Oral Presentation

Volume Title: ICCE2021 Vol. 2

¹Amr Abo Bakr Nassr; ²Hamdy H. A. Abd-el-Rahim; ²Fayez Kaiser Abdelsayed; ³Abd El-hady Gamal El-sokkary

¹Faculty of Stainable Design Engineering, Universities of Canada, New Administrative Capital, Cairo, Egypt

²Department of Civil engineering, Faculty of Engineering, Assiut university, Assiut, Egypt

³Department of Civil Engineering, Faculty of Engineering, Assuit University, Assuit, Egypt

Curved box girders exhibit complex torsional and distortional warping forces due to its curvature. The distortional forces cause the girder cross-section to deform. Consequently, internal diaphragms are installed to limit the cross-section distortion and distortional stresses. The commonly used diaphragm shapes included solid plate diaphragms and trussed diaphragms such as X- and V-shaped diaphragms. Finite element models were constructed to determine the effect of the diaphragm rigidity on the induced stresses and deformations in the girder. The diaphragm rigidity influenced the developed distortional warping normal stress in the girder; however, that effect diminished the more rigid the diaphragms became. The solid plate diaphragms were topologically optimized to produce more efficient shapes for less material used. The studied parameters were cross-section aspect ratio, and diaphragm spacing, since they were found to have a large effect on the distortional warping forces. The various optimized topologies followed a predictable pattern depending on the aspect ratio. The traditional diaphragm shapes were compared with the topologically optimized diaphragms where the total mass of material used was the same for the optimized diaphragms, X- and V-shaped diaphragms. The V-shaped diaphragms developed the largest deformations for all recorded cases. The solid plate diaphragms showed the lowest distortional warping angle in the girder despite the number of diaphragms; however, it had the largest distortional warping stress for low diaphragm number. The topologically optimized diaphragms and X-shaped diaphragms had similar results that balanced between stress and deformation. The developed von-mises stress within the topologically optimized diaphragms was the least when compared with V-/X-shaped diaphragms.

Box; bridges; curved; distortion; Optimization; topology; diaphragm