 bars are examined and evaluated at effective
case depths of 25, 32, and 44% of the radius. Torsional fatigue
tests were conducted at a stress ratio of 0.1 and shear stress
amplitudes of 550, 600, and 650 MPa. Cycles to failure are
compared to an empirical model, which accounts for case
depth as well as carbon content.
Experiment NO:6 describes a compression test performed on an anisotropic wooden material to determine its compressive strength when force is applied both parallel and perpendicular to its fibers. When force was applied perpendicular to the fibers, the wooden block failed at a compressive strength of 4.7712x107 N/m2. When applied parallel to the fibers, the failure strength was lower at 1.204x107 N/m2. Detailed load-deformation data is provided in tables showing that the material can withstand over 10 times more load when compressed parallel rather than perpendicular to its fibers, as the fibers act like columns parallel to the load.
Fatigue Analysis of Structures (Aerospace Application)Mahdi Damghani
This document provides an introduction to fatigue analysis of aerospace structures. It discusses key topics including stress-life analysis methods, S-N curves, stress concentration factors, notch sensitivity, and fatigue failure locations. Examples of fatigue critical locations in aircraft components like flaps, struts, and baffle panels are also shown. The document concludes with examples calculating stresses, stress ratios, and fatigue life based on the stress-life approach.
Microstructural and Torsional Fatigue Characteristics of Singleshot and Scan ...Fluxtrol Inc.
Scan and single-shot induction hardening were used to harden 1045 and 10V45 steels. Torsional fatigue testing found that while case hardness was higher in 10V45, 1045 exhibited greater ductility during crack propagation, leading to improved fatigue life. Scan hardening produced a finer prior austenite grain size and lower residual stresses than single-shot hardening. However, fatigue performance was similar between the two processes at 550 MPa stress amplitude, with single-shot showing 70% higher life at 650 MPa.
A universal testing machine is used to perform tensile, compressive, and shear strength tests on materials and structures. It consists of a loading unit, control panel, and control devices. The document outlines the components, working principle, and procedures for conducting compressive, tensile, and shear tests using a universal testing machine. Specimens are gripped firmly and loaded incrementally until the yield point is reached, then the maximum load is recorded to determine the material's strength. Proper specimen dimensions and a uniform loading rate without jerks are important to get accurate test results.
This document provides definitions and concepts related to machine elements design. It covers topics such as factor of safety, endurance limit, impact loads, design process phases, types of loads/stresses, factors affecting endurance strength, types of fractures, spring types and properties, joints, keys, couplings, screws, welds and failures. It contains questions and answers on these topics across 4 units - stresses and strains, shafts, fasteners and joints, and springs.
Tensile, Impact and Hardness Testing of Mild SteelGulfam Hussain
The main purpose of this report is to study the mechanical properties and
failure mode of mild steel. Three types of standard tests i.e. tensile test, impact
test, and hardness test were conducted on the standard specimens of mild steel.
From the tests, results were obtained; Tensile strength, Impact strength, and
hardness were calculated. It was observed that Tensile Strength, Impact Strength
and Hardness of MS specimen were 1450.833 N/mm², 29.5 J & 59.25 HRB.
This document presents a pre-project presentation on measuring residual stress distribution and fatigue life assessment of butt-welded joints. The project aims to experimentally investigate residual stresses in butt welds before and after shot peening, and estimate fatigue life. Literature on welding residual stresses and shot peening was reviewed. Experimental methods will include X-ray diffraction to measure residual stresses and fatigue testing. Work completed includes material selection, welding, and initial residual stress measurements. Remaining work is fatigue testing, hardness testing, and analyzing the effect of shot peening on fatigue life. The project will be conducted over 16 weeks at BNMIT and other collaborating institutions.
This document provides an overview of fatigue failure. It begins by defining fatigue as the premature failure or lowering of strength of a material due to repetitive stresses, even if they are below the material's yield strength. It then discusses key topics in fatigue such as stress cycles, S-N curves, fatigue testing, and factors that affect fatigue life. Crack initiation and propagation stages are described. Methods for improving fatigue performance, such as shot peening and removing stress concentrators, are also covered.
Testing mechanical properties of textile compositesfaizanali353
This document outlines various mechanical tests conducted on textile composites, including Brinell hardness testing, tensile strength testing, compressive strength testing, fracture toughness testing, and fatigue testing. Brinell hardness testing involves applying a load to a steel ball pressed into the material surface. Tensile strength testing uses a universal tester to pull specimens until failure. Compressive strength testing employs a combined loading fixture according to ASTM standards. Fracture toughness is evaluated using mixed-mode bending. Fatigue testing cyclically loads materials to induce cracking and failure over time. Standard test methods and procedures are described for each technique.
This document discusses fatigue resistance testing. It defines fatigue as failure that occurs in structures subjected to fluctuating stresses over time, usually from repeated stress cycling that causes crack initiation and propagation. There are three types of cyclic stresses: reversed, repeated, and random. Fatigue resistance testing involves subjecting test specimens to these different stress cycles to determine their fatigue life. Two common fatigue testing machines are described: rotating bending and axial loading types. An example fatigue test on LDPE is also mentioned.
1. The beam is a cantilever 1.2 m long made of steel tube with an external diameter of 6 cm and internal diameter of 5 cm.
2. A concentrated load W is applied at the free end of the cantilever beam.
3. The maximum bending stress in the beam is not to exceed 1. The value of the load W that satisfies this condition is required.
Fatigue testing involves subjecting materials to repetitive loads or stresses to determine their fatigue life. There are two main types of fatigue testing: constant amplitude testing, where the stress level remains constant for each cycle, and variable amplitude testing, where the stress level varies each cycle. Fatigue testing can be done on standardized test specimens or actual components. Common machines used include rotating beam machines, where a stationary load bends a rotating specimen, creating repeated stresses. The results of fatigue testing are often displayed using an S-N curve to show the relationship between stress levels and the number of cycles before failure.
This document discusses bending stresses in beams. It begins by defining key terms like deflection curve, plane of bending, and curvature. It then discusses the types of bending (pure and non-uniform), and how longitudinal strains in beams vary linearly with the distance from the neutral axis. An example calculation is provided to determine radius of curvature, curvature, and midpoint deflection given longitudinal strain. The document concludes by stating that for linear elastic materials, normal stress varies linearly with distance from the neutral axis, and two equilibrium equations must be satisfied since only a bending moment acts on the cross section.
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to fluctuating stresses that are less than the static yield strength of the material. It accounts for about 90% of industrial failures. Fatigue occurs in five stages: cyclic plastic deformation, crack initiation, crack propagation, propagation of macro cracks, and final fracture. It is characterized by beach marks and a rough, brittle fracture surface. Fatigue life can be represented using an S-N curve which plots the maximum stress versus the number of cycles to failure. The fatigue limit or endurance limit is identified as the stress below which a material can undergo any number of stress cycles without failure.
Given:
Stresses:
i) 350 N/mm2 for 85% of time
ii) 500 N/mm2 for 3% of time
iii) 400 N/mm2 for 12% of remaining time
Material: Plain carbon steel 50C
Using Miner's rule:
For stress i)
N1/Nf1 = 0.85
Where, N1 is no. of cycles component can withstand at stress 350 N/mm2
Nf1 is no. of cycles to failure at stress 350 N/mm2
Similarly, for other stresses:
N2/Nf2 = 0.03
N3/Nf3 = 0.12
Equ
The document discusses types of stresses that occur in materials, including tension/compression stress, shear stress, and torsion stress. It also discusses residual stress, which remains in a structure after manufacturing processes that involve mechanical or thermal effects. Residual stress can cause distortion in components and premature failure. Common manufacturing techniques like shot peening and surface grinding induce compressive residual stresses that increase fatigue strength, while chrome plating induces tensile residual stresses that decrease fatigue strength.
