ARCHITECTURAL AND STRUCTURAL DESIGN OF A BUILDING APARTMENT CASE STUDY OF GASABO GISOZI SECTOR

Abstract

This project, titled “Structural and Architectural Design of a G+3 Residential Apartment in Gisozi, Rwanda,” was undertaken as part of the requirements for obtaining an Advanced Diploma at ULK Polytechnic Institute. The project encompasses both architectural conception and structural design, with a strong emphasis on effective communication to all stakeholders. Each section of the project is clearly numbered to facilitate easy navigation, allowing users to quickly access specific areas of interest. The design process was informed by a wide range of references and follows the standards set out in various authoritative documents, particularly the British Standards (BS). The structural analysis began with the calculation of all expected loads, including the building’s self-weight. The architectural design includes detailed plans showing the dimensions and overall shape of the building. The structural design covers critical elements such as beams, slabs, columns, stairs, and foundations, adhering to the guidelines of BS 8110-1:1997. Detailed plans and reinforcement schedules for these elements are also provided. The total cost of the building is estimated at 281,433,500 Rwf. The design criteria are primarily based on British Standards. Structural Design Details: 1. Slab Design: • The slab was designed with a cover of 25mm, a thickness of 15cm, and an effective depth of 12.495cm. • Provided reinforcement: As = 20mm² with T8 bars at 250mm center-to-center spacing. • The slab was evaluated for deflection and deemed satisfactory, with both maximum positive and negative moments being adequately resisted. • No shear reinforcement was required, as the shear stress (0.13 N/mm²) was well below the shear capacity (0.48 N/mm²). • Bar spacing was set at 251mm, less than the permissible spacing of 3d (373.5mm), to prevent cracking. 2. Beam Design: • The beam was designed with a total height of 50cm, aligned with ly/15 and ly/8 requirements. V • Flange width: 133.33cm; beam height: 40cm. • Design load: 221.52kN/m. • Reinforcement provided: 3T16 bars (603mm²). • Shear reinforcement was unnecessary as the shear stress (0.38 MPa) was below the shear capacity (0.443 MPa). • Deflection criteria were met with an actual span-to-depth ratio of 8.71, well below the permissible ratio (41.6). 3. Column Design: • The most loaded column (C-C2) was designed as a square column with dimensions of 400mm x 400mm. • Effective heights: 2350mm along the major axis, 2391mm along the minor axis. • The column was classified as a braced short column. • Reinforcement provided: 4T16 (804mm²) with 10mm diameter bars spaced at 300mm. • Stirrups: 8mm diameter bars. 4. Footing Design: • The footing was designed for a soil bearing capacity of 300 kN/m². • Serviceability load: 476.54 kN; ultimate load: 740.68 kN. • A square footing of 2.5m x 2.5m was selected, keeping the design stress within the soil’s bearing capacity. • Footing depth: 600mm to resist punching shear. • Reinforcement spacing: 335mm. 5. Stair Design: • The stair was designed for a height of 3000mm between the ground and first floors, with a flight length of 3m at an angle of 30.96°. VI • The design included 20 risers and 19 goings, each 300mm in dimension. • Landing reinforcement: 8T12 (901mm²); no shear reinforcement was required. • Span-to-depth ratios were within permissible limits, and 2T16 (226mm²) reinforcement was provided for the flight. • Moment for the flight: 13.28 kNm. This detailed overview covers both the architectural and structural aspects of the project, ensuring compliance with design standards while contributing to the growth of Gisozi’s urban landscape.