CHECKLISTS FOR THE QUALITY ASSURANCE OF CALCULATIONS, DESIGN AND DRAWING PRODUCTION
Please feel free to add to it, modify it, and even delete items as you see fit. Its use is optimized when personalized with your individual experiences and tailored to your projects.
This checklist is not intended to be used in an absolute or exact science manner, but rather as an efficient production tool which will likely produce better and safer designs and drawings, than if the checklist had not been used.
The checklist is not intended to be a "how-to" design manual or even a procedural manual, but rather a list of reminders to help verify that all critical calculation and design considerations have been made and that adequate and essential detail information has been provided.
Quality Assurance
It is very easy for a designer to get absorbed in state of the art calculations and design methodologies and then neglect attention to some of the relatively mundane details. These details, although sometimes tedious, are nonetheless essential for a complete and safe structure.
The use off a checklist can help the engineer remember to include or check all of the numerous items which are essential for a complete structural design.
DPIC, liability insurer of engineers, recommends developing and using checklists as a means towards a more aggressive approach to error detection. DPIC states that "Obviously, technical mistakes cause embarrassment and cost time and money. But, more importantly, they can cost lives. The true professional regards checking aids and other sources of information enthusiastically - not resentfully - recognizing that anything that produces a better final product has value."
ICBO has produced a document known as the 1994 UBC Structural Checklist. This is a 96-page document intended for engineers and plan reviewers. It basically itemizes and discusses or rewords every structural element in the code. The document is worth reviewing, especially as a learning tool. It is however a bit lengthy to use consistently on each project and, of course, it only covers Code items.
The checklist herein covers calculations, analysis, Code, design and drawing production issues. The checklist is composed of a series of keywords and phrases intended to "jog your memory" about items to be included in the design and drawing production. It is intended to be used by experienced professionals, consistently and expeditiously on each project. A review of the checklist should take less than one hour.
The experienced engineer may be likened to a licensed airplane pilot who knows and understands all the procedures to fly a plane. The pilot, nonetheless, uses a checklist prior to throttling up the runway for take-off.
Use of Checklist
The checklist consists of two main parts:
+ Calculations, Analysis and Code
+ Design and Drawing Production
The first section uses the Uniform Building Code (UBC) as a point of departure. Typical drawing sequence and materials format the second section.
It is intended that designers, checkers or principals for quality review near the end of a project will use this checklist. Internal office review practices may vary from firm to firm. Some firms perform a quality review at approximately the 30% complete stage, in order to "ratify" the choice of structural system, materials, and force criteria. Parts of the checklist may be used at that stage, prior to proceeding with final analysis and member design.
We routinely keeps a "Follow-up" list during a project. Notations are made for items that will be followed up on later. This allows the engineer to continue his current task, but without forgetting to return to a recent thought. Examples of notations made to a follow-up list include the following:
+ Add laminated wood beams to specifications
+ Get dimension of block wall from architect and show on sheet S2
+ Detail embed plate for bridging connection
+ Show CMU wall joint spacing on plan sheet S1
+ Reference soils report in general notes
+ Show contraction joints in slab on grade
+ Etc.
The follow-up list is generally reviewed in conjunction with this checklist.
While this checklist does not cover everything possible it is believed that calculations and drawings will nonetheless be improved by using the checklist versus not having used the checklist.
