Health State Evaluation for Multi-Span Double-Curvature Arch Bridge Based on Static-Dynamic Load Testing

Abstract

The method and process of health state evaluation for a five-span double-curvature arch bridge across Lei River in Hunan provincial highway S316 in China were introduced. Some tests performed on the bridge, namely, appearance quality inspection, ambient vibration test, bridge-vehicle dynamic interaction test, and static load test for 2 spans with 4 different load cases. The main tested items included bridge deck deflection, strain of main arch ribs, lateral load distribution factor, bridge dynamic deflection, and structural vibration acceleration and so on. The self-vibration frequencies of tested spans were calculated using model analysis method. Results from both of test and analysis show that: structural stiffness of the first span basically meet the design requirements, but its bearing capacity and security reserve lower than that of design value. Structural stiffness especially lateral stiffness of the forth span was much less than their design value. Based on the results from static load test and assessment standards for technology state of bridge, the health state of this bridge was assessed and corresponding maintenance and strengthening projects were proposed. INTRUCTION With the rapid development of China's economic construction, traffic flow and traffic load intensity of highway rapidly grow, and the over loading phenomenon of highway has become increasingly common, in additional a lot of bridges had served for a long time, the problem of bridge disease and damage has being increasingly prominent. In 2000, a census was performed for 187 thousand bridges in Guangdong Province, and it found that 22.7% of them belonged to class 3 or 4 bridge, with unhealthy working conditions or inadequate bearing capacity (Shen and Zhou, 2007). It is obvious that investigating and finding bridge's defects and damage, and evaluating the carrying capacity of old bridge are the technical basis of bridge maintenance, reinforcement or reconstruction design, which have important theoretical significance and engineering application value.