桥梁无缝伸缩缝用改性聚氨酯研发及足尺试验研究

Development and Full-Scale Tests of Modified Polyurethane-Based Seamless Expansion Joints for Bridge

利用足尺试验与有限元模型,研究了采用聚氨酯(PU)材料制备的桥梁无缝伸缩缝的服役性能。首先,制备了3种不同配合比的改性PU材料,测试并对比了它们的初凝时间、拉伸强度、撕裂强度、硬度、路面附着力、吸水率、抗车辙及老化性能,确定了最适用于桥梁无缝伸缩缝的最优PU配合比方案。然后,采用所选的PU材料设计制作了4个足尺无缝伸缩缝试验件,并建立了与之相匹配的有限元模型。最后,通过对比分析试验实测与有限元计算结果,表现出所设计的无缝伸缩缝在单轴拉伸/压缩、竖向变形及低周疲劳荷载工况下均能保持优异的服役性能。此外,研究结果还表明在改性PU无缝伸缩缝与路面之间设置45°倾角可以显著改善受力状态,避免接缝处早期开裂。

The service performance of seamless expansion joints made of polyurethane(PU)material for bridge structures was studied using full-scale tests and finite element models.First,three modified PU materials with different mix ratios were prepared.The initial setting time,tensile strength,tear strength,hardness,road adhesion,water absorption rate,resistance to rutting,and aging performance were tested and compared to determine the optimal PU mix ratio for seamless expansion joints for bridges.Then,four full-scale seamless expansion joint specimens were designed and fabricated using the selected PU material,and a corresponding finite element model was also developed.Finally,by comparing the experimental measurements and the finite element calculations,it is shown that the designed seamless expansion joint exhibits excellent service performance under uniaxial tension/compression,vertical deformation,and low-cycle fatigue loading conditions.Additionally,the research results indicate that setting a 45°inclination angle between the modified PU seamless expansion joint and the road surface could significantly improve the stress state and prevent early cracking at the joint.