E-TN-CFD-BS-8110-97-004
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Design Load Combinations Page 1 of 1 ©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA AUGUST 2002 CONCRETE FRAME DESIGN BS 8110-97 Technical Note Design Load Combinations The design load combinations define the various factored combinations of the load cases for which the structure is to be checked. The design load combina- tions are obtained by multiplying the characteristic loads by appropriate par- tial factors of safety, γ f (BS 2.4.3.1.1, Table 2.1, 3.1.6). If a structure is sub- jected to dead load (DL) and live load (LL) only, the design will need only one loading combination, namely 1.4 DL + 1.6 LL. However, in addition to the dead load and live load, if the structure is subjected to wind (WL) and earth- quake (EL) loads, and considering that those loads are subject to reversals, the following load combinations for ultimate limit state might need to be con- sidered (BS 2.4.3): 1.4 DL 1.4 DL + 1.6 LL (BS 2.4.3.1.1, Table 2.1, 3.1.6) 1.0 DL ± 1.4 WL 1.4 DL ± 1.4 WL 1.2 DL + 1.2 LL ± 1.2 WL (BS 2.4.3.1.1, Table 2.1, 3.1.6) 1.0 DL ± 1.4 EL 1.4 DL ± 1.4 EL 1.2 DL + 1.2 LL ± 1.2 EL These are the default load combinations. In addition to the above load combi- nations, the code requires that all buildings should be capable of resisting a notional design ultimate horizontal load applied at each floor or roof level. The notional load should be equal to 0.015 times the dead load (BS 3.1.4.2). It is recommended that the user define additional load cases for considering the notional load in this program. Live load reduction factors, as allowed by some design codes, can be applied to the member forces of the live load case on a member-by-member basis to reduce the contribution of the live load to the factored loading. See Technical Note Overwrites Concrete Frame Design BS 8110-97 for more information.
Transcript of E-TN-CFD-BS-8110-97-004
Design Load Combinations Page 1 of 1
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA AUGUST 2002
CONCRETE FRAME DESIGN BS 8110-97
Technical NoteDesign Load Combinations
The design load combinations define the various factored combinations of theload cases for which the structure is to be checked. The design load combina-tions are obtained by multiplying the characteristic loads by appropriate par-tial factors of safety, γf (BS 2.4.3.1.1, Table 2.1, 3.1.6). If a structure is sub-jected to dead load (DL) and live load (LL) only, the design will need only oneloading combination, namely 1.4 DL + 1.6 LL. However, in addition to thedead load and live load, if the structure is subjected to wind (WL) and earth-quake (EL) loads, and considering that those loads are subject to reversals,the following load combinations for ultimate limit state might need to be con-sidered (BS 2.4.3):
1.4 DL1.4 DL + 1.6 LL (BS 2.4.3.1.1, Table 2.1, 3.1.6)
1.0 DL ± 1.4 WL1.4 DL ± 1.4 WL1.2 DL + 1.2 LL ± 1.2 WL (BS 2.4.3.1.1, Table 2.1, 3.1.6)
1.0 DL ± 1.4 EL1.4 DL ± 1.4 EL1.2 DL + 1.2 LL ± 1.2 EL
These are the default load combinations. In addition to the above load combi-nations, the code requires that all buildings should be capable of resisting anotional design ultimate horizontal load applied at each floor or roof level. Thenotional load should be equal to 0.015 times the dead load (BS 3.1.4.2). It isrecommended that the user define additional load cases for considering thenotional load in this program.
Live load reduction factors, as allowed by some design codes, can be appliedto the member forces of the live load case on a member-by-member basis toreduce the contribution of the live load to the factored loading. See TechnicalNote Overwrites Concrete Frame Design BS 8110-97 for more information.
