Please provide foundation drawings stamped by an Engineer licensed in Alaska as required by the Alaska State Statutes section 08.48.221.
Comment resolved. Stamped drawings have been provided. WAB – 12/8/2014
Please provide a foundation under the window system that is frost protected per IBC section 1809.5. It must be clarified whether this new enclosed area is heated or not as well as the frost protection requirements are different for heated and unheated structures.
Comment resolved. Per the Owner there is in floor heating so the foundation provided previously should be okay. WAB – 12/8/2014
Please provide a complete set of window wall drawings showing the construction of the window wall system including connections to the existing structure and connections to the foundation. These connections must be designed to resist the required wind loads. Reference AAC section 23.10.104.8 and IBC section 1605.
Comment remains. No response provided. This item can be deferred per AAC section 23.10.104.9. WAB – 12/8/2014
Comment resolved. This is deferred. WAB – 12/18/2014
The wind area at the addition of these elements has been increased. Please provide substantiating data showing the demand capacity ratio of any existing lateral element has not been increased by more than 10% or where it has show that it meets current code requirements. This also applies to the seismic loads. Reference IEBC section 303.4.
Comment resolved. Based on the size of this structure it is likely that it was not wind controlled, and even if it was the wind load at the base would be large compared to the amount added by the addition of walls at this canopy. WAB – 12/8/2014
DESIGN OF COLUMNS
Reference pages 12-14 of the calculations and sheet S2.0 of the drawings. Please clarify the design of the existing columns. They are shown as round HSS and per discussion with the owner they are round; however the design provided is for an HSS6X6X1/2. Also the design of the columns has been for a fixed-pinned condition. This needs to be modified to a fixed-free condition with an effective length factor, K, equal to 2.1. Please note that the calculations are very confusing in regard to the design of these columns. The seismic load appears to be indicated as 25.3/31*(13/2+11/2) which doesn’t appear to be correct. It appears it should be [(15.75/2+13/2)/(25.3/31)]/2 = 5.87 kips. Since it’s possible that this structure will have an extreme torsional irregularity rho must be verified as 1.0. Otherwise used 1.3 as required by ASCE 7-05 section 12.3.4.
Comment resolved; however please note for future submittals that iIn the case of moment frames, the effective length factor would be determined using the nomograph in AISC 360-05 figure C-C2.4 or using the equation for sidesway uninhibited shown on page 16.1-240. It appears that this value is less than the 2.1 used in the design though. WAB – 12/18/2014
DESIGN OF ANCHORS AT EXISTING COLUMNS
Reference pages 9 through 13 from permit C13-2088 (Schneider job #213187) and the current design. The shear loads from the current design far exceed the previous shear load. The dead load under the current design does appear to be ultra conservative. Please note that the concrete pullout strength from the previous submittal appeared to be 92% stressed, and that a ductile steel element did not appear to control the design of the anchor (no non ductile yielding factor appeared to be applied either).
Comment resolved; however see additional comments generated. WAB – 12/18/2014
DESIGN OF EXISTING BEAM B3
Reference pages 34-35 of the calculations. This beam has been design as fully braced against lateral torsional buckling. Please verify that this is the case as there doesn’t appear to be anything bracing the top of this beam. Please verify that fy is 50 ksi as well. Reference AISC 360-05 section F2.2.
Comment resolved. This beam has been redesigned. WAB – 12/18/2014
SPECIAL INSPECTOR LETTER
Please provide a letter from the Owner indicating who they will be hiring to provide special inspections for this project.
Comment resolved. This has been provided. WAB – 12/18/2014
MOMENT FRAME CONNECTIONS
Reference pages 80 through 86 of the calculations. Please verify the loads used to design the moment connections. AISC 341-05 section 11.2a requires moment connections to be designed for 1.1*Ry*Mp of the column or beam whichever is smaller or for the maximum force that can be transmitted by the system. Per the commentary the maximum force that can be developed by the system can be taken as the seismic force using an R=1.
Please provide a written response to the comments and include one copy of additional or revise calculations, and two copies of additional or revise drawings.
Reviewed by: Bolen, Wayne A. Permit #: C14-1960
Phone: 343-8072 Date: 12/18/2014
Fax: 249-7393
Email: BolenWA@muni.org
Permit Manager: Tony Barganier
Phone: 343-8339
Email: BarganierTA@muni.org
Project: Inlet Tower Canopy
Review Number: 344709
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PERMIT STATUS
10/13/2014 – Review complete. Comments issued.
12/8/2014 – Responses reviewed. Comments issued. Please note that the scope was not clear on the original submittal. The scope reviewed was to add a window wall system around an existing canopy. The scope now is to rebuild the canopy roof and add a window wall system. Additional comments have been generated because of this.
12/18/2014 – Responses reviewed. Comments issued.
All submittals should be sent to the permit manager.
