| Key Facts |
| Bridge Name | Facility Carried / Feature Intersected | Location | Structure Type | Construction Date / Builder or Contractor |
| Belle Isle Bridge
MacArthur Bridge | East Grand Boulevard Over Detroit River | Detroit: Wayne County, Michigan | Concrete Deck Arch, Stationary | 1923 By: Unknown |
| Technical Facts |
| Rehabilitation Dates | Structure Length | Roadway Width | Main Spans | Approach Spans |
| 1984-1985, 1998 | 2356 Feet (718 Meters) | 61 Feet (18.6 Meters) | 19 | None |
This is an extremely long multi-span concrete arch bridge that
gives people access to Belle Isle, and the structure is the longest arch bridge
in the state of Michigan.
This bridge is extremely significant not only because of its length, but because it is a very early example of a cantilevered concrete arch. A cantilevered concrete arch does not function like a traditional arch. Traditional arch bridges require the arch to be a complete and connected arch to function. This arch bridge does not function in that way. Each half of each arch spans is a cantilever arm that is structurally independent from the other half of the arch in that span. Standing under a span of this bridge, a clear gap at the center of the span is visible. Indeed, on the outermost part of the arch, a decorative "keystone" was placed for aesthetic reasons to cover up this gap.
Wayne County Road Commission was among Michigan's counties, an innovative and creative road commission and they apparently made significant use of concrete cantilever arch structures. Other examples of concrete cantilever bridges in the county remain. These other examples are different from the Belle Isle Bridge, and feature a third central "suspended" span between the cantilever arms.
There is an interesting guardrail design on this bridge, but which does not appear to be original. The interesting guardrails are for the pedestrians, traffic is kept at bay via modern New Jersey barriers, which MDOT mentions were added in 1985. Obviously, this bridge goes over the side of the Detroit River that freighters do not use, which accounts for why a low-clearance bridge was built here.
A 1918 copy of a book entitled "Concrete engineers' handbook: data for the design and construction of plain and reinforced concrete structures" by George A. Hool et al. lists several bridges using this design, including an additional unidentified example in Wayne County, and the Hopple Street Viaduct in Cincinnati (now demolished). As such, the Belle Isle Bride may not be the second example of its kind, but is still an early example.
Above: Photo showing previous bridge at location. Source: Library of Congress
Information and Findings From MDOT
This monumental structure consists of nineteen spans, with a total
length of 2,356 feet. It features cantilevered arches, allegedly only
the second example of a bridge of this type in the United States when it
opened. The city of Detroit completed a major rehabilitation of this
bridge in 1984-1985, at a cost of $11.4 million. The project included
repairs to the arches, an entirely new deck and road surface, and the
installation of "New Jersey barriers" between the roadway and sidewalk.
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