This paper presents a finite element (FE) study of beam-column joints subjected to cyclic loading. This study is primarily dependent on investigating the shear behavior of joints under the influence of different column axial load ratios. Wherefore, a total range of the column axial load ratios, whether in tension or compression has been considered. This paper proposes a two-dimensional (2D) FE model that considers material non-linearity. The proposed FE model was verified with experimental results from literature that tested varying column axial load ratios and different failure modes. The examination among experiential and numerical outcomes demonstrated that the FE model can reenact the conduct of beam-column joints and can catch the different failure modes with acceptable accuracy. A parametric study was established using the proposed FE model and strut-and-tie (ST) model of Pauletta to assess the Eurocode joint shear strength equations. For this purpose, four specimens were designed according to Eurocode recommendations while two other specimens were designed to satisfy all of the Eurocode recommendations except for the required joint confinement. An interaction diagram was introduced for each specimen to express the behavior under varying column axial load ratios. The results of the comparison between Eurocode, FE model, and ST model showed some differences in calculating the joint shear strength capacity, especially under column tension loads. Furthermore, this paper proposed new design equations based on Eurocode equations taking into account the column axial load effect. These proposed equations worked to increase the accuracy in calculating the joint shear strength capacity. Proposed equations were compared to the FE model results and other experimental results available in the literature. The comparison showed that the differences with the FE model decreased and that the proposed equations had better accuracy at different tension and compression loads than the Eurocode.

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The outrigger system is an economical and effective solution to improve the seismic performance of high-rise buildings. Numerous studies have been carried out on the optimum position of the outrigger system. However, space availability is the main factor as potential locations of outriggers are typically limited to refuge and mechanical floors. This paper proposes some methods to reduce obstructed space at the outrigger level. Comparative studies were performed on A 40story core-wall building with conventional and proposed virtual outrigger in terms of lateral displacement, drift, base shear, base moment, core moment and fundamental natural period for different positions of the outrigger system. The building was subjected to eleven ground motions scaled to meet the expected peak ground acceleration in Cairo zone. This study concludes recommendations for proposed outrigger configurations which can give higher performance than conventional outrigger and extra free area can be obtained.