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Book Seismic Assessment and Retrofit of Reinforced Concrete Columns

Download or read book Seismic Assessment and Retrofit of Reinforced Concrete Columns written by Konstantinos G. Megalooikonomou and published by Cambridge Scholars Publishing. This book was released on 2019-02-27 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reinforced concrete columns play a very important role in structural performance. As such, it is essential to apply a suitable analytical tool to estimate their structural behaviour considering all failure mechanisms such as axial, shear, and flexural failures. This book highlights the development of a fiber beam-column element accounting for shear effects and the effect of tension stiffening through reinforcement-to-concrete bond, along with the employment of suitable constitutive material laws.

Book Hysteretic Modeling of Shear critical Reinforced Concrete Columns

Download or read book Hysteretic Modeling of Shear critical Reinforced Concrete Columns written by Tanmoy Chowdhury and published by . This book was released on 2007 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Prior studies have shown that older reinforced concrete buildings designed before the introduction of the modern seismic code in the early 1970s are vulnerable to damage and collapse during an earthquake. In particular, building columns did not have the lateral strength or ductility to withstand the demands imposed by the effects of a severe earthquake ground motion, and were often the most critical components of such earthquake damage-prone structures. They were typically characterized by insufficient and poorly detailed transverse reinforcement, widely spaced stirrups and low longitudinal reinforcement ratios. The focus of this research is to develop a suitable hysteretic model that would predict the lateral deformation behavior of lightly reinforced or shear-critical columns subjected to seismic and gravity loads. Tests of reinforced concrete columns under lateral loads have shown that the total drift stems from deformations owing to flexure, reinforcement slip, and shear. The monotonic response is initially established for the separate components in order to serve as a primary backbone curve for the cyclic force-displacement relationships. Existing analytical and experimental research on lightly reinforced columns is examined. This information is used, and when required, modified to ultimately develop a suitable overall hysteretic model that would accurately predict the lateral response of this class of columns with a limited computational effort. Cyclic models are developed for each deformation component that incorporate the strength, stiffness, and energy dissipation characteristics of the structural members. The total hysteretic response was derived by coupling flexure, reinforcement slip, and shear responses as springs in series. The behavior of a column is classified into one of five categories based on a comparison of the shear, yield, and flexural strengths. The expected behavior in each category determines rules that govern the combination of the deformation components. The proposed hysteretic model is calibrated against experimental results for correlation and verification studies. Overall, the model did a reasonable job of simulating the loaddeformation relationships of shear-critical columns. It provides a suitable platform to analyze older reinforced concrete buildings with a view to determining the amount of remediation necessary for satisfactory seismic performance.

Book Seismic Evaluation of Existing Reinforced Concrete Building Columns

Download or read book Seismic Evaluation of Existing Reinforced Concrete Building Columns written by Abraham Christopher Lynn and published by . This book was released on 2001 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Evaluating and Improving the ACI 318 19 Shear Strength Relationships for Seismic Design of Reinforced Concrete Columns

Download or read book Evaluating and Improving the ACI 318 19 Shear Strength Relationships for Seismic Design of Reinforced Concrete Columns written by Alex-Amirnezam Fakhroo and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ACI 318-19 provisions for computing the one-way shear capacity of non-prestressed reinforced concrete (RC) columns are primarily based on the results obtained from the RC beams. These equations were introduced in ACI 318-19 to account for the effects of the longitudinal reinforcement ratio, the depth of the column, and the applied axial load on the overall shear capacity. In this study, a column database was developed and used to evaluate the accuracy of the one-way shear provisions. Then, the ACI 318-19 shear capacity equations were evaluated by using the test results for non-prestressed RC columns. The results showed that these relationships significantly underpredict the actual shear capacity of the columns obtained from the test results. To improve the accuracy of the shear capacity equations, a new relationship is proposed and discussed in detail.

