Assessment of Seismic Collapse Uncertainties of Steel Moment-resisting Frames by Means of Single-degree-of-freedom Systems PDF Download

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Languages : en
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Author: Fadzli Mohamed Nazri
Publisher: Penerbit USM
ISBN: 9838618942
Category : Architecture
Languages : en
Pages :

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This research book presents the fundamental work related to the prediction of collapse load for a moment-resisting steel frame (MRSF) subjected to earthquake forces.It demonstrates the extensive work in nonlinear analysis with particular reference to pushover analysis (POA) and incremental dynamic analysis (IDA), and deliberates at length the historical background for each method. More importantly, the book simplifies the collapse prediction process of a structure based on analytical expression. In addition, this book describes the MRSF which was designed according to Eurocode(s). This bookserves as a guide and reference for practitioners and students. Universiti Sains Malaysia, Penerbit Universiti Sains Malaysia

Author: Ahmed Elkady
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ISBN:
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Languages : en
Pages :

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"In the context of Performance-Based Earthquake Engineering, there is an increasing need to quantify the collapse resistance of frame buildings under severe ground-motion shaking. The primary objective of this thesis is to advance, through experimental and analytical research, knowledge on the collapse risk assessment of steel frame buildings with steel moment-resisting frames (MRFs) designed in highly seismic regions in North America. Emphasis is placed on the characterization of the steel column hysteretic behaviour as well as the composite floor action and the destabilizing effects of the gravity framing system of steel frame buildings with steel MRFs. The dynamic stability of beam-columns that utilize deep and slender wide-flange cross sections is investigated through full-scale experimental testing. Some of the unique features of the experimental program involve realistic boundary conditions, unidirectional and bidirectional lateral loading and the use of various types of lateral loading protocols. The experimental data provide insight on the damage progression and deteriorating mechanisms observed in wide-flange beam-columns. The hysteretic behaviour of a wide range of cross-sections is further evaluated through a corroborating finite element (FE) parametric study. The findings of the coordinated experimental and analytical research are used to proposed recommendations for the seismic design of steel beam-columns in steel MRFs. A comprehensive system-level analytical study is then conducted in order to evaluate the collapse risk of steel frame buildings with special moment-resisting frames (SMFs) as per ASCE (2010) and Type D Ductile steel MRFs per NBCC (2010). The contributions of the composite floor slab and the gravity framing system are included in the analytical model representations of the steel frame buildings. These contributions have been historically ignored in prior analytical studies. In that respect, a practical approach is developed for modeling (a) the non-symmetric hysteretic behaviour of composite steel beams and panel zones as part of fully-restrained beam-to-column connections; and (b) the hysteretic behaviour of steel beams as part of conventional single-plate shear-tab beam-to-column connections. The collapse risk of typical steel frame buildings with steel MRFs is evaluated based on advanced collapse metrics such as the mean annual frequency of collapse. Based on the findings of the comprehensive system-level analytical study, the strong-column/weak-beam ratio that is typically used in the seismic design of steel MRFs is re-assessed such that a uniform probability of collapse can be achieved over the life expectancy of the steel frame buildings. A new definition of system overstrength (i.e., dynamic overstrength factor) is also proposed." --

Author: Omid Ahmadi
Publisher:
ISBN: 9781369338256
Category :
Languages : en
Pages : 242

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Structures are built where active faults may be in close proximity. The probability of collapse of a 4-story low-rise building with perimeter SC-MRFs subjected to near-field ground motions was studied and compared to the results for far-field ground motions. IDA are performed using an ensemble of 56 near-field ground motions. The results show that the SC-MRF built close to active faults has less collapse resistance in contrast to the one built in seismic zones away from active faults. The structure has larger spectral acceleration for near-field ground motions than far-field ground motions at the fundamental period, leading to excessive inelastic deformations that cause structure collapse earlier. The results obtained, however, show that an acceptable margin against collapse is still achieved and therefore indicate a potential for an SC-MRF to be used in seismic zones with active near-field faults.