The document discusses an Instron machine, which is a versatile instrument used to measure load from 2 grams to 100 kgs using a strain gauge principle. It consists of a load cell containing metal beams with strain gauges that measure the resistance change when a load is applied. This allows the machine to generate a load-elongation curve on a chart. The Instron machine can test properties of yarns, cords, fibers and other materials under tension, and has applications in measuring tensile, flexural, friction and tear properties. It operates over a wide range of speeds and loads with interchangeable load cells and grips.
Torsional Fatigue Performance of Induction Hardened 1045 and 10V45 SteelsFluxtrol Inc.
Microalloying of medium carbon bar steels is a common
practice for a number of traditional components; however, use
of vanadium microalloyed steels is expanding into
applications beyond their original designed use as controlled
cooled forged and hot rolled products and into heat treated
components. As a result, there is uncertainty regarding the
influence of vanadium on the properties of heat treated
components, specifically the effect of rapid heat treating such
as induction hardening. In the current study, the torsional
fatigue behavior of hot rolled and scan induction hardened
1045 and 10V45 bars are examined and evaluated at effective
case depths of 25, 32, and 44% of the radius. Torsional fatigue
tests were conducted at a stress ratio of 0.1 and shear stress
amplitudes of 550, 600, and 650 MPa. Cycles to failure are
compared to an empirical model, which accounts for case
depth as well as carbon content.
Experiment NO:6 describes a compression test performed on an anisotropic wooden material to determine its compressive strength when force is applied both parallel and perpendicular to its fibers. When force was applied perpendicular to the fibers, the wooden block failed at a compressive strength of 4.7712x107 N/m2. When applied parallel to the fibers, the failure strength was lower at 1.204x107 N/m2. Detailed load-deformation data is provided in tables showing that the material can withstand over 10 times more load when compressed parallel rather than perpendicular to its fibers, as the fibers act like columns parallel to the load.
Fatigue Analysis of Structures (Aerospace Application)Mahdi Damghani
This document provides an introduction to fatigue analysis of aerospace structures. It discusses key topics including stress-life analysis methods, S-N curves, stress concentration factors, notch sensitivity, and fatigue failure locations. Examples of fatigue critical locations in aircraft components like flaps, struts, and baffle panels are also shown. The document concludes with examples calculating stresses, stress ratios, and fatigue life based on the stress-life approach.
Microstructural and Torsional Fatigue Characteristics of Singleshot and Scan ...Fluxtrol Inc.
Scan and single-shot induction hardening were used to harden 1045 and 10V45 steels. Torsional fatigue testing found that while case hardness was higher in 10V45, 1045 exhibited greater ductility during crack propagation, leading to improved fatigue life. Scan hardening produced a finer prior austenite grain size and lower residual stresses than single-shot hardening. However, fatigue performance was similar between the two processes at 550 MPa stress amplitude, with single-shot showing 70% higher life at 650 MPa.
A universal testing machine is used to perform tensile, compressive, and shear strength tests on materials and structures. It consists of a loading unit, control panel, and control devices. The document outlines the components, working principle, and procedures for conducting compressive, tensile, and shear tests using a universal testing machine. Specimens are gripped firmly and loaded incrementally until the yield point is reached, then the maximum load is recorded to determine the material's strength. Proper specimen dimensions and a uniform loading rate without jerks are important to get accurate test results.
This document provides definitions and concepts related to machine elements design. It covers topics such as factor of safety, endurance limit, impact loads, design process phases, types of loads/stresses, factors affecting endurance strength, types of fractures, spring types and properties, joints, keys, couplings, screws, welds and failures. It contains questions and answers on these topics across 4 units - stresses and strains, shafts, fasteners and joints, and springs.
Tensile, Impact and Hardness Testing of Mild SteelGulfam Hussain
The main purpose of this report is to study the mechanical properties and
failure mode of mild steel. Three types of standard tests i.e. tensile test, impact
test, and hardness test were conducted on the standard specimens of mild steel.
From the tests, results were obtained; Tensile strength, Impact strength, and
hardness were calculated. It was observed that Tensile Strength, Impact Strength
and Hardness of MS specimen were 1450.833 N/mm², 29.5 J & 59.25 HRB.
This document presents a pre-project presentation on measuring residual stress distribution and fatigue life assessment of butt-welded joints. The project aims to experimentally investigate residual stresses in butt welds before and after shot peening, and estimate fatigue life. Literature on welding residual stresses and shot peening was reviewed. Experimental methods will include X-ray diffraction to measure residual stresses and fatigue testing. Work completed includes material selection, welding, and initial residual stress measurements. Remaining work is fatigue testing, hardness testing, and analyzing the effect of shot peening on fatigue life. The project will be conducted over 16 weeks at BNMIT and other collaborating institutions.
This document provides an overview of fatigue failure. It begins by defining fatigue as the premature failure or lowering of strength of a material due to repetitive stresses, even if they are below the material's yield strength. It then discusses key topics in fatigue such as stress cycles, S-N curves, fatigue testing, and factors that affect fatigue life. Crack initiation and propagation stages are described. Methods for improving fatigue performance, such as shot peening and removing stress concentrators, are also covered.
Testing mechanical properties of textile compositesfaizanali353
This document outlines various mechanical tests conducted on textile composites, including Brinell hardness testing, tensile strength testing, compressive strength testing, fracture toughness testing, and fatigue testing. Brinell hardness testing involves applying a load to a steel ball pressed into the material surface. Tensile strength testing uses a universal tester to pull specimens until failure. Compressive strength testing employs a combined loading fixture according to ASTM standards. Fracture toughness is evaluated using mixed-mode bending. Fatigue testing cyclically loads materials to induce cracking and failure over time. Standard test methods and procedures are described for each technique.
This document discusses fatigue resistance testing. It defines fatigue as failure that occurs in structures subjected to fluctuating stresses over time, usually from repeated stress cycling that causes crack initiation and propagation. There are three types of cyclic stresses: reversed, repeated, and random. Fatigue resistance testing involves subjecting test specimens to these different stress cycles to determine their fatigue life. Two common fatigue testing machines are described: rotating bending and axial loading types. An example fatigue test on LDPE is also mentioned.
1. The beam is a cantilever 1.2 m long made of steel tube with an external diameter of 6 cm and internal diameter of 5 cm.
2. A concentrated load W is applied at the free end of the cantilever beam.
3. The maximum bending stress in the beam is not to exceed 1. The value of the load W that satisfies this condition is required.
Fatigue testing involves subjecting materials to repetitive loads or stresses to determine their fatigue life. There are two main types of fatigue testing: constant amplitude testing, where the stress level remains constant for each cycle, and variable amplitude testing, where the stress level varies each cycle. Fatigue testing can be done on standardized test specimens or actual components. Common machines used include rotating beam machines, where a stationary load bends a rotating specimen, creating repeated stresses. The results of fatigue testing are often displayed using an S-N curve to show the relationship between stress levels and the number of cycles before failure.
This document discusses bending stresses in beams. It begins by defining key terms like deflection curve, plane of bending, and curvature. It then discusses the types of bending (pure and non-uniform), and how longitudinal strains in beams vary linearly with the distance from the neutral axis. An example calculation is provided to determine radius of curvature, curvature, and midpoint deflection given longitudinal strain. The document concludes by stating that for linear elastic materials, normal stress varies linearly with distance from the neutral axis, and two equilibrium equations must be satisfied since only a bending moment acts on the cross section.
