1 Scope
NOTE This Section covers site-cast tilt-up concrete wall panels cast horizontally on the project slab or a dedicated casting bed, lifted into final vertical position, and braced until permanently connected to the completed structural frame. (1.1)
NOTE Tilt-up panels are classified as site-cast (cast-in-place) concrete under ACI 318 and the IBC, not as off-site precast. This classification governs which special inspection, submittal, and permit requirements apply, and it is the reason tilt-up work is specified separately from manufactured precast. (1.2)
1.3Work of this Section includes panel design and detailing, casting bed preparation, bond breaker, embedded lifting and bracing inserts, temporary bracing, panel-to-foundation and panel-to-diaphragm connections, reveals, and finishes.
1.4The Contractor shall coordinate tilt-up panel work with the foundation, structural steel, roof deck, and slab-on-grade trades so that erection, bracing, and final tie-in proceed without conflict.
NOTE Off-site manufactured precast members, including prestressed double-tees, hollowcore planks, and precast spandrels, are specified in
Precast Concrete and are not part of this Section.
(1.5) NOTE Reinforcing bar, welded wire reinforcement, and post-tensioning material are specified in
Concrete Reinforcement and are referenced here only by use.
(1.7) NOTE Non-shrink grout for base-of-panel grouted connections is specified in
Non Shrink Grout and is incorporated here by reference only.
(1.9) 2 Referenced Standards
2.1Materials, design, and construction shall comply with the latest adopted edition of each of the following unless a specific edition is cited or the Authority Having Jurisdiction adopts a different edition.
2.2Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard |
Title |
| ACI 551.1R-14 |
Guide to Tilt-Up Concrete Construction |
| ACI 551.2R-15 |
Design Guide for Tilt-Up Concrete Panels |
| ACI 318-19 |
Building Code Requirements for Structural Concrete and Commentary |
| IBC 2021 |
International Building Code, Chapter 19 (Concrete) |
| ASCE 7-22 |
Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
| ASTM C33 |
Concrete Aggregates |
| ASTM C31 |
Making and Curing Concrete Test Specimens in the Field |
| ASTM C39 |
Compressive Strength of Cylindrical Concrete Specimens |
| ASTM A615/A615M |
Deformed and Plain Steel Bars for Concrete Reinforcement |
| ASTM A1064/A1064M |
Carbon-Steel Wire and Welded Wire Reinforcement for Concrete |
| ASTM C309 |
Liquid Membrane-Forming Compounds for Curing Concrete |
| OSHA 29 CFR 1926.704 |
Requirements for Precast/Tilt-Up Concrete Erection |
NOTE Tilt-up panels are governed by ACI 318 as adopted by IBC Section 1901.2; some jurisdictions remain on the 2018 IBC with ACI 318-14. (2.3)
2.4The Contractor shall verify the adopted edition of each referenced standard with the Authority Having Jurisdiction.
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following action submittals for review before fabrication or panel casting begins:
- Concrete mix designs for panels and for the casting bed, with aggregate, cement, admixture, and trial-batch or historical strength data
- Panel shop drawings showing dimensions, reveals, openings, embeds, reinforcement, and lift and brace insert locations
- Lifting and bracing design drawings, signed and sealed by the lift/brace engineer, showing insert layout, rigging geometry, brace count and spacing, and release sequence
- Reinforcement placing drawings coordinated with reveal geometry and required concrete cover
- Bond breaker and curing compound product data with manufacturer compatibility confirmation
- Insulation and shear-connector data for insulated sandwich panels, including connector layout and thermal analysis
- Connection details for panel-to-foundation, panel-to-panel, and panel-to-diaphragm joints
- Erection plan showing panel sequence, crane position, casting bed layout, and stacking arrangement
☑ Panel and casting bed mix designs
☑ Panel shop drawings
☑ Lift and brace engineering (signed/sealed)
☑ Reinforcement placing drawings
☑ Bond breaker and curing compound data
☐ Sandwich panel insulation and connector data
☑ Connection details
☑ Erection plan
3.1.2Lifting and bracing design drawings shall be signed and sealed by a Professional Engineer retained by the Contractor, independent of the structural Engineer of Record.
3.1.3Panel shop drawings shall identify each panel by a unique mark keyed to the erection plan.
