Field Demonstration of Non-Destructive Bridge Evaluation Using QuantitativeThermographic Stress Analysis

摘要

A field demonstration of nondestructive evaluation using thermography wasundertaken at an interstate highway bridge to assess the ability of this emerging technology to define the state of stress in geometrically complex regions of large structures undergoing random loading. Thermographic Stress Analysis (TSA), which uses infrared sensing to construct an image of surface stresses by measuring the small thermoelastic temperature changes at many positions over the surface of a region of interest, has previously been proven to be reliable, but only in laboratory situations for relatively small frames under constant-amplitude loading. The results obtained during the field demonstration revealed that quantitative stress analysis may be accomplished while relying solely on randomly applied, short-duration loads from trucks to produce the necessary changes in stress.