Erection Aids
Erection aids are temporary structural features designed into the fabrication to assist in setting, aligning, and holding members in position during erection. Common erection aids include: clip tabs welded to columns to support beam ends before bolts are installed; erection pins at base plate anchor bolt patterns that allow single-bolt temporary alignment; spandrel erection lugs that allow crane rigging to be released while the next pick is made. Detailers should routinely add erection aids when the connection geometry makes temporary support necessary — not wait for the ironworkers to ask.
Connection Sequencing
The order in which field connections are made determines how efficiently erection proceeds. On moment-frame structures, specifying that bolted flange connections be snug-tightened first allows the frame to be plumbed before final tightening — rather than requiring perfect plumb at each piece before proceeding. Including erection sequence notes on the drawing (or in a separate erection note sheet) gives the superintendent a starting point for planning the pick sequence before the crane is on site.
Bolt Accessibility and Wrench Clearances
A bolt that is geometrically present in the model but physically inaccessible to a wrench is a field problem. AISC recommends minimum wrench clearances of 1" around the nut and bolt head for standard impact wrenches. The 3D model allows detailers to check these clearances visually and virtually — something 2D drafting cannot do. Detailers who routinely check bolt access in the model before issuing drawings save erection crews the frustration of discovering inaccessible fasteners after the member is set.
Crane Pick Optimization Through Member Segmentation
Long and heavy members create crane pick challenges — particularly on constrained sites or in projects where the crane is smaller than ideal. Detailers who understand the erection contractor's crane capacity can segment assemblies at appropriate points to keep each pick within the crane's rated capacity. Column splices, for example, can be located to optimize the length-to-weight ratio per pick rather than defaulting to an arbitrary elevation. Providing the detailer with the erection contractor's crane spec at project start allows these optimizations to be made in the model before fabrication — not after the first pick fails.
Member Orientation and Labeling for Field Efficiency
Members that look similar from multiple angles — wide-flange sections with similar flange widths, HSS in square profiles — require clear orientation marks to prevent field installation errors. On asymmetric connections, indicating the 'top' or 'north' face on the erection drawing prevents a member from being erected in the wrong orientation. Stenciled erection marks ('TOP' on the top flange, 'N' on the north face) take two minutes to add in the shop and save the ironworker crew the cost of lowering and re-rigging a piece that was set in the wrong orientation. The detailer should coordinate orientation marking requirements with the fabricator's marking standards.
Field Weld vs. Field Bolt Decisions and Their Erection Impact
The choice between field welding and field bolting is partly an engineering decision and partly an erection productivity decision. Field-bolted connections are faster to erect — the ironworker installs bolts directly without requiring a welding crew, welding equipment, wind protection, and preheat. Field-welded connections require certified welders, electrode management per AWS D1.1, potential preheat for thick plates, and wind protection at the joint. On projects where the erection schedule is tight and the structural design permits bolted field connections, recommending bolted alternatives to field welds — subject to EOR approval — can meaningfully compress the erection schedule.
Coordination with the Ironworker Superintendent Before Detailing
The most underutilized erectability improvement tool is a pre-detailing conversation with the ironworker superintendent or erection contractor. A 30-minute discussion about their planned erection sequence, crane location and coverage radius, maximum pick weights, and typical connection preferences can influence dozens of detailing decisions that collectively make a structure significantly faster to erect. Detailers who include erection contractors in the kickoff process produce drawings that the field crew can execute efficiently — not drawings that the field crew has to work around.
- Planned crane location and maximum reach radius
- Target maximum pick weight and preferred assembly sizes
- Preferred field connection types — bolted vs. welded preferences
- Erection sequence priorities — which bays or floors first
- Known site access constraints that affect delivery and crane placement