While many jurisdictions(states, counties, cities)around the United States

have just adopted or are consideringadoption of the 2000 edition of the In-ternational Building Code, the firstedition of a competing model buildingcode, NFPA 5000, is nearing comple-tion, with publication expected in theFall of 2002. Anticipating that thereaders of the PCI JOURNAL wouldhave an interest in the contents of theconcrete chapter of this emergingmodel code, an overall review of thecontents is provided here.

Current Status

The latest draft of the NFPA 5000Building Code is available for reviewand downloading at the NFPA websiteat www.NFPA.org. Public comments

on this draft submitted by the desig-nated deadline will be considered atthe NFPA Annual Meeting to be heldin Minneapolis during the week ofMay 20, 2002. Any modifications ap-proved at this meeting will be advisoryto the Standards Council of NFPA,which is scheduled to meet in Bostonin mid-July. The contents of the NFPA5000 Building Code are expected to befinalized at that meeting, with publica-tion expected in early Fall, 2002.

Overview

Chapter 40 on Concrete of theNFPA 5000 Building Code adopts the2002 edition of ACI 318, BuildingCode Requirements for StructuralConcrete, by reference.

Section 37.10 of NFPA 5000 re-quires that earthquake resistant design

of structures be in accordance withSection 9 of the 2002 edition of ASCE7, Minimum Design Loads for Build-ings and Other Structures. In somecases, ASCE 7 supplements its load-ing requirements with additional pro-visions intended to ensure satisfactoryperformance of structures when sub-jected to the design earthquake forcesgiven in Section 9 of the standard.These supplementary provisions are tobe found in Section A.9 of ASCE 7,with those specifically related to con-crete being given in Section A.9.9.

In some cases, the terminology usedin ASCE 7 is not consistent with thatused in ACI 318, and provisions inSection A.9.9 coordinate these differ-ences. Other provisions in SectionA.9.9 deal with issues related to, ortypes of, seismic-force-resisting sys-tems that are not addressed in ACI

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The Concrete Design andConstruction Provisions of theNFPA 5000 Building Code

S. K. Ghosh, Ph.D.PresidentS. K. Ghosh Associates, Inc.Northbrook, Illinois

This article presents an overview of Chapter 40 onConcrete of the NFPA 5000 Building Code which,when published in the Fall of 2002 by the NationalFire Protection Association, based in Quincy,Massachusetts, will be competing with the 2000 and2003 editions of the International Building Code foradoption by various jurisdictions.

318. In a very small number of cases,it has also been determined that certainprovisions of ACI 318 need to bemodified to comply with the intent ofSection 9 of ASCE 7. These modifica-tions are also to be found in SectionA.9.9. Exactly two modifications toSection A.9.9 of ASCE 7-02 havebeen made in Chapter 40 of NFPA5000, because the timing of the ACI318 and ASCE 7 update processes didnot permit the two documents to becompletely coordinated.

NFPA 5000 makes one additionalmodification to the seismic detailingrequirements in Chapter 21 of ACI318-02.

Chapter 40 of NFPA 5000 has alsoadded provisions in areas not covered,or at least not comprehensively cov-ered, by ACI 318-02. These areas are:(1) slabs-on-ground; (2) concrete onsteel form deck; (3) concrete piles,piers, and caissons; (4) shotcrete; and(5) reinforced gypsum concrete.

Section 40.1 – Scope

Conventional reinforced concrete(made using portland cement orblended cements) as well as cast-in-place reinforced gypsum concrete isincluded in the scope of Chapter 40.

Section 40.2 – General

The design and construction of cast-in-place or precast structural elementsof plain or reinforced concrete, in-cluding prestressed concrete, are re-quired to comply with ACI 318-02,unless modified by other provisions ofChapter 40. Two exceptions are made.The following are permitted to be de-signed and constructed in accordancewith the provisions of PCA EB118,Prescriptive Method for InsulatingConcrete Forms in Residential Con-struction, provided that the buildingmeets the limitations of Table 1.1 ofthat document:

(1) Basement, foundation, andabove-grade walls of one- andtwo-family dwellings using insu-lating concrete forms (ICF), and

(2) Basement, foundation, andabove-grade walls of one- andtwo-family dwellings using con-ventional forms with flat sur-faces.

