This document provides an overview of pre-stressed concrete, including:
1. It defines pre-stressed concrete as concrete in which internal stresses are introduced to counteract stresses from external loads.
2. It discusses the materials used - steel wires, strands, tendons, and cables - and whether they are bonded or unbonded.
3. It compares pre-stressed concrete and reinforced concrete, noting differences in stress levels, deflections, shear resistance, fatigue resistance, and economics.
Comparison of reinforced concrete and prestressed concreteSpice Shuvo
This document compares reinforced concrete and prestressed concrete. Reinforced concrete uses steel reinforcement embedded in concrete to increase its tensile strength. Prestressed concrete applies compression to concrete before loading to counteract tensile stresses when in use. For construction, reinforced concrete requires steel bars and formwork while prestressed concrete uses steel tendons stressed after the concrete reaches strength. Prestressed concrete allows for thinner sections, reduced self-weight, and less deflection compared to reinforced concrete. However, it requires higher quality materials and specialized equipment. In summary, the document outlines the key differences in material composition and behavior between the two composite concrete materials.
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.
A COMPOSITE STRUCTURE AND A RCC STRUCTURE ARE CONSIDERED FOR COMPARATIVE STUDY OF G+9 STORY COMMERCIAL BUILDING WHICH IS SITUATED IN HYDERABAD, INDIA EARTHQUAKE ZONE 2 AND FOR EARTHQUAKE LOADING. A THREE DIMENSIONAL MODELLING AND ANALYSIS OF BOTH THE STRUCTURES ARE CARRIED OUT WITH THE HELP OF ETABS SOFTWARE. THE ABOVE STUDY DEALS WITH THE COMPARISON OF ANALYTICAL RESULTS OF RCC STRUCTURE AND COMPOSITE STRUCTURE UNDER THE EFFECT OF STATIC AND DYNAMIC LOADS. THE ANALYSIS AND BEHAVIOR OF THE COMPOSITE STRUCTURE AS WELL AS THE RCC STRUCTURE ARE EXAMINED. THE COMPOSITE STRUCTURE PROVED TO BE MORE ECONOMICAL AND RELIABLE THAN COMPARED TO A RCC STRUCTURE DESIGNED FOR SIMILAR AND LOADING CONDITIONS.
Composite Construction Method for Engineering and ArchitectureMimi Alguidano
Composite construction uses two materials together to utilize each material's strengths. It examines problems with steel-concrete beams, including concrete placement order and deflection monitoring. New approaches include beam-column systems and air ducts in box girders. Other composites include timber-concrete slabs and steel-timber trusses.
Composite construction is beneficial because concrete resists compression well and steel resists tension well. Joining them results in an efficient, lightweight design with construction speed benefits. It allows for reduced floor depths and foundation sizes.
The benefits of composite construction include speed, performance, and value. Steel erection is fast and prefabricated decks provide stiffness when concrete cures. Concrete also protects
The Structural Behaviour of Concrete Filled Steel Tubular columnsIRJET Journal
This document describes a study comparing the structural behavior of concrete-filled steel tubular columns made with different steel materials through numerical analysis and experimental testing. Six column specimens were tested - two each made with stainless steel, mild steel, and cold-formed steel tubes. Both short and long columns were analyzed. The numerical analysis found that stainless steel columns had the highest load-carrying capacity. The experimental results supported this, with stainless steel columns outperforming the other materials. There was good agreement between the numerical and experimental load values, with errors generally below 5%. The study concluded that stainless steel provided the best performance for concrete-filled steel tubular columns subjected to axial loads.
Prestressed concrete is concrete in which internal stresses are introduced to counteract external loads. Tendons are stretched elements that impart prestress, and anchorage devices enable the tendons to impart and maintain prestress. There are two main methods - pretensioning, where tendons are tensioned before concrete is cast, and post-tensioning, where tendons are tensioned against hardened concrete. Prestressed concrete uses high-strength materials like cement, concrete, and steel tendons or strands to achieve its compressive strength and durability advantages over reinforced concrete.
This document discusses steel-concrete composite construction. It describes shear connectors, which provide composite action between steel beams and concrete slabs. There are three main types of shear connectors: rigid connectors made of steel bars or angles that resist shear through bearing pressure; flexible stud connectors that bend and fail through yielding; and bond-type connectors that rely on bond and anchoring. The document discusses the design of shear connectors according to Indian codes IRC 22-1986 and IS 11384-1985, providing methods to calculate the design strength of shear connectors.
