Fomu ya girder yokonzedwa kale ili ndi ubwino wake chifukwa ndi yolondola kwambiri, yosavuta, yobwerera m'mbuyo, yosavuta kuchotsa komanso yosavuta kugwiritsa ntchito. Ikhoza kukwezedwa kapena kukokedwa pamalo oponyeramo zinthu mozama, ndikuchotsedwa pang'onopang'ono kapena pang'ono pambuyo poti konkire yapeza mphamvu, kenako nkutulutsa nkhungu yamkati kuchokera pa girder. Ndi yosavuta kukhazikitsa ndi kukonza zolakwika, ntchito yochepa, komanso yogwira ntchito bwino.
Njira yolumikizira mlatho imagawidwa m'magawo ang'onoang'ono, omwe amakonzedwa kale m'bwalo lowongolera bwino, kenako, amaperekedwa kuti ayikidwe ndi zida zabwino zomangira.