Bridge Construction Timber

AASHTO-referenced Coast Douglas Fir for highway, agricultural, and pedestrian bridge construction. Large dimension availability that most mills can't match.

Built for Load-Bearing Performance

Timber bridges demand the highest structural performance — high bending strength, high shear resistance, dimensional consistency, and species documentation for engineering review.

Coast Douglas Fir is one of the few species specifically referenced in AASHTO LRFD Bridge Design Specifications. Its strength-to-weight ratio, availability in large cross-sections, and documented design values make it the default choice for timber bridge contractors across North America.

We supply bridge contractors with stringers, decking, bents, and pile caps in the large dimensions that your distributor can't source — 8x8 to 36x36 and lengths to 50ft.

Key Specs for Bridge Applications

Species Coast Douglas Fir (Pseudotsuga menziesii)
Design Standard AASHTO LRFD + NDS
Grade Select Structural or No. 1 (grade stamps available)
Max Section 36x36 on request
Max Length Up to 50ft
Grade Stamp WCLIB — available on request

Common Bridge Timber Sizes

Size Application
12x12 Primary stringers, bents
12x16 Heavy stringers
14x14 Main bents, caps
16x16 Heavy bents, pile caps
18x18 Major span stringers
20x20 Large-span primary members
24x24 Extreme-load applications
30x30 Heavy-load primary members
36x36 Extreme-load — on request

SAM.gov Registration

Washington Timber Company is pursuing SAM.gov registration for federal contract eligibility. Contact us regarding state DOT approved vendor status for your project requirements.

Bridge Project Inquiry

Tell us your span, load requirements, and section sizes. We'll respond with availability and pricing within one business day.