3.2.1The Contractor shall submit the following informational submittals:
- Qualifications of the tilt-up erector and of the lift/brace engineer
- Concrete strength test reports for panels and casting bed per ASTM C39
- Bond breaker application records, including coats applied and re-application after weather exposure
- Embedded insert manufacturer certifications and rated working loads
- Special inspection reports for concrete placement and panel erection
☑ Erector and lift/brace engineer qualifications
☑ Concrete strength test reports
☑ Bond breaker application records
☑ Insert manufacturer certifications
☑ Special inspection reports
3.3 Closeout Submittals
3.3.1The Contractor shall submit the following closeout submittals before final acceptance:
- Record drawings showing as-built panel layout, embed locations, and connection details
- Sealant and joint product data and warranty documentation
- Concrete finish and coating maintenance instructions
☑ Record drawings
☑ Sealant and joint warranty documentation
☑ Finish and coating maintenance instructions
4 Quality Assurance
NOTE Tilt-up construction concentrates risk into a few brief, irreversible moments. A panel cast on degraded bond breaker can bond to the slab and crack on lift; an underrated insert or a too-shallow sling angle can overload rigging during erection; an under-strength panel can fail before it is ever braced. The quality program therefore emphasizes strength verification at the time of lift, independent lift/brace engineering, and special inspection of the casting and erection operations. (4.1)
4.2 Lift and Brace Engineering
NOTE Most jurisdictions, including California, require lift and brace drawings signed and sealed by a Professional Engineer separate from the structural Engineer of Record; omitting this is a common source of RFIs and schedule delay. (4.2.1)
4.2.2Lifting and bracing systems shall be designed by a Professional Engineer retained by the Contractor.
4.2.3Lifting inserts shall be designed with a minimum factor of safety of 2:1 on the rated working load in accordance with OSHA 29 CFR 1926.704 and the insert manufacturer's published capacities.
4.2.4Rigging geometry, including sling angle and number of sling legs, shall be shown on the lift drawings and shall match the rigging actually used in the field.
4.2.5Sling legs shall be arranged so that the angle from horizontal is not less than the value below; shallower angles sharply increase insert tension.
4.2.6Temporary bracing shall be designed for the basic wind speed below, or the wind speed required by the Authority Having Jurisdiction, whichever is greater.
4.3 Strength Verification
NOTE A frequent and serious error is to specify only the 28-day design strength and leave the lift strength unstated; the strength a panel needs before erection is the value set by the lift engineer, typically about 3,000 psi, independent of the 28-day value. (4.3.1)
4.3.2Panels shall not be lifted until field-cured test specimens confirm the concrete has reached the minimum compressive strength required by the lift engineer.
4.3.3The minimum panel concrete strength at the time of lift shall be as scheduled below unless the lift engineer requires a higher value.
25004000
Default: 3000 psi
4.3.4Test specimens shall be made and cured in the field in accordance with ASTM C31 and tested in accordance with ASTM C39.
4.3.5A minimum of one set of compressive strength cylinders shall be taken for each day's panel casting and for each mix design.
4.4 Special Inspection
NOTE Tilt-up wall panels require special inspection under IBC 2021 Table 1705.3, including inspection of concrete placement; the scope, continuous or periodic, is set by the construction documents and the Authority Having Jurisdiction. (4.4.1)
4.4.2Concrete placement for panels shall receive continuous special inspection in accordance with IBC Table 1705.3.
4.4.3Embedded insert and reinforcement placement shall be inspected before concrete placement.
4.4.4Panel erection, including bracing installation and connection welding, shall be inspected in accordance with the approved statement of special inspections.
● Continuous during concrete placement and erection
○ Continuous placement, periodic erection
○ Periodic per approved statement of special inspections
4.5 Mockups and Qualifications
NOTE A finish mockup is the only reliable way to set acceptance criteria for as-cast color, texture, reveals, and form-liner profiles before production panels are committed. (4.5.1)
4.5.2Where an exposed architectural finish is specified, the Contractor shall cast a finish mockup panel for review and approval before casting production panels.
4.5.3Approved mockups shall establish the standard of acceptance for color, texture, reveal sharpness, and finish for the remainder of the work.
4.5.4The tilt-up erector shall have completed at least three projects of comparable panel size and building height.
5 Environmental and Service Conditions
NOTE Design loads, in particular wind and seismic, drive panel thickness and reinforcement and govern the out-of-plane anchorage of panels to the roof and floor diaphragms. (5.1)
5.2Panels and their connections shall be designed for the wind, seismic, and gravity loads determined in accordance with ASCE 7-22, coordinated with the slender-wall provisions of ACI 551.2R.
NOTE Buildings in Seismic Design Category C and higher require explicit out-of-plane wall-to-diaphragm anchorage under ASCE 7; this requirement is frequently overlooked in otherwise low-seismic jurisdictions when a building crosses the SDC threshold. (5.3)
5.4Out-of-plane anchorage of panels to the roof and floor diaphragms shall be provided where required by the Seismic Design Category.
