This case study describes the innovative use of post-tensioned concrete in the construction of the David Brower Center in Berkeley, California. The building uses a hybrid system of post-tensioned concrete walls and frames to provide improved seismic performance and self-centering behavior after earthquakes. This allows the building to avoid permanent damage and remain functional. The post-tensioning reduces the amount of conventional reinforcement needed, making the building more compact and efficient to construct while also lowering its carbon footprint through the use of slag cement. Non-linear simulations were used to verify the design of this unique structural system.
Seismic retrofitting modifies existing structures to increase their resistance to earthquakes. Common techniques include base isolators, which separate the structure from the ground using flexible bearings; supplementary dampers, which absorb and dissipate vibrational energy; tuned mass dampers, which reduce vibrations; and slosh tanks and active control systems, which also increase damping. The goal of retrofitting is to protect lives and ensure structural survivability, functionality, and integrity for historically significant buildings. Retrofitting techniques have evolved with new materials and provisions, helping structures withstand seismic impacts.
Seismic base isolation in strengthening an existing retrofitted masonry reinf...eSAT Journals
Ā
Abstract Seismic base isolation is a fast advancing technology in which the superstructure is isolated from the entire structure or from the substructure by means of rubber bearing isolators or frictional sliding isolators. The main aim of the base isolation technology is to isolate the structure from the harmful effects of the ground accelerations or earthquake excitations. In this paper, the procedure for the selection of the three ground motions is briefly explained and they are used in analyzing a masonry ā reinforced concrete office building for the Internal Revenue Service in the Huating County of the Pingliang City in China. The structure is first analyzed with the PKPM software to ascertain the structural internal forces are within reasonable limits but because this software cannot be used to advance analysis in the area of base isolation, Sap 2000 is used to remodel the structure, analyze, then apply the seismic base isolation. This office building has been strengthened to be fortified against ultimate bearing capacity failure as it is an existing structure. The lead rubber bearing isolators, LRB 400, LRB 500 and LRB 600 are used to isolate the building model and results from the structural response are compared, first amongst the time histories and then between the enveloped time histories and the response spectrum. The floor joint accelerations are observed to be reduced and the joint velocities as well, whereas the floor joint displacements are increased. The response spectrum alone is seen to not be an enough ground acceleration parameter in a seismic analysis and design of this model; as such it is recommended to include time history analysis. The maximum percentage decrease in acceleration and velocity can be seen occurring in the response spectrum, namely, 85.82% and 59.76%, respectively. The maximum percentage increase in the displacement is also evident in the response spectrum, 57.59%. In the time histories, the maximum is seen in Ec County Y-direction for the acceleration reduction at a value of 60.57%; Delta artif records a maximum velocity reduction of 28.42% in the Y-direction and finally, the Delta artif X-direction also records a maximum displacement increment, at a value of 26.36%.
The document discusses techniques for seismic retrofitting of reinforced concrete buildings. It introduces base isolation, mass dampers, jacketing beams and columns, and adding shear walls as common retrofitting techniques. For each technique, it provides details on how they work and their benefits. The goal of retrofitting is to strengthen existing structures to make them more resistant to seismic activity and protect human life.
Comparision of building for sesmic response by using base isolationeSAT Journals
Ā
Abstract
Throughout historic time Earthquakes are one of the natural hazards that occur due to sudden violent movement of earthās
surface which causes damage to property, especially to man-made structures . Base isolation is one of the most powerful tools of
earthquake engineering pertaining to the passive structural vibration control technologies. The application of the base isolation
techniques to protect structures against damage from earthquake attacks has been considered as one of the most effective
approaches and has gained increasing acceptance during the last two decades. This paper present three dimensional nonlinear
time history analysis is performed on r/c building by the use of computer program SAP 2000 v12.0.0. The dynamic analysis of the
structure has been carried out and the performance of the building with and without isolator is studied. The main objective here is
to make seismic response control by providing Isolators and comparing between the fixed based and isolated base building.
Rubber bearing and Friction pendulum bearing are used
Keywords: Base Isolation; Seismic Response; Time History
This document summarizes a dissertation on the effect of non-seismic walls on moment resisting frames in buildings. The dissertation examines whether reinforced concrete walls like stairwells and elevator shafts can be neglected in structural analysis. Through modeling and analysis of various building configurations using software, the dissertation found that for buildings up to 12 floors, such walls can be neglected and designed only for gravity loads if certain conditions are met regarding the walls' reinforcement and displacement. The presence of additional walls beyond one actually did not significantly increase the share of lateral loads resisted by the walls. The dissertation provides valuable insights into the interaction between structural wall and frame systems.
Comparison of Mesh Type Seismic Retrofitting for Masonry Structureschali090
Ā
The tremendous loss of life that resulted in the aftermath of recent earthquakes in developing countries is mostly due to the collapse of non-engineered building structures. It has been observed that these buildings cannot withstand the lateral loads imposed by an earthquake and often fails, in a brittle manner. This underscores the urgency to find simple and economic solutions to reinforce these buildings. Different conventional retrofitting techniques are available to increase the strength and/or ductility of unreinforced masonry walls. Recent years, several researches work on mesh type retrofitting for masonry structures to delay or prevent the collapse of buildings and reduce the number of lives lost during devastating earthquake events. This paper reviews and discusses the state-of-the-art on seismic retrofitting of masonry walls with emphasis on the mesh type retrofitting techniques include retrofitting procedures, cost, improvement in structural performance and limitations.
Seismic retrofitting modifies existing structures to increase their resistance to earthquakes. Common techniques include base isolators, which separate the structure from the ground using flexible bearings; supplementary dampers, which absorb and dissipate vibrational energy; tuned mass dampers, which reduce vibrations; and slosh tanks and active control systems, which also increase damping. The goal of retrofitting is to protect lives and ensure structural survivability, functionality, and integrity for historically significant buildings. Retrofitting techniques have evolved with new materials and provisions, helping structures withstand seismic impacts.
