Monday, May 30, 2005

Pinned Truss Bridge Detail

Posted by Hello

This photo shows the eyes on the truss members of a pinned lower chord metal truss bridge in Morrow County. It was built in 1874. These members are in tension so they can be thin as there is no concern about buckling. This structure allows flexibility of the bridge and better distribution of loads. Newer bridges tended to have heavier members with riveted or welded joints.

Wednesday, May 25, 2005

Morrow County, Ohio, Tubular Bowstring Bridge.

The Whetstone Bridge Posted by Hello

Well I'm continuing to explore Morrow County, Ohio and I have not been disappointed. On Saturday I found 11 of the 13 bridges that were listed as extant actually were! That's a very good percentage in this "game".

The pictured bridge was constructed in 1879 and is still in daily service in Mt. Gilead, Ohio. Called a Bowstring you can see how it gets its name. The arch (Bow) supports the bridge loads. The lower cord acts like a bowstring and is in tension. This is one of the few Bowstring bridges in Ohio still in service.

This bridge is similar to the abandoned Mill Road Bridge in Knox county that I pictured earlier (look back).

Sunday, May 15, 2005

Morrow County Road Trip #2

Pratt Half-Hip in Morrow Co. Posted by Hello

Morrow County seems to be a haven for metal truss bridges such as this nice little Pratt Pony. Six of the seven targeted bridges on today's ride were still extant. Even the seventh looked like a very recent replacement so I hadn't missed it by much!

Spring is well upon us now, which makes for better riding but bare trees reveal the bridges better. Also old bridges and dead looking trees blend better asthetically don't you think?.

Saturday, May 07, 2005

A Knox County Pratt Truss Bridge

Isolated Bridge in Knox County Posted by Hello

Finally after 2 weeks of lousy weather the sun returned and I got the motorcycle out for another road trip. I returned to Knox County to check out another 6 bridges in the east part of the county that were listed by ODOT as still existing. This picture shows the only original bridge actually remaining. After crossing over this bridge the gravel road became really bad. I had to ford through some water then I could see a sharp turn on an uphill section with exposed ledges of rock and lots of loose stuff. This did not seem like a good road for my street bike so I doubled back (through the water again). The good old GPS plotted me an alternate route to the next bridge (which turned out to be completely gone).