This is the fourth of six photos explaining how the Highway 169 Bridge across the Green River was built over a 16-month period between June 1932 and October 1933. This photo was taken from the Black Diamond side looking slightly down stream. The beginnings of the support tower seen in the Oct. 19, 1932 photo now fully rises 150 feet from the river level.
This tower is the T-shaped section to the right supporting truss spans extending in each direction. It was built in sequence, section by section in order to provide a balanced weight on each side. This tower segment will next be joined to the truss framework undergirded by concrete foundations projecting from the Enumclaw side. The T-shaped tower will also need to be connect further right to the Black Diamond bank.
Above the bridge a cable haulage system is faintly visible. Each of the heavy steel beams used to create the triangular trusses had to ferried high across the 700-foot distance separating the two river banks. Each beam likely weighed one to two tons. Workers joined the beams together with pins and rivets through in a system of stringers, braces, and struts. The design provides strength through the geometric principles of compression and tension being forced inward.
This photo by Thomas Blum was one of 38 taken to document construction of the bridge. Next week’s photo shows the finished span before decking was installed and the bridge framework connected to the upper banks on each side.