May-June 2002 105

Concrete on Steel Form Deck – Inmany buildings with structural steelframing, concrete floor and roof slabs arecast on stay-in-place steel form deck.

Where the steel deck serves only asthe form for the concrete and remainsin place after the concrete hardens, it isreferred to as a non-composite deck.The design and construction of con-crete slabs cast on such decks are re-quired to comply with the provisionsof ACI 318.

Where the steel deck serves as theform for the concrete, remains in placeafter the concrete hardens, and servesas the positive moment reinforcementfor the slab, it is referred to as a com-posite deck. The design and construc-tion of concrete slabs cast on suchdecks are required to comply with theprovisions of ASCE 3 Standard for theStructural Design of Composite Slabs.Concrete used in the construction ofsuch slabs is required to comply withthe applicable portions of Chapters 1through 7 of ACI 318.

Concrete Piles, Piers and Caissons– Chapter 39 of NFPA 5000 regulatesthe design and construction of deepfoundations, as long as the soil is capa-ble of providing adequate lateral sup-port to the foundation.

Portions of concrete piles, piers, andcaissons in soil not capable of provid-ing lateral support, or in air or water,must comply with the provisions ofACI 318.

The 1999 edition of ACI 318 for thefirst time included special seismic de-tailing requirements for certain foun-dation elements, including deep foun-dations. These requirements apply onlyto structures assigned to Seismic De-sign Category D, E, or F, and must becomplied with if a structure is assignedto one of these seismic design cate-gories. Section A.9.7 of ASCE 7 alsohas special detailing requirements forfoundations of structures assigned toSeismic Design Categories C, D, E orF. In case of conflicting provisions,those of NFPA 5000 (Chapter 30) andASCE 7 (Section A.9.7) would apply.

Section 40.3 – Construction Documents

For information that is required to beshown on construction documents, this

section simply refers the user to Sec-tion 1.2.1 of ACI 318.

Section 40.4 – Quality Assurance

Sections 38.3.7 and 38.3.8 of NFPA5000 provide requirements concerningquality assurance of concrete con-struction.

Section 40.5 – Seismic Requirements

This section makes two modifica-tions to the supplementary provisionsof Section A.9.9 of ASCE 7-02, to en-able use, under the NFPA 5000 Build-ing Code, of the new precast structuralsystems provision introduced in Chap-ter 21 of ACI 318-02.

The first modification classifies“special reinforced concrete structuralwalls” and the new “special precaststructural walls” as “special reinforcedconcrete shear walls.” Special precaststructural walls can thus be designedutilizing the existing design parame-ters and height limitations applicableto special reinforced concrete struc-tural walls. The only difference be-tween a cast-in-place special rein-forced concrete structural wall and thenew special precast structural wall isthat connections between precast wallpanels and between precast wall panelsand the foundation must comply withSections 21.13.2 and 21.13.3 of ACI318-02.

The second modification recognizesthe new “intermediate structural wall”and states that, in buildings assigned toSeismic Design Category C, ordinaryreinforced concrete shear walls con-structed of precast concrete elementsmust comply with the additional re-quirements of Section 21.13 of ACI 318for intermediate precast concrete struc-tural walls. Intermediate precast struc-tural walls may thus be designed utiliz-ing the existing design parameters andheight limitations applicable to ordinaryreinforced concrete structural walls.The only difference between a cast-in-place ordinary reinforced concretestructural wall and the new intermediateprecast structural wall is that connec-tions between precast wall panels andbetween precast wall panels and thefoundation must comply with Sections21.13.2 and 21.13.3 of ACI 318-02.

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Section 40.6 – Modifications to ACI 318

This section makes just one modifi-cation to Chapter 21 of ACI 318-02. Itapplies to columns of frames that aredesigned to be not part of the lateral-force-resisting system (so-called grav-ity frames) of a building assigned toSeismic Design Category D, E, or F.The modification exempts the require-ment that lap splices of longitudinalreinforcement in such columns be con-fined to the middle half of the columnheight. This would permit lap splicesof longitudinal column reinforcementjust above the floor levels, where theyare normally placed in non-seismicconstruction.

