Construction and Steel Structure

Biography

Biography: Ayman M. Okeil

Abstract

Structural engineers are often involved in projects to strengthen deficient structures as a feasible alternative to cost-prohibitive full replacement of the structure. The use of composite materials to strengthen existing concrete structures by externally bonding thin laminates or strips is mature enough that design codes and guidelines are available for flexural, shear, and axial strengthening applications. Researchers have also investigated strengthening steel structures using composite material, however, the field is not as mature as it is for concrete applications. This paper presents a new strengthening technique where pultruded GFRP sections are bonded to shear deficient regions to enhance the local buckling resistance of the thin walled steel structures. The technique, referred to as Strengthening-By-Stiffening or SBS, was developed at Louisiana State University. An experimental program was designed to study the effect of FRP stiffener configuration on the efficiency of SBS. Different orientations, web slenderness values and aspect ratios were tested monotonically up to failure. The ultimate shear capacities beams were enhanced by a minimum of 30% when one stiffener was used on a beam with a square panel and a maximum of 56%. Post yielding behavior including the transition from a tension field to sway-frame load path will also be discussed.