2018-1498_Doug's_Mazda_Service_Center_Struc_Beck_ARW Response 2_20190408.pdf
ARW Engineers ▪ 1594 West Park Circle ▪ Ogden, Utah 84404 ▪ Phone (801) 782-6008 ▪ Fax (801) 782-4656
MEMORANDUM
Project: Doug’s Mazda Service Center Project No: 18251
Location: Office Date: February 15, 2019
() Telephone ( ) Conference () Field (X) Memo
Memo by: Jordan Clark
Reviewed by: David L. Pierson, SE
RE: Doug’s Mazda Service Center – Beck and Associates, PLLC Review Comments
Gravity
2) Reference the Basis of Design noted on sheet S001. A floor live load of 50 psf is specified. However, a
live load of 60 psf is used for the design.
a) Provide coordination
b) In response to this item, the engineer references correspondence from February 4, 2019. In that
correspondence, we recommended that a minimum live load of 75 psf be used for storage, but
that the engineer would need to provide calculations that demonstrate that the anticipated load
(based on anticipated items stored and how they are stored) does not exceed 75 psf. These
calculations remain to be provided for our review.
Additionally, we indicate in response to the February 4, 2019 corresponde nce that the design live
load of the parts storage areas is required to be conspicuously posted in that part of each story
where the loads apply (60 psf at storage at existing construction; 75 psf at storage at new
construction). The plans need to specify this. 106.1, IEBC 402.3.1
The category in Table 1607.1 that most closely resembles the specified “Parts Storage” is
“Storage Warehouses” which identifies a ‘light storage’ live load of 125 psf. IBC 1607.2 indicates
that, for occupancies or uses not designated in Table 1607.1, the live load is required to be
determined in accordance with a method approved by the building official. Either design the new
Parts Storage for a live load of 125 psf OR provide 3etailed calculations for use of an alternate live
load that is consistent with auto parts storage. Revise the design as required.
ARW Response: See revised drawings and existing load calculation.
Lateral
3) The new & existing structures are shown to be integrally connected (no seismic joints are provided).
Reference details 5 & 6/S204. Additionally, reference comments in item 14, below.
a) The effective seismic weight is required to include a minimum of 25% of the floor live load for all
Parts Storage areas (whether existing or new). Revise the desig n accordingly.
b) The effective seismic weight is required to include contribution of any masonry or concrete walls.
The existence and extent of masonry and concrete walls were previously not clearly provided
within the drawings (either in the architectural d rawings or the structural drawings). Revise the
design accordingly.
ARW Engineers ▪ 1594 West Park Circle ▪ Ogden, Utah 84404 ▪ Phone (801) 782-6008 ▪ Fax (801) 782-4656
c) Identify all existing lateral force resisting elements that are being used to resist existing and/or
new lateral loads.
The effective seismic weight is required to include a minimum of 25% of the floor live load for areas used
as storage, such as for Parts Storage. Update the lateral analysis to consider this increase in seismic
weight. ASCE 7-10, 12.7.2
ARW Response: See revised calculations and drawings.
Drawing Sheets
S102 – Second Floor & Low Roof Framing Plan
12) The engineer will need to revise the diaphragm design to consider that the existing and new
structures share a lateral force-resisting system and to consider the required effective seismic weight.
Update the design accordingly. IEBC 403.4; ASCE 7-10, 12.7.2
Provide an analysis of the new diaphragm to trans fer loads to the shear wall located along grid G.
Reinforce the diaphragm as determined by the analysis.
ARW Response: See calculations.
S103 – Roof Framing Plan
14) In response to this item the engineer indicates that existing elements are not being utilized to
(laterally) support the Service Center Addition and that the new structure has been designed to be
laterally self-supported. However, seismic joints have not been provided between the existing structure
and the new structure. Reference details 5 & 6/S204. Where additions are not structural independent of
the existing structure, the existing structure and its addition acting together as a single structure are
required to be shown to meet the requirements of Sections 1609 (Wind) and 1613 (Earthquake). Revise
the design to either truly make the existing and new structures laterally independent (with seismic joints
designed per ASCE 7-10) or to consider them together as a single structure to resist lateral loads. Submit
calculations to substantiate the design for the chosen approach. Update design and detailing as required.
IEBC 402.4
Provide an analysis and detailing for transfer of lateral loads from the high roof (existing) into the new
roof diaphragm (along grids B & F) for transfer of loads to the shear walls along grids A & G. Provide a
complete load path. Additionally, where existing elements are being utilized, specify what those exist ing
elements are assumed to be and that they must be field verified.
ARW Response: Existing shear walls have been analyzed to include effective seismic weight for the floor loads.
Field verification will need to be performed by contractor to verify shear wall properties. Seismic and wind loads at
the roof will be supported by new shear walls. See revised drawings and calculations .
S201
16) In response to this item, the engineer indicates that the existing building consists of portions of
masonry walls, in which new door openings will be placed.
a) Update the plans to show the locations and extent of the locations of all existing masonry walls.
The plans must also indicate if the existing masonry walls are reinforced or not, and if they are,
what the reinforcement in the walls is.
b) The IEBC requires existing gravity load-carrying structural elements in which an increase in
design gravity loads of more than 5% occurs to be strengthened, supplemented, replaced, or
ARW Engineers ▪ 1594 West Park Circle ▪ Ogden, Utah 84404 ▪ Phone (801) 782-6008 ▪ Fax (801) 782-4656
otherwise altered as needed to carry the increased gravity load required by the IBC for new
structures. Additionally, any gravity load-carrying structural element whose gravity load- carrying
capacity is decreased as part of the alteration shall be shown to have the capacity to resist
applicable design gravity loads required by the IBC for new structures. Each existing masonry
wall needs to be assessed for increased loads (where new loads are applied to them) and for
decreased capacity (where being modified) to demonstrate compliance with these requiremen ts.
IEBC 402.3, 403.3
c) Unless the existing and new structures are laterally separated from each other with seismic joints,
and if existing masonry walls are used to resist lateral loads, the engineer will need to
demonstrate that the existing masonry (or concrete) walls meet the requirements for design of
new structures. Alternatively, the engineer will need to demonstrate that the demand/capacity
ratio of the structural element with the alteration is not more than 10% greater than the
demand/capacity ratio of the structural element prior to the alteration. Please note that unless
specifically seismically separated from the structure, the walls will need to be considered as part
of the lateral force-resisting system. Alternatively, they must be seismically separated from the
structure so that seismic loads are not imparted to them. Where no seismic separations are
provided, the lateral force-resisting system will need to consider horizontal and vertical
combinations of lateral force-resisting elements in accordance with ASCE 7-10, Ch. 12. IEBC 403.4
d) If there are unreinforced masonry walls in the existing structure, the alteration work is required to
include installation of wall anchors unless an evaluation demonstrates compliance of existing wall
anchorage. IEBC 403.6
Reference 4/S201. No masonry is specified on this project. Either identify the location where this detail is
applicable, or if not applicable, delete it from the drawing set.
ARW Response: See revised drawings and calculations. New openings in existing walls will be reinforced per the
revised drawings. The existing masonry wall along Grid 2 will not be supporting any new lateral load due to the
new addition. The total change in length of the existing wall will be reduced by approximately 1’-11”, therefore
meeting the provision that alterations account for less than 10% of the demand/capacity ratio.
S202
18) Reference comments in item 16, above.
Reference 2/S202. No masonry is specified on this project. Either identify the location where this detail is
applicable, or if not applicable, delete it from the drawing set.
ARW Response: See response above.
Copy to: Douglas Beck
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