A Rocking Spine For Enhanced Seismic Performance Of Concrete Buildings With Infills
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A Rocking Spine For Enhanced Seismic Performance Of Concrete Buildings With Infills
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Author : Henry Verjil Burton
language : en
Publisher:
Release Date : 2008
A Rocking Spine For Enhanced Seismic Performance Of Concrete Buildings With Infills written by Henry Verjil Burton and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
Reinforced concrete frames with infill panels is a commonly used building system in many moderate and high seismic regions around the world, particularly in developing countries. In some cases, the frames are designed to resist earthquake loads but the infill panels are rarely ever incorporated in the structural design. Moreover, the layout of the infill can have severe negative effects on seismic performance, which is also seldom considered. This research utilizes state-of-the-art performance-based earthquake engineering and computational modeling methods to develop a novel technique envisioned as a cost-effective approach to improving the seismic collapse safety in infill frame buildings. The proposed technique uses strong, stiff structural spines that resist earthquake effects through rocking action. The rocking spine system is applicable to both retrofit and new design; however, this work is primarily focused on the latter. The primary sources of overturning resistance are the gravity loads acting directly on the spine and the restoring forces transferred to the spine through outrigger action of adjacent structural members. These include beams framing into the spine and the infill panels constructed in the adjacent bays parallel and orthogonal to the spine. The use of rocking as the primary yielding mechanism reduces the required level of detailing that would otherwise be required in ductile concrete frames, which make the spine infill frame more practical and economical to construct. Additional material and labor cost savings can be realized for taller buildings since deep foundations are not required for the spine system. The project is executed in three phases that focused on the component, building and community scales.
Proceedings Of The Canadian Society For Civil Engineering Annual Conference 2023 Volume 7
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Author : Serge Desjardins
language : en
Publisher: Springer Nature
Release Date : 2024-09-14
Proceedings Of The Canadian Society For Civil Engineering Annual Conference 2023 Volume 7 written by Serge Desjardins and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-09-14 with Technology & Engineering categories.
This book comprises the proceedings of the Annual Conference of the Canadian Society for Civil Engineering 2023. The contents of this volume focus on the specialty track in materials with topics on recycled materials, concrete durability, geopolymers, alkali-activated and other alternative binders, fiber-reinforced and engineered cementitious composites, advanced composite materials, ultra-high-performance materials, and innovative and emerging materials, among others. This volume will prove a valuable resource for researchers and professionals.
Establishing Capacity And Demand Factors For Force Controlled Components In A Rocking Spine System For Reinforced Concrete Frames With Infills Using A Reliability Based Method
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Author : Ni Made Novia Kusumayani
language : en
Publisher:
Release Date : 2017
Establishing Capacity And Demand Factors For Force Controlled Components In A Rocking Spine System For Reinforced Concrete Frames With Infills Using A Reliability Based Method written by Ni Made Novia Kusumayani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
A reinforced concrete frame with rocking spine system is evaluated using reliability-index method with main objective of establishing the load and resistance factors for the force-controlled components. A nonlinear structural model of a six-bay six-story concrete frame building with stiff infill panels idealized as compression only struts was constructed in OpenSees. Spine-infills, spine-beams, and spine-columns, are considered as force-controlled components, while non-spine infills and adjacent beams are considered as deformation-controlled components. The model is evaluated with 44 ground motions through Incremental Dynamic Analysis (IDA) to determine the demands in the force-controlled components. The model was also evaluated through response spectrum analysis to define the system's yield modification factor, , which is used along with hazard curve to obtain the reliability index of the system, . The capacity,,and demand,factors are calculated by defining the probability of demand surpassing capacity in 50 years equal to 0.05%, 0.1%, 0.2%, 0.5%, and 1%. The results show that the decreases as and increases. The capacity and demand factors of spine-infill struts, spine-beams, and spine-columns for 0.1% P(D>C)50 years are: ;; ; respectively.
Seismic Performance Of Concrete Buildings
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Author : Liviu Crainic
language : en
Publisher: CRC Press
Release Date : 2012-12-10
Seismic Performance Of Concrete Buildings written by Liviu Crainic and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-10 with Technology & Engineering categories.