Book Seismic Evaluation of Reinforced Concrete Columns and Collapse of Buildings

Download or read book Seismic Evaluation of Reinforced Concrete Columns and Collapse of Buildings written by Muhammad Shadab Lodhi and published by . This book was released on 2012 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: There are a large number of reinforced concrete (RC) buildings in seismically active areas of the world that are not designed and constructed in accordance with modern seismic design provisions. These buildings are vulnerable to severe damage or collapse due to their low lateral displacement capacity and rapid degradation of shear strength during strong ground motions. Typically, columns in such buildings lack adequate strength and ductility in reverse cyclic loading and experience brittle shear failure and loss of axial load carrying capacity. To assess vulnerability to earthquake damage and decide on the required level of retrofit, expected behavior of the columns in terms of strength and deformation capacity must be evaluated. This can be achieved by estimating the load-deformation response considering all potential failure mechanisms associated with axial, flexure and shear behavior.

Book Seismic Design of Reinforced Concrete Buildings

Download or read book Seismic Design of Reinforced Concrete Buildings written by Jack Moehle and published by McGraw Hill Professional. This book was released on 2014-10-06 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complete coverage of earthquake-resistant concrete building design Written by a renowned seismic engineering expert, this authoritative resource discusses the theory and practice for the design and evaluation of earthquakeresisting reinforced concrete buildings. The book addresses the behavior of reinforced concrete materials, components, and systems subjected to routine and extreme loads, with an emphasis on response to earthquake loading. Design methods, both at a basic level as required by current building codes and at an advanced level needed for special problems such as seismic performance assessment, are described. Data and models useful for analyzing reinforced concrete structures as well as numerous illustrations, tables, and equations are included in this detailed reference. Seismic Design of Reinforced Concrete Buildings covers: Seismic design and performance verification Steel reinforcement Concrete Confined concrete Axially loaded members Moment and axial force Shear in beams, columns, and walls Development and anchorage Beam-column connections Slab-column and slab-wall connections Seismic design overview Special moment frames Special structural walls Gravity framing Diaphragms and collectors Foundations

Book Evaluation and Prediction of Shear Behavior of Reinforced Concrete Beam column Joints

Download or read book Evaluation and Prediction of Shear Behavior of Reinforced Concrete Beam column Joints written by Firat Alemdar and published by . This book was released on 2007 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Beam-column joints are one of the most critical elements of reinforced concrete moment resisting frames subjected to lateral seismic loading. The older reinforced concrete buildings designed before the introduction of modern seismic codes in the early 1970's, in general, do not meet the current design code requirements. In particular, the beam-column joints in such existing buildings do not have appropriate detailing which leads to insufficient lateral strength or ductility to withstand the effects of a severe earthquake loading. Therefore, evaluation of the lateral load carrying capacity of existing buildings for subsequent retrofit is very important for the safety of the buildings. The economical aspect should also be considered during the design of a structure which is only possible if the behavior of the structure during an earthquake can be predicted. The focus of this research is to evaluate the shear behavior of reinforced concrete beam-column joints and to develop a suitable model that would predict the lateral load carrying capacity. Previous experimental studies and results have shown that the shear strength of beam-column joints depends on several variables including concrete strength, axial load ratio, joint geometry joint transverse reinforcement ratio, and displacement ductility. However, the current codes include the effects of all of these parameters in beam-column joint design. Therefore, previous analytical research is examined and this information is used to develop a shear strength model. The proposed model is mainly based on the shear strength model for columns developed by Sezen and Moehle (2004). The proposed shear strength model is verified with experimental test results. Overall, the model did a reasonable job of predicting the shear strength of reinforced concrete beam-column joints. The proposed model provides a simply tool for the analysis of existing reinforced concrete buildings subjected to lateral loading and to determine the amount of remediation necessary for satisfactory seismic performance.

Book Further Investigation of a New RC Slab column Connection for Improved Seismic Performance of Multi story Buildings

