Loading...
HomeMy WebLinkAboutInspection Report 08.13.13Studio M Engineers, LLC Structural Engineering Consultants August 13, 2013 Innovation By Perception www.mbengi neering.elementfx.corn micbaca@yahoo.com Richard Collins 100 Williams Ranch Road Aspen, Colorado 81611 Re: 4501 County Road 233, Rifle Colorado, Permit No, BLCO 4-13-2805 Per your request my office was asked to inspect the prefabricated metal building at the previously mentioned address. The reason for the inspection was to identify any possible structural issues associated with a change of occupancy type and the proposed remodel. It is my understanding that the proposed occupancy will be type F1, or moderate hazard factory industrial group per IBC 2009 section 306,2 Per the written comments on the drawings for permit, the county has requested that I verify the structural compliance of the following items in light of the proposed occupancy change and remodel. • building alterations • partition walls • storage loft • metal building lateral cables • metal building assemblies supporting electrical and mechanical equipment PROJECT DESCRIPTION: 4501 County Road 233 is a prefabricated metal building located between farm land parcels north of Silt at the edge of an agricultural field. The site elevation is approximately 5,575 feet above sea level. The perimeter of the building measures 30'x60' with a roof elevation of approximately 12'. The building was constructed in 1999 by a company called Sunward Corporation, now known as Gold Seal Steel Buildings, based on information found on site. The building is divided into a workshop space on the West, with several partitioned rooms on the East. The rooms have a ceiling at an elevation of approximately 7'-4" above the slab, with a loft area between the metal building roof and the partition ceilings. Remodel Plans: A set of plans outlining the proposed remodel and change of use was available on site during my inspection. The plans were produced by the PBR Workshop of Aspen. The architect name on the plans is Ron Mazzeo of Salida; the plans are dated August 9, 2013, job number 13119. • 308 N. Hyland Park Dr. • Glenwood Springs • Colorado • 816o1 • 97o-366-8690 4501 County Road 233 Page 2 Original Building Information: A letter from the Sunward Corporation dated February 22, 1999 indicates that the building was designed for a roof snow load of 40 psf. The project is identified as number G21570E. Metal Building Foundation: The foundation appears to be an 8" thick concrete stem wall. No foundation reinforcement was visible at the time of inspection. The only visible area of foundation was at the garage door threshold, on the West. I would assume the wall extends down past frost depth to a footing of adequate size. A roughly contoured slab on grade covers the floor in the area of the partition walls. No slab exists in the area of the workshop. The floor and foundation is covered with a gravel fill. Metal Building Framing: The metal building consists of four tapered steel frames. The frames are located at the building ends, and the interior quarter points (20' on center). The frames support a series of Z-girts spanning East-West. The Z girts exist on both the roof and the walls. Spacing of the roof girts was approximately 5'-0" on center. The girts on the walls are partially obstructed from view by wood sheathing. OBSERVATIONS: A system of mechanical and electrical apparatuses is suspended from hooks that are fastened into the wide face of a series of Hem Fir stud grade 2x4 supports. The 2x4 supports span in the North South direction, perpendicular and below, the Z girts at a spacing of approximately 8'-0" on center. The 2x4's are attached to the Z girts with a single fastener at each intersection point. The mechanical and electrical systems are suspended from the hooks above with wire at a height of approximately 5' above the gravel floor. The systems are fabricated from thin walled sheet metal or aluminum. My estimate of the mechanical -electrical system weight is in the range of 3-4 psf. In other locations, mechanical ducting was suspended from the same 2x4 system. Partition Walls: The partition walls can be categorized as new and existing. The new walls were added around the current tenant's water tank on the South interior of the building. The existing walls had been added by the current property owner at a previous date. Walls in both areas are typically 2x4 construction with studs at sixteen inches on center. Partition Wall Ceiling: Ceiling joists at the existing partitions consist of 2x8's at sixteen inches on center. Ceiling joists at the new partitions are 2x4's at sixteen inches on center. The joists are covered with a system of 1/z" thick sheathing. The 2x8's span a maximum length of 13'-2". The joists form the ceiling of the rooms as well as the floor of the loft above. Ceiling and partition construction at the new area by the water tank is unconventional with a variety of framing and connection anomalies. • 308 N. Hyland Park Dr. • Glenwood Springs • Colorado • 816m • 97o-366-8690 4501 County Road 233 Page 3 Metal Building Cables: The cables provided by the metal building manufacturer as the primary lateral system of the structure have remained unaltered. No equipment was attached to the cables at the time of my inspection. Cables exist in both the walls and the ceiling. CONCLUSIONS: The building alterations at 4501 County Road 233 appear to be minimal from a structural standpoint. The concrete slab supporting the partition walls is of such quality and finish as to assume that the primary purpose is a floor covering. Foundation support from this slab is considered minimal. The metal building