Second Generation In-Service Bridge Monitoring System

A second generation in-service Bridge Monitoring System (ISBMS)was recently developed by the authors. The system measures live load strains in a bridge due to site-specific traffic. This report documents the system hardware, software, laboratory tests and field tests of the ISBMS. The original ISBMS was developed in 1999. The system was designed to measure the peak strain in a bridge girder or slab due to heavy vehicles crossing the bridge. It was small, lightweight, battery powered, portable, and rapidly deployable. The first generation ISBMS was capable of operating, under attended, for up to three weeks. It proved to be a very useful tool for bridge diagnostics, but was limited by the following features: data could only be retrieved by physically connecting to the system with a laptop computer in the field; it was limited to capturing only peak strains and could not be reprogrammed; used a full bridge strain transducer and would not accept a quarter-bridge strain gage as input. Am effort was made to enhance the capabilities of the ISBMS, make it user-friendlier, and simplify the setup and operation of the system. The new second generation system would incorporate the following improvements: would be remotely accessible via wireless communication; would be accessed through a user friendly web site; would accept a quarter-bridge strain gage, as well as a full bridge strain transducer; would provide three different modes of data collection, and be programmable.