a reinforced concrete slab deck carried by transverse bents of concrete-encased structural steel. The piers are granite-faced reinforced-concrete. There were two gargoyles above the bridge on the south side that were removed when the bridge was upgraded several years ago. The four plaques on the central towers honor the original colonists, and veterans of the American Revolutionary War, American Civil War, and World War I. The 1922 Memorial Bridge includes the longest single concrete arch span in Massachusetts. Its self-supporting steel rib arches represent an uncommon refinement of Melan's original idea – by making the steel arches self-supporting, and using them to support their own load plus the weight of the formwork and the wet concrete during construction, an initial compressive stress was developed in the steel prior to the setting of the concrete. This prestressing of the steel allowed a much higher proportion of its ultimate strength to be utilized, allowing, in turn, the use of smaller and lighter arch ribs and a less massive substructure. 1996 rehabilitation project By the 1990s, the concrete above the arches was suffering from advanced Alkali-Silica Reactivity (ASR) attack. The 1996 rehabilitation project replaced the entire deck system. The decorative architectural elements were replaced either in kind using cast stone or replaced with architectural fiberglass reproductions. The viaduct over the railroad was replaced with adjacent precast/prestressed deck beams made continuous. This project was completed by Daniel O'Connell's Sons in 1996. See also List of bridges documented by the Historic American Engineering Record in Massachusetts List of crossings of the Connecticut River References External links Massachusetts Highway Department bridge data ''This article incorporates text from MassDOT, a public domain work of the Commonwealth of Massachusetts Bridges over the Connecticut River Buildings and structures in Springfield, Massachusetts Arch bridges in the United States Bridges completed in 1922 1922 establishments in Massachusetts Historic American Engineering Record in Massachusetts Monuments and memorials in Massachusetts Massachusetts populated places on the Connecticut River Springfield metropolitan area, Massachusetts Road bridges in Massachusetts Bridges in Hampden County, Massachusetts Former toll bridges in Massachusetts Concrete bridges in the United States Burr Truss bridges in the United States