Seismic base isolation in strengthening an existing retrofitted masonry reinf...eSAT Journals
Ā
Abstract Seismic base isolation is a fast advancing technology in which the superstructure is isolated from the entire structure or from the substructure by means of rubber bearing isolators or frictional sliding isolators. The main aim of the base isolation technology is to isolate the structure from the harmful effects of the ground accelerations or earthquake excitations. In this paper, the procedure for the selection of the three ground motions is briefly explained and they are used in analyzing a masonry ā reinforced concrete office building for the Internal Revenue Service in the Huating County of the Pingliang City in China. The structure is first analyzed with the PKPM software to ascertain the structural internal forces are within reasonable limits but because this software cannot be used to advance analysis in the area of base isolation, Sap 2000 is used to remodel the structure, analyze, then apply the seismic base isolation. This office building has been strengthened to be fortified against ultimate bearing capacity failure as it is an existing structure. The lead rubber bearing isolators, LRB 400, LRB 500 and LRB 600 are used to isolate the building model and results from the structural response are compared, first amongst the time histories and then between the enveloped time histories and the response spectrum. The floor joint accelerations are observed to be reduced and the joint velocities as well, whereas the floor joint displacements are increased. The response spectrum alone is seen to not be an enough ground acceleration parameter in a seismic analysis and design of this model; as such it is recommended to include time history analysis. The maximum percentage decrease in acceleration and velocity can be seen occurring in the response spectrum, namely, 85.82% and 59.76%, respectively. The maximum percentage increase in the displacement is also evident in the response spectrum, 57.59%. In the time histories, the maximum is seen in Ec County Y-direction for the acceleration reduction at a value of 60.57%; Delta artif records a maximum velocity reduction of 28.42% in the Y-direction and finally, the Delta artif X-direction also records a maximum displacement increment, at a value of 26.36%.
The document discusses techniques for seismic retrofitting of reinforced concrete buildings. It introduces base isolation, mass dampers, jacketing beams and columns, and adding shear walls as common retrofitting techniques. For each technique, it provides details on how they work and their benefits. The goal of retrofitting is to strengthen existing structures to make them more resistant to seismic activity and protect human life.
Comparision of building for sesmic response by using base isolationeSAT Journals
Ā
Abstract
Throughout historic time Earthquakes are one of the natural hazards that occur due to sudden violent movement of earthās
surface which causes damage to property, especially to man-made structures . Base isolation is one of the most powerful tools of
earthquake engineering pertaining to the passive structural vibration control technologies. The application of the base isolation
techniques to protect structures against damage from earthquake attacks has been considered as one of the most effective
approaches and has gained increasing acceptance during the last two decades. This paper present three dimensional nonlinear
time history analysis is performed on r/c building by the use of computer program SAP 2000 v12.0.0. The dynamic analysis of the
structure has been carried out and the performance of the building with and without isolator is studied. The main objective here is
to make seismic response control by providing Isolators and comparing between the fixed based and isolated base building.
Rubber bearing and Friction pendulum bearing are used
Keywords: Base Isolation; Seismic Response; Time History
This document summarizes a dissertation on the effect of non-seismic walls on moment resisting frames in buildings. The dissertation examines whether reinforced concrete walls like stairwells and elevator shafts can be neglected in structural analysis. Through modeling and analysis of various building configurations using software, the dissertation found that for buildings up to 12 floors, such walls can be neglected and designed only for gravity loads if certain conditions are met regarding the walls' reinforcement and displacement. The presence of additional walls beyond one actually did not significantly increase the share of lateral loads resisted by the walls. The dissertation provides valuable insights into the interaction between structural wall and frame systems.
Comparison of Mesh Type Seismic Retrofitting for Masonry Structureschali090
Ā
The tremendous loss of life that resulted in the aftermath of recent earthquakes in developing countries is mostly due to the collapse of non-engineered building structures. It has been observed that these buildings cannot withstand the lateral loads imposed by an earthquake and often fails, in a brittle manner. This underscores the urgency to find simple and economic solutions to reinforce these buildings. Different conventional retrofitting techniques are available to increase the strength and/or ductility of unreinforced masonry walls. Recent years, several researches work on mesh type retrofitting for masonry structures to delay or prevent the collapse of buildings and reduce the number of lives lost during devastating earthquake events. This paper reviews and discusses the state-of-the-art on seismic retrofitting of masonry walls with emphasis on the mesh type retrofitting techniques include retrofitting procedures, cost, improvement in structural performance and limitations.
IRJET- Comparative Study of Multi-Storey Building with Coupled Shear Wall...IRJET Journal
Ā
This document presents a comparative study of multi-storey buildings with conventional shear walls and coupled shear walls. It describes modeling 10, 20, and 30-story buildings of each wall type and analyzing them using response spectrum analysis and equivalent static analysis. The results, including storey displacements, drifts, shears, overturning moments, and stiffnesses, are compared. The conclusions show that coupled shear walls perform better than conventional shear walls in resisting seismic forces in tall buildings.
Past earthquakes have shown that existing buildings designed to older seismic codes are vulnerable. Retrofitting techniques can upgrade seismic capacity. This paper evaluates four retrofitting techniques applied to four existing reinforced concrete building models: adding reinforced concrete walls, steel bracing, column jacketing, and strengthening columns with steel angles. Each technique is examined to determine its effect on top displacement, acceleration, base shear, and period. The technique with the minimum response for each model will be selected as the optimal retrofitting method for that structure. Several retrofitting techniques are described, including concrete jacketing, walls, and bracing. Factors such as strength, ductility, stiffness, bond, and material properties must be considered in retrofitting design.
Seismic analysis of multi storey reinforced concrete buildings frameāankialok
Ā
The opinion that designing new buildings to be Earthquake resistant will cause substantial additional costs is still among the constructional professionals. In a country of moderate seismicity adequate seismic resistance of new buildings may be achieved at no or no significant additional cost however the expenditure needed to ensure adequate seismic resistance may depend strongly on the approach selected during the conceptual design phase and the relevant design method. Regarding the conceptual design phase early collaboration between the architect and civil engineering is crucial.
The document discusses seismic retrofitting of buildings to make them more resistant to earthquakes. It describes how seismic retrofitting includes strengthening structural elements like connections, walls, and foundations. It outlines several methods for retrofitting such as adding new structural elements like walls, using innovative materials like fiber reinforced plastics, implementing base isolation systems, and supplemental energy dissipation. The document provides details on evaluating seismic vulnerability and the need for retrofitting to improve building safety, reduce hazards, and limit losses from earthquakes.
Eatrhquake response of reinforced cocrete multi storey building with base iso...eSAT Journals
Ā
This document summarizes a study on the earthquake response of base isolated reinforced concrete buildings. It describes the basic concept of base isolation, which aims to protect structures from seismic forces by isolating the building from ground movement using devices called isolators. It then discusses different types of isolators and presents the results of analyzing a 3D 8-story building model using different isolators, finding that base isolation substantially reduces base shear, displacements, and member forces compared to a fixed-base building.
