ACI Tilt-Up Supervisor flashcards
ACI Tilt-Up Supervisor · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Casting bed flatness tolerance
- A common requirement is 1/4 in. deviation in 10 ft measured with a straightedge. Beds outside this tolerance produce panel bow and misalignment at erection.
- Bond breaker purpose
- A coating applied to the casting surface that prevents concrete from bonding to the bed. It is applied at the manufacturer's coverage rate, often in two perpendicular coats.
- Panel thickness tolerance
- Typically plus or minus 1/4 in. from the specified thickness. It is verified at multiple perimeter points before and after concrete placement.
- Panel plumb tolerance
- Commonly 1/4 in. in 10 ft of panel height. Final plumb is checked after all braces are installed and snugged.
- Lifting insert design factor
- Lifting hardware is commonly designed with a 2:1 factor on the static panel load to account for dynamic effects during the pick.
- Panel weight calculation
- Panel weight equals volume times concrete unit weight, typically 150 lb per cubic foot. Embeds, insulation, and finishes are added to the total.
- Center of gravity balance
- Lifting points are placed symmetrically about the panel centroid so the panel hangs level. An unbalanced pick causes rotation and loss of control.
- Spreader beam use
- A rigging member that keeps slings vertical or at a favorable angle, reducing compression and bending induced in the panel during lifting.
- Brace angle efficiency
- Braces are most efficient near 45 degrees from horizontal. Angles steeper than 60 degrees reduce the brace's resistance to lateral load.
- Two-brace minimum
- At least two braces per panel are common, with three for tall or narrow panels. Braces are snugged before the crane releases the load.
- Crane load chart use
- Capacity is read at the actual lifting radius, not the maximum radius. The load includes panel weight plus rigging and hardware weight.
- Outrigger ground pressure
- Crane outrigger loads are distributed through mats or cribbing. Ground bearing pressure must not exceed the verified soil capacity.
- Tag line control
- A rope used to control panel rotation during the lift. Personnel handling tag lines stay clear of the panel's swing path and the exclusion zone.
- Job hazard analysis
- A document listing tasks, hazards, controls, and responsible persons. It is reviewed with the crew before work begins each shift.
- Lift strength verification
- Panels are lifted only after field-cured cylinders or maturity testing confirm the concrete meets the lift design strength, often 75 percent of design.
- Vapor retarder laps
- A 10-15 mil sheet under slabs with sealed laps. Punctures are repaired before concrete placement to preserve the moisture barrier.
- Edge form bracing
- Edge forms are braced to resist concrete pressure and must not deflect more than about 1/8 in. under placement loads.
- Chamfer strip location
- A chamfer strip is set on the exposed face side of the edge form, typically 3/4 in., to produce the specified edge detail.
- Reveal strip placement
- Reveal and rustication strips are attached to the casting surface, not the edge form, so the profile appears on the exposed face.
- Embed location tolerance
- Commonly plus or minus 1/2 in. in plan unless the connection design requires tighter. Embeds are verified against templates before placement.
- Brace anchor embed height
- Brace anchor embeds are set at the heights shown on the bracing plan. Location error changes the brace angle and the load it carries.
- Exposed face cover
- Reinforcement cover on the exposed face depends on exposure class, typically 3/4 in. to 1-1/2 in. for tilt-up panels.
- Concrete slump range
- Tilt-up panels commonly use 4-6 in. slump unless a plasticizer is approved. Slump is checked against the approved mix design.
- Evaporation rate threshold
- An evaporation rate above 0.2 lb per square foot per hour indicates a need for hot-weather placement and curing precautions.
- Cold-weather concrete limit
- Protection is required when ambient temperature falls below 40 F unless the specification states otherwise. Panels are not lifted until strength is verified.
- Casting bed layout rule
- Panels are placed so all lift points fall within the crane's rated radius at both minimum and maximum reach used in the lift plan.
- Erection sequence principle
- Panels cast farthest from the building footprint are typically erected first when the crane must reach over them to access nearer panels.
- Panel identification marks
- Marks are placed on the non-exposed face and must match erection drawings. Orientation arrows ensure the correct face is set outward.
- Anchor bolt tolerance
- Cast-in anchor bolts are set from survey control, commonly within 1/4 in. horizontal unless structural drawings specify tighter.
- Brace removal condition
- Temporary braces are removed only after the permanent structural connection is completed and approved by the engineer of record.
- Exclusion zone rule
- No personnel stand or walk under a suspended panel. The zone is marked and enforced for the duration of the lift.
- Nonconforming panel disposition
- A panel outside tolerance is documented and dispositioned by the engineer of record. Repair procedures are approved before any repair work begins.