The Allen Street Bridge in Kelso was designed to complement its surroundings and look like bridges in Kelso’s Scottish sister city.

The Allen Street Bridge is a seven-span concrete structure crossing the Cowlitz River and an adjacent railroad track in Kelso. It replaced a corroding steel bridge and is expected to require little maintenance over its lifetime.

Cast-in-place concrete was used for the bridge’s drilled shaft deep foundation, abutments, interior piers, pier diaphragms, roadway deck, approach slabs, sidewalk, traffic/pedestrian barriers, approach wall fascia panels and approach wall planters.

The city of Kelso wanted a bridge that, in addition to being functional, fit into its surroundings and conveyed an impression of Kelso’s sister city in Scotland. That was accomplished by several means.

First, the traffic/pedestrian barrier was changed to an open baluster type rail, with aesthetic pilasters that support the luminaries — similar to those used on the old bridge and on the state Route 4 bridge over the river to the north.

One of the most prominent aesthetic features on the new bridge is its pier design, which uses Gothic arches to span between the pier columns and reflect the architecture of Scotland. Form liners were used on the arches to create a look of split-face stone supported by a smooth-cut stone arch soffit.

The east approach to the bridge covers two city blocks, using a mechanically stabilized earth wall for support. To improve the aesthetics of the approach, ready-mix concrete was used to create tilt-up concrete fascia panels for the wall face.

Ready-mix concrete also was used to create planters along the approach walls. Form liners on the tilt-up panels and planters created the look of brick and sandstone.