Final Year Project Presentation (June 2015) : INVESTIGATION OF SHEAR BEHAVIOU...Asadullah Malik
It was a 20 min presentation made to participate in the Rector's Gold Medal Competition for the best undergrad project, in which our research based project won 2nd position.
This document discusses prestressed and post-tensioned concrete. It covers topics like pretensioning and post-tensioning, stages of loading, partial prestressing, steel wires, strands and bars, fibre glass tendons, grouting, end anchorages, tensioning methods, post-tensioning systems using hydraulic jacks, bonded and unbonded systems, wedge action anchorages, time-dependent losses from creep, shrinkage, steel relaxation, anchorage, bending, friction, and tendon elongation. The document is split into two modules, with the second module focusing more on end anchorages and post-tensioning systems.
This document defines and describes various types and concepts related to prestressed concrete. It discusses:
1) Definitions of prestressing steel types like wires, strands, tendons, and cables. It also defines bonded and unbonded tendons.
2) Advantages of prestressing like increased strength, reduced cracking, and suitability for precast construction.
3) Limitations include needing skilled technology and higher material costs.
4) Types of prestressing based on force source, location, sequence, member shape, and direction. It provides examples of pre-tensioning and post-tensioning, internal and external prestressing, and linear and circular prestressing.
1. Pre-stressed concrete uses steel tendons that are tensioned before or after the concrete is poured to put the concrete in compression and improve its strength.
2. There are two main types: pre-tensioned concrete, where tendons are tensioned before the concrete is poured, and post-tensioned concrete, where ducts are cast in and tendons are tensioned after the concrete cures.
3. Advantages of pre-stressed concrete include increased strength, reduced cracking and corrosion, higher span-to-depth ratios, and economic benefits. However, it requires experienced engineers and builders and sections can be brittle.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses determining the deflection of beams under load. It introduces the concepts of bending moment (M), modulus of elasticity (E), and moment of inertia (I) in determining curvature and deflection. The maximum deflection can be obtained by solving the second order differential equation that governs the elastic curve of the beam, using the boundary conditions of the beam's supports and applying any loads. Examples are provided to demonstrate how to set up and solve the differential equations to find the deflection at any point on beams with various load configurations.
This document summarizes research on strengthening reinforced concrete beams using fiber reinforced polymer (FRP) sheets. It discusses how FRP strengthening has become a popular technique worldwide due to advantages like high strength, light weight, corrosion resistance, and easy installation. The document reviews literature on strengthening both simply supported and continuous beams. It outlines different FRP strengthening methods and discusses factors that influence the behavior and failure of strengthened beams, such as surface preparation, adhesive type, and concrete strength. The document also discusses design considerations and challenges for FRP strengthening, as well as disadvantages like lack of design codes and fire risk.
The document discusses mechanics of solid deflection in beams. It provides relationships between bending moment and curvature, as well as sign conventions for shear force, bending moment, slope and deflection. It then analyzes simply supported beams with central point loads and uniform distributed loads. Equations are derived for slope, deflection and bending moment at any section. Cantilevers with point loads and uniform distributed loads are also analyzed. Macaulay's method, a versatile technique for determining slope and deflection in beams under various loading conditions, is introduced. Examples applying the concepts to specific beam problems are included.
Dokumen ini berisi perhitungan struktur slab lantai jembatan di Yogyakarta. Termasuk perhitungan berat sendiri, beban tambahan, beban truk, beban angin, dan pengaruh temperatur untuk mendapatkan momen pada slab. Kemudian dilakukan pemilihan tulangan lentur positif dan negatif berdasarkan momen tersebut dengan mempertimbangkan mutu beton dan baja serta tebal slab.
This document provides an overview of chapter 9 from the textbook "Mechanics of Materials" which covers deflection of beams. It includes sections on the deformation of beams under transverse loading, the equation of the elastic curve, statically indeterminate beams, and methods for determining deflection such as moment-area theorems, superposition, and examples of applying these methods to solve problems. Sample problems are provided throughout to demonstrate solving for beam deflection, slope, reactions and developing the equation of the elastic curve.
This document provides an overview of the slope deflection method for analyzing statically indeterminate structures. It describes that the slope deflection method was developed in 1914 and can be used to analyze beams and frames. Key assumptions of the method are that joints are rigid and distortions from axial/shear stresses are neglected. The document outlines the application, sign convention, procedure, slope deflection equations, and provides examples for analyzing beams and frames using this method.
This document discusses stresses in beams and beam deflection. It covers several methods for analyzing bending stresses and deflection in beams, including: [1] the engineering beam theory relating moment, curvature, and stress; [2] double integration and moment area methods for calculating slope and deflection; and [3] Macaulay's method, which simplifies calculations for beams with eccentric loads. Formulas are provided relating bending moment, shear force, curvature, slope, and deflection. Moment-area theorems are also described for relating bending moment to slope and deflection.
1. The document provides formulas for calculating slope, deflection, and maximum deflection for various beam types under different loading conditions. It gives the equations for cantilever beams with concentrated loads, uniformly distributed loads, and varying loads. It also provides the equations for simply supported beams with these different load types and with couple moments applied. The equations relate the beam properties like length, load location, and intensity to the resulting slope and deflection values.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression before application of service loads. This counters the tensile stresses induced by loads and prevents cracking. There are two main methods: pre-tensioning applies tension before pouring concrete, while post-tensioning tensions strands after concrete curing. Pre-stressed concrete allows for smaller and lighter structures that resist loads, deflection, and cracking better than reinforced concrete.
The document discusses various methods for analyzing beam deflection and deformation under loading, including:
1) Deriving the differential equation for the elastic curve of a beam and applying boundary conditions to determine the curve and maximum deflection.
2) Using the method of superposition to analyze beams subjected to multiple loadings by combining the effects of individual loads.
3) Applying moment-area theorems which relate the bending moment diagram to slope and deflection, allowing deflection calculations for beams with various support conditions.
This document discusses the concept of shear center for beams with non-symmetric cross sections. It defines shear center as the point where a load can be applied such that the beam only bends with no twisting. Formulas to calculate the shear center are presented for common cross sections like channels, I-beams, and circular tubes. Examples of determining the shear center for different cross sections are included. The importance of applying loads through the shear center to prevent twisting is emphasized.
Similar to Relations between Structural Damage and Level of External Prestressing Force on the Flexural Behavior of Post-Tensioned Prestressed Concrete Beams
IRJET - Experimental Investigation of flexural member of Beam Opening in ...IRJET Journal
1) The document experimentally investigates the flexural behavior of reinforced concrete beams with web openings created by inserting PVC pipes.
2) 14 beams were cast and tested under one-point and two-point loading. Beams with PVC pipes in the tension zone below the neutral axis showed higher load capacities compared to solid beams.
3) The results indicate that using PVC pipes in the tension zone is a viable way to reduce concrete usage in beams while maintaining structural performance.
IRJET - Analysis and Model for Flexural Behaviour of Confined Rectangular...IRJET Journal
This document summarizes an analysis of the flexural behavior of confined and unconfined rectangular concrete beams. Three beam samples were tested: one with internal confinement using stirrups, one with external confinement using mesh wrapping, and one without confinement. Testing found that the externally confined beam had the highest load carrying capacity and withstood the greatest strains before failure. The internally confined beam performed better than the unconfined beam but not as well as the externally confined beam. In conclusion, external confinement was found to be the most effective at improving a beam's ductility and strength.
