General Objectives of Structural Design
- Structure designed should satisfy the criterion of ultimate strength.
- Structures should satisfy the serviceability.
- It should satisfy the stability against overturning, sliding and bucking.
- Obtaining an architectural design of a regular residential multi-storey building.
- The design of column, wind resisting system, and type of foundations will be determined taking into consideration the architectural drawings.
- Identification of structural arrangement of the plan.
- Modelling of the building for the structural analysis.
- Sectional design of structural components.
- Structural detailing of members and the system.
- Establishing the structural system for the ground, and repeated floors of the building.
Types of Buildings
- Apartment Building: Apartment buildings are multi-story buildings where three or more residences are contained within one structure.
- Office Building: The primary purpose of an office building is to provide a workplace and working environment for administrative workers.
Loads on the Structure
- Dead Loads
- Imposed Loads
- Wind Loads
1. Dead Loads
- RCC Slab
- Beams & Columns
2. Imposed Loads
- Imposed also known live loads
- Loads over the floor i.e. Load of persons it is calculated as 1 KN/m2.
- This load is applied over the length of structure.
3. Wind Load
- Wind is air in motion.
- Wind loads are calculated according to IS:875.
- Intensity of wind and exposure are applied in the direction as required.
- The concrete mix should be workable.
- Concrete is a durable material which is ideal for many jobs.
- It is important that the desired qualities of the hardened concrete are met.
- Economy is also an important factor.
- Slabs design
- Columns design
- Shear walls design
- Foundations design
General Principles of Design
1. Site Selection
- Depending on ambient noise level.
- Background noise should not be more than 40-45 db.
2. Size and shape
- In relation to the number of audience required to be seated.
- Average height- 6 to 7.5m, fan shape is considered best, sidewalls shall not be more than 100 degrees, Farthest seat shall not be more than 23m with the curtain line.
3. Roof and Celling
- False ceiling, sound proof material.
- Rear portion of ceiling is treated with sound absorbing material.
- Successive seats have to be raised over preceding ones, so that the listener head is about 12cm above the path of sound, which would pass over the head of the front person.
- Angle of elevation of the inclined floor in auditorium should not exceed 8 degrees.
- 20% of the seating area should be allocated for lobby.
- The angle subtended with the horizontal at the front most observer should not exceed 30 degrees.
- Distance between the stage and front row should be 3.6m-4.5m.
- Width of seat- 45 to 56cm.
- Distance between seats back to back- 85 to 106cm.
6. Reverberation Time
- Reverberation time is defined as the time it takes for an impulse of sound in a room to decay 60DB, or one millionth of the original level. This value is affected by most everything in the room, including rom volume, absorption of room materials, diffusion from surfaces, and room temperature and pressure.
7. Distribution of Acoustics Material
- The rear wall
- The balcony parapet
- Any areas which may reflect sound back to the stage
- Concave areas
8. Sound Absorbing Material
- In an average hall, most of the absorption is provided by the audience. It is therefore, become desirable to introduce special absorbent on ceilings and walls will provide the requisite amount of absorption so as to achieve optimum reverberation-time.
- This project concerns the feasibility of construction of an auditorium with good acoustic properties.
- The design of slab, beam, column, rectangular footing and staircase are done in limit state method which is safe at control of deflection and in all aspects.
- Using Staad.PRO software, the design consideration has been taken as per the is codes. The design is safe in all conditions.
- On comparison with drawing, manual design and the geometrical model using Staad.PRO the area of AST required for the beam, column, footing and slab are comparatively similar to that of the requirement.
- It involves the application of earlier course work to carry out the analysis and design of components of structure.
- The construction of auditorium presents a solution for many cultural programmes being held.
- It was analysed using STAAD.Pro using generic loading and AutoCAD for drawing and detailing the c/s and l/s of structural members.