Estimation of Live Load Distribution Factor for a PSC I Girder Bridge in an Ambient Vibration Test

Abstract

Maintenance of bridges in use is essential and measuring the live load distribution factor (LLDF) of a bridge to examine bridge integrity and safety is important. A vehicle loading test has been used to measure the LLDF of a bridge. To carry this out on a bridge in use, traffic control is required because loading must be performed at designated positions using vehicles whose details are known. This makes it difficult to measure LLDF. This study proposed a method of estimating the LLDF of a bridge using the vertical displacement response caused by traveling vehicles under ambient vibration conditions in the absence of vehicle control. Since the displacement response measured from a bridge included both static and dynamic components, the static component required for the estimation of LLDF was extracted using empirical mode decomposition (EMD). The vehicle loading and ambient vibration tests were conducted to verify the validity of the proposed method. It was confirmed that the proposed method can effectively estimate the LLDF of a bridge if the vehicle type and driving lane on the bridge are identified in the ambient vibration test.

Vehicle Load Estimation Using the Reaction Force of a Vertical Displacement Sensor Based on Fiber Bragg Grating

“…If the influence line value is expressed as Equation ( 16) and the reaction force is expressed as Equation (17), while Equation ( 15) can be expressed as Equation (18).…”

“…Among the load factors that may occur on a highway bridge over the long term, vehicle load is the most important factor, in addition to the temperature load and concrete creep. A bridge can, therefore, only be efficiently maintained if the vehicle loads it is subjected to are clearly identified [15][16][17].…”