Pre-stressed concrete is a method for overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete. Pre-stressing tendons (generally of high tensile steel cable or rods) are used to provide a clamping load which produces a compressive stress that balances the tensile stress that the concrete compression member would otherwise experience due to a bending load. The pre-stressing force offsets the tensile stress and eliminates the tensile strain allowing the beam to resist further higher loading or to span longer distance.
Prestressed concrete is concrete that is placed under compression prior to service loads being applied through tensioning of steel tendons. This counteracts tensile stresses from loads to improve the performance of the concrete. Eugene Freyssinet is considered the father of prestressed concrete, developing techniques like high strength steel wires and conical wedges for post-tensioning in the 1930s-1940s. Prestressing can be through pre-tensioning or post-tensioning, depending on if the steel is tensioned before or after the concrete is cast. Popular post-tensioning systems include Freyssinet, Magnel Blaton, Gifford-Udall, and Lee-McCall methods. Prestressed concrete provides
Prestressed concrete structures and its applications By Mukesh Singh GhuraiyaMukesh Singh Ghuraiya
1. What is Prestressed??
2. Principle of Prestressed
3. Method of prestressing
4. Prestressed concrete structures
5. Advantages/application of Prestressed concrete
6. Disadvantages of Prestressed concrete
7. Comparison of RCC and Prestressed Concrete Flat Slabs
A system of prestressing involves tensioning tendons and securing them firmly to concrete. There are two main types: pre-tensioning and post-tensioning. Pre-tensioning involves pulling tendons tight between anchored abutments before concrete is poured. The Hoyer or long-line pre-tensioning system uses bulkheads to stretch wires over which molds are placed for concrete pouring. The Freyssinet system was the first post-tensioning method, using a cable of high-strength wires grouted into a duct within the concrete beam. Wires are anchored using conical plugs pushed into holes in concrete cylinders after jacking. The Magnel Blaton system tensions wires in pairs using sandwich plates
Prestressed concrete is concrete that is placed under compression using tensioned steel strands, cables, or bars. This is done through either pre-tensioning or post-tensioning. In pre-tensioning, the steel components are tensioned before the concrete is poured, while in post-tensioning, the steel components are tensioned after the concrete has hardened. Prestressed concrete provides benefits over reinforced concrete like lower construction costs, thinner structural elements, and longer spans between supports.
Pre stressed concrete- modular construction technologyAnjith Augustine
This document provides an overview of pre-stressed concrete, including its history, types (pre-tensioning and post-tensioning), materials, applications, advantages, and tensioning devices. Some key points include: pre-stressed concrete was developed in the 1930s-1940s and the first pre-stressed concrete bridge was built in India in 1948; it uses high-strength steel tendons to put concrete under compression and improve its tensile strength; common applications include bridges, buildings, and other structures; and advantages are increased strength, reduced cracking, and lighter/thinner designs.
This document discusses column jacketing, which is a method of retrofitting and strengthening existing columns. It involves adding reinforced concrete, steel, or fiber-reinforced polymer around the column. The key steps are preparing the column surface, adding shear keys and reinforcement, applying a bonding agent, and casting the new concrete or installing the jacket. Column jacketing increases the strength and seismic capacity of the column. It improves confinement and increases axial, shear, and foundation load capacity without significant weight addition.
Prestressed concrete combines high-strength concrete and high-strength steel in an active manner by tensioning steel tendons and holding them against the concrete, putting it into compression. This transforms concrete from a brittle to a more elastic material. It allows for optimal use of each material's properties and better behavior under loads. Prestressed concrete was pioneered in the 1930s and its use has expanded, finding applications in bridges and other structures. Common methods are pretensioning and post-tensioning, using various tendon types, with bonded or unbonded configurations. Tensioning is done using mechanical, hydraulic, electrical or chemical devices.
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.
Prestressed concrete is concrete that is placed under compression prior to service loads being applied through tensioning of steel tendons. This counteracts tensile stresses from loads to improve the performance of the concrete. Eugene Freyssinet is considered the father of prestressed concrete, developing techniques like high strength steel wires and conical wedges for post-tensioning in the 1930s-1940s. Prestressing can be through pre-tensioning or post-tensioning, depending on if the steel is tensioned before or after the concrete is cast. Popular post-tensioning systems include Freyssinet, Magnel Blaton, Gifford-Udall, and Lee-McCall methods. Prestressed concrete provides
Prestressed concrete structures and its applications By Mukesh Singh GhuraiyaMukesh Singh Ghuraiya
1. What is Prestressed??
2. Principle of Prestressed
3. Method of prestressing
4. Prestressed concrete structures
5. Advantages/application of Prestressed concrete
6. Disadvantages of Prestressed concrete
7. Comparison of RCC and Prestressed Concrete Flat Slabs
A system of prestressing involves tensioning tendons and securing them firmly to concrete. There are two main types: pre-tensioning and post-tensioning. Pre-tensioning involves pulling tendons tight between anchored abutments before concrete is poured. The Hoyer or long-line pre-tensioning system uses bulkheads to stretch wires over which molds are placed for concrete pouring. The Freyssinet system was the first post-tensioning method, using a cable of high-strength wires grouted into a duct within the concrete beam. Wires are anchored using conical plugs pushed into holes in concrete cylinders after jacking. The Magnel Blaton system tensions wires in pairs using sandwich plates
Prestressed concrete is concrete that is placed under compression using tensioned steel strands, cables, or bars. This is done through either pre-tensioning or post-tensioning. In pre-tensioning, the steel components are tensioned before the concrete is poured, while in post-tensioning, the steel components are tensioned after the concrete has hardened. Prestressed concrete provides benefits over reinforced concrete like lower construction costs, thinner structural elements, and longer spans between supports.
