الفهرس 
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Abstract
1:-Introduction: - Many researchers studied the effect of Soil Structure Interaction (SSI) on the behavior of reinforced concrete structures constructed from Normal Strength Concrete (NSC). For many years, High-Strength Concrete (HSC) was necessary in a few positions. The main advantages of using (HSC) is the cost saving from the use of smaller volumes of concrete, which results in reduced shuttering costs and lighter foundations, in addition to the saving in the area occupied by large columns. Using HSC in tall building frame structures and dual systems leads to smaller size of the reinforced concrete walls and columns in the lower stories, which is recommended by the Architects. This will result in a change in the lateral resistance of these structures when subjected to earthquake excitations. 2:- Research scope: - With the commercial availability of HSC having compressive strength approaching 140 MPa, it has become necessary to study the behavior of structures constructed from HSC under earthquake excitations. In this research seismic behavior of high strength reinforced concrete structures will be analyzed taking into account the effect of soil structure interaction. 3:- Research objective: The main objectives of this study are to compare the nonlinear seismic behavior of reinforced concrete frame buildings, dual systems and elevated tanks constructed from NSC (with characteristic cylinder compressive strength MPa) and from HSC with ( MPa) considering soil structure interaction. Investigating the effect of soil structure interaction on the straining actions of buildings such as base shear and over turning moments. Verifying the reliability of the criteria provided by the studied codes, to handle the effect of soil structure interaction in the seismic response of structures constructed from NSC and HSC. 4:- Steps Study: - Many cases of multi-story reinforced concrete moment resisting frames and other dual systems, constructed from NSC and HSC have been analyzed using OPENSEES program to investigate the effect of SSI on the seismic response of frames and dual systems constructed from NSC and from HSC. The analyzed 2-D frame has 12 stories while the analyzed 2-D dual systems have 12 and 9 stories. For high strength concrete frames and dual systems, two cases of section dimensions have been studied, The first one is high strength concrete frames and dual systems with NSC section dimensions and the second case is high strength concrete frames and dual systems with reduced section dimensions as the concrete strength increased. To investigate the effect of soil structure interactions on the seismic behavior of NSC and HSC, an elevated cylindrical tank supported on reinforced concrete shaft with capacity equal to 750 m3 and shaft height equal to 30 m above ground level has been analyzed. 5:- Summary of Study:- For 12-stories building frame, considering SSI using Wolf model with soft soil increases the story drift by 19.25%, 28.1% and 18.4% for NSC and HSC (reduced sections) and HSC (NSC sections), respectively, while for Gazetas model these ratios are 25.7%, 34.9%, and 21%, respectively. For 12-stories dual system, considering SSI using Wolf model with soft soil results in an increase in the drift by 40.5%, 25.2% and 31% for NSC and HSC (reduced sections) and HSC (NSC sections), respectively, while for Gazetas model these ratios are 45.6%, 29.5%, and 35.2%, respectively. The calculated maximum story drift considering SSI with soft soil S1 for 12-stories building frame constructed from HSC with fc’ = 75 MPa exceeds the story drift limit required by the international codes by 7.4%, 13.2% and 6.5% for Wolf, Gazetas and Egyptian Code of Practice (ECP) model, respectively. For 12-stories dual system the calculated maximum story drift is still under the limit of the international codes due to the large stiffness of the shear walls. The method of the Egyptian code ECP 201-2012 for elevated tanks design is more conservative because the base shear and base moments calculated using this method is about twice the base shear and the base moment calculated using dynamic analysis without SSI even with strong earthquake record as El-Centro record, hence the response reduction factor ”R” for elevated tanks supported by R.C. shaft found in the ECP201-2012 might be reviewed.