Section 40.7 – Slabs-on-Ground

Durability – Concrete used inslabs-on-ground is required to complywith the durability requirements inChapter 4 of ACI 318-02.

Minimum Thickness – The mini-mum thickness of slabs-on-ground isrequired to be 31/2 in. (90 mm).

Vapor Retarder – A vapor retarderhaving a perm rating not exceeding0.5 or a 6-mil (0.15 mm) thickness ofpolyethylene is required to be placedbetween the top of the subgrade orbase material and the bottom of a slab-on-ground.

Joints in the vapor retarder are re-quired to be lapped a minimum of 6in. (150 mm).

A vapor retarder is not required tobe provided under certain conditionsthat are spelled out.

Section 40.8 – Shotcrete

Shotcrete is defined as concrete ormortar thrust pneumatically at highvelocity onto a surface.

Specifications for shotcrete are re-quired to comply with the ACI 506.2,Specification for Shotcrete. Becauseof this requirement, if a project regu-lated by NFPA 5000 would involvethe use of shotcrete, the project speci-fications must include wording such

as: “Shotcrete shall conform to all therequirements of ACI 506.2, except asmodified by these contract docu-ments.”

Section 40.9 – Reinforced Gypsum Concrete

Materials used in reinforced gypsumconcrete are required to comply withASTM C 317, Standard Specificationfor Gypsum Concrete.

Gypsum concrete is made from adry mill-mixed product that is formu-lated and packaged based on the re-quirements of ASTM C 317. Thepackaged material may also containaggregate, which may consist of natu-ral or manufactured sand, perlite orvermiculite. Wood chips or shavingsmay also be added at times.

Regardless of whether aggregate isintroduced at the mill or at the site, itmust be of one of the types permittedby ASTM C 317. On site, the pack-aged material is mixed with aggregate,if not already included, and water toproduce a slurry that is poured in placeover reinforcing mesh and formboardssupported by subpurlins or primaryframing members.

The design and installation of cast-in-place reinforced gypsum concrete isrequired to be in accordance withASTM C 956, Standard Specificationfor Installation of Cast-in-Place Rein-forced Gypsum Concrete, which inturn requires that the design of rein-forced gypsum concrete be performedin accordance with the principles ofreinforced concrete design embodiedin ACI 318. Since allowable stressesfor the gypsum concrete and reinforce-ment are given in ASTM C 956, andsince Appendix A (Alternative DesignMethod, similar to working stress de-sign) of the last several editions ofACI 318 has been deleted from the2002 edition, the design professionalwill need to use Appendix A of ACI318-99 or an earlier edition of ACI318.

Precast gypsum concrete is allowedto be used only where approved.

Limitations of Use – Cast-in-placereinforced gypsum concrete is re-quired to be constructed with nonab-sorptive formboard or surfacing whereused for either of the following:

(1) For occupancies producing un-usually high humidities.

(2) For ceilings of structures notcompletely enclosed.

Concentrated loads, such as fromwater tanks, fan bases, cooling towers,flagpoles, and signs, are required to betransmitted directly to the primaryroof framing members, walls, or foot-ings.

Testing – Testing of gypsum con-crete is required to be in accordancewith the criterion set forth in ASTM C472, Standard Test Methods for Physi-cal Testing of Gypsum, Gypsum Plas-ters and Gypsum Concrete.

One test of each day’s pour of cast-in-place gypsum concrete is requiredto be made and the results thereof arerequired to be reported to the authorityhaving jurisdiction.

Concluding Remarks

The NFPA 5000 Building Code re-quires the design and construction ofplain, reinforced and prestressed (cast-in-place as well as precast) concretestructures to be in accordance with theprovisions of ACI 318-02. Modifica-tions to ACI 318-02 are minor andsmall in number.

Provisions have been added in thefollowing areas not covered, or at leastnot comprehensively covered, by ACI318: (1) slabs-on-ground; (2) concreteon steel form deck; (3) concrete piles,piers, and caissons; (4) shotcrete; and(5) reinforced gypsum concrete.

Acknowledgment

Joseph J. Messersmith, Jr. of thePortland Cement Association providedvaluable information for this article,some of it in a written form, portionsof which have been paraphrased withhis kind permission. His contributionis gratefully acknowledged.