预应力RC-UHPC组合箱梁的受弯性能

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中图分类号：U443.35 文献标志码：A 文章编号：2096-6717（2025）06-0168-09

Abstract： In order to explore a new type of composite box girder with light hosting weight，convenient construction and high durability，a new prestressed RC-UHPC composite box girder with ultra-high performance concrete（UHPC）as web and botom plate and reinforced concrete （RC）as top plate was designed and fabricated.A flexural test wascarred out to investigate the failure mechanism and failure mode of the specimens;the finite element software was utilized to simulate the test，and the calculation accuracy ofthe finite element method was verified by comparing the finite element calculation results with the test data，on the basis of which 16 finite element analysis models were established to analyse the influence of various parameters on the flexural strength. The results show that the failure mode of the specimen is adequate reinforcement failure， which shows that theRC top slab in the pure bending section iscrushed after the yielding of the longitudinal tensilereinforcement and the fracture of some prestressing reinforcement; the tensile strength of UHPC and the reinforcement ratio of prestresing tendons exert a greater influence on the flexural strength;the longitudinal strainof the specimen’sis basically consistent with the plane section assumption in the height direction. Combined with the theoretical analysis，the formulas for calculating the flexural strength were proposed.The ratios of the calculated value to the testvalueand the finite element calculated value are1.O14 and 0.960， respectively ，which indicates a high calculation accuracy.

Keywords： bridge engineering；composite box girder； flexural strength；experimental study；ultra-high perfor manceconcrete

箱梁是桥梁上部结构常用的结构形式，但各类箱梁在建造和实际使用过程中存在一些不足：混凝土箱梁的截面尺寸与自重较大，吊装难度较高，限制了其在城市桥梁中的应用，同时，在运营中存在挠度大和裂缝多等问题1；由于钢梁和混凝土板在环境变化时的温度梯度不同，且混凝土板与钢梁的刚度差别过大，钢-混凝土组合箱梁桥面板更易开裂，剪力连接件还存在疲劳问题[2-3]；钢箱梁造价相对较高，存在疲劳损伤、抗腐蚀性能弱等缺点。（剩余11540字）