Transcript Case Study
Approaches to Historic Bridge Rehabilitation Case Study #1 Stenton Avenue Masonry Arch Rehabilitation Michael J. Cuddy, P.E. Principal Kara Russell Cultural Resource Specialist – Central Office Monica Harrower 1 Cultural Resource Specialist – District 6-0 Stenton Avenue Bridge (S.R. 3003) over Wissahickon Creek Case study #1 Whitemarsh Township, Montgomery County Bridge Description Built in 1914 Total length of 168 feet as measured from end to end of wingwalls 2-Span Masonry Arch Bridge (clear spans of 30’ and 26’) comprised of rubble-coursed field stone spandrel walls and parapets with concrete capstones that continue across the wingwalls. The voussoirs of the arch rings are partially parged. The intrados are parged, and concrete toe walls have been placed. 2 Case Study # Aerial View Showing Project Setting • Erdenheim Farm • Washington Valley Park 3 • Wissahickon Trail Case study #1 Stenton Avenue Masonry Arch Rehabilitation Completion Date: 2010 Cost: $1,050,000 Designer: TranSystems Owner: PennDOT Dist. 6-0 Contractor: J.D. Eckman Company 4 Case study #1 Significant Issues Associated With Project Overwhelming inventory of structurally deficient bridges. Increasing number of structural failures to its masonry arch population. Identified the need to develop a repair program that provided for expedited design process and cost effective repair methodology as well as one that preserved and renewed the cultural legacy of masonry arch bridges. 5 Case Study # Existing Structure Average daily traffic: 9,774 vehicles per day. Important transportation link. 6 Critical Condition due to masonry superstructure condition with several Priority “0” and “1” recommendations requiring timely repairs. Case Study # Structure Was in Critical Condition Sections of the masonry walls exhibited cracks, bulges and missing or displaced 7 stones. The structure was classified as Structurally Deficient. Overall, the barrels were in good condition and suitable for reuse in the rehabilitated structure. Substandard Bridge Railings Existing roadway width (20’-10”) was determined to be adequate for traffic volumes. Masonry barriers inadequate height and strength. 8 Substandard guiderail connections. How Significant Issues were Resolved Replace earth fill with lightweight concrete fill. Reconstruct stone masonry parapets with reinforced concrete cores and full 9 width moment slab. Repoint masonry as needed. Scour repair and protection. Temporary Support of Arches Arch “centering”, constructed of a timber and pipe scaffolding system, installed to 10 stabilize the arches during rehabilitation. The existing bituminous pavement, earth fill, masonry parapets and deteriorated sections of the spandrel walls were removed. Case Study # Replaced Earth Fill with Lightweight Concrete Fill Since the utilities would ultimately be encased in the concrete fill, carrier pipes were 11 installed that would permit the smaller diameter utility pipes to be installed after the bridge rehabilitation. Concrete fill was placed over pier and abutments to stabilize the structure during masonry reconstruction. Replaced Earth Fill With Lightweight Concrete Fill Deteriorated sections of the spandrel walls were reconstructed and concrete fill was placed up to sub-grade level of the new reinforced concrete moment slab. 12 Case Study # Finished Concrete Moment Slab Full width reinforced concrete moment slab with integral concrete barriers was 13 constructed on the concrete fill. The barriers were faced with stone and finished with an integral concrete capstone for aesthetics. Concrete Core Barrier Stone facing was also provided on the fascia. Repointing was performed in accordance with the PennDOT Stone Arch Bridge 14 Maintenance Manual and NPS Standards. Case Study # Finished Roadway Section A bituminous wearing surface was added to the concrete moment slab to provide the 15 appearance of the original structure. Note increased parapet height and improved guiderail attachments. Case Study # Finished Bridge 16 Case study #1 How was Section 106 handled PennDOT District 6-0 Stone Arch Bridge Management Plan 17 Ranked #57 (Not recommended for long term preservation). Pro-active approach by PennDOT engineering and cultural resource staff to develop rehabilitation procedures. Memo with project description prepared and forwarded to PHMC for review and approval. Finding of “No Adverse Effect”. All work performed within existing right-of-way. Case study #1 Lessons Learned/Conclusions Through the development of a streamlined repair methodology, PennDOT has been able to efficiently and cost effectively rehabilitate its stone arch bridges. Over the past year, construction contracts for 20 masonry arches have been let employing these procedures. Close coordination with the PHMC has resulted in findings of “No Adverse Effect”. Project has been awarded a 2010 Grand Jury Award by The Preservation Alliance for Greater Philadelphia 18