中支点顶升法控制钢混组合梁桥面板裂缝

南京市浦口区大桥北路快速化改造工程紧邻地铁S8号线,匝道桥与既有江北大道预留QC匝道跳水台连接。其中匝道第二联上跨既有地铁S8号线泰山新村地铁站1号口,为减小预应力混凝土箱梁浇筑施工时支架荷载对地下既有构筑物的影响,采用(35.69+37+36)m钢混组合连续箱梁。钢混组合梁施工重点是要控制混凝土桥面板墩顶负弯矩区开裂,文章主要简要分析墩顶桥面板开裂影响因素和目前常用控制措施和施工方法,结合大桥北路钢混组合梁采用顶升、后浇负弯矩区控制开裂的方法进行阐述,为后续设计和施工钢混组合梁桥面板提供依据。

The expressway reconstruction project of Bridge North Road in Pukou District of Nanjing City is close to Metro Line S8,and the ramp bridge is connected with the existing Jiangbei Avenue reserved QC ramp diving platform.In order to reduce the influence of support load on prestressed concrete box girder during pouring construction,(35.69 + 37 + 36)m steel-concrete composite continuous box girder is used to reduce the influence of support load on the existing underground structure during the pouring construction of prestressed concrete box girder in order to reduce the influence of the second ramp on the existing subway S8 line Taishan Xincun subway station.The key point in the construction of steel-concrete composite beam is to control the cracking in the negative moment zone of the pier top of the concrete bridge deck.this paper mainly briefly analyzes the influencing factors of the cracking of the pier top bridge deck and the common control measures and construction methods at present.Combined with the steel-concrete composite beam of the north road of the bridge,the method of controlling cracking in the lifting and post-pouring negative moment zone is expounded,which provides the basis for the subsequent design and construction of the steel-concrete composite beam deck.