Project 2

Project 2: Rural Electricity Authority Building, is located in Abbasia Square, Cairo government, Egypt. It is governmental administrative building(See to below image), it was constructed at 1974. The building was previously designed according to The Egyptian Guidelines of Design and Conditions for Implementing Reinforced Concrete Works in Buildings, 1969. The building consists of 11 floors; ground, mezzanine, & eight typical floors. The structural system of the building was skeleton consists of deep isolated footings, concrete columns, beams & solid slabs. The client requested to evaluate the overall structural safety of the building and submitting the suitable design of repair, retrofitting and strengthening methods if required. - One of the most dangerous cases in need is a careful evaluation given that it is a governmental administrative building and a large number of employees and clients visit it daily and it is located in a large public square in the central of Cairo. - In this project, I followed the guidelines in the ACI 562-16 code (Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures and Commentary). - I performed visual inspection & destructive & non-destructive testing (core test & Schmidt Hammer test), I noticed spreading of vertical cracks due to corrosion of reinforcement in most of columns on the ground floor. Besides, low concrete compressive strengths of the extracted core samples (from selected columns located in various story levels) were observed. - Also, I performed the cement content test, chloride content, sulfate content & carbonation test for hardened concrete. I discovered that the cause of steel corrosion due to the carbonation effect. - I performed the structural analysis of the structure under gravity loads only (dead & live loads) and I checked the capacity of the columns for gravity loads resistance according to ECP ▒▒▒▒▒▒▒▒ and ECP ▒▒▒▒▒▒▒▒. All columns in all stories were unsafe under gravity loads, this due to lower compressive strength of the concrete. Csi Etabs software was used to show the actual straining actions in the columns under vertical gravity loads. Analytical model is shown in below image. - I performed seismic (response spectrum) analysis according to ECP ▒▒▒▒▒▒▒▒. I used Csi Etabs software also for seismic analysis. The structure was completely unsafe (All columns in all stories were unsafe, inter-story drifts & story displacements recorded higher values under lateral seismic loading exceeded the maximum permissible limits according to ECP-▒▒▒▒▒▒▒▒). - I have taken a bold and effective decision; I suggested to the client two proposals to solve this problem and he should choose one of them, and they were: - First Proposal (Strengthening of the building): To strengthen the building and protects the individuals in it and those who frequent it daily. It is necessary to remove of five upper floors of the building with the addition of E-shape concrete core in the middle of the building and four shear walls to resist lateral loads and improve the behavior of the building. Besides, strengthening of unsafe columns. I designed the retrofitting works as shown in the attached calculation sheets and below drawings. - Second Proposal: Demolition of the building and reconstructed it: In the event that the cost of repair and retrofitting work is high and is not economically feasible, I recommended to completely demolish of building with its foundations and rebuilding it.