301 Erection Sequencing, Risk, and Hold Points

This 301 guide extends 201 Panel Lift, Set, and Brace Workflow with risk-controlled sequencing logic, hold points, and release gates.

1. Scope

Define how sequencing decisions are validated against stability, crane access, and temporary works constraints. OSHA 29 CFR 1926.703(d) requires the erection procedure to be prepared by a registered professional engineer; any field deviation from the approved sequence requires PE re-approval before lifting resumes. For federal projects, UFGS 03 47 13 §3.5 adds submittal and hold-point inspection obligations.

2. Core Risk Domains

  • Sequence-dependent instability

  • Crane radius growth and lane conflicts

  • Corner brace interference

  • Weather-driven partial completion risk

  • Rework risk after sequence changes

3. Hold-Point Framework

Define hold points at minimum for (basis: ACI 551.1R §7; TCA Recommended Practices):

  1. Pre-lift readiness

  2. Pick completion and rotation control

  3. Set on bearing and initial brace attach

  4. Plumb acceptance and crane release

  5. End-of-shift temporary stability (ACI 551.1R §7 and TCA Recommended Practices: all panels must be fully braced and stable at end of each work shift before personnel depart)

4. Sequence Change Control

When field conditions force resequencing:

  1. Record reason and affected panels.

  2. Re-check crane radius and access map.

  3. Re-check brace interference and anchor readiness.

  4. Re-approve hold points before resume. Material sequence deviations require PE re-review under OSHA 29 CFR 1926.703(d) before lifting resumes.

5. Forming, Layout, and Pick-Sequence Controls

Erection risk is strongly influenced by how panels are formed and arranged on casting beds. Include the following controls in sequence engineering:

  • Casting-bed layout map with panel orientation and planned pick order

  • Pick insert coordinates verified against formwork and reveal geometry before pour

  • Brace insert and pocket details verified for panels planned for exterior bracing

  • Lane preservation plan so early panel picks do not block later crane travel/stations

  • Conflict review for adjacent panels whose brace lanes or rigging swing paths overlap

If formwork changes modify pick orientation, panel rotation path, or crane access, sequence approval must be reopened and hold points reset.

6. Risk Register Template

For each risk item capture:

  • Trigger condition

  • Consequence

  • Detection method

  • Mitigation action

  • Responsible role

  • Hold-point linkage

7. Daily Engineering/Field Sync

Minimum daily review:

  • Planned panel set list vs actual

  • Open engineering exceptions

  • Weather and wind windows

  • Unreleased hold points

8. Standards References

  • OSHA 29 CFR 1926.703(d) — Tilt-up erection procedure must be prepared by a registered professional engineer; field deviation requires PE re-approval

  • ACI 551.1R §7 — Temporary stability requirements, minimum hold-point structure, and brace adequacy during erection

  • TCA Recommended Practices — Field sequencing guidance, corner condition procedures, and daily stability check criteria

  • UFGS 03 47 13 §3.5 — Federal project requirements: erection sequencing submittals, hold-point inspection obligations, and Contracting Officer Representative notification

  • OSHA 29 CFR 1926.752 — Site layout and construction sequence requirements relevant to structural erection safety

9. TODO Project Fill-In

  • Add project hold-point checklist

  • Add escalation tree and response times

  • Add sequence rollback playbook