ACI 318-14 Chile 2 Slides Per Page

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Building a New Code

Overview of Presentation

ACI Committee 318

A brief history of ACI 318 building code

Why reorganize?

How 318-14 is organized

Benefits

Available resources and process timetable

Some substantive technical changes

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ACI 318-14 Reorganization Process

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ACI Committee 318

Materials engineers Structural engineers Contractors Building officials Researchers

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www.concrete.org/ACI318 #ConcreteCode

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ACI Committee 318International Scope

Members of ACI Committee 318 represent the interests of and reside in the following countries:

Argentina Brazil Canada Chile Colombia Ecuador El Salvador

Guatemala Mexico Panama Peru Taiwan United States Venezuela

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Countries adopting ACI 318

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History 1904 Wilbur Wright makes first flight Puccini's "Madama Butterfly" premieres in Milan Federation Internationale de Football Association

forms in Paris Meat Massacre in Santiago Construction begins on Panama Canal ACI founded as National Association of Cement

Users

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1st Reinf. Conc. Code

February 1910

14 Pages

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Goal: Life Safety

History

Structural provisions of ACI 318 based on pseudo-working stress through 1956

Ultimate Strength approach firmly established in 1971 edition.

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Significant Changes from 1971 to 2011 : Development lengths Torsional strength Integrity reinforcement Seismic design and detailing Load & strength reduction factors Unified design provisions Concrete exposure classes Anchoring to concrete

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History


1971 Code had 750 provisions

Ten Code editions published since 1971

2011Code has more than 2,500 provisions

ACI 318-11 compared to ACI 318-71

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History

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ACI 318-11CHAPTER1GENERALREQUIREMENTSCHAPTER2NOTATIONANDDEFINITIONSCHAPTER3MATERIALSCHAPTER4DURABILITYREQUIREMENTSCHAPTER5CONCRETEQUALITY,MIXING,ANDPLACINGCHAPTER6FORMWORK,EMBEDDEDPIPES,CONSTRUCTIONJOINTSCHAPTER7DETAILSOFREINFORCEMENTCHAPTER8ANALYSISANDDESIGNGENERALCONSIDERATIONSCHAPTER9STRENGTHANDSERVICEABILITYREQUIREMENTSCHAPTER10FLEXUREANDAXIALLOADSCHAPTER11SHEARANDTORSIONCHAPTER12DEVELOPMENTANDSPLICESOFREINFORCEMENTCHAPTER13TWOWAYSLABSYSTEMSCHAPTER14WALLSCHAPTER15FOOTINGSCHAPTER16PRECASTCONCRETECHAPTER17COMPOSITECONCRETEFLEXURALMEMBERSCHAPTER18PRESTRESSEDCONCRETECHAPTER19SHELLSANDFOLDEDPLATEMEMBERSCHAPTER20STRENGTHEVALUATIONOFEXISTINGSTRUCTURESCHAPTER21EARTHQUAKERESISTANTSTRUCTURES

FlexuralandAxialStrength,ShearStrength,

StrengthReductionFactors,,

LapSplice,

Cover,

Ties,

TiesinJoint,Slope,

Chapter10Chapter11

Chapter9

12.1512.177.8.1.1

11.10.2

7.7

7.10.5

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11ACI 318-Organization

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ACI 318-11 organization cross referencing

18.1.2 All provisions of this Code not specifically excluded, and not in conflict with provisions of Chapter 18, shall apply to prestressed concrete.18.1.3 The following provisions of this Code shallnot apply to prestressed concrete, except as specifically noted: Sections 6.4.4, 7.6.5, 8.12.2, 8.12.3, 8.12.4, 8.13, 10.5, 10.6, 10.9.1, and 10.9.2; Chapter 13; and Sections 14.3, 14.5, and 14.6, except that certain sections of 10.6 apply as noted in 18.4.4.

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Need to find a tool?

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Need to find a tool?

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ACI continuously hears comments about ACI 318 in seminars, letters, etc.

In 2003: committee members began discussion In 2006: surveyed users

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ESurveyResultsOrganizationalItems: Engineerswantallrelatedinformation

foramembersdesignanddetailingeasilylocated

Engineerswantthecodetobeconfiguredparalleltohowtheydesignmembers


ACI continuously hears comments about ACI 318 in seminars, letters, etc.

In 2003: committee members began discussion In 2006: surveyed users

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: focus groups with practicing engineers In 2007: a two day workshop

: an outline was developed In 2008: committee approved effort

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The beginning of a marathon

The end of a marathon

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Major goals of reorganizing 318 Find and understand the information you need

quickly Increase certainty that a design fully meets the

Code

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Conceptual design of the code

Organized by what you are designing a structural system a slab or beam a column a wall a diaphragm etc.