A BEHAVIORAL TESTING STUDY OF ULTRA HIGH PERFORMANCE CONCRETEIRJET Journal
The document presents the results of a study on the behavioral testing of ultra-high performance concrete (UHPC). Several concrete mixes were tested with compressive strengths ranging from M-30 to M-100. Cubes and beams were tested at 7 and 28 days to determine compressive and flexural strengths. The testing found that UHPC exhibited higher strength, durability, and resistance to corrosion compared to conventional and high-strength concretes. Graphs of stress-strain curves showed UHPC has a steeper linear portion and higher modulus of elasticity. UHPC failed in compression through lateral expansion restricted by steel plates, allowing for more ductile failure.
Dynamic Response and Failure Analysis of INTZE Storage Tanks under External B...IRJET Journal
This document analyzes the dynamic response and failure of elevated INTZE storage tanks under external blast loading. It describes modeling INTZE tanks in SAP2000 software and applying blast loads to study displacements, reactions, stresses over time. Frame and shaft footed tanks of varying heights were analyzed both empty and full. Results show shaft footed tanks resist blast loads better due to more mass concrete. Displacements increase with frame tank height but decrease for shaft tanks. Stresses also increase with height for both, but are lower for shaft tanks. Failure analysis indicates pillars and connections initially fail from stress concentrations. The conclusion is shaft footed tanks with maximum height best resist blast loads.
IRJET-Effect of Surface Blast Load on the RC StructuresIRJET Journal
The document discusses the effects of surface blast loads on reinforced concrete structures, outlining methods to calculate blast loads from different amounts of TNT at varying standoff distances and analyzing the storey displacement and drift of models with and without bracing under these loads. The addition of bracing is found to significantly reduce storey displacement and drift to within code allowances, making it an effective but costly method of improving blast resistance in reinforced concrete buildings.
IRJET- Dynamic Properties of Cellular Lightweight ConcreteIRJET Journal
The document discusses the dynamic properties of cellular lightweight concrete (CLC), as studied through various tests. It summarizes the results from split Hopkinson pressure bar (SHPB) tests, cyclic simple shear tests, and impact tests. Key findings include:
1) Dynamic compressive strength and impact toughness of CLC increases with strain rate. Stress-strain curves from SHPB tests show three stages: elastic, plateau, and densification.
2) Cyclic shear tests show stress-strain hysteresis loops decrease in area with increasing shear strain. Backbone curves were obtained by fitting a hyperbolic function to the loops.
3) Maximum shear modulus increases with consolidation pressure but decreases with CLC unit weight.
This document discusses seismic retrofitting of buildings. It begins with an introduction to the need for retrofitting structures due to factors like material deterioration over time or damage from earthquakes. The main steps in retrofitting are assessing damage through non-destructive testing and then strengthening the structure. Two case studies of retrofitting projects are described involving a water tank damaged in an earthquake and a commercial building with cracks. For both, non-destructive tests were conducted to evaluate material strength and appropriate retrofitting measures like jacketing columns and beams or adding bracing were implemented to strengthen the structures. Retrofitting can restore durability and seismic resistance without disrupting existing properties.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- Strength Behaviour of Hardened ConcreteIRJET Journal
The document discusses testing conducted on hardened concrete cylinders drilled from a dam in India to study their stress-strain behavior and determine elastic parameters. 10 concrete cylinder samples were tested for properties like unit weight, water absorption, ultrasonic pulse velocity, modulus of elasticity, Poisson's ratio, and crushing strength. The stress-strain curves of 2 samples tested under controlled strain conditions showed increased strain at failure compared to conventional testing. The results are presented in a table and figures showing typical stress-strain behaviors.
Study of behaviour of composite beams with truss type shear connectoreSAT Journals
This document summarizes a study that used finite element analysis to optimize the design of truss-type shear connectors used in composite beams. Various parameters of the shear connectors were analyzed, including angle of inclination, bar diameter, and depth of embedment. Angles between 60-75 degrees were found to be most efficient, with minimal changes when bar diameters were varied. The ultimate load capacity was found to be independent of depth of embedment. Additional models analyzed the influence of cohesion and friction at the interface, finding that cohesion up to 2 MPa resulted in behavior similar to a solid beam.
IRJET- Study of Cold-Formed Steel Flexural Member Under Monotonic and Reverse...IRJET Journal
1) The document describes a study on the behavior of cold-formed steel build-up beams under monotonic and reversed cyclic loading. Beams made of open and closed steel sections were connected using various fastening methods and tested under different end conditions.
2) Tests were conducted to evaluate the strength, failure modes, hysteresis behavior, and effects of parameters like lipped sections. Beams with lipped sections showed higher strength and stiffness compared to plain beams.
3) Finite element analysis was also used to validate the experimental results. The strengths obtained from experiments agreed reasonably well with the finite element analysis.
This study analyzed the behavior of reinforced concrete columns retrofitted with textile reinforced concrete (TRC) under blast loading using finite element modeling.
The study modeled RC columns and TRC retrofitted columns, applied blast loads from TNT explosions at different standoff distances, and compared the dynamic response. Materials properties and modeling techniques were described.
Results showed that TRC strengthening reduced column deflections compared to unretrofitted columns, and maximum deflection decreased exponentially with increased standoff distance. Circular retrofitted columns performed better than square. TRC retrofitting is an effective solution to limit blast damage.
Structural Analysis of Blast Resistant BuildingsIRJET Journal
1) The document analyzes the structural response of a 20-story building model with shear walls and one with steel braces when subjected to blast loads from explosives at varying distances.
2) Finite element analysis was used to simulate blast loads from explosives weighing 150kg and 250kg placed 25m and 50m from the structures. Storey displacements and drifts were compared.
3) Results showed the structure with steel braces experienced greater displacements and drifts than the structure with shear walls in most scenarios, indicating the shear wall structure was more blast resistant.
IRJET-Design and Strength Analysis of a Tilting Mechanism for Steel StructuresIRJET Journal
1) The document describes the design of a tilting mechanism for steel beams that exit an extrusion process. The mechanism is needed to remove pickle liquor, which contains acids, from the beams' surfaces.
2) The designed mechanism uses 4 individual mechanisms connected to a conveyor belt to support the heavy weight of 12-13 steel beams at a time. Strength analysis using FEM modeling showed the mechanism can safely support up to 2.35 tons of weight.
3) The mechanism works by lifting and tilting the beams 90 degrees to drain off the maximum amount of pickle liquor. The document concludes the designed tilting mechanism is able to perform its intended function of removing liquid from the steel beams.
1. The study investigated the failure mechanisms of interfaces between existing and new widened reinforced concrete deck slabs with external prestressing.
2. Tests on interface specimens found that increasing prestressing level increased shear capacity by reducing joint opening and increasing effective interface area. Higher reinforcement ratio decreased shear capacity but increased stiffness.
3. Surface roughness significantly affected behavior - rough interfaces developed diagonal cracks while smooth interfaces failed in shear. Bending moment at the interface also influenced cracking and capacity.
The document summarizes an experimental study that investigated the friction coefficient between concrete block and steel plate bolted joints. Specifically, it tested 30 specimen groups to determine the effects of various parameters on the friction coefficient, including: the type and amount of glue between the concrete and steel surfaces; the type, size, and amount of sand on the concrete surface; the shape and dimensions of grooves in the steel plate; and the bolt pre-tightening force. The experiments found that the friction coefficient increased with greater amounts of glue on the steel plate surface and higher bolt pre-tightening pressures. It also examined using different sizes of sand and shapes of steel plate grooves to optimize the friction coefficient.
This document contains a lesson plan and materials for an engineering materials course. The lesson plan outlines 12 topics to be covered across 12 weeks, including introduction to materials and atomic bonding, mechanical properties testing, tribology, fatigue analysis, corrosion, metals and alloys, polymers and ceramics, materials selection, and revision. Key concepts and learning objectives are defined for each topic. The document also provides examples and explanations to supplement the lesson content, such as definitions of toughness, descriptions of impact testing methods, diagrams of stress-strain curves for ceramics, and examples of calculating flexural strength and modulus from three-point bending tests. References for the course materials are also listed.
