Sharif Digital Repository

Concrete has long been considered by engineers as one of the most used constructional materials. Therefore, recognition of mechanical behavior of concrete materials is of particular importance. So, extensive studies have been undertaken to understand and analyze its behavior under different loading conditions. Based on these studies, many models for describing the behavior of concrete are presented. Of these, many models are based on the combination of plastic theory and damage mechanics, and by using them, significant success has been achieved in the correct modeling of concrete materials. On the other hand, one of the important loading conditions encountered by concrete structures is in... 

The understanding of the mechanical behavior of engineering materials and their interfaces plays an important role in the prediction, analysis, and desing of engineering systems. Considering the important role of understanding and describing the behavior of materials and systems, this thesis is devided into three sections: 1) Modeling the behavior of polymer concrete under uniaxial compression, 2) Modeling the behavior of various light- and normal- weight concretes under uniaxial and triaxial compression, and 3) Modeling the behaivor of interfaces between polymer concrete and normal concrete with sand. In this context, various constitutive models were investigated and compared together,... 

Normal aggregates are replaced by polystyrene beads (EPS) due to their low unit weight. EPS concrete is known for its low density and environmentally friendly properties apart from having various pros such as better heat and sound isolation, affordability, and ease of construction. EPS grain size can also affect the compressive strength, and the tensile strength of EPS concrete compression is also inversely related to EPS grain diameter. The EPS concrete has four different percentages of EPS; 0%, 25%, 50%, and 75%. Each EPS percentage has six different unit weights; 15,20,25,30,35 and 40 kg/m3. In the present study 19 different types of mixing designs were used, the one with no EPS beads has... 

The investigation of non-prestressed concrete components subjected to impact loadings has been reported in the literature. However, the knowledge on the impact-resistant capacity of pre-stressed concrete components is very limited. In this study, behavior of pre-stressed concrete slabs strengthened by FRP sheets is investigated. The behavior of strengthened pre-stressed concrete slabs under impact load is analyzed using finite elements method. The effects of FRP strengthening of pre-stressed concrete slabs to resist impact loads have been studied using ANSYS software. Pre-stressed concrete slabs have been modeled without/with different FRP strengthening measures. Pre-stressed concrete slab... 

Precise numerical models to predict responses and damage of FRP strengthened RC slabs to impact loads are limited in the literature. The behavior of (RC) slabs strengthened by FRP sheets is investigated. The behavior of strengthened RC slabs under impact load is analyzed using finite elements method. In this study, the effects of FRP strengthening of RC slabs to resist impact loads have been performed using ANSYS software. RC slabs without/with different FRP strengthening measures have been simulated in this study. RC slab without strengthening and RC slab strengthened with FRP sheets applied to the tension face of the slab have been included in the model. Each slab is subjected to repeated... 

Although considerable researches have been conducted on strengthening RC structures using FRP method during past years, a few researches have been reported on RC arch or curved structures strengthened by FRP. In this study, behavior of RC arches strengthened by FRP strips is investigated. The behavior of strengthened RC arches under gravitational load is analyzed using finite elements method. The arches are modeled by appropriate software in order to evaluate the behavior. The structural behavior of arches is more complicated. So, the estimation of the effect of strengthening using FRP technique on such structures is hard in comparison with traditional RC beams. In this study, the effect of...