Date of Award

1-1-2010

Document Type

Campus Access Dissertation

Department

Civil and Environmental Engineering

Sub-Department

Civil Engineering

First Advisor

Paul Ziehl

Abstract

This investigation is focused on the performance and validation of the 24h load test method (24h LT), the cyclic load test method (CLT), and acoustic emission (AE) techniques when used on self-compacting prestressed lightweight and normal weight concrete girders. The current investigation examines data obtained from the four point loading tests of six full scale T-girders, and applies the current criteria from these methodologies to evaluate the presence of damage and structural integrity. Experimental results indicate that the 24h load test method was insensitive to the presence of damage in prestressed concrete girders and hence did provide a satisfactory integrity assessment of the members. Also, permanency, repeatability, permanency ratio, and residual displacement criteria in the CLT were insensitive to damage for the girders included in the study.

The global integrity parameter (GIP) which takes into account specific mechanical features of the member is proposed for quantitative assessment of the level of damage in prestressed concrete girders and results indicate good correlation with the experimental data.

Results from the Calm ratio vs. Load ratio analysis (CR vs. LR) using cumulative energy for the computation of both variables, show good correlation with the amount of damage experimentally identified in the members and higher sensitivity for damage detection at relatively low levels of load. Additionally, the arch of damage is proposed as a quantifiable parameter from the CR vs. LR analysis along with an alternative formulation of the GIP, which can be effectively used to trigger damage detection during load testing.

Rights

© 2010, Francisco Alejandro Barrios Illidge

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