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Given: The ASCE 7-05 load combination permutations found in

Table 2.1.

Wanted: An electronic spreadsheet that ill appl! the load

combination e"uations to a #ariet! of load sources.

Solution: $! appl!in% the e"uations fre"uentl!& !ou ill soon learn

that there are times hen !ou 'no that a %i#en load combination

ill not control. (or e)ample& if !our load sources onl! include * and

+& then it is fairl! ob#ious that +,(* +C2 and AS* +C2 are the

controllin% e"uations and all others can be ne%lected. hen more

load t!pes %et included& the picture %ets a little less clear& but there

are combinations that can reduce the number of e"uations

considered.

The other option is to create a computation tool to handle it

all. Clic' hereto see a spreadsheet e)ample that does ust that. /n

this solution& e ha#e hi%hli%hted and put borders around the load

cases that are li'el! to control. Note that each row in the table

represents a single complete load case. The load sources are

in the columns. As !ou can see& includin% all the permutations ta'es

some eort The nice thin% about pro%rammin% the solution is that&

once done and pro#en& the tool ill sa#e !ou lots of time and %uess

or' in the future.

/t is possible to ma'e the spreadsheet much more compact b!

ritin% spreadsheet e"uations that include the load factors directl!

and that ma'e udicial use of ma) or min statements. The

e)ample here uses matri) multiplication to multipl! the coe3cient

matrices to the ri%ht side of the sheet a%ainst the matri) of load

source data to %et the resultin% load combination results. Thisma'es debu%%in% the sheet easier since !ou onl! need to chan%e

the coe3cient #alues to chan%e all the e"uations.

This spreadsheet can handle up to se#en load sources thou%h onl!

three are used here. The included load sources are the ones used in

e)ample problems 2.1 and 2.2.

http://www.bgstructuralengineering.com/BGASCE7/BGASCE7002/BGASCE7002_FullSpreadsheetExample.pdfhttp://www.bgstructuralengineering.com/BGASCE7/BGASCE7002/BGASCE7002_FullSpreadsheetExample.pdf

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/t should also be pointed out that the e)ample %i#en does not

completel! implement all the footnotes to the ASCE 7-05. /f !ou are

to create such a spreadsheet !ou ill need to loo' closel! at all the

ASCE 7-05 criteria.