Per drawings — structural general notes
NOTE Insulated sandwich panels develop thermal bow because the inner and outer wythes respond differently to temperature gradients; composite and non-composite assemblies bow by different amounts, and the connections must accommodate it. (5.5)
5.6Connections for insulated sandwich panels shall accommodate the differential thermal movement and bow predicted by the panel designer.
Per drawings — structural general notes
6 Materials
6.1 Concrete
NOTE Panel concrete f'c is most often 4,000 psi; tall panels and high-seismic conditions warrant 5,000 psi. The casting bed concrete is a separate mix and may be a lower strength, but it must be strong enough to carry the wet panel weight plus construction live load without distress. (6.1.1)
6.1.2Panel concrete shall attain the specified 28-day compressive strength below when tested in accordance with ASTM C39.
6.1.3Casting bed concrete shall attain the specified 28-day compressive strength below.
6.1.4Aggregates for panel concrete shall comply with ASTM C33.
6.1.5Maximum nominal coarse aggregate size shall be selected for the panel thickness and reinforcement spacing as scheduled below.
6.1.6Where panels receive an exposed architectural finish, aggregate and cement source shall be held constant across all panels in a single elevation to maintain color uniformity.
6.2 Reinforcement
NOTE Reinforcement is specified in detail in
Concrete Reinforcement; the selections below establish only the configuration and grade used in panels.
(6.2.1) 6.2.2Deformed reinforcing bar shall comply with ASTM A615/A615M, Grade 60.
6.2.3Welded wire reinforcement, where used in sandwich panel wythes or face shells, shall comply with ASTM A1064/A1064M.
6.2.4Wall reinforcement shall provide a minimum reinforcement ratio of 0.001 of the gross concrete area in each direction in accordance with ACI 318-19 Section 11.6.
6.2.5The panel reinforcement configuration shall be as scheduled below.
● Single mat, centered (#5 @ 16 in. each way)
○ Double mat (#5 @ 16 in. each way)
○ Double mat, heavy (#6 @ 18 in. each way)
6.2.6Additional reinforcement required to resist lifting and erection stresses shall be provided as determined by the lift engineer.
6.2.7Concrete cover to reinforcement shall be as scheduled below in accordance with ACI 318-19 Section 26.6.
6.3 Bond Breaker and Curing Compound
NOTE The bond breaker is the single most failure-prone material in tilt-up: too little and the panel bonds to the slab and cracks on lift; the wrong product and it reacts with the curing compound. Compatibility between the two must be confirmed in writing by both manufacturers. (6.3.1)
6.3.2The Contractor shall obtain written confirmation from both the bond breaker and curing compound manufacturers that the two products are compatible.
6.3.3Bond breaker shall be applied to the casting surface in not fewer than two coats.
6.3.4Bond breaker shall be re-applied where it has been washed by rain, otherwise disturbed, or where more than 30 days elapse before panels are cast.
6.3.5Curing compound, where used, shall comply with ASTM C309.
6.3.6The bond breaker type shall be as scheduled below; selection shall be coordinated with the curing compound and the casting surface condition.
● Water-based, spray-applied
○ Solvent/petroleum-based, spray-applied
○ Reactive chemical bond breaker
6.4 Embedded Hardware
NOTE Lifting inserts, brace inserts, weld plates, and ledger angle anchors are cast into the panel during the horizontal phase and cannot be relocated afterward; their layout is fixed by the lift and connection drawings. (6.4.1)
6.4.2Lifting and bracing inserts shall be a coordinated manufacturer system with published rated working loads and a documented factor of safety.
6.4.3Embedded weld plates and connection hardware shall be detailed on the panel shop drawings and located before concrete placement.
6.4.4Embedded steel exposed to weather or in contact with exterior concrete shall be hot-dip galvanized or otherwise corrosion-protected.
7 Panel Configuration
NOTE Panel configuration is the first major design decision and sets thickness, reinforcement, insulation, and lifting approach. The solid flat panel is the warehouse default; ribbed and sandwich configurations address tall-panel bending capacity and building-envelope performance respectively. (7.1)
7.2The panel configuration shall be as scheduled below.
