ACI Tilt-Up Supervisor common mistakes
ACI Tilt-Up Supervisor · Understand the traps and how to avoid them.
Treating the panel casting bed as a flat, forgiving surface and approving it without verifying subgrade compaction, moisture conditioning, and elevation tolerance against the planned casting geometry.
Candidates carry over slab-on-grade intuition, where minor deviations are absorbed by finish thickness, and underestimate how casting-bed irregularities propagate into panel bow, twist, and mismatched joints after erection.
What to do instead
Walk a documented bed checklist: verify compaction test results, moisture conditioning, grade stakes at a defined grid, and flatness measured with a straightedge or laser before forms are set. Record deviations against the project tolerance and require correction before formwork.
Setting edge forms and blockouts to nominal dimensions without accounting for reveal depth, chamfer, rustication, or panel-to-panel joint width when laying out geometry.
Candidates read the architectural plan dimension as the form line dimension and forget that reveals and joint gaps are subtracted from the panel face, so every panel is sized slightly wrong in a consistent direction.
What to do instead
Convert architectural dimensions to form-line dimensions on a marked-up layout drawing before setting any form, showing reveal offsets and joint widths explicitly. Cross-check the first panel's as-set dimensions against that drawing before casting.
Verifying only that the specified number of inserts and embeds are present, without checking type, orientation, embedment depth, edge distance, or that lift and brace locations match the approved lifting and bracing drawings.
Candidates treat hardware as a counting exercise and do not connect insert position to the rigging and bracing plan, so a correctly counted but mislocated insert passes inspection.
What to do instead
Inspect against the lifting and bracing drawings, not the count alone: confirm insert type, orientation, embedment, edge distance, and that each location corresponds to the planned lift point or brace point. Flag any field relocation for engineering review before casting.
Approving a lift plan that lists crane capacity and rigging hardware but omits panel weight build-up, rigging weight, dynamic and suction allowances, and the crane's capacity at the actual radius and boom configuration.
Candidates anchor on the hardware list and the panel's nominal weight, then accept the plan without checking the load chart at the real pick geometry, where capacity is often far lower than at the chart's favorable radius.
What to do instead
Recompute the lift: panel volume times concrete density, plus embeds, rigging, and a defined dynamic allowance, then compare against the load chart at the worst-case radius and configuration for the entire pick path. Reject plans missing any of these terms.
Treating bracing as a post-erection formality and permitting panels to stand free or with temporary bracing not yet tightened, plumbed, and anchored to a designed reaction point.
Candidates see the panel standing stable and assume the critical moment has passed, but an unbraced or partially braced panel is at its highest risk before final connections and brace anchor capacity are verified.
What to do instead
Enforce a sequence where no lifting hardware is released until the specified number of braces are installed, plumbed, and anchored to a substrate with verified capacity. Confirm brace anchor design and inspection sign-off before the crane moves on.
Writing a job hazard analysis that lists generic hazards such as falls and struck-by without tying each to the specific task sequence, panel geometry, crane swing path, or access route on this site.
Candidates reproduce boilerplate hazard lists because that is what a JHA looks like on paper, and never connect hazards to the actual lift plan, exclusion zone, or sequence of operations.
What to do instead
Build the JHA task by task in erection sequence, naming the specific hazard, the control, and the responsible person for each step. Map the crane swing path and exclusion zone on a site sketch and reference it in the JHA.
Checking tolerances with a single measurement or at a single location and declaring the element in tolerance, without sampling the full extent of the panel, slab, or foundation.
Candidates take a spot reading that happens to fall in tolerance and stop, missing systematic bow, twist, or elevation drift that only appears when measurements are distributed across the element.
What to do instead
Apply the project's sampling pattern: multiple readings across length and width, at defined intervals, recorded on a tolerance form. Compare each reading to the stated tolerance and document any out-of-tolerance location with its corrective action.
Planning concrete placement around the specified slump and mix design without adjusting for ambient temperature, wind, delivery time, and admixture performance at the time of the pour.
Candidates treat the mix design as fixed and assume the batch arriving on site will behave as specified, then face rapid stiffening, cold joints, or finishing problems they did not plan for.
What to do instead
Review the mix with the supplier against the day's forecast and haul time, confirm admixture dosing and any approved retempering rules, and plan placement rate, crew size, and finishing window accordingly. Reject loads outside the approved slump and time limits.
Approving the foundation or slab layout from a single control point or one dimension chain, without closing the layout back to a second control point or checking diagonal dimensions.
Candidates trust the total station reading or the tape chain and skip the closure check, so a small angular error or a misread dimension propagates across the panel line and is only discovered at erection.
What to do instead
Close every layout: check diagonals, verify dimensions from at least two independent control points, and compare against the setting-out drawing before concrete is placed. Record the closure check on the layout record.
Treating inspection as a final walk before the pour rather than a series of hold points for formwork, reinforcement, embeds, and pre-lift conditions.
Candidates compress inspection into one end-stage event because that matches how the schedule is presented, so defects hidden by the next operation (covered reinforcement, buried embeds, closed forms) are never seen.
What to do instead
Define and enforce hold points: bed and layout, formwork geometry, reinforcement and cover, embeds and inserts, pre-pour, and pre-lift. No subsequent operation proceeds without a signed inspection at each hold point.