Detailing of steel structures is a very critical process which requires high concentration and understanding. It is not a one day work. The other process of fabrication and erection depends on the detailed sheets completely and that is why any mistake can result into re-fabrication of component which is generally costly in nature because Steel costs thousands more per tonne.
After the designing part is done a model is created with the help of softwares. In detailing each and every element is detailed with its height, width, shape, exact cutting length, cross section, connecting bolts diameter, welding and weldment assembly.
Such a drawing is called a shop drawing, or a fabrication drawing, or manufacturing drawing.
In the past these drawings were prepared by expert draftsman that use to consume a lot of time but now modeling softwares produces these drawings.
If we talk about modeling softwares one of which is autodesk’s advance steel which comes with variety of drawing style applicable to any model thus saving time.
These involves two main types of drawings-
- Shop drawing
- Erection drawing
In shop drawings or detail drawings every minute detail of individual element or component (column, beam, braces, type and size of bolts, type and size of welding, etc) that needs to be made by the steel fabricator is mentioned.
These include material specification, size, cross section, dimension, and number of times they are present. Also a complete bill of materials is there which gives an idea about how much cost would be incurred.
Erection drawings as the name suggest are helps in placing the elements in their correct position. These covers ground level heights, dimensions and position of each component, their connection details like bolt assembly, welding spots.
The production of fabricated steel starts with the steel detailing group, which follows an established procedure to ensure an orderly flow of work through the shop. A tremendous amount of paperwork is involved. Drawings and bills (standard forms) prepared by the steel detailer form an important part of this paperwork.
A steel detailer plays a tremendous role in the overall project progress. The detailer must be familiar with regulations and guidelines from all aspects of construction. OSHA, AISC, minimum bearing limits, and common standards/practices must be included in the detailer’s skill set. A good detailer can make even the most complex project very feasible for any fabricator.
The drawing layouts prepared by the detailer must be understandable as it is not only seen by fabricators but are helpful for HVAC, plumbing installation perspective.
Structural steel detailing process acts as a medium between the designer, architect and fabricator, any discrepancies in the drawing observed by the fabricator can directly or indirectly get resolved by bringing to the attention of the design team.
A typical detailing group would perform its procedures in approximately the following sequence:
- Initiate job and fabricator setup (i.e., pre-planned checklists).
- Prepare typical details, job standard sheets, layouts, and calculation sheets.
- Prepare system of assembling and shipping piece marks.
- Prepare and check advance bills for ordering material.
- Make and check anchor rod/embedment drawings.
- Make and check erection drawings.
- Make and check detail shop drawings, including bills of material.
- Secure approval of shop drawings.
- Incorporate approval comments.
- Issue shop drawings to the shop.
- Prepare lists of field fasteners.
- Fit check.
- Issue shop and erection drawings to field.
The Detailing Process
Receive contract plans and specification.
Send to approval.
Make & Check detail drawings and shop bills.
Prepare list of fasteners
Receive from approval and issue to shop field.
Send details & erection plans for approval.
Make & check erection plans.
Prepare system for assembling and shipping piece marks, typical details, job standards sheets, layouts & calculated sheets.
Make and check anchor rod/embedment plans and details.
Prepare and check advance bills.
Send to purchasing.
Receive from approval & issue to shop and field.