Plus some additional topics required to design and construct a building

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The structural system and its loads (Ch. 4)

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Seismic systems (Ch. 18)

Slabs (Ch. 7, 8)

Walls (Ch. 11)

Columns (Ch. 10)

Foundations (Ch. 13)

Loads (Ch. 5)Analysis (Ch. 6)

Diaphragms (Ch. 12)

Beams (Ch. 9)

Part Chapter1.General 1.General

2.NotationandTerminology3.ReferencedStandards4.StructuralSystems

2.Analysis 5.LoadsandLoadCombinations6.StructuralAnalysis

3.Memberdesign 7.OneWaySlabs8.TwoWaySlabs9.Beams(includingDeepBeams)10.Columns11.Walls12.Diaphragms&Collectors13.Foundations14.PlainConcreteMembers

4.Joints,Connections,andAnchoringtoConcrete

15.BeamColumnandSlabColumnJoints16.ConnectionsBetweenMembers17.AnchoringtoConcrete

5.SeismicDesign 18.EarthquakeResistantStructures6.MaterialsandDurability 19.ConcretePropertiesandDurability

20.SteelReinforcementPropertiesandDurability7.StrengthandServiceability 21.StrengthReductionFactors

22.SectionalStrength23.StrutandTieMethod24.Serviceability

8.GeneralReinforcementDetails 25.ReinforcementDevelopment,Splices,andDetails9.Construction 26.ConstructionDocumentsandInspectionRequirements10.ExistingStructuresEvaluation 27.StrengthEvaluationofExistingStructures

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ACI 318-14 chapter organization

Example: Chapter 10 Columns10.1 Scope10.2 General10.3 Design Limits10.4 Required Strength10.5 Design Strength10.6 Reinforcement Limits10.7 Reinforcement Detailing

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1411


9.5.2

9.5.3

9.7.5

9.7.4

9.2.2

9.7.1

9.7.6.1

9.5.1


LapSplice,

Cover,

TiesinJoint,Slope,

Chapter10Chapter11

Chapter9

12.1512.177.8.1.1

11.10.2

7.7

7.10.5

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Ties,

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14


10.5.2

10.5.3

10.7.5

10.7.4

10.2.2

10.7.1

10.7.6.1

10.5.1


LapSplice,

Cover,

TiesinJoint,Slope,

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Ties,

ACI 318-Organization

Part Chapter1.General 1.General

2.NotationandTerminology3.ReferencedStandards4.StructuralSystems

2.Analysis 5.LoadsandLoadCombinations6.StructuralAnalysis

3.Memberdesign 7.OneWaySlabs8.TwoWaySlabs9.Beams(includingDeepBeams)10.Columns11.Walls12.Diaphragms&Collectors13.Foundations14.PlainConcreteMembers

4.Joints,Connections,andAnchoringtoConcrete

15.BeamColumnandSlabColumnJoints16.ConnectionsBetweenMembers17.AnchoringtoConcrete

5.SeismicDesign 18.EarthquakeResistantStructures6.MaterialsandDurability 19.ConcretePropertiesandDurability

20.SteelReinforcementPropertiesandDurability7.StrengthandServiceability 21.StrengthReductionFactors

22.SectionalStrength23.StrutandTieMethod24.Serviceability

8.GeneralReinforcementDetails 25.ReinforcementDevelopment,Splices,andDetails9.Construction 26.ConstructionDocumentsandInspectionRequirements10.ExistingStructuresEvaluation 27.StrengthEvaluationofExistingStructures

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ACI 318-14 Organization

Column Chapter

10.5 Design strength 10.5.1.1 Design strength shall satisfy (a) to (c)

(a) (b) (c) 10.5.2.1 and shall be calculated in accordance with 22.4.

10.5.3.1 shall be calculated in accordance with 22.5.

Sectional Strength Chapter

22.4 Axial strength or combined moment and axial strength

22.5 One-way shear strength

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21.9.9 Construction jointsAll construction joints in structural walls shall conform to 6.4 and contact surfaces shall be roughened as in 11.6.9.

6.4.3 Construction joints shall be so made and located as not to impair the strength of the structure. Provision shall be made for transfer of shear and other forces through construction joints. See 11.6.9.

11.6.9 When concrete is placed against previously hardened concrete, the interface for shear transfer shall be clean and free of laitance. If is assumed equal to 1.0, interface shall be roughened to a full amplitude of approximately 1/4 in.

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23.4.7 Joints in concrete23.4.7.1 Design information:(a) Locations and details of construction, isolation and contraction joints if required by the design

(b) Provisions required for transfer of shear and other forces through construction joints.