It contains details of retrofitting techniques and their application in various aspects in historical monuments. It would help to protect several heritage structures from the devastating effect of the earthquake. Some applications are also helpful too counter act the severe effect of the wind load. There are many historical heritages especially in India, are reopened to the public after being retrofitted and renovated.
Earthquake Performance of RCC Frame Structure using different Types of Bracin...IRJET Journal
Ā
This document summarizes research on using different types of bracings (X, V, inverted V) and lead rubber bearing base isolation to improve the earthquake performance of reinforced concrete frame structures. The forces on structures using different bracing configurations are analyzed using computer software. Bracings increase structural stiffness and strength while reducing deformations from lateral loads like wind and earthquakes. Base isolation increases the fundamental period of the structure to reduce earthquake forces by separating the superstructure from the substructure with flexible isolators. Lead rubber bearings are discussed as an effective isolation system that provides horizontal flexibility, energy dissipation, and vertical rigidity.
This document discusses base isolation, which is a technique used to protect structures from earthquake forces. Base isolation involves installing bearing pads between a building and its foundation, allowing the structure to move independently from the ground during an earthquake. When ground shakes, the bearing pads allow the building to remain stationary while the foundation moves beneath it. This isolates the building from earthquake forces. The document then reviews different base isolation system designs and locations, comparing the performance of isolated versus fixed-base structures through various case studies and analyses. It concludes that base isolation is an effective method to significantly reduce seismic forces on buildings and bridges by distributing earthquake loads more evenly.
The document discusses base isolation, which aims to protect structures from earthquake damage by partially decoupling the structure from ground motion. It describes various types of base isolation systems, including elastomeric and sliding systems. Research is ongoing to develop natural base isolation using materials like soil and sand. Case studies demonstrate the successful application of base isolation in retrofitting historic structures and new construction. In conclusion, base isolation is a proven seismic protection method when isolation devices and planning are properly implemented.
Seismic vulnerability and building performance for structures and MEP Equipmentmichaeljmack
Ā
Here are some recommendations for specifying concrete, rebars, etc. to improve performance during an earthquake:
- Specify higher grade/strength concrete and reinforcing steel to resist seismic forces better.
- Provide continuous reinforcement with lap splices located away from regions of high stress.
- Use seismic/hoop reinforcement in potential plastic hinge regions like beam-column joints.
- Consider use of seismic hooks on longitudinal rebar at ends to improve ductility.
- Ensure minimum concrete cover over reinforcing is maintained as per code.
- For cast-in-place structures, consider post-installed reinforcement like rebar micropiles if needed to strengthen existing foundations.
- For precast structures,
Earthquake Resistant Building - Base Isolation TechniqueRajat Nainwal
Ā
It gives a complete idea of concept, design and construction detail of Base Isolation Technique which is used for making the buildings earthquake resistant to a much greater extent.
1) Traditional stone masonry buildings in India, constructed using thick walls of rounded stones with mud mortar, are very vulnerable to earthquakes due to deficiencies in wall construction, connections between walls, and connections to roofs.
2) During past earthquakes, these buildings commonly failed through bulging or separation of walls, separation of walls at corners, and collapse of poorly attached roofs.
3) To improve earthquake resistance, stone walls should be constructed in lifts with shaped stones and stronger mortar, include through-stones or overlapping bonds, and have horizontal reinforcing bands at floors, roofs, and gables to connect walls.
The document discusses reinforced hollow concrete block masonry (RHCBM) as a construction method that can effectively resist seismic forces. RHCBM involves reinforcing hollow concrete blocks with vertical and horizontal steel reinforcement. It provides benefits like increased strength, ductility, cost-effectiveness, and faster construction compared to other methods. For existing non-engineered masonry structures, retrofitting techniques like grouting and wire meshing can be used to enhance earthquake resistance. Experimental results show RHCBM panels have higher ultimate load capacity and displacement ductility than conventional masonry.
Report on Study on Base Isolation Techniques.Gaurav Mewara
Ā
Base Isolation technique is on of the advance technique used for construction of earthquake resisting sturcture.
All earthquake resisting structure are based on this technique.
This consit report on study of base isolation with its advantages disadvanges.
Seismic Base Isolators under Individual and Combined Use in Multi Storied Bui...IRJET Journal
Ā
This document reviews the use of seismic base isolators under individual and combined configurations in multi-story buildings. It discusses different types of base isolators including lead rubber bearings and friction pendulum bearings. It also reviews past literature that has evaluated the seismic response of buildings isolated with different isolator configurations and combinations. The literature shows that base isolation is effective at reducing floor accelerations, inter-story drifts, and base shear. Combined isolation systems that use multiple isolator types can further reduce responses compared to individual isolator systems, but may increase displacements.
This document discusses a study investigating the effectiveness of nonlinear fluid viscous dampers (NFVDs) in controlling the seismic response of base-isolated buildings. The study models 10-story steel moment frames isolated with lead rubber bearings and supplemented with NFVDs. NFVDs are placed in different configurations and with varying damping exponents. Nonlinear time history analyses are performed under ground motions. Results are evaluated in terms of displacements, drifts, accelerations, forces, energy, and hysteretic behavior. The main finding is that base-isolated buildings equipped with appropriately designed NFVDs can satisfactorily respond to seismic loads.
This document provides an overview of base isolation, which is a seismic protection system that mitigates earthquake damage by isolating structures from ground motions. It discusses the concepts of base isolation, including introducing flexibility to reduce transmitted forces. Common isolation components like elastomeric and lead-rubber bearings are described. The document also covers principles, suitability, differences between isolated and fixed structures, and real-world applications of base isolation in over 1000 buildings worldwide.
This document provides a summary of base isolation as a seismic retrofitting technique. It defines base isolation as decoupling a structure from its foundation to protect it during earthquakes. It describes different types of base isolators using materials like rubber, lead and steel. Advantages include reducing structural damage, secondary damage, and maintenance costs. Disadvantages include challenges implementing for tall buildings. Examples of base isolated structures worldwide and in India are given. The document concludes with suggestions for government initiatives to develop this technology in India.
The document discusses various techniques for seismic retrofitting of structures. It defines seismic retrofitting as modifying existing structures to make them more resistant to earthquakes and ground motion. Some common retrofitting techniques mentioned include adding new shear walls, steel bracing, and jacketing of columns. Innovative materials like fiber reinforced polymers are also discussed. Base isolation methods are described as well, which aim to isolate the structure from foundation movement. The document provides details on different retrofitting methods and their effectiveness through examples. It also discusses challenges in retrofitting and importance of codes and guidelines.
