Best Practices for Historic Masonry Repair and Rehabilitation

About the report:

The most recently published update of the Virginia Department of Transportation’s (VDOT’s) historic bridge management plan, A Management Plan for Historic Bridges in Virginia: The 2017 Update, noted a number of special considerations regarding stone masonry on VDOT’s historic bridges (i.e., those state-owned bridges that are individually eligible for or listed on the National Register of Historic Places).  Key considerations included the types of masonry work identified on management plan bridges; various types of repair and stabilization methods; and references to compatible mortars for use on bridges of older construction.  The 2017 update of the historic bridge management plan also contained a fifth recommendation:  conduct an in-depth historic masonry study and produce a best practices document identifying procedures for repair and/or rehabilitation of historic masonry structures and masonry components, particularly those on VDOT’s historic bridges. This study addressed that fifth recommendation.

This study assembled data related to masonry in historic bridges, including archival documentary evidence, materials, and construction and repair technologies, and yielded a best practices document for facilitating appropriate management of VDOT’s historic bridges with stone masonry components.

The study concluded that (1) historic bridges in Virginia with stone masonry construction exhibit a number of different forms, materials, building practices, and technologies that reflect the time periods when the bridges were built (2) a variety of maintenance, repair, and rehabilitation practices have been used on these bridges; (3) best practices in historic preservation can evolve over time as additional information is acquired; and (4) knowledge of these various forms, materials, practices, and technologies, and the necessary specialized treatments required, must be taken into account when planning and undertaking maintenance, repair, and rehabilitation for the various types of stone masonry construction found in Virginia’s historic bridges.  Using the most appropriate practices as outlined in this report may help avoid inappropriate repairs and damage to stone masonry elements.

The study recommends that (1) the practices regarding bridge maintenance, repair, and historical documentation described in this report be used by VDOT structure and bridge engineers, environmental cultural resource personnel, and corresponding district staff; and (2) the information, including historical background, condition, and maintenance needs on specific bridges, included in this report be referenced in the forthcoming update of A Management Plan for Historic Bridges in Virginia (now in progress).  

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