Types of Priority Steel
Priority steel falls into several categories, each driven by a different constraint.
- Long-lead material — heavy wide-flange columns, HSS in non-standard sizes, or high-strength plate that requires extended mill lead times
- Anchor bolt packages — always first; requires foundation design to be confirmed before release
- Early erection zones — the first bay or building section to be erected, driven by site access or other trades working behind the steel
- Critical connections — moment frames, transfer beams, or cantilevered structures where connection design must be resolved before other work can proceed
- Mill order enablers — preliminary material lists on all members so orders can be placed even before connection details are final
How to Communicate Priorities to the Detailer
Provide a written priority matrix at kickoff: list each priority item, the reason it is priority, and the date by which it must be released. A priority matrix transforms vague urgency into actionable sequencing. Detailers who receive a matrix can build their modeling sequence around it; those who receive general statements like 'we need everything as fast as possible' cannot.
When Priorities Change Mid-Project
Site conditions, design changes, and subcontractor coordination frequently shift priority from one area to another. When priorities change, communicate the change to the detailing PM immediately and in writing. A priority change that is communicated two weeks in advance can be accommodated in the modeling sequence. A priority change communicated two days before a required release date requires emergency acceleration — which has a cost.
Long-Lead Material and Preliminary Mill Orders
Long-lead structural steel — heavy wide-flange shapes in W14 and W36 series above certain weights, HSS sections in non-standard wall thicknesses, and ASTM A913 or A992 grades in specialty sizes — can require 8–16 weeks from a domestic service center. Mill direct orders can exceed 20 weeks. To protect the fabrication schedule, these sections must be identified as priority items, and a preliminary material list covering these specific piece marks must be issued as early as possible — often before connection detailing is complete. The preliminary list provides section, approximate length, and grade; it is sufficient to commit a mill reservation even if exact cut lengths are not yet confirmed.
- W14×283 and heavier — often requires mill order, not service center stock
- W36 series heavy shapes — similar mill lead times; identify early
- HSS with wall thickness above 1/2" — limited stock; confirm availability at kickoff
- ASTM A913 grade 65 or 70 — specialty mill product, 12–16 week lead time
- Heavy plates (3" and above) — verify service center stock before assuming availability
Priority Sequencing for Multi-Phase Projects
On multi-phase or fast-track projects, priority sequencing becomes a formal document — a phased release matrix that assigns every member to a release package and every package to a planned release date. The matrix should be agreed between the fabricator, detailing PM, and erection superintendent before modeling begins. It gives the detailer a clear modeling sequence, gives the shop a production planning baseline, and gives the erection crew a delivery expectation. When priorities shift, the matrix is updated and re-issued — not renegotiated verbally with each change. Tectonix prepares a release matrix at kickoff on every project with phased erection requirements.
Communicating Priorities to the Detailer — A Practical Format
A priority matrix submitted at kickoff should include columns for: member type (column, beam, brace, misc), location (grid reference), the reason it is priority (long lead, early erection, crane access), the target release date, and any information prerequisites (foundation survey required, EOR confirmation of section pending). This format lets the detailer schedule modeling resources against real deadlines rather than treating all work as equally urgent. It also creates a written record of what was communicated, protecting both parties if a priority claim arises later.
Critical Connections and Transfer Members — High-Design-Risk Priorities
Beyond long-lead material and erection sequencing, a third category of priority steel is driven by engineering complexity: connections and members where the design is not yet resolved at detailing kickoff. Transfer beams carrying column loads above openings, cantilever structures, moment frames with seismic detailing requirements under AISC 341, and heavy plate girders in low-clearance conditions all require engineering resolution before detailing can proceed. If the EOR has not finalized these designs, detailing of the affected members must wait — but that wait must be surfaced as a documented hold, not absorbed silently. Identify these high-design-risk members in the kickoff meeting, confirm the EOR's timeline for finalizing the design, and enter them in the held-item log with a required response date. A transfer beam whose design arrives three weeks after kickoff is a three-week delay to that package — and if the package is on the critical path, a three-week delay to the fabrication start date.
- Transfer beams — identify at kickoff; confirm EOR design status before modeling begins
- Cantilevered structures — connection design is often complex; confirm delegated design responsibility
- AISC 341 SFRS elements — confirm seismic design category, R-factor, and pre-qualified connection type before detailing
- Heavy plate girders — require close coordination with fabricator on shop capability and section availability
- Long-span trusses — panel point geometry must be confirmed before any member can be finalized
Using Tekla Structures to Manage Priority Sequencing in the Model
Tekla Structures provides native attributes for managing release sequencing directly in the model. The Phase attribute can assign each member to a release package (Phase 1, Phase 2, etc.), allowing the detailer to filter the model by phase and extract drawings only for members in the current release. The Erection Sequence attribute supports ordering within a phase. Custom user-defined attributes (UDAs) can be added to flag long-lead members, held items, or members awaiting connection design confirmation — making the model itself the master tracking tool rather than a separate spreadsheet. When the detaling team and fabricator's PM are both working from the same Tekla model data — even via model sharing or IFC-based progress exports — priority tracking becomes transparent and real-time rather than dependent on weekly status calls.