Behavior Of Thin Walled Channel Shaped Reinforced Concrete Columns Under Combined Biaxial Bending And Compression

Next to rectangular, circular and L shapes, Channel section may be the most frequently encountered reinforced concrete columns since they can be used as box wall for elevators. Nevertheless, information about the load deformation behavior is not generally available to structural engineers. Most of the investigations have been emphasized on the ultimate strength of column sections under combined biaxial bending and axial compression and the resulting interaction surface. No attention is paid to load deformation behavior. Current code provisions do not provide adequate guidelines for assessing the strength and ductility of biaxially-loaded reinforced concrete columns. Therefore, this investigation is aimed at an experimental and analytical study of the behavior of biaxially-loaded channel- shaped short columns as the applied load is increased monotonically from zero to failure. For the test purpose four reinforced concrete Channel shaped columns of nearly half the size of the true specimens were casted and tested till failure. Moment-Curvature and Load Deflection curves obtained from testing channel section were compared with the results from a computer program developed by Hsu1 and were found to be in excellent agreement. In addition a computer program was developed to calculate the ultimate flexural capacity of cracked arbitrary concrete sections under axial load and biaxial bending based on the Brondum-Nielsen s paper.