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The 15th to 44th span of a high-speed interchange main line bridge is a 30×15 m reinforced concrete frame bridge. After reinforcement for many times, the frame bridge still has many defects such as damage, exposed reinforcement and cracking, It is necessary to demolish them and build new bridges on both sides at the same time. Considering the convenience of the construction of the new bridge, it is proposed to demolish the longitudinal beams on the left and right sides of the old bridge first. The nearest clear distance between the new bridge pile foundation and the old bridge is about 1.4 m. The impact drilling construction technology is proposed. The impact drilling adopts the hammer with a weight of 5 t and an impact time of 5 ms. In order to understand the influence of impact drilling construction on the demolition of longitudinal beams on both sides of adjacent frame bridge, the finite element software was used to establish a part of the separated common node model of frame bridge, and the mechanical response of adjacent frame bridge under the impact of impact drilling construction was numerically simulated. The results show that: the maximum vertical displacement of the frame pier column is 0.955 mm, and the lateral and longitudinal horizontal displacement outside the bridge deck are 0.068 mm and 1.63 mm respectively. The stress of the frame bridge structure does not reach its ultimate failure value. Using the impact drilling technology construction, considering the need for multiple impacts in the process of impact drilling, it will cause the settlement value of the adjacent frame bridge and the transverse horizontal displacement of the bridge deck is large, which causes the structure to bear greater safety risks. It is recommended to build a new bridge after all the frame bridges are demolished.
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