McMullan Receives Certificate of Appreciation from National Park Service for Burnside Bridge Restoration

Burnside Bridge_CertificateofAppreciation

In May 2017, McMullan & Associations, Inc. received a formal “Certificate of Appreciation” from the National Park Service (NPS) in recognition of our “exceptional support for the restoration of the historic Burnside Bridge, preserving this national treasure for present day and future generations.” The certificate was signed by NPS Superintendent Susan Trail.

McMullan worked with the National Park Service to faithfully restore the most well-known Civil War bridges to its original condition, which had suffered from stone fallout and water damage. The beautifully proportioned 192-foot bridge runs over the Antietam Creek in Sharpsburg, MD, and is part of the Antietam National Battlefield Park. In September 1862, this park was the battleground where nearly five thousand Americans lost their lives.

Project Background

In collaboration with Peck, Peck & Associates as part of an IDIQ contract with NPS, McMullan provided Title I, II & III architectural and engineering (A/E) services for the structural rehabilitation of the historic Burnside Bridge. The work occurred in four stages for investigation and pre-design, schematic design and design development, construction document preparation, and construction management services.

The  bridge, originally constructed in 1836, is a stone and concrete three-arch structure with mass walls bearing on a mortared stone foundation. Sidewalls are approximately 18-inches to 24-inches thick from top to bottom. Its stone walls consist mainly of parge and aggregate infill. There was no below-grade access to the stone foundations, rendering no visibility of the foundations without excavation. The wearing course of the 12’ wide x 193’ long bridge was replaced in 1955 and consisted of gravel and asphalt. Subcourse concrete with steel reinforcement was added during this structural rehabilitation which replaced original soils.

Prior to commencing the task order work for NPS, it was noted that there was apparent water damage, cracking and bulging in the exterior stone walls on each side of the bridge. Several masonry and mortar repairs had taken place over the life of this pedestrian bridge. Cracks and mortar separation were clearly visible, particularly in the upper stone sections. A wooden cap was installed in 1964 replacing a concrete cap installed in 1913 to protect the top of the parapets and to restore the natural appearance of the caps. In addition to numerous re-pointing of bridge stonework from the 1940s to 2004, significant structural stabilization work was performed in 1988-1989 where piers and undersides of arches were cleaned, and re-pointing and road course leveling took place. Recent repairs had been completed by NPS preservation masons with work documented as it progressed.