Download or read book Further Investigation of a New RC Slab column Connection for Improved Seismic Performance of Multi story Buildings written by Austin Ryan Anderson and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete Filled Steel Tube (CFST) columns have several advantages over reinforced concrete columns in that: (1) the steel tube provides confinement of the concrete and reduces damage to the concrete core, (2) they possess very high shear capacities, (3) the steel tube is placed at the optimum location for flexural resistance, and (4) they sustain large drift demands without damage. CFSTs also accelerate construction since: (1) the steel tube acts as permanent formwork, (2) in a slab-column system, the columns and slabs may be cast simultaneously, (3) most of the internal reinforcement can be eliminated. Previously an experimental program was undertaken to investigate a proposed connection for use in flat-plate construction. The connection consists of steel rings on either side of the column with post-tensioned bolts to connect the rings and provide active confinement to the slab. The forces are transferred from the upper column to the lower column through reinforcement welded to the inside of the tube of the lower column. The ring also increases the critical perimeter for shear. A four-specimen program investigated the impact of the following design variables: (1) ring size, (2) number of bolts within the ring flange, and (3) bolts outside of the ring. A reference specimen using conventional stud-rail detailing was built. This experimental program aimed to further that research by investigating the effect of slab depth on the connection. In addition, two full-scale push-through tests were conducted to better understand the two-way shear behavior of the proposed connection. The conventional stud-rail connection sustained damage at low drift levels, which resulted in loss of strength. This behavior compromises the integrity and resilience of flat-plate buildings. The new connection provides drift capacities of 4% or greater before strength loss and mitigates damage, meeting the structural objective of integrity and resilience after a large seismic event. The research suggests that the ring dimension depends on both the column size and thickness of the slab. Test results showed better behavior with two rows of bolts on the ring flange. Although bolts outside the ring are beneficial, this detail was deemed impractical for new construction but may be viable for increasing shear capacity in retrofit design. Two-way shear strength resulted in a higher capacity for the connection with the larger ring flange and that ACI predictions of capacity were conservative.

Book Seismic Behavior of Reinforced Concrete Column to steel Beam RCS Connections with Special Configurations

Download or read book Seismic Behavior of Reinforced Concrete Column to steel Beam RCS Connections with Special Configurations written by Luis Bernardo Fargier-Gabaldón and published by . This book was released on 2005 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seismic Assessment and Retrofit of Reinforced Concrete Buildings

Download or read book Seismic Assessment and Retrofit of Reinforced Concrete Buildings written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2003-08-01 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: In most parts of the developed world, the building stock and the civil infrastructure are ageing and in constant need of maintenance, repair and upgrading. Moreover, in the light of our current knowledge and of modern codes, the majority of buildings stock and other types of structures in many parts of the world are substandard and deficient. This is especially so in earthquake-prone regions, as, even there, seismic design of structures is relatively recent. In those regions the major part of the seismic threat to human life and property comes from old buildings. Due to the infrastructure's increasing decay, frequently combined with the need for structural upgrading to meet more stringent design requirements (especially against seismic loads), structural retrofitting is becoming more and more important and receives today considerable emphasis throughout the world. In response to this need, a major part of the fib Model Code 2005, currently under development, is being devoted to structural conservation and maintenance. More importantly, in recognition of the importance of the seismic threat arising from existing substandard buildings, the first standards for structural upgrading to be promoted by the international engineering community and by regulatory authorities alike are for seismic rehabilitation of buildings. This is the case, for example, of Part 3: Strengthening and Repair of Buildings of Eurocode 8 (i. e. of the draft European Standard for earthquake-resistant design), and which is the only one among the current (2003) set of 58 Eurocodes attempting to address the problem of structural upgrading. It is also the case of the recent (2001) ASCE draft standard on Seismic evaluation of existing buildings and of the 1996 Law for promotion of seismic strengthening of existing reinforced concrete structures in Japan. As noted in Chapter 1 of this Bulletin, fib - as CEB and FIP did before - has placed considerable emphasis on assessment and rehabilitation of existing structures. The present Bulletin is a culmination of this effort in the special but very important field of seismic assessment and rehabilitation. It has been elaborated over a period of 4 years by Task Group 7.1 Assessment and retrofit of existing structures of fib Commission 7 Seismic design, a truly international team of experts, representing the expertise and experience of all the important seismic regions of the world. In the course of its work the team had six plenary two-day meetings: in January 1999 in Pavia, Italy; in August 1999 in Raleigh, North Carolina; in February 2000 in Queenstown, New Zealand; in July 2000 in Patras, Greece; in March 2001 in Lausanne, Switzerland; and in August 2001 in Seattle, Washington. In October 2002 the final draft of the Bulletin was presented to public during the 1st fib Congress in Osaka. It was also there that it was approved by fib Commission 7 Seismic Design. The contents is structured into main chapters as follows: 1 Introduction - 2 Performance objectives and system considerations - 3 Review of seismic assessment procedures - 4 Strength and deformation capacity of non-seismically detailed components - 5 Seismic retrofitting techniques - 6 Probabilistic concepts and methods - 7 Case studies