Upgradation of non ductile reinforced concrete beamcolumn connections using f...IAEME Publication
This document summarizes an experimental study on upgrading non-ductile reinforced concrete beam-column connections using polyester fiber. Specimens of beam-column connections with varying amounts of polyester fiber (0%, 1%, 1.5%, 2% by volume) were subjected to cyclic loading. Test results showed that the addition of polyester fiber increased the ultimate strength, energy dissipation, and stiffness of the connections compared to the non-ductile control specimen. The polyester fiber improved the ductility of the connections and led to more uniform cracking and higher deformability. Increasing the polyester fiber content resulted in higher strength, stiffness degradation resistance, and energy absorption of the beam-column connections.
Simulation of Critical Crack Length Propagation Using Fracture Mechanicsijceronline
The document discusses simulation of critical crack length propagation using fracture mechanics principles. It provides background on different types of material failures including buckling, ductile fracture, and brittle fracture. It then discusses fatigue failures and calculates critical crack length, strain amplitude, and mean stress for steel, aluminum, and epoxy materials using linear elastic fracture mechanics. The results show aluminum has the highest strength and life cycle while epoxy has the lowest. It concludes that mixing aluminum and epoxy could increase the life cycle of epoxy materials.
This document compares the performance of a proposed innovative lightweight concrete filled steel tubular (CFST) truss bridge to a conventional reinforced cement concrete bridge through finite element analysis using ANSYS software. Two bridge models are created - a conventional RCC bridge and a CFST bridge. Both bridges are 15m in span and subjected to various loads. The analysis finds that the maximum deformation, normal stress, and normal strain for both bridges are within acceptable limits, with the CFST bridge performing better with lower deformation. It is concluded that the CFST bridge design suggests an alternative construction method for bridges.
Similar to Relations between Structural Damage and Level of External Prestressing Force on the Flexural Behavior of Post-Tensioned Prestressed Concrete Beams (20)
11(7) 2020 ITJEMAST's published research articlesdrboon
This document summarizes a research study that examined the relationship between positivity, positive affect, negative affect, and perceived stress among cardiac patients. The study hypothesized that perceived stress would mediate the relationship between positivity and positive/negative affect. Researchers surveyed 519 cardiac patients, assessing positivity, perceived stress, and positive/negative affect. The results found that perceived stress mediated the relationship between positive affect and positivity, as well as between negative affect and positivity. Specifically, positivity was negatively correlated with negative affect and perceived stress, while perceived stress was positively correlated with negative affect. The findings suggest that reducing stress and increasing positive emotions can help reduce negative feelings in cardiac patients.
11(4) 2020 ITJEMAST Multidisciplinary Research Articlesdrboon
Research papers 2020 Behavioral finance; Personality traits; Behavioral factors; Overconfidence bias; Locus of control; Decision-making; Biased behavior Carbon (CO2) emissions; Economic Growth; Energy consumption; Trade; ARDL Approach; Granger Causality; Energy use Pedestrian start-up time; Street crosswalk, Pedestrian traffic signals; Pedestrians traffic lights; zebra crossings; Intersection crossings Service Attributes; Relationship quality; Relationship outcomes; Banking services; Electronic Customer Relationship Management; Virtual relationships; eBanking; eCRM College town landscape; College town character; Campus community; Urban identity; College town space; Sense of a place; Public Space; University gardens; Cultural identity; Campus identity; Businesses in college towns Emotional quotient; Self-emotional appraisal; Workplace Advice Network (WAN) Centrality; Service Sector Organizations; Sociometric matrix; Interconnectivity of nodes
11(3) 2020 ITJEMAST Multidisciplinary Research Articles drboon
Non-destructive testing method Heat loss Thermal conductivity Specific heat Know-how Psychological contract breach Employees' Workplace behaviour Workplace spirituality Human resource management (HRM) Power sector Positive classroom Male teachers Classroom management system Public primary schools Private primary school Positive motivation students Quality primary education Grout rheology Construction workings High-precision lining Tunneling complex Cement slurry Reinforcement solutions Smart building systems Green architecture Green roof Green design Sustainable environmental architecture Smart energy management Architecture technology Neo-Functionalism Trade integration CPEC agreement Economic integration Regional cooperation Pak-China relations Pak-Iran relations Central Asia Republics Sino-Pakistan Agreement
11(2)2020 International Transaction Journal of Engineering, Management, & Ap...drboon
Multidisciplinary Management, Journalism and Mass Communication Science (Information and Media Sciences), Political Sciences (International Affairs), Global Studies), Animal Sciences, Feeding Technology, Healthcare Management.
V8(3) 2017:: International Transaction Journal of Engineering, Management, & ...drboon
Research articles published in V8(3) 2017:: International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies ==>
Awareness of Passive Design on Apartment Façade Designs in Putrajaya, Malaysia
127
Comparative Analysis of Low-Cost Housing Policies in Malaysia and Nigeria
139
A Study on Kevin Lynch’s Urban Design Elements: Precinct 9 East Putrajaya
153
Investigating Urban Design Elements of Bandar Baru Sentul, Kuala Lumpur
169
A Study on Sharing Home Ownership Schemes in Malaysia
183
The Impact of Window to Wall Ratio (WWR) and Glazing Type on Energy Consumption in Air-Conditioned Office Buildings
197
Competitiveness Factors of Thai Construction Industry within the AEC Context: A Qualitative Approach
209
Application of Confirmatory Factor Analysis in Government Construction Procurement Problems in Thailand
221
In 3 sentences:
The document discusses the key elements to consider when designing streets for livable cities, including pedestrians, vehicles, parking, and transportation options. It emphasizes the need for a comprehensive approach that considers all users and aspects, such as transportation, safety, the environment, and the economy. The goal is to create streets that are social spaces where people can easily and safely walk, bike, access transit, and spend time, rather than only focus on traffic flow.
Impact of Building Envelope Modification on Energy Performance of High-Rise A...drboon
This document summarizes a research study that investigated the impact of building envelope modifications on the energy performance of high-rise apartments in Kuala Lumpur, Malaysia. Three high-rise apartment buildings were modeled using EnergyPlus software to analyze the effects of thermal insulation and glazing type on potential energy savings. The study found that integrating passive envelope design measures like improved insulation and higher performing glazing could help reduce energy consumption and peak cooling loads in the apartments. Modifying elements of the building envelope, especially the walls and windows, may enable significant energy savings potential for high-rise residential buildings in hot and humid climates.
Enhancement of Space Environment Via Healing Gardendrboon
Green nature, sunlight and fresh air have been known as important component of healing in healthcare facilities. This paper presents the finding of an exploratory study on healing garden elements in healthcare facilities. The purpose of the paper is to find the elements of healing gardens and its healing factors in the existing garden design. In conducting this research study, site observation and informal interview at selected healthcare facilities have been performed. The study reveals the elements of existing garden design, the interactivity and the end users expectation on a garden. The finding shows that lacking some of the elements of garden design lead to less user friendliness and interactivity in the garden. It also shows that the visibility, accessibility, quietness and comfortable condition in the garden give impact to the utilization of the garden.