Pre stressed concrete- modular construction technologyAnjith Augustine
This document provides an overview of pre-stressed concrete, including its history, types (pre-tensioning and post-tensioning), materials, applications, advantages, and tensioning devices. Some key points include: pre-stressed concrete was developed in the 1930s-1940s and the first pre-stressed concrete bridge was built in India in 1948; it uses high-strength steel tendons to put concrete under compression and improve its tensile strength; common applications include bridges, buildings, and other structures; and advantages are increased strength, reduced cracking, and lighter/thinner designs.
This document discusses column jacketing, which is a method of retrofitting and strengthening existing columns. It involves adding reinforced concrete, steel, or fiber-reinforced polymer around the column. The key steps are preparing the column surface, adding shear keys and reinforcement, applying a bonding agent, and casting the new concrete or installing the jacket. Column jacketing increases the strength and seismic capacity of the column. It improves confinement and increases axial, shear, and foundation load capacity without significant weight addition.
Prestressed concrete combines high-strength concrete and high-strength steel in an active manner by tensioning steel tendons and holding them against the concrete, putting it into compression. This transforms concrete from a brittle to a more elastic material. It allows for optimal use of each material's properties and better behavior under loads. Prestressed concrete was pioneered in the 1930s and its use has expanded, finding applications in bridges and other structures. Common methods are pretensioning and post-tensioning, using various tendon types, with bonded or unbonded configurations. Tensioning is done using mechanical, hydraulic, electrical or chemical devices.
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.
This document discusses prestressed concrete, which uses tensioned steel cables or bars to put concrete members into compression and increase their strength. It describes three main methods: pre-tensioned concrete where the steel is tensioned before the concrete is cast; bonded post-tensioned concrete where steel is tensioned after casting to compress the concrete; and unbonded post-tensioned concrete where greased steel is used to allow individual adjustment. Applications include buildings, bridges, nuclear reactors and earthquake resistant structures. Advantages are lower costs, thinner members, and increased spans.
The document provides information on methods of prestressing in concrete, including pretensioning and post-tensioning. It discusses:
- Pretensioning involves stressing steel tendons before the concrete is cast around them.
- Post-tensioning involves stressing steel tendons after the concrete has cured using jacks, then grouting the voids.
- Both methods put the concrete in compression and increase its strength and durability compared to conventional reinforced concrete.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression and improve its tensile strength. There are two main methods - pre-tensioning and post-tensioning. Pre-tensioning tensions the strands before the concrete is poured, while post-tensioning tensions strands inside ducts after the concrete has cured. This compression counteracts tensile and flexural stresses from loads to reduce cracking and increase strength, allowing pre-stressed concrete to be lighter and more durable than reinforced concrete. It is commonly used in bridges, buildings, tanks, and other structures.
This document summarizes a seminar presentation on self-healing concrete given by students at VVP Polytechnic in Solapur, India under the guidance of Prof. Sathe. The presentation covered the definition, necessity, working mechanism using bacteria, tests conducted, comparison to traditional concrete, advantages like crack resistance and corrosion prevention, and applications. It discussed how bacteria and nutrients added to the concrete mix allow cracks to heal by producing limestone to fill the cracks when exposed to air and water.
Prestressing Concept, Materilas and Prestressing SystemLatif Hyder Wadho
The document discusses prestressing concepts and materials used in prestressed concrete. It describes how prestressing applies an initial compressive stress to concrete prior to service loads to improve strength and durability. Common prestressing materials include high-strength steel strands/wires, which are assembled into tendons and anchored internally or externally before or after concrete casting for pre-tensioning or post-tensioning. Grout is also discussed for transmitting stress between steel and concrete.
This document discusses prestressed concrete and provides details on:
- The definition and principle of prestressing concrete by applying compression prior to external loads
- Common prestressing methods like hydraulic, mechanical, electrical, and chemical prestressing
- Tests conducted on prestressed concrete components like post-tensioned splices and cast-in-place splices
- Advantages of prestressed concrete like reduced materials and increased strength
- Applications in bridges, buildings, water tanks, and more
- A case study on widening the Harrods Creek Arch Bridge using prestressed concrete
Diaphragm wall: Construction and DesignUmer Farooq
The document discusses diaphragm walls, which are concrete or reinforced concrete walls constructed below ground using a slurry-supported trench method. Diaphragm walls can reach depths of 150 meters and widths of 0.5-1.5 meters. They are constructed using tremie installation or pre-cast concrete panels. Diaphragm walls are suitable for urban construction due to their quiet installation and lack of vibration. The document discusses different types of diaphragm walls based on materials and functions, and provides details on their design, construction process, and material requirements.
Deflection & cracking of RC structure(limit state method)gudtik
This document summarizes structural design considerations for deflection and cracking in reinforced concrete beams. It discusses:
1) How deflection occurs when a structure carries a load and guidelines for limiting deflection to prevent issues.
2) How cracking develops in concrete when tensile strength is exceeded from beam deflection.
3) Codal provisions for maximum allowable crack widths depending on exposure conditions.
4) Methods for controlling crack widths, including bar spacing and calculating crack widths.
5) Codal provisions for limiting span-to-depth ratios to control deflections.
6) How to calculate short-term and long-term deflections, including effects of creep and shrinkage.
The document discusses reinforced earth walls, which combine earth and linear reinforcing strips to bear large tensile stresses. It describes how Henri Vidal came up with the concept while trying to build a reinforced sandcastle. The key components of reinforced earth walls are the soil, which is strong in compression, reinforcement like steel or concrete that is strong in tension, and a skin or facing to retain the soil. The document outlines design considerations for reinforced earth retaining walls, including checking external stability as a whole structure and internal stability of reinforcement layers.
