POST-FRAME BUILDINGS: A LIGHT-COMMERCIAL

MAINSTAY

Copyright © 2011 National Frame Building Association

CONTINUING EDUCATIONThe National Frame Building Association is a Registered Provider with The American Institute of Architects Continuing Education Systems.

This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

“With so many structural framing options, building functions, and architectural finishes, post-frame building systems are limited only by the architect’s imagination and creativity.”—Harvey Manbeck, PE PhD, professor emeritus at Penn State University and NFBA technical advisor

Photo courtesy of Kistler Buildings Photo courtesy of Wick

“Post-frame contributes very well to both the environment and the value for your dollar.”

—Cheryl Ciecko, ALA AIA LEED AP CSI GGP, technical director, WoodWorks, a nonprofit initiative of the Wood Products Council

Photo courtesy of Lester Building Systems, LLC Photo courtesy of Fingerlakes Construction Company

• Versatility and range of applications

• Structural features that make these systems unique

• Key performance characteristics • Resources for designing post-frame building

systems

LEARNING OBJECTIVES

Photo courtesy of Morton Buildings

Many architects and design professionals are unfamiliar with post frame.• It is not commonly included in traditional architectural

school curricula.• They incorrectly equate post-frame construction with

post-and-beam construction• They think post frame is only for agricultural buildings

(i.e., barns, storage facilities, or horse facilities).

WHAT IS POST FRAME?

POST FRAME IS EVERYWHERE

Photo courtesy of Lester Building Systems, LLC

CONVENIENCE STORES

Photo courtesy of Lester Building Systems, LLC

Photo courtesy of Fbi BuildingsPhoto courtesy of Wick Building

RESTAURANTS

Photo courtesy of Fbi Buildings

COMMERCIAL OFFICE AND VETERINARY CLINICS

Photo courtesy of Morton Buildings

Photo courtesy of Morton Buildings

RELIGIOUS SPACES

Photo courtesy of Wick Buildings

PRIVATE HOMES

Photo courtesy of Morton Buildings

PUBLIC BUILDINGS

Photo courtesy of Morton Buildings

Photo courtesy of Lester Building Systems, LLC and SL Construction

COMMUNITY BUILDINGS

Photo courtesy of Little Construction Co., Inc.

Photo courtesy of Kistler Buildings

RECEPTION HALLS

Photo courtesy of Lester Building Systems, LLC and Eastern Iowa Building, Inc.

Photo courtesy of Lester Building Systems, LLC and Eastern Iowa Building, Inc.

RETAIL STORES

Photo courtesy of Lester Building Systems, LLC

POST-AND-BEAM CONSTRUCTION

Continuous Footeror Pier Foundation

PostPinned Connection

Girder (Beam)

Floor

Concrete Pier

POST-AND-BEAM CONSTRUCTIONPost

Girder (Beam)

Purlin

THIS IS POST FRAME

Figure 1. Post-frame building with trusses supported by embedded posts

Primary frames

Wood ColumnClear span truss

Embedded Post Foundation

Truss-to-Post Connection

THIS IS POST FRAME

Figure 2. Post-frame building mounted on a concrete stem wall

Roof Purlin

Wall Girt

PRIMARY FEATURES OF POST FRAME

Wood columns

Truss

Purlins

Sheathing

Wall girts

PRIMARY FEATURES OF POST FRAME

THIS IS POST FRAME—PLAN VIEW

Purlin

Post

Girder (Header)

Clear Span Truss

KEY FEATURES OF POST FRAME

Eave Height Post Height

Clear Span

X-section

Post Footing

Post Foundation

Sidewall Post

TrussPurlins

Girts

Splashboard

• wood sidewall columns • wide bay spacing—8 ft and greater• large clear spans—over 100 ft • embedded wood columns or concrete piers• attached wall and roof sheathing or cladding

form structural shearwall/structural diaphragm system for resisting lateral loads

KEY FEATURES OF POST FRAME

• Solid-sawn, glued-laminated, or mechanically (nail) laminated wood

• Nominal 6x6, 6x8, 8x8, or 8x10 cross section• Typically spaced 4, 6, 8, 12, or 16 ft on center

along sidewall• Any portion of the wood post embedded directly

into the ground and 6–12 in. above grade is pressure preservative treated to AWPA-recommended levels for ground contact

WOOD SIDEWALL COLUMNS

Spliced glued-laminated column• 3- or 4-ply, fabricated

with 2x lumber• lower portion is

preservative treated• upper portion is

untreated

WOOD SIDEWALL COLUMN

WOOD SIDEWALL COLUMNS

Nail-laminated posts with treated bottom spliced to untreated top

Preservative-treated splash board

WOOD SIDEWALL COLUMNSUntreated Post

Concrete Pier

PRESSURE PRESERVATIVE TREATMENTS

• Posts embedded in the ground, specify:

• use category UC4B or better per AWPA-U1-09

• e.g., CCA@0.60 pcf

POST FOUNDATION OPTIONS: EMBEDDED TREATED COLUMNS

Treated

PRECAST OR CAST-IN-PLACE REINFORCED CONCRETE PIER

• Pre-cast reinforced concrete pier with post attached above grade

• Entire assembly pre-engineered

• Assembly usually fabricated in factory and shipped to site as a single unit

PRE-CAST REINFORCED CONCRETE PIER

Reinforcement

Cleat

CAST-IN-PLACE CONCRETE FOUNDATION WALL

Untreated Post

Connection Hardware

Cast-in-Place Concrete Foundation Wall

THICKENED CONCRETE SLAB

THICKENED CONCRETE SLAB

• Blow-molded plastic or HDPE plastic protective barriers

• Provide moisture and insect protection

• “Enhance protection of copper-based chemical treated wood posts or laminated columns”

PROTECTIVE POST COVERS

• Pre-engineered metal plate connected 2x lumber trusses typically spaced 4–8 ft on center

• Heavier timber trusses for larger post and truss spacings and aesthetic requirements

• Solid-sawn wood rafters spaced 2–4 ft on center for shorter clear spans

• Glulam rafters for larger rafter spacings or clear spans

ROOF FRAMING

ROOF FRAMING

Trusses

Sidewall Post (connected to trusses)

• Posts are connected directly to the roof framing if post and roof framing spacing are the same

• Posts and roof framing are often connected to header beams if post and roof framing spacing are not the same

POST TO ROOF FRAMING CONNECTIONS

POST TO ROOF FRAMING CONNECTION

Block Height

Block

Connection is usually a pinned connection (not a moment-resisting connection).

POST TO ROOF FRAMING CONNECTION

POST TO ROOF FRAMING CONNECTION

SOLID SAWN POSTS

1½”Connection with truss fastened to slide of post and with bear block

Connection with truss bearing on notch in post

Typical post to truss connection details for a solid sawn post application

POST TO ROOF FRAMING CONNECTION

• Schematic of typical connection details

• Truss to header (girder)

• Header (girder) to roof

POST TO ROOF FRAMING CONNECTION

Metal Plate Connector

Header (Girder)

Blocking

ROOF PURLIN PLACEMENTPurlins oriented flat or “on edge,” depending on truss and purlin spacing

Purlins placed either on top or inset between truss top chords or inset between roof rafters

ROOF FRAMING AND PURLINSTrussPurlin

2 ft o.c.

Connection to Post Connection

8 ft o.c.

• Typically 2x4 to 2x8 solid sawn lumber, spaced 24–32 in. apart

• Oriented “flat” on outside face of wall post for smaller post and girt spacings and loads

• “On edge” between adjacent posts for larger loads or post or girt spacings

WALL GIRTS

WALL GIRTS AND SHEATHING

Wall Girt

Sheating

WALL GIRTS AND SHEATHING

SECONDARY FRAMING AND BRACING

• Corner bracing in upper chords of trusses• Diagonal bracing for lower chords of trusses• Lower chord stiffeners for trusses• Cross bracing of selected compression webs• Continuous longitudinal bracing of long

compression webs and chords of trusses

• Guide to Good Practices for Handling, Installing, Restraining & Bracing of Metal-Plate Connected Wood Trusses (WTCA and TPI)

• B1 and B3 summary sheets: handling and bracing trusses

• B10 summary sheet: Post-frame truss installation and bracing

TRUSS BRACING

The most economical combination has• laminated wood sidewall and endwall columns• embedded post or embedded concrete pier

foundations• metal-plate connected 2x wood roof trusses and• 26- to 29-gauge ribbed steel roof and wall

sheathing

UNIQUE FEATURES OF PF

• ANSI/ASAE (ASABE) EP 484 for diaphragm design of metal-clad, post-frame rectangular buildings

• ANSI/ASAE (ASABE) EP 486 for shallow post foundation design

• ANSI/ASAE (ASABE) EP 559 for design requirements and bending properties for mechanically laminated columns

PF TECHNICAL RESOURCES

• Structural design proceduresfor PF building systems– PF designer’s primary

reference– www.NFBA.org

PF BUILDING DESIGN MANUAL

• Cost-effective• Energy efficient• Code compliance• Sustainability and greenness• Design flexibility • Durability and strength

BENEFITS OF POST FRAME

• National Frame Building Association (NFBA)

• www.PostFrameAdvantage.com • www.NFBA.org• NFBA

8735 W Higgins Road Suite 300

Chicago, IL 60631

MORE ABOUT POST FRAME

• National Frame Building Association (NFBA)

• www.NFBA.org• www.PostFrameAdvantage.com • NFBA

8735 W Higgins Road Suite 300

Chicago, IL 60631

QUESTIONS AND COMMENTS?

PREPARED BY HARVEY B. MANBECK, P.E., PHD

PROFESSOR EMERITUS PENN STATE UNIVERSITY

COPYRIGHT @ 2011 BYTHE NATIONAL FRAME BUILDING ASSOCIATION