I walked across the bridge twice and took a bunch of photos before I finally spotted evidence of a truss. And then it was a glimps through the trees. So I hiked down and around to get a view of the side and underside.
This is an odd bridge for automobiles. It feels more like a railroad bridge - so it makes sense it was built by the railroad.
Things I found odd about it:
- Narrow deck truss
- Timber bents and timber cribs substructure
- Timber floor beams
- Timber deck _without_ runners
- The approach spans are not in line with the main span. The south approach is pretty close, but the north approach is definitely not resulting in a curved appearance.
The deck has a very noticable dip in both approach spans. With it's listing as a truss, these dips made me very nervous! But the truss span is straight and level. It appears the bents under the approach spans have settled causing the dips.
The truss is pin connected, with 4 to 6 upset eye bars per panel. This seems heavy duty - but then the distance from the bottom chord to the top chord is only about 8 ft. (2.5 m) I think the short verticals means more tension on the bottom chord...
For future visitors, there is a road off of Mile Load Rd a bit south-east of the bridge that has a grade-level crossing of the railroad tracks. And keep an eye out, there's a lot of poison ivy.