The document discusses composite construction using precast prestressed concrete beams and cast-in-situ concrete. It describes how the two elements act compositely after the in-situ concrete hardens. Composite beams can be constructed as either propped or unpropped. Propped construction involves supporting the precast beam during casting to relieve it of the wet concrete weight, while unpropped construction allows stresses to develop under self-weight. Design and analysis of composite beams involves calculating stresses and deflections considering composite action. Differential shrinkage between precast and in-situ concrete also induces stresses.
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.
Cable Layout, Continuous Beam & Load Balancing MethodMd Tanvir Alam
This document provides information on cable layout and load balancing methods for prestressed concrete beams. It discusses layouts for simple, continuous, and cantilever beams. For simple beams, it describes layouts for pretensioned and post-tensioned beams, including straight, curved, and bent cable configurations. It also compares the load carrying capacities of simple and continuous beams. The document concludes by explaining the load balancing method for design, using examples of how to balance loads in simple, cantilever, and continuous beam configurations.
Deep foundations are used when the bearing stratum is located at a significant depth below the surface. The most common types of deep foundations are pile foundations, cofferdams, and caisson foundations. Pile foundations support structures using vertical piles that transfer loads either through end bearing or skin friction. Piles can be made of timber, concrete, steel, or a composite. Cofferdams are temporary structures used to exclude water from a construction site to allow work below the water level. Common types include earthfill, rockfill, single-walled, and cellular cofferdams. Caissons are watertight structures that become part of the permanent foundation. Types are open caissons, box caissons
The document discusses the design of footings for structures. It begins by explaining that footings are needed to transfer structural loads from members made of materials like steel and concrete to the underlying soil. It then describes different types of shallow and deep foundations, including spread, strap, combined, and raft footings. The document provides details on designing isolated and combined footings to resist vertical loads and moments based on provisions in IS 456. It also discusses wall footings and combined footings that support multiple columns. In summary, the document covers the purpose of footings, various footing types, and design of isolated and combined footings.
The document discusses limit state design of reinforced concrete structures. It introduces limit states as conditions where the structure becomes unfit for use, including limit states of strength and serviceability. Limit state design involves characterizing loads and resistances as random variables and using partial safety factors on loads and resistances to achieve a target reliability. The document outlines the general principles of limit state design according to Indian Standard code IS 800, including defining actions, factors governing strength limits, and serviceability limits related to deflection, vibration and durability.
This document provides guidance on the design of lacing and battens for built-up compression members. It discusses the key design considerations and calculations for both single and double lacing systems, including the angle of inclination, slenderness ratio, effective lacing length, bar width and thickness. Similar guidelines are given for battens, covering spacing, thickness, effective depth, transverse shear and overlap. The document also includes an example problem on designing a slab foundation for a column with given load and material properties.
The document is a project report for the preliminary design of a water treatment plant. It includes an index, acknowledgements, objectives, introduction and survey sections. The structural elements section describes the main components of the water treatment plant, including an aerator, alum dosing tanks, coagulation and sedimentation tank, rapid gravity filters, chlorinator, clear water reservoir and main distribution tank. The design specifications section provides specifications for designing components like the pre-sedimentation tank.
Prestressed concrete is a combination of steel and concrete that uses compressive stresses applied during construction to oppose tensile stresses that occur in use. There are three main types: pre-tensioned concrete uses steel tendons tensioned before concrete is placed; bonded post-tensioned concrete uses unstressed steel placed then tensioned after curing; and unbonded post-tensioned concrete provides freedom of movement between steel and concrete. Pre-tensioned concrete requires molds that can resist internal forces and calculations to account for losses over time. Prestressed concrete provides benefits like reduced cracking and corrosion, higher strength, and more economical construction for bridges compared to steel.
This document provides an overview of prestressed concrete presented by Sayan Saha from Silliguri Institute of Technology. It introduces prestressed concrete as a method to overcome concrete's weakness in tension. The principle is that compressive stresses induced in concrete by high-strength steel tendons before loading will balance tensile stresses during use. There are two main methods: pre-tensioning where tendons are stressed before concreting, and post-tensioning where tendons are stressed after concrete curing. Advantages include reduced member thickness, deflections, weight, and cracking, while disadvantages require specialized equipment, technical knowledge, and skilled labor.
This document discusses prestressed concrete, including:
- The basic concepts of prestressing including using metal bands, pre-tensioned spokes, and introducing stresses to counteract external loads.
- Design concepts like losses in prestressing structures from elastic shortening, creep, shrinkage, relaxation, friction, and anchorage slip.
- Provisions for prestressing in the Indian Road Congress Bridge Code and Indian Standard Code.
- Construction aspects like casting of girders, post-tensioning work, and load testing of structures.
This document discusses prestressed concrete, which uses tensioned steel cables or bars to put concrete members into compression and increase their strength. It describes three main methods: pre-tensioned concrete where the steel is tensioned before the concrete is cast; bonded post-tensioned concrete where steel is tensioned after casting to compress the concrete; and unbonded post-tensioned concrete where greased steel is used to allow individual adjustment. Applications include buildings, bridges, nuclear reactors and earthquake resistant structures. Advantages are lower costs, thinner members, and increased spans.
The document provides information on methods of prestressing in concrete, including pretensioning and post-tensioning. It discusses:
- Pretensioning involves stressing steel tendons before the concrete is cast around them.
- Post-tensioning involves stressing steel tendons after the concrete has cured using jacks, then grouting the voids.
- Both methods put the concrete in compression and increase its strength and durability compared to conventional reinforced concrete.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression and improve its tensile strength. There are two main methods - pre-tensioning and post-tensioning. Pre-tensioning tensions the strands before the concrete is poured, while post-tensioning tensions strands inside ducts after the concrete has cured. This compression counteracts tensile and flexural stresses from loads to reduce cracking and increase strength, allowing pre-stressed concrete to be lighter and more durable than reinforced concrete. It is commonly used in bridges, buildings, tanks, and other structures.