Comparison of reinforced concrete and prestressed concreteSpice Shuvo
This document compares reinforced concrete and prestressed concrete. Reinforced concrete uses steel reinforcement embedded in concrete to increase its tensile strength. Prestressed concrete applies compression to concrete before loading to counteract tensile stresses when in use. For construction, reinforced concrete requires steel bars and formwork while prestressed concrete uses steel tendons stressed after the concrete reaches strength. Prestressed concrete allows for thinner sections, reduced self-weight, and less deflection compared to reinforced concrete. However, it requires higher quality materials and specialized equipment. In summary, the document outlines the key differences in material composition and behavior between the two composite concrete materials.
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.
A COMPOSITE STRUCTURE AND A RCC STRUCTURE ARE CONSIDERED FOR COMPARATIVE STUDY OF G+9 STORY COMMERCIAL BUILDING WHICH IS SITUATED IN HYDERABAD, INDIA EARTHQUAKE ZONE 2 AND FOR EARTHQUAKE LOADING. A THREE DIMENSIONAL MODELLING AND ANALYSIS OF BOTH THE STRUCTURES ARE CARRIED OUT WITH THE HELP OF ETABS SOFTWARE. THE ABOVE STUDY DEALS WITH THE COMPARISON OF ANALYTICAL RESULTS OF RCC STRUCTURE AND COMPOSITE STRUCTURE UNDER THE EFFECT OF STATIC AND DYNAMIC LOADS. THE ANALYSIS AND BEHAVIOR OF THE COMPOSITE STRUCTURE AS WELL AS THE RCC STRUCTURE ARE EXAMINED. THE COMPOSITE STRUCTURE PROVED TO BE MORE ECONOMICAL AND RELIABLE THAN COMPARED TO A RCC STRUCTURE DESIGNED FOR SIMILAR AND LOADING CONDITIONS.
Composite Construction Method for Engineering and ArchitectureMimi Alguidano
Composite construction uses two materials together to utilize each material's strengths. It examines problems with steel-concrete beams, including concrete placement order and deflection monitoring. New approaches include beam-column systems and air ducts in box girders. Other composites include timber-concrete slabs and steel-timber trusses.
Composite construction is beneficial because concrete resists compression well and steel resists tension well. Joining them results in an efficient, lightweight design with construction speed benefits. It allows for reduced floor depths and foundation sizes.
The benefits of composite construction include speed, performance, and value. Steel erection is fast and prefabricated decks provide stiffness when concrete cures. Concrete also protects
The Structural Behaviour of Concrete Filled Steel Tubular columnsIRJET Journal
This document describes a study comparing the structural behavior of concrete-filled steel tubular columns made with different steel materials through numerical analysis and experimental testing. Six column specimens were tested - two each made with stainless steel, mild steel, and cold-formed steel tubes. Both short and long columns were analyzed. The numerical analysis found that stainless steel columns had the highest load-carrying capacity. The experimental results supported this, with stainless steel columns outperforming the other materials. There was good agreement between the numerical and experimental load values, with errors generally below 5%. The study concluded that stainless steel provided the best performance for concrete-filled steel tubular columns subjected to axial loads.
Prestressed concrete is concrete in which internal stresses are introduced to counteract external loads. Tendons are stretched elements that impart prestress, and anchorage devices enable the tendons to impart and maintain prestress. There are two main methods - pretensioning, where tendons are tensioned before concrete is cast, and post-tensioning, where tendons are tensioned against hardened concrete. Prestressed concrete uses high-strength materials like cement, concrete, and steel tendons or strands to achieve its compressive strength and durability advantages over reinforced concrete.
This document discusses steel-concrete composite construction. It describes shear connectors, which provide composite action between steel beams and concrete slabs. There are three main types of shear connectors: rigid connectors made of steel bars or angles that resist shear through bearing pressure; flexible stud connectors that bend and fail through yielding; and bond-type connectors that rely on bond and anchoring. The document discusses the design of shear connectors according to Indian codes IRC 22-1986 and IS 11384-1985, providing methods to calculate the design strength of shear connectors.
1) Prestressing of concrete involves applying permanent compressive stresses to the member before external loads using high-strength steel wires or strands. This reduces or eliminates tensile stresses from the loads.
2) Prestressing is applied by pulling wires or strands with hydraulic jacks and anchoring them. When the steel tries to regain its length, it exerts compressive forces on the concrete, creating a negative bending moment in the beam.
3) Higher strength concrete is typically used for prestressed members as it reduces losses of prestressing force from elastic shortening, creep, and shrinkage, improving efficiency. It also allows for faster construction.