This book examines and presents essential aspects of the behavior, analysis, design and detailing of reinforced concrete buildings subjected to strong seismic activity. Seismic design is an extremely complex problem that has seen spectacular development in the last decades. The present volume tries to show how the principles and methods of earthquake engineering can be applied to seismic analysis and design of reinforced concrete buildings. The book starts with an up-to-date presentation of fundamental aspects of reinforced concrete behavior quantified through constitutive laws for monotonic and hysteretic loading. Basic concepts of post-elastic analysis like plastic hinge, plastic length, fiber models, and stable and unstable hysteretic behaviour are, accordingly, defined and commented upon. For a deeper understanding of seismic design philosophy and of static and dynamic post-elastic analysis, seismic behavior of different types of reinforced concrete structures (frames, walls) is examined in detail. Next, up-to-date methods for analysis and design are presented. The powerful concept of structural system is defined and systematically used to explain the response to seismic activity, as well as the procedures for analysis and detailing of common building structures. Several case studies are presented. The book is not code-oriented. The structural design codes are subject to constant reevaluation and updating. Rather than presenting code provisions, this book offers a coherent system of notions, concepts and methods, which facilitate understanding and application of any design code. The content of this book is based mainly on the authors’ personal experience which is a combination of their teaching and research activity as well as their work in the private sector as structural designers. The work will serve to help students and researchers, as well as structural designers to better understand the fundamental aspects of behavior and analysis of reinforced concrete structures and accordingly to gain knowledge that will ensure a sound design of buildings.
Capacity Design And Topology Optimization Of Rocking Spine Systems For Nonlinear Earthquake Response
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Author : Amory Adrien Martin
language : en
Publisher:
Release Date : 2020
Capacity Design And Topology Optimization Of Rocking Spine Systems For Nonlinear Earthquake Response written by Amory Adrien Martin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Rocking spine systems are innovative earthquake-resistant structural systems that dampen seismic shaking through uplift at the base and confine damage to energy-dissipating fuses, thereby significantly reducing the potential of building downtime. Currently, United States building codes and standards provide very limited design guidelines for such systems. This thesis focuses on developing procedures and algorithms for design and optimization of rocking spine systems under nonlinear earthquake response. A new capacity design procedure, the modified modal superposition (MMS) method, is developed for the seismic design of rocking spine systems. The methodology uses an efficient elastic response spectrum analysis to approximate the nonlinear earthquake response through (1) modified boundary conditions to simulate rocking at maximum considered earthquake (MCE) level and (2) a first mode inelastic reduction factor. The methodology is extended to coupled and stacked rocking braced frames, as well as strongback systems, with various hysteretic and viscous dampers. Using nonlinear dynamic analyses on a set of seven archetype frames ranging from 6 to 18 stories, the MMS procedure is shown to accurately capture higher modes effects and estimate axial brace and column forces. A reliability analysis conducted supports applying a load amplification factor of 1.3 for scaling the MMS seismic forces to design the steel braced frame as force-controlled components. A new dynamic topology optimization methodology, called the sum of modal compliances (SMC), is introduced for seismic loading. Recently developed dynamic topology optimization procedures for linear elastic response in the frequency domain are compared and contrasted. The novel procedure is applied to the design of lateral bracing system of high-rise buildings for various earthquake hazards and yields important considerations of the influence of higher modes on the overall dynamic response of the system. The efficiency of the SMC optimization algorithm is demonstrated on a 3D high-rise building with over one million degrees of freedom. Using the modified modal superposition as inspiration, the dynamic topology optimization procedure is extended to design of the elastic spine in rocking braced frames for nonlinear earthquake response. The extruded optimized bracing pattern is compared to a conventional X-bracing system using nonlinear dynamic analyses. An optimization framework is proposed for selecting the number, location and properties of nonlinear dampers in stacked rocking systems, where the total overturning moment in the spine is minimized, subjected to interstory drift and hinge rotation constraints. A ground motion selection routine is developed to facilitate the optimization by estimating the median dynamic response under earthquakes. Algorithmic procedures are developed to solve the structural optimization problem using both modified sequential linear programming (SLP) method and particle swarm optimization (PSO). On a 20-story dual rocking hinge case study, the SLP algorithm is shown to converge to the optimum with less than 40 nonlinear dynamic analyses compared to over 4,000 for an exhaustive search. For a 20-story stacked rocking system with N arbitrary hinges, the SLP optimization yields three rocking joints, whereby the total overturning moment in the spine is reduced by half compared to the initial design, while maintaining drift limits below 2.5% at MCE level. Overall, this thesis introduces design and optimization procedures for both the rocking spine and nonlinear articulated hinges. This research project demonstrates the advantages of rocking spine systems for improved seismic performance and introduces novel optimization algorithms for structural design under earthquake loading.
