Twonineteenth-centuryinventionsledtoarevolutioninbridgebuilding.ThesewerePartlandcementandmass-producedsteel.Cementisthevitalingredientofconcrete,andmassconcretecanbeusedtobuildpiers,abutments(banksupports),andarchesof“artificial”stonetoanyrequiredshape.W (共 5574 字) [閱讀本文] >>