23.4.7.2 Compliance requirements:(a) Joint locations or joint details that differ from those indicated in construction documents shall be submitted for approval by the licensed design professional to ensure they do not impair the strength of the structure. .

In 318-11:

7.6.7.1 Center-to-center spacing of pretensioningtendons at each end of a member shall be not less than 4db for strands, or 5db for wire, except that if specified compressive strength of concrete at time of initial prestress, fci , is 4000 psi or more, minimum center-to-center spacing of strands shall be 1-3/4 in. for strands of 1/2 in. nominal diameter or smaller and 2 in. for strands of 0.6 in. nominal diameter. See also 3.3.2.

ACI 318-14 Style

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ACI 318-14 Style

Same requirements in a table

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Table 25.2.4 Minimum center-to-center spacing of pretensioned strands at ends of members

fci, psi

Nominal strand

diameterin.

Minimum s

< 4000 All 4db (a)

4000 0.5 in. 1-3/4 in. (b)0.6 in. 2 in. (c)

Chapter 10 - Columns10.1 Scope

10.1.1 Provisions of this chapter shall apply to the design of nonprestressed, prestressed, and composite columns. The provisions shall also apply to the design of reinforced concrete pedestals:

10.1.2 The provisions of Chapter 14 shall apply for the design of plain concrete pedestals.

SourceofthisprovisioninACI31811

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Chapter 10 - Columns10.2 General

10.2.1 Materials

10.2.1.1 Design properties for concrete shall conform to Chapter 19.

10.2.1.2 Design properties for steel reinforcement and structural steel used in composite columns shall conform to Chapter 20.

10.2.2 Composite columns.

10.2.3 Connection to other members

10.2.3.1 For cast-in-place construction, beam-column and slab-column joints shall satisfy the requirements of 15.2.

10.2.3.2 For precast construction, connections shall satisfy the force transfer requirements of 16.3.

10.2.3.3 Connections of columns to foundations shall satisfy the requirements of 16.4.

Chapter 10 - Columns10.3 Design limits10.3.1 Dimensional limits

.

10.3.1.3 For columns built monolithically with a concrete wall, the outer limits of the effective cross section of the column shall not be taken greater than 1.5 in. outside the transverse reinforcement.

10.3.1.4 For columns with two or more interlocking spirals, outer limits of the effective cross section shall be taken at a distance outside the spirals equal to the minimum required concrete cover.

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Chapter 10 - Columns

10.4 Required strength

10.4.1 General

10.4.1.1 Required strength shall be calculated in accordance with the factored load combinations defined in Chapter 5 and analysis procedures defined in Chapter 6.

10.4.2 Factored axial force and moment

10.4.2.1 Pu and Mu occurring simultaneously for each applicable factored load combination shall be considered.

Chapter 10 - Columns10.5 Design strength10.5.1 General

10.5.1.1 Design strength at all sections along the column shall satisfy Sn U, including (a) to (c), for each applicable factored load combination. Interaction between axial force and moment, as well as interactions between other load effects, shall be considered.

(a) Pn Pu(b) Mn Mu(c) Vn Vu

10.5.1.2 shall be determined in accordance with 21.2

10.5.2 Axial force and moment

10.5.2.1 Pn and Mn shall be calculated in accordance with 22.4.

10.5.2.2 For composite columns, forces shall be transferred between the steel section and concrete by direct bearing, shear connectors, or bond in accordance to the axial strength assigned to each component.

10.5.3 Shear

10.5.3.1 Vn shall be calculated in accordance with 22.5.

10.5.4 Torsion

10.5.4.1 If.

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Chapter 10 - Columns10.6 Reinforcement Limits10.6.1 Minimum and maximum longitudinal reinforcement

10.6.1.1 For noncomposite columns with average fpe < 225 psi, area of longitudinal reinforcement shall not be less than 0.01Agor more than 0.08 Ag.

10.6.1.2 For composite columns with a structural steel core, area of longitudinal bars located within the transverse reinforcement shall not be less than 0.01(Ag Asx) or more than 0.08(Ag Asx).

'0.75 wcyt

b sff

50 wyt

b sf

10.6.2.2 If shear reinforcement is required, Av,min shall be the greater of (a) and (b).

(a)

(b)

10.6.2 Minimum shear reinforcement

10.6.2.1 A minimum area of shear reinforcement, Av,min, shall be provided in all regions where .

Chapter 10 - Columns10.7 Reinforcement detailing10.7.1 General

10.7.1.1 Concrete cover for reinforcement shall be in accordance with 20.8.1.

10.7.1.2 Development lengths of deformed and prestressed reinforcement shall be calculated in accordance with 25.4.

10.7.1.3 Bundled bars shall be detailed in accordance with 25.6.

10.7.2 Reinforcement spacing

10.7.2.1 Minimum spacing s shall be in accordance with 25.2.

10.7.3 Longitudinal reinforcement

10.7.3.1 For columns with average fpe < 225 psi, the minimum number of longitudinal bars shall satisfy (a), (b), or (c):

(a) 3 within triangular ties;

(b) 4 within rectangular or circular ties;

(c) 6 enclosed by spirals or for columns of special moment frames enclosed by circular hoops.

