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 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.
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.
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.
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.
Pre stressed & pre-cast concrete technology - ce462Saqib Imran
1) Precast concrete consists of concrete elements that are cast and cured off-site and then transported for assembly. Prestressed concrete uses high-strength steel strands or bars that are tensioned to put the concrete in compression and improve its strength.
2) Common precasting techniques include pre-tensioning, where steel is tensioned before the concrete is poured, and post-tensioning, where steel is tensioned after the concrete cures.
3) Advantages of prestressed concrete include reduced cracking, lighter weight, and improved durability; disadvantages include higher material costs and need for specialized equipment.
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.
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.
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.
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.
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.
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.
Pre stressed & pre-cast concrete technology - ce462Saqib Imran
1) Precast concrete consists of concrete elements that are cast and cured off-site and then transported for assembly. Prestressed concrete uses high-strength steel strands or bars that are tensioned to put the concrete in compression and improve its strength.
2) Common precasting techniques include pre-tensioning, where steel is tensioned before the concrete is poured, and post-tensioning, where steel is tensioned after the concrete cures.
3) Advantages of prestressed concrete include reduced cracking, lighter weight, and improved durability; disadvantages include higher material costs and need for specialized equipment.
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.
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.
Behaviour of Steel Fibre Reinforced Concrete Beam under Cyclic LoadingIOSR Journals
Abstract: This paper describes the influence of steel fibre distribution on the ultimate strength of concrete
beams. An experimental & analytical investigation of the behaviour of concrete beams reinforced with
conventional steel bars and steel fibres under cyclic loading is presented. It is now well established that one of
the important properties of steel fibre reinforced concrete (SFRC) is its superior resistance to cracking and
crack propagation. As a result of this ability to arrest cracks, fibre composites possess increased extensibility
and tensile strength, both at first crack and at ultimate load and the fibres are able to hold the matrix together
even after extensive cracking. The net result of all these is to impart to the fibre composite pronounced post –
cracking ductility which is unheard of in ordinary concrete. The transformation from a brittle to a ductile type
of material would increase substantially the energy absorption characteristics of the fibre composite and its
ability to withstand repeatedly applied, shock or impact loading. Tests on conventionally reinforced concrete
beam specimens, containing steel fibres in different proportions, have been conducted to establish loaddeflection
curves. It was observed that SFRC beams showed enhanced properties compared to that of RC beams
with steel fibres. The experimental investigations are validated with the analytical studies carried out by finite
element models using ANSYS.
Keywords: Steel fiber, concrete, properties, crack, ductility, technology.
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.
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 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 provides information on prestressed concrete and the Freyssinet prestressing system. It discusses the principles of prestressing, including pre-tensioning and post-tensioning methods. It also describes the key components of the Freyssinet post-tensioning system, including prestressing steels, anchorages, ducts, supports, and couplers. The anchorages can be mono-strand or multi-strand and are designed to transfer prestressing forces to the concrete structure.
The Study of Flexural and Ultimate Behavior of Ferrocement Lightweight Beam b...IRJET Journal
1. The study examines the flexural and ultimate behavior of ferrocement lightweight beams using autoclaved aerated concrete (AAC) blocks.
2. Six beams were tested - three reinforced concrete beams and three ferrocement beams. Testing involved applying a single point load until failure and recording the first crack load, ultimate load, and deflections.
3. Test results found that ferrocement beams gave early warning of failure through initial cracking compared to sudden failure in reinforced concrete beams. Ferrocement beams also experienced greater deflections than reinforced concrete beams under the same loads.
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.
Stiffening and Strengthening of Deteriorated Cellular Beams by Local Post- Te...IRJET Journal
This document discusses research on strengthening deteriorated cellular beams through local post-tensioning. Cellular beams are prone to deterioration over time due to their increased depth and exposure. The study aims to introduce local post-tensioning as a simple, low-cost method to stiffen and strengthen cellular beams without adding new material. Local post-tensioning involves attaching reinforcing bars to the bottom of the beam and tensioning them using jacks to improve load capacity. Deteriorated beams were modeled and analyzed in ANSYS. The results showed that local post-tensioning combined with stiffeners was the most effective approach, able to recover over 180% of the original load capacity.
