Prepared by PCI Committee on Precast Sandwich Wall Panels

1 1 State of the Art of Precast /Prestressed concrete Sandwich Wall Panels200 West Adams Street I Suite 2100 I Chicago, IL 60606-5230 Phone: 312-786-0300 I Fax: 312-621-1114 I D Losch* Patrick W. Hynes*Ray Andrews Browning*Paul Cardone*Ravi Devalapura*Rex Donahey*Sidney FreedmanHarry A. Gleich*Gerald GoettschePaul Kourajian*Jason Krohn (TAC liaison)Chris LeatonZhengsheng LiRobert Long*Donald MeinheitMichael MilkovitzBrian Miller Frank NadeauBrad NessetStephen PessikiDavid N. Peterson*Steven H. Peterson*Rene Quiroga*Scott Reay (secretary)William Richardson*Kim Seeber*Venkatesh SeshappaDonald Smith*Bryan Trimbath (subcommittee head)

2 * Karl TruderungMike WagnerCharles Wynings*Li Yan* Contributing author Chair during preparation Current chair of Committee PCI staff liaison State of the Art of Precast /Prestressed concrete Sandwich Wall PanelsSecond EditionPrepared byPCI Committee on Precast Sandwich Wall PanelsPREFACEThis report is an update of the original state-of-the-art report published in the March April and May June 1997 issues of the PCI The original report was later published as a reprint (JR-403). After the publication of the original report, the use of Precast /prestressed concrete Sandwich wall Panels became more widespread in the United States.

3 Also, the publication led to a better understanding of the proper use, performance, and technical aspects of these specialty on the interest in these Panels and the passage of time from the initial report, the Committee decided that an update to the state-of-the-art report was a necessary intermediate step prior to the preparation of a recommended practice Committee report. This report updates both the text and the associated design examples to current codes and design practices. In addition, newer, more-applicable photographs of the manufacturing process and completed, in-place Panels have replaced the previous photographs.

4 PCI Committee Report2 State of the Art of Precast /Prestressed concrete Sandwich Wall Panels200 West Adams Street I Suite 2100 I Chicago, IL 60606-5230 Phone: 312-786-0300 I Fax: 312-621-1114 I 7 Erection of Sandwich Panels Panel handling and jobsite storage Panel erection Panel bracingCHAPTER 8 Inspection of Sandwich Panels Plant inspection Jobsite inspectionReferencesBibliographyAppendix Design Examples A1 Noncomposite cladding panel A2 Noncomposite load-bearing panel A3 Noncomposite shear wall panel A4 Composite cladding panel A5 Composite load-bearing panelCONTENTSN otationCHAPTER 1 General History Materials Advantages Description of panel types ApplicationsCHAPTER 2 Design

5 And Detailing Considerations General information Wythe thickness and size of prestressing strand Strand location and force Wythe connectors Panel width, thickness, and span Bowing Flexural design Load-bearing design Shear wall considerations External connections Detailing considerations Reinforcement requirements Fire resistanceCHAPTER 3 Insulation and Thermal Performance General information Insulation types Energy performance Calculation proceduresCHAPTER 4 Manufacture of Sandwich Panels General Stressing and strand positioning Methods of casting DetensioningCHAPTER 5 Product Tolerances, Cracking.

6 And Repairs Tolerances Cracking RepairsChapter 6 Handling, Shipping, and Storage of Sandwich Panels Panel length and width Panel stripping Shipping Panel storage3 State of the Art of Precast /Prestressed concrete Sandwich Wall Panels200 West Adams Street I Suite 2100 I Chicago, IL 60606-5230 Phone: 312-786-0300 I Fax: 312-621-1114 I = depth of equivalent rectangular stress blocka = width of panel being strippedA = area of concrete at cross section consideredAb = area of reinforcing bar or studAcr = area of crack interfaceAps = area of prestressed steel in tension zoneAs = area of mild-steel reinforcementAvf = area of shear-friction reinforcementb = width of compression face of memberb = length of panel being strippedb = clear span of panelbp = height of parapetc = distance from extreme fiber to neutral axisC = resultant compressive forceC = coefficient of thermal expansionCu =

7 Factored compressive forceCw = stud group adjustment factordp = distance from compression fiber to centroid of pre-stressed reinforcementD = dead loade = eccentricity of panel section at midheight, due to out of plumbness, thermal bow, and load effects, relative to ultimate design load (for P-D analysis) eP = eccentricity of axial roof or floor load on panel, or prestressing force measured from centroid of sectionEc = modulus of elasticity of concreteEI = flexural stiffness of compression memberf = net stress on concrete cross sectionfa = unit stress of structural steelfb = bending stress due to stripping.

8 Subscript denotes directionfbv = bending stress during the erection of the panelf'c = specified compressive strength of concretef'ci = concrete compressive strength at time consideredfpc = concrete compressive stress in concrete at centroid of cross section due to prestress (after allowance for all prestress losses)fps = stress in prestressed reinforcementfpu = specified tensile strength of prestressing steelfr = modulus of rupture of concretefw = resultant stress on weldFa = allowable bending stress of structural steelFh = resultant horizontal shear forceFw = design strength of weldFy = yield strength of structural steelh = total depth of sectionh1 = overall depth of the composite panel sectionh2 = insulation thickness within the composite panel sectionHu = factored load reaction in horizontal directionI = moment of inertia of section resisting external loadsIg = moment of

9 Inertia of gross sectionIp = polar moment of inertiaIxx,Iyy = moment of inertia of weld group with respect to its own x and y axes, respectivelyK'u = coefficient = Mu(12,000)/bd2pl = clear span lengthld = development lengthle = embedment lengthlw = length of weldL = live loadLR = roof live loadM = unfactored service load momentMcr = cracking momentMn = nominal moment strength at sectionMu = factored moment due to applied loadsMx = moment due to stripping with respect to x axisMy = moment due to stripping with respect to y axisP = applied axial loadP = total prestress force after lossesPc = nominal tensile strength of concrete elementPn = nominal axial load capacityPs = nominal tensile strength of steel elementPu = factored applied axial loadq

10 = load per unitQ = statical moment about neutral axisQE = effect of horizontal seismic (earthquake-induced) forcesr = radius of gyration at cross section of a compression memberR = fire endurance of composite assemblyR = roof live loadR1R2R3 = fire endurance of individual course4 State of the Art of Precast /Prestressed concrete Sandwich Wall Panels200 West Adams Street I Suite 2100 I Chicago, IL 60606-5230 Phone: 312-786-0300 I Fax: 312-621-1114 I = reaction due to dead loadRu = reaction due to total factored loadS = section modulusSDS = design, 5% damped, spectral response acceleration parameter at short periodsSw = section modulus of weld groupt = thickness of sectiontns = thickness of fascia wythe (typically outer wythe)ts = thickness of structural wythe (typically inner wythe)