In order to carry out the controlled blasting of two 200 m reinforced concrete bridges(an old continu-ous beam bridge and a new arched bridge)under complex environment,the piers of the two bridges,the webs of the continuous beam and the double-curved arch foot of the arch bridge were selected as the blasting locations,and the main bearing parts of the bridges were destroyed.Furthermore,deep hole blasting method and shallow hole blasting method were adopted for the pier and main beam respectively to improve the construction safety and efficiency.Spe-cifically,large-diameter vertical holes facing the pier from the bridge were adopted for the blasting of the pier to over-come the influence of pier arc face on the calculation of minimum resistance line and reduce the drilling workload.Additionally,the two bridges were detonated span by span in the same direction from south to north,with an equal delay interval between two adjacent spans.At the same time,the detonation time of the new bridge is 50 ms later than that of the old bridge.To reduce the damage of blasting vibrations and ground touch vibrations,millisecond delay con-trolled blasting was adopted,and the direction of the minimum resistance line was deviated from the near shore pro-tection object.Meanwhile,in order to control the flying stone,sandbags were piled on the abutment,and the blasting objects were bounded with wire meshes and covered with multilayer bamboo basketries.After detonation,the bridge collapsed span by span as expected,the vibrations and flying rocks were controlled well.
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