Spot checking shop drawings
The Project Manager
Missing running dimensions
Missing weld details
Missing hole locations
Missing cope sizes and radius
Missing N/S/E/W indicators
Too much information in too small of a space in details
Too many parts on a sheet
Detail cuts showing reversed details
Improper use of Right and Left hand details
Dimensioning from the right hand end of the beam
Dimensioning from the underside of beam up
Detail cuts looking up and looking left
Lack of consistency with detail cuts
Drain and vent holes for galvanized items as required
The use of “ditto” marks
Drawing errors to watch for:
Symptoms of problems within the shop detail drawings generally do not show up until the materials are being purchased or when fabrication has begun. Early indicators will be frequent visits to the office by the shop foreman to discuss questions on the shop drawings with the project manager.
Most steel fabricators assume that the detail drawings they have purchased will be correct, so not much time is spent checking to be sure that the drawings will be usable by the shop.
The right time for the steel fabricator to review the shop drawings is prior to submitting the drawings for the approval process. Once the drawings are submitted for approval they become documents of record by three different parties consisting of the General Contractor, the Architect and the Engineer. Corrections to drawings after approval may prove costly and is frowned upon by the contractor and the design team.
The financial impacts for the fabricator begin when the worker stops what they are doing and goes to the shop foreman, who then goes into the office and to discuss the issues with the drawings that they have found. The project manager will then contact the steel detailer for answers if they are unable to resolve it for themselves. Now you have three people involved in sorting out drawing issues before it gets to the one that created the drawings.
It is common that assumptions are made by the shop managers and the work continues, only then to have issues corrected in the field, or shop re-fabrication. This is called crisis management, and is a driving force to propelling projects over budget in shop labor hours.
The project manager can take the time to look for the most obvious things like uncompleted information in the title block. The steel detailer should have filled in all of the standard information with regard to standard hole sizes, bolt types including diameter and length, grade of materials being used, the weld process, QC level, and coating information. Look for references back to the erection drawing the parts will belong to. Another common mistake to watch for is the material list not matching with the picture of the parts showing material size and lengths.
You would think that with all the new modeling programs being used that these errors would not show up on the drawings. The information on the shop drawings has to be edited in by the detailer, so they still have to know what to show and how to show it. Not doing this step correctly could show the information wrong for the shop.
Are you running the job, or is the job running you?
Steel Advice - June 2011