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.
Prestressing is a technique where tension is applied to concrete before hardening to improve its performance. There are two main types - pre-tensioning and post-tensioning. Pre-tensioning involves tensioning steel tendons before casting concrete, while post-tensioning tensions tendons after casting. There are losses in prestress over time from factors like elastic shortening, shrinkage, creep, and steel relaxation. Proper materials and design are needed to account for these losses and ensure structures perform as intended.
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.
These presentations were created during the 2016–2021 B.Arch programme.
Please refer to the references column at the end of each presentation for the information within.
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.
SHEAR STRENGTHENING OF REINFORCED AND PRESTRESSED CONCRETE BEAM USING FRPIRJET Journal
1) The document discusses an experimental investigation on strengthening the shear capacity of reinforced concrete T-beams using basalt fiber reinforced polymer (BFRP) sheets.
2) A total of 22 concrete T-beams were tested with varying BFRP sheet configurations to determine their effects on the shear capacity of the beams. One beam served as a control while others were strengthened externally with BFRP sheets.
3) The results found that using BFRP sheets in a U-wrap configuration increased the shear capacity of beams by up to 12.66% compared to the control beam. However, some beams failed through debonding of the BFRP sheets. Anchoring the sheets was found to improve shear
Numerical Study on Retrofitting Of Beam Column Joint Strengthened With CFRPIRJET Journal
This document presents a numerical study on retrofitting an exterior beam-column joint with carbon fiber reinforced polymer (CFRP). A finite element model of an unstrengthened joint and a joint strengthened with CFRP wrapping is created in ANSYS. The models are subjected to cyclic loading and their stress distributions and deformations are analyzed and compared. The results show that strengthening the joint with CFRP increases its structural stiffness, strength, and energy dissipation capacity. The load-carrying capacity of the strengthened joint is 30% higher than the unstrengthened joint. CFRP wrapping is an effective rehabilitation technique for improving the seismic performance of damaged reinforced concrete beam-column joints.
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.
Torsional strengthening of under reinforced concrete beams using crimped stee...eSAT Publishing House
This document summarizes an experimental study on enhancing the torsional strength of under-reinforced concrete beams using steel fiber reinforcement. Beams were cast with varying volumes of crimped steel fibers (0-1% by volume) and tested under torsion. Results showed that steel fiber reinforcement led to significant increases in ultimate load capacity and torsional moment strength compared to normal reinforced concrete beams. Specifically, beams with 0.75% fiber volume exhibited the highest load capacity (47% increase) and torsional moment (2.689 kNm). The study demonstrates that steel fiber reinforcement is effective at strengthening concrete beams against torsional loads.
The document summarizes an experiment comparing pre-stressed/post-tensioned reinforcement to traditional steel reinforcement in concrete slabs. Two slabs were fabricated - a post-tensioned slab with 3/4" threaded rod and a rebar reinforced slab with #4 rebar. Material properties were tested, including concrete compressive strength from cylinders. The post-tensioned slab resisted 3.135 kips before cracking compared to 1.200 kips for the rebar slab. Post-tensioning doubled the load at cracking and increased ultimate strength by 1.2x. While post-tensioning increased cracking load and strength, it reduced ductility compared to the rebar slab. The results show post-tensioning can
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.
Behaviour of Steel Fibre Reinforced Concrete Beam under Cyclic LoadingIOSR Journals
Abstract: This paper describes the influence of steel fibre distribution on the ultimate strength of concrete
beams. An experimental & analytical investigation of the behaviour of concrete beams reinforced with
conventional steel bars and steel fibres under cyclic loading is presented. It is now well established that one of
the important properties of steel fibre reinforced concrete (SFRC) is its superior resistance to cracking and
crack propagation. As a result of this ability to arrest cracks, fibre composites possess increased extensibility
and tensile strength, both at first crack and at ultimate load and the fibres are able to hold the matrix together
even after extensive cracking. The net result of all these is to impart to the fibre composite pronounced post –
cracking ductility which is unheard of in ordinary concrete. The transformation from a brittle to a ductile type
of material would increase substantially the energy absorption characteristics of the fibre composite and its
ability to withstand repeatedly applied, shock or impact loading. Tests on conventionally reinforced concrete
beam specimens, containing steel fibres in different proportions, have been conducted to establish loaddeflection
curves. It was observed that SFRC beams showed enhanced properties compared to that of RC beams
with steel fibres. The experimental investigations are validated with the analytical studies carried out by finite
element models using ANSYS.
