Author : N. Z. Hassan, S. K. Elwan, M. M. Yehia and W. M. Shaaban

This research presents an experimental and finite element modeling investigation for the combined frames having reinforced concrete column connected to L-Shaped steel frame. Eight frames tested under constant vertical and variable lateral load up to failure. All frames had the same dimensions and classified into three groups. First group consist of two control frames (CC) and (SS) designed to carry the same lateral load. The second group includes testing of three combined frames (SC 1), (SC 0.5), and (SC 2) with different ratios of stiffness between steel beam and steel column (ksb/Ksc = 0.94, 0.5, 0.25) respectively. The third group includes testing of three combined frames (CS 1), (CS 0.5) and (CS 2) with the same dimensions in the second group, but changing lateral load direction. Frames SC1 and CS1 have the same cross section dimensions of steel beam, steel column and concrete column in control frames. Results indicates that lateral failure of the control concrete and steel frames were approximately equal but the horizontal displacement of concrete frame is about 31.74% compared to that of steel frame. Lateral failure load decreased by 34.7% for combined frame SC1, while horizontal displacement increased by 136% compared to concrete frame (CC) and decreased by 25% compared to steel frame (SS). Lateral failure load decreased by 37% for combined concrete – steel frame CS1, while horizontal displacement increased by 57% compared to concrete frame (CC) and decreased by 50% compared to steel frame (SS) since the concrete column absorbs most of lateral load and decreases horizontal displacement. The change in the relative stiffness between steel beam and steel column in frames does not influence lateral load capacity but affects the horizontal displacement. Three-dimensional finite element models created by using ANSYS program to simulate the behavior of the tested specimens. In addition, study of different parameters such as relative stiffness between steel beam and concrete column while change the relative stiffness between steel beam and steel column were investigated.

Keywords: Concrete frames, Steel frames, Combined frames, Lateral Load.

Article published in International Journal of Current Engineering and Technology, Vol.8, No.5 (Sept/Oct 2018)