Method for detecting bridge impact coefficient based on dynamic load test

Abstract

The invention discloses a method for detecting a bridge impact coefficient based on a dynamic load test. The method comprises the steps of: (1) detecting and recording deflection data of a bridge; (2) drawing a deflection schedule curve of the bridge; (3) obtaining a bridge impact coefficient muij corresponding to each pair of adjacent wave peak value Xij and wave trough value Yij on the i-th deflection schedule curve of the bridge; (4) obtaining a bridge impact coefficient mui corresponding to a vehicle speed vi; (5) repeating the step (3) and the step (4) until n bridge impact coefficients mu1, mu2, ...mun corresponding to n different vehicle speeds v1, v2, ...vn are obtained; and (6) obtaining a bridge impact coefficient mu. The method for detecting the bridge impact coefficient based on the dynamic load test, disclosed by the invention, has the advantages of rational design and convenience in realization; the bridge impact coefficient obtained by detection is safer, so that dynamic effect of the bridge structure can be reflected more exactly and more rationally under the function of the load of movable vehicles; the practical problem that the conventional impact coefficient cannot reflect exactly that the movable load acts on the bridge structure in form of multiple load points is solved efficiently; and the method for detecting the bridge impact coefficient based on the dynamic load test, has strong practicability and high popularization and application values.

Description

technical field [0001] The invention belongs to the technical field of construction and traffic bridges, in particular to a method for detecting the impact coefficient of a bridge based on a dynamic load test. Background technique [0002] The detection of bridge impact coefficient has extremely far-reaching significance for bridge design, maintenance and reinforcement. If the impact coefficient of bridge structure cannot be accurately detected, it will lead to unreasonable design of new bridges or untimely maintenance and reinforcement of old bridges, which will cause bridge damage caused by vehicle loads. In severe cases, major accidents will occur, causing loss of people's lives and property. [0003] In the bridge design codes at home and abroad, the vertical static effect of the vehicle load is multiplied by an increase factor (1+μ) as the total vertical load effect included in the dynamic action of the vehicle load. In the current bridge design codes of various countr...

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Problems solved by technology

Foreign research in this area has made some progress. For example, in the Ontario Code of Canada, the dynamic coefficient has been expressed as a function of the fundamental frequency of the bridge; It is pointed out that the dynamic coefficient is related to vehicle characteristics, vehicle speed, bridge deck flatness, and the dynamic characteristics of the bridge span structure itself, but it does not fully reflect the influence of these factors on the dynamic coefficient. Only the dynamic characteristics of the bridge structure are considered. The single parameter of the fundamental frequency of the bridge structure is considered, which is different from the actual situation.

[0004] When the early experimental test method is based on the dynamic strain or deflection time-history curve recorded by the sports car test to detect the impact coefficient μ of the control section, it is not clear which point to choose the time-history curve. In addition, only the vehicle is considered when the impact coefficient is obtained through the time-history curve processing. The "impact" on the test section (generally also the mid-span) when driving on the mid-span section, without considering the impact of the vehicle driving on other positions on the bridge on the test section, the measured bridge impact coefficient cannot accurately reflect whether the moving load is Practical problems with multiple "point" loads acting on bridge structures

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