Keywords: Steel fiber, concrete, properties, crack, ductility, technology.
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.
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 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 provides information on prestressed concrete and the Freyssinet prestressing system. It discusses the principles of prestressing, including pre-tensioning and post-tensioning methods. It also describes the key components of the Freyssinet post-tensioning system, including prestressing steels, anchorages, ducts, supports, and couplers. The anchorages can be mono-strand or multi-strand and are designed to transfer prestressing forces to the concrete structure.
The Study of Flexural and Ultimate Behavior of Ferrocement Lightweight Beam b...IRJET Journal
1. The study examines the flexural and ultimate behavior of ferrocement lightweight beams using autoclaved aerated concrete (AAC) blocks.
2. Six beams were tested - three reinforced concrete beams and three ferrocement beams. Testing involved applying a single point load until failure and recording the first crack load, ultimate load, and deflections.
3. Test results found that ferrocement beams gave early warning of failure through initial cracking compared to sudden failure in reinforced concrete beams. Ferrocement beams also experienced greater deflections than reinforced concrete beams under the same loads.
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.
Stiffening and Strengthening of Deteriorated Cellular Beams by Local Post- Te...IRJET Journal
This document discusses research on strengthening deteriorated cellular beams through local post-tensioning. Cellular beams are prone to deterioration over time due to their increased depth and exposure. The study aims to introduce local post-tensioning as a simple, low-cost method to stiffen and strengthen cellular beams without adding new material. Local post-tensioning involves attaching reinforcing bars to the bottom of the beam and tensioning them using jacks to improve load capacity. Deteriorated beams were modeled and analyzed in ANSYS. The results showed that local post-tensioning combined with stiffeners was the most effective approach, able to recover over 180% of the original load capacity.
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.
Prestressing is a technique where tension is applied to concrete before hardening to improve its performance. There are two main types - pre-tensioning and post-tensioning. Pre-tensioning involves tensioning steel tendons before casting concrete, while post-tensioning tensions tendons after casting. There are losses in prestress over time from factors like elastic shortening, shrinkage, creep, and steel relaxation. Proper materials and design are needed to account for these losses and ensure structures perform as intended.
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.
These presentations were created during the 2016–2021 B.Arch programme.
Please refer to the references column at the end of each presentation for the information within.
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.
SHEAR STRENGTHENING OF REINFORCED AND PRESTRESSED CONCRETE BEAM USING FRPIRJET Journal
1) The document discusses an experimental investigation on strengthening the shear capacity of reinforced concrete T-beams using basalt fiber reinforced polymer (BFRP) sheets.
2) A total of 22 concrete T-beams were tested with varying BFRP sheet configurations to determine their effects on the shear capacity of the beams. One beam served as a control while others were strengthened externally with BFRP sheets.
3) The results found that using BFRP sheets in a U-wrap configuration increased the shear capacity of beams by up to 12.66% compared to the control beam. However, some beams failed through debonding of the BFRP sheets. Anchoring the sheets was found to improve shear
Numerical Study on Retrofitting Of Beam Column Joint Strengthened With CFRPIRJET Journal
This document presents a numerical study on retrofitting an exterior beam-column joint with carbon fiber reinforced polymer (CFRP). A finite element model of an unstrengthened joint and a joint strengthened with CFRP wrapping is created in ANSYS. The models are subjected to cyclic loading and their stress distributions and deformations are analyzed and compared. The results show that strengthening the joint with CFRP increases its structural stiffness, strength, and energy dissipation capacity. The load-carrying capacity of the strengthened joint is 30% higher than the unstrengthened joint. CFRP wrapping is an effective rehabilitation technique for improving the seismic performance of damaged reinforced concrete beam-column joints.
