User:Jshaikewitz/MacArthur Bridge

Introduction

St. Louis, Missouri has had its fair share of hits and misses when it comes to structural art. From the arguably misplaced magnitude of the Gateway Arch to the daring spans carrying the Eads Bridge over the Mississippi River, the city has struggled in creating consistently admirable work. The MacArthur Bridge poses an interesting case as what could once be argued as structural art in terms of efficiency, economy, and has become much less in a shifting context.

Structural Description

The MacArthur Bridge is made of steel trusses and four stone piers which support the 677 ft. span. The bridge was built with the intention of serving railroad traffic, and so the lower deck must be stiff enough to support the sudden weight of an oncoming train. In order to do so, the bridge uses three arch trusses to disseminate the live load and dead load the structure encounters and bring it down to the stone piers below, situated in the Mississippi River. The use of three trusses is rather efficient as it allows for a more simplified construction as opposed to a suspension bridge, but the need for multiple piers in the river was difficult to fund and required a significant amount of material. When the bridge opened to automobile traffic it was not as successful at accommodating the increased speeds and resulted in many crashes, earning the nickname “Death’s diving board.” Since the MacArthur Bridge required a lot of material to secure the bridge with piers, and it was not able to handle new types of live loads, the bridge, while now serving rail traffic again, does not entirely function as an efficient structure.

The bridge required bonds and grants, $3.5 million in 1906 and $2.75 million in 1914, in order to reach completion. Taxpayers found this necessary, though, as they saw the MacArthur Bridge as a means to break up the monopoly that had been created by the high toll prices that the Terminal Railroad Association charged with Eads Bridge. The bridge earned the name “The Municipal Free Bridge” since it was one of the few bridges that did not charge a toll fee. Unfortunately, the bridge later began charging a 10 cent toll which changed the bridge’s social reputation. While the bridge did provide an alternate option to the adjacent Eads Bridge, it was unable to truly hold its ground and maintain free tolls.

The elegance of the structure does not carry the true sense of the word. On one hand, its enormous height, that of a 14-story building, towers over the downtown area of St. Louis and its use of three trusses creates a sense of rhythm through repetition. However, despite the sense of lightness that seems to come from the use of steel, the bridge comes off as heavy and weighty. The overarching steel retains a jagged thickness while the height of the deck gives the trusses a compressed feeling. In addition, the stone tiers further take away a sense of lightness as they ground the bridge at four different instances. The bridge seems to lack any elegance, especially in comparison to the effective span of Eads Bridge.

Qualifications as Structural Art

Although at certain times in its history the MacArthur Bridge held aspects of efficiency, economy, and elegance, it is currently in the absence of those elements. It stands as a unique example of how a changing context can alter a work’s status as structural art.

References

BridgeHunter: MacArthur Bridge, http://bridgehunter.com/mo/st-louis-city/macarthur/

Built St. Louis: MacArthur Bridge http://www.builtstlouis.net/macarthur.html

External links

• Structural Art