In-Situ Load Testing of Bridge A6101 Lexington, MO

摘要

The scope of this project is the evaluation of a high performance steel bridge located in Lexington, Missouri. The bridge number is A6101 and it is located on Mo. Rt. 224/Mo. Rt. 13. To evaluate the load-carrying capacity of the bridge, a nondestructive field test was conducted. The bridge was tested both statically and dynamically using six H20-44 trucks as specified in AASHTO (2002). The dynamic load was applied by moving the trucks at different speeds over the bridge deck. The bridge deflection under static load was measured using a robotic tacheometry (total station) system (RTS) that offers a non-contact deflection measurement technique. RTS has the capability to measure the spatial coordinates of discrete points on a bridge in three dimensions without having to touch the structure. In this project, both RTS and conventional extensometers (LVDTs) were used to measure the bridge deflections. The RTS was used to monitor the deflection of 19 points located on the bridge girders. The LVDTs were primarily used to measure the dynamic deflection of the bridge; they were mounted in correspondence to three prisms monitored by the total station in order to validate the accuracy of the latter during the static test. The comparison between the theoretical results according to the AASHTO standard specifications and experimental data, and between static and dynamic loads allowed establishment of the safety of the structure. A finite element method analysis was undertaken. The numerical model was able to represent the behavior of the bridge and therefore could be used to determine its load rating.