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.
1) Bond refers to the interaction between reinforcing steel and concrete that allows transfer of stress between the two materials. It ensures strain compatibility for composite action.
2) Bond is achieved through chemical adhesion, friction due to surface roughness, and mechanical interlock from ribs on deformed bars.
3) There are two types of bond - local or flexural bond stress which resists slip, and anchorage or development length bond which develops stress transfer near bar ends. Anchorage is typically provided using bends and hooks.
This document compares reinforced cement concrete (RCC) and steel structures. RCC has better compressive and tensile strength than other building materials and can be molded into shapes. It is more durable and has a long life and low maintenance costs. Steel has high tensile strength and load-carrying capacity, but is more costly. It has better quality control than RCC. While RCC has higher fire resistance, steel structures are easier to repair and maintain. The document concludes that using steel and concrete composites combines their strengths for an effective and economic construction system.
Pre-stressed concrete is a combination of steel and concrete that takes advantage of each material's strengths. There are three main types of pre-stressed concrete: pre-tensioned concrete, bonded post-tensioned concrete, and unbonded post-tensioned concrete. Pre-tensioned concrete involves stressing steel reinforcement prior to placing concrete around it, while bonded and unbonded post-tensioned concrete involve stressing steel embedded in cured concrete. Pre-stressing concrete provides benefits like increased strength, reduced cracking and corrosion, and allowing for thinner members. The pre-stressing process requires careful planning and consideration of factors like creep, shrinkage, and stress losses over time.
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.
The document provides information on methods of prestressing 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.
Prestressed concrete uses high-strength steel tendons to place concrete in compression before loading. This counters the tensile stresses from loads and allows for longer spans and lighter structures. There are two main methods: pretensioning, where tendons are tensioned before concrete is poured, and post-tensioning, where tendons are tensioned after concrete cures. Prestressed concrete has advantages like reduced cracking, increased load capacity, and smaller deflections under loads.
This document provides an introduction and literature review on concrete filled steel tube (CFST) columns. Some key points:
1) CFST columns utilize the advantages of both steel and concrete by using a steel hollow section filled with concrete. They are widely used in building construction.
2) Previous research has shown CFST columns have improved structural performance due to confinement of the concrete core by the steel tube. They also have construction advantages due to their simple erection sequence.
3) The literature review covers the behavior of CFST under different load cases like axial, bending, and combined loads. It also discusses design concepts, analytical methods, and codes/standards for CFST columns.
prestressed concrete and precast concrete technology.pptxPRASANNABHAVANGR1
This document provides information on precast, prestressed concrete construction. It discusses how precast concrete elements are cast off-site in a controlled environment and transported to the construction site. This allows for faster, more efficient construction compared to site-cast concrete. Common precast structural elements include slabs, beams, columns, and wall panels. The document outlines the manufacturing process and how precast elements are joined together on-site. It also discusses some applications of precast concrete such as buildings, bridges, and water tanks.
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 defines and compares different types of prestressed concrete, including pre-tensioned and post-tensioned concrete. Pre-tensioned concrete involves stressing steel reinforcement prior to placing concrete around it. Post-tensioned concrete uses unstressed steel placed in concrete that is later tensioned. Bonded post-tensioning bonds the steel to the concrete, while unbonded systems separate the steel and concrete. Prestressed concrete provides benefits like increased strength, reduced cracking, and improved durability over conventional reinforced concrete.
comparison between Post tensioned slab and conventional slab03065661166
This document compares post-tensioned slabs and conventional reinforced concrete slabs. Post-tensioned slabs have tendons tensioned after the concrete sets, allowing for thinner slabs that deflect and crack less than reinforced concrete slabs under load. However, post-tensioned slabs require more skilled labor and specialized equipment during construction. Reinforced concrete slabs are simpler to build but thicker and have higher dead loads than equivalent post-tensioned slabs. The document concludes that post-tensioned slabs are generally more economical for large, heavy construction while reinforced concrete slabs are suitable for smaller projects.
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.
Reinforced concrete is concrete that is strengthened with rebar or steel reinforcement. It is stronger than plain concrete due to its ability to withstand both compressive and tensile stresses. The steel reinforcement provides tensile strength, while the concrete primarily resists compressive forces and protects the rebar from corrosion. Proper placement of the rebar within the formwork prior to pouring concrete is important to achieve the structural strength of the reinforced concrete. Testing of the concrete is also done to ensure it meets the required strength standards. Reinforced concrete has many advantages over plain concrete, including higher strength, durability, resistance to fire and weathering, and lower lifetime maintenance costs.
