Study On Reinforced Concrete Columns Anting Rockfall Impact Test

For the security risk of bridge structures in western mountain of China by falling rocks and providing theoretical and practical techniques about security protection of the piers of mountain bridges in China,according to the prototype of the typical bridges belong to the DuWen and ChuanWen road, using the way of model test and numerical simulation calculation to study on the injury effects of the piers of mountain bridge caused by hiting of falling rocks in mountainous areas and to give some practical treatment measures for impacting resistance.In the model test,in order to research on the state of injurys and damages about the piers of mountain bridge after hiting of falling rocks,designing two reinforced concrete components,one is full scaling with the diameter of1.2m and another is scaling with the diameter of0.6m. There are four impacting blocks which are outsourcing plate and made of concrete.They are designed by European standard. In the test,four types of the quality of the blocks are selected:0.25t,0.5t,1t and2t.And three contact forms of hiting are used:Parallel-Prism,V-shaped edge and Bottom surface contacts. Measuring the impacting acceleration of typical conditions is using the acceleration measuring instrument and wireless sensor located in the perforated box at the top of impact test block.Makingal the test block drop vertically from the specify height by the lifting of the gantry crane,and then decoupling device release the test block.Through the conversion of potential energy and kinetic energy, the test block galet enough impacting-energy designed before the test by the mean of free falling.Researching the damage and destruction state of reinforced concrete members at the different kinds of impact energies. The test results show that the injury degree of piers is directly related to the form of the contact surface of hitting under the same conditions of quality and impact velocity. After increasing the roughness at the bottom, the impact bewteen the piers and blocks is more coincide with the actual case, all the work conditions are impact at the edge or corner.If specimen impact the piers by the case of plane contact,the damage area of piers is related to the contact area of theimpact. If using the same level of energy impact the piers repeatedly on the same site, damage range and depth are increasingly serious.Finally,it will lead to significant improving of damage level or even failure. At the same time,proposing three kinds of defensive protection measures that thickening the concrete coverjacketing plate or applying the concrete filled steel tube members.By the test,verifying the conclusion that thickening the concrete cover can effectively reduce the damage degree of reinforced concrete members bearing the repeated impact of falling rocks.And proofing that the defensive protection measures of jacketing plate will efficiently decrease the injury degree of the reinforced concrete members caused by the repeated impact of falling rocks because of the consumption of energy by its deformation, thus reducing the damage level of the widget.In addition,establishing numerical calculation models to contrast between different kinds of typical test conditions.By the comparison of acceleration achieved by calculation and test.confirmed the effectiveness of test results and the reliability of the calculation parameters,to laying the foundation of parameterized numerical simulation analysis.