公路工程

拼宽桥梁接缝的弯曲性能对桥梁的安全性和耐久性有重大影响。为明晰接缝材料参数对接缝弯曲性能的影响，制作了1根UHPC接缝试件(M-1)和1根NC接缝试件(M-2),通过四点弯曲试验，探究了不同接缝材料梁的破坏形态、变形能力、弯曲性能；通过ABAQUS有限元软件建立UHPC接缝的模型，对试验结果进行验证，并分析了UHPC接缝宽度、厚度、配筋率变化对接缝弯曲性能的影响。结果表明：(1)UHPC接缝相较于NC接缝，在抗弯承载力和刚度方面有显著提升，极限荷载提高24.5%,峰值位移提升136.3%;(2)接缝宽度的减少对拼宽接缝的抗弯极限承载力和刚度影响不大，建议在满足锚固长度规范要求下，可将接缝宽度降低至15 cm,以减少UHPC材料用量并改善接缝受力性能；(3)接缝厚度的增加能有效降低挠度，改善桥梁的横向受力，但厚度超过25 cm后，力学性能改善效果递减，建议接缝厚度控制在25 cm以内；(4)接缝配筋率的增加能提高极限承载力，但过高会降低延性，建议配筋率控制在2.1%以内，以实现最佳性能；(5)试验结果与有限元模型计算结果拟合较好，但研究中未考虑环境因素对试验的影响，今后可将荷载-环境耦合因素考虑在内。

The flexural performance of widening bridge joints has a significant impact on the safety and durability of bridges. To clarify the influence of joint material parameters on flexural performance, one UHPC joint specimen(M-1) and one NC joint specimen(M-2) were fabricated, through four-point bending tests, the failure modes, deformation capacity, and flexural performance of beams with different joint materials were investigated; a model of the UHPC joint was established using ABAQUS finite element software to validate the experimental results, and the effects of UHPC joint width, thickness, and reinforcement ratio on the flexural performance of the joint were analyzed. The results show that:(1)Compared with the NC joint, the UHPC joint exhibits significant improvements in flexural bearing capacity and stiffness, with an ultimate load increase of 24.5% and a peak displacement increase of 136.3%;(2)A reduction in joint width has little effect on the ultimate flexural bearing capacity and stiffness of the widening joints, it is recommended that the joint width be reduced to 15 cm to minimize UHPC material usage and improve the mechanical performance of the joint, provided that the anchorage length requirements of the code are met;(3)An increase in joint thickness effectively reduces deflection and improve transverse stress distribution in the bridge, however, when the thickness exceeds 25 cm, the improvement in mechanical performance diminishes, it is recommended that the joint thickness be controlled within 25 cm;(4) An increasein the joint reinforcement ratio enhances the ultimate bearing capacity, but an excessively high ratio reduces ductility, it is recommended that the reinforcement ratio be controlled within 2.1% to achieve optimal performance;(5) The experimental results fit well with the calculation results of the finite element model, however, the impact of environmental factors on the experiment were not considered in this study, future research may incorporate load-environment coupling factors.