Structural Engineering Standards

Review Design Standards General Statements before utilizing this web page.

Executive Orders (EOs)
Building Codes & Industry Standards
National Park Service (NPS) Requirements
Professional Guidance



Executive Orders (EOs)

Building Codes & Industry Standards

  • IBC 2015
  • IEBC 2015
  • ASCE 7-10
  • ACI 318-14
  • ACI 301-10
  • ACI 530-13
  • AISC Steel Construction Manual, 14th edition
  • AISC 341-10 Seismic Provisions for Structural Steel Buildings
  • NDS-2015
  • AITC Timber Construction Manual, 6th edition
  • AFPA SDPWS-2008

National Park Service (NPS) Requirements

Denver Service Center (DSC) Requirements

Load Requirements

  • Floor Live Load: IBC 2015
  • Roof Live Load: IBC 2015
  • Snow Load: IBC 2015 as required for building location, with consideration of:
    • Unbalanced snow load
    • Snow drifting at lower roofs and projections
    • Roof valley snow drifting
    • Sliding snow
  • Wind Load: ASCE 7-10 as required for building location
  • Seismic: ASCE 7-10 as required for building location
  • Vehicle Bridges: HS20
  • Pedestrian Bridges and Boardwalks: 85 psf


  • Frost Depth: As required for building location


  • Concrete shall be assigned an Exposure Category per ACI 318, Table
  • Concrete mix designs shall not exceed paste volume of 25%.
  • Minimum slab-on-grade thickness 4" at thinnest point (typically at floor drains)
  • Minimum compressive strength at 28 days: as required by design, but not less than 3000 psi
  • Minimum 15% flyash content
  • Reinforcing steel: ASTM A615 Grade 60
  • Provide control joints and/or adequate reinforcing steel at re-entrant corners in slabs-on-grade.
  • Use of staggered or offset control joints in slabs-on-grade is not permitted.
  • Use ACI 360R-10 for slab-on-grade design.


  • Concrete masonry minimum f'm: 1500 psi
  • Reinforcing Steel: ASTM A615 Grade 60
  • Below grade walls and retaining walls grouted solid.
  • Provide control joints near building corners and as recommended by NCMA 10-2B.


  • W Shapes: ASTM A992, Fy = 50 ksi
  • S, M, C and MC Shapes: ASTM A36, Fy =36 ksi, or A572 Grade 50
  • HP Shapes: ASTM A572 Grade 50
  • Angles, Plates and Bars: ASTM A36, Fy = 36 ksi, or A572 Grade 50
  • HSS (Rectangular): ASTM A500 Grade C, Fy = 50 ksi
  • HSS (Round): ASTM A500 Grade C, Fy =46 ksi
  • Steel Pipe: ASTM A53 Grade B, Fy = 35 ksi
  • Bolts: ASTM F3125 Grade A325 or Grade A490
  • Nuts: ASTM A563
  • Washers: ASTM F436
  • Anchor Rods: ASTM F1554 Grade 55
  • "L" and "J" shaped anchor rods shall not be used to resist tension.
  • Weld Electrodes: FEXX = 70 ksi


  • Minimum roof sheathing thickness: 5/8"
  • Minimum wall sheathing thickness: 1/2"
  • Framing Lumber (depending on location, availability, and structural requirements)
    • Southern Pine No.2 or better
    • Hem Fir No.2 or better
    • Douglas Fir Larch No.2 or better
  • Provide blocking between roof framing members at bearing locations and at diaphragm boundaries.
  • Provide plywood or OSB sheathing over heavy timber decking to create a diaphragm.
  • Whenever possible, engineered lumber (Glulams, LVL's) shall be used in lieu of solid sawn members 8x8 and larger.
  • Use of pentachlorophenol pressure treatment for glulams is not acceptable.

Professional Guidance


Coastal/Marine Construction

Seismic-Existing Buildings

  • ASCE 41-13 Seismic Evaluation and Retrofit of Existing Buildings

Tornado Shelters