IRJET- Analysis of Various Effects on Multistory Building (G+27) by Staad Pro...IRJET Journal
Ā
This document analyzes the effects of shear walls on a 28-story building modelled in STAAD Pro software. Three models are considered: one without shear walls and two with shear walls in different locations (inward and outward parts of the building). The models are compared based on load transfer and lateral displacement of structural elements. Results show that providing shear walls in suitable locations significantly reduces displacements due to earthquake and wind loads. The document also reviews previous studies on shear wall behavior and modelling approaches. Methodology describes analyzing a 9-story building model with and without shear walls to determine optimal wall locations based on structural displacement and storey drifting.
IRJET- Comparative Study of Multi-Storey Building with Coupled Shear Wall...IRJET Journal
Ā
This document presents a comparative study of multi-storey buildings with conventional shear walls and coupled shear walls. It describes modeling 10, 20, and 30-story buildings of each wall type and analyzing them using response spectrum analysis and equivalent static analysis. The results, including storey displacements, drifts, shears, overturning moments, and stiffnesses, are compared. The conclusions show that coupled shear walls perform better than conventional shear walls in resisting seismic forces in tall buildings.
Past earthquakes have shown that existing buildings designed to older seismic codes are vulnerable. Retrofitting techniques can upgrade seismic capacity. This paper evaluates four retrofitting techniques applied to four existing reinforced concrete building models: adding reinforced concrete walls, steel bracing, column jacketing, and strengthening columns with steel angles. Each technique is examined to determine its effect on top displacement, acceleration, base shear, and period. The technique with the minimum response for each model will be selected as the optimal retrofitting method for that structure. Several retrofitting techniques are described, including concrete jacketing, walls, and bracing. Factors such as strength, ductility, stiffness, bond, and material properties must be considered in retrofitting design.
Seismic analysis of multi storey reinforced concrete buildings frameāankialok
Ā
The opinion that designing new buildings to be Earthquake resistant will cause substantial additional costs is still among the constructional professionals. In a country of moderate seismicity adequate seismic resistance of new buildings may be achieved at no or no significant additional cost however the expenditure needed to ensure adequate seismic resistance may depend strongly on the approach selected during the conceptual design phase and the relevant design method. Regarding the conceptual design phase early collaboration between the architect and civil engineering is crucial.
The document discusses seismic retrofitting of buildings to make them more resistant to earthquakes. It describes how seismic retrofitting includes strengthening structural elements like connections, walls, and foundations. It outlines several methods for retrofitting such as adding new structural elements like walls, using innovative materials like fiber reinforced plastics, implementing base isolation systems, and supplemental energy dissipation. The document provides details on evaluating seismic vulnerability and the need for retrofitting to improve building safety, reduce hazards, and limit losses from earthquakes.
Eatrhquake response of reinforced cocrete multi storey building with base iso...eSAT Journals
Ā
This document summarizes a study on the earthquake response of base isolated reinforced concrete buildings. It describes the basic concept of base isolation, which aims to protect structures from seismic forces by isolating the building from ground movement using devices called isolators. It then discusses different types of isolators and presents the results of analyzing a 3D 8-story building model using different isolators, finding that base isolation substantially reduces base shear, displacements, and member forces compared to a fixed-base building.
It contains details of retrofitting techniques and their application in various aspects in historical monuments. It would help to protect several heritage structures from the devastating effect of the earthquake. Some applications are also helpful too counter act the severe effect of the wind load. There are many historical heritages especially in India, are reopened to the public after being retrofitted and renovated.
Earthquake Performance of RCC Frame Structure using different Types of Bracin...IRJET Journal
Ā
This document summarizes research on using different types of bracings (X, V, inverted V) and lead rubber bearing base isolation to improve the earthquake performance of reinforced concrete frame structures. The forces on structures using different bracing configurations are analyzed using computer software. Bracings increase structural stiffness and strength while reducing deformations from lateral loads like wind and earthquakes. Base isolation increases the fundamental period of the structure to reduce earthquake forces by separating the superstructure from the substructure with flexible isolators. Lead rubber bearings are discussed as an effective isolation system that provides horizontal flexibility, energy dissipation, and vertical rigidity.
This document discusses base isolation, which is a technique used to protect structures from earthquake forces. Base isolation involves installing bearing pads between a building and its foundation, allowing the structure to move independently from the ground during an earthquake. When ground shakes, the bearing pads allow the building to remain stationary while the foundation moves beneath it. This isolates the building from earthquake forces. The document then reviews different base isolation system designs and locations, comparing the performance of isolated versus fixed-base structures through various case studies and analyses. It concludes that base isolation is an effective method to significantly reduce seismic forces on buildings and bridges by distributing earthquake loads more evenly.
The document discusses base isolation, which aims to protect structures from earthquake damage by partially decoupling the structure from ground motion. It describes various types of base isolation systems, including elastomeric and sliding systems. Research is ongoing to develop natural base isolation using materials like soil and sand. Case studies demonstrate the successful application of base isolation in retrofitting historic structures and new construction. In conclusion, base isolation is a proven seismic protection method when isolation devices and planning are properly implemented.
Seismic vulnerability and building performance for structures and MEP Equipmentmichaeljmack
Ā
Here are some recommendations for specifying concrete, rebars, etc. to improve performance during an earthquake:
- Specify higher grade/strength concrete and reinforcing steel to resist seismic forces better.
- Provide continuous reinforcement with lap splices located away from regions of high stress.
- Use seismic/hoop reinforcement in potential plastic hinge regions like beam-column joints.
- Consider use of seismic hooks on longitudinal rebar at ends to improve ductility.
- Ensure minimum concrete cover over reinforcing is maintained as per code.
- For cast-in-place structures, consider post-installed reinforcement like rebar micropiles if needed to strengthen existing foundations.
- For precast structures,
Earthquake Resistant Building - Base Isolation TechniqueRajat Nainwal
Ā
It gives a complete idea of concept, design and construction detail of Base Isolation Technique which is used for making the buildings earthquake resistant to a much greater extent.
1) Traditional stone masonry buildings in India, constructed using thick walls of rounded stones with mud mortar, are very vulnerable to earthquakes due to deficiencies in wall construction, connections between walls, and connections to roofs.
2) During past earthquakes, these buildings commonly failed through bulging or separation of walls, separation of walls at corners, and collapse of poorly attached roofs.
