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Earthquake resistant structures

About: Earthquake resistant structures is a research topic. Over the lifetime, 1126 publications have been published within this topic receiving 27467 citations.


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Proceedings ArticleDOI
22 Apr 2019
TL;DR: In this paper, the authors developed practical repair strategies for ER CFST columns which exhibit this ductile failure progression, with the goal of reestablishing the original column strength and stiffness.
Abstract: Concrete filled steel tubes (CFSTs) provide a unique, economical alternative to traditional reinforced concrete (RC) columns in highway bridges for their ease of construction and efficient structural properties. The steel tube provides optimal flexural resistance and continuous confinement to the infill concrete, while the concrete fill improves stiffness and strength of the column, and prevents inward local tube buckling of the steel tube. Recent research has developed a practical and structurally robust, column-to-foundation/cap-beam connection for use in mid-to-high seismic regions. This connection, referred to as the embedded ring (ER) connection, is a full-strength connection, where well-detailed, ER CFST columns exhibit local, outward tube buckling directly above the foundation/cap-beam when subjected to reverse-cyclic, lateral loadings. This typical ductile failure mode is readily identifiable post-earthquake events, and is uniquely advantageous compared to typical RC columns due to limited concrete spalling and the availability of the steel tube for welded connections. The main objective of this research was to develop practical repair strategies for ER CFST columns which exhibit this ductile failure progression, with the goal of reestablishing the original column strength and stiffness. Two strategies were developed: (1) a traditional plastic hinge relocation method that utilizes an enlarged, CFST pedestal that surrounds the damaged region, and (2) a performance-based repair that implements external energy dissipators and column-rocking to limit damage. A non-linear, numerical analysis approach was adopted to assess the hysteretic response of these repair methods in comparison to that of an undamaged, CFST column. Results indicated that both repair strategies successfully restored lost stiffness and strength, specifically peak strength values of 1.26Mp and 1.02Mp for the traditional and performance-based methods were observed, respectively, where Mp represents the plastic moment of the original column. Additionally, a limited experimental study was carried out on the proposed, bucking restrained, energy dissipator where, under cyclic-compressive loadings, compressive yielding (1.12Fy) and inelastic strains (9.0ey) were measured within the laterally-restrained, structural fuse of the dissipator.

3 citations

Proceedings ArticleDOI
07 Dec 2009
TL;DR: The International Building Code [ICC, 2006], and the attendant structural design standard ASCE/SEI 7-05 Minimum Design Loads for Building's and Other Structures [ASCE, 2006] provide the structural criteria for buildings, as well as the seismic design requirements for nonstructural components, equipment, and systems as discussed by the authors.
Abstract: The International Building Code [ICC, 2006], and the attendant structural design standard ASCE/SEI 7-05 Minimum Design Loads for Building's and Other Structures [ASCE, 2006] provides the structural criteria for buildings, as well as the seismic design requirements for nonstructural components, equipment, and systems. Over the years this criteria has been expanded from essentially nominal design requirements (2 pages) to an entire chapter of content dedicated to nonstructural components in ASCE 7-05, not including additional referenced industry standards for certain components. With this additional design complexity, are we really sure that we will achieve the expected earthquake performance intended for nonstructural components, equipment, and systems, or are there other issues affecting desired performance that require greater attention? This paper will present issues that compromise achieving the expected nonstructural component earthquake performance that the codes and standards intend by examining several case examples of projects in the Midwest. Specifically, four (4) construction projects will be examined where enhanced seismic performance and standard code compliance performance levels were used for design of the building structure and nonstructural components. The paper will present the issues affecting the seismic performance of nonstructural components from initial design, development of contractor implemented seismic design performance criteria, contract language, contractor seismic design implementation, contractor construction, and monitoring construction quality. As the paper will conclude, achieving enhanced earthquake performance for nonstructural components, equipment, and systems is difficult, but not impossible. Suggested solutions are offered for improved earthquake performance of nonstructural components on future projects.

3 citations

Journal ArticleDOI
TL;DR: In this article, a nonlinear time history analysis using step-by-step integration is used to trace the dynamic response of a structure during the entire vibration period and is able to accommodate the pulsing wave form.
Abstract: Strong near-fault ground motion, usually caused by the fault-rupture and characterized by a pulse-like velocity-wave form, often causes dramatic instantaneous seismic energy (Jadhav and Jangid 2006). Some reinforced concrete (RC) bridge columns, even those built according to ductile design principles, were damaged in the 1999 Chi-Chi earthquake. Thus, it is very important to evaluate the seismic response of a RC bridge column to improve its seismic design and prevent future damage. Nonlinear time history analysis using step-by-step integration is capable of tracing the dynamic response of a structure during the entire vibration period and is able to accommodate the pulsing wave form. However, the accuracy of the numerical results is very sensitive to the modeling of the nonlinear load-deformation relationship of the structural member. FEMA 273 and ATC-40 provide the modeling parameters for structural nonlinear analyses of RC beams and RC columns. They use three parameters to define the plastic rotation angles and a residual strength ratio to describe the nonlinear load-deformation relationship of an RC member. Structural nonlinear analyses are performed based on these parameters. This method provides a convenient way to obtain the nonlinear seismic responses of RC structures. However, the accuracy of the numerical solutions might be further improved. For this purpose, results from a previous study on modeling of the static pushover analyses for RC bridge columns (Sung et al. 2005) is adopted for the nonlinear time history analysis presented herein to evaluate the structural responses excited by a near-fault ground motion. To ensure the reliability of this approach, the numerical results were compared to experimental results. The results confirm that the proposed approach is valid.

3 citations

Journal Article
TL;DR: In this article, a method is described for calculating the probability of failure of reinforced concrete frame structures due to earthquake loading, for use in code calibration exercises, where failure criterion is taken to be maximum inter-storey displacement.
Abstract: A method is described for calculating the probability of failure of reinforced concrete frame structures due to earthquake loading, for use in code calibration exercises. The failure criterion is taken to be maximum interstorey displacement. This is related to basic structural variables through the medium of the cumulative inelastic energy or damage energy for each storey, computed by first finding the total damage energy for a structure through the use of single degree of freedom inelastic analyses, and then by determining the fraction of energy in each storey by an elastic random vibration analysis. The procedure is checked against the results of full time history analyses and is found to give satisfactory results.

3 citations

Proceedings ArticleDOI
10 Oct 2007
TL;DR: In this paper, a 3-bay RC frame composed of shear-critical columns and ductile columns to allow for load redistribution was used to predict hysteretic backbone until the point of structural collapse with satisfaction.
Abstract: Collapse experiments are found very helpful in facilitating collapse analysis of new buildings and identification of older buildings that are at high risk of structural collapse during severe earthquake events. Experimental observations from dynamic global collapse of a single story 3-bay RC frame are presented in this paper. The frame is composed of shear-critical columns and ductile columns to allow for load redistribution. A near-fault record from the September 21 (local time) 1999 Chi-Chi Taiwan earthquake was employed. Preliminary investigation shows that existing empirical equations are able to predict hysteretic backbone until the point of structural collapse with satisfaction.

3 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232
20223
202113
20209
201916
201813