2106 EVERETT AVE 2019-01-28 - Laserfiche WebLink

Mr. John Day Slichter Ugrin Architecture Plan Check Number: B1709-015, First Review April 27, 2018 etail 9/S2.1 specifies Simpson "BA"hangers for the wood joists. See IBC Section 107.2.1. Th following comments should be addressed: The size of the hanger should be specified. 6 The hangers will be welded to the channels. However, the existing sheathing is to remain in-place. Clarify how the work will be performed. . Revised calculations for the design of the roof framing supporting the parapet bracing should be submitted for review. See comments below regarding the wind pressures. The calculations should include a key plan clarifying the members being evaluated. The loads from the bracing are concentrated on the joists, and therefore the joists should not consider the repetitive member factor Cr per NDS-15 Table 4.3.1. See IBC Sections 1604.1 and 2306.1. The following minimum locations should be included in the calculations: a. Joists parallel and perpendicular to the bracing that provide direct support. Note that joists in the building corners are concurrently subject to both conditions. b. Joists supporting back-span ends of joists providing direct support. c. Exterior cantilever ends of existing framing that support joists providing direct support. C The roof framing plan on Sheet S2 specifies multiple existing built-up beams to be strengthened with C10 beams per Detail 9/S2.1. The C10 beams effectively replace the existing beams, but will rely on the existing beams for end bearing on the existing supports. Calculations substantiating the existing beam ends to transfer loads to the supports should be submitted for review, including but not limited to: end shear, end flexure, crushing at the end thru-bolt, bolt shear, and bearing on the support. Note that a single bolt provides the primary shear transfer at the ends, and the bolt placement is staggered along the length and vertically. The capacity and detailing check for the bolt capacities and detailing shall consider the most severe position of the bolt in the beam depth. See IBC Sections 1604.2 and 1604.4. • 1,(6 711/1/4 1f iJ$ Lateral System: .-J/o & t I'7✓� ri'O eak-r et�•o-�t_‘6o,o/0f7 ge 2 of the structural calculations provides the design wind pressures for the parapet design. The wind pressures should be revised based on the following comments. The structural design may need to be revised. See IBC Section 1609.1. The exposure adjustment factor (EAF) appears to be based on a height of 15 feet per ASCE 7-10 Table 30.7-2. The factor should be EAF=0.692 for a maximum parapet height of approximately 20 feet per the elevations on Sheet A4.1. j ?The windward and leeward pressures appear based on a maximum height of 15 feet. Design pressures, including the roof pressure considered for the windward pressure, shall be based on the maximum parapet height of 20 feet. See ASCE 7-10 Section 30.7.1.2 and /The figure 30.7-1. • windward and leeward parapet pressures shall consider positive and negative pressures on each side of the respective parapets per Figure 30.7-1. Based on Table 30.7- 2, the windward and leeward pressures appear to be at least 105.9 psf and 72.6 psf, respectively. dhe calculations for the design of the framing and connections should be revised using the required wind pressures. The windward and leeward pressures should should be applied in the applicable directions for all portions of the structure to develop the maximum load effects. —Page-3-ef-5 CITY OF EVERE1T• 3200 Cedar Street • Everett,WA 98201 • (425) 257-8810 • Fax(425) 257-8857 1-