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.
Torsional strengthening of under reinforced concrete beams using crimped stee...eSAT Publishing House
This document summarizes an experimental study on enhancing the torsional strength of under-reinforced concrete beams using steel fiber reinforcement. Beams were cast with varying volumes of crimped steel fibers (0-1% by volume) and tested under torsion. Results showed that steel fiber reinforcement led to significant increases in ultimate load capacity and torsional moment strength compared to normal reinforced concrete beams. Specifically, beams with 0.75% fiber volume exhibited the highest load capacity (47% increase) and torsional moment (2.689 kNm). The study demonstrates that steel fiber reinforcement is effective at strengthening concrete beams against torsional loads.
The document summarizes an experiment comparing pre-stressed/post-tensioned reinforcement to traditional steel reinforcement in concrete slabs. Two slabs were fabricated - a post-tensioned slab with 3/4" threaded rod and a rebar reinforced slab with #4 rebar. Material properties were tested, including concrete compressive strength from cylinders. The post-tensioned slab resisted 3.135 kips before cracking compared to 1.200 kips for the rebar slab. Post-tensioning doubled the load at cracking and increased ultimate strength by 1.2x. While post-tensioning increased cracking load and strength, it reduced ductility compared to the rebar slab. The results show post-tensioning can
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.
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
entering the data of eachmatch, we can get all type of reports instantly, which will be
useful to call back history of each player. Also the team performance in each match can
be obtained. We can get a report on number of matches, wins and lost.
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfBalvir Singh
Sri Guru Hargobind Ji (19 June 1595 - 3 March 1644) is revered as the Sixth Nanak.
• On 25 May 1606 Guru Arjan nominated his son Sri Hargobind Ji as his successor. Shortly
afterwards, Guru Arjan was arrested, tortured and killed by order of the Mogul Emperor
Jahangir.
• Guru Hargobind's succession ceremony took place on 24 June 1606. He was barely
eleven years old when he became 6th Guru.
• As ordered by Guru Arjan Dev Ji, he put on two swords, one indicated his spiritual
authority (PIRI) and the other, his temporal authority (MIRI). He thus for the first time
initiated military tradition in the Sikh faith to resist religious persecution, protect
people’s freedom and independence to practice religion by choice. He transformed
Sikhs to be Saints and Soldier.
• He had a long tenure as Guru, lasting 37 years, 9 months and 3 days
An In-Depth Exploration of Natural Language Processing: Evolution, Applicatio...DharmaBanothu
Natural language processing (NLP) has
recently garnered significant interest for the
computational representation and analysis of human
language. Its applications span multiple domains such
as machine translation, email spam detection,
information extraction, summarization, healthcare,
and question answering. This paper first delineates
four phases by examining various levels of NLP and
components of Natural Language Generation,
followed by a review of the history and progression of
NLP. Subsequently, we delve into the current state of
the art by presenting diverse NLP applications,
contemporary trends, and challenges. Finally, we
discuss some available datasets, models, and
evaluation metrics in NLP.
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.
Online train ticket booking system project.pdfKamal Acharya
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2. ● Introduction of prestressing
● Material and Hardware of prestressing
● Types of prestressing
● Equipment's used in prestressing types.
● Applications of prestressing
● Advantages of prestressing
● Disadvantages of prestressing
● conclusion
CONTENTS :-
3. Definition:
Pre-stressing is the application of an initial load on the structure so as to enable
the structure to counteract the stresses arising during its service period
Introduction of prestressing:
4. History:
The application of pre-stressing in concrete structures is not the only instance.
There were some earlier attempts made.Two of the instances are provided below
1) Force-fitting of metal bands on wooden barrels:
The metal bands around the barrel induce a state of initial hoop compression to
counteract the hoop tension caused by filling of liquid in the barrels.