References
ICBO, 1994, Uniform Building Code, Structural Engineering Provisions, International Conference of Building Officials, Whittier California
ICBO, 1997, Uniform Building Code, Structural Engineering Provisions, International Conference of Building Officials, Whittier California
ICBO, 1994, 1994 UBC Structural CheckList, International Conference of Building Officials, Whittier California
DPIC, 1988, Lessons In Professional Liability, Design Professionals Insurance Company, Monterey, California
CHECKLISTS FOR THE QUALITY ASSURANCE OF CALCULATIONS, DESIGN AND DRAWING PRODUCTION
CALCULATIONS, ANALYSIS, AND CODE
Verify the that the following items have been addressed and are included in the calculations and Code checks:
Gravity Loading
1. Review and compare initial dead load assumptions with the weights of the members chosen for final design
2. Are Dead Loads overly conservative, i.e. very heavy such that wind uplift and lateral overturning are not safe, use .85 dead load or less to resist overturning
1. Units consistent, ft, in, kips, degrees vs radians
2. Member orientation correct? Weak vs strong axis bending.
3. Global vs local loading direction
4. Positive y loading is up or down, self weight loading is down
5. Check plot of model for configuration, load and reaction direction, case by case
6. AISC unbraced lengths may be greater than the default length of node to node; k, Cm, Cb defaults, x, y directions
7. Global Restraints: Are global restraints appropriate? If a large horizontal reaction is output, then the foundation must be designed for that force.
8. Are mid span moments, forces, deflections reported and critical? Or reports at nodes only?
9. Connection design based on load path vs reported member end force: e.g. For a concentric braced frame with an in-plane offset, the connection of beam to column may need to be designed for the reported end force plus the horizontal component of the brace.
10. Thermal expansion and contraction stresses (building greater than 200' in plan)
Foundations (UBC 94 pg 2-48) [UBC 97 pg 2-43]
1. Allowable bearing pressures, net? Working stress?
6. Check overturning stability, sliding, bearing pressure, concrete bending/shear in wall and footing, assure adequate development length in footing rebar.
Concrete
1. Include Load Factors, 1.4 DL, 1.7 LL
2. Include phi factors on materials
3. Flexure ballpark check:
4. As req'd (in^2) = Mu (ft-k) / [4*d (in)]
5. Spread footings: check bending, one way shear, punching shear
6. Stirrups for torsion
7. Shear friction calcs: ld on each side of plane (ACI 11.7.8) similar at construction joints
8. Lightweight concrete: Reduction factor, lambda, for shear, ld
9. Splices: factors affecting splice length: f'c, Fy, spacing,cover, col/beam/wall/ductile, top bar, lightweight conc, epoxy coated, excess reinforcing, class A or B, zone 3& 4
4. 135 degree stirrups and ties @ 4" oc, ductile detailing
Anchor Bolts and Headed Studs
1. Reduce capacity for close spacing, edge distance. Use conservative UBC 94 Table 19-E pg 2-267, double tensile values if special inspection, or calculate pullout cones as per pg 2-254.
2. [UBC 97 pg 2-181, 2-168]
Expansion Anchors
1. Reduce capacity for close spacing, edge distance
Concrete Block Masonry (CMU)
1. No special inspection if 1/2 stresses are used in design, E does not get divided by 2. (UBC 94 pg 2-310)
2. [UBC 97 pg 2-209]
3. Check bond length of flexural reinforcement
4. Minimum 200 plf anchorage of walls to roof
5. (UBC 94 pg 2-6) [280 plf UBC 97 pg 2-3]
6. Deflection for lintel or veneer support < L/600 (UBC 94 pg 2-317) [UBC 97 pg 2-2133]
CMU Seismic
1. Working Stress Design (UBC 94 pg 2-320)
2. [UBC 97 pg 2-214]
3. 1.5 factor for seismic loads in shearwalls, working stress
4. (UBC 94 pg 2-321) [UBC 97 pg 2-215]