3) To improve earthquake resistance, stone walls should be constructed in lifts with shaped stones and stronger mortar, include through-stones or overlapping bonds, and have horizontal reinforcing bands at floors, roofs, and gables to connect walls.
The document discusses reinforced hollow concrete block masonry (RHCBM) as a construction method that can effectively resist seismic forces. RHCBM involves reinforcing hollow concrete blocks with vertical and horizontal steel reinforcement. It provides benefits like increased strength, ductility, cost-effectiveness, and faster construction compared to other methods. For existing non-engineered masonry structures, retrofitting techniques like grouting and wire meshing can be used to enhance earthquake resistance. Experimental results show RHCBM panels have higher ultimate load capacity and displacement ductility than conventional masonry.
Report on Study on Base Isolation Techniques.Gaurav Mewara
Ā
Base Isolation technique is on of the advance technique used for construction of earthquake resisting sturcture.
All earthquake resisting structure are based on this technique.
This consit report on study of base isolation with its advantages disadvanges.
Seismic Base Isolators under Individual and Combined Use in Multi Storied Bui...IRJET Journal
Ā
This document reviews the use of seismic base isolators under individual and combined configurations in multi-story buildings. It discusses different types of base isolators including lead rubber bearings and friction pendulum bearings. It also reviews past literature that has evaluated the seismic response of buildings isolated with different isolator configurations and combinations. The literature shows that base isolation is effective at reducing floor accelerations, inter-story drifts, and base shear. Combined isolation systems that use multiple isolator types can further reduce responses compared to individual isolator systems, but may increase displacements.
This document discusses a study investigating the effectiveness of nonlinear fluid viscous dampers (NFVDs) in controlling the seismic response of base-isolated buildings. The study models 10-story steel moment frames isolated with lead rubber bearings and supplemented with NFVDs. NFVDs are placed in different configurations and with varying damping exponents. Nonlinear time history analyses are performed under ground motions. Results are evaluated in terms of displacements, drifts, accelerations, forces, energy, and hysteretic behavior. The main finding is that base-isolated buildings equipped with appropriately designed NFVDs can satisfactorily respond to seismic loads.
This document provides an overview of base isolation, which is a seismic protection system that mitigates earthquake damage by isolating structures from ground motions. It discusses the concepts of base isolation, including introducing flexibility to reduce transmitted forces. Common isolation components like elastomeric and lead-rubber bearings are described. The document also covers principles, suitability, differences between isolated and fixed structures, and real-world applications of base isolation in over 1000 buildings worldwide.
This document provides a summary of base isolation as a seismic retrofitting technique. It defines base isolation as decoupling a structure from its foundation to protect it during earthquakes. It describes different types of base isolators using materials like rubber, lead and steel. Advantages include reducing structural damage, secondary damage, and maintenance costs. Disadvantages include challenges implementing for tall buildings. Examples of base isolated structures worldwide and in India are given. The document concludes with suggestions for government initiatives to develop this technology in India.
The document discusses various techniques for seismic retrofitting of structures. It defines seismic retrofitting as modifying existing structures to make them more resistant to earthquakes and ground motion. Some common retrofitting techniques mentioned include adding new shear walls, steel bracing, and jacketing of columns. Innovative materials like fiber reinforced polymers are also discussed. Base isolation methods are described as well, which aim to isolate the structure from foundation movement. The document provides details on different retrofitting methods and their effectiveness through examples. It also discusses challenges in retrofitting and importance of codes and guidelines.
IRJET- Analysis of Various Effects on Multistory Building (G+27) by Staad Pro...IRJET Journal
Ā
This document analyzes the effects of shear walls on a 28-story building modelled in STAAD Pro software. Three models are considered: one without shear walls and two with shear walls in different locations (inward and outward parts of the building). The models are compared based on load transfer and lateral displacement of structural elements. Results show that providing shear walls in suitable locations significantly reduces displacements due to earthquake and wind loads. The document also reviews previous studies on shear wall behavior and modelling approaches. Methodology describes analyzing a 9-story building model with and without shear walls to determine optimal wall locations based on structural displacement and storey drifting.
Evaluation of Seismic Behaviour of RCC Building using Coupled Shear wallIRJET Journal
Ā
1) The document analyzes the seismic behavior of reinforced concrete buildings with solid shear walls and coupled shear walls located in seismic zone IV.
2) Coupled shear walls consist of two or more shear walls connected by a coupling beam, which allows for openings. The performance depends on the arrangement and size of the coupling beam.
3) A 10-story reinforced concrete special moment resisting frame building with solid and coupled shear walls in the corners is modeled and analyzed using ETABS software. Responses such as story displacement, drift, and shear are evaluated and compared.
1. The document discusses parameters that affect the strength of concrete in externally prestressed bridges. It examines factors like tendon layout, prestressing method, effective depth and eccentricity of external tendons, and materials used for tendons.
2. Studies have found that draped tendon profiles provide higher strength than straight profiles. External prestressing requires more prestressing force than internal prestressing, except for very deep girders. Increased effective depth and eccentricity of external tendons enhances strength.
3. Carbon fiber reinforced polymer tendons are an alternative to steel but have issues with brittleness and cost. Overall, optimizing tendon layout and placement can improve the strength of externally prestressed concrete bridges
IRJET- Post Peak Response of Reinforced Concrete Frames with and without in F...IRJET Journal
Ā
This document discusses the effect of masonry infill panels, cross bracing, and viscous dampers on the seismic response of reinforced concrete frames. It analyzes a 7-story reinforced concrete building model with and without these elements using nonlinear static analysis. The addition of masonry infill walls, cross bracing, and viscous dampers reduces storey displacements and drift compared to the bare frame model. The equivalent strut method is used to model the infill walls, and cross bracing is modeled using diagonal steel braces. Viscous dampers absorb seismic energy to damp the motion of the building. Nonlinear static pushover analysis is performed using ETABS and SAP2000 software.
This document summarizes techniques for seismic retrofitting of existing structures. It defines seismic retrofitting as modifying structures to make them more resistant to earthquakes. Common retrofitting techniques discussed include adding new shear walls, steel bracing, jacketing columns and beams, using innovative materials like fiber reinforced polymers, base isolation using elastomeric bearings or sliding systems, and installing seismic dampers. The document also discusses retrofitting performance objectives, codes and guidelines, and provides examples of retrofitted structures.