This document summarizes a seminar presentation on self-healing concrete given by students at VVP Polytechnic in Solapur, India under the guidance of Prof. Sathe. The presentation covered the definition, necessity, working mechanism using bacteria, tests conducted, comparison to traditional concrete, advantages like crack resistance and corrosion prevention, and applications. It discussed how bacteria and nutrients added to the concrete mix allow cracks to heal by producing limestone to fill the cracks when exposed to air and water.
Prestressing Concept, Materilas and Prestressing SystemLatif Hyder Wadho
The document discusses prestressing concepts and materials used in prestressed concrete. It describes how prestressing applies an initial compressive stress to concrete prior to service loads to improve strength and durability. Common prestressing materials include high-strength steel strands/wires, which are assembled into tendons and anchored internally or externally before or after concrete casting for pre-tensioning or post-tensioning. Grout is also discussed for transmitting stress between steel and concrete.
This document discusses prestressed concrete and provides details on:
- The definition and principle of prestressing concrete by applying compression prior to external loads
- Common prestressing methods like hydraulic, mechanical, electrical, and chemical prestressing
- Tests conducted on prestressed concrete components like post-tensioned splices and cast-in-place splices
- Advantages of prestressed concrete like reduced materials and increased strength
- Applications in bridges, buildings, water tanks, and more
- A case study on widening the Harrods Creek Arch Bridge using prestressed concrete
Diaphragm wall: Construction and DesignUmer Farooq
The document discusses diaphragm walls, which are concrete or reinforced concrete walls constructed below ground using a slurry-supported trench method. Diaphragm walls can reach depths of 150 meters and widths of 0.5-1.5 meters. They are constructed using tremie installation or pre-cast concrete panels. Diaphragm walls are suitable for urban construction due to their quiet installation and lack of vibration. The document discusses different types of diaphragm walls based on materials and functions, and provides details on their design, construction process, and material requirements.
Deflection & cracking of RC structure(limit state method)gudtik
This document summarizes structural design considerations for deflection and cracking in reinforced concrete beams. It discusses:
1) How deflection occurs when a structure carries a load and guidelines for limiting deflection to prevent issues.
2) How cracking develops in concrete when tensile strength is exceeded from beam deflection.
3) Codal provisions for maximum allowable crack widths depending on exposure conditions.
4) Methods for controlling crack widths, including bar spacing and calculating crack widths.
5) Codal provisions for limiting span-to-depth ratios to control deflections.
6) How to calculate short-term and long-term deflections, including effects of creep and shrinkage.
The document discusses reinforced earth walls, which combine earth and linear reinforcing strips to bear large tensile stresses. It describes how Henri Vidal came up with the concept while trying to build a reinforced sandcastle. The key components of reinforced earth walls are the soil, which is strong in compression, reinforcement like steel or concrete that is strong in tension, and a skin or facing to retain the soil. The document outlines design considerations for reinforced earth retaining walls, including checking external stability as a whole structure and internal stability of reinforcement layers.
The document discusses composite construction using precast prestressed concrete beams and cast-in-situ concrete. It describes how the two elements act compositely after the in-situ concrete hardens. Composite beams can be constructed as either propped or unpropped. Propped construction involves supporting the precast beam during casting to relieve it of the wet concrete weight, while unpropped construction allows stresses to develop under self-weight. Design and analysis of composite beams involves calculating stresses and deflections considering composite action. Differential shrinkage between precast and in-situ concrete also induces stresses.
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.
Cable Layout, Continuous Beam & Load Balancing MethodMd Tanvir Alam
This document provides information on cable layout and load balancing methods for prestressed concrete beams. It discusses layouts for simple, continuous, and cantilever beams. For simple beams, it describes layouts for pretensioned and post-tensioned beams, including straight, curved, and bent cable configurations. It also compares the load carrying capacities of simple and continuous beams. The document concludes by explaining the load balancing method for design, using examples of how to balance loads in simple, cantilever, and continuous beam configurations.
Deep foundations are used when the bearing stratum is located at a significant depth below the surface. The most common types of deep foundations are pile foundations, cofferdams, and caisson foundations. Pile foundations support structures using vertical piles that transfer loads either through end bearing or skin friction. Piles can be made of timber, concrete, steel, or a composite. Cofferdams are temporary structures used to exclude water from a construction site to allow work below the water level. Common types include earthfill, rockfill, single-walled, and cellular cofferdams. Caissons are watertight structures that become part of the permanent foundation. Types are open caissons, box caissons
The document discusses the design of footings for structures. It begins by explaining that footings are needed to transfer structural loads from members made of materials like steel and concrete to the underlying soil. It then describes different types of shallow and deep foundations, including spread, strap, combined, and raft footings. The document provides details on designing isolated and combined footings to resist vertical loads and moments based on provisions in IS 456. It also discusses wall footings and combined footings that support multiple columns. In summary, the document covers the purpose of footings, various footing types, and design of isolated and combined footings.
The document discusses limit state design of reinforced concrete structures. It introduces limit states as conditions where the structure becomes unfit for use, including limit states of strength and serviceability. Limit state design involves characterizing loads and resistances as random variables and using partial safety factors on loads and resistances to achieve a target reliability. The document outlines the general principles of limit state design according to Indian Standard code IS 800, including defining actions, factors governing strength limits, and serviceability limits related to deflection, vibration and durability.
This document provides guidance on the design of lacing and battens for built-up compression members. It discusses the key design considerations and calculations for both single and double lacing systems, including the angle of inclination, slenderness ratio, effective lacing length, bar width and thickness. Similar guidelines are given for battens, covering spacing, thickness, effective depth, transverse shear and overlap. The document also includes an example problem on designing a slab foundation for a column with given load and material properties.
