Structural behaviour of steel cold-formed sigma beams strengthened with bonded steel tapes

摘要

In the paper the effectiveness of strengthening of thin-walled, cold-formed sigma beams using glued steel tapes is investigated. Special attention is paid to the evaluation of the possibility of increase the load capacity with simultaneous limitation of beams displacements by appropriate location of steel tapes on the sigma cross-section. The study is based on laboratory tests and numerical analysis results. The laboratory test were conducted on eight simply supported, single-span beams made of Sigma 200x70x2 profile by "Blachy Pruszynski". Two beams were reinforced with steel tape placed on the inside surface of the upper flange, two with steel tape glued on the inside surface of the web, two beams with reinforcement located on the inside surface of the bottom flange, and two beams were tested as reference beams without reinforcement. Steel tape with the width of 50 mm and thickness of 1.5 mm, made of steel 5235 was used as the reinforcement and was glued to the beams with SikaDu (R)-30 adhesive. Precise strain measurement was made using electrofusion strain gauges and displacements measurement was performed using two lenses of Aramis software with combination with the Tritop machine. Numerical models of the considered beams were developed in the program Abaqus. Work completes the comparative analysis and conclusions.