IRJET - Study on Lateral Structural System on Different Height on Asymmet...IRJET Journal
Ā
This document presents a study on using different lateral load resisting structural systems (shear walls and bracing) in asymmetric buildings of varying heights located in a high seismic zone. Finite element models of bare frame, shear wall, and braced configurations were created and analyzed using software. Placement of shear walls and bracing at the core or corners resulted in lower displacements and drifts compared to bare frames. Taller buildings benefited more from these lateral systems. Shear walls and bracing effectively resist earthquake forces and improve building performance.
This document describes a study comparing the behavior of buildings with solid shear walls and coupled shear walls. Coupled shear walls are made of wall piers connected by coupling beams. The study analyzes buildings with varying depths of coupling beams and heights to determine the critical slenderness ratio of the coupling beam that provides a response similar to a solid shear wall building. The analysis was performed using ETABS software and found that the performance of buildings with coupled shear walls depends on the depth of the coupling beam. Each building design requires a specific critical slenderness ratio for the coupling beam.
IRJET- Study on Shear Wall and Bracing in Irregular Structure and Regular Str...IRJET Journal
Ā
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It is a part of retrofitting i.e. repair, renovation, strengthening.
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Jacketing consists of added concrete with longitudinal and transverse reinforcement around the existing column.
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EFFECT OF SEISMIC LOAD ON REINFORCED CONCRETE MULTISTORY BUILDING FROM ECONOM...IAEME Publication
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design of a 20-storey reinforced concrete residential building from economical point
of view. This type of loading should be taken into considerations now in Iraq
especially after the earthquake of 7.3 magnitude that occurred in November 2017 near
the city of Halabja by about 31 kilometers. The same reinforced concrete multistory
building was designed twice; once with traditional gravity dead and live loading and
the second with adding earthquake loading in order to discuss the difference from
structural and economical points of view. A commercial package ETABS2018 was
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increase in the steel reinforcement amounts in columns, beams, slabs and shear walls
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the reinforcing steel amounts increased by about 327%, 165%, 40% and 91.3% for
columns, beams, slabs and shear walls, respectively. Therefore, cost was raised by
about 328%, 165%, 40% and 91.3% for columns, beams, slabs and shear walls,
respectively. It is worth to mention here that the maximum increase in main
reinforcement of beams was observed on the storey 10. Whereas, in slabs, the
maximum increase that was recorded in main steel reinforcement was happened from
the storey 8 to the building top. In columns, the main reinforcement increase was seen
on the 9th, 10th and 11th storeys. Finally, in shear walls, the main reinforcement
increase was seen in the 1
st
, 2
nd
and 3
rd
storey due to effect lateral shear forces
Comparative Study of Seismic Analysis of Building with Light Weight and Conve...Dr. Amarjeet Singh
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in construction instead of conventional material. Lightweight
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construction in seismic zone reduce the percentage of
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Post tensioned concrete walls & frames for seismic resistance
1. SEAOC 2008 CONVENTION PROCEEDINGS
Post-Tensioned Concrete Walls and Frames for SeismicResistance ā A Case Study of the David Brower Center
Mark Stevenson, CE
Leo Panian, SE
Mike Korolyk, CE
David Mar, SE
Tipping Mar + associates
Berkeley, CA
Introduction
This case-study describes an innovative application of posttensioned concrete construction in the new David Brower
Center urban mixed-use development.
Situated in the heart of downtown Berkeley, CA, within 1km
of the Hayward Fault, the new complex represents a model of
integrated sustainable design. Rated LEED Platinum by the
U.S. Green Building Council and named for David Brower,
one of the preeminent environmentalists of the 20th century,
the center will provide office and meeting space for
environmental advocacy and non-profit groups.
To protect the building against the high likelihood of a major
earthquake, the structure integrates a unique combination of
post-tensioned concrete walls and frames that improve
performance, limit damage, and make more efficient use of
construction materials.
The defining feature of this system is its unique self-centering
behavior, which virtually eliminates permanent postearthquake deformations. The hybrid system combines the
elasticity of the high-strength un-bonded tendons with the
energy dissipation capacity of the mild-steel reinforcement to
control the inelastic response of the structure.
The use of post-tensioning in concrete structures to resist
gravity loads is a well established technology with wide
application. Recent advances in design practice and analysis
techniques are demonstrating that post-tensioning also offers
significant cost and performance benefits when incorporated
into seismic resisting concrete walls and frames.
Properly proportioned, such a system provides improved
ductility and is less prone to physical damage during
earthquake shaking. Moreover, the post-tensioning provides a
significant strength enhancement, substantially reducing
quantities of conventional reinforcement in flexural members,
Figure 1 ā Project overview
1
2. resulting in more compact dimensions and improved
constructability.
Specialized concrete mixes, with high-volume replacement of
cement with blast-furnace slag, were also integrated into the
design to reduce the quantity of Portland cement: an energy
intensive material.
This case-study describes key issues related to the design,
analytical modeling, and construction of this novel hybrid
system.
Project Description
The project is a combination of four distinct elements: a 4story office building and conference center, a multi-unit
residential building, ground floor retail space, and an
underground parking garage. See Figures 1 and 2.
This study focuses on the David Brower Center office
structure, which, with its distinctive elongated bullet shape,
forms the northern boundary of the complex. Oxford Plaza is
a multi-unit residential building situated directly to the south
and is supported on a second-story PT podium slab over
ground floor retail space. The single level below-grade
parking covers the entire site.
The total floor area of the complex is 225,000 sq. ft. With
plan dimensions of approximately 62ā x 196ā, the Brower
Center comprises roughly 49,500 sq. ft. of space. The total
project construction cost was approximately $50M. The
Brower Center alone is estimated to cost around $15.3M.
The gravity system consists of concrete columns supporting 9
inch PT slabs. Longitudinal bays are spaced at 27 ft. Along
the short axis two 16 ft. bays flank a central 28 ft. bay.
The foundation consists of a mat slab between 2ā to 2ā-6ā in
thickness. Deep foundations were avoided by resolving
lateral system overturning forces into a moment couple
between the ground floor slab and the mat slab. Below the
ground floor, the walls and frames are designed to remain
elastic.
Seismicity and Sustainability
The site is near a major fault system capable of producing a
7.0+ magnitude earthquake. An earthquake of such intensity
is predicted to occur, with near certainty, within the next 30
years ā well within the expected lifespan of this structure. A
typical code-compliant building would be considered wellperforming if it remained standing and allowed safe
evacuation of the inhabitants after a major seismic event,
even if substantial structural damage occurred. It is often the
case in such instances that the primary structural system
retains sufficient residual strength to remain in service but
that residual drift and widespread damage to non-structural
components renders it unfit for continued use. Permanent
offsets can interfere with the functioning of doors, windows,
elevator shafts and other components to such an extent that
the structure must be demolished and rebuilt.
