Deflection of composite cellular beams

Abstract

The deflection of composite (cellular) beams is important for serviceability purposes. However, the available methods to predict the deflection are inaccurate. This research aims to propose a method for predicting the deflection with improved accuracy. The proposed deflection consists of contributions from overall flexural behavior and Vierendeel bending. In addition to the slip action, a reduction factor for computing the effective moment of inertia is investigated and used to compute the flexural deflection. The Vierendeel deformation was determined based on shear deflection of a virtual cantilever beam. No local composite action is conservatively assumed in the cantilever beam. Over 700 three-dimensional finite element (FE) models were simulated to investigate the reduction factor and limitations of the proposed method. The FE model was validated against 13 experimental load-deflection curves from the literature. The proposed method is suitable for predicting the deflection of composite cellular beams having the spacing ratio 1.35 or higher and the span ratio higher than 5. For such cases, the deflection estimate is from 0.90 to 1.05 times the FE deflection. The web-post deformation and the global shear deflection affect the prediction accuracy. In comparison to other methods, the proposed method is more accurate in predicting the deflection.