INSTRUMENTATION, TESTING, AND MONITORING OF A NEWLY CONSTRUCTED REINFORCED CONCRETE DECK-ON-STEEL GIRDER BRIDGE - PHASES I AND II

The research project aimed at exploring, in two phases, the issues and advancement of the state-of-knowledge in instrumented monitoring of bridges. The first phase necessitated a rigorous investigation of commercially available hardware for bridge monitoring in terms of cost, laboratory verification, field accuracy, and useful lifetime. In the second phase, the initial design of a monitoring system for a typical three-span steel-stringer bridge was followed by the installation of the scaffolding and wireway framework, 54 selected high-speed and long-term transducers on steel girders, a weather station, and a computer-controlled data acquisition and processing station on a recently constructed bridge in Cincinnati (#HAM-42-0992). One of the approaches in nondestructive bridge testing is the use of diagnostic load testing and instrumented health monitoring. Such techniques can provide quantitative, comprehensive, and damage sensitive information about the bridge. Instrumentation that is placed on the structure is composed of static (strain gages, displacement gages, tiltmeters, thermocouples, pressure transducers) and dynamic sensors (accelerometers, velocity transducers). The test duration can vary from a couple of seconds (crawl-speed truck loading, traffic monitoring), to years of continuous monitoring. The loading can be a simple known pattern of loaded trucks, environmental loading (e.g., wind, temperature), traffic, earthquake, etc. Using this technique with extensive instrumentation, it is possible to measure all the critical aspects of bridge response and calibrate comprehensive finite-element analytical models that accurately simulate the global behavior as well as the localized forces and distortions of a test bridge. This project also allowed the authors to explore a number of less known mechanisms related to the actual behavior and performance of steel stringer bridges (e.g., integral abutments).