Beam-column joints play an important role in the overall resistance of reinforced concrete frames during seismic events. The Earthquakes of Al Asnam on October 10, 1980, and Boumerdes on May 21, 2003 in Algeria, have highlighted the failure of beam-column joints as a cause of building collapse. 3D nonlinear finite element analysis with ANSYS software has been used in order to examine exterior RC beam-column joints under monotonic loading. The research has investigated the influence of the value of the column-to-beam strength ratio (CBSR) of these joints on shear strength and seismic performance of concrete structures by changing the height and longitudinal reinforcement of the beam while keeping column dimensions constant. It has been shown that the beam-column depth ratio and the beam longitudinal reinforcement ratio have a significant effect on the shear capacity and seismic behaviour of exterior beam-column joints. An appropriate value of the flexural strength ratio between the column and beam is crucial in order to establish a "strong column-weak beam" mechanism in reinforced concrete frames, because inadequate values can lead to premature failure or reduced shear capacity at the junction. The Algerian seismic code – RPA99/version2003 suggests a minimum value of column-to-beam strength ratio equal to 1.25 at joints for seismic design when building codes in other countries call for higher ratios. Nevertheless, this approach might not accurately represent the actual behaviour and could constrain the optimal performance of structures.

This paper presents a numerical investigation on the flexural performance of a novel cementitious reinforced GEM-TECH material using finite element method. A discrete nonlinear FE model using the commercial software ANSYS was employed to model a steel-reinforced GEM-TECH beam. Element SOLID65 was used to model the cementitious material while LINK180 element was used to model the reinforcing bars and stirrups. For model validation, FEA results and crack plots were compared to those obtained from the experimental results of five reinforced GEM-TECH beams: three beams designed with target density of 1810 kg/m3 and two beams with target density of 1600 kg/m3. Both load-deflection plots and the failure mode crack plots predicted by the FE model were in good agreement with the experimental results.