The Thru Truss Series is our naming convention for a high or box truss bridges. It involves the addition of sway braces and portal frames (transverse bracing) to low truss bridges which increases their span capability. This extends their applicability to clear-span longer gaps. In doing so, the vertical clearance above the bridge’s roadway sets the truss height.

Because of the deeper truss girders, shipping of full-depth pre-assembled sections is much more difficult and many times not available.  The pre-assembly is usually limited to attaching gusset plates to the chord members with vertical and diagonal members being added in the field.  This requires more planning by the contractor to assemble the truss girders and move them into position.


Width Range: 12 ft. – 18 ft. / Span Range Max: 300 ft. – 220 ft.
Width Range: 20 ft. – 34 ft. / Span Range Max: 275 ft. – 200 ft.
Width Range: 35 ft. – 44 ft. / Span Range Max: 225 ft. – 175 ft.