Constants in Building Design & Analysis

By: Haseeb Jamal / On: Feb 01, 2017 / Design of

Constants in Building Design and Analysis

Component or System	ASD Load Combinations	LRFD Load Combinations
Foundation wall (gravity and soil lateral loads)	D + H D + H + L² + 0.3 (L_r+S) D + F[ + (L_r or S) + 0.3L"	1.2D + 1.6H 1.2D + 1.6H + 1.6L2 + 0.5(L_r + S) 1.2D + 1.6H + 1.6(L_r or S) + 0.5L²
Headers, girders, joists, interior load- bearing walls and columns, footings (gravity loads)	D + L“ + 0.3 (L_r or S) D + (L_r or S) + 0.3 L~	1.2D+ 1.6L² + 0.5 (L_r or S) 1.2D+ 1.6(L_r or S) + 0.5 L²
Exterior load-bearing walls and columns (gravity and transverse lateral load)	Same as immediately above plus D + W D + 0.7E + 0.5L² + 0.2S⁴	Same as immediately above plus 1.2D + 1.5W 1.2D + 1.0E + 0.5L2 + 0.2S⁴
Roof rafters, trusses, and beams; roof and wall sheathing (gravity and wind loads)	D + (L_r or S) 0.6D + Wu² D + W	1.2D + 1.6(L_r or S) 0.9D + 1.5WU⁵ 1.2D+ 1.5W
Floor diaphragms and shear walls (in-plane lateral and overturning loads)	0.6D + (W or 0.7E)	0.9D + (1.5W or 1.0E)

Presumptive Load-Bearing Value (psf)	Soil Description
1.500	Clay, sandy clay, silty clay, clayey silt, silt, and sandy silt
2.000	Sand, silty sand, clayey sand, silty gravel, and clayey gravel
3.000	Gravel and sandy gravel
4.000	Sedimentary rock
12.000	Crystalline bedrock