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.
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.
The document provides an introduction to reinforced cement concrete (RCC). It discusses that steel is strong in both tension and compression, whereas concrete is strong only in compression. Steel reinforcement is used to increase the tensile strength of concrete. The combination of steel and concrete results in RCC, which has a weight of 25,000 N/cum. Steel is the most suitable reinforcing material due to its high tensile strength, elasticity, bond with concrete, and availability in India. Mild steel bars have plain surfaces while high yield strength deformed (HYSD) bars have deformations that increase bond strength. Design of RCC involves consideration of loads such as dead, live, wind, snow, and seismic loads.
The document discusses stress ribbon bridges. It begins by explaining that a stress ribbon bridge is a tension structure similar to a suspension bridge, with suspension cables embedded in the deck which follows a catenary arc. Unlike simple suspension bridges, the ribbon is stressed in compression which adds stiffness. Supports provide upward thrusting arcs to change the grade between spans. Stress ribbon bridges are typically reinforced concrete with steel tensioning cables to prevent excessive flexing from vehicle traffic. Fewer than 50 have been built worldwide due to their rare design.
Experimental study on strength and flexural behaviour of reinforced concrete ...IOSR Journals
Abstract: Strength and flexural behaviour of reinforced concrete beams using deflected structural steel
reinforcement and the conventional steel reinforcement are conducted in this study. The reinforcement quantity
of both categories was approximately equalised. Mild steel flats with minimum thickness and corresponding
width are deflected to possible extent in a parabolic shape and semi-circular shape are fabricated and used as
deflected structural steel reinforcement in one part, whereas the fabrication of ribbed tar steel circular bars as
conventional reinforcement on the another part of the experiment for comparison in the concrete beams. All the
beams had same dimensions and same proportions of designed mix concrete, were tested under two point
loading system. As the result of experiments, it is found that the inverted catenary flats and their ties, transfers
the load through arch action of steel from loading points towards the supports before reaching the bottom
fibre at the centre of the beam as intended earlier. Thereby the load carrying capacity and the ductility ratio
has being increased in deflected structural steel reinforced beams when compared with ribbed tar steel
reinforced concrete beams, it is also observed that the failure mode (collapse pattern)is safer.
Keywords --Arch profile, Conventional steel reinforcement, Cracks, Collapse, Deflected structural steel,
Ductility ratio.
1) Prestressing of concrete involves applying permanent compressive stresses to the member before external loads using high-strength steel wires or strands. This reduces or eliminates tensile stresses from the loads.
2) Prestressing is applied by pulling wires or strands with hydraulic jacks and anchoring them. When the steel tries to regain its length, it exerts compressive forces on the concrete, creating a negative bending moment in the beam.
3) Higher strength concrete is typically used for prestressed members as it reduces losses of prestressing force from elastic shortening, creep, and shrinkage, improving efficiency. It also allows for faster construction.
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.
1) Bond refers to the interaction between reinforcing steel and concrete that allows transfer of stress between the two materials. It ensures strain compatibility for composite action.
2) Bond is achieved through chemical adhesion, friction due to surface roughness, and mechanical interlock from ribs on deformed bars.
3) There are two types of bond - local or flexural bond stress which resists slip, and anchorage or development length bond which develops stress transfer near bar ends. Anchorage is typically provided using bends and hooks.
This document compares reinforced cement concrete (RCC) and steel structures. RCC has better compressive and tensile strength than other building materials and can be molded into shapes. It is more durable and has a long life and low maintenance costs. Steel has high tensile strength and load-carrying capacity, but is more costly. It has better quality control than RCC. While RCC has higher fire resistance, steel structures are easier to repair and maintain. The document concludes that using steel and concrete composites combines their strengths for an effective and economic construction system.
Pre-stressed concrete is a combination of steel and concrete that takes advantage of each material's strengths. There are three main types of pre-stressed concrete: pre-tensioned concrete, bonded post-tensioned concrete, and unbonded post-tensioned concrete. Pre-tensioned concrete involves stressing steel reinforcement prior to placing concrete around it, while bonded and unbonded post-tensioned concrete involve stressing steel embedded in cured concrete. Pre-stressing concrete provides benefits like increased strength, reduced cracking and corrosion, and allowing for thinner members. The pre-stressing process requires careful planning and consideration of factors like creep, shrinkage, and stress losses over time.
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.
The document provides information on methods of prestressing 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.
