NEHRP Clearinghouse

Title
Flexible Sub-Surface Building-Foundation Interfaces for Aseismic Design (Preliminary Studies).
File
PB81243891.pdf
Author(s)
Raupach, E.; Schumacker, B.; Biggs, J. M.
Source
National Science Foundation, Washington, DC., April 1981, 138 p.
Identifying Number(s)
R81-8
Abstract
The feasibility of constructing buildings on horizontally flexible foundations to mitigate the effects of earthquakes is explored. The specific concept studied involves the use of slender steel piles enclosed in sleeves to permit flexural distortion. Piles are designed by a simple procedure using smoothed response spectra. The performance of the designed systems are then studied using time histories of actual ground motions. It is shown that the simple design procedure is adequate. Building-pile systems with periods up to 12 seconds are found to be physically feasible. This results in maximum building forces corresponding to seismic coefficients less than current code requirements even though the building remains elastic. The report includes descriptions of ground motions used in the study, pile design equations and procedures, and the time-history analysis.
Keywords
Dynamic response; Ground motion; Buildings; Earthquake engineering; Flexible foundations; Earthquake resistant structures; Lateral stability; Seismic design; Earthquakes; Structural design; Soil structure interactions; Pile foundations; Design criteria