201 Rigging Hardware and Geometry

This 201 guide expands the 101 overview in Lifting, Rigging, and Bracing with practical rigging setup and geometry control.

1. Purpose

Define the rigging system assumptions and geometry checks needed to move from conceptual picks to a coordinated lift plan.

2. Inputs

  • Panel geometry and center of gravity estimate

  • Pick insert marks and capacities

  • Insert edge distance and reinforcement context

  • Planned sling, shackle, and spreader configuration

3. Outputs

  • Rigging tree by panel type

  • Geometry envelope for sling angles and spreader use

  • Hardware compatibility matrix (insert, clutch, shackle, sling)

  • Exception list for asymmetrical or high-risk panels

4. Hardware Stack Definition

Document each element in the load path:

  • Hook block

  • Master link

  • Shackle/swivel (capacity and required marking per ASME B30.26)

  • Spreader/equalizer beam (if used; custom fabrication must comply with ASME BTH-1)

  • Sling set (rated capacity, angle derating, and inspection per ASME B30.9)

  • Insert clutch/connector (qualification per insert manufacturer; rated load marking required)

  • Cast-in insert (capacity from ACI 318 Ch. 17 breakout analysis and manufacturer load tables)

5. Geometry Control

For each pick family, define:

  • Sling angle range (ASME B30.9; minimum 60° from horizontal preferred; 45° permitted with capacity derating; angles below the manufacturer’s tabulated minimum are prohibited)

  • Headroom constraints

  • Spreader length constraints

  • Expected load share assumptions

6. Asymmetry and CG Shift

When openings or pilasters shift CG:

  1. Recompute pick-side load distribution (ACI 551.1R §6; re-establish CG and verify each leg does not exceed rated insert capacity).

  2. Verify each leg and connector demand.

  3. Adjust pick layout or spreader configuration.

  4. Re-issue panel-specific rigging note.

7. Standard Data Fields

Track per panel:

  • Pick ID and coordinates

  • Rigging profile ID

  • Nominal and amplified leg loads (ACI 551.1R §6; dynamic amplification factor typically 1.25–2.0; engineer-specified based on lift method and equipment)

  • Required concrete strength at lift (ACI 551.1R §6; minimum typically 3,000 psi; engineer-specified)

  • Strongback requirement flag

8. Pick-Point and Spreader Geometry Limits

8.1 Pick-Point Count Expectations

Use the 101 guidance as the screening baseline:

  • Typical minimum: 2 picks for standard panels

  • Typical range: 2 to 4 picks for most commercial panels

  • Large/irregular panels: 4 picks are common, with 6 used when required by engineered load distribution

There is no single codified maximum pick count. Final count is controlled by insert demand, panel CG, rigging geometry, and concrete strength at lift (ACI 551.1R §6 and insert manufacturer tables).

8.2 Sling and Spreader Geometry

  • Keep sling leg angles within ASME B30.9 and manufacturer limits

  • Treat 60 degrees from horizontal as preferred geometry for balanced leg loading

  • Allow 45 degrees from horizontal only with explicit capacity derating and documented check

  • Use spreader/equalizer beams when geometry would otherwise drive flat sling angles or undesirable compression in panel edges

No universal code prescribes one “maximum spreader length” or a single allowable “deflection angle” for all rigs. Those limits are device-specific and must come from engineered below-the-hook design (ASME BTH-1) and manufacturer data.

8.3 Two-Pick-to-One-Hook Connections

When two picks are resolved into a single crane hook connection, document the complete load path and controlling assumptions:

  • Master link and shackle rating compatibility (ASME B30.26)

  • Leg length equality assumptions or intentional unequal-leg design basis

  • Equalizer/spreader behavior used to control load share

  • No pulley/reeving substitutions unless an engineered rigging plan explicitly permits it

8.4 Multi-Point Picks (8 to 16 Point Panels)

For large, long, or opening-heavy panels, 8- to 16-point picks are common and should be documented as a rigging tree, not as a single “equal-leg” assumption.

Required controls:

  • Break the rigging into levels (hook, primary beam, secondary beam, drop lines, inserts)

  • Assign each insert to a tributary load group from the equalizer geometry

  • Verify each lower-level member for the local reaction it actually attracts

  • Check that no individual insert, clutch, shackle, sling, or beam connection exceeds rated capacity

For 8 to 16 picks, include an explicit statement in the erection package that load share is based on engineered vector statics plus compatibility assumptions, not simple equal division by pick count.

8.5 Angle Convention and Conversion (Horizontal vs Vertical)

Angle confusion causes major field errors. Use both references on every rigging sketch:

  • $\theta_h$: sling angle from horizontal

  • $\theta_v$: sling angle from vertical

These are related by:

$$ \theta_h + \theta_v = 90^\circ $$

So, a “90 degrees from horizontal” line is vertical and equals $0^\circ$ from vertical.

