Bowerman Barn Beam Evaluation & Repair

Added: Feb 10, 2014 2:47 pm SCOPE: The work of this Contract is to repair a timber frame connection of Bowerman Barn; to evaluate the rest of the connections to determine if other connections are solid or need repair; and to make recommendations on ways to mitigate other issues found during the evaluation.

BACKGROUND: Bowerman Barn is timber frame building built in 1878 that is listed on the National Register of Historic Places. While painting in 2011 it was noticed that one of the timber frame connections slipped and is in need of repair. The frame connections are believed to be kept together by concealed wooden dowels. In the early 1990s the structure was evaluated (see attached plans) and cable "X" bracing was added to help support the building when lateral loads were applied. One of the connections where an internal beam is supported by a perpendicular beam at the external wall is supported by column. One of the "X" bracing cables was attached to one of the beams. At this location, the upper beam has shifted with respect to the supporting members roughly one foot (see attached connection photos). It is unknown if the shift of the beams was due to over tightening of the cables that might have caused the dowel to have been sheared through or if due to the age of the connection, the connection has failed for some other reason and that this connection may be an indicator of what may be happening or about to happen in other timber frame connections. A Restoration Plan and Structural Analysis was conducted by an Engineering Consultant in 1993, and is available to assist the Contractor (see attached Description of structural members and connections).

WORK: The work is broken in to three main parts.

Repair Existing Connection: Contractor is to re-align the timber frame connection that is out of alignment described above and provide a positive connect that will keep the beams from shifting with respect of one to another. The materials/devices used must be in keeping with the historical nature of the building; submitted to and approved by Contracting Officer; and approved or be able to be approved by the State Historic Preservation Officer.

Evaluate Entire Building: Contractor is to evaluate the entire structure to determine what repairs and or modifications would need to be made to allow for the structure to be used as a working barn and areas open to the public. Evaluation shall include but not be limited to checking other existing timber connections to ensure positive connections, the stability of the foundation, rodent hole issues, realigning the braced walls on the South side of barn, bug damage to wood members and dry rot.

Recommendations: Provide a summary report on the evaluation portion of the contract identifying each area reviewed and the concerns/issues that were identified. If no issues or concerns were identified in an area, still state the area evaluated and method how evaluation was made. Areas with issues or concerns should include but not be limited: level of employee/public safety at risk; level of risk to the historical building; options for correcting the concerns/issues and mitigating the risks; providing a recommendation in resolving the concerns/issues considering employee's/public's safety, historical nature of building and costs of repairs; and providing an estimate of cost to make the recommended repairs.

LOCATION OF PROJECT
The Bowerman Barn (40˚ 54' 00.1" N, 122˚ 46' 0.42" W; Elevation 2450 feet) is located on Guy Covington Drive off of Highway 3 approximately 23 miles North of Weaverville, CA.

This solicitation will be available for electronic download on or around
February 25, 2014.