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Chapter 10 - Columns10.7.4 Offset bent longitudinal reinforcement .10.7.5 Splices of longitudinal reinforcement.10.7.6 Transverse Reinforcement.

VsMaximums,in.

NonprestressedColumn

PrestressedColumn

Lesserof:24

Lesserof:12

'4 c wf b d 2d 3

4h

'4 c wf b d 4d 3

8h

10.7.6.5 Shear

10.7.6.5.1 If required, shear reinforcement shall be provided using ties, hoops, or spirals.

10.7.6.5.2 Maximum spacing of shear reinforcement shall be in accordance with Table 10.7.6.5.2.

Table 10.7.6.5.2 Maximum spacing of shear reinforcement

ACI 318-14 chapter organization

Example: Chapter 10 Columns10.1 Scope10.2 General10.3 Design Limits10.4 Required Strength10.5 Design Strength10.6 Reinforcement Limits10.7 Reinforcement Detailing

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Benefits of ACI 318-14

Organized from a designers perspective

Easier to find specific requirements

Intuitive location of information

Reduced cross references

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Benefits of ACI 318-14

Tables and mathematical expressions improve speed of understanding

Consistent language in text

Single idea for each requirement

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Schedule to Publication

Committee work ends summer 2013 Internal ACI review ends fall 2013 Public comment period spring 2014 Committee response summer 2014 Publication fall 2014

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Publication

ACI 318-14 will be published in: English Spanish

ACI 318-14 will be published in: US Customary units SI units

It will be available in an variety of formats, including: Printed copy Enhanced PDF EPUB, MOBI

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Additional Resources

Transition key maps: ACI 318-11 to ACI 318-14 ACI 318-14 to ACI 318-11

ACI Reinforced Concrete Design Manual (SP-17) will be consistent with 318-14

Online learning In-person seminars

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How To Get Involved:

Review 318-14 during public discussion period

Join the conversation on Twitter by using #ACI318 and #ConcreteCode

www.facebook.com/AmericanConcreteInstitute

www.concrete.org/ACI318 for more information (http://www.concrete.org/committees/pdf/tempdoc/documents/318-14/current318reorg.htm)

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Technical Changes in ACI 318-14

Diaphragms Columns of special moment frames Beam-column joints of special moment

frames Special structural walls

Diaphragms and Collectors (Chapter 12)diaphragm

transfer slab/diaphragm

inclinedcolumn

below grade soil pressure

in-planeinertial loads out-of-plane

wind pressure or inertial loads

shear transfer in diaphragm

collector

distributor

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Stiffness assumptions

wall

max

Lateralforce

Lateralforceresistingwallateachend

Anysetofreasonableandconsistentassumptionsarepermitted.(Mostdiaphragmscanbemodeledasrigidintheirplane.)

Diaphragm components (chords)

vu

Vu

(a)Plan

M

V

(b)SimplebeamidealizationMu

Vu

compressionchord

tensionchord

wall

diaphragm

(c)Internalmomentandshearresistance

MuCu

Tu

d

3.DiaphragmComponents

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Collectors (drags, struts)

(b)Collectoractions(a)Plan

a

b

c

d

collectorsamewidthaswall

beff

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collectorspreadintoslab

Cu,max

Tu,max

vua

b

c

d

3.DiaphragmComponents

Typical collector and shear-friction reinforcement detailing

Dowels

Collectorreinforcementdistributedtransverselyintothediaphragm Structuralwall

Coldjoint

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Special moment frames

Columns Beam-column joints

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Rotation, rad

Mom

ent,

k-in

.

0

10,000

20,000

30,000

'6.0 cg fAP '35.0 cg fAP

'1.0 cg fAP

Calculated moment-rotation relations for columns

Target

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Drift capacity of columns

0 0.5 1 1.5 2 2.50

1

2

3

4

5

6

7

8

9

10

, ,

Driftratio,% 0.20.2 0.4 0.4

Main changes to column provisions 350

0.3 70

200

0.3 70

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Main changes to column provisions

, 0.6 1.0

Transversereinforcement

Conditions Applicableexpressions

forrectilinear

hoop

Pu 0.3Agfc andfc 10,000psi

Greaterof(a)and(b) 0.