11 Loads Gravity Loads : dead loads, live loads, snow loads, … Load Path : A gravity load goes from its point of application on the structure to the foundation. As an example, the load applied on a slab will distribute to the beams, then to the girders, columns, and finally to the foundation. (Ref. Aghayere and Vigil, Structural Steel Design - A Practice Oriented Approach, Pearson, 2015) Lateral Loads : wind, earthquakes Load Path : A lateral load goes from its point of application on the structure to the foundation. As an example, the wind load applied on a vertical wall surface will transfer to the horizontal roof/floor diaphragms, then to the lateral resistance systems (moment frames, braced frames, shear walls, etc..), then to the structural frame elements, and finally to the foundation. (Ref. Aghayere and Vigil, Structural Steel Design - A Practice Oriented Approach, Pearson, 2015)
12 Building codes : International Building Code (IBC) Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers SEI/ASCE 7-10(ASCES), 2010. Gravity Loads : Dead Loads, Live Loads, Snow Loads, Rain Loads, .... Dead Loads : permanent loads (such as floor, walls, claddings, roof covering, fixed electrical and mechanical equipment, etc.) adhered to structures ASCES Chapter 3 and Tables C3-1 and C3-2 provide a summary of minimum design dead loads and densities for typical materials. Examples of structural materials : Plain concrete 145 lb/cu ft Reinforced concrete 150 lb/cu ft Structural steel 490 lb/cu ft Examples of common load estimates on building : Roof Dead Loads: Framing 5 to 8 psf Fireproofng 2 psf Metal deck 2 (1-1/2 " deck) to 6 psf (7-1/2 " deck) Mechanical/electrical 5 to 10 psf Floor Dead Loads: Framing 6 to 12 psf Fireproofing 2 psf Metal deck 1 ( 9/16 " deck) to 3 psf (3" deck) Flooring 4 to 7 psf Concrete 8 (lightweight) to 12 (normal) psf per inch of thickness Mechanical/electrical 5 to 10 psf Live Loads : loads that are not permanently located (often stipulated by the building code; for details, see ASCES Chapter 4) Basic Floor Live loads L 0 : (people, furniture, stored materials, movable equipment, etc..) See ASCES Tables 4-1 and C4-1 Examples : Residential Apartment Buildings 40 psf Office Buildings (offices) 50 psf uniform (2000 lb. concentrated) Garages (passenger vehicles) 40 psf (nonreducible) Class rooms 40 psf uniform (1000 lb. concentrated) Exit facilities (lobbies, etc.) 100 psf uniform (2000 lb concentrated) Stores (wholesale) 125 psf uniform (1000 lb concentrated)
13 Live Load Reduction : For any structural member (ASCES 4.8) that supports an area K LL A T more than 400 ft 2 ; and basic live load does not exceed 100 psf (except for members supporting two or more floors, live loads may be reduced by 20%) (except floors in places of public assembly) 𝐿 = ?
- Spring '14
- psf, Dead and live loads, Structural load