Application of probabilistic tools to extend load test design of bridges prior to opening

摘要

Load tests of bridges are widely performed in a large number of countries. Deterministic comparison of measurement results to the theoretical, FEM (finite element method)-based outcomes with possible further calibration is mostly applied. Sometimes, the data collected in the tests are also used to calibrate the reliability factors of bridge structures or their components. This work proposes to complement the stage of the load test design with the use of probabilistic tools. This approach is intended to provide a reliable and trustworthy limit range of measured values (e.g. displacements) instead of restrictive single values, streamlining the performance of in-situ tests. The proposed procedure is supported by an arch bridge example with the following uncertainty sources: random imperfections of the arch girder, random stiffness of the deck and random total weight of the applied load trucks. The presented calculations refer to global structural stiffness assessment. Both point estimate method (PEM) and response surface method (RSM) are applied here. It has been shown that the proposed procedure effectively supplements the deterministic approach, thus the suggested extension of application of probabilistic tools to bridge load test design is innovative and justified.