Mechanical Behave Research On Single-column Wide Cantilever Irregular Interchange Bridge

With the rapid development of traffic career in our country, we began to strongly develop the bridge construction. Because of flexible style and beautiful appearance, single-column wide cantilever irregular interchange bridge as an efficient implement three-dimensional interchange traffic system came into being. With the single-column irregular bridge being built constantly, due to the diversity of structure, the mechanical becomes increasingly complex. Therefore, it is particularly important to analyze mechanical performance of single-column irregular bridge.1、Analysis method of irregular bridge can be briefly introduced, combining with the structure form of Harbin Wenchang interchange bridge, availing of grillage theory to briefly summarize how to divide the section of box girder, describe single-cell box girder and twin-celled box girder should follow equal distribute roof and floor principle to divide, multi-cell box girder should divide from cell center in detail, but rotational inertia will be moved to the box girder cancroids section.2、Using grillage theory establishes a finite element model of Harbin Wenchang interchange bridge, analyzes the whole bridge internal force. Through changing the support reactions, curvature radius of curved ramp, pier stiffness, crossbeam arrangement, the paper analyze the internal force of superstructure and substructure in detail. Theoretical analysis show that:single-column diameter is the greatest influence on longitudinal bending moment of interchange bridge upper structure, curvature radius is the greatest influence to longitudinal bending moment of curvature ramp, cross beam and supporting form is the greatest influence on torque and vertical deflection of irregular bridge, the pier top should set the beams to enhance the bridge’s torsional resistance and bending resistance, which size should not be too small to cause every stringer uniform force, the right column diameter and section type will be beneficial to the torsional resistance of invisible cap and the internal force of pier.3、By comparing the finite element simulation results with load test, measure date like strain and vertical deflection is less than theoretical value, and is identical with theoretical value. When exerting load on the invisible beam, measure date of strain distribution can accurately force distribution of theoretical invisible beam under the action of vehicular load. Pier stiffness of single column is large, under the action of road-Ⅰ level, longitudinal and transverse morph is smaller."Bending-Torsion" coupling behave obvious exists in curved ramp bridge. Whether under the actions of central symmetric loading or eccentric loading, strain and vertical deflection in side webs are larger than endosternum and under eccentric loading this trend is more obvious. So, grillage theory is a practical method for accurate simulation of irregular bridge.