The document is a project report for the preliminary design of a water treatment plant. It includes an index, acknowledgements, objectives, introduction and survey sections. The structural elements section describes the main components of the water treatment plant, including an aerator, alum dosing tanks, coagulation and sedimentation tank, rapid gravity filters, chlorinator, clear water reservoir and main distribution tank. The design specifications section provides specifications for designing components like the pre-sedimentation tank.
Prestressed concrete is a combination of steel and concrete that uses compressive stresses applied during construction to oppose tensile stresses that occur in use. There are three main types: pre-tensioned concrete uses steel tendons tensioned before concrete is placed; bonded post-tensioned concrete uses unstressed steel placed then tensioned after curing; and unbonded post-tensioned concrete provides freedom of movement between steel and concrete. Pre-tensioned concrete requires molds that can resist internal forces and calculations to account for losses over time. Prestressed concrete provides benefits like reduced cracking and corrosion, higher strength, and more economical construction for bridges compared to steel.
This document provides an overview of prestressed concrete presented by Sayan Saha from Silliguri Institute of Technology. It introduces prestressed concrete as a method to overcome concrete's weakness in tension. The principle is that compressive stresses induced in concrete by high-strength steel tendons before loading will balance tensile stresses during use. There are two main methods: pre-tensioning where tendons are stressed before concreting, and post-tensioning where tendons are stressed after concrete curing. Advantages include reduced member thickness, deflections, weight, and cracking, while disadvantages require specialized equipment, technical knowledge, and skilled labor.
This document discusses prestressed concrete, including:
- The basic concepts of prestressing including using metal bands, pre-tensioned spokes, and introducing stresses to counteract external loads.
- Design concepts like losses in prestressing structures from elastic shortening, creep, shrinkage, relaxation, friction, and anchorage slip.
- Provisions for prestressing in the Indian Road Congress Bridge Code and Indian Standard Code.
- Construction aspects like casting of girders, post-tensioning work, and load testing of structures.
This document discusses prestressed concrete. It begins with a definition of prestressing as applying an initial load to a structure to counteract stresses during its service period. It then provides a brief history of prestressing including early attempts using metal bands on barrels and tensioning bicycle wheel spokes. The document outlines different materials and hardware used in prestressing including tendons, strands, wires, bars and anchoring devices. It describes various prestressing techniques such as pretensioning, posttensioning, bonded vs unbonded tendons. Applications of prestressed concrete include bridges, buildings, tanks, and more. Advantages are listed as increased strength, reduced cracking and deformation, while limitations include higher costs and need for skilled construction techniques.
The document provides an overview of prestressed concrete structures including:
- Definitions of prestressing where internal stresses counteract external loads.
- The key terminology used including tendons, anchorage, pretensioning vs post-tensioning.
- The materials used including cement, concrete, and steel types.
- The stages of loading and advantages of prestressing over reinforced concrete.
- Details of pretensioning and post-tensioning systems including equipment, processes, and differences between the two methods.
This document provides an introduction to prestressed concrete, including:
- Prestressing concrete involves applying an initial compressive load to counteract tensile stresses during use. Ancient examples include metal bands on wood.
- Prestressing provides advantages over reinforced concrete like reduced cracking, increased strength and stiffness, and suitability for precast construction.
- It describes prestressing materials, common systems like pre-tensioning and post-tensioning, and concepts in the analysis and design of prestressed concrete like stress conditions and load balancing.
Prestressed concrete is a structural material that allows for predetermined, engineering stresses to be placed in members to counteract the stresses that occur when they are subject to loading.
This document provides an introduction to prestressed concrete, including:
1) A prestressed concrete structure differs from reinforced concrete in applying an initial load to counteract stresses from use.
2) Prestressing concepts include transforming concrete to an elastic material, combining high strength steel with concrete, and load balancing.
3) Methods include pre-tensioning and post-tensioning, and materials include high strength steel tendons or bars, concrete, and grout.
This document summarizes a presentation on prestressed concrete. It begins with an introduction to prestressed concrete and how it overcomes weaknesses in concrete in tension. It then describes the principles of prestressing by inducing compressive stresses with high-strength tendons before loads are applied. The document compares reinforced concrete with prestressed concrete and describes the methods of pre-tensioning and post-tensioning. It provides examples of prestressed concrete structures like beams, bridges and discusses advantages like reduced size and increased spans as well as disadvantages like higher material costs.
This document discusses prestressed concrete. It begins with a brief introduction to prestressing, including its history. It then discusses materials and hardware used for prestressing, including tendons, strands, wires, and bars. The document outlines different types of prestressing such as pretensioning vs posttensioning. It also discusses applications of prestressed concrete such as in bridges, buildings, and water tanks. Finally, it covers advantages like increased strength and reduced cracking, and disadvantages like increased cost and need for skilled labor.
This document discusses prestressed concrete. It begins with a brief introduction to prestressing, including its history. It then discusses materials and hardware used for prestressing, including tendons, strands, wires, and bars. The document outlines different types of prestressing such as pretensioning vs posttensioning. It also discusses applications of prestressed concrete such as in bridges, buildings, and water tanks. Finally, it covers advantages like increased strength and reduced cracking, and disadvantages like increased cost and need for skilled labor.
this presentation has animations, play it in ms powerpoint as slideshow for better understanding.
this module includes
a) Introduction
b) Advantages and types of
pre-stressing
c) Pre-stressing systems
d) Materials for pre-stressing
E) PREREQUISITE OF SOM
This document provides information on a syllabus for a course on prestressed concrete. It outlines the course objectives which are to understand the principles, necessity, techniques, losses, and analysis and design of prestressed concrete members. The course outcomes are for students to acquire knowledge on the evolution of prestressing, prestressing techniques, and skills in analyzing and designing prestressed structural elements per code provisions. The syllabus then outlines 5 units that will be covered which include introduction, methods and systems, losses of prestress, flexure, shear, transfer of prestress, composite beams, and deflections. Relevant textbooks and codes are also listed.
