The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts. Author s : ACI Committee Publication: Technical Documents. Keywords: admixtures; aggregates; architectural concrete; coatings; cracking fracturing ; curing; deflection; design; drying shrinkage; fabrication; formwork; inspection; installation joints junction ; precast concrete panels; repairs; sandwich panels; sealants.
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If items found in these doc- any means, including the making of copies by any photo process, or by any elec- uments are desired to be part of the Project Documents, they tronic or mechanical device, printed or written or oral, or recording for sound or should be phrased in mandatory language and incorporated visual reproduction or for use in any knowledge or retrieval system or device, into the Project Documents.
Although the focus is on precast Chapter 5-Panel fabrication and delivery, pg. Tilt-up concrete, as discussed by 5. Guidance 5. The panels may be either of the following types: Chapter 6-Installation, pg. Structural design 7. Smooth Chapter 8-References, pg. Panels 8. Metric conversion, pg. This can be particularly troublesome when parties 1. Concrete itself is easily has been published. Architectural precast panel use and construction of precast concrete structures. Since there are minimum design rangements for corrections to be made by the parties requirements and methods of design peculiar to precast involved prior to start of erection.
However, contract document specifi- practices but be consistent with Chapter 2 of this guide. It is essential that the different alternatives. Cleaning need 1. Since most precasters maintain an engineering staff sponsible for delivering clean panels.
After installation of to prepare shop drawings, the engineer-architect should panels, the responsibility for protecting panels from interact with this group to obtain constructive advice and soiling and staining during subsequent operations should suggestions concerning local practice, production details, appropriately be the responsibility of the general con- and manufacturing capabilities.
When possible, this dis- tractor. Once a job is released for - Clip angles, inserts, bolts, and miscellaneous metal bidding and the structural concepts have been estab- items are required for construction with precast panels. These items may be: 1. The engineer-. Specifications should indicate who is responsible for ings, and to resist other loads that occur during stripping, the supply and installation of hardware.
When the sup- handling, shipping and erection. In this case, it is porting frame is structural steel, erection hardware is common for the contract documents to require that the normally supplied and installed by the precast erector or design calculations and erection drawings provided by the steel fabricator. When the building frame consists of cast- panel manufacturer be signed by a professional engineer in-place concrete, hardware is normally supplied by the who is either retained or employed by the manufacturer.
Detailed hardware layout is prepared by the precast prepared by the engineer-architect should show the con- manufacturer for approval by the engineer-architect.
Oc- nections required and the load support points in suffi- casionally certain special inserts or sleeves are required cient detail to permit construction. Manufacturers, during for other trades. In these instances, the trade involved is the preparation of shop drawings, should be given the responsible for having such parts approved and delivered opportunity to redesign the connections if redesign will to the panel manufacturer in time for embedment in the achieve more economical details that facilitate manu- wall panels.
These must be accompanied by the engineer- facture or erection. Any deviation from or discre- surfaces and anchorages for precast elements. When a pancy in the approved erection drawings should be noted panel cannot be erected within tolerances specified in the by the erection contractor prior to the start of erection. Any adjust- facture precasting plant or at the job site for com- ments affecting structural performance must be approved parison.
Approved full-size panels should be allowed to by the engineer of record. No panel should be left in an be used in the completed structure. If full-size samples unsafe support condition.
When full-size sample tion 5. Approved for conformance with the contract docu- 2. No resubmissions necessary. Approved, as noted, for conformance with the con- forced concrete wall panels. Both load-bearing and non- tract documents. Not approved; revise and resubmit. Terms common to ACI but used in this chapter with special application to wall 1. The classes and types of panels small samples. Such samples should be at least 12 x 12 in. Each may be although larger samples may be desirable.
If both faces either prestressed or conventionally reinforced. Non-load-bearing panel cladding -A precast wall The manufacturer should submit samples to the gener- panel that transfers negligible load from other elements al contractor for approval of the engineer-architect, while of the structure; this type of panel is generally designed retaining duplicate samples.
If the sample is not approv- as a closure panel and must resist all applicable service ed, resubmissions should be made until approval is and factored loads from wind forces, seismic forces, ther- obtained.
Sample approval should be in writing with mally induced forces, forces from time-dependent defor- reference to the correct sample code number, or the mations, self weight and those forces resulting from approval may be written on the sample itself. These panels should establish the range of accep- to resist all applicable design loads in addition to those tability with respect to color and texture variations, listed for non-load-bearing panels.
Load-bearing panels surface defects and overall appearance. It should be also include panels designed to function as shear walls. Axial forces, bending moments and shear forces Hollow-core panel-A precast panel that has voids should be determined from a rational analysis of the within the thickness in one direction for the full length of structure. Sandwich panel-A precast panel consisting of two In lieu of the procedure described above, compression layers of concrete separated by a nonstructural insulating member design may be based on the approximate pro- core.
Ribbed panel-A precast panel consisting of a slab 2. For compression ACI requirements may be legally binding. Local stress concentrations in the vicinity of connec- d For precast wall panels considered to be pre- tions and applied loads must be considered. The average Sections Shear-ACI , Chapter 11 for both prestressed and Limits of reinforcement for precast wall panels should nonprestressed panels.
Two-way reinforcement is not required for some essen- tially one-way panels, such as hollow-core panels. Also the effects of secon- 2. The following sections explain how to determine the ef- 2. The effective thickness of a wall panel where Ig is the uncracked moment of inertia accounting with a noncomposite facing should not include the separ- for voids or ribs, if they exist. Lateral bracing should be attached to the compression 2. In such cases the effective thickness may 2.
Fatigue, impact if any , cracking, and in- shear transfer through the insulation core must not ex- plane lateral stability at service load conditions must be ceed the shear allowed by the strength of the insulating accounted for in design. In calculating the deflection, panel behavior. See Section 2. The effective width should be determined by dead load. Com- 2. If the geometry of the precast member they may not be visible to the naked eye.
It is the control is more like that of a two-way slab, flexural reinforce- and acceptability of these cracks that must be evaluated. Therefore, if the reinforcement is coated for exposed surface is to remain free of discernible cracks, corrosion resistance, wall panels containing cracks up to the maximum flexural tension in the member under loads 0. The value be acceptable. The limitation on crack size specified is of the tensile strength of concrete should be modified for structural reasons.
The esthetic limitation will depend according to ACI , Section On coarse textured surfaces, such as exposed ag- gregate concrete, and on smooth surfaces comparable to 2.
For smooth adequately seated and anchored by mechanical means surfaces of high quality it may be desirable to limit crack- capable of sustaining all loads and stresses that may be ing in interior panels to 0.
ACI 533R-11: Guide for Precast Concrete Wall Panels
533R-11 Guide for Precast Concrete Wall Panels
International Concrete Abstracts Portal