林区桥梁动荷载冲击系数的试验研究

STUDY ON IMPACT COEFFICIENT OF FOREST BRIDGE LIVE LOADS

原条运材车辆是林区桥梁的主要荷载型式,运材车辆荷载对桥梁的动力作用同一般公路桥梁的车辆荷载相比有很大的区别。在林区桥梁设计中,过去一直套用交通部的标准,由于动荷载冲击系数偏低,致使林区桥梁的设计可靠性与安全使用受到一定的影响。通过十几座林区桥梁的振动试验,本文对两种原条运材车辆对于跨径为15m、20m、25m钢筋混凝土简支梁桥动力作用的实测分析,提出适合我国林区运材车辆荷载的冲击系数公式,以及冲击系数(1+μ)与运行速度V、桥梁跨径l之间的经验曲线。这对填补我国林区桥梁设计理论的空白,发展林区公路桥梁建设,增加设计可靠性与安全使用都是极为有益的。

Log-track is the main form of loads in forest bridges, the bridge dynamic actions caused by log-track are quite different from those caused by normal truck in highways bridges. For the design of forest bridges, the specifications of the ministry of transportation was applied indiscriminately in the past, because of the lower impact coefficient of live loads, the design reliability and the safety performance of forest bridges are influenced to some extent. viberation tests were conducted with more than 10 forestry bridges, analysed the dynamic action for simple supported concrete bridges of spans of 15, 20 and 25 meters carrying two kinds of log-truck. The impact coefficient formula and the empirical curve which relates to the impact coefficient 1+μ, speed V and bridges span L, which are suitable to the log-truck loads in the forest region of China. It fills in the gaps in the design theory for forest bridges. It is also benefit to the development of forest bridges. It is also benefit to the development of forest bridges construction, the increment of design reliability and safety performance.