Prestressed concrete uses high-strength steel tendons to place concrete in compression before loading. This counters the tensile stresses from loads and allows for longer spans and lighter structures. There are two main methods: pretensioning, where tendons are tensioned before concrete is poured, and post-tensioning, where tendons are tensioned after concrete cures. Prestressed concrete has advantages like reduced cracking, increased load capacity, and smaller deflections under loads.
This document provides an introduction and literature review on concrete filled steel tube (CFST) columns. Some key points:
1) CFST columns utilize the advantages of both steel and concrete by using a steel hollow section filled with concrete. They are widely used in building construction.
2) Previous research has shown CFST columns have improved structural performance due to confinement of the concrete core by the steel tube. They also have construction advantages due to their simple erection sequence.
3) The literature review covers the behavior of CFST under different load cases like axial, bending, and combined loads. It also discusses design concepts, analytical methods, and codes/standards for CFST columns.
prestressed concrete and precast concrete technology.pptxPRASANNABHAVANGR1
This document provides information on precast, prestressed concrete construction. It discusses how precast concrete elements are cast off-site in a controlled environment and transported to the construction site. This allows for faster, more efficient construction compared to site-cast concrete. Common precast structural elements include slabs, beams, columns, and wall panels. The document outlines the manufacturing process and how precast elements are joined together on-site. It also discusses some applications of precast concrete such as buildings, bridges, and water tanks.
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 defines and compares different types of prestressed concrete, including pre-tensioned and post-tensioned concrete. Pre-tensioned concrete involves stressing steel reinforcement prior to placing concrete around it. Post-tensioned concrete uses unstressed steel placed in concrete that is later tensioned. Bonded post-tensioning bonds the steel to the concrete, while unbonded systems separate the steel and concrete. Prestressed concrete provides benefits like increased strength, reduced cracking, and improved durability over conventional reinforced concrete.
comparison between Post tensioned slab and conventional slab03065661166
This document compares post-tensioned slabs and conventional reinforced concrete slabs. Post-tensioned slabs have tendons tensioned after the concrete sets, allowing for thinner slabs that deflect and crack less than reinforced concrete slabs under load. However, post-tensioned slabs require more skilled labor and specialized equipment during construction. Reinforced concrete slabs are simpler to build but thicker and have higher dead loads than equivalent post-tensioned slabs. The document concludes that post-tensioned slabs are generally more economical for large, heavy construction while reinforced concrete slabs are suitable for smaller projects.
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.
Reinforced concrete is concrete that is strengthened with rebar or steel reinforcement. It is stronger than plain concrete due to its ability to withstand both compressive and tensile stresses. The steel reinforcement provides tensile strength, while the concrete primarily resists compressive forces and protects the rebar from corrosion. Proper placement of the rebar within the formwork prior to pouring concrete is important to achieve the structural strength of the reinforced concrete. Testing of the concrete is also done to ensure it meets the required strength standards. Reinforced concrete has many advantages over plain concrete, including higher strength, durability, resistance to fire and weathering, and lower lifetime maintenance costs.
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.
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.
The document provides an introduction to reinforced cement concrete (RCC). It discusses that steel is strong in both tension and compression, whereas concrete is strong only in compression. Steel reinforcement is used to increase the tensile strength of concrete. The combination of steel and concrete results in RCC, which has a weight of 25,000 N/cum. Steel is the most suitable reinforcing material due to its high tensile strength, elasticity, bond with concrete, and availability in India. Mild steel bars have plain surfaces while high yield strength deformed (HYSD) bars have deformations that increase bond strength. Design of RCC involves consideration of loads such as dead, live, wind, snow, and seismic loads.
The document discusses stress ribbon bridges. It begins by explaining that a stress ribbon bridge is a tension structure similar to a suspension bridge, with suspension cables embedded in the deck which follows a catenary arc. Unlike simple suspension bridges, the ribbon is stressed in compression which adds stiffness. Supports provide upward thrusting arcs to change the grade between spans. Stress ribbon bridges are typically reinforced concrete with steel tensioning cables to prevent excessive flexing from vehicle traffic. Fewer than 50 have been built worldwide due to their rare design.