● Solid flat panel
○ Ribbed / pilaster panel
○ Insulated sandwich panel, composite
○ Insulated sandwich panel, non-composite
NOTE Solid panels are cast monolithically at uniform thickness and are the most common configuration for warehouse and distribution buildings. Ribbed or pilaster panels add integral thickened ribs to increase out-of-plane bending capacity for tall panels while reducing concrete volume. (7.3)
7.4 Panel Thickness
NOTE Panel thickness is a function of panel height, wind and seismic demand, and insulation. The code floor is 5.5 in.; 7.25 in. is the workhorse for single-story warehouses with 24 to 32 ft eave heights, and 9 to 12 in. is typical for panels 40 to 55 ft tall or in high-seismic zones. (7.4.1)
7.4.2Panel thickness shall not be less than 5.5 in. in accordance with ACI 551.1R-14.
7.4.3Panel thickness shall be as scheduled below, subject to the panel designer's slender-wall analysis.
NOTE Multi-story and multi-lift panels are cast and erected as a single unit spanning more than one floor and require refined lifting analysis; punch-out panels carry pre-formed openings for dock doors, storefront, and fan penetrations cast during the horizontal phase. (7.5)
7.6Openings for dock doors, storefront, and equipment penetrations shall be formed during the horizontal casting phase and shown on the panel shop drawings.
7.7Opening locations shall be coordinated with the architectural and structural drawings. panel elevations 8 Insulated Sandwich Panels
NOTE A sandwich panel is two concrete wythes separated by a continuous foam core and tied together by shear connectors. In a composite panel the connectors make the wythes act together structurally; in a non-composite panel the exterior wythe is architectural cladding only and the interior wythe carries the structure. The distinction governs connector type, thickness, and thermal behavior. (8.1)
8.2 Insulation Core
NOTE Insulation type and R-value drive wythe thickness and connector selection; extruded polystyrene and polyisocyanurate are the common cores. (8.2.1)
8.2.2The insulation core type shall be as scheduled below.
● Extruded polystyrene (XPS)
○ Polyisocyanurate (polyiso)
8.2.3The minimum thermal resistance of the insulation core shall be as scheduled below.
530
Default: 13 ft²·°F·h/Btu
8.2.4The insulation core shall be continuous across the panel except where interrupted by structural ribs or solid zones required by the panel designer.
8.3 Shear Connectors
NOTE Shear connectors transfer load between wythes and define whether the panel behaves compositely; fiber-reinforced polymer connectors are standard because they minimize thermal bridging. (8.3.1)
8.3.2Shear connectors shall be a manufactured system with published shear and tension capacities and a documented composite or non-composite design basis.
8.3.3Connector layout shall be designed by the panel designer and shown on the panel shop drawings.
8.3.4The shear connector behavior shall be as scheduled below.
● Composite (wythes act together)
○ Non-composite (exterior wythe is cladding only)
9 Connections
NOTE Tilt-up connections fall into three families: panel-to-foundation at the base, panel-to-panel at vertical joints, and panel-to-diaphragm at the roof and floor. Each transfers a different force, and each must work both during temporary bracing and in the completed structure. (9.1)
9.2 Panel-to-Foundation
NOTE The base connection transfers gravity bearing and erection uplift into the footing or grade beam. A grout pad levels the panel and distributes bearing; cast-in dowels or hairpins develop uplift and shear. (9.2.1)
9.2.2Panels shall bear on a non-shrink grout pad placed in accordance with Non Shrink Grout. 9.2.4The panel-to-foundation connection method shall be as scheduled below.
● Cast-in hairpin/dowel into grade beam with grout pad
○ Weld plate to cast-in foundation plate with grout pad
○ Dry-pack base detail with dowels
9.3 Panel-to-Diaphragm
NOTE The roof and floor connection transfers diaphragm shear and collector forces and provides out-of-plane anchorage. It is usually a continuous ledger angle bolted or welded to embedded plates, with the deck or joists seated on the ledger. (9.3.1)
9.3.2Panels shall be connected to the roof and floor diaphragms to transfer diaphragm shear and collector forces as determined by the structural Engineer of Record.
9.3.3The panel-to-diaphragm connection type shall be as scheduled below.
● Continuous bolted ledger angle
○ Continuous welded ledger angle
○ Joist/purlin seat on embedded plate
9.3.4Ledger angle and embed locations shall be coordinated with the deck and joist layout. roof framing plan 9.4 Panel-to-Panel
NOTE Vertical joints between panels are closed with sealant and, where required for in-plane shear transfer, with welded plate connections or grout pockets. (9.4.1)
9.4.2Vertical panel joints shall be sealed in accordance with the Finishes and Joints requirements of this Section.
9.4.3Where in-plane shear transfer between adjacent panels is required, panels shall be connected with welded embedded plates or grouted pockets as determined by the structural Engineer of Record.
