H&H, the Engineer of Record for the rehabilitation of the historic Pennsylvania Avenue NW Bridge over Rock Creek and Rock Creek Parkway for DOT, was responsible for the initial site and bridge assessment, preliminary and final design, and construction support services.
The original 1858 bridge constructed of 48” cast iron water mains as the load-bearing arch members carried both water and vehicular traffic. In 1913, a concrete arch bridge was erected, encasing the aqueduct. The bridge underwent substantial rehabilitation in 1979. Major rehabilitation of the arch and superstructure was completed in Spring 2018 and is the project being presented herein. The scope of work included two phases of work.
A thorough hands-on inspection of the deck and sidewalk, framing system, bearings, columns, stone granite fascia, and concrete arch ribs of the bridge was performed, much of which was in a very confined space. It was determined that removing the center third of the deck (above the crown of the arch) would allow the contractor access to the arch bridge’s interior and facilitate the replacement of the floorbeam and stringer system and the deteriorated portions of the deck.
Recommendations made included deck and sidewalk repairs; removal and replacement of fire-damaged bearings, stringers, floorbeams, arch ribs, struts, and concrete columns; removal and replacement of the granite stone parapet; repointing and stone façade repairs; removal of existing utility and trolley “troughs” in the deck; installation of DC historical traffic railing along both curb lines; replacement of concrete soffit slabs between arch ribs to match the existing appearance; replacement of roadway joints and seals; replacement of roadway light poles with LED fixtures; upgrading, repairing sidewalks and curbs for ADA compliance; and improvements to the Rock Creek Parkway exit onto Pennsylvania Avenue. Meetings with DDOT and stakeholders, including coordination with DCWater, were also required to perform repairs and repaint the dual 48” diameter water mains.
Plans for bridge rehabilitation, including preliminary and final design of the structural rehabilitation plans, details, and special provisions, used a staged construction approach to rehabilitate half of the arch superstructure at a time while maintaining Eastbound traffic along Pennsylvania Avenue on the bridge. The Traffic Management Plan and Maintenance of Traffic (MOT) Plans facilitated the staged construction sequence for deck replacement while using a detour route to carry Pennsylvania Avenue westbound traffic. MOT plans for Rock Creek Parkway traffic permitted repairs to the arch ribs, substructure, and stone façade with little impact. Additionally, traffic signal retiming minimized impact to commuting times or the level of service. Metro bus routes and stops were temporarily modified during construction to accommodate the lane closures.
Pedestrian movements were maintained along the Rock Creek Trail that passes under the bridge as well as on the bridge along Pennsylvania Avenue for residents and businesses in Georgetown and the Foggy Bottom district.
Permitting – prepared, submitted, and acquired all permits needed to perform the inspection and repair work. In addition to the National Park Service, utilities on site included Verizon, DC Water, and PEPCO. Community Outreach and Public Relations, including attending meetings with DDOT, stakeholders, and pertinent Advisory Neighborhood Commissions (ANC).
Project Management, including all correspondence with DDOT, key stakeholders, subconsultants, internal H&H staff, and the contractor as appropriate; financial management and project invoicing; subcontracts and insurance requirements; and scheduling and coordination of staff to ensure the schedule was met. Advertisement and Award Support during the project’s bidding phase included attending the pre-bid meeting, answering contractor questions and preparing addendums, and preparing a bid cost analysis for the award based on the A+B bidding method.