PBS2 个月
Beam bridge
A beam or "girder" bridge is the simplest and most inexpensive kind of bridge. According to Craig Finley of Finley/McNary Engineering, "they're basically the vanillas of the bridge world." ...
PBS4 年
Beam Bridge
A beam or "girder" bridge is the simplest and most inexpensive kind of bridge. According to Craig Finley of Finley/McNary Engineering, "they're basically the vanillas of the bridge world." ...