Skip to main content
Most King County offices will be closed on Monday, for Martin Luther King Day.  
King County logo
The Bridges of King County Through the Lens of T. P. Blum: 1931 - 1934

Deck, Pony and Through Trusses

There are three common placements of travel surfaces in relation to bridge structures: deck, pony and through. On the deck truss, traffic travels on top of the structure; on the pony truss, traffic travels between parallel structures that are not joined together with cross braces over the top; and with the through truss, traffic travels through the structure which is cross braced above and below the traffic.

Bridge_no_3174__June_8_1932__TPBlum

Steel Hill Bridge, Steel Hill Road, .75 miles E of Allentown: [Railroad Tracks], June 8, 1932. (Series 474, Bridge Number 3174. Section 11, Township 23N, Range 4E.)

TTY Relay 711

Monday, Tuesday, Thursday, and Friday: 9 am-4 pm

Please note the Archives is closed Wednesdays.