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HomeMy WebLinkAboutFile Documents.835 E Hyman Ave.0064.2018 (4).ARBK PATTILLO ASSOCIATES ENGINEERS, INC. STRUCTURAL CONSULTANTS 1215 grand avenue,post office box 751 glenwood springs,colorado 81602 phone(970)945-9695 e-mail:info@paengineers.com paengineers.com July 24, 2017 Hy-West Condominium Association c/o Cheryl Schmidt, Property Manager P.O. Box 2768 Aspen,CO 81612 Re: Hy-West Condominiums Roof Structure Evaluation Ladies and Gentlemen: Personnel of Pattillo Associates Engineers have completed an initial investigation of the existing roof framing at the Hy-West Condominiums at 835 East Hyman Avenue in Aspen, Colorado. We understand that the roofing and roof insulation is planned to be replaced in the near future,and the existing structure needs to be evaluated for its capacity to carry snow loads in accordance with current Aspen building code criteria. Our findings,conclusions, and recommendations are included herein. Building Description/Observations: Originally built in 1969,the building is a two-story multi-family housing complex constructed of light wood framing. As-built drawings are not available,thus the structural composition was determined solely by site investigation along with information provided by the resident property manager. The complex is laid out roughly in an 'L' shape with the two wings connecting at the southwest corner, one wing extending to the north and the other extending to the east. These will herein be referred to as the North Wing and East Wing,respectively. The roof structure consists of 2x6 tongue-and-groove decking on 4x12 full-sawn beams, which appear to be No. l Douglas Fir-Larch based on visual inspection of the framing in one of the units where the beams were sanded and not painted or covered by finishes. The roof is a gable style with a 2:12 pitch and beams are spaced about 4'-2" on center. The wall framing was not exposed to view, but it is assumed that the bearing walls were built of 2x4 studs as it was a popular method of construction for many buildings erected in Aspen at that time. The beams span 17 feet from wall to wall in the East Wing and 14 feet 6 inches in the North Wing. In both wings,the tails of the beams cantilever to overhang the deck area by 7 feet 6 inches. The floor framing was covered with finishes,thus could not be observed; furthermore, it was not included within the scope of this investigation. Analysis: The snow load capacities were calculated for the roof decking and the roof beams in each wing. Wood design stress values were obtained from, and capacity computations were performed in accordance with, the National Design Specification for Wood Construction (NDS) and Supplement, 2015 editions. RECEIVED 04/02/2018 ASPEN BUILDING DEPARTMENT Roof Evaluation at Hy-West Condominiums July 24, 2017 Page two Snow load capacities in pounds per square foot(psf)were calculated to be as follows: 2x6 roof decking 316 psf East Wing roof beams, north of ridge 39 psf East Wing roof beams, south of ridge 37 psf North Wing roof beams, east of ridge 48 psf North Wing roof beams, west of ridge 60 psf The minimum required ground snow load as prescribed by the City of Aspen Municipal Code is 100 psf. This equates to a design roof snow load value for this building of 100 psf as specified per Minimum Design Loads for Buildings and Other Structures,2010 edition (ASCE 7-10), Unbalanced Roof Snow Loads section. This design value is the minimum required snow load to which the snow capacities of the existing roof elements are to be compared. Please be aware that the north side of the East Wing and the east side of the North Wing include the cantilevered roofs over the access decks. Conclusions: The 2x6 roof decking is more than adequate to support any snow loading that may occur at the site. The roof beams are not adequate to support the minimum required snow load criterion. The East Wing has a lower snow load capacity than the North Wing, due to larger beam spans. Remedial action, as outlined in the recommendations section, is required to reduce the stresses experienced by the roof framing in these areas during periods of heavy snowpack accumulation. Recommendations: The following are the minimum remedial actions we recommend be performed based on the previous discussion: Excess snow from the roof should be removed periodically as required. The least snow load capacity given in the analysis section(37 psf)was converted to an approximate snow depth using criteria in accordance with Appendix 1 of the 2016 Colorado Design Snow Loads manual by the Structural Engineers Association of Colorado (SEAC). According to these data, we recommend monitoring the snow depth at the roof level and clearing excess snow when the depth exceeds 24 inches. Depth readings should be made approximately 2 days after any snowfall that deposits a significant amount of precipitation, so that"settled" snowpack depths are measured rather than fresh snow depths. Limitations: Our inspection of the property was limited to structural conditions as described; no destructive or intrusive inspections were conducted. No analyses or other evaluations were made to verify design or as-built compliance with building codes or other standards. No other documents or drawings were provided for our review. We assumed RECEIVED 04/02/2018 ASPEN BUILDING DEPARTMENT Roof Evaluation at Hy-West Condominiums July 24, 2017 Page three adequate support exists for all roof system elements. If additional information becomes available or if other conditions are discovered, our opinions are subject to change. This completes our report. Please contact us if you have any questions. sos Sincerely, Reviewed by, �41 0Q'PpM,p�CF,I, Uip CO: d 16794 0: Brian Rossiter,P.E. Robert M. Pattillo, P.E. ass/pNAI FNC►,�' Project Engineer Principal Engineer email copy: Cheryl Schmidt (cschmidt a.rof.net) RECEIVED 04/02/2018 ASPEN BUILDING DEPARTMENT