• Journal of Korean Society of Steel Construction
• /
• v.19 no.6
• /
• pp.559-573
• /
• 2007

Orthotropic steel decks are manufactured by welding thin plates therefore it is inevitable that there are abundant works of welding process. On connection of transverse rib web, crossing point of longitudinal rib, transverse rib and deck plate and cut-out parts of transverse rib are the significant position of stress concentration because of out of plane and oil-canning deformation caused by longitudinal rib distortion with shear force and distortion. At the current research, the crossing point where the orthotropic steel decks's effect of improving fatigue performance are high, not placing scallop and diaphragm which have same plane with transverse rib placed inside of longitudinal rib at the same time, the reduce effects of stress concentration at the cut-out section and the crossing are high. Especially the installation of the diaphragm causing great effects based on research results to stress concentration appearance reduce effects at the cut-out section, putting radius of curvature of the diaphragm's top and bottom as a target, as a result of carrying out the parametric analysis an optimal diaphragm form that has great effects in fatigue performance came to a conclusion. Also based on optimal diaphragm form, an advantage of the diaphragm optimal setting position for improvement of the fatigue performance came to a conclusion.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.5
• /
• pp.597-606
• /
• 2006

Since FRP materials have various advantages over steel, many research activities to use them for the civil engineering applications are now in progress. The present paper deals with the local buckling behavior of FRP pultruded members as a first step toward the development of design criteria. In the design of compression members, it is very important to know not only if local buckling occurs or not but also which plate component governs local buckling, but it is not easy to perform this work in a rigorous manner. In the present paper, a simple and accurate equation which can compute the coefficients of buckling of orthotropic plates and local buckling of pultruded compression members is suggested by performing rigorous analysis, energy analysis, and parametric study. The local buckling strength and the plate component governing the local buckling behavior of thin-walled pultruded compression members can be easily determined by using the proposed equation.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.12 no.3
• /
• pp.1-15
• /
• 1992

A Practical and easily applicable methods for the numerical analysis and the optimum design of continuous and horizontally curved two-way slab systems with twelve possible edge conditions are presented. The proposed method for the numerical structural analysis is based on the use of design moment coefficients which are derived from the elastic theory of thin curved plates. The optimum values are selected from within the feasible region in the design space defined by the limit state requirements. The sequential linear programming is introduced as an analytical method of nonlinear optimization. The optimum design variables, including a effective depth and transformed steel ratios per unit width of middle and column strips of slabs, are then determined.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.2
• /
• pp.149-156
• /
• 2011

In this paper, a methodology is proposed to improve the stress prediction of plates via Saint Venant's principle. According to Saint Venant's principle, the stress resultants can be used to describe linear elastic problems. Many engineering problems have been analyzed by Euler-Bernoulli beam(E-B) and/or Kirchhoff-Love(K-L) plate models. These models are asymptotically correct, and therefore, their accuracy is mathematically guaranteed for thin plates or slender beams. By post-processing their solutions, one can improve the stresses and displacements via Saint Venant's principle. The improved in-plane and out-of-plane displacements are obtained by adding the perturbed deflection and integrating the transverse shear strains. The perturbed deflection is calculated by applying the equivalence of stress resultants before and after post-processing(or Saint Venant's principle). Accuracy and efficiency of the proposed methodology is verified by comparing the solutions obtained with the elasticity solutions for orthotropic beams.