Clearly a major aspect of sustainable construction in this
setting is continued functionality of the structure after the
occurrence of a large earthquake. Protection of the
investment in energy and materials is a key āgreenā
construction goal.
Concrete and Carbon Footprint
The major component of embodied energy and related
ācarbon footprintā for a concrete structure is the cement used
in the concrete mix. Cement production is very energy
intensive and a significant source of global greenhouse-gas
emissions. Aggressive use of blast furnace slag, a waste
product of steel production, is estimated to have saved
1,000,000 lbs. of CO2 emissions.
Figure 2 ā Project overview
The David Brower Center incorporates a dual seismic force
resisting system, with two centrally located C-shaped cores
acting in conjunction with two transverse moment frames at
the ends of the building as described in Figure 3. The frames
are located outboard of the central core walls to control
torsional response. In the longitudinal direction the core walls
resist the entire seismic load.
2
Typical cement replacement ratios for the project ranged
from 50% for slabs, columns and walls to 70% for the mat
foundation. The large reduction in cement used was thus key
to achieving the project design goals of high material
efficiency along with reduced embodied energy and life-cycle
costs.
Design Approach
The design of the structure is based on the seismic loads
specified in the 2001 edition of the California Building Code,
(CBC, 2002) for dual concrete shear wall / moment frame
systems.
3. The unusual geometry and configuration of the building
required careful proportioning and relied on capacity design
principles to ensure that inelastic mechanisms would form in
a predictable and reliable manner. To verify and refine the
design of structural system, non-linear time-history
simulations were performed to predict the response of the
building.
Figure 3 ā Structural system
The moment frames and the core walls incorporate posttensioning and contribute to the re-centering effect.
Response of Post-tensioned Concrete Systems
The use of hybrid post-tensioned concrete for seismic
resistance is not unique to this application. Though not
widespread in practice, the advantages these systems can
provide are increasingly being exploited to improve the
seismic performance and efficiency of structures, (Panian,
Steyer, Tipping, 2007). The behavior of post-tensioned
flexural elements can be conceptualized by considering a
simplified cantilever supported by a rotational spring and
damper shown in Figure 5.
The response of the cantilever is characterized by the
superposition of two fundamental mechanisms of resistance:
a non-linear elastic restoring spring representing the effect of
the post-tensioning tendons, and a non-linear inelastic
yielding component representing the conventional
reinforcement. Both the tendons and the reinforcement
contribute to the overall flexural strength of the flexural
element. The mild steel reinforcement yields to dissipate
energy, while the unbounded tendons remain elastic to
provide a positive restoring force and center the structure
after inelastic response. This idealized flexural forcedeformation response of the cantilever as the superposition of
its components is described in Figure 4.
The elastic component, Figure 4a, represents the response
with the contribution of the post-tensioning only. Figure 4b,
represents the contribution of the mild steel reinforced
concrete section without the effect of the post-tensioning. As
seen in Figure 4c the hysteresis loop of a hybrid wall
containing mild steel and post-tensioning exhibits a flagshaped loop that results from the superposition of two
component curves.
The elastic restoring component is proportioned to be
somewhat larger than the yielding component, which means
that slightly more than half the total resistance is derived
from the post-tensioning. This ensures a favorable ārockingā
response and a consistent tendency to re-center following an
earthquake.
Plastic Hinge Mechanics
As in typical concrete flexural analysis, cross-sections are
assumed to remain plane throughout inelastic response.
Inelastic rotations of the hinge are estimated as the product of
the plastic hinge length and the curvature. Establishing
equilibrium forces for a concrete flexural element with unbonded post-tensioning takes a similar approach. However,
estimating the strain of the tendons requires consideration of
Figure 4 ā Hysteretic response of hybrid PT element
3
4. the kinematics of the entire member, because stress changes
in the tendons result only from the movement of the end
anchors. Strains in the un-bonded strands are distributed over
the entire tendon length, not just the length of the plastic
hinge.
critical to avoid the premature fracture of tendons and
crushing of concrete.
Key aspects of proportioning the flexural elements are as
follows (Panian, Steyer, Tipping, 2007):
ā¢
Adequate strength to meet code requirements,
ā¢
The proportion of flexural strength from PT vs. total
flexural strength roughly greater than 0.55, and
ā¢
Enough concrete area and strength to keep the
compression toes well-intact at maximum expected
curvature.
Recognizing and exploiting the overall symmetry of opposing
non-coupled C-shaped walls allowed a configuration of
tendons and reinforcing that would not have been otherwise
possible with an isolated asymmetric structure. The tendons
are placed in the flanges and mild-steel reinforcement is
concentrated at the flange tips to reduce compressive strains
on the concrete and tensile strains in the strands. This allowed
the optimization of the wall sections and enhanced the
ductility of the structure.
Nonlinear Response-History Analysis
To test the design under simulated earthquake shaking, a nonlinear time-response analysis (NLRHA) was performed using
spectrally-matched site-specific ground motion predictions.
The analysis was conducted using CSI Perform-3D. The
inelastic flexural behavior of the post-tensioned walls and
frames was modeled with inelastic fiber element sections.
Figure 5 ā Mechanism study
This means that as the cross-section reinforcement yields, the
tendons remain elastic, and are thus protected from premature
yielding.
If the moment provided by these tendons remains greater than
the plastic moment of the yielded reinforcement, the tendons
can close the plastic hinge, causing little or no residual
deformations.
Proportioning Reinforcement and PT
Proportioning the hybrid flexural elements requires that
specific attention be paid to the strains in the tendons and
concrete to ensure a stable failure mechanism. To promote
the desired mechanism and maximize system ductility, it is
4
The elements in the model were made of materials with the
capability to yield and generate hysteretic behavior to
estimate the expected behavior of the concrete, rebar and PT
components. The behavior of the un-bonded tendons is
achieved by connecting them only to the wall elements at the
top and bottom of the wall; these correspond to the locations
actual anchorage zones. The rebar and concrete elements, by
contrast, are connected at each floor level, which is analogous
to the real bonding and plastic hinge behavior.
The practical value of the NLRHA was evident both as a
design tool and as a verification tool. Preliminary models
allowed the design to be fine tuned, while the final analyses
provided confirmation that the design satisfied the
performance objectives.
