cliff schwinger
TRANSCRIPT
Quality Assurance For Structural Quality Assurance For Structural
Engineering FirmsEngineering Firms
Tips, Techniques & StrategiesTips, Techniques & Strategies
by by
Clifford Schwinger, P.E.
What we’ll be covering…
• Quality Assurance Programs
What we’ll be covering…
• Quality Assurance Programs
• Quality Assurance Review procedures,
tips and techniques.tips and techniques.
The Quality Assurance ProgramThe Quality Assurance Program
Defined set of procedures and standards
used to facilitate design and to facilitate
documentation of that design.
Advantages:Advantages:
• Better design
• Better drawings
• More efficient design process • More efficient design process
• Fewer mistakes
• Fewer RFI’s / change orders• Fewer RFI’s / change orders
• Increased profits
Why is a QA program important?
• Fast schedules
• More changes
Why is a QA program important?
• More changes
• Less experienced engineers detailing/coordinating
• Computers disconnecting some from reality• Computers disconnecting some from reality
• Complex Codes
• RFI’s and change orders
• Lost art of structural drafting
• The need for good communication
In the past…
A single QA review was performed after
the design was completed and before the
In the past…
the design was completed and before the
drawings went out the door…
Because of fast-track scheduling this no Because of fast-track scheduling this no
longer works.
Today…
Projects require a series of QA
reviews conducted prior to issuance
of each structural package.of each structural package.
The better the QA program, the easier The better the QA program, the easier
the task of performing QA reviews.the task of performing QA reviews.
The Quality Assurance Program
The QA program
Components:
The QA program
Components:
• Training for young engineers
• Design standards• Design standards
• Drawing and CAD standards
• Project Delivery System• Project Delivery System
• Knowledge Base
• QA reviews and ongoing QA manager • QA reviews and ongoing QA manager
involvement in project
The QA programThe QA program
1. Training for young engineers:
Weekly formal training seminars on topics
1. Training for young engineers:
Weekly formal training seminars on topics
required to provide young engineers the
skills and knowledge needed to become
more productive.more productive.
The QA programThe QA program
2. Design standards:
In-house design guides, office
standards and checklists for all topics
2. Design standards:
standards and checklists for all topics
related to structural design.
The QA programThe QA program
3. Drafting and CAD standards:
• Standardized drafting procedures
3. Drafting and CAD standards:
• Layers
• Typical details
• “go-by” drawings
• Standard blocks
The QA programThe QA program
4. Project Delivery System
Checklists and procedures:
• Project startup
4. Project Delivery System
• Project startup
• Schematic design
• Design development• Design development
• Contract documents
• Construction Administration
The QA programThe QA program
5. Knowledge Base
• Server-based database of all
knowledge related to structural
5. Knowledge Base
knowledge related to structural
engineering.
• Similar to Wikipedia• Similar to Wikipedia
The QA programThe QA program
6. Involvement of QA manager:
• QA manager familiar with projects during design.
6. Involvement of QA manager:
• Signoff by QA manager on details and framing
prior to going to CAD (ongoing QA).
• Formal QA reviews at defined milestones • Formal QA reviews at defined milestones
The Quality Assurance
ReviewReview
Strategies & tactics
Quality Assurance Reviews
In-house reviews conducted to verify that
Quality Assurance Reviews
In-house reviews conducted to verify that
design and documentation is in conformance
with procedures, practices and standards with procedures, practices and standards
mandated by the QA program.
Primary purposes of the QA review: Primary purposes of the QA review:
• Redundancy• Redundancy
• Monitor effectiveness of QA program.
QA reviews
Typical QA review schedule:
QA reviews
Typical QA review schedule:
Pile bid
Steel mill orderSteel mill order
Foundation concrete
Steel detailing
100% structural steel
100% concrete
“Issued For Construction”“Issued For Construction”
QA reviews
Primary Strategy
QA reviews
Primary Strategy
Look at:
• The big picture (load paths)• The big picture (load paths)
• Critical connection details• Critical connection details
QA reviews
Secondary strategy:
QA reviews
Look at the drawings through the eyes of a:
• Contractor
• Detailer• Detailer
• Inspector
• Engineer performing a peer review or • Engineer performing a peer review or
value engineering review.
• Building official• Building official
• Young engineer reviewing shop drawings
• Lawyer• Lawyer
QA reviews
QA review tactics:• Verify load paths
QA reviews
• Verify load paths
• Check framing
• Check special connections• Check special connections
• Look for mistakes
• Look for the subtleties
• Look at the drawings through contractor’s eyes. • Look at the drawings through contractor’s eyes.
• Review for clarity/consistency
• Look for omissions
• Look for “little” little things • Look for “little” little things
• Look for “big” little things
• Structural dwgs. match Arch. dwgs.?• Structural dwgs. match Arch. dwgs.?
QA reviews
1. Load path issues:
•Any unrealistic load paths?
QA reviews
•Any unrealistic load paths?
