Boulder Historic Places Plan

The framing of the roof structure was not visible during the site observations; however, the roof framing appears in fair structural condition. Although the overall system is performing well structurally with no signs of deflection or failure, the sheathing surrounding the largest southernmost arch showed signs of moisture related deterioration (i.e. peeling and flaking paint, minor warping at the edges of the panels, etc.). This indicates it is likely that moisture has infiltrated the wood roof framing and that the wood framed structure below may have suffered some degree of moisture related deterioration. An investigation performed by JVA in 2014 noted that where the arches are in contact with the steel saddle base plates, they were showing signs of minimal moisture- borne deterioration. It does not appear any action was taken to remedy this, so the condition has likely worsened. Wall Framing Visible from the storage area at the north end of the Bandshell, the north wall of the structure is constructed of 2x4 wood studs with a supplemental inset wall constructed of 2x6 wood studs. Outside of the rear/north wall of the Bandshell, the arched roof system acts as both roof and walls (refer to the Roof Framing section above). The stud walls are in good condition. However, there is ivy growing on the wall at the rear of the Bandshell that can harbor moisture against the wood framing elements and encourage decay fungi to flourish. Floor Framing The stage floor is sheathed in plywood and covered with a non-slip coating. The floor was reconstructed in 1996 and consists of three bays of (2) 2x12 joists spaced at 16 inches on center that span in the east-west direction. Two north-south dropped steel W8 beam lines supported on the original isolated concrete pedestals divide the framing bays. Along the flared east and west sides of the building, the joists bear on a wood plate atop the foundation wall. No major issues such as excessive deflection or signs of deterioration were observed on the floor surface or on the framing from a cursory observation from the crawlspace. However, since the Bandshell is an open structure, it is prone to moisture damage. Because of this exposure and areas of failure of the flooring finishes, it is likely that areas of the structural subfloor are deteriorating. Lateral Force Resisting System (LFRS) The lateral force resisting system (LFRS) of the Bandshell consists of the roof sheathing and the wood framed roof/ walls. The LFRS is in good condition. It has performed well over the lifetime of the structure as evidenced by the lack of displacement or damage from lateral events, and previous analyses of the structure indicate that it has adequate lateral capacity for the lateral loads associated with the site. Amphitheater Seating Amphitheater seating faces the Bandshell stage. The amphitheater consists of a concrete slab that slopes toward the stage and rectangular reinforced concrete pedestals that support wood benches. Steel angle clips connect the wood benches to the concrete. Many concrete pedestals have started to spall. In some spall locations, the exposed rebar appears to only have had 1/4-inch cover. Some pedestals have areas of spider-web cracking and areas where the cement binder has weathered, exposing the larger aggregate. The painted wood bench boards show signs of wear including splitting, warping, and crushing at the connection locations.

Figure 1-26. Spalling at pedestal of Amphitheater Seating, 2020 (source: Ratio)

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