公路工程

简支梁桥桥面伸缩缝多,导致行车不舒适,因而多跨简支梁采取桥面连续的措施被广泛应用。以海南铺前大桥为背景,结合钢-超高韧性混凝土STC (Super Toughness Concrete)轻型组合桥面技术,对跨断裂带引桥提出了受力性能优良、震后易修复的简支变桥面连续结构。为探明简支变桥面连续结构的受力性能,对方案开展负弯矩足尺模型试验,结果表明,裂缝开展集中于螺栓连接带区域,破坏模式为螺栓剪断,U肋未屈服。这意味着在地震荷载下简支变桥面连续结构先破坏,从而保护钢箱梁主体结构。在此基础上,建立了实桥ANSYS有限元模型和试验方案的有限元精细化模型,有限元模拟与试验值吻合良好。最后根据前述试验和有限元计算结果,进行了参数分析,另外提出了2种桥面连续方案—端隔板开孔方案(方案1)和增加短肋方案(方案2),并进行了有限元计算。结果表明,2种方案均能满足正常使用极限状态的使用要求。与试验方案相比,方案1和方案2均可以实现保护箱梁主体结构的目的。方案2由于增加了短肋,从而减小了局部轮载下STC层的纵向拉应力,使整体+局部计算结果仅12. 1 MPa,小于方案1的计算结果 21. 3 MPa和试验方案的计算结果19. 7 MPa。从承载力来看,试验方案1和方案2的承载力基本相同,方案1最小。综合来看,方案2更优。

Because of the large number of expansion joints on bridge decks of simply supported beam bridges,it is uncomfortable to drive. Therefore,the measures for multi-span simply supported beam bridges to take continuous decks are widely used. In this paper,based on the Hainan Puqian Bridge,combined with the Steel-Super Toughness Concrete( STC) lightweight composite deck technology,a simply supported bridge with continuous decks with excellent stress performance and easy to repair after earthquake was proposed for the approach bridge across the fault zone. To explore the mechanical behavior of the continuous bridge deck of simply supported bridge,a full scale model test of negative bending moment was carried out for the schemes above. Test results showed that the crack focused on bolt connection area. From the failure mode,U ribs did not yield and the bolts were cut. This means that under seismic loads the continuous deck structure was destroyed firstly to protect the main structure of the box girder. On this basis,the ANSYS finite-element models and ABAQUS finite-element models of the test scheme of the Hainan PuQian Bridge with fault zone were established. Finite element simulation agreed well with the test results. Finally,based on the results of the previous tests and finite element calculations,parameter analysis was performed. Two types of schemes with continuous decks were proposed and finite element calculations were performed. One scheme was that the diaphragm was opened( scheme 1) and another scheme was the short rib scheme( scheme 2). Results showed that both schemes could meet the requirements of serviceability limit state. Compared with the experimental scheme,both scheme 1 and scheme 2 could achieve the purpose of protecting the main structure of the box girder. Due to the increase of short ribs in scheme 2,the longitudinal tensile stress of the STC layer under local wheel load is reduced,and the overall + local calculation result is only 12. 1 MPa,which is less than the calculation result of scheme 1 with 21. 3 MPa and the test scheme calculation result with 19. 7 MPa.From the bearing capacity,the carrying capacity of the test scheme is basically the same with scheme 2,and scheme 1 is the smallest. In a comprehensive view,scheme 2 is a better scheme.