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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. [ABSTRACT FROM AUTHOR]

This paper presents the efficiency of using prefabricated ultra‐high performance fiber reinforced concrete (UHPFRC) plates in shear strengthening of reinforced concrete (RC) beams experimentally and numerically using finite element method. In order to ensure high quality and facilitate the strengthening process on site applications, it has been considered to apply UHPFRC as a plate pasted on concrete surface using epoxy. Tested specimens included four strengthened beams besides three control beams. Strengthening the RC beams was based on the use of two different techniques; (a) one longitudinal side strengthening (b) two longitudinal sides strengthening. Moreover, strengthening RC beams with reinforced or non‐reinforced prefabricated UHPFRC plates was also investigated. Results show that UHPFRC plates significantly increased the maximum load capacity, ductility and mid span reinforcement strain of the strengthened RC beams comparing with reference beam failed in shear. Also, steel connectors used in reinforcement of UHPFRC plates prevented debonding failure mode. A three‐dimensional (3D) finite element model (FEM) of the tested beams was also developed to predict the behavior of these specimens strengthened in shear. The adhesive layer was simulated using cohesive surface model to consider the slippage between concrete surface and UHPFRC plates. Results of the FEM showed good agreement with experimental results, as they were able to predict the behavior of the beams with high accuracy. [ABSTRACT FROM AUTHOR]

• FE modeling of jacketed columns captured the experimental response reasonably well. • Using adequate number of dowels led to a monolithic behavior of jacketed columns. • An analytical model was proposed to draw the interaction envelop of jacketed columns. This paper describes the development of finite-element (FE) and analytical models for investigating the behavior of reinforced concrete (RC) columns strengthened with UHPFRC jackets under axial or eccentric loading. The main goal of both types of models is to produce load-moment (N - M) interaction envelope for RC columns strengthened with UHPFRC jackets. In the FE model, a methodology to implement bond-slip model between core concrete-to-jacket concrete is presented. The interface is implemented using connector elements. The FE results were verified versus experimental results of other researches, showing high accuracy in relation to load-deformation, ultimate load capacity, and failure modes. Using the verified FE model, a parametric study on strengthened columns with UHPFRC jackets is carried out. Several parameters, including interfacial shear strength, UHPFRC jackets' thickness and number of dowels, are investigated. The results show that a monolithic behavior of strengthened columns can be attained by increasing the core surface texture, decreasing the jackets' thicknesses, and using adequate number of dowels. A new analytical model is proposed to generate the load-moment (N-M) interaction envelope of strengthened columns with UHPFRC jackets. A comparison between proposed analytical model and FE results in addition to experimental data available in the literature confirmed the accuracy and validity of the proposed analytical model. [ABSTRACT FROM AUTHOR]