Design of Quadruped Walking Robot with Spherical Shelldrboon
We propose a new quadruped walking robot with a spherical shell, called "QRoSS." QRoSS is a transformable robot that can store its legs in the spherical shell. The shell not only absorbs external forces from all directions, but also improves mobile performance because of its round shape. In rescue operations at a disaster site, carrying robots into a site is dangerous for operators because doing so may result in a second accident. If QRoSS is used, instead of carrying robots in, they are thrown in, making the operation safe and easy. This paper reports details of the design concept and development of the prototype model. Basic experiments were conducted to verify performance, which includes landing, rising and walking through a series of movements.
Motion Analysis of Pitch Rotation Mechanism for Posture Control of Butterfly-...drboon
We developed a small flapping robot on the basis of movements made by a butterfly with a low flapping frequency of approximately 10 Hz, a few degrees of freedom of the wings, and a large flapping angle. In this study, we clarify the pitch rotation mechanism that is used to control its posture during takeoff for different initial pitch and flapping angles by the experiments of both manufactured robots and simulation models. The results indicate that the pitch angle can be controlled by altering the initial pitch angle at takeoff and the flapping angles. Furthermore, it is suggested that the initial pitch angle generates a proportional increase in the pitch angle during takeoff, and that certain flapping angles are conducive to increasing the tendency for pitch angle transition. Thus, it is shown that the direction of the flight led by periodic changing in the pitch angle can be controlled by optimizing control parameters such as initial pitch and flapping angles.
Analysis of Roll Rotation Mechanism of a Butterfly for Development of a Small...drboon
1) The document analyzes the roll rotation mechanism of a butterfly through computational fluid dynamics simulations using boundary conditions from high-speed camera footage.
2) It finds that during typical pitch rotation flight, differential pressure concentrates at the tip of the forewings, producing roughly matched reaction forces on the left and right wings.
3) During roll rotation flight, differential pressure distributes across the entire wings, with the right reaction force twice as great as the left during the initial downstroke, leading to a large change in roll angle.
Effect of Oryzalin on Growth of Anthurium andraeanum In Vitrodrboon
Apical shoots and lateral buds of Anthurium andraeanum about 0.5 cm grew very well when cultured on MS medium supplemented with NAA, kinetin, sucrose and gelrite. When brought young plantlets (the same sized) of A. andraeanum soaked in various concentrations of oryzalin with different duration times. The A. andraeanum plantlets were subcultured into the same medium every 4 weeks for 3 times. It was found that 5.0 mg/l oryzalin with 24 and 72 hours gave the best average number of leaves per bunch, plant height and diameter of bunch. These parameters were reverse proportion, when increased concentration of oryzalin, the growth rate in each parameter was decreased with thick and pale green leaves.
Role of 2,4-D on Callus Induction and Shoot Formation to Increase Number of S...drboon
Stem node of Miniature Rose with axillary bud were used as explants. These explants cultured on MS medium supplemented with different concentrations of 2,4-D. It was found that MS medium supplemented with 0.5 mg/l 2,4-D gave the highest number of green callus. The callus cultured on MS medium supplemented with different combinations of NAA and BA to form new shoot and root. From the result, we are able to find the highest number of young shoots that were induced from callus when cultured callus on MS medium supplemented with NAA and BA. When subcultured all new shoots with the same size to MS medium supplemented with different concentrations of NAA and BA, and 2,4- D for six weeks. The result was significant difference (P≤0.5) when compared the average height of plant and percentage of root formation, but their duration time for flowering were not significant different.
Seismic Capacity Comparisons of Reinforced Concrete Buildings Between Standar...drboon
Earthquakes are cause of serious damage through the building. Therefore, moment resistant frame buildings are widely used as lateral resisting system. Generally three types of moment resisting frames are designed namely Special ductile frames (SDF), Intermediate ductile frames (IDF) and Gravity load designed (GLD) frames, each of which has a certain level of ductility. Comparative studies on the seismic performance of three different ductility of building are performed in this study. The analytical models are considered about failure mode of column (i.e. shear failure, flexural to shear failure and flexural failure); beam-column joint connection, infill wall and flexural foundation. Concepts of incremental dynamic analysis are practiced to assess the required data for performance based evaluations. This study found that the lateral load capacity of GLD, IDF, and SDF building was 19.25, 27.87, and 25.92 %W respectively. The average response spectrum at the collapse state for GLD, IDF, and SDF are 0.75 g, 1.19 g, and 1.33 g, respectively. The results show that SDF is more ductile than IDF and the initial strength of SDF is close to IDF. The results indicate that all of frames are able to resistant a design earthquake.
ITJEMAST5(2): Latest Research from International Transaction Journal of Engin...drboon
An After-Stay Satisfaction Survey of Residents Living in Prefabricated Concrete Structures in Thailand
Hydrothermal Assisted Microwave Pyrolysis of Water Hyacinth for Electrochemical Capacitors Electrodes
Group Technology Paves the Road for Automation
Effect of Laser Priming on accumulation of Free Proline in Spring Durum Wheat (Triticum turgidum L.) under Salinity Stress
Livable Public Open Space for Citizen’s Quality of Life in Medan, Indonesia
ITJEMAST5(1): Latest Research from International Transaction Journal of Engin...drboon
Latest Research from International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies ITJEMAST5(1):
Effects of Calcination Treatment of Diatomite on Dimethyl Ether Synthesis from Methanol
Effect of Blend Ratio on Cure Characteristics, Mechanical Properties, and Aging Resistance of Silica-filled ENR/SBR Blends
An Efficient Formulation of Off-line Model Predictive Control for Nonlinear Systems Using Polyhedral Invariant Sets
Effect of Modeling Parameters on System Hydrodynamics of Air Reactor in Chemical Looping Combustion Using CFD Simulation
Flow Behavior of Geldart A and Geldart C Particles in a Co-current Downflow Circulating Fluidized Bed Reactor
Optimization of Enzymatic Clarification from Corncob
Synthesis of Alkali Metal/CaO Sorbent for CO2 Capture at Low Temperature
Effect of Exchangeable Cations on Bentonite Swelling Characteristics of Geosy...drboon
1) The study characterized the swelling behavior of bentonite in geosynthetic clay liners (GCLs) using X-ray diffraction and scanning electron microscopy.
2) The X-ray diffraction results showed that bentonite swelling decreased with increasing valence of exchangeable cations and increasing concentration of permeant solutions. Bentonite swelling was highest with deionized water and lowest with calcium chloride solutions.
3) Scanning electron microscopy images showed that bentonite has a flake-like structure when air-dried but becomes more porous and fluffy after permeation. The porous structure decreased with increasing concentration of calcium chloride solutions.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
Boost your website's visibility with proven SEO techniques! Our latest blog dives into essential strategies to enhance your online presence, increase traffic, and rank higher on search engines. From keyword optimization to quality content creation, learn how to make your site stand out in the crowded digital landscape. Discover actionable tips and expert insights to elevate your SEO game.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
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Relations between Structural Damage and Level of External Prestressing Force on the Flexural Behavior of Post-Tensioned Prestressed Concrete Beams
1. 2013 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies.
International Transaction Journal of Engineering,
Management, & Applied Sciences & Technologies
http://TuEngr.com
Relations between Structural Damage and Level of
External Prestressing Force on the Flexural Behavior
of Post-Tensioned Prestressed Concrete Beams
a
Thananun Phuwadolpaisarn , Sayan Sirimontree
a
a*
, and Boonsap Witchayangkoon
a
Department of Civil Engineering Faculty of Engineering, Thammasat University, THAILAND
ARTICLEINFO
ABSTRACT
Article history:
Received 20 May 2013
Received in revised form
09 July 2013
Accepted 10 July 2013
Available online
10 July 2013
Prestressed concrete beams can be damaged by overloading
beyond cracking stage leading to the reduction of flexural rigidity and
excessive deflection. The progressive of damage, crack and permanent
deflection can be occurred at the high level of load after cracking.