Fieg1:wooden barrels wounded with steel bands
5. 2) Pre-tensioning of spokes in a bicycle wheel
The pre-tension is applied in the spoke to such an extent that there will
always be a residual tension in the spoke
Fig: spokes of a bicycle wheel in pretension
● The concept of prestressed concrete is also not new. In 1886, a patent was
granted for tightening steel tie rods in concrete blocks. This is analogous to
modern day segmental constructions.
● Early attempts were not very successful due to low strength of steel at
that time.Since we cannot prestress at high stress level, the prestress losses
due to creep and shrinkage of concrete quickly reduce the effectiveness
of prestressing.
6. The terms commonly used in prestressed concrete are explained. The terms are
placed in groups as per usage.
Forms of Prestressing Steel
Wires
Prestressing wire is a single unit made of steel.
Strands
Two, three or seven wires are wound to form
a prestressing strand.
Materials and Hardwares for prestressing:
7. Tendon
A group of strands or wires are wound to
form a prestressing tendon.
Cable
A group of tendons form a prestressing cable.
Bars
A tendon can be made up of a single steel bar. The diameter of a bar is much
larger than that of a wire.
8. Prestressing tendons:
Prestressing tendon may be in the form of stands , wires , round bar , or
threaded rods
Prestressing steel
Materials
High strength steel
Fiber-reinforced composite ( glass or carbon fibers )
:
13. Pretensioning v.s. posttensioning
In pretension , the tendons are tensioned against
some abutments before the concrete is placed.
After the concrete hardened , the tension force is
realeased.
The tendon tries to shrink back to the intial length but
the concrete resist it through the bond between them
, thus compression force is induced in concrete.
14.
15. Linear v.s. circular prestressing
Linear prestressing :Prestressing can be done in
straight structure such as beams
Circular prestressing : prestressing around a
circular structure , such as tank .
External vs. internal
Prestressing may be done inside or outside.
16. Bonded vs. unbonded tendon.
The tendon may be bonded to concrete
(prettensioning or posttensioning with
grouting)
Bonding prevent corosion of the tendon
The tendon may be unbounded to concrete
(posttensioning without grouting).
17. Bonded vs. unbonded
Unbonding allows readjustment of prestressing force at later times.
End-anchored vs. non-end-anchored
non-end –anchored :In pretensioning , tendons transfer the bond action
along the tendon .
End-anchored: in posttensioning , tendons are anchored at their ends
using mechanical devices to transfer the prestress to concrete.
Partial vs. full prestressing
Prestressing tendon may be used in combination with regular reinforcing
steel.
thus , it is something between full prestressed concrete (PC) and
reinforced concrete (RC).
The goal is to allow some tension and cracking under full service load
while ensuring sufficient ultimate strength.
We use partial prestressed concrete (PPC) to control camber and
deflection , increase ductility and save costs.
18.
19. Prestressing strand
Modulus of Elasticity
197000 Mpa for strand
207000 Mpa for bar
The modulus of elasticity of strand is lower than that of steel bar because
because strand is made from twisting of small wires together.
Hardwares & prestressing equipments
pretensioned members
Hold-down devices
Posttensioned members
anchorages
i. stressing anchorage
ii. Dead-end ancorage
Ducts
Posttensioning procedures
20. Bridges
Slabs in buildings
Water Tank
Concrete Pile
Thin Shell Structures
Offshore Platform
Nuclear Power Plant
Repair and Rehabilitations
Applications of prestressed concrete:
21. Advanages of Prestressing:
•Prestressed concrete is the main material for floors in
high-rise buildings because the floor thickness
savings can translate into additional floors for the same
(or lower) cost.
22. •Reduction of steel corrosion.
• Increase in durability.
•Full section is utilized.
•Higher moment of inertia (higher stiffness)
•Less deformations (improved serviceability).
•Increase in shear capacity
•Rapid construction.
• Better quality control .
•Reduced maintenance.
• Suitable for repetitive construction
23. Limitations of Prestressing
Although prestressing has advantages, some aspects need to be
carefully addressed.
• Prestressing needs skilled technology. Hence, it is not as common as
reinforced concrete.
• The use of high strength materials is costly.
• There is additional cost in auxiliary equipments.
• There is need for quality control and inspection.
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