Interior Design Consulting Agreement - PowerPoint by neg11394

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									  Needham & Associates
   Consulting Engineers

Fort Wayne, IN - Overland Park, KS

       http://www.needhamassoc.com
Serviceability Design of
    Metal Buildings
• Or….Why is my customer so
       unhappy???
• What does a contractor need to
            know???
          Your Speakers
       • Jeff Needham, Principal
– P.E., S.E in 20 states, started firm in 1989 in
                    Fort Wayne
   – BS and MS from University of Kansas

        • Andy Carter, Principal
  – P.E., S.E in 25 states, started in PEMB in
                       1968
   – BS Virginia Military Institute, MS from
                 Georgia Tech
What Does Needham and
    Associates Do?

 • General Practice Structural/Civil
             Engineers
 • Consultants to PEMB Industry
– Heavy Structures ( ex: large clear-spans,
       steel mills, special structures)
– Hardwall Buildings ( ex: site-cast, tilt-up
                 concrete)
Introduction

• Why consider serviceability(source of
  many problems and claims)
• Owner input (must have active input,
  common problem)
• Specific to structure’s use
• Easy to build in, difficult to repair
Example of Breakdown in
Serviceability Considerations

• Probably lack of communication between
  owner and contractor
• Project in Terra Haute, IN
Flammable Vapor Build-up in
Insulation
Types of Serviceability Issues

• Deflections and Drift (primary focus of this
  talk)
• Expansion/Contraction
• Camber
• Vibration
• Corrosion
• Connection Slip
Responsibility for Determining
Serviceability Requirements

• Generally not code issue
• Building manufacturer’s consideration only if
  informed by dealer
• Entity (Architect or Owner) specifying the
  building parameters specifies criteria
• Serviceability criteria need owner agreement
  of requirements & cost
Basic Deflection and Drift Ratios
Wall Considerations - Drift

• Metal walls usually have no real limit
• Masonry/tilt-up/precast wall vs. frame drift
• Base condition free to rotate - H/100
• Base condition fixed to rotate - H/200
• Do not use unreinforced masonry walls with
  PEMB
Typical NEW PEMB Hardwall
Buildings

• Designed for strict serviceability issues
• Load bearing walls
Wall Considerations - Deflection

 • Wainscot walls & framing above
 • Total deflection
   – sum of frame drift & girt deflection

 • Spandrel Beam (single girt) L/240, but not
   more than 1.5 inches
 • Details to enhance compatibility of
   materials, allow for movements
Special Considerations for
Bridge Cranes

• Complex topic
• Common drift limit H(eave ht)/200 under
  crane lateral load
• Crane beam deflection L(bay)/600 for vertical
  deflection
• Crane beam deflection L(bay)/400 for
  horizontal deflection
Typical Crane Installation

• Serviceability often controls design as
  opposed to strength
• Steel and weldment fatigue is a major
  serviceability issue
• Therefore, serviceability dictates cost
Crane Serviceability Controls
References for Bridge Cranes

• CMAA Standard 74 (Single Girder TR and UH
  Cranes)
• CMAA Standard 70 (Double Girder TR Cranes )
• Call (704) 552-8644 to order
• About $40 each
CMAA Standards 70 and 74
Interior Partitions & Ceiling
Considerations

• Suspended ceilings will telegraph roof
  deflections
Sprinkler Heads Indicate
Deflection

• Common winter callback
• May or may not indicate a real problem
Interior Partitions & Ceiling
Considerations

• Suspended ceilings will telegraph roof
  deflections
• Noticeable
  – in large open offices
  – junctions of ceilings & interior walls
Typical Ceiling Problem
Interior Partitions & Ceiling
Considerations

• Suspended ceilings will telegraph roof
  deflections
• Noticeable
   – in large open offices
   – junctions of ceilings & interior walls

• Don’t tie interior partitions to main framing
Good and Bad Details




      Bad          Good
  Interior Partitions & Ceiling
  Considerations
• Suspended ceilings will telegraph roof
  deflections
• Noticeable
   – in large open offices
   – junctions of ceilings & interior walls

• Don’t tie interior partitions to main framing
• Remember - Actual deflections are as much as
  25% higher than calculations indicate
Roof Considerations

• “L/Span” deflections
Comparison of L/Span
Deflections
• L/180 on typical Z-purlin
   – 20 foot bay = 1.33 inches, 30 foot bay = 2
     inches

• L/240 on typical roof bar joist
   – 30 foot bay = 1.5 inches less initial camber of
     3/8
   – Net deflection is 1.125, much less than Z-purlin

• Z-purlin deflection is magnified by “purlin
  roll”
Purlin Deflection
Roof Considerations

• “L/Span” deflections
• Purlin deflection at eaves and rakes
Eave Deflection/Ice Dam
Roof Considerations

• “L/Span” deflections
• Purlin deflection at eaves and rakes
• Ponding, with low slope roofs
Ponding

• Common failure type of joist roofs due to
  clogged drains, scuppers
• Can be caused by snow drifting
• Design checks for stability failure are usually
  not required for slopes of 1/4/12 or greater
• Stability checks may be required for slopes
  of 1/4/12 or greater if ice dams/snow drifts
  occur…Be Careful with this condition!
Ponding Problem on 1/2 to 12 Slope
Roof Considerations

• “L/Span” deflections
• Purlin deflection at eaves and rakes
• Ponding, with low slope roofs
• Panel distress & leakage caused by
  excessive purlin or frame deflections…this
  may be first “clue” of serviceability issue
Non-Deflection/Drift
Serviceability

           • Expansion/Contraction
 • Not usually an issue with all steel building
       • Watch for adjacent structure
   • Watch for collateral materials..tilt-up
             concrete especially
Non-Deflection/Drift
   Serviceability

       • Camber
      • Corrosion
       • Vibration
    • Connection Slip
Summary

• MBMA states that is up to owner (or his
  agent) to identify all materials so that the
  metal building can be designed to be
  compatible
• Know your owner/customer
• Don’t forget to “program” the job in the rush
  to start a design build job
• Require that manufacturer meet AISC “Steel
  Design Guide 3”
AISC “Steel Design Guide 3”

• Call AISC 800-644-2400
• Price $16
Questions????
Thank You!...Needham &
      Associates
  Consulting Engineers
233 W. Baker St.        8417 Santa Fe Dr.
Fort Wayne, IN 46802    Overland Park, KS 66212
(219)420-3400           (913)385-5300

        http://www.needhamassoc.com

								
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