Author: James L. Martin
Publisher: CRC Press
ISBN: 1138000868
Category : Science
Languages : en
Pages : 5742

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Focusing on fundamental principles, Hydro-Environmental Analysis: Freshwater Environments presents in-depth information about freshwater environments and how they are influenced by regulation. It provides a holistic approach, exploring the factors that impact water quality and quantity, and the regulations, policy and management methods that are necessary to maintain this vital resource. It offers a historical viewpoint as well as an overview and foundation of the physical, chemical, and biological characteristics affecting the management of freshwater environments. The book concentrates on broad and general concepts, providing an interdisciplinary foundation. The author covers the methods of measurement and classification; chemical, physical, and biological characteristics; indicators of ecological health; and management and restoration. He also considers common indicators of environmental health; characteristics and operations of regulatory control structures; applicable laws and regulations; and restoration methods. The text delves into rivers and streams in the first half and lakes and reservoirs in the second half. Each section centers on the characteristics of those systems and methods of classification, and then moves on to discuss the physical, chemical, and biological characteristics of each. In the section on lakes and reservoirs, it examines the characteristics and operations of regulatory structures, and presents the methods commonly used to assess the environmental health or integrity of these water bodies. It also introduces considerations for restoration, and presents two unique aquatic environments: wetlands and reservoir tailwaters. Written from an engineering perspective, the book is an ideal introduction to the aquatic and limnological sciences for students of environmental science, as well as students of environmental engineering. It also serves as a reference for engineers and scientists involved in the management, regulation, or restoration of freshwater environments.

Author: Joseph Gilroy
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Recent research has investigated a low damage seismic design concept for steel moment resisting frames (MRFs): the moment resisting fuse connection. Fuse connections are moment resisting connections that yield prior to the beam or column they connect. The connection acts as an easily repairable structural fuse of the seismic system instead of the beam, which is the typical fuse in a steel moment resisting frame designed to resist seismic loads, which can be very challenging and costly to repair after an earthquake. In most proposed fuse connections, energy dissipation is achieved by means of connection component yielding or friction slip. In AISC 358-16 (AISC, 2016c), the first prequalified fuse connection was added to the specification: the Simpson Strong-TieTM Yield-Link® (SST-YL) connection. Although the connection has shown sufficient strength and ductility at large levels of drift to reach prequalified status, there is some concern that steel MRFs with optimized fuse connections will not have the typical overstrength of traditional steel MRFs, which are usually controlled by drift limits rather than strength requirements. This concern raises the question: Are steel moment resisting frames with fuse connections adequately designed to prevent sidesway collapse during earthquakes when using typical seismic performance factors (R = 8, C [subscript d] = 5.5, and Ω0 = 3.0) for steel special moment resisting frames (SMRFs)? To investigate this concept, four three-bay steel special moment resisting frames with fuse connections were designed using provisions in ASCE7-16 (ASCE, 2017), AISC 341-16 (AISC, 2016a), AISC 360-16 (AISC, 2016b), and AISC 358-16s20 (AISC, 2020) with steel SMRF seismic performance factors. These frames were 2 stories, 4 stories, 6 stories, and 8 stories in height. These four archetypes were also redesigned with modified capacity design requirements more comparable to typical steel MRFs for a total of four design cases. These designs were evaluated using the FEMA P-695 methodology (FEMA, 2009) to determine if they have adequate collapse capacity. Different post-yield behaviors and failure criteria were modeled to determine their effect on system collapse capacity. Nonlinear pushover and response history analyses were done using OpenSEES (McKenna et al., 2010). The results of this investigation support that the seismic performance factors for typical SMRF frames are appropriate for use in SMRFs with fuse connections. However, there are several sources of uncertainty that require further investigation and research to determine to what extent this conclusion is accurate, particularly for new fuse connections that may be proposed. Suggestions for future research into numerical modeling and analysis of SMRFs with fuse connections are presented

Author: George Deodatis
Publisher: CRC Press
ISBN: 1315884887
Category : Technology & Engineering
Languages : en
Pages : 1112

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Safety, Reliability, Risk and Life-Cycle Performance of Structures and Infrastructures contains the plenary lectures and papers presented at the 11th International Conference on STRUCTURAL SAFETY AND RELIABILITY (ICOSSAR2013, New York, NY, USA, 16-20 June 2013), and covers major aspects of safety, reliability, risk and life-cycle performance of str

Author: Federico Mazzolani
Publisher: CRC Press
ISBN: 1482271346
Category : Architecture
Languages : en
Pages : 516

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A state-of-the-art summary of recent developments in the behaviour, analysis and design of seismic resistant steel frames. Much more than a simple background volume, it gives the most recent results which can be used in the near future to improve the codified recommendations for steel structures in seismic zones. It contains new material which cann