lateral cables appear to be unmodified and performing as originally intended. The metal building assemblies supporting the electrical and ventilation equipment are capable of supporting these systems in combination with the anticipated design loads required by Garfield County. The design loads for this structure are: • 40 psf, roof snow load • 5-10 psf roof dead load • 90 mph Exposure C allowable stress design wind load Data provided by the 2007 SEAC Colorado Ground Snow load study indicates that after 87 years of statistical data, the maximum anticipated snow load in the Rifle area has been approximately 20 pounds per square foot. This value is significantly lower than the snow load the building was designed for (40 psf roof). The added weights of the tenant's mechanical and electrical systems are considered within the system abilities, especially in light of the apparent factor of safety in the Garfield County snow load requirement. The only change in load associated with the occupancy change would relate to the gravity system of a structural floor. The current construction is either gravel or slab on grade, leading to the conclusion that the change of occupancy will have no effect on the floor level loading of the building. RECOMMENDATIONS: 1 would recommend that the existing loft be used for minimal storage, with loads not exceeding 15 pounds per square foot. Individual items such as air compressors and other mechanical units, should not exceed 150 pounds per unit and should be positioned in such a way as to not exceed the 15 psf value. The area above the new partition walls around the interior water tank should not be used for storage. The framing should be supported in a more conventional manner with the • 308 N. Hyland Park Dr. • Glenwood Springs . Colorado • 81601 • 97o-366-8690 4501 County Road 233 Page 4 installation of a continuous 2x4 ledger installed tight to the under side of the existing joists (west. The ledger should be fastened to the studs with 2-#10 x 3" screws per stud. On the east, the double 2x4 ledger that currently supports the ceiling joists should be adequately fastened to the existing wall with a minimum of (2) 1/4' diameter lags (5" length) per stud. The joists should be toe nailed to the ledger with (2) 16d toe nails per joist. Existing Grade: Based on conversations with the owner, I understand that the water table at the site can be seasonally high. Satellite imagery indicates that the building was constructed on an agricultural site that has experienced irrigation for years. Previous wetting in light of the proposed loading would lead to the conclusion that future settlement risk would be low, even in the presence of minimal amounts of water at the bearing soil level. Despite this conclusion, it is still recommended that the grades slope away from the building in an effort to keep positive drainage away from the foundation. The seasonal growth and decay of the vegetation around the building has begun to elevate the exterior grade above the level of the top of the foundation wall, especially in the West. I would recommend that the vegetation within 10' of the building be maintained in an effort to slow the effects of natural grade change as a result of organics accumulation. LIMITATIONS: The scope of my inspection was limited to the investigation of the following items: • Structural evaluation of the existing and new partition wall framing systems • Structural evaluation of the existing storage loft • Inspection of the existing metal building lateral cable system. • Structural evaluation of the additional weight of the mechanical -electrical systems on the metal building structure • Investigation into the loading requirements that are a result of the change of occupancy My inspection did not include analysis or conclusions regarding the attachments, fasteners and 2x4 ceiling support system for the tenant's mechanical and electrical systems. These items are considered a separate system that is beyond the scope of this report. The areas that I observed were readily accessible using conventional means of access and observation. Modifications to the mechanical and electrical systems that produce a load over 4 psf of assembled components will invalidate the conclusions in this report. Such changes should be reviewed by my office before they occur. • 308 N. Hyland Park Dr. • Glenwood Springs • Colorado • 81601 • 97o-366-8690 4501 County Road 233 Page S Likewise, framing and structural system deficiencies that were hidden behind finishes or obstructed from readily available points of visible access may exist, and would similarly invalidate the conclusions in this report. Such anomalies should be reported if they are discovered. My site visit does not make my company responsible for warranting or approving (expressed or implied), directing or superintending the work, means or methods of work, safety in, on or near the work site, timeliness in performance of the work, nor any other aspect of construction for which the owner and contractor(s) have responsibility. The site visit was for assessment and observation and does not relieve the owner and contractor(s) of the responsibilities for performing the work in accordance with the project plans and specifications. The statements or lack thereof, made during the site visit do not express or imply code compliance with systems beyond the scope of work identified in this report. This concludes this report. Please contact my office with any questions or comments. Sincerely, Michael J. Baca, P.E., NCEES Principle Structural Engineer cc: aspenbubba5@msn.com • 308 N. Hyland Park Dr. • Glenwood Springs • Colorado • 81601 • 970-366-8690