Evaluation of the seismic performance of reinforced concrete buildings.

摘要

The building codes in various jurisdictions, including Canada, follow a common concept in designing buildings to achieve an acceptable seismic performance. The objective underlying the concept is to ensure that the buildings designed based on code provisions should be able to resist minor earthquakes without damage, resist moderate earthquakes with some non-structural damage, and resist major earthquakes without collapse, but with some structural as well as non-structural damage. Seismic provisions in the building codes have evolved over the years to achieve this goal. Existing building codes focus on the minimum lateral load for which a structure must be designed. However, it is also necessary to include the demand and response characteristics of a structure, in the design.; The National Building Code of Canada (NBCC) is currently undergoing a review. One of the aims of this review is to permit an explicit definition of the expected seismic performance of buildings designed according to the code. The committee in charge of preparing the recommendations for seismic provisions of NBCC is considering a suggestion by which the calculation of the design lateral forces will be carried out on the basis of new seismic hazard maps of Canada. The new hazard maps, prepared by the Geological Survey of Canada (GSC), are based on the response spectral ordinates, rather than on the peak ground velocity or peak ground acceleration. It is expected that the future version of NBCC will require a building to be designed on the basis of these spectra, which are called, the uniform hazard spectra (UHS).; It is generally expected that if a structure designed on the basis of the seismic provisions of the building code is detailed properly to prevent the premature brittle failure modes, and a capacity design principle is followed by which columns are made stronger than the beams to prevent storey sway mechanism, the structure would meet the performance objectives during expected levels of earthquakes. However, adequate studies are necessary to corroborate this idea.; The main objectives of the current research is to study the seismic performance of buildings designed according to the new seismic provisions (i.e., based on the UHS based design forces). A review of the literature shows that there are not enough reports on studies on seismic performance of buildings designed according to NBCC seismic provisions. In this thesis a plan for comprehensive study of seismic performance of such buildings is presented. The following types of structural forms are identified for investigation: (a) concrete moment resisting frames, and (b) concrete shear wall systems.; Static push-over analyses and nonlinear dynamic analyses are generally used to calculate the damage state in a structure. The seismic performance of a structure is determined on the basis of its damage state under an earthquake ground motion. A simplified procedure for seismic performance evaluation of buildings is also proposed.