Computing Creep Secondary Internal Forces in Continuous Steel–Concrete Composite Beam Constructed through Segmented Pouring

Abstract

A novel approach is proposed to compute the secondary internal forces caused by creep in a continuous steel–concrete composite beam that is constructed through segmented pouring. The key to solving the equations with the force method is related to the computation of the relative rotational angles, and addresses three factors: creep constitutive equations, material components of structures, and time status. Considering the effects of these factors, the relative rotational angles of a plain concrete beam and composite beam are deduced, respectively, based on concrete creep theory, and address two conditions: instantaneous deformability with no creep effect and time-dependent deformability with creep effect. By substituting the corresponding relative rotational angles into the force-method equations, the secondary creep forces are solved. Finally, a time-dependent analysis on a two-span continuous composite beam constructed through segmented pouring is presented. The results show that the negative bending moment at the support of the continuous beam constructed through segmented pouring is smaller than that of a continuous beam constructed through integrated pouring. Due to the effect of concrete creep, the negative bending moment at the support increases with time. The greater the creep effect, the closer the negative bending moment of the segmented-poured beam is to that of the integral-poured beam. It is observed that concrete creep has a significant influence on the deflection of a steel–concrete continuous composite beam. The proposed method is verified by comparing its results with those obtained from detailed finite element analyses.