For a symmetric two-leg case, leg tension is:

$$ T = \frac{W}{2\sin(\theta_h)} = \frac{W}{2\cos(\theta_v)} $$

Where:

  • $T$ is tension in each leg

  • $W$ is supported load at that node

Useful check values (two-leg symmetric node):

  • $\theta_v = 0^\circ$ ($\theta_h = 90^\circ$): $T = 0.50W$

  • $\theta_v = 15^\circ$ ($\theta_h = 75^\circ$): $T = 0.518W$

  • $\theta_v = 30^\circ$ ($\theta_h = 60^\circ$): $T = 0.577W$

  • $\theta_v = 45^\circ$ ($\theta_h = 45^\circ$): $T = 0.707W$

This provides a direct justification for allowing lines up to 15 degrees off vertical when headroom and rigging geometry require it: tension increase is modest, but must still be checked against rated capacities.

8.6 Rigging Deflection and Geometry Drift

For each pick stage, check not only nominal angle but angle after deformation/rotation:

  • Panel rotation changes effective pick geometry

  • Sling stretch and shackle rotation can change load share

  • Equalizer beam deflection can redistribute reactions

8.6.1 Angle Change from Pick-Point Spread During Rotation

As the panel rotates from flat (0°) toward vertical (90°), the vertical projection of the distance between inserts changes. For a symmetric two-insert arrangement with horizontal insert separation $s$ at cast position:

$$ d(\phi) = \sqrt{s^2 \cos^2\phi + s^2 \sin^2\phi} = s $$

The insert separation distance $s$ is constant, but the effective horizontal spread to the rigging attachment point above changes as:

$$ x_{eff}(\phi) = \frac{s}{2} \cos(\delta - \phi) $$

Where:

  • $\phi$ is panel rotation angle from flat (0 = panel flat on casting slab, 90 = panel vertical)

  • $\delta$ is angle that the insert-to-insert line makes with the panel face

  • $x_{eff}$ is half the effective horizontal spread below the hook

The resulting sling angle from vertical at each stage:

$$ \theta_v(\phi) = \arctan\left(\frac{x_{eff}(\phi)}{L_{sling}}\right) $$

Where $L_{sling}$ is sling length from hook to insert.

Critical stage to check: The panel near-horizontal stage (small $\phi$) typically produces the largest $\theta_v$ (most off-vertical), which drives the highest leg tension.

8.6.2 Equalizer Beam Deflection Effect

For a symmetric equalizer beam of span $2a$ carrying two symmetric equal leg loads $T$, midspan deflection under load:

$$ \delta_{beam} = \frac{T \cdot a^3}{6EI} $$

This deflection shortens the effective vertical distance below the hook on the central connection by $\delta_{beam}$, which slightly steepens the effective sling angle. For well-designed beams (ASME BTH-1), this effect is small. When beam deflection exceeds $a/360$, recompute leg tension at loaded geometry.

8.6.3 Required Documentation for Deflection-Sensitive Picks

  • Nominal sling angles at each erection stage (ground break, mid-rotation, near-vertical, full vertical, set)

  • Predicted equalizer/spreader deflection under load

  • Recomputed insert and clutch demand at worst-case loaded geometry

  • Statement of whether load share changes exceed 5–10% from nominal assumptions

Do not use one static angle for all stages on 8- to 16-point picks. Stage-based geometry is required (ACI 551.1R §6 workflow intent).

9. Clutch Selection and Operation Controls

For each insert family, include a clutch control note in the erection package:

  • Approved clutch model by insert type and rated load class

  • Visual inspection criteria before use (deformation, wear, locking function)

  • Seating/engagement verification before line tension is applied

  • Prohibited conditions (mismatched insert family, damaged clutch, illegible rating)

  • Controlled release sequence after panel support and brace acceptance

Operational details remain manufacturer-specific (Dayton Superior, Meadow Burke, or approved equal). This guide should reference manufacturer instructions rather than replacing them.

10. Hold Points

Do not release rigging details until:

  • Insert manufacturer limits are verified

  • Angle and load share assumptions are signed off

  • Exceptional picks are called out in erection notes

11. Standards References

  • ASME B30.9 — Slings; rated capacity, horizontal angle reduction, inspection criteria, and minimum angle requirements

  • ASME B30.26 — Rigging hardware; shackles, master links, swivels, hooks — capacity ratings and required marking

  • ASME BTH-1 — Design of Below-the-Hook Lifting Devices; governs custom spreader and equalizer beam fabrication

  • OSHA 29 CFR 1926.251 — Rigging equipment for material handling; inspection, capacity labeling, and condition requirements

  • ACI 551.1R §6 — Panel CG calculation, pick load distribution, dynamic amplification factors, and rigging geometry adequacy checks

  • ACI 318 Ch. 17 — Concrete anchors; insert breakout capacity when verifying pick insert adequacy

  • ASME B30.5 — Crane operations and rated-load compliance at actual radius/boom configuration when rigging geometry changes between stages

12. TODO Project Fill-In

  • Add hardware families approved for this project

  • Add panel class to rigging profile mapping

  • Add lift-day inspection checklist