Pre-stressed concrete was a major innovation that replaced conventional reinforced concrete, allowing for longer spans, higher impact resistance, and greater load capacity without tensile stresses. It involves casting concrete around high-strength steel that is placed under compression before use to counteract tensile stresses when in service. There are two main types: pre-tensioning applies tension before casting, while post-tensioning does so after casting, using ducts to hold the steel. Pre-stressed concrete enables more efficient structures through factory casting and reduced material needs.
Seismic Behavior Of Double Steel Plate Composite Wall Under Cyclic LoadingIRJET Journal
This document analyzes the seismic behavior of double steel plate composite walls (DSPCWs) under cyclic loading through finite element analysis. Six DSPCW models were developed varying the aspect ratio (length to width ratio) and tie stud spacing. Lower aspect ratios and smaller tie stud spacings improved the wall's energy dissipation, ductility, and resistance to strength and stiffness degradation under cyclic loads. The analysis found the aspect ratio and tie stud spacing significantly impacted the wall's hysteretic response, failure mechanism, strength deterioration, and stiffness. Walls with lower aspect ratios or smaller tie stud spacings exhibited greater seismic resistance and deformation capacity.
Prestressing Concept, Materials and Prestressing System - Section B, Group 1সাফকাত অরিন
This document provides an overview of prestressing concepts, materials, and systems. It discusses the basic concepts of prestressing including transforming concrete into an elastic material, combining high-strength steel with concrete, and achieving load balancing. The document describes the advantages and limitations of prestressing. It also summarizes the different types of prestressing in terms of the source of prestressing force, whether it is external or internal, pre-tensioned or post-tensioned, linear or circular, full or partial, and uniaxial, biaxial, or multiaxial. Finally, it discusses prestressing materials including concrete, aggregate, cement, water, admixtures, grout, and prestressing steel.
This document provides an outline for lectures on prestressed concrete, including basic concepts, materials, flexural analysis, design considerations, shear/torsion, loss of prestress over time, composite beams, and deflections. Key points covered include how prestressing controls cracking by applying compressive stresses to concrete before service loads; common prestressing methods of pre-tensioning and post-tensioning; estimating stresses in uncracked concrete beams using elastic theory; and accounting for various load stages in analysis and design.
This document provides an introduction to prestressed concrete, including:
1. The basic principles of prestressing concrete by applying compressive stresses that counteract tensile stresses from loads. This allows for smaller, more durable structures.
2. The two main methods are pre-tensioning, where strands are stressed before casting, and post-tensioning, where strands are tensioned after casting through ducts.
3. Common uses include precast beams, slabs, piles, and tanks, as well as in-situ construction like balanced cantilevers and segmental bridges. Design must account for losses in prestress over time from shrinkage, creep, and relaxation.
This document provides an introduction to prestressed concrete, including:
1. The basic principles of prestressing concrete by applying compressive stresses that counteract tensile stresses from loads. This allows for smaller member sizes.
2. The main advantages are smaller sections, reduced deflections, increased spans, and improved durability due to reduced cracking.
3. The two main methods are pre-tensioning, where strands are stressed before casting, and post-tensioning, where strands are tensioned after casting through ducts.
4. Uses include precast beams, slabs, piles, tanks, and bridges constructed with either precast or post-tensioned segments.
CONCRETE-ENCASED CFST BEAM-COLUMN JOINTS: A REVIEWIRJET Journal
This document reviews concrete-encased concrete-filled steel tubular (CFST) beam-column joints. It discusses how beam-column joints are the most seismically affected part of framed structures, so understanding their seismic performance is important. Concrete-encased CFST beam-column joints consist of a CFST core surrounded by reinforced concrete. The document reviews the properties and performance of these joints, including different types of connections, experimental investigations that have been conducted, and the results of one experimental program that tested seismic performance and found three main failure types. In summary, concrete-encased CFST beam-column joints demonstrate favorable seismic behavior and strength due to the composite action of the steel tube and concrete.
IRJET- Comparative Study on the Seismic Behaviour of RCC and Steel-Concrete C...IRJET Journal
This document presents a comparative study on the seismic behavior of reinforced concrete concrete (RCC) frame structures and steel-concrete composite frame structures. Five 20-story building models are analyzed: one RCC structure and four composite structures with different column and beam configurations. Parameters like time period, story displacement, drift ratio, base shear, etc. are extracted and compared for the structures under equivalent static and response spectrum analysis for seismic zones II and V. The results show that composite structures have higher time periods and displacements but lower drift ratios and base shears compared to the RCC structure. In particular, composite model 3 with rectangular concrete filled steel columns performed better with smaller displacements and drift ratios.
This study Examines the Effectiveness of Talent Procurement through the Imple...DharmaBanothu
In the world with high technology and fast
forward mindset recruiters are walking/showing interest
towards E-Recruitment. Present most of the HRs of
many companies are choosing E-Recruitment as the best
choice for recruitment. E-Recruitment is being done
through many online platforms like Linkedin, Naukri,
Instagram , Facebook etc. Now with high technology E-
Recruitment has gone through next level by using
Artificial Intelligence too.
