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HomeMy WebLinkAboutDCI Bozeman Deaconess Hospital East Wall Site Visit 02.11.2022 February 11, 2022 Ben Abbey Chief Building Official City of Bozeman 20 East Olive St, PO Box 1230 Bozeman, MT 59715 Re: Field Visit –Bozeman Deaconess Hospital – East Wall 15 West Lamme Street, Bozeman, MT Ben: Andy Holloran contacted me and asked that I visit the above site to investigate the east wall of the original Bozeman Deaconess Hospital (BDH) following the demolition of the Mountain View Care Center. Matthew Hubbard (DCI), Andy Holloran (Home Base Partners), and Bryon (Omdahl Excavation) were present on site at approximately 8:30am on February 11, 2022. Our visit was requested due to concerns about the stability and integrity of the newly exposed portion of the east wall of the original BDH building. As noted in our Structural Conditions Assessment in 2020 as well as our Supplement to that report in August of 2021: “The Mountain View Care Center (MVCC) was an addition to the original hospital building and originally served as the extended care facility. When constructed, it appears the new addition was built directly adjacent to the existing building with its own structure, creating a double wall at the interface. Openings in the original building exterior wall were created to tie the spaces together and presumably mechanical, electrical, and plumbing services pass between the buildings. While we have not been able to observe this condition, we assume these buildings also bear on separate foundation systems given the timing of their construction.” Observations · With the MVCC addition demolished, we observed that the addition was built adjacent to BDH and there was a double wall condition with very little interconnectivity. The foundation system, however, does not appear to be completely separate. Concrete foundation walls appear to be integral to a large footing or slab system as noted at grade. · Wall construction – We observed the newly exposed east wall consists of an exterior brick wythe and interior hollow clay tile wythe. There does not appear to be any reinforcing, grout, or other structural connectivity between the wythes or to the primary concrete building frame. · Different Brickwork – We immediately noticed that the newly exposed east wall is of a completely different brick material than the rest of the hospital building. Our best explanation is that when the hospital was originally built, an expansion was anticipated. In construction of this period, cheaper brick material was often used where it would be covered up or modified at a later date. Oddly, the south end has a straight vertical seam between the two brick types with no brick interlock, inter-coursing, or tie courses for stability and integrity. The north interface is tied in at a corner with typical brick coursing interlock. · Openings – None of the major openings at the main level or second level appear to have any structure to them. Openings of this size would require steel angles or other header elements coupled with some type of jamb structure. As noted in the photos, the edges of the brick and hollow clay tile are jagged and exposed and no header elements are present to support the brick above. · Southeast Corner BDH – It was noted that some settlement appears to have occurred at the southeast corner of the hospital building. The interface condition is also complex at this location with multiple corners and materials. A portion of the MVCC walls and floor slab concrete was left in place. Byron shared that careful attempts at demolishing this material resulted in stress and displacements in the brick wall behind it. · Water Damage – The low roof interface to the existing concrete wall appears to have allowed water infiltration between the double wall assembly. Rust staining of the brick, metal attachments, and what appears to be deterioration of the brick and mortar itself are present. Conclusion It is our understanding that the original Bozeman Deaconess Hospital building was determined to be “an unsafe structure and poses a dangerous condition to the public” in your report dated October 6, 2021. With the Mountain View Care Center addition demolished, we were able to observe the actual building conditions at the interface. Based on our observations above, this wall furthers the overall unsafe condition of the building and poses a significant threat to the local area around the wall. The two large unreinforced openings at the ground level create a large, weakened zone and inadequate support of the weight of the brick above. Additionally, this wall is very minimally tied into the rest of the building over its three-story height. With no inter-coursing of the bricks on the south end over the full height of the wall, significant unreinforced opens, brick deterioration, and limited, to no structural attachment into the concrete frame structure, any excess forces on this wall from a wind or seismic event could result in the wall collapsing. Shoring this wall would be significant both in terms of effort and cost. Given the “unsafe structure” designation and planned demolition of the building in the near term, it is our recommendation that demolition continue into the hospital building. In the interim, the area surrounding the hospital building should be fully secured and the public should not be within one building height horizontally of the newly exposed portion of the east wall. Considering the partially demolished condition and the potential for damage to have occurred during demolition, this façade will likely shed bricks and debris, particularly during and following high wind events. At this time, no further demolition should be performed in this area and no demolition to the existing foundation system in this area should occur. The rubble and debris already on the ground in the vicinity may be cleaned up by the contractor. However, work should proceed very carefully and if high winds are forecasted, no work should be performed. Sincerely, DCI Engineers Matthew Hubbard, PE, Principal M O N TANA HUBBARD MATTHEW M. No. 15864PEP AION LOFES SR S REGI E N G INEERR E DTE