Numerical Simulation Study On Blasting Demolition Of Multi-span Simply Supported Beam Bridge

In recent years,with the continuous development of the transportation industry,traffic flow has increased dramatically.Many bridges have not met the demand for transportation in today's society,and a large number of bridges are facing demolition.At present,the blasting technology is the most widely used in the bridge demolition project.Many of the surrounding facilities of the bridge to be demolished are complex,and the requirements for blasting technology are quite high.The theory of blasting demolition of bridges lags behind the practice,How to choosing reasonable blasting parameters in actual blasting engineering is a big problem.Numerical simulation technology has been widely used in demolition blasting research and proved to be an effective research method.In this paper,combined with the actual blasting demolition of a multi-span simply supported beam bridge,a quantitative blasting design was carried out for the structural characteristics of the bridge to be demolished,before the formal implementation of blasting demolition,and the finite element of the bridge pier was established by Workbench/Autodyn.For the pier with a diameter of 1.3m,the blasting parameters such as hole depth 0.87m,hole distance 0.5m,unit consumption 0.65kg/m3 and single hole charge 0.43kg are designed to simulate the damage of pier column under blast loading.The damage process,numerical simulation results show that the pier column has better crushing effect under the pre-designed blasting scheme,and the blasting effect is good.The south finite element model of the bridge to be demolished is established by ANSYS/LS-DYNA.The collapse process of the bridge under different schemes is predicted by computer numerical simulation technology.The simulation results show that the collapse direction is adopted when the directional tilt collapse mode is adopted.Easy to control,it can effectively protect the safety and control collapse effect of the new bridge structure close to the bridge to be demolished.The numerical simulation results guide and optimize the blasting design to a certain extent,and the actual blasting effect is in good agreement with the simulation results.