Seismic Retrofit Of Unreinforced Masonry Infills In Non Ductile Reinforced Concrete Frames Using Engineered Cementitious Composites
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Author : Marios Kyriakides
language : en
Publisher:
Release Date : 2011
Seismic Retrofit Of Unreinforced Masonry Infills In Non Ductile Reinforced Concrete Frames Using Engineered Cementitious Composites written by Marios Kyriakides and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Masonry infills in non-ductile reinforced concrete frames can be found in many places around the world, such as the western United States, China, and in countries of the Mediterranean region. There is strong laboratory and field evidence that masonry infills can improve the performance of reinforced concrete structures, as demonstrated in the 1994 Northridge earthquake. However, many masonry-infilled reinforced concrete buildings suffered catastrophic failures in recent earthquakes such as in the 1999 Kocaeli earthquake in Turkey and the 2008 Sichuan earthquake in China, causing the death of hundreds of people and affecting the lives of millions. A new seismic retrofit technique specifically for unreinforced masonry infills in non-ductile reinforced concrete frames has been developed. The technique uses a sprayable, ductile fiber-reinforced cement based material referred to as Engineered Cementitious Composites, or ECC. Small-scale component experiments including compression tests of masonry prisms and flexural tests of masonry beams retrofitted with different ECC retrofit schemes were conducted to investigate the impact of the retrofit on the performance of masonry in terms of strength, stiffness and ductility. The findings of the small-scale component experiments were used for the development of the ECC retrofit design. Four 1/5-scale masonry infilled non-ductile reinforced frames - one with an unretrofitted masonry wall and three with retrofitted masonry walls - were subjected to quasi-static, in-plane cyclic loading to validate the retrofit design. It was found that when a thin layer of ductile cement-based retrofit is applied to the masonry wall and properly tied into the concrete frame, the deformation capacity of the infilled frame is increased 10 times through a rocking motion. In collaboration with researchers from The University of Colorado, at Boulder and The University of California, San Diego, the retrofit design was evaluated through a quasi-static, in-plane cyclic test of a 2/3-scale masonry infilled non-ductile reinforced concrete frame and a dynamic shake-table test of a 2/3-scale, three-story, two-bay masonry infilled non-ductile reinforced concrete frame. These tests demonstrated that the ECC retrofit can significantly improve the performance of this type of structure under cyclic loads and seismic excitation. Existing analytical models for the prediction of the lateral strength and failure mode of masonry infilled reinforced concrete frames subjected to in-plane lateral load are evaluated through a limit analysis method. New analytical models for such structures with ECC retrofitted masonry walls are proposed. Two-dimensional non-linear finite element analyses using two different micro-modeling approaches are used to simulate unreinforced masonry beams retrofitted with a thin layer of ECC under four-point bending. In a detailed approach each material is modeled independently and in a simplified approach, expanded brick units with zero thickness mortar elements are used. The adequacy of these models to capture the experimental response of ECC strengthened masonry beams under out-of-plane bending is examined. The impact of the amount and location of reinforcement in the ECC layer, and of the use of anchors as a method of improvement of the bond between the ECC layer and the masonry surface is also examined through simulation. Two-dimensional non-linear finite element analyses are conducted to asses the ability of various smeared and discrete crack modeling approaches in a commercial finite element program for capturing the response of masonry infilled non-ductile reinforced concrete frames. A methodology for simulating this type of structures with ECC retrofitted walls in two dimensions is also presented.
Performance Based Seismic Design Of Concrete Structures And Infrastructures
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Author : Plevris, Vagelis
language : en
Publisher: IGI Global
Release Date : 2017-02-14
Performance Based Seismic Design Of Concrete Structures And Infrastructures written by Plevris, Vagelis and has been published by IGI Global this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-02-14 with Technology & Engineering categories.
Solid design and craftsmanship are a necessity for structures and infrastructures that must stand up to natural disasters on a regular basis. Continuous research developments in the engineering field are imperative for sustaining buildings against the threat of earthquakes and other natural disasters. Performance-Based Seismic Design of Concrete Structures and Infrastructures is an informative reference source on all the latest trends and emerging data associated with structural design. Highlighting key topics such as seismic assessments, shear wall structures, and infrastructure resilience, this is an ideal resource for all academicians, students, professionals, and researchers that are seeking new knowledge on the best methods and techniques for designing solid structural designs.
