محمود عدالتی

Concrete is a semi-brittle material (with viscoelasticity) that has two modulus of elasticity: static and dynamic modulus of elasticity. Concrete is also affected by its other mechanical properties, which include compressive strength (which is related to the type of cement, aggregate size, amount of water to cement and other additives), tensile strength of concrete, Poisson's ratio, creep and shrinkage. Concrete is affected by these factors due to the existence of the elasticity coefficient, which indicates the hardness and resistance of the material against deformation. Also, the dynamic modulus of elasticity is dependent on the stress-strain ratio in vibration conditions that affect concrete structures. In this thesis, the dynamic properties of three frames and one multi-story frame, which include horizontal stiffness (Keff), dissipated energy (WD) and damping ratio (βeq) under the influence of periodic load in static state, have been studied. These frames were exposed to an effective earthquake using ABAQUS software, as a result of which the main outputs such as shear forces, horizontal displacement and simulation between these frames have been obtained. The results obtained for all three models are: three values of horizontal stiffness, three values of energy dissipation and three values of damping ratio. These frames have been calculated once with static elasticity modulus and again with dynamic elasticity modulus. For these frames, the error rate for horizontal stiffness (Keff) is between (1.2-11)%, energy dissipation (WD) is between (5.3-13.6)% and damping rate (βeq) is between (0.9-5.3)% during use. It is calculated from the coefficient of static elasticity in the ABAQUS program. On the other hand, the error rate for horizontal stiffness (Keff) between (2.8-7.2)% and for energy dissipation (WD) between (3.6-9.7)% and damping rate (βeq) between (0.75-4.5)% when using calculated from the dynamic modulus of elasticity.