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Design Assessment Of A Reinforce Concrete Building Through Non-Linear Analysis May 2013 Geometry of the RC Building An additional action, in order to redesign the frame, was to include beams. As seen in Fig.8, the beams that were added had a section size of 35x70 cm except the parimetric beams that had a 20x25 cm section which was not modified according to the initial design. Numerical results derived from the pushover curve: Fig.2 Ground floor plan view. Fig.4 Pushover curve of the frame. Fig.1 Section View of the RC building. Fig.3 Typical floor plan view. Abstract: Given the recent earthquake activity in the UAE, seismic excitation and the dynamic behavior of our structure became a very popular subject. As it is known our structures are being designed according to certain code provisions, which do not force the accounting of significant seismic loads given that UAE is considered to be a non-seismically active country. This Thesis will study the design of a reinforced concrete (RC) building that was designed by accounting low seismic loads and considers a flat slab framing system. The main objective of this work is to determine whether the structure is capable of carrying a medium seismic excitation according to Euro code, through the use of push over analysis. To achieve this goal finite element models are constructed in Etabs and Sap 2000 commercial software through which the seismic assessment of the under RC structure is performed. Fig.5 Deformed shape and plastic hinges prior to failure. Fig.6 Additional Shear walls. As shown in Fig.9, after the redesign was completed and the pushover analysis was re-executed, the new push over curve of the building revealed that the carrying capacity of the frame was increased. The computed carrying capacity of the redesigned frame was 22688.135kN. Which satisfies the demand of the seismic code. Fig.9 Pushover curve of the redesigned frame. Redesign: Conclusions: As seen in Fig.6, an additional row of 35X300 cm shear walls were added to the front and back of the building. These shear walls extend from the ground to the top roof. In case of a seismic excitation the shear walls will resist to the horizontal loads thus will increase the structures carrying capacity. 1. Assessing our structures by using software such as ETABS and SAP2000, is of significant importance in terms of safety and accuracy. ETABS and SAP2000 automatically generate and assign code-based loading conditions for gravity, seismic, wind, and thermal forces thus performing the design and assessment becomes a very efficient procedure. 2. Our numerical results and overall experience showed that modeling RC structures is a procedure that requires both theoretical knowledge and practical experience. 3. After performing a modal analysis it was found that the 1st mode was rotational thus the geometry of the frame and the stiffness distribution of the shear walls were irregular. In addition to that, we found that the 1st fundamental period was equal to 1.83 seconds that underlines the fact that the flat slab system used derived a flexible mechanical behavior despite the use of relatively large shear walls. 4. The 12-storey RC building was found inadequate in carrying the 22.62MN seismic load according to EC8 according to the numerical results that derived from the non-linear analysis. For this reason a redesign of the frame was performed so as to overcome this issue. Fig .7 columns to shear walls. Mohammed Mohideen 200710322 Fig.8 Beams used throughout RC frames. Plastic hinges were assumed along the whole structure so as to account material nonlinearities in both beam and shell elements. It is important to note here that the results derived in the previous sections were through the use of Etabs software. The pushover analysis was performed in SAP2000. Fig.5 shows the developed plastic hinges prior to failure. As seen in Fig.7, a closer view is given to show the exact location where three columns located at the ground floor and mezzanine were also converted into shear walls so as to increase the stiffness of these floors. The main objectives were: • Study the mechanical behavior of the RC structure • Preform Pushover analysis • Redesign the building so as to achieve a seismically resistant behavior Software used: Etabs is a structural and earthquake engineering software produced for the analysis and design of multi-story buildings. Sap2000 is integrated software for structural analysis and design it harnesses an analytical method. The reason two software's were used was because problems were faced with shell elements regarding Etabs As we can see from Fig.4, the first plastic hinges occur for a total horizontal load of 5.1 MN and the maximum current capacity of our structure was found to be 17 MN with a total displacement of 6.1 cm at the top floor. The seismic demand according to Ec8 was 22.6 MN thus the structure requires to redesigned. Presented by: Adnan Mayassi Moiad Jumaa 200910018 200710497 Supervised by: Dr. George Markou Ahmad Khier 201010540