CFRP-PCPs复合筋加固钢-混组合梁负弯矩区抗裂试验与理论计算OA北大核心

In order to overcome the industry problem that the concrete slab in the negative moment region of the steel-concrete composite beam is prone to cracking causing weakening of stiffness.Prefabricated CFRP-PCPs(car-bon fiber reinforced polymer-prestressed concrete prisms)composite reinforcement is used as the web reinforcement of the middle support.Five steel-concrete composite continuous beams with composite reinforcement and one ordina-ry composite continuous beam are designed and manufactured with the number of composite reinforcement,pres-tressed tension level and section size as the main parameters,the crack resistance in the negative moment zone un-der single-span single-point load is studied.The results show that:The composite reinforcement can significantly enhance the section stiffness of the middle support,the crack control ability in the negative bending moment zone is significantly improved;compared with ordinary composite beams,the cracking load of composite reinforcement beams is increased by nearly 30%,the number and width of cracks are reduced by nearly 50%;the area of compos-ite reinforcement is the main factor to improve the crack control ability,the influence of prestress level and section size on cracking load is weak;the cracking load of composite reinforcement is positively related to the level and area of prestress.Among them,the level of prestress is the key factor affecting the effective duration of composite rein-forcement.Based on the existing theoretical and experimental data,in this paper,the calculation formulas of the cracking load in the negative moment region of the steel-concrete composite continuous beam with CFRP-PCPs composite reinforcement and the cracking load of the composite reinforcement are proposed,the calculated results are in good agreement with the test values,it can provide reference for the practical engineering application of com-posite reinforcement in steel-concrete composite beam bridges.