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Using finite element software, using the single beam method and the beam lattice method, the finite element model of a large-width span special-shaped single-box multi-chamber PC cast-in-place box girder and the ANSYS threedimensional solid refined finite element model are established, and the stress calculation results of the single beam model and the beam lattice model are compared with the stress results of the ANSYS solid model from the structural stress, firstly, the accuracy of the finite element calculation methods of the two rod systems is discussed, and then the three finite element models are used to analyze the transverse stress distribution law of each mid-span section under lane loadto explore the variation law of shear hysteresis coefficient under different width span ratios. The results show that compared with the ANSYS solid element calculation results, the calculation results of the beam lattice method are in good agreement with the ANSYS results. The single-beam method cannot reflect the real stress state of a single-box multi-chamber wide-body box girder, nor can it reflect its shear hysteresis effect. Under the action of lane load, comparing the shear hysteresis coefficient under different width-span ratios, it can be seen that the larger the width-span ratio, the more obvious the shear lag effect. For single-box multi-chamber wide bridges, the beam lattice method can directly give the axial force, shear force and bending moment required for design review compared with the ANSYS solid model, and has good calculation accuracy. In the extreme case, i.e., when the uplink line is fully loaded and the downline is unloaded, the maximum deviation rate between the shear hysteresis coefficient of the beam lattice model and the shear hysteresis coefficient of the single-beam model is 91.9%, and it can be concluded that for the wide bridge, the load calculation cannot be carried out by the single-girder model. The research methods and conclusions obtained in this paper can provide a reference for the design review of similar bridges.
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