Research On Safety Evaluation Of Existing Bridge Based On Load Test

In recent decades, with the progress of science and technology, the development of bridge structures has made remarkable achievements, and bridge experimental researches have played an important role both in promoting and developing the theory of bridge structure design and calculation, and solving problems in production practices. A large number of existing bridges need to be tested whether its bearing capacity and structural characteristics meet the design criteria and operational requirements by load test, to ensure their normal use. Based on the load tests and theoretical calculations of Binhu bridge in E Zhou City, a related research is carried out in this paper.Mastering the bridge load test method is a prerequisite for successful trials. In this paper, the bridge static and dynamic load test methods have been conducted in-depth research. Concerning the static test program, the static load test method made a more detailed presentation, including test object selection, load condition design, principles of measuring-point arrangement, the selection and establishment of test loads and loading methods, and descriptions on the test data processing and evaluation index; in the dynamic load test method, at first,the conventional dynamic tests of bridge projects are introduced, then the most commonly used loading methods of the actual bridge dynamic test are given, at last dynamic characteristics and the evaluation indexes of the bridge are introduced and summarized.According to the requirements of the bridge test content, the surface detection of the bridge and the static and dynamic tests are executed to comprehensively evaluate whether the structure safety bearing capacity can meet the design standards and requirements. In order to testing whether there are damages, cracks, deformations, seepages, exposed reinforcement corrosion and blockage of water in every components, the surface test made a detailed inspection, mapping out their exact location and extent, and the linear and elevation of the structures are also measured.According to the characteristics of the continuous rigid-frame bridge, the study developed a detailed static and dynamic load test program. In the static load test, it obtains the maximum strain and deflection of each control sections, and measures the strain of the maximum negative moment control section near the pier top beam of the rigid frame Piers. Using the finite element software MIDAS to model on the test of bridge calculation and analysis and make assessment of the actual bearing capacity of the whole bridge compared with the actual experiment data analysis. In the dynamic load test, the bridge structure were collected in the different pulse, the speed bump and different conditions of the dynamic response signals, and calculated the natural vibration frequency, damping ratio and the impact factor under the various speeds.The bridge static and dynamic load test results show that the overall structure of this bridge is basically intact, and its safety performance can meet the requirements. The surface test results show that the bridge deck pavement wears relatively serious, and there are many cracks in the structure and the expansion joints have been basically destroyed. All these factors have affected the safety and durability of the structure, more over, these problems must be solved as soon as possible. The research achievements of this article provide a guidance opinion for reinforcing the maintenance of the bridges and have great reference value for the detection of similar bridges.