Numerical simulation and field test studies on mechanical behavior of steel plate girder strengthened by external prestressed tendon

To investigate the mechanical behavior of the steel plate girder strengthened by the external prestressed tendon, three typical and representative steel plate girders (K2, K3, and K4) are taken as the research background. Based on their structure characteristics and safety assessment, the effective and feasible reinforcement scheme of the steel plate girder is proposed first. And then, a three-dimensional finite element model of the steel plate girder strengthened by the external prestressed tendon is set up in consideration of the prestress loss of the prestressed tendon and the advanced finite element technique (for instance, element birth and death capability). After that, this model is calibrated on the basis of the results from the field test. And finally, a series of numerical simulation analyses are performed with application of the nonlinear finite element method program Abaqus to investigate the mechanical behavior of the steel plate girder. The results show that the reinforcement scheme has great influence on the deflection of steel plate girder and the stress of steel plate girder; whereas it has little relation with the contact stress of the interface between the upper and lower I-beams and the stress of the bolt. The fracture safety factors of K2, K3, and K4 after reinforcement are 3.04, 3.76, and 3.35, respectively. It meets the primary goal of this proposed reinforcement scheme that their fracture safety factors are all greater than 3.00 under the design stress. The reinforcement scheme is good and effective, and the steel plate girder has good and stable working performance after reinforcement. It can completely meet the reinforcement design requirement of the steel plate girder. Therefore, this study can provide the technological support and the theoretical basis for engineering applications.