Research On Steel Tubular Concrete Column Strengthened With CFRP Under Blasting

In recent years, the blasting load reactions of the structure arewidely studied due to frequently occurring of terrorist attack and blasting accidental which bring about a large number of casualties and economic loss in the whole world. Pier failure control is the key to stop bridge structures from continuous collapsing under blasting load. The safety level of structure will be promoted because of blasting-resistant design is considered. Steel tubular concrete column is widely used in civil engineering. It has theoretical significance and engineering value that study on reinforcing of structure to resist blasting load. In this paper, the dynamic responses of steel tubular concrete column, which is Carbon Fiber Reinforced Polymer (CFRP) strengthening, under blasting loading are researched. The main contents are included as follows:Firstly,CFRP strengthing can greatly improve the antiknock ability of steel tubularconcrete column. Two models, of which scaled-distance are 0.19, were created by Fluid-solid Coupling method to analysisthe dynamic responses of steel tubularconcretecocolumn under blasting load. One is basic model that only steel tubularconcrete column. The other one is CFRP strengtheningsteel tubular column. The boundary conditionsof two models are fixed. The effectof reflected blast wave is considered in the two models. Analysis and Comparison the numerical simulation result between CFRP strengthening and unreinforced of steel tubular concretecolumn in many aspects, such as the effects of plastic strain, Mises stress, effective strain, maximum displacement and residual deformation.Secondly,whether the pier column with expanded foundation or pile foundation, the antiknock performance of the pier column with fixed support is better than that of the pier column with sliding support.The CFRP strengthening modelswith rectangular section, of which scaled-distance are 0.63, were created by CONWEP method to analysis the dynamic responses of steel tubular concrete column under blast loading. In the models, the bearing plate is simplified as a rigid body, where the spring element is used to simulate the restriction of the upper structure of the bridge. At the bottom of the models, fixed end is used to simulate expanded foundation and soil spring is used to simulate the soil action on pile body.The third, compared with spread foundation and pile foundation of steel tubular concrete columns that are strengthening by CFRP. The deformation is increase and the internal forces are reducing for the columns of pile foundation.The pier columns become softness due to interaction of pile-soil. Under blast loading, the maximum displacement of the column with pile foundation is larger than that of the column with spread foundation. The stress and strain of the column with pile foundation are less than that of the column with spread foundation. The right types of foundations and supports are required to select in blast resistant design of bridge column.