The results of the NLRHA were used in conjunction with
capacity design principles (Priestley, Paulay, 1992 &
Priestley, Calvi, Kowalsky, 2007) to predict forces in
āprotectedā elements, eliminate non-ductile failure modes,
and ensure a stable flexural mechanism.
Maximum inter-story drifts are predicted to be 1.5% and
2.5% for the Design Basis Earthquake (DBE) and the
5. Maximum Capable Earthquake (MCE) respectively. Residual
drifts in each case were negligible.
The peak average strain in the PT tendons was significantly
less than the offset yield strain of 0.008 for the DBE
earthquake. For the MCE earthquake, the strains were slightly
above the yield point at the extreme wall tendons. The
reinforcement is expected to experience significant yielding
under both MCE and DBE motions, but fracture is not
anticipated for either hazard level. Maximum concrete strains
are predicted to remain less than 0.008, below the ultimate
confined concrete strain capacity of 0.010.
resisting systems, where the added imposed compressive
forces push concrete close to its ultimate crushing strain.
Careful detailing of lateral reinforcement is required to ensure
that ductile steel yielding rather than brittle concrete crushing
is the controlling failure mode. Figure 6 describes the core
wall reinforcing details at the plastic hinge location.
Construction Detailing
A critical aspect of seismic detailing for structural concrete is
confinement. Section ductility and good hysteretic behavior
require that core concrete retain its integrity under high
compressive strains and repeated load reversals. This
becomes even more critical in post-tensioned seismic
Figure 7 ā PT core wall construction showing anchor block-out
Given the size of vertical flexural bars in the core walls (#14
at base, #11 at hinge region) and the architectural desire to
minimize overall core dimensions, traditional hooked crossties were not practical in the first two stories of the cores.
Headed bars were used at the most congested sections. Their
compact shape allows them to be closely spaced while easily
engaging the intersections of horizontal and vertical bars.
Figure 6 ā PT core wall section
Figure 8 ā PT moment-frame construction
5
6. These were provided at 6ā o.c. in the boundary zones and
typically 12ā o.c. each way in the wall webs. See Figure 7.
The required vertical and horizontal reinforcing is curtailed
above the plastic hinge region, allowing confinement above
the third floor to be traditional hooked cross-ties. Splicing of
flexural reinforcement at and below the hinge zone was
achieved using Type II mechanical couplers. As these
couplers become large for #11 and #14 bars, it is important to
define their location and required stagger to avoid excessive
congestion. Even so, careful concrete placement and
consolidation is required at the densest locations.
bays. The relative shortness of the end bays required
significant rotational ductility and a high level of
confinement. With a typical beam dimension of 28 in (D) x
24 in (W), accommodation of PT ducts, wedge plates,
longitudinal and transverse reinforcing requires careful
layout. Figure 8 shows one of the frames under construction.
Detailed drawings of beam sections and elevations showing
each component drawn to scale were critical in determining
proper fit. See Figure 9.
The post-tensioning tendons consist of bundles of 0.6ā
diameter, individually sheathed and greased tendons in
corrugated metal ducts. This approach allows the ducts to be
cast in place and the tendons to be installed after all of the
concrete is placed. Bundles range in size from 11 to 17
strands that terminate in multi-strand anchorages.
Figure 10 ā Detail at moment frame PT anchor
Figure 9 ā PT moment-frame joint details
Detailing of the PT moment frames presented similar
challenges. The building geometry established a 3-bay
layout with a 28 ft. center bay flanked by two 16.5 ft. end
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Concrete confinement in the anchorage region begins with a
#5 spiral which is integral to the multi-strand casting.
Additional horizontal bars and cross ties in the anchorage
zone help to distribute the concentrated tendon reactions
across the full core section. Design of these added bars is
based on strut and tie modeling of the tendon forces.
7. Tendon stressing of the moment frames was straight forward.
A single multi-strand hydraulic jack was suspended by crane
at the exterior column face and the strands were stressed
together in one operation.
Figure 12 ā Exterior of PT moment frame
Figure 11 ā Stressing jack for wall tendons
The stressing operation for the vertical tendons in the core
walls was similar, but required a block-out at the base of the
walls to allow installation of the tendons. The bottom blockouts are located in the basement level, which is designed to
remain elastic. Mechanical couplers are used to splice
horizontal and vertical bars within the block-out. The blockouts are poured solid to complete the walls after the tendons
are stressed.
systems. Direct structural benefits include improved ductility,
reduced mild steel reinforcing and self-centering behavior.
The ability to eliminate residual drift represents a major
innovation in seismic design.
Additionally, savings in carbon footprint and greenhouse gas
emission were realized through integrating high-slag concrete
in the structural system. These characteristics played an
important role in meeting the sustainability goals of the
David Brower Center.
As the anchorages on top of the core and at the moment
frames are located in exterior members, corrosion protection
is a concern. Exterior weather caps over solid grouted anchor
pockets are the first line of defense. The tendon sheaths are
sealed to the cast fittings and internal ports allow grease to be
injected into the completed assembly to provide maximum
protection.
Summary
Several benefits can be realized by the introduction of posttensioned reinforcement to concrete seismic lateral resisting
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8. Acknowledgments
Architect:
Owner/Developer:
Contractor:
Solomon ETC
Equity Community Builders / RCD
Cahill
References
ICBO, California Building Code, California Code of
Regulations, Title 24, Part 2, Vol. 2, 2001 edition, Division
IV ā Earthquake Design, International Conference of
Building Officials, Whittier, California
Panian, L.; Steyer, M.; Tipping, S., āPost-Tensioned
Concrete Walls for Seismic Resistance,ā PTI Journal, July
2007, Vol. 5, number 1, Post-Tensioning Institute, Phoenix,
Arizona
Panian, L.; Steyer, M.; Tipping, S., āPost-Tensioned
Shotcrete Shearwalls,ā Concrete International, October
2007, Vol. 29, number 10, American Concrete Institute,
Farmington Hills, Michigan
Priestley, M.J.N.; Calvi, G.M.; Kowalsky, M.J., 2007,
āDisplacement Based Seismic Design of Structures,ā IUSS
Press, Pavia, Italy
Priestley, M.J.N.; Seible, F.; Calvi, G., 1996, āSeismic
Design and Retrofit of Bridgesā, John Wiley & Sons, New
York, NY
Paulay, T.; Priestley, M.J.N., 1992, āSeismic Design of
Reinforced Concrete and Masonry Buildings,ā John Wiley &
Sons, New York, NY, pp. 389-416
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