The Earthquake Engineering Online Archive

Simplified methods of analysis for earthquake resistant design of buildings

Cruz, Ernesto F.; Chopra, Anil K.

UCB/EERC-85/01, Earthquake Engineering Research Center, University of California, Berkeley, 1985-02, 250 pages (620/C78/1985)

In Part I of this report, the accuracy is evaluated of the response spectrum analysis (RSA) for estimating the maximum response of a building directly from the earthquake design spectrum in order to develop better simplified analysis procedures suitable for preliminary design of buildings and for inclusion in building codes. In Part II, a simplified RSA procedure (SRSA) is given for cases where a building's seismic response can be estimated by considering only the first two vibration modes in the RSA procedure. Results for the SRSA and RSA procedures are compared. A hierarchy of four analysis procedures for determining earthquake forces for purposes of building design is established: code-type procedure, SRSA, RSA, and response history analysis (RHA). Criteria are presented which can be used to evaluate the results from each procedure and to decide whether it is necessary to improve results by proceeding to the next procedure in the hierarchy. In Part III, formulas for base shear, height-wise distribution of lateral forces, and computation of overturning moments as specified in the Uniform Building Code, Mexico's Federal District Building Code, and ATC-3 design provisions are evaluated based on dynamic analysis results. It is demonstrated that these formulas do not properly recognize the effects of building parameters controlling the significance of higher mode contributions in the response. An improved procedure which recognizes these parameters is developed to compute earthquake forces for preliminary building design.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-85-01.pdf (17 MB)