Field test of an intelligent stiffener for bridges at the I-35 Walnut Creek Bridge

The addition of controllable hardware to structures to mitigate vibration t hat results from dynamic loads is an emerging area of technological develop ment. The paper describes the results of a research project that was conduc ted to test a relatively new approach to structural control: an adjustable semi-active hydraulic actuation system that was attached to an in service i nterstate bridge. The system, which is powered by a 12-volt automative batt ery, has been tested over a 2-year period. Data indicates that the system r educes truck induced peak stresses by over 50 per cent, and calculations, p er NCHRP 299, indicate that the safe life of the structure is increased by approximately 50 yr. The installed cost of the system represents less than 10 per cent of the cost to replace the bridge. Copyright (C) 1999 John Wile y & Sons, Ltd.