The Earthquake Engineering Online Archive

Infilled frames in earthquake-resistant construction

Klingner, Richard E.; Bertero, Vitelmo V.

UCB/EERC-76/32, Earthquake Engineering Research Center, University of California, Berkeley, 1976-12, 291 pages (530/K57/1976)

The effects of masonry infill panels on the seismic hysteretic behavior of reinforced concrete frames are investigated experimentally and analytically. The experimental phase consists of quasi-static cyclic load tests on a series of one-third-scale model subassemblages of the lower three stories of an eleven-story, three-bay frame with infills in the two outer bays. Emphasis is placed on simulating the proper force and displacement boundary conditions. The infilled frames are designed and constructed in accordance with the following guidelines: (1) frame members (particularly the columns) are designed for high rotational ductility and resistance to degradation under reversed cyclic shear loads; (2) gradual panel degradation is achieved by using closely spaced infill reinforcement; and (3) panel thickness is limited so that the infill cracking load is less than the available column shear resistance. The infilled frames are found to offer many advantages over comparable bare frames, particularly with respect to their performance under strong ground motions. The analytical phase consists of developing relatively simple, macroscopic mathematical models for predicting the experimentally observed bare and infilled frame behavior. In particular, the infilled frame model is found to give excellent predictions of the observed response. It is concluded that the procedure used can be applied to the analysis of large infilled frame structures. The aseismic design implications of these results are discussed, and areas for further investigation are recommended.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-76-32.pdf (11 MB)