Experimental study on strength and flexural behaviour of reinforced concrete ...IOSR Journals
Abstract: Strength and flexural behaviour of reinforced concrete beams using deflected structural steel
reinforcement and the conventional steel reinforcement are conducted in this study. The reinforcement quantity
of both categories was approximately equalised. Mild steel flats with minimum thickness and corresponding
width are deflected to possible extent in a parabolic shape and semi-circular shape are fabricated and used as
deflected structural steel reinforcement in one part, whereas the fabrication of ribbed tar steel circular bars as
conventional reinforcement on the another part of the experiment for comparison in the concrete beams. All the
beams had same dimensions and same proportions of designed mix concrete, were tested under two point
loading system. As the result of experiments, it is found that the inverted catenary flats and their ties, transfers
the load through arch action of steel from loading points towards the supports before reaching the bottom
fibre at the centre of the beam as intended earlier. Thereby the load carrying capacity and the ductility ratio
has being increased in deflected structural steel reinforced beams when compared with ribbed tar steel
reinforced concrete beams, it is also observed that the failure mode (collapse pattern)is safer.
Keywords --Arch profile, Conventional steel reinforcement, Cracks, Collapse, Deflected structural steel,
Ductility ratio.
Similar to Introduction and methods of Prestressed Concrete (20)
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.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
13. What is Pre-Stressed
Concrete ?
• Prestressed concrete is basically concrete in which
internal stresses of a suitable magnitude and distribution
are introduced so that the stresses resulting from
external loads are counteracted to a desired degree.
• In reinforced concrete members, the prestress is
commonly introduced by tensioning the steel
reinforcement.
22. • Steel Wires – wire is a single unit made of steel.
• Strands – Group of wire not more than 7 wounded to
form a prestressing strand.
• Tendon – A number of strands or wires
are packaged together to form a prestressing tendon.
• Cable – When a number of tendons are
grouped together and form a single wire then it is called a
Cable.
Based upon the concrete-steel interface it can be classified
into two-part:
• Unbounded tendon – This tendon is one that is not
bonded or in which no concrete grouting is done
after prestressing.
• Bonded tendon – This tendon
is bounded by injecting concrete grout.
Tendons In Prestressed
Concrete
23.
24.
25.
26. Prestressed Concrete
(PSC)
Reinforced Cement Concrete
(RCC)
In PSC members steel plays active
role. The stress in steel prevails
whether external load is there or not.
In R.C.C members steel plays a
passive role. The stress in steel in
R.C.C members depends upon the
external loads. i.e., no external load,
no stress in steel.
In PSC, the stresses in steel is almost
constant
In R.C.C the stress in steel is variable
with the lever arm.
It has more shear resistance It has less shear resistance
In PSC members, deflections are less
because the eccentric prestressing
force will induce couple which will
cause upward deflections.
In R.C.C., deflections are more.
In PSC fatigue resistance is more
compare to R.C.C. because in PSC
stress in steel is load independent
In RCC fatigue resistance is less
compare to PSC because in RCC
stress in steel is load dependent
27. Prestressed Concrete
(PSC)
Reinforced Cement Concrete
(RCC)
PSC is more durable as high grade of
concrete is used which are more
dense in nature.
R.C.C. is less durable.
In PSC dimensions are less because
external stresses are counterbalance
by the internal stress induced by
prestress.
In RCC dimensions are large
compared to PSC
Reactions on column & footing are
less as a whole the quantity of
concrete is reduced by 30% and steel
reduced by about 60% to 70%.
R.C.C. is uneconomical for long span
because in R.C.C. dimension of
sections are large requiring more
concrete & steel. Moreover as self-
weight increases more reactions
acted on columns & footings, which
requires higher sizes.
28.
29.
30.
31.
32.
33.
34. Pretensioning Post tensioning
Prestressing is done before pouring
of concrete.
Prestressing is done after concrete
attains sufficient strength.
Pretensioning is developed due to
bonding between steel and concrete.
Post tensioning is developed due to
bearing.
Preferred for small structural
element and easy to transport.
Preferred for large structural
element and difficult to transport.
Similar structural members are
casted.
Members are casted according to
market requirements.
Casted in moulds.
Cables are used in place of wires and
jacks for stretching.
Greater certainty about the
prestressing force.
More economical to use a few cables
or bars with large forces in than
many small ones.
Suitable for bulk production.
Suited for medium to long-span in
situ work where the tensioning cost
is only a small proportion of the cost
of the whole job .
36. Advantages of PSC
Increase in durability.
Less deformations (improved serviceability).
Increase in shear capacity.
Lower construction cost.
Thinner slabs, which are especially important in high
rise buildings where floor thickness savings can
translate into additional floors for the same or lower
cost.
More aesthetic appeal due to slender sections.
More economical sections ( Mass production – it is
economical).
Long span structures are possible.
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