The "Flood City" rebuilds historic bridge
The original Walnut Street Bridge spanning the Little Conemaugh River in downtown Johnstown, Pa. was built in 1917 after the Great Flood of 1889. The design of the bridge was an ornate two span cast in place concrete arch structure with matching exposed aggregate arches and parapets along with concrete balusters and balustrade caps. The bridge survived both the 1936 and 1977 Johnstown floods, even though the bridge is located in an area where the Little Conemaugh River flows with tremendous velocity. In both floods the bridge was submerged under several feet of swift water. As we neared the turn of the 21st century the bridge was so badly deteriorated the ornate concrete parapets and sidewalks had long since been removed for safety, and replaced with temporary aluminum railings. The entire bridge was in need of replacement.
 The bridge is located between the world renowned Johnstown Flood Museum and the historic Pennsylvania Railroad Train Station. The Pennsylvania Department of Transportation was challenged with the task of constructing a bridge using modern technology that replicated the 1917 architecture of the bridge. The bridge deck and super structure were completely demolished down to the lower portions of the abutments and pier. New bridge seats were cast in place on the existing abutments and pier to accept modern pre-stressed concrete box beams overlaid with a cast in place reinforced concrete deck. A. C. Miller Concrete was contracted to fabricate decorative precast concrete fascia panels that replicate the appearance of the original concrete arches of the bridge and conceal the pre-stressed concrete box beams. The panels were segmental and required matching of many complex and variable radii to replicate the contour of the original structure. A. C. Miller also supplied the fresh concrete for the cast in place exposed aggregate parapets and refuge bays to insure an exact match with the fascia panels. The bridge was also adorned with ornamental precast concrete light poles and brass ID plates cast into the parapets. The bridge opened on time despite a very aggressive reconstruction schedule mandated by the critical location of the bridge. Although the use of modern engineering technology insures a durable bridge, hopefully the new bridge will not be tested by future floods of the magnitude endured by its predecessor! |
A.C. Miller Products:
Standard Form:
Handholes
Manholes
Octagonal Forms:
Manholes
Culvert Box
Culvert Trench
Standard Utilities:
38y (Telephone)
75 kva (Transformer)
Caisson
Utility Building
Light Poles
Pre-Piped
Grease Trap
Accessories
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