•Loads jumping in/out of shear walls / braced frames?
•Any unrealistic “rigid” diaphragms?•Any unrealistic “rigid” diaphragms?
•Any loads on the structure not in the computer model?
QA reviews
Example: Unrealistic distribution of lateral
QA reviews
Example: Unrealistic distribution of lateral
loads between lateral load resisting elements.
QA reviews
Example: Braced
QA reviews
Example: Braced
frame forces not
making sense (due to
rigid diaphragm
assumption in
computer model).computer model).
QA reviews
2. Check framing (gravity and lateral):
QA reviews
Check:
• Typical framing to verify model• Typical framing to verify model• Major load carrying members• Wind and seismic loads• Wind and seismic loads• Unique framing not in computer model
QA reviews
Items requiring special attention:
Elevators
Escalators
Folding partitions
Special hang pointsEscalators
Facades
Davits
Special hang points
Rooftop MEP loads
Heavy hung piping
Stairs
Monumental stairs
Hangers
Special loads on joists
Horizontal loads from
riggingHangers
Theater rigging
rigging
Catwalks
Expansion jointsExpansion joints
QA reviews
3. Check connections:
QA reviews
• Critical connections
• Unusual connections• Unusual connections
• Connections w/ complex geometry
• Connections w/ large reactions
QA reviews
4. Look for mistakes:
QA reviews
• Wrong reactions
• Members too small
• Improper framing configurations• Improper framing configurations
• Not enough reinforcing steel
• Punching shear problems• Punching shear problems
• Missing structural integrity reinforcing steel
• Missing sections and details
• Mistakes in sections and details• Mistakes in sections and details
QA reviews
Carelessness can result
in objects obscuring
QA reviews
in objects obscuring
important text. Errors like
these can cause these can cause
structural failures.
QA reviews
Slab opening added near column; girder shifted to
avoid opening; girder now connecting to beam but
QA reviews
avoid opening; girder now connecting to beam but
beam and beam reaction not revised.
QA reviews
Spandrels at openings are unbraced and take lateral
wind loads. Design accordingly. Facade braces and
QA reviews
wind loads. Design accordingly. Facade braces and
kickers can’t be used to brace facade at stair
openings.openings.
QA reviews
5. Look for subtleties:
QA reviews
• Column splices at inappropriate locations (mid-
height of 80’ unbraced height).
• Columns mistakenly assumed to be braced by • Columns mistakenly assumed to be braced by
mezzanines.
• Floors diaphragms w/ insufficient strength/stiffness • Floors diaphragms w/ insufficient strength/stiffness
to brace columns (see next slide)
QA reviews
Floor diaphragms need sufficient
QA reviews
Floor diaphragms need sufficient
strength & stiffness to brace columns.
QA reviews
6. Look at drawings through the eyes of a contractor:
QA reviews
• Everything shown that will allow contractor to build
structure without having to guess or issue RFI’s?
• Every linear foot of building perimeter covered by a • Every linear foot of building perimeter covered by a
section?
• Everything clearly indicated?• Everything clearly indicated?
• Can drawings be interpreted by someone who’s not an
engineer?
QA reviews
7. Review for clarity & consistency:
QA reviews
• Look for conflicts between framing plans and
sections/details.
• Inconsistencies with framing• Inconsistencies with framingGroup similar beams
Consistency = simplicity = economy
• Drafting inconsistencies• Drafting inconsistencies
QA reviews
8. Look for omissions:
QA reviews
• Missing things often hardest to find
• Missing:• Missing:
Reactions
Section and details
Dimensions and elevationsDimensions and elevations
Sizes
Reinforcing steel
QA reviews
9. Look for “little” little things:
QA reviews
spelling mistakes!
“FABRICATOR MAY PROPSE ALTERNITIVE MOMENT
CONNECTIONS THAT MATCH MOMENT AND SHEAR
WALUES LISTED IN SCHUDULE.”
QA reviews
10. Look for BIG little things:
QA reviews
Some “small” drafting errors can cause structural failures.
QA reviews
11. Do structural dwgs. match architectural dwgs.?
QA reviews
11. Do structural dwgs. match architectural dwgs.?
• Slab edges• Slab edges
• Columns
• Slab openings (see next slide)• Slab openings (see next slide)
QA reviewsQA reviews
Slab opening
cutting off load path
to edge column; to edge column;
opening not shown
on structural on structural
drawings!
New challenges:
• Architectural and MEP changes after structural
design is completed and QA reviews
performed.performed.
• Changes during construction that slip through
the cracks of the QA process.the cracks of the QA process.
• BIM
Summary
Six elements of a QA program
Summary
Six elements of a QA program
• PDS
• Design standards
• Drawing standards
• Knowledge base
• Training for engineers• Training for engineers
• Multiple and ongoing QA reviews during design
QA reviews serve two purposes
• Redundancy• Redundancy
• Monitor effectiveness of QA program.
QA is a continual processQA is a continual process
Thank you!
QUESTIONS?