Deformation Evaluation in Welded Rebar Parts for Pylons and Its Application in Changtai Yangtze River Bridge

The prefabrication and assembly of rebar parts can reduce construction costs and time while enhancing construction quality and safety. The primary objective of this paper is to quantify the overall stiffness of rebar parts. A three-dimensional rotational stiffness solution model of welded spots is proposed from the perspective of revealing the overall stiffness required for welded rebar parts. Considering the influence of the rebar diameter, 105 sets of T-type welded rebar specimens and two types of loading devices were designed, and a graded loading failure test was carried out. On this basis, the constitutive model of welded spots and the method for evaluating the model parameters are presented. Moreover, in order to verify the rationality of the proposed constitutive model and its parameter values, the deformation of welded rebar parts for the middle pylon of Changtai Yangtze River Bridge was tested onsite. The results show that analyzing the three-dimensional rotational stiffness of welded spots is the key to obtaining the overall stiffness of welded rebar parts, and its rotational stiffness decreases rapidly after an elastic platform. The constitutive model parameters of welded spots such as initial stiffness, elastic rotation angle, and stiffness degradation rate conform to Gaussian distribution. When the model parameters of welded spots are taken as the mean value of the distribution function, the simulated values are basically in good agreement with the measured values, with a maximum error of only 8.54%, indicating that the proposed constitutive model can better quantify the overall stiffness of the welded rebar parts.