Key Words : Talent Management, Talent Acquisition , E-
Recruitment , Artificial Intelligence Introduction
Effectiveness of Talent Acquisition through E-
Recruitment in this topic we will discuss about 4important
and interlinked topics which are
Cricket management system ptoject report.pdfKamal Acharya
The aim of this project is to provide the complete information of the National and
International statistics. The information is available country wise and player wise. By
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We have designed & manufacture the Lubi Valves LBF series type of Butterfly Valves for General Utility Water applications as well as for HVAC applications.
A high-Speed Communication System is based on the Design of a Bi-NoC Router, ...DharmaBanothu
The Network on Chip (NoC) has emerged as an effective
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issues within the router's memory unit and proposes an enhanced
memory structure. To achieve efficient data transfer, FIFO buffers
are implemented in distributed RAM and virtual channels for
FPGA-based NoC. The project introduces advanced FIFO-based
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in a Bi-directional NoC (Bi-NoC) configuration. The primary
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FIFO internal structure. To further improve data transfer speed,
a Bi-NoC with a self-configurable intercommunication channel is
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guaranteed throughput, predictable latency, and equitable
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Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
This is an overview of my current metallic design and engineering knowledge base built up over my professional career and two MSc degrees : - MSc in Advanced Manufacturing Technology University of Portsmouth graduated 1st May 1998, and MSc in Aircraft Engineering Cranfield University graduated 8th June 2007.
Covid Management System Project Report.pdfKamal Acharya
CoVID-19 sprang up in Wuhan China in November 2019 and was declared a pandemic by the in January 2020 World Health Organization (WHO). Like the Spanish flu of 1918 that claimed millions of lives, the COVID-19 has caused the demise of thousands with China, Italy, Spain, USA and India having the highest statistics on infection and mortality rates. Regardless of existing sophisticated technologies and medical science, the spread has continued to surge high. With this COVID-19 Management System, organizations can respond virtually to the COVID-19 pandemic and protect, educate and care for citizens in the community in a quick and effective manner. This comprehensive solution not only helps in containing the virus but also proactively empowers both citizens and care providers to minimize the spread of the virus through targeted strategies and education.
2. What is Pre-stressing ?
Pre-stressing is a technique to eliminate tension in the system, which is very weak in
tension but strong in compression.
Examples:
(1) Force-fitting of metal bands on wooden barrels-
Metal bands: Initial hoop compression
Filling of Liquid: hoop tension
Figure-1. Wooden Barrel
3. Contd…
(2) Pre-tensioning the spokes in a bicycle wheel
Spokes: Initially Pre-tensioned
LL+DL : Compression at working condition
Tension+ Compession= residual tension
Figure-2. Bicycle Wheel
4. What is Pre-stressed Concrete ?
Concrete in which reinforcing steel bars are stretched and anchored to compress it
and thus increase its resistance to stress by eliminating tensile stress.
Basic steps as shown in fig.
1. Strands/tendons are stressed by Jack
2. Concreting is done
3. Pre-stress is transferred to section.
Figure-3. Pre-stress concrete
5. Types of Pre-stress concrete
1. Pre-Tensioned
Profile of tendons is
fixed.
Strands or high tensile
tendons are pre-stressed
by Jacks.
Concrete is placed and
leave for hardening.
Pre-stress is Transferred
to concrete section.
2. Bonded Post-tensioned
HDPE Ducts are placed through
ordinary reinforcement.
Fixing the profile of ducts, then
tendons are inserted into ducts.
Concrete is placed and allowed to
get strength.
Tendons are stressed at different
stages (i.e. Transfer, Working)
and Ducts are filled with cement-
grout.
3. Un-bonded Post-tensioned
HDPE Ducts are placed through
ordinary reinforcement.
Fixing the profile of ducts, then
tendons are inserted into ducts.
Concrete is placed and allowed
to get strength
Strands are stressed according
to stages and ducts are remained
empty.
6. Materials for pre-stress concrete
Cement:
(1) Ordinary Portland cement conforming to IS269
(2) Portland slag cement conforming to IS455. But the slag content should not be more than 50% by weight.
(3) Rapid hardening Portland cement conforming to IS8041.
Concrete:
(1)Pre-stress concrete requires concrete, which has a high compressive strength reasonably early age.
(2) Minimum grade of concrete, M30 for post-tensioned and M40 for pre-tensioned.
Steel:
(1) High strength(1600 to 2000 N/mm2) steel contains: 0.7 to 0.8% carbons, 0.6% manganese, 0.1% silica.
(2) Plain hard-drawn steel wire conforming to IS1785 (Part-I & Part-III) and
7. Tensioning Devices
Mechanical Devices
(1) Mechanical mechanisms are used to stress tendons, like-Lever arm transmission, geared transmission
in conjunction with pulley blocks, screw jacks with or without gear devices.
Hydraulic Devices
(1) It is the simplest means for producing large pre-stressing force, based on fluid pressure property.
Electrical Devices
(1) In thermo-pre-stressing method, wires are electrically heated and anchored in the mould.
Chemical Devices
(1) Expanding cements are used and the degree of expansion is controlled by varying the curing condition.
8. Anchoring systems for tendons
(1) Wedge action producing a frictional grip.
Wedge type anchoring is shown in fig.
(2) Direct bearing from the rivet or bolt heads.
(3) Looping the wire around the concrete.
Figure-4. Wedge type anchorage
9. Analysis of Pre-stress Concrete(Flexure)
Case-A: Concentric Tendon ( eccentricity is zero)
Where, No LL & DL in above Case-A, If LL & DL are present then simple bending stress diagram can be
superimposed to get resultant.
Figure-5. Concentric pre-stressing
10. Contd…
Case-B: Eccentric Tendon
Where, No LL & DL in above Case-B, If LL & DL are present then simple bending stress diagram can be
superimposed to get resultant.
