The I-35 bridges are two identical 486-foot long steel girder bridges. The girders are constructed from a series of very large steel I-beams. They sit on piers that are large pilings topped off with concrete pier caps. The deck and guardrails are reinforced concrete. These bridges were built at a time when the Interstate highway system was rapidly expanding. The key design features were economics and time to build. It had to be quick and cheap. As a result, the bridges a devoid of any decorative features. They do, however, serve their purpose very well. One hardly even realizes that they are crossing the dangerous Saint Louis River as they motor past at 70 miles per hour.
The river elevation at the I-35 bridges is 1,100 feet. For this point, it is a 500 foot vertical drop to Lake Superior. The river will drop this distance in just 6 miles (as the crow flies).
The photo above is looking south towards the upstream north side of the I-35 Bridges. The vantage point is along the west bank of the river being a car dealership near the intersection of MN-45 and Highway 61.