SHEAR LAG EFFECT STUDY OF A COMPOSITE GIRDER CABLE-STAYED BRIDGE DURING CONSTRUCTION.

To investigate the shear-lag effect in the main girder of a composite twin-box girder cable-stayed bridge during construction, a full-bridge model and a local spatial model were established using the finite element software MIDAS/Civil and ABAQUS, respectively, for the main span of the Chibi Yangtze River Bridge in Hubei Province, China, as an engineering example. On this basis, the shear-lag effect in the composite twin-box girder under multiple typical construction conditions was analysed through numerical simulation, and the accuracy of the model was verified by field measurements at the construction site. Results demonstrate that as the balanced cantilever construction progresses, the stress in the deck slabs near the junction of the anchor plate and the outer web of the side box girder and at the location of small longitudinal beams changes substantially. However, the stress at other girder sections is gradually uniformly distributed, the shear-lag coefficient tends to be stable, and a phenomenon of positive and negative shear-lag effect conversion occurs in the deck slab sections of the main girder. [ABSTRACT FROM AUTHOR]