Response of Low-Rise Frame Structures to Dynamic Soil Motions
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 beam/slab 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1990
- Accession Number
- ADA218332
Entities
People
- John E. Higgins Jr.
Organizations
- Air Force Institute of Technology