Accession Number:

ADA218332

Title:

Response of Low-Rise Frame Structures to Dynamic Soil Motions

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1990-05-01

Pagination or Media Count:

273.0

Abstract:

The major objective of this thesis was to develop a simplified model to simulate the response of low-rise structures subjected to dynamic loads. The model incorporates the influence of soil and floor flexibility and is based upon underlying assumptions of static portal frame analysis. The study was extended to incorporate mono-symmetric structures with and without setback subject to self-induced torsion, as well as asymmetric frames. This model provides estimates of any desire force or displacement which might be determined in a corresponding space frame model. For selected design parameters, including maximum base shear and torque, maximum horizontal roof deflection, and maximum beam forces shear, moment, and torque, the average errors for all comparisons to space frame calculations were less than 10. Prior to development of the simplified model, preliminary studies assessed the impact of linear soil- structure interaction effects SSI upon the response of space frames with flexible mat foundations and composite beamslab floor systems. An extensive parameter study of representative space frames was conducted, in which response of the frames supported on a modest soil volume of finite elements was used to determine an effective distribution of equivalent soil springs. With the equivalent soil spring distribution in place, each frame was then subjected to one or more earthquake loads using modal analysis and appropriate mode combination techniques. Within the limits of linear analysis of uniformly applied horizontal soil leads, mat flexibility is significant only to the response of the mat foundation of the structure.

Subject Categories:

  • Soil Mechanics
  • Structural Engineering and Building Technology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE