Research On Shear-lag Effect In Combined Box-girder With Corrugated Steel Webs

Prestressed concrete box girder is one of the most popular structure of modern br-idge, but it has some disadvantages. Composite box girder with corrugated steel is anew kind of slight structure, whose slab is corrugated steel webs and the top and bott-om slabs are made by concrete. The top and bottom slabs bear almost all the bending moment, and the webs bear the most of the shear force. This kind of girder conquers many disadvantages of the prestressed box girder, it has vast application prospects.This paper refers to the results obtained by other people, analysis the shear-lag effect in the simple-supported box-girder with corrugated steel webs. The main works carried out are as follows:(1) In the first chapter, this paper instructs the generation and development thecharacters in structure and mechanics, the advantages and the disadvantage of the composite box girder with corrugated steel slab. It also instructs the ac-tuality of the study to shear-lag effect in and abroad. This chapter tells the matters this paper studies.(2) In the second chapter, this paper firstly does theoretical analysis to the modelgirder by energy variational method, then gets the computational formula to shear-lageffect coefficient. Then it analysis the model girder by finite element method, and compare the result to that gets by the variational method. Through the comparison, it tells that the method to found the model is right. It also calculates the transverse and lengthwise shear-lag effect of the model, wh-en it under different load and constraint conditions. It compares the shear-lag effect rule of the composite box girder with corrugated steel slab to the other girders with different slabs, draw the rule of the shear-lageffect of the composite box girder with corrugated steel slab.(3) In the third chapter, this paper analysis the influences produce by the g-eometric parameters, such as width-span ratio, width-hight ratio, angle of inclination of theslab, the hight og the wave of the slab. It tells that, the influnce produced by thewidth-span ratio is very notable, and the influence produced by other geometric parameters is very small. (4) In the third chapter, this paper induces main influencing factors for th-e shear-lag effect, getting conclusion of the effective width coefficient for the composite box girder with corrugated steel webs for reference, and then com-pare the conclusionwith the coefficient of box beam as specified in the spec-ification, getting the law ofinfluence.