Structural performance of damaged girder can be recovered and
improved by external post tension. The level of external prestressing
force required in strengthening depends directly on the level of
damage due to overloading. This research studied the effect of levels
of damage on flexural rigidity, crack and deflection of the test girder.
Three levels of damage can be expressed in terms of 0.65, 0.75 and
0.85 times the predicted ultimate load of the test beam. Three levels of
external prestressing forces (2, 2.5 and 3 times of the internal
prestressing force applied in undamaged reference beam) are applied
in strengthening at each level of damage. The results show that
reduced flexural rigidity, increased permanent deformation and crack
width due to overloading can be recovered by external post tension.
Strengthening by means of external post tension can be effectively
applied to the damaged beam at the level of damage not more than
0.65 times of predicted ultimate load.
Keywords:
Flexural rigidity
Post-Tension;
Strengthening;
Repair Prestress;
Structural rigidity;
Beam girder;
Full scale test.
2013 INT TRANS J ENG MANAG SCI TECH.
1. Introduction
Concrete beam has been widely used in the long span bridge structure as prestressed
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
241
2. concrete (PC) is designed uncrack section under applied load. This makes deflection and
cross-sectional area less than reinforced concrete (RC) beams. However, when the applied
load exceeds uncrack load, PC beam behavior becomes similar to RC beam with increased
deflection. In addition, enlarged crack-widths cause reinforced steels to grow rusty. As a
result, flexural rigidity is reduced. Such increasing crack and higher deflection make the beam
unsuitable for use anymore. Strengthening the deteriorated beam by external prestressing can
help reduce the crack and deflection. Flexural rigidity should be increased such that it makes
the beam to serve its regular job. In addition, beam flexural moment capacity is higher at the
ultimate state. The level of external prestressing force is correlated with the damaged level of
the flexural rigidity of concrete post-tension system.
Figure 1: Casting and Details of tested PC-beam specimen.
242
Thananun Phuwadolpaisarn, Sayan Sirimontree, and Boonsap Witchayangkoon
3. This research studied the effect of external prestressing force on the flexural behavior
of damaged prestressed concrete beams under cyclic static loading. This work focuses flexural
behavior in terms of flexural rigidity, cracks, deflection, and flexural moment capacity. We
test the beam with overloading 0.65, 0.75 and 0.85 times the predicted ultimate load. At each
overloading level, varied strengthening with external prestress is executed.
2. Method
2.1 Test Bean Design
PC T-beam has been built having length 6m, depth 0.55m, flange width 0.8m, and
thickness 0.1m.
Concrete strength (
prestressing strands grade 270 (
) is 35Mpa.
This beam is installed with two
1860Mpa), each with diameter 12.7mm. The strands are
placed with parabola shape as shown in Figure 1.
The beam has been predesigned to have enough shear reinforcement steel to prevent shear
failure. PC strands were stressed to 0.75
at transfer stage. Cement grouting is filled into
the steel duct to bond the strands to surrounding concrete.
2.2 Loading Setup
Static loading and unloading is performed in testing process. Load is applied using
hydraulic hand pump. Two-point loading is set up through the use of transfer beam. Distance
between two-point loading is 2.5m. This setup makes zero shear between two-point loading,
thus moment effect can be fully observed.
2.3 Instrumental Setup
Applied load can be measured by load cell. Dial gauges and displacement transducers are
installed throughout beneath the beam to measure deflection. Strain gauges are installed at top
and bottom longitudinal steels and both side concrete surface of tested beam. Measured data
are monitored by data logger and recorded in the computer system. Cracks are visually
observed and marked.
2.4 Testing and strengthening Process
Loading is increased 1 ton at a time until the first crack (
theoretically 8.5 tons) is
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
243
4. visually observed, then load is increased at 0.5 ton at a time until the load reaches 1.2 time of
actual
. Then, the load is fully unloaded and then loaded to 1.2
. The unloaded and then
loaded process is repeated for ten cycles. This cyclic process is for observation of flexural
rigidity loss, cracking and permanent cumulative deflection. Figure 2 shows levels phase of
the test beam applied load is inflate.
Load P ( TON )
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Pu
0.85 Pu
0.75 Pu
0.65 Pu
1.2 Pcr
Pcr
Pcr = 8.5 TON
1.2 Pcr = 10.2 TON
0.65 Pu = 11.7 TON
0.75 Pu = 13.5 TON
0.85 Pu = 15.3 TON
P ultimate = 18 TON
Mid Span Deflection ( mm.)
Figure 2: Level phase of loading and external prestressing.
The applied load is further increased to 0.65 time of predicted ultimate loading capacity of
the test beam (
= 18
). The cyclic process of fully unloaded and loaded to 0.65
(11.7
ton) is repeated for ten cycles. The deflection after the tenth cyclic is used for deflection
control in the subsequence test of the degraded beam strengthening by external post tension (see
Figure 3). The 1st level of external prestressing force, 28 tons (2 , = internal prestressing
force of original undamaged beam), was used to strengthen the degraded beam and then testing
to the specified deflection and unload. External strands were removed and then the new external
strands were applied to the damaged beam with the external prestressing force equal to 2.5
or
40 tons. The specimen was tested to the maximum specified deflection. After unloading,
external strands were removed and new strands with external prestressing forces equal to 3
or 52 tons were applied to damaged beam and test to specified deflection.
244
Thananun Phuwadolpaisarn, Sayan Sirimontree, and Boonsap Witchayangkoon
5. Figure 3: Testing beam with external post-tension.
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0.85 Pu
0.75 Pu
0.65 Pu
Load P ( TON)
1.2 Pcr
Pcr
0
2
4
6
8
10 12 14 16 18 20 22 24 26 28 30 32
Mid Span Displacement (mm.)
Figure 4: Relationship of load and mid span deflection of all cyclic load.
Figure 5: Crack width damage and external post-tension
External strands were removed and the test specimen was tested cyclically to 0.75 .
Maximum deflection in this test was used as specified deflection in subsequence test. Three
levels of external prestressing forces were applied to the degraded beam and test in the same
manners as for the beam with damaged level of 0.65 .
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
245
6. Load P (TON)
Load P (TON)
Load P (TON)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Mid Span Deflection (mm.)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Mid Span Deflection (mm.)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Mid Span Deflection (mm.)
1.2 Pcr Round 1
0.65 Pu Round 10
External 28 TON
External 40 TON
External 52 TON
1.2 Pcr Round 1
0.75 Pu Round 10
External 28 TON
External 40 TON
External 52 TON
1.2 Pcr Round 1
0.85 Round 10
External 28 TON
External 40 TON
External 52 TON
Figure 6: Relationship of load and mid span deflection each level of damage strengthened by
external post tension.
246
Thananun Phuwadolpaisarn, Sayan Sirimontree, and Boonsap Witchayangkoon
7. Load P (TON)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
1.2 Pc Round 1
External 28 TON
External 40 TON
External 52 TON
Load P (TON)
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Mid span displacement (mm.)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
1.2 Pc Round 1
External 28 TON
External 40 TON
Load P (TON)
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Mid span displacement (mm.)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
External 52 TON
1.2 Pc Round 1
External 28 TON
External 40 TON
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Mid span displacement (mm.)
External 52 TON
Figure 7: Relationship of load and mid span deflection each level of damage strengthened by
external post tension shift graph
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
247
8. Load P (TON)
10
9
8
7
6
5
4
3
2
1
0
L: 800
Pcr
0.85 Pcr
1.2 Pc Round 1
0.65 Pu Round 10
0.75 Pu Round 10
0.85 Pu Round 10
0
1
2
3
4
5
6
7
8
9 10
Load P (TON)
Mid span displacement (mm.)
