Civil Engineering ETDs

Publication Date

Spring 4-29-1972

Abstract

Prediction of the dynamic response of reinforced concrete beams by various analytical model techniques was considered. Four models were studied: (1) an elastic or elasto-plastic SDF model, (2) an SDF model based on experimental force-displacement data, (3) an SDF model based on a theoretical moment-flexural rigidity relationship, and (4) an MDF model based on a theoretical moment-flexural rigidity relationship.

Beam response, as predicted with the various models, was compared to experimental response data obtained from simply supported, singly reinforced, concrete beams. Static and dynamic response was considered. Dynamic model modifications for the stiffness, yield strength and damping were studied. Nominal model modifications considered were a dynamic stiffness factor of 1.0, a dynamic yield strength factor of 1.1, and 5 percent damping. For peak dynamic displacements less than ~ 2 times the static yield displacement, the SDF model based on static force­-displacement data modified by the nominal dynamic parameters were in good agreement with the experimental results. The order of agreement of the various model predictions and the experimental responses in this range was similar to that observed in comparing model static variations. The results indicated that the usual elastic or elasto-plastic formulation and the theoretical moment-flexural rigidity approach should be modified to more closely approximate static beam behavior. For peak dynamic responses approaching ~ 3.8 times the static yield displacement, the MDF model predictions exceeded the SDF model results and more closely approxi­mated the experimental data. Consideration of off-center displacements and beam accelerations indicated that the MDF model approach may be used successfully as a general analysis technique for reinforced concrete beams.

Document Type

Dissertation

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Committee Member (Chair)

Cornie Leonard Holsbos

Second Committee Member

John Lawson Brown

Third Committee Member

Eugene Milton Zwoyer

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