Proof Load Testing of Highway Bridges

Abstract

It is estimated that there are more than half a million highway bridges in the United States. Many of these bridges have deteriorated considerably because of age and inadequate maintenance and inspections, whereas the average daily truck traffic and truck loads have increased. Careful evaluation is required to make rational economic and safety decisions concerning the rehabilitation of each bridge. Proof load testing is an efficient tool that can be used to evaluate the performance of existing bridges. The objective of the study was to ensure the safety of two highway bridges located in Michigan by proof load testing. For the first bridge the design details were not available, and the second bridge had heavy corrosion in the lower flanges of its steel girders. Usually, the proof load level is about twice the maximum allowable load. Allowable loads in Michigan are considerably higher than those in other states. Therefore, military tanks on flatbed trailers were used to achieve the high target proof load levels. These tanks were provided by the Michigan National Guard. Load was increased in several steps, and the strains and deflections in the girders were measured. No sign of distress was observed during the tests. The capacity of each bridge was found to be significantly higher than the analytical capacity.

Proof load testing of reinforced concrete slab bridges in the Netherlands

“…Proof loading 14,15 can be carried out on existing bridges. If a certain load can be carried, sufficient capacity is proven.…”

Bridge Instrumentation and Monitoring for Structural Diagnostics

“…The reliability of bridge management systems depend on the successful integration of nondestructive testing and evaluation methods [29][30][31][32]. It has been observed from a bridge's response to the same load input over several months that the natural vibration frequency and flexibility coefficients may change as much as 10-15%, while local strain and global deflection responses may vary in the order of 5% [7].…”

Characterizing the Importance of Porosity of Large Woody Debris Accumulations at Single Bridge Piers on Localized Scour

“…Most studies focused on impervious LWD jams; these studies potentially overestimated the effects of LWD on scour, since Parola et al. (2000) showed that porosity can have a great importance on the drag force applied to LWD at bridge piers. Pagliara and Carnacina (2010) tested scour at single bridge piers with LWD using two values of porosity (namely 0 and 0.6) and found that temporal evolution was similar across experimental tests.…”