10
9
8
7
6
5
4
3
2
1
0
1.2 Pc Round 1
0.65 Pu Ext 28 T
0.65 Pu Extl 40 T
0.65 Pu Ext 52 T
0.75 Pu Ext 28 T
0.75 Pu Ext 40 T
0.75 Pu Ext 52 T
0.85 Pu Ext 28 T
0.85 Pu Ext 40 T
0.85 Pu Ext 52 T
0
1
2
3
4
5
6
7
8
9 10
Mid span displacement (mm.)
Figure 8: Working load and allowable deflection.
The same testing procedures and external post tension were applied to the damaged beam
which was loaded to 0.85 .
248
Thananun Phuwadolpaisarn, Sayan Sirimontree, and Boonsap Witchayangkoon
9. 3. Results
Figure 4 shows the relationship between the load and deflection pattern, repeated for 10
cycles at load 1.2 Pcr, 0.65 Pu, 0.75 Pu and 0.85 Pu. When reaching crack load Pcr (8.5 tons
add), cracks can be observed, as in Figure 5. Main crack is larger causing loss of section
properties and thus flexural rigidity is reduced. This is indicated by the slope of the linear
relationship between load and deflection (Figure 4). Moreover, the permanent deflection is
increased according to damaged level. It can be noticed that the beam has a lower elasticity
depending on the level of damage. After crack with loading between 1.2 Pcr - 0.65 Pu, the test
gives that proportional limit is reduced from 8.5 tons to 4 tons.
With increased damage from
additional load, permanent cumulative deflection becomes higher while proportional limit is
lower.
Figure 6 shows beam strengthening with external post tension at various damaged level.
At all levels of applied load, when using external prestressing force 28tons, the beam cannot
rehabilitate into its original state.
However, when using external prestressing force 40 and
52tons, the beam has cambered compared to its original state.
This external post tension
helps crack reduction, improves section properties to become almost uncrack section (smaller
crack width), enhances elasticity of the beam, and develops higher flextural rigidity.
In
addition, ultimate load is likely to increase with increased external prestressing force.
4. Discussion
From the test when overloading is applied, crack seems to cumulate.
Likewise,
permanent deflection seems to increase according to increased damage. These result in
flexural rigidity to decrease.
When the damaged beam is rehabilitated via external
post-tension, crack width and permanent deflection appear to decrease and flexural rigidity to
increase. Figure 7 shows slope of load and deflection. When damage is little, external
post-tension improves flexural rigidity to level almost similar to undamaged beam. On the
other hand, when beam damage is huge, effect of external post-tension per flexural rigidity will
decrease. However if the deflection at service stage is within standard specification, external
post-tension should be acceptable. For all cases, rehabilitated beam by external post-tension
can bear higher ultimate load.
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
249
10. Considering deflection at working load, this study uses working load at 85% of cracking
load (0.85
) of undamaged beam. When damage increases, working load deflection will
increase accordingly due to loss flexural rigidity as a result of crack. Normal maximum bridge
deflection is
, where L is bridge beam span. It can readily be seen that damaged beam
and 0.85
under load 0.75
the deflections is higher than maximum allowable deflection,
see Figure 8. For all cases, when the crack beam is rehabilitated, working load deflection is
reduced to be less than allowable deflection. Taking advantage of prestressing, deflection due
to excessive loading over standard specification can be reduced by means of external
post-tension.
5. Conclusion
Prestressed concrete beams subjected to overloading beyond cracking stage leads to
crack, reduction of flexural rigidity and excessive deflection. The damage, crack and
permanent deflection can be progressed at the high level of load after cracking stage.
Structural performance of damaged girder can be recovered and improved by external post
tension. This work studied about the effects of damage level on flexural behaviors of PC
beam and level of external prestressing forces on flexural behaviors of damaged girder
atrengthened by external post tension. The following conclusions can be made.
Flexural rigidity of the test girder reduced with the increase level of damage due to the
accumulation of crack caused by overloading.
Proportional limit reduce while permanent
deformation increase due to the deposition of damage. Deflection of the test girder at service
stage exceed the acceptable limit at high level of damage.
External post tension with various external prestressing force can be applied to the
damaged girder to recover flexural stiffness and ultimate moment capacity of the test beam.
Elasticity in terms of proportional limit can be improve due to the reduction of crack width
leading to the deflection of the beam fall into the acceptable limit at working stage.
Strengthening of damaged beam can be effectively applied to the test beam for the damage
level not greater than 0.65 times of predicted ultimate load.
250
Thananun Phuwadolpaisarn, Sayan Sirimontree, and Boonsap Witchayangkoon
11. 6. References
Naaman , A.E. and A. Siriaksorn , 1979 . Serviceability ased Design of Partially Prestressed
Beams: Part: Analytical Formulation . Journal of the Prestressed Concrete Institute,
24(2): 64-89.
Limsuwan, E.,and Sirimontree S., 2003 . Rehabilitation of Highway Girders by External
Posttensioning with High Performance Concrete Overlay. FIB Symposium Athens, Greece.
Sirimontree,S., and Limsuwan E. 2002 , Srengthening of
Degraded Concrete Bridge
Girder by Means of External Post Tensioning , The 8th National Convention on Civil
Engineeringc, Khonkean, Thailand.
Edward G. Nawy, 1996 . Fundamentals of High Strength and High Performance Concrete ,
Longman , p142.
R. Park and T. Paulay, 1975. Reinforced Concrete Structures, John Wiley & Sons, New York.
Sayan Sirimontree and Jaruek Teerawong , 2009 .Simplified Analytical Model for Prediction
of Flexural Behaviors of PC Girders , IABSE(International Association of Bridge and
Structural Engineering) Symposium , Bangkok.
Branson, D. E., 1977. Deformation of Concrete Structures,
McGraw-Hill, New York,
Kanisorn, Piyatrapoomi, 2011. Effects of Structural Damage and External prestressing on
Flexural Rigidity and Natural Frequencies of Post-Tensioned Prestressed concrete
Beams. , Master’s thesis, Thammasat University, Faculty Civil Engineering, Thailand.
Thananun Phuwadolpaisarn earned his bachelor degree in Civil Engineering from Thammasat
UniversityThailand, in 2009. He has been studying for the M. Eng. Degree in the Department of Civil
Engineering, Thammasat University. He is currently working at the E.K.D. Engineering and Supply
Dr. Sayan Sirimontree earned his bachelor degree from Khonkaen University Thailand, master degree in
Structural Engineering from Chulalongkorn University Thailand and PhD in Structural Engineering from
Khonkaen University Thailand. He is an Associate Professor at Thammasat University Thailand. He is
interested in durability of concrete, repair and strengthening of reinforced and prestressed concrete structures.
Dr. B. Witchayangkoon is an Associate Professor of Department of Civil Engineering at Thammasat
University. He received his B.Eng. from King Mongkut’s University of Technology Thonburi with Honors.
He continued his PhD study at University of Maine, USA, where he obtained his PhD in Spatial Information
Science & Engineering. Dr. Witchayangkoon current interests involve applications of emerging technologies
to engineering.
Peer Review: This article has been internationally peer-reviewed and accepted for publication
according to the guidelines given at the journal’s website.
*Corresponding author (S.Sirimontree). Tel/Fax: +66-2-5643008 Ext 3112 E-mail address:
2013. International Transaction Journal of Engineering, Management,
ssayan@engr.tu.ac.th
& Applied Sciences & Technologies. Volume 4 No.4
ISSN 2228-9860 eISSN 1906-9642.
Online Available at http://TuEngr.com/V04/241-251.pdf
251