Structural Condition The Arbor
The Arbor was built as an oval open structure with rubble masonry piers and a log roof system. Each wall supports five squared piers that taper in width. The stone base is capped with an oval pergola of peeled logs. The exterior features stone benches. Overall, the Arbor is in good structural condition. Foundation The foundation of the structure’s stone piers is likely composed of the same rubble masonry extending below grade. This base is also widened by stone benches integral with the bases of the piers. The foundation beneath the two interior wood posts is unknown as the concrete sidewalk is poured tight against the bases of the members, however, they likely bear on isolated stone or concrete foundation elements. No foundation elements were exposed or observed during the site observation. Overall, the foundation of the stone piers is in good condition. There is no evidence of settlement or settlement related cracking. The east timber post shows signs of decay at its base that bears directly on its foundation element and is tightly surrounded by the concrete sidewalk, both encourage moisture to remain rather than dry. (Re: Figure 1-19) The west post has new concrete around its base, indicating that it could have been recently replaced; however, this bearing condition could lead to the same moisture related decay pattern in the future. Floor The floor system of The Arbor is the concrete sidewalk on grade that passes through the opening in the structure. The sidewalk is widened at this location to include The Arbor’s curved ends. The concrete sidewalk is in good condition. Roof Framing The Arbor has an open roof structure composed of round, painted timbers with no sheathing or roofing. 11- inch diameter perimeter beams span between each of the stone piers. Additionally, there is a beam line along the long, center axis of the oval shaped structure; 11-inch diameter beams span between the two interior wood posts and the easternmost and westernmost stone piers. Four structural timber screws connect the beams to the posts while no mechanical connections were observed at the wood beam to stone pier bearing. Along the flat sides of the oval, between the two stone pier structures, 9-inch diameter timbers span across the structure and overhang each side. They are spaced at approximately two feet and are supported by the perimeter and central beams below. At the curved ends, 8-inch diameter radial beams span between the last joist and the perimeter beams, overhanging the perimeter. These rafters logs are likely connected to the beam support system below with structural timber screws similar to the beam to post connection; however, in this location, the connection is concealed and could not be confirmed during the assessment. The roof appears to be in good condition structurally; however, the timbers are directly exposed to the elements and the upward facing surfaces are showing signs of decay. It is our understanding that these were all recently replaced, indicating that decay of these members has happened over a short period of time and has been problematic. Walls The Arbor is an open structure and does not have true walls. The curved ends are each formed by five 18 to 24 inch rubble masonry stone piers that widen to join together at their bases. Two 11-inch diameter wood posts, approximately located at the foci of the oval structure, provide additional vertical support to the roof. The stone piers are structurally in good condition; however, there are areas of significant mortar erosion, especially around the bases of the piers, and patches of mortar repointing that are not compatible with the original structure. The stones near grade have a significant amount of lichen growth. This does not compromise the structure itself but changes its appearance and is an indication that moisture is prevalent. This indicates that more frequent maintenance of the mortar joints may be necessary. The timber posts have vertical cracks or checks; these are shrinkage cracks and are not of structural concern.
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Chautauqua Park
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