▁to ▁form ▁longer ▁lengths ▁and ▁is ▁used ▁in ▁door j amb s , ▁m ould ings ▁and ▁stud s . ▁It ▁is ▁also ▁produced ▁in ▁long ▁lengths ▁and ▁wide ▁dimensions ▁for ▁flo ors . ▁ ▁Be ams ▁I - jo ists ▁and ▁wood ▁I - be ams ▁are ▁"" - sh aped ▁struct ural ▁members ▁designed ▁for ▁use ▁in ▁floor ▁and ▁roof ▁construction . ▁An ▁I - jo ist ▁consists ▁of ▁top ▁and ▁bottom ▁fl anges ▁of ▁various ▁width s ▁un ited ▁with ▁web s ▁of ▁various ▁depth s . ▁The ▁fl anges ▁resist ▁common ▁b ending ▁str esses , ▁and ▁the ▁web ▁provides ▁she ar ▁performance . ▁I - jo ists ▁are ▁designed ▁to ▁carry ▁heavy ▁loads ▁over ▁long ▁distances ▁while ▁using ▁less ▁l umber ▁than ▁a ▁dimensional ▁solid ▁wood ▁jo ist ▁of ▁a ▁size ▁necessary ▁to ▁do ▁the ▁same ▁task ▁[ 1 ]. ▁As ▁of ▁ 2 0 0 5 , ▁approximately ▁half ▁of ▁all ▁wood ▁light ▁fr amed ▁flo ors ▁were ▁fr amed ▁using ▁I - jo ists ▁[ 2 ]. ▁ ▁Tr uss es ▁Ro of ▁tr uss es ▁and ▁floor ▁tr uss es ▁are ▁struct ural ▁frames ▁re lying ▁on ▁a ▁tri angular ▁arrangement ▁of ▁web s ▁and ▁ch ords ▁to ▁transfer ▁loads ▁to ▁reaction ▁points . ▁For ▁a ▁given ▁load , ▁long ▁wood ▁tr uss es ▁built ▁from ▁smaller ▁pieces ▁of ▁l umber ▁require ▁less ▁raw ▁material ▁and ▁make ▁it ▁easier ▁for ▁AC ▁contract ors , ▁pl um bers , ▁and ▁elect r icians ▁to ▁do ▁their