Analysis of dynamic response of base slab in blasting demolition of reinforced concrete girders

Blasting demolition of reinforced concrete girders was widely applied in the deep foundation pit engineering, but the influence of the blasting load to the permanent structure deserved considered for the short distance between the center of the blasting and the permanent structure. Based on the time-history analysis method, the acceleration time-history curves which was transformed from velocity time-history curves was introduced as the calculating loads and the velocity time-history curves was obtained from field measurement. Then the dynamic response of base slab subjected to blasting load of reinforced concrete girders was calculated through the ANSYS/LS-DYNA software. At last the stress, velocity and displacement caused by blasting was analyzed. It was founded that the maximum and minimum principal stress were 6.7 MPa and 8.2 MPa separately and the maximum velocity and displacement were 14.8 cm/s and 0.58 mm separately. The elements didn´t yield in the process, so the base slab was safe.