A lattice girder is a truss girder where the load is carried by a web of latticed metal.[1]
The lattice girder was used prior to the development of larger rolled steel plates. It has been supplanted in modern construction with welded or bolted plate girders, which use more material but have lower fabrication and maintenance costs.
The term is also sometimes used to refer to a laced strut[2] or laced tie, structural members commonly made using a combination of structural sections connected with diagonal lacing. This form allows a strut to resist axial compression and a (tie) to resist axial tension. A lattice girder, like any girder, primarily resists bending.
The component sections may typically include metal beams, channel and angle sections, with the lacing elements either metal plate strips, or angle sections. The lacing elements are typically attached using either hot rivets or threaded locator bolts. As with lattice girders, laced struts and ties have generally been supplanted by hollow box sections, which are more economic to produce with modern technology. In some case seismic retrofit modifications replace riveted lacing with plates bolted in place.