The Influence Of Torsional Properties Of Diaphragm Plate On The Box Girder With Corrugated Steel Webs

PC box girder with corrugated steel webs has a great deal of advantages, such as light self-weight, clear force, high effective prestres, short construetion period, appearance, recycling and reusing. But its torsional properties is insufficient. Engineering mostly adopts the diaphragms to improve the torsional properties. In this paper, the effect of diaphragm on the torsional properties was studied from the view of engineering practice. The main research results are as follows:(1) The test models of box girder with corrugated steel webs is designed and tested, and selected reasonable unit type and material properties of ANSYS finite element simulation. The results showe that the ANSYS finite element model calculation results and the test beam experimental data analysis results are in agreement with each other.And it proves that,the modeling process of steel web plate connected to the top, bottom rigid connection is feasible, and the ANSYS model is correct.(2) Box girder’s torsion is obvious under partial load without diaphragm plate, the torsional performance is poorer. Add diaphragm plate can improve the torsion stiffness, but also to control the warping stress of concrete and steel web plate shear stress is favorable.(3) Increase the number of diaphragm is improved to a certain extent the torsional behavior of box beam, when the diaphragm reaches a certain number, box beam torsion performance increase slowly reduced. The diaphragm has great effect on the height span ratio corrugated steel web box girder is larger, less impact on the high span relatively small box girder. Suggestions of box girder with corrugated steel webs as far as possible in the design of height to span ratio of 1/14 to 1/9. When the high-span ratio greater than 1/9, it is recommended the crossbeam arranged as 1, greater than 1/14 when the span ratio is less than 1/9, the proposed amount of the crossbeam arranged as 3, when a high-span ratio is less than 1/14 recommendation arranged transverse bulkheads number 5.(4) Thick diaphragm can reduce the distortion of box girder and increases the torsional properties. Diaphragms together than the scattered layout increase more favorable of torsional properties on box girder with corrugated steel webs under reversal.It is suggest that diaphragm plate thickness design for a corrugated plate length. Use steel to replace the concrete design of diaphragm is helpful to improve the torsional property of box girder. The proposed design of box girder with corrugated steel webs, the weight of the diaphragm plate to replace, so take up less space, also can reduce the complex process of cast-in-place diaphragms.(5) Increasing the number of diaphragm is not obvious to improve of the flexural behavior of continuous box girder with corrugated steel webs, but it has been improved to torsional properties. After continuous box girder with concentrated load or eccentric load line in the eccentric arrangement of a diaphragm, The offset load deflection is reduced less after arrangement of a diaphragm under continuous box girder with concentrated load or eccentric load line in the eccentric. The continuous box girder height to span ratio of 1/7 is suggested set to 1 diaphragm, the diaphragm spacing is 1/2L. In The maximum shear stress appears in the section near the 3/4L under the eccentric and concentrated load, instead of loading section near 1/2L.