Experimental study on fatigue performance of damaged PPC cable-stayed bridge main beam after crack grouting reinforcement
In order to further investigate the fatigue performance of the main beam of the damaged partially prestressed concrete(PPC)cable-stayed bridge after crack grouting reinforcement,a scaled model of the PPC cable-stayed bridge section with significant fatigue and static damage to the main beam for crack grouting reinforcement was used,and fatigue and post fatigue static load tests were carried out.The results show that under fatigue load,the grouting cracks do not crack again,and the stiffness of the structural system decreases rapidly in the initial stage of fatigue loading(within about 200 000 times),and gradually in the later stage.After 2.5 million times of fatigue loading,the structural system stiffness of the main beam at L/4,L/2,and 3L/4 sections decreases by 12.83%,9.48%,and 13.62%,respectively,which is larger than that of the original main beam under the fourth round of fatigue loading.However,at the end of fatigue loading,the stiffness of the structural system is still greater than the initial structural system stiffness of the original main beam under the fourth round fatigue loading.The crack grouting treatment can effectively restore the crack resistance strength and structural system stiffness of the main beam of PPC cable-stayed bridge.With the increase of load,the grouting cracks gradually open,but the position of the maximum crack width shifts.At the same time,new cracks are constantly generated,and the range of crack distribution area increases.The effect of epoxy resin adhesive greatly delays the development of crack width and improves the crack resistance of the main beam.Epoxy resin adhesive can not only repair the crack interface of concrete,but also effectively recover the bond slip damage between steel bars and concrete.The main beam of the severely damaged PPC cable-stayed bridge still has strong fatigue resistance after crack grouting treatment,and the crack resistance and stiffness of the main beam after fatigue are greatly restored.
bridge engineeringconcrete cable-stayed bridgepartial prestressgrouting reinforcementfatigue performancemodel test
万方数据
维普
