节段预制胶拼构件轴拉强度试验研究

胶接缝抗拉强度是节段预制拼装混凝土梁抗裂性检算的重要依据。为研究节段预制胶拼构件轴拉强度,设计制作了4个预制胶拼单键混凝土轴向拉伸构件,研制了轴向受拉加载装置,进行了胶拼构件轴向拉伸破坏试验。试验结果表明,胶拼构件轴向受拉破坏过程发展较快,具有明显的脆性破坏特征。构件受拉断裂位置为胶接缝附近,胶接缝的破坏属于混凝土内聚破坏。试验构件的接缝抗拉强度为2.94～3.24 MPa,平均值为3.17 MPa,具有一定的抗拉性能。将试验结果与相关规范进行对比,并简要分析轴拉强度影响因素。建议在预制节段胶拼桥梁的抗裂性设计中,可以适当考虑胶接缝的抗拉强度,减少预应力钢筋用量,提高设计经济性。

Experimental Study on Axial Tensile Strength of Precast Segmental Concrete Members

The tensile strength of the epoxy joint is an important factor for checking the crack resistance of precast segmental concrete beams. Four prefabricated concrete members with single key are designed and manufactured to study the axial tensile strength of precast segmental concrete members. The loading device under axial tension is developed and the failure experiments of the components under axial tension are carried out. The test results show that the axial tensile failure of the members develops rapidly and exhibits obvious brittle failure characteristics. The tensile fracture of the members is near the epoxy joint. The failure mode of the epoxy joints is cohesive failure. The tensile strengths of the joints are 2.94～3.24 MPa with an average value of 3.17 MPa. The epoxy joint has good tensile properties. The test results are compared with the relevant specifications, and the influencing factors of the axial tensile strength are briefly analyzed. It is suggested that the tensile strength of the epoxy joint should be considered in the crack resistance design of precast segmental concrete beams so as to reduce the amount of pre-stressed reinforcement and project cost.