Browsing by Subject "Seismic behavior"

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Design provisions for autoclaved aerated concrete (AAC) infilled steel moment frames
(2009-12) Ravichandran, Shiv Shanker; Klingner, R. E.
In this dissertation, the seismic behavior and design of AAC-infilled steel moment frames are investigated systematically. The fundamental vehicle for this investigation is the ATC-63 methodology, which is intended for the establishment of seismic design factors for structural systems. The ATC-63 methodology is briefly reviewed, including the concepts of archetypical structures, design rules and mathematical models simulating the behavior of those archetypes. A limited experimental investigation on the hysteretic behavior of an AAC-infilled steel moment frame is developed, conducted, and discussed. Using the experimental results of that investigation, the draft infill design provisions of the Masonry Standards Joint Committee (MSJC) are extended to AAC infills, and a mathematical model is developed and calibrated to simulate the behavior of AAC infills under reversed cyclic loads. Prior to application of ATC-63 methodology to AAC-infilled steel moment frames, the methodology is applied to an example steel moment frame to demonstrate the methodology and verify understanding of it. Then, archetypical infilled frames to be evaluated by the ATC-63 methodology are developed using a series of pushover analyses. Infill configurations whose total lateral strength in a particular story exceeds about 35% of the lateral strength of the bare frame in that story are observed to provoke story mechanisms in the frame. Based on this observation, archetypical infilled frames are selected conforming to two infill configurations: uniformly infilled frames, and open ground story frames. Each infill configuration includes archetypes whose ratio of infill strength to bare-frame strength at each story is less than 35%, and archetypes whose ratio is greater than 35%. The former archetype is typical of steel moment frames infilled with AAC; the latter archetype is typical of steel moment frames infilled with conventional (clay or concrete) masonry. The ATC-63 methodology, specialized for application to infilled frames, is applied to the archetypical infilled frames developed above. The performance of those archetypical infilled frames is evaluated, and seismic design factors are proposed for AAC-infilled steel moment frames. The extension of this work to other types of infilled frames is discussed.
Displacement-based seismic design and tools for reinforced masonry shear-wall structures
(2012-12) Ahmadi Koutalan, Farhad; Klingner, R. E.; Jirsa, James O.; Wood, Sharon; Yura, Joseph A.; Kyriakides, Stelios
The research described here is part of a multi-university project on “Performance-based Seismic Design Methods and Tools for Reinforced Masonry Shear-Wall Structures.” Within the context of that project, the objective of the research described in this dissertation was to develop and validate a specific displacement-based seismic design methodology for masonry structures. Experimental work consisted of reversed cyclic loading tests of reinforced masonry wall segments with different boundary conditions, aspect ratios, axial loads, and reinforcement detailing. Analytical work consisted of developing analytical models for in-plane concrete masonry shear wall segments; calibrating those models using reversed cyclic test data; and using those models to successfully predict the nonlinear seismic response of two full-scale, multi-story reinforced masonry specimens tested on the shake-table at the University of California at San Diego. Design work consisted of the force-based and displacement based design of those specimens. Based on the results, provisions for displacement-based seismic design are proposed for inclusion in United States design codes.
Seismic behavior and design of low-rise reinforced concrete masonry with clay masonry veneer
(2010-05) Jo, Seongwoo; Klingner, R. E.; Hughes, Thomas J.; Jirsa, James O.; Kallivokas, Loukas F.; Wheat, Dan L.
The research described here is part of a multi-university project on “Performance-based Design of New Masonry Structures.” Within the context of that project, the main objectives of this research was to study the inelastic seismic performance of low-rise concrete masonry structures with clay masonry veneer and veneer connectors; to develop analytical models for those structures and the elements comprising them; and to use the results of the research to propose refinements to current design provisions for concrete masonry with clay masonry veneer. The experimental work described here includes the design and testing of concrete masonry wall specimens with clay masonry veneer under quasi-static loading. Identical specimens were subjected to shake-table testing at another university. The experimental work described here also includes the design of a full-scale, one-story concrete masonry building specimen with clay masonry veneer. That building specimen was subjected to shake-table testing at another university. The analytical work of this research includes the development of nonlinear hysteretic models for concrete masonry walls, clay masonry veneer and veneer connectors. The analytical models for wall specimens were calibrated using the results of the quasi-static and shake-table tests of wall specimens. The analytical model for the building specimen was compared with and refined using shake-table test results for the building specimen. Finally, the calibrated and refined analytical model of the building specimen was used for parameter studies intended to supply general information about the behavior of low-rise reinforced concrete masonry structures with clay masonry veneer. Based on the these experimental and analytical results, basic concepts of the seismic response and design of low-rise concrete masonry buildings were reaffirmed; most design and construction requirements of the 2008 MSJC Code and Specification were reaffirmed; and several recommendations were made to improve those requirements.