Improvement of axial load capacity of large rectangular columns using cfrp method - case study

Abstract

Columns are one of the most critical structural components of any structure. Column strengthening requirements are risen due to many reasons in relation to rehabilitation and improvements of existing buildings. Additional 4 floors were required to be added to a medium rise office building which was originally designed for 8 stories while it had been constructed up to its 4th floor. Detailed assessment of the structural capacity of the existing columns revealed that about 20% of axial load capacity improvement of selected ground floor columns was required to withstand the additional loads from the proposed additional floors. The strengthening of the existing columns was proposed to be done using carbon fiber reinforced polymer (CFRP). Preliminary CFRP design was carried out in accordance with the ACI.440.1R. The code’s limitations on the aspect ratio and the maximum face dimensions of columns had to be disregarded due to the shapes and dimensions of the real columns. Therefore, the proposed CFRP design was validated using a scale model column test and numerical model results obtained using ABAQUS. Selected columns of the building were strengthened using the proposed CFRP application and the building has been in operation for two years after successfully adding four new floors to it. This paper reports and discusses the outcomes of the case study on strengthening of different shape columns of this office building using CFRP.