General Design Requirements
The general requirements for the structural design of buildings, structures, and components thereof are specified in this chapter. These requirements shall apply to all buildings and structures regulated by this code. All applied loads required for structural design shall be determined in accordance with the provisions of Chapter 2. Design parameters required for the structural design of foundation elements shall conform to the provisions of Chapter 3. Design of structural members using various construction materials shall comply with the relevant provisions of Chapters 4 through 12. The FPS equivalents of the empirical expressions used throughout Part 6 are listed in Appendix A.
The following definitions shall provide the meaning of certain terms used in this chapter.
Base Shear : Total design lateral force or shear at the base of a structure.
Basic Wind Speed : The fastest mile wind speed in km/h, at 10 metres above the mean ground level under terrain Exposure-B defined in Sec 2.4.4 and associated with an annual probability of occurrence of 0.02.
Bearing Wall System : A structural system without a complete vertical load carrying space frame.
Braced Frame : An essentially vertical truss system of the concentric or eccentric type which is provided to resist lateral forces.
Building Frame System : An essentially complete space frame which provides support for gravity loads.
CONCENTRIC BRACED FRAME (CBF) : A steel braced frame designed in conformance with Sec 10.5.17.8.
COLLECTOR : A member or element used to transfer lateral forces from a portion of a structure to the vertical elements of the lateral force resisting elements.
Buildings : Structures that enclose a space and are used for various occupancies.
Dead Load : The load due to the weight of all permanent structural and nonstructural components of a building or a structure, such as walls, floors, roofs and fixed service equipment.
Diaphragm : A horizontal or nearly horizontal system acting to transmit lateral forces to the vertical resisting elements. The term “diaphragm” includes horizontal bracing systems.
Dual System : A combination of Moment Resisting Frames and Shear Walls or Braced Frames to resist lateral loads designed in accordance with the criteria of Sec 1.3.2.
Eccentric Braced Frame (EBF) : A steel braced frame designed in conformance with Sec 10.5.17.9.
Fastest-mile Wind Speed : The highest sustained mean wind speed in km/h based on the time required for a one-mile (1.61 km) long sample of air to pass a fixed point.
Horizontal Bracing System : A horizontal truss system that serves the same function as a floor or roof diaphragm.
Intermediate Moment Resisting Frame (IMRF) : A concrete moment resisting frame designed in accordance with Sec 8.3.10.
Live Load : The load superimposed by the use and occupancy of a building.
Moment Resisting Frame : A frame in which members and joints are capable of resisting forces primarily by flexure.
Ordinary Moment Resisting Frame (OMRF) : A moment resisting frame not meeting special detailing requirements for ductile behaviour.
Primary framing system : That part of the structural system assigned to resist lateral forces.
Shearwall : A wall designed to resist lateral forces parallel to the plane of the wall (sometimes referred to as a vertical diaphragm or a structural wall).
Slender Buildings and structures : Buildings and structures having a height exceeding five times the least horizontal dimension, or having a fundamental natural frequency less than 1 Hz. For those cases where the horizontal dimensions vary with height, the least horizontal dimension at mid height shall be used.
Soft STOREY : Storey in which the lateral stiffness is less than 70 per cent of the stiffness of the storey above.
Space Frame : A three-dimensional structural system without bearing walls composed of members interconnected so as to function as a complete self contained unit with or without the aid of horizontal diaphragms or floor bracing systems.
Special Moment Resisting Frame (SMRF) : A moment resisting frame specially detailed to provide ductile behaviour complying with the requirements of Chapter 8 or 10 for concrete or steel frames respectively.
SPECIAL Structural System : A structural system not listed in Table 6.1.2 and specially designed to carry the lateral loads. See Sec 1.3.2 (e).
Storey : The space between any two floor levels including the roof of a building. Storey-x is the storey below level x.
Storey Shear, Vx : The summation of design lateral forces above the storey under consideration.
Strength : The usable capacity of an element or a member to resist the load as prescribed in these provisions.
Terrain : The ground surface roughness condition when considering the size and arrangement of obstructions to the wind.
Tower : A tall, slim vertical structure.
Vertical Load: carrying Frame : A space frame designed to carry all vertical gravity loads.
Weak Storey : Storey in which the lateral strength is less than 80 per cent of that of the storey above.