Seismic Design Of Reinforced And Precast Concrete Buildings
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Author : Robert E. Englekirk
language : en
Publisher: John Wiley & Sons
Release Date : 2003-03-10
Seismic Design Of Reinforced And Precast Concrete Buildings written by Robert E. Englekirk and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003-03-10 with Technology & Engineering categories.
* Presents the basics of seismic-resistant design of concrete structures. * Provides a major focus on the seismic design of precast bracing systems.
Displacement Based Seismic Design Of Reinforced Concrete Buildings
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Author : fib Fédération internationale du béton
language : en
Publisher: fib Fédération internationale du béton
Release Date : 2003
Displacement Based Seismic Design Of Reinforced Concrete Buildings written by fib Fédération internationale du béton and has been published by fib Fédération internationale du béton this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Technology & Engineering categories.
A brief summary of the history of seismic design as given in chapter 1, indicates that initially design was purely based on strength or force considerations. When the importance of displacement, however, became better appreciated, it was attempted to modify the existing force-based approach in order to include considerations of displacement, rather than to totally reconsider the procedure on a more rational basis. In the last decade, then, several researchers started pointing out this inconsistency, proposing displacement-based approaches for earthquake engineering evaluation and design, with the aim of providing improved reliability in the engineering process by more directly relating computed response and expected structural performance. The main objective of this report is to summarize, critically review and compare the displacement - based approaches proposed in the literature, thus favouring code implementation and practical use of rational and reliable methods. Chapter 2 Seismic performance and design objectives of this report introduces concepts of performance levels, seismic hazard representation, and the coupling of performance and hazard to define performance objectives. In fact, for displacement analysis to be relevant in the context of performance-based design, the structural engineer must select appropriate performance levels and seismic loadings. A critical review of some engineering limit states appropriate to the different performance levels is therefore proposed. In chapter 3 Conceptual basis for displacement-based earthquake resistant design, the fundamental principles associated with displacement of the ground during an earthquake and the effects, in terms of displacement, in the structure, are reviewed. The historical development guides the presentation with a review of general linear and nonlinear structural dynamics principles, general approaches to estimate displacement, for both ground and structure, and finally a general presentation of the means to measure and judge the appropriateness of the displacements of the structure in section. Chapter 4 Approaches and procedures for displacement-based design can be somehow considered the fundamental part of the report, since a critical summary of the displacement - based approaches proposed by different researchers is presented there. Displacement - based design may require specific characterization of the input ground motion, a topic addressed in Chapter 5 Seismic input. In general, various pertinent definitions of input motion for non-code format analysis are included, while peak ground parameters necessary for code base shear equations are only addressed as needed for the definition of motion for analysis. Chapter 6 Displacement capacity of members and systems addresses the fundamental problem of evaluating the inelastic displacement capacity of reinforced concrete members and realistic values of their effective cracked stiffness at yielding, including effects of shear and inclined cracking, anchorage slip, bar buckling and of load cycling. In Chapter 7 Application and evaluation of displacement-based approaches, some of the many different displacement based design procedures briefly introduced in Chapter 4 are applied to various case studies, identifying and discussing the difficulties a designer may encounter when trying to use displacement based design. Results for five different case studies designed in accordance with eight different displacement based design methods are presented. Although in general case studies are considered a useful but marginal part of a state of the art document, in this case it has to be noted that chapter 7 is possibly the most innovative and fundamental part of the whole report. The conclusions of chapter 7 are the fundamental and essential conclusions of the document and allow foreseeing a bright future for displacement - based design approaches. The state-of-art report has been elaborated over a period of 4 years by Task Group 7.2 Displacement-based design and assessment of fib Commission 7Seismic design, a truly international team of experts, representing the expertise and experience of all the important seismic regions of the world. In October 2002 the final draft of the Bulletin was presented to the public during the 1st fibCongress in Osaka. It was also there that it was approved by fib Commission 7Seismic Design.
