Zogulitsa zitsulo zoponderezedwa zapita patsogolo kwambiri kuyambira 1950s m'zaka zapitazi, pali mfundo ziwiri zazikulu mu chitukuko chake. Choyamba, mphamvu ya zinthu pang'onopang'ono ukuwonjezeka, kotero kuti kuchepetsa kukula ndi kulemera kwa prestressed zigawo zikuluzikulu, ngakhale utachepa ntchito mtengo; Chachiwiri, pamaziko a kupititsa patsogolo mphamvu, tiyenera kulabadira chitukuko cha zipangizo ndi mkulu odana ndi dzimbiri ntchito, kuti patsogolo durability wa prestressed zitsulo zigawo zikuluzikulu ndi kusunga ndalama yokonza.