They hope to reduce both the number of components needed in a construction job and their weight—by replacing solid supports with hollow tubes, for example.
他们希望减少建筑工作所需的部件数量和重量，例如，用空心管代替实心支架。
2
Civil engineers build mathematical models of Bridges and other structures to calculate how much weight and stress they can bear before committing to an expensive construction phase.