Papers by Keyword: Shear Lag Effect

Abstract: There are few studies about the shear lag effect and the effective flange width of the PC (Prestressed Concrete) box girder bridge with corrugated steel webs throughout the world in current time. In the present paper, based on the three-dimensional finite element analysis for a long-span continuous PC box girder bridge with corrugated steel webs and the corresponding conventional box girder bridge with concrete webs, a comparative study on the shear lag effect under vertical loads are carryied out together with the analyslis on the coefficient of the effective flange width. The results show that in the PC box girder with corrugated steel webs, the transverse distributions of longitudinal normal stress on the section of the slabs are obviousely non-uniform and they are different with those in the conventional PC box girder with concrete webs. And moreover, the shear lag effects in top slab of the PC box girder with corrugated steel webs are almost less obvious than those of the conventional PC box girder with concrete webs. However, the shear lag effects in bottom slab of the PC box girder with corrugated steel webs are almost similar to those of the conventional PC box girder with concrete webs, no matter what kind of vertical bending moment the cross section is subjected to

Abstract: In the present paper, based on the three-dimensional finite element analysis for a three-span continuous PC box girder bridge with corrugated steel webs and the corresponding conventional box girder bridge with concrete webs, a comparative study on the shear lag effect under self-weight is carryied out together with the analyslis on the coefficient of the effective flange width. The results show that At the sections in the negative bending moment near the intermediate piers, the shear lag effect in the bridge with corrugated steel webs is more obvious than that in the bridge with concrete webs by 8%; and the corresponding effective flange width coefficient in the bridge with corrugated steel webs is even smaller than 0.9, so the shear lag effect at these sections should be considered in the design of this type of bridges. At the mid-span section of the middle span of a three-span continuous bridge either with corrugated steel webs or concrete webs, the shear lag effect can be omitted since the corresponding effective flange width coefficient there is close to 1.0.

Abstract: Skewly supported continuous box girders have special mechanical properties compared with common continuous box girders. Skew coefficient for stress of skewly supported three-span continuous box girder is introduced to reflect the decrease degree of the normal stresses at the cross section of the middle span of the box girder. The finite element models of the skewly supported three-span continuous box girders with different skew angles are established by applying the SHELL63 shell element in software ANSYS. The variation of the skew coefficient for stress at different calculation points of middle span cross section under concentrated load is analyzed and the corresponding influence law is revealed. Research results show that the skew coefficient for stress of top slab is different from that of bottom slab at the cross section of the skewly supported three-span continuous box girder. The skew coefficient for stress of top slab is smaller than that of bottom slab. Skew coefficient for stress decreases with the increasing of the skew angle. Because of the shear lag effect, the minimal skew coefficient for stress of flanges occurs at the free tip of cantilever slab while the maximal skew coefficient occurs at the intersection of web and flange slabs.

Abstract: Based on the principle of minimum potential energy, choosing warping displacement function of parabolic displacement mode, using energy variational method to deduce Box beam shear lag effect analysis of differential equation to obtain shear lag warping stress. Through the calculation of simply supported box girder model and the analyse of the stress of Wide cantilever plate, box girder roof and box girder floor Assume a new warping displacement function. Through the analysis of measured results proved the rationality of this article assumes and research value.

Abstract: The hybrid girder cable-stayed bridge of railway has been applied in the design of the Yongjiang Bridge, it is first used in our country as yet. The mechanical performance of the steel-concrete joint as the key position of the hybrid girder cable-stayed bridge determine its safety and durability. Based on the background of a bridge in Zhejiang Province , the spatial finite-element model of model and actual bridge is developed to study the mechanical performance and verify the feasibility of design method of the model. As it turned out, the model can better reflect the stress of actual bridge. The trend of the stress of the key plates of its is basically identical. The steel-concrete joint can perfectly accomplish the transmission of the stress function. Bearing plate plays a vital role in the stress transfer, the function of the PBL shear connector near the bearing plate is obvious.

Abstract: The shear lag effect will cause damage to the curved box girders. And it will adversely affect the bridge’s seismic performance. In order to analyze the effect under seismic loads, finite element models were created in this paper. By changing the parameters, such as curvature radius, width and height, their influence on the shear lag were studied. Results show that the effect was more obvious in wide and flat box girders under seismic load.

Abstract: Shear lag effect of box girders under static, transient dynamic load and harmonic dynamic load has been studied, respectively, through finite element method. Shear lag effects under different load conditions were compared and dynamic loading influence on shear lag was analyzed. The results show that the dynamic load has great influence on shear lag of thin box girder that can not be neglected. During the research, the eyesight was transfer from the conventional static load to the dynamic load to study the shear lag problem of box girder. The research conclusions will be useful for the design and construction of bridges and will enrich the design theory of box girder.

Abstract: Through simulating box girder with shell element, the influence of the top flangebottom flange and web thickness on the shear lag effect of box girder used in cable-stayed bridge was discussed on the background of Jianning bridge in Zhuzhou. Parameter analysis of the thickness change of the top flange, bottom flange and web on shear lag effect of box girder was based on analyzing and comparing the calculated results. The results show that the thickness change of the top flange, bottom flange and web have more influence on the shear lag effect of top flange than that of bottom flange; thickness increase of bottom flange and web can make the shear lag effect intensified obviously; and thickness change of web has the most significant influence on the shear lag effect among them for box girder with single box and three rooms used in cable-stayed bridges.

Abstract: Prestressed concrete hollow retaining pile in lateral force resistance can effectively increase the bending height because of their hollow, so it can play a good effect in the pit maintenance .We will research and explore some problems about the innovative structure ,such as the suitable value of tension control stress , reasonable calculation method for flexural bearing capacity, shear lag effect causing by the hollow and using finite element analysis to verify. Do some preliminary research on some basic properties of the structure and lay the foundation for follow-up studies.

Abstract: In order to study the influencing parameters of the shear lag effects on the box-girder beam, the effective width was analyzed by the ways of looking up the present code and formula. Taking the simply supported and cantilever girder as the example, the parameter sensitivity was studied, such as width/span, cantilever length and span. The results showed that the shear lag effect of mid-span beam is small but the support beam is outstanding; the fixed amount relationship of the parameters and the shear lag effects was put forward. The conclusions will be useful for the design and construction of the box girder bridge.