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Replacement of CTDEP Bridge No. 6307 over Chatfield Hollow Brook
Chatfield Hollow State Park
Killingworth, Connecticut

THE CHALLENGE: Reputedly constructed in the early 1960s, the Connecticut Department of Environmental Protection’s triple barrel reinforced concrete pipe Bridge No. 6307 carried 500 vpd over Chatfield Hollow Brook, providing the sole public exit roadway from Chatfield Hollow State Park. Extensive deterioration of the existing stone headwalls resulted in a rating of “structurally deficient” by the CTDOT. A replacement superstructure was required that: improved inadequate hydraulic capacity, enhanced site aesthetics, and could be constructed while the park was closed for the season. THE SOLUTION: The new bridge consisted of an AASHTO HS20 designed, twin 13ft. span by 6ft. rise precast reinforced concrete box culvert. The 22ft. long culvert carries a horizontally curved roadway over Chatfield Hollow Brook and includes cast-in-place reinforced concrete cut-off walls, return walls, wingwalls and parapets. A membrane waterproofing with bituminous protective course was placed over the box culvert prior to placing the roadway gravel.		To enhance site aesthetics, all exposed faces of the parapets and wingwall stems were form-lined and color-stained. For added realism, the parapet end blocks were cast to compliment the form liner pattern to simulate the placement of individual stones. The parapet’s two-rail aluminum pedestrian rail system was anodized, and a steel-backed timber approach rail pressure treated with an oil-borne preservative was used at all four approaches. CTDEP Bridge No. 6307 was closed for the construction of the new bridge, which was completed in 2002 after approximately 5 months of construction time. Final construction cost was approximately $250,000. Complete bridge engineering services were provided by Nathan L. Jacobson & Associates, Inc., of Chester, Connecticut. Project management was directed by a principal of the firm specializing in bridge design. Services included survey, design, shop drawing review, and periodic bidding and construction administration and inspection.

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