Steel
1. Verify material grade used i.e. Gr 50 for shapes, but also for plates and small angles?
Steel Beams
1. Brace compression flange: bottom flange for continuous beams, net wind uplift, design brace for 2% + of flange force
2. Beam stiffeners required atop steel columns for stability
3. Torsion accounted for?
Steel Columns
1. K > 1.0 if moment frame, i.e. column not braced with shearwall or X braced frame.
2. Moment due to eccentricity of beam end connection used
9. Special Moment Frame requirements SMRF (UBC 94 pg 2-360) [UBC 97 pg 2-256]
10. Connections, seismic provisions, follow Code
Steel Seismic Braced Frames
1. (UBC 94 pg 2-363) [UBC 97 pg 2-257]
Concentric Braced Frames (CBF)
1. (UBC 94 pg 2-364) [UBC 97 pg 2-257]
2. Slenderness minimums
3. Fas = B Fa for brace member
4. Max 70 % of braces oriented in same direction
5. Built-up members, stitch plates, local 1/r
6. Width thickness minimums
7. Chevron bracing requirements, 1.5 factor (UBC 94 2211.8.4.1 pg 2-365) apply to diagonal brace member only and not to beams, columns or brace connection [UBC 97 pg 2-258]
8. No K bracing, no non-concentric bracing
9. One and two Story buildings, OK to design for 3 Rw/8
10. [Omega zero] forces with relaxed requirements
11. Non-building Structures: Rw from Nonbuilding table (UBC 94 pg 2-39) [UBC 97 pg 2-34], need only comply with connection requirements for braced frames (UBC 94 pg 2-365) [UBC 97 pg 2-258]
3. Bolt sizes, quantity, type (A325N, A325SC, A307), scheduled per beam depth or location
4. Hole types: STD, OVS, short or long slots and orientation of slot
5. Snug tight, fully pretensioned or slip critical; inspection
6. Faying surfaces for SC bolts, no paint
7. Erection sequence, plausibility (shop weld, field bolt)
8. Special detail for W6 and C6 connections w/ 2 bolts
9. Allowance for k fillet, coping, wrench clearance
10. Web stiffeners req'd for steel beams continuous over tops of columns for stability.
11. Web stiffeners req'd for handrail posts at steel beams?
12. If fabricator is to design any connections, then provide performance specification, define which members, provide all loads, define scope and responsibility, require fabricator's seal.
Steel Baseplates
1. Plan dimensions, thickness
2. Anchor bolts; length, embedment, projection, threads, min edge distance, minimum of 4 bolts for erection safety
7. Weld to column (avoid fillet welds in tension for high seismic loads in critical locations)
8. Grout: "non-shrink", thickness, relief holes for large baseplates
9. Bracing work points defined
Open Web Steel Joists
1. Joist bearing elevation
2. 2 1/2" bearing depth compatible with adjacent and parallel steel beam connections
3. Performance specification, design responsibility, seal by fabricator
4. Bridging design by fabricator, connection to building by designer, detail connection
5. Define loads for design, including dead load to be used, equipment, roof screens, snow (Pg vs Pf), snow drift, rain on snow surcharge, live load reduction
6. Define collector loading
7. Specify deflection criteria, vibration
8. Paint (primer/none)
9. 2 1/2" tall hat or tube steel between joist bearings for shear transfer (between metal deck and collector beam), weld size and spacing
10. Bolted connections required at top of column locations
2. Partitions: Top of wall: lateral bracing and vertical slotted connection
3. At sloping roofs, do horizontal or large members protrude through ceiling or roof.
4. Parapets secure for wind, window washers
5. Heavy items connected to structure?
6. Brick veneer ties
Cladding and Windows
1. Performance specification, design responsibility, seal by fabricator
2. Diagonal brace to top of windows
Constructability
1. Can it be built without skyhooks?
2. Sequence of construction
3. Rebar congestion
4. Bolt tightening access
5. Likely locations of construction joints
Drawing Production Epilogue
1. Review "follow-up list"
2. Has information been called out in more than one location on the drawings? If so, is it consistent and/or is it necessary to show the item in more than one location.
3. Are all section callouts cut or noted from plans?
4. Do Specifications match drawing notes?
Final Review and Plotting
1. Issue date (updated)
2. Stamped "PRELIMINARY, NOT FOR CONSTRUCTION, FOR BID", etc.