Earthquake Resilient Tall Reinforced Concrete Buildings At Near Fault Sites Using Base Isolation And Rocking Core Walls
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Author : Vladimir Calugaru
language : en
Publisher:
Release Date : 2013
Earthquake Resilient Tall Reinforced Concrete Buildings At Near Fault Sites Using Base Isolation And Rocking Core Walls written by Vladimir Calugaru and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
This dissertation pursues three main objectives: (1) to investigate the seismic response of tall reinforced concrete core wall buildings, designed following current building codes, subjected to pulse type near-fault ground motion, with special focus on the relation between the characteristics of the ground motion and the higher-modes of response; (2) to determine the characteristics of a base isolation system that results in nominally elastic response of the superstructure of a tall reinforced concrete core wall building at the maximum considered earthquake level of shaking; and (3) to demonstrate that the seismic performance, cost, and constructability of a base-isolated tall reinforced concrete core wall building can be significantly improved by incorporating a rocking core-wall in the design. First, this dissertation investigates the seismic response of tall cantilever wall buildings subjected to pulse type ground motion, with special focus on the relation between the characteristics of ground motion and the higher-modes of response. Buildings 10, 20, and 40 stories high were designed such that inelastic deformation was concentrated at a single flexural plastic hinge at their base. Using nonlinear response history analysis, the buildings were subjected to near-fault seismic ground motions as well as simple close-form pulses, which represented distinct pulses within the ground motions. Euler-Bernoulli beam models with lumped mass and lumped plasticity were used to model the buildings. The response of the buildings to the close-form pulses fairly matched that of the near-fault records. Subsequently, a parametric study was conducted for the buildings subjected to three types of close-form pulses with a broad range of periods and amplitudes. The results of the parametric study demonstrate the importance of the ratio of the fundamental period of the structure to the period of the pulse to the excitation of higher modes. The study shows that if the modal response spectrum analysis approach is used--considering the first four modes with a uniform yield reduction factor for all modes and with the square root of sum of squares modal combination rule--it significantly underestimates bending moment and shear force responses. A response spectrum analysis method that uses different yield reduction factors for the first and the higher modes is presented. Next, this dissertation investigates numerically the seismic response of six seismically base-isolated (BI) 20-story reinforced concrete buildings and compares their response to that of a fixed-base (FB) building with a similar structural system above ground. Located in Berkeley, California, 2 km from the Hayward fault, the buildings are designed with a core wall that provides most of the lateral force resistance above ground. For the BI buildings, the following are investigated: two isolation systems (both implemented below a three-story basement), isolation periods equal to 4, 5, and 6 s, and two levels of flexural strength of the wall. The first isolation system combines tension-resistant friction pendulum bearings and nonlinear fluid viscous dampers (NFVDs); the second combines low-friction tension-resistant cross-linear bearings, lead-rubber bearings, and NFVDs. The designs of all buildings satisfy ASCE 7-10 requirements, except that one component of horizontal excitation is used in the two-dimensional nonlinear response history analysis. Analysis is performed for a set of ground motions scaled to the design earthquake (DE) and to the maximum considered earthquake (MCE). At both the DE and the MCE, the FB building develops large inelastic deformations and shear forces in the wall and large floor accelerations. At the MCE, four of the BI buildings experience nominally elastic response of the wall, with floor accelerations and shear forces being 0.25 to 0.55 times those experienced by the FB building. The response of the FB and four of the BI buildings to four unscaled historical pulse-like near-fault ground motions is also studied. Finally, this dissertation investigates the seismic response of four 20-story buildings hypothetically located in the San Francisco Bay Area, 0.5 km from the San Andreas fault. One of the four studied buildings is fixed-base (FB), two are base-isolated (BI), and one uses a combination of base isolation and a rocking core wall (BIRW). Above the ground level, a reinforced concrete core wall provides the majority of the lateral force resistance in all four buildings. The FB and BI buildings satisfy requirements of ASCE 7-10. The BI and BIRW buildings use the same isolation system, which combines tension-resistant friction pendulum bearings and nonlinear fluid viscous dampers. The rocking core-wall includes post-tensioning steel, buckling-restrained devices, and at its base is encased in a steel shell to maximize confinement of the concrete core. The total amount of longitudinal steel in the wall of the BIRW building is 0.71 to 0.87 times that used in the BI buildings. Response history two-dimensional analysis is performed, including the vertical components of excitation, for a set of ground motions scaled to the design earthquake and to the maximum considered earthquake (MCE). While the FB building at MCE level of shaking develops inelastic deformations and shear stresses in the wall that may correspond to irreparable damage, the BI and the BIRW buildings experience nominally elastic response of the wall, with floor accelerations and shear forces which are 0.36 to 0.55 times those experienced by the FB building. The response of the four buildings to two historical and two simulated near-fault ground motions is also studied, demonstrating that the BIRW building has the largest deformation capacity at the onset of structural damage.