Research On Shear-Lag Effect In Twin-Cell PC Combined Box-Girder With Corrugated Steel Webs

Corrugated-steel-web box girder bridge is a new type of composite structure bridge. It is capable of excellent mechanical properties and high economic benefits. In the medium and small span bridge, it is a very good choice. Its mechanical properties, nevertheless, haven’t been fully addressed. The study mainly focuses on the shear-lag-effect of the single-box twin-cell, corrugated-steel-web box girder.Based on a prestressed concrete continuous rigid frame bridge with corrugated steel webs and with 45+90+45m span, a MIDAS/CIVIL and ANSYS 3D spatial finite element models is established.The thesis elaborated the historical origin of the bridge with corrugated steel webs appear. The composition form of its cross section, Development and construction of domestic and foreign countries, Research status of its shear-lag-effectThe concept for the shear-lag-effect is provided, followed by definition of effective width of box girder; the classical theory, some previous studies and their deficiencies for the shear-lag-effect are generalized.The finite element analysis is introduced. Then based on the numerical software MIDAS/CIVIL and ANSYS, the full bridge model analysis for Enyang-River Bridge is specifically used to develop a new way to further study. Accordingly, the step-by-step analysis for this model is especially demonstrated. According to the mutual comparison between displacement from model in MIDAS/CIVIL with that in ANSYS, the model is validated.The shear-lag-effect of single-box, twin-cell, and corrugated-steel-web cantilever box girder under different load combinations is discussed. And the distribution of shear lag coefficient of corrugated-steel-web rigid frame bridge under live load or eccentric load is analyzed.It has been concluded that the shear-lag-effect of single-box, twin-cell, and corrugated-steel-web girder is only highly influenced by width-span ratios, height-width ratios, and boundaries, but little influence by suspended-wing ratios, wave heights, the number of transverse partition slabs, beam heights, and the supported paddle’s lengths.Through the investigation on the performance of corrugated-steel-web box girder models, the shear-lag-effect distributed property is fundamentally derived. Finally, a solid foundation for further bridge design and study has been laid.