Experimental Research and Analysis of the Shear Lag Effect of a Cantilever Concrete Box Girder under Double-Deck Uniform Loads

Abstract

The shear lag effect distribution, law of a single-box, three-room cantilever box girder under double-deck uniform loads is discussed through experimental research and analysis of the flexural behavior within the girder. Results show that with different load cases used, the cantilever roots generate a positive shear lag effect, whereas the half cantilever generates a negative shear lag effect. The distance of the positive and negative shear lag critical points from the cantilever roots is 18% to 23% of the cantilever length. The shear lag effect is most obvious under the roof uniform load in which the distance of the positive and negative shear lag critical points from the cantilever roots is the shortest. The same effect is less obvious under the double-deck uniform load, and it is least obvious under the floor uniform load. The bending structure of a double-deck traffic concrete cantilever box girder should be designed in accordance with the shear lag effect under roof loads to ensure safety.