Figure-6. Eccentric pre-stressing
12. Stress losses in pre-stress
1. Pre-tensioned
Elastic deformation of concrete
Relaxation of stress in steel
Shrinkage of concrete
Creep of concrete
2. Post-tensioned
Losses Can be or can not be due
elastic deformation of concrete
Relaxation of stress in steel
Shrinkage of concrete
Creep of concrete
Friction losses
Anchorage slip Loss
13. Brief Explanation about pre-stress losses
1. Loss due to elastic deformation:
Strain in concrete at the level of steel =
fc
Ec
Stress in steel corresponding to this strain =
fc
Ec
∙ 𝐸𝑠 ; Loss of stress in steel = m.fc
2. Loss due to shrinkage of concrete:
𝜀cs = total residual shrinkage strain = 300× 10-6 for pre-tensioning.
=
200×10−6
𝑙𝑜𝑔10 (𝑡+2)
for post-tensioning
Loss of stress due to shrinkage = Es. 𝜀cs
14. Contd…
3. Loss due to creep of concrete:
(a)Ultimate Creep strain method:- loss of stress due to creep= 𝜀cc.fc.Es
(b) Creep Coefficient Method:- Creep coefficient, ∅ =
Creep strain
Elastic strain
=
𝜀 𝑐
𝜖 𝑒
loss of stress in steel = 𝜀c.Es = ∅. 𝜀e.Es = ∅
𝑓𝑐
𝐸 𝑐
. 𝐸𝑠
4. Loss due to relaxation of stress in steel:
IS :1343-2012 recommends a value varying from 0 to 90 N/mm2 for stress in wires
varying from 0.5 fpu from 0.8 fpu.
15. Contd…
5. Loss of stress due to friction and wobble:
It depends on wobble and friction coefficient, Cable profile.
Px = Po 𝑒−(𝜇𝛼+𝑘𝑥) ; loss in stress= P0-Px
6. Loss due to Anchorage slip:
Anchorage slip, ∆=
𝑃𝐿
𝐴𝐸𝑠
Loss of stress due to anchorage slip =
𝐸𝑠.∆
𝐿
16. Why Pre-stress Concrete ?
Pre-stress Concrete
Steel plays active role with or without external load.
High Shear & fatigue resistance
load balancing mechanism very less deflection
More durable because of high grade of concrete
P.S.C section dimensions is less than R.C.C
Reduction 30% in concrete and 60% in steel.
Ordinary R.C.C
Steel plays a passive role, depends on loads.
Low Shear & fatigue resistance
More deflection, and tension cracks occur
Less durable tension cracks, low grade
Large R.C.C section required for large span
length Uneconomical and huge DL.
17. Applications of pre-stress concrete
Buildings:
1. Precast pre-stressed concrete systems are successfully applied to
high-rise buildings even in high-seismicity regions.
2. It is equivalent to steel-encased reinforced concrete buildings in
terms of structural and economical performance
Figure-8. Sydney opera house
Figure-9. Post-tensioned slab
18. Contd…
Electric Poles:
1. Pre-stresss concrete electrical
Poles are inevitably less costly and
more economically maintainable
than the conventional steel poles.
2. Galvanised wire is fixed inside
the mould for earthing following
which a right proportion of
concrete mix is poured.
Figure-10. Electric pre-tensioned pole
19. Contd…
Railway Sleeper
the pre-stress concrete
sleepers (or railroad ties) are
principally designed in
order to carry wheel loads
from the rails to the ground.
design takes into account
static and dynamic loading
conditions.
20. Contd…
Water Tank
Pre-stressed concrete tank which can
be used for storing the high
temperature liquid.
Main components are-Tank floor,
Tank wall, Roof slab.
To reduce hoop stress, compressive
pre-stress is applied.
Figure-11. Pre-stress water tank/vessel
21. Contd…
Post-Tensioned Bridge
High-strength steel tendons are
positioned in ducts or sleeves before
the concrete is placed.
Once the concrete has gained
strength, tension is applied, pulling
the tendons and anchoring them
against the outer edges of the
concrete, before service loads are
applied.
Figure-12. Post-tension box girder
22. Contd…
Precast/Pre-stress Stadium
Design flexibility, inherent cost savings,
speed of construction, durability and
aesthetic qualities, precast/Pre-stress
concrete is a good choice.
Many components of stadium which can be
constructed using pre-stressed concrete-
Stadia seating units, Columns, Inverted T
beams, rectangular beams, L beams, Stairs,
Solid slabs.
Figure-13. Precast/ pre-stress based Stadium
23. Conclusion
P.S.C is an effective solution for eliminating tension crack in concrete.
Pre-stress concrete lever arm keeps changing with loading stages hence long
service life.
Precast and pre-stress concrete is the most powerful technology to construct
cost effective and more durable civil engineering structure with longer life span.
Post-tensioned technique now a days long span segmental bridge are being
constructed all over the world.
P.S.C sections are more brittle and less fire resistance, and needs new pre-
stressing technology.
24. References
1) American Concrete Institute, "CT-13: ACI Concrete Terminology", “Post-tensioned
concrete”, American Concrete Institute. Farmington Hills, Michigan US:ACI, Retrieved
25, August 2016.
2) “State of The Art: Research And Application Of Precast / Prestressed Concrete Systems
In Indonesia”, The 14th World Conference on Earthquake Engineering October 12-17,
2008, Beijing, China.
3) P B Morice, C & C A, June 17, 2015 “The Analysis Of Prestressed Concrete Structures
And The Application Of Recent Research” Paper No 51.
4) Gasparini, D and da Porto, F (2003). “Prestressing of 19th century wood and iron truss
bridges in the US”, Proceedings of the First International Congress on Construction
History.
5) N Krishna Raju, Professor of MS Ramaiah Institute of Technology, “Prestress
Concrete”, 4th Edition, 2007.
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