Method for determining lap joint length of rebars of recycled concrete beam

The invention provides a method for determining the lap joint length of rebars of a recycled concrete beam. The method comprises the following steps: step 1, determining characteristic parameters of the recycled concrete flexural member, wherein the characteristic parameters comprise recycled concrete cube compressive strength fcu, lap joint steel bar diameter d, volume hooping rate [rho]sv at the lap joint, recycled aggregate substitution rate [delta]r, lap joint steel bar clear distance D, lap joint steel bar yield strength fy and lap joint steel bar ultimate strength fu; and step 2, when the bearing capacity of the recycled concrete flexural member is in the limit state, according to the characteristic parameters of the recycled concrete flexural member, calculating the steel bar lap joint length Lsy when the steel bars at the lap joint position are in the yield state and/or the steel bar lap joint length Lsu when the steel bars at the lap joint position are in the limit state. The method can accurately de