10 Casting and Erection
NOTE The casting bed is most often the building slab-on-grade, which was designed for forklift wheel loads, not for the temporary weight of a wet panel plus the crew and equipment that cast it. The casting bed strength and thickness must be verified for the casting condition before it is used. (10.1)
10.2The casting surface shall be verified to be adequate to carry the wet panel weight plus construction live load before panels are cast on it.
10.3 Casting Bed
10.3.1The casting surface shall be smooth, clean, and free of debris, curing-compound contamination, and surface defects that would telegraph into the panel face.
10.3.2The casting surface shall receive bond breaker in accordance with the Bond Breaker requirements of this Section.
10.3.3Reveal and rustication strips shall be secured to the casting surface and shown on the panel shop drawings before reinforcement is placed.
10.4 Erection Sequence
10.4.1Panels shall be erected in the sequence shown on the approved erection plan, coordinated with crane position and casting bed layout.
10.4.2Panels shall not be lifted until the strength verification requirements of this Section are satisfied.
10.4.3Each panel shall be braced immediately upon being set, before the rigging is released.
10.5 Temporary Bracing
NOTE Bracing holds each panel against wind and accidental loads from the moment it is set until the permanent diaphragm connections are complete. Brace count, spacing, and the brace-to-slab anchor are all set by the brace engineer. (10.5.1)
10.5.2Each panel shall receive at least one brace.
10.5.3Panels wider than 20 ft shall receive at least two braces, or more as required by the brace engineer.
10.5.4Braces shall be anchored to the slab using cast-in inserts where practicable; post-installed anchors in the casting slab shall be used only where the brace engineer permits and shall be designed for the brace reaction.
10.5.5Braces shall not be released until the permanent connections that replace their function are complete and inspected.
10.5.6The brace-to-slab anchorage method shall be as scheduled below.
● Cast-in insert in slab
○ Post-installed mechanical anchor
○ Post-installed adhesive anchor
11 Finishes and Joints
NOTE The exposed face of a tilt-up panel is the building's finished exterior, so finish and joint design carry both architectural and weatherproofing weight. Finish options run from as-cast smooth to form-liner textures; joints are sized for movement and sealed. (11.1)
11.2 Surface Finish
NOTE Deep rustication reveals can encroach on the minimum concrete cover to the nearest reinforcing bar; reveal geometry deeper than 1 in. must be checked against the reinforcement placing drawings. (11.2.1)
11.2.2Reveal depth shall be coordinated with reinforcement placement so that the minimum concrete cover is maintained at the bottom of every reveal.
11.2.3The exposed panel face finish shall be as scheduled below.
As-cast smooth
Broom finish
Sandblast (light/medium/heavy)
Acid etch
Form-liner texture
Paint over as-cast
11.2.4Reveal and rustication strips shall not be removed before lift in a manner that damages panel edges; the removal sequence shall be shown on the shop drawings.
11.3 Joints
NOTE Panel joints accommodate erection tolerance and thermal and structural movement; they are sized at 3/4 in. minimum, 1 in. typical, and sealed with a sealant qualified for a concrete substrate. (11.3.1)
11.3.2Panel joints shall be not less than 3/4 in. wide.
11.3.3The design panel joint width shall be as scheduled below.
11.3.4Joints shall be sealed with a sealant qualified by its manufacturer for use over a concrete substrate and for the joint movement range.
11.3.5Joint locations and reveal patterns shall be coordinated with the architectural elevations. panel elevations 12 Delivery, Storage, and Handling
NOTE Most tilt-up panels are cast on site and never transported, but inserts, hardware, insulation, and bond breaker arrive as delivered products and must be protected, and panels stacked or stored before erection must be supported to avoid cracking. (12.1)
12.2Lifting and bracing inserts, weld plates, and connection hardware shall be stored to prevent corrosion, damage, and loss of identification.
12.3Bond breaker and curing compound shall be stored in accordance with the manufacturer's temperature and shelf-life limits.
12.4Sandwich panel insulation shall be protected from sunlight, moisture, and physical damage before casting.
12.5Where panels are stored before erection, they shall be supported on dunnage at points that do not induce cracking, as determined by the panel designer.
13 Warranty
NOTE The warranty covers defects in the panel concrete, connections, finishes, and joint sealants; sealant and coating warranties typically run longer than the general workmanship warranty and are tracked separately. (13.1)
13.2The Contractor shall warrant the tilt-up panel work against defects in materials and workmanship for the period scheduled below.
13.3Joint sealant shall be warranted against adhesive and cohesive failure for the period scheduled below.
13.4Exterior coating or paint, where applied, shall be warranted for the period scheduled below.