MECHANICAL MODELS OF ROCK-BOLT CRANE GIRDER IN ULTIMATE LIMIT STATE

摘要

On the basis of the results of emulational material model test of rock-bolt crane girder, the whole process of the failure of rock-bolt crane girder under crane wheel load was analyzed. It seems that the crane wheel load is sustained mainly by the adhesive tensile force of vertical interface and the compression of inclined interface before the crack of interface. However, the adhesive tensile strength of rock-concrete interface should not be taken into account in the analysis of rock-bolt crane girder for the reliability in the long run. The limit state of tensile bolts yield and the concrete or rock over the edge of compressive zone crush was proposed to be the ultimate limit state, on which three equilibrium equations were deduced for the design and analysis of rock-bolt crane girder. Moreover, the effect of release stress seems to be equivalent to prestressing a certain tension in the bolts of rock-bolt crane girder before crane operates. Therefore, we proposed that release stress should not be considered in the analysis of rock-bolt crane girder since it is independent of the bearing capacity of rock-bolt crane girder in ultimate limit state.