The Olive Street Bridge (Niles-McDonald Viaduct) in Trumbull County, OH, was originally constructed in 1920 and underwent major rehabilitation in 1976. Since the 1976 rehabilitation, the 20-span bridge had undergone serious deterioration—most prominently to the prestressed concrete box beam spans. The damage was so extensive that the load limit was ﬁrst reduced to three tons in 2008, then closed to all traﬃc in 2009 after trucks continued to use the structure. This restriction placed a hardship on ﬁrst responders, school buses, local deliveries and sanitation services.
With approximately 3,500 vehicles using the bridge per day, the closure also placed a hardship on local businesses, residents and motorists who relied on easy circulation and accessibility in the village of McDonald and the city of Niles. The replacement of the structure was critically important to the communities’ collective long-term survival.
The project was initiated with a rehabilitation or replacement study. A structural analysis was performed to determine if the piers of the box beams spans and concrete arches could be salvaged in some way for reuse. The study ultimately concluded that a full replacement with a shorter, four-span structure was the most cost-eﬃcient means to move forward. An additional beneﬁt with the replacement option came the opportunity to improve the horizontal and vertical alignments in combination with using an embankment ﬁll to improve the design speed for the facility.
Focusing on Partnerships and Coordination
Because of its location and many agencies involved, the project required coordination from day one to make it a success. Close collaboration between the Ohio Department of Transportation, Trumbull County Engineer’s Oﬃce, utility companies, stakeholders, ms consultants and A.P. O’Horo Company promoted the successful design and construction completion. This partnership was particularly evident by maintaining the original completion date, though the original start of construction was pushed back more than ﬁve months due to delays in the relocation of the sanitary force main.
Coordination with two railroads was also required—an active Norfolk Southern track along the Mahoning River and an abandoned CSX (former B&O Railroad) line at the existing north end span. The adjacent Niles Wastewater Treatment plant was also a consideration. Planning was made to ensure that 24-hour operations were uninterrupted.
In addition to coordinating a number of entities, the project also created physical challenges, including:
- A 12-inch sanitary force main carried on the existing structure that could not be out of service
- A 12-inch-high pressure gas line carried on the existing bridge
- AT&T and electric service lines carried on the existing bridge
- A number of buried gas and telecommunication lines throughout the site, requiring subsurface utility engineering services for avoidance and/or relocation
- Environmental plan notes that detailed requirements for work within the Mahoning River and 100-year ﬂoodplain due to hazardous/solid waste classiﬁcation
- Demolition of entire viaduct structure, including the span over the Norfolk Southern Railroad and arch spans over the Mahoning River; the river portion requiring an elaborate temporary access ﬁll plan with cost estimating
- Construction of a 411-foot-long mechanically stabilized earth (MSE) retaining wall while maintaining continuous access to the bordering plant operations
A New, Safer Bridge
The bridge replacement was designed with added safety as an additional focus. Engineers designed a 35-mph gentler horizontal curve, combined with a lower vertical grade line that enabled construction of direct access drives to service the Niles Wastewater Treatment Plant to the east and to promote industrial development for properties to the west. The improved safety through the design of the ﬂatter horizontal curve also increased the stopping sight distance over existing conditions.
The aged viaduct-style bridge consisted of 18 prestressed concrete box beams spans and two open-spandrel concrete arches spanning the Mahoning River. The shorter, 427-foot replacement bridge is just four spans, and the MSE retaining wall with concrete coping provides an additional enhancement. The overall result is a considerable improvement compared to the original dilapidated structure.
Celebrated by the Community
Reopening Olive Street via the bridge replacement project was a beneﬁt to Niles, McDonald, and Trumbull County.
Because a mutual aid agreement exists between Niles and McDonald, ﬁre protection services are restored to prior levels. Evidence of the enthusiasm for the bridge restoration was in full eﬀect when the ribbon-cutting ceremony was held. A parade, complete with ﬁreworks, press coverage and speeches from local public and state oﬃcials, was a testimony to the importance of the Olive Street Bridge reopening.
Given the high-proﬁle nature of the bridge project to the local communities, the design and construction teams kept the public’s interests at the forefront so the bridge could be reopened as early as possible.