An Investigation of the Interaction of Reinforced Concrete Frames With Masonry Filler Walls
01 Nov 1970-
TL;DR: In this article, the beneficial effects on frame stiffness and strength which result from providing in-filled masonry walls in all frame openings are investigated, including load-deflection relationships, load-reinforcement strain curves, loadwall strain data, and information on cracking in both the wall elements and frame elements.
Abstract: : The beneficial effects on frame stiffness and strength which result from providing in-filled masonry walls in all frame openings are investigated. Tests to failure were conducted on eight one-story, one-bay frames; 13 five-story, one-bay frames; and six two-story, three-bay reinforced concrete frames. The test results are presented, including load-deflection relationships, load-reinforcement strain curves, load-wall strain data, and information on cracking in both the wall elements and frame elements. Analyses are presented enabling the calculation of the response of the framewall systems to horizontal loadings. The response to loads smaller than those cracking can be approximated as that of a cantilever beam, and the post cracking behavior approximates the response of a frame with knee braces. The forces causing diagonal cracking and failure in the wall elements were related to the results of tests of masonry specimens. The masonry walls led to an order of magnitude increase in stiffness and a significant increase in strength over unfilled frames, but the ductility was reduced. (Author)
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TL;DR: In this paper, the behavior of a type of building popular in high seismic zones with a lateral load-resisting system consisting of masonry-infilled reinforced concrete (RC) frames was investigated.
Abstract: This paper presents research on the behavior of a type of building popular in high seismic zones with a lateral-load-resisting system consisting of masonry-infilled reinforced concrete (RC) frames. Older buildings of this type typically were designed for gravity loads in combination with insufficient or no lateral loads, therefore they do not meet current seismic code requirements. Also, the participation of infill panels in the lateral load resistance of RC frames was not recognized in the original design, often resulting in an overly conservative design. In an attempt to determine the seismic vulnerability of this type of structure, an experimental program was carried out to evaluate the behavior of five half-scale, single-story laboratory models with different numbers of bays. The results indicated that infilled RC frames exhibit significantly higher ultimate strength, residual strength, and initial stiffness than bare frames without compromising any ductility in the load-deflection response. Furthermore, the number of bays appears to be influential with respect to the peak and residual capacity, the failure mode, and the shear stress distribution.
399 citations
TL;DR: In this article, a thorough overview of the different micromodels proposed for the analysis of infilled frames is presented, and the advantages and disadvantages of each micro-model are pointed out.
192 citations
Cites background from "An Investigation of the Interaction..."
...Many subsequent studies [75,102,27,190,165,133,28,4,5] have characterized in general the action of masonry infill walls as that...
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TL;DR: In this paper, the influence of masonry infills with openings on the seismic performance of reinforced concrete (R/C) frames that were designed in accordance with modern codes provisions is investigated.
Abstract: The influence of masonry infills with openings on the seismic performance of reinforced concrete (R/C) frames that were designed in accordance with modern codes provisions is investigated. Two types of masonry infills were considered that had different compressive strength but almost identical shear strength. Infills were designed so that the lateral cracking load of the solid infill is less than the available column shear resistance. Seven 1/3 – scale, single–story, single–bay frame specimens were tested under cyclic horizontal loading up to a drift level of 40%. The parameters investigated are the opening shape and the infill compressive strength. The assessment of the behavior of the frames is presented in terms of failure modes, strength, stiffness, ductility, energy dissipation capacity, and degradation from cycling. The experimental results indicate that infills with openings can significantly improve the performance of RC frames. Further, as expected, specimens with strong infills exhibited better ...
174 citations
TL;DR: In this article, the double-strut nonlinear cyclic model for masonry panels is used to predict the cyclic/seismic response of multi-storey infilled reinforced concrete frames.
Abstract: The effect of infill panels on the response of RC frames subjected to seismic action is widely recognised and has been subject of numerous experimental investigations, while several attempts to model it analytically have been reported. In this work, the implementation, within a fibre-based Finite Elements program, of a double-strut nonlinear cyclic model for unreinforced masonry panels is carried out. The adequacy of the model in predicting the cyclic/seismic response of multi-storey infilled reinforced concrete frames is then verified through comparisons against experimental results.
127 citations
TL;DR: In this paper, the authors presented the shake table tests of a 2/3-scale, three-story, two-bay, reinforced concrete frame infilled with unreinforced masonry walls.
Abstract: SUMMARY
This paper presents the shake-table tests of a 2/3-scale, three-story, two-bay, reinforced concrete frame infilled with unreinforced masonry walls. The specimen is representative of the construction practice in California in the 1920s. The reinforced concrete frame had nonductile reinforcement details and it was infilled with solid masonry walls in one bay and infill walls with window openings in the other bay. The structure was subjected to a sequence of dynamic tests including white-noise base excitations and 14 scaled historical earthquake ground motion records of increasing intensity. The performance of the structure was satisfactory considering the seismic loads it was subjected to. The paper summarizes the design of the specimen and the major findings from the shake-table tests, including the dynamic response, the load resistance, the evolution of damage, and the final failure mechanism. Copyright © 2011 John Wiley & Sons, Ltd.
125 citations
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01 Aug 1961
385 citations
"An Investigation of the Interaction..." refers background in this paper
...(12) Transverse reinforcement in the columns of the frame would increase the ductility and,in some cases, the strength of the system....
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TL;DR: In this paper, the stiffness of single and multistory frames is estimated by assuming equivalent diagonal strut to replace infill; effective width for equivalent strut is derived theoretically and checked by model experiments.
Abstract: Methods for predicting approximate lateral stiffness of single and multistory frames; stiffness of frames is considered by assuming equivalent diagonal strut to replace infill; effective width for equivalent strut is derived theoretically and checked by model experiments.
283 citations
TL;DR: In this article, the authors investigated the behavior of diagonally-loaded square infilled frames and developed approximate theoretical analyses based on the length of contact between the frame and infill to predict the diagonal stiffness and strength of the structure.
Abstract: An investigation of the behavior of diagonally-loaded square infilled frames is described first. Series of experiments on diagonally-loaded models with a range of frame stiffnesses indicated that a small increase in frame stiffness has a magnified effect on the over-all stiffness and strength of the structure. Approximate theoretical analyses, based on the length of contact between the frame and infill, are developed to explain this composite behavior, and to provide methods of predicting the over-all diagonal stiffness and strength. The behavior of laterally-loaded infilled frames is considered next. The methods proposed for the diagonally-loaded case are adapted to predict the lateral stiffness and strength of single or multi-story square infilled frames. The results of experiments on single and double-story models support the pro-posed methods of prediction.
264 citations