NEHRP Clearinghouse

Methodology for Mitigation of Seismic Hazards in Existing Unreinforced Masonry Buildings, Phase 1.
Adham, S. A.; Ewing, R. D.
National Science Foundation, Washington, DC. Applied Science and Research Applications., March 1978, 93 p.
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A multiphased program is initiated to develop a methodology for the mitigation of seismic hazards in existing unreinforced masonry (URM) buildings. The present research, part of Phase 1, identifies trends in the seismic response of the components of URM buildings and determines what studies and testing are necessary to arrive at a methodology that can be used nationwide. The response of plywood, diagonal-sheathed, and straight-sheathed diaphragms, represented by lumped-mass mathematical models, was studied. Experimental data on static loading and unloading were used. Both local and distant earthquake ground motions were used as inputs. The results show a strong dependence of the diaphragm response on the long-period content of the input. The response of masonry walls subjected to in-plane earthquake ground motion was also studied. The analytical results show that the model used can reasonably predict the response of the wall as a function of its height-to-width ratio and of the stiffness of the supporting soil. The report evaluates methods for selecting earthquake ground-motion input at a site in the United States and describes analysis methods that can be used to determine the response of URM buildings to earthquake forces.
Masonry; Seismic design; Earthquake resistant structures; Reinforcing materials; Masonry walls; Seismic waves; Mathematical models; Earth movements; Walls; Dynamic response; Buildings; Earthquake engineering; Ground motion; Dynamic structural analysis