Design Requirements

2018 Northern Nevada Code Amendments by the NNICC

Basic Wind Speed
1609.3 Basic wind speed (The ultimate design wind speed, V-ult' in mph)  Amend Section 1609.3 to read as follows:
 Table                   Table Notes:

  1. Air density corrections to design wind pressures are prohibited.    
   The conversions from Vult to Vasd are based on Table 1609.3.1                                                

Exception: Membrane structures intended to be in place for 30 days or less may be engineered to risk category l loads provided the installation and use are per the manufacturer's recommendations.

Seismic Design
I.B.C. Chapter 16, Section 1613 amended:
The seismic design for structures within Washoe County shall be based on the response parameters and equations of Chapter 16.  See ASCE 7-16 as referenced in the IBC.
I.R.C. Chapter 3 for single family residential structures: Use Category 'D2'.

Snow Load Requirements 
Step 1 - Click on the following link: Geographic Information Systems
Under Interactive Mapping Application heading, click on: Go To Quick Maps (Please note that Map Warehouse is no longer available).
If you agree with the disclaimer, click on: "I agree" at the bottom
You can then enter the property location either by address or assessor parcel number in the upper right had corner.
When map of the property appears, click on: Show Layers tab to the right, then go to menu on right side and click on the 2 foot contours.  Zoom in to get elevation number shown on your map/parcel
If no 2-foot contours show up, Washoe County does not have accurate elevations for your site.  Go back down list and click on 10 Meter USGS Contours.  USGS topo maps may help you to determine your property's elevation.  Please consult your designer.  A Nevada registered surveyor can also determine your property elevation.

Step 2 - Once you determine the datum elevation of your property, use the following table to determine the design snow load.
1608.2 Ground Snow Loads Amend Section 1608.2 to read as follows:
The ground snow load to be used in determining the design snow loads for roofs shall be determined in accordance with Table 1608.2.1:

Table 1608.2.1

Note:  This table refers to the old Hwy 395

Ground Snow Loads pg , For Northern Nevada Locations  

1. Drift load design  in the 30 psf zones may utilize ASCE 7-16 table c7-1 ground snow values. 2. The final roof design loads shall not be less than 20 psf after all reductions are factored, except for Lyon & Storey Counties. 3. Intermediate values may be interpolated by proportion.

Frost Lines, Footings & Foundations
1809.5  Washoe Counties and the Cities of Reno and Sparks shall be twenty-four inches (24") deep.Frost Lines Table

 1808.6.1 Foundations.

Amend Section 1808.6.1 to read as follows:

1808.6.1 Foundations. Foundations placed on or within the active zone of expansive soils shall be designed to resist differential volume changes and to prevent structural damage to the supported structure.  Deflection and racking of the supported structure shall be limited to that which will not interfere with the usability and serviceability of the structure.

Foundations placed below where volume change occur or below expansive soil shall comply with the following provisions:

  1. Foundations extending into or penetrating expansive soils shall be designed to prevent uplift of the supported structure.
  2. Foundations penetrating expansive soils shall be designed to resist forces exerted on the foundation due to soil volume changes or shall be isolated from the expansive soil.
Post-tensioned slabs shall not be utilized in place of frost depth footing design unless super structure deflection and differential movement calculations are provided. The deflection calculations would need to show that the maximum combined frost and expansive soil heaving, as localized at slab edges, with resultant non-uniformly distributed deflections, as well as whole slab deflections would not result in super structure racking or excessive truss, roof or wall frame movement.
 

 

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