Author: Yusuke Suzuki
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"Capacity design principles have reduced the earthquake-induced collapse risk in steel frame buildings designed in seismic regions. Experiments suggest that the steel column behaviour may be significantly compromised due to member and local geometric instabilities, thereby increasing the associated collapse risk and likelihood of building demolition due to residual deformations. The High Yield Point (HYP400) steel is a steel material that has a higher yield stress and notch toughness but less strain hardening than conventional mild steels. HYP400 steel could enhance capacity design principles, such as the strong-column-weak-beam (SCWB) ratio when they are utilized in steel columns and potentially increase the collapse capacity of steel moment resisting frames (MRFs) under earthquake shaking. This thesis advances the state-of-knowledge through a multi-scale (from material to system) level study to assess the potential use of high-performance steel materials in minimizing earthquake-induced collapse of steel MRFs. The primary focus is on the characterization of the collapse behaviour of HYP400 and conventional steel hollow square section (HSS) columns by means of experimental testing and corroborating numerical simulations. Dual-parameter collapse-consistent loading histories (i.e., axial load and lateral drift demands) are developed to better quantify the flexural and axial demands in both interior and end columns in steel MRFs. These protocols reflect the asymmetric drifting of a building in one primary loading direction prior to dynamic instability ("ratcheting"). They also reflect the seismic demands imposed into steel columns within a steel MRF subjected to near-fault and long-duration ground motions. A landmark experimental program is conducted that characterizes the collapse behaviour of wide-flange and HSS steel columns under cyclic loading. The experimental program highlights the differences in the seismic demands and failure modes observed in steel columns depending on the imposed lateral and axial loading history, expected ground motion characteristics and building topology. It is shown that column axial shortening dominates the steel column stability. The hysteretic behaviour of HSS steel columns is further evaluated through corroborating finite element (FE) simulations. The steel column pre- and post-buckling behaviour is fully characterized depending on the type of steel material including the HYP400 steel. The FE results provide insight on the main differences of the lateral and axial damage progression between interior and end columns within the same steel MRF bay. The experimental data and corroborating finite element studies provide the basis for the development of a versatile steel column deterioration model that can explicitly simulate the axial-bending interaction, the column axial shortening due to local buckling induced softening and the cyclic deterioration in the column's strength and stiffness. Local buckling-induced softening is modeled through the development of an equivalent stress-strain formulation that includes a softening branch and can be fully characterized through conventional stub column tests. System level dynamic collapse simulation studies are conducted with over 80 archetype buildings with steel MRF systems ranging from 2 to 12-stories. Emphasis is placed on the importance of column axial shortening on the seismic performance of steel MRFs. It is shown that depending on the ground motion type, column axial shortening may result into slab tilting and catenary action prior to collapse. It is also shown that the use of the HYP400 steel columns can potentially enhance the collapse capacity of steel MRFs and reduce the expected residual lateral and vertical deformations in the aftermath of earthquakes." --

Author: Vitiea Noeun
Publisher:
ISBN: 9781267675965
Category :
Languages : en
Pages : 156

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This research focuses on safety assessment of steel special moment-resisting frames (SMFs). Moment-resisting frames are one common type of lateral load-resisting systems that have been used in steel buildings for almost 5 decades. After the 1994 Northridge earthquake, the reduced beam section (RBS) connection was introduced and widely recognized as one of the prequalified beam-to-column connections for use in a structural steel special moment-resisting frame. In this study, W14 and W24 column sections were used in the moment-resisting frame designs with the RBS connection to further compare their seismic performances. Moreover, the deflection amplification factors, Cd = 5.5 and Cd = 8, were also utilized in the designs of the special SMF. Briefly, a total of 12 special SMF structures were developed, and were divided into 3 groups: 5-story, 10-story, and 15-story. Each group contained 4 structures, such that two designs of W14 and W24 columns where Cd equaled 5.5 and another two designs of the same column depths where Cd equaled 8. The nonlinear analyses, nonlinear static and nonlinear dynamic analysis, were later implemented to assess the collapse performance of these 12 archetypes. The nonlinear static analysis was used to determine system overstrength and ductility, and the nonlinear dynamic analysis was performed to obtain median collapse intensity and collapse margin ratio of archetypes. Finally, an appropriate Cd factor was determined according to the height of archetype, and the comparison of seismic performances of W24 and W14 column sections was evaluated.