Experimental Study On Residential Bearing Capacity Of RC Short Column Under Impact Damage

Concrete has been widely used for150years, due to its physical andmechanical properties, the material sources and the project cost, etc, it is widelyused, compared to other construction material, eg. steel, timber and masonry.Wherever in China or in the world, its application is extensive in civil engineeringstructure.Apart from dead load, live load and seismic action, structures may suffer fromaccidental load in its service time. The impact with high energy will lead to failureand even collapsed, In spite of the impact energy is not so severe to completelydestroy the structure in many cases, bearing capacity of the structure will decreaseand dynamic characteristics will change. Therefore, it is great significance to studyan effective evaluation method of impact damage degree to evaluate residualbearing capacity and structure reinforcement.With the drop hammer machine, a series of impact experiments of thereinforced concrete prism specimens was carried out in the laboratory. The levelsof damages were detected by ZBL-U510nonmetal ultrasonic instrument andresidual bearing capacity of R.C concrete was available by the5000kN pressmachine. Finally, the simulation analysis of the hammer test was done with theANSYS/LS-DYNA. There are some research works as follows:(1) The reinforced concrete short columns were tested under the axial impactload, with the drop hammer machine. The impact force and the strain of steel andconcrete were measured.(2) An ultrasonic instrument was used to test concrete columns before andafter impact, then the change of acoustic parameters in damaged concrete wasgained. The damage factor D and the nonlinear coefficient β of ultrasonic weremeasured to establish relationship between D, β and the residual bearing capacity.(3) The axial force-displacement curve of the damaged reinforced concretespecimens were gained and the elastic modulus, ultimate bearing capacity and thepeak displacement was changed.(4) The finite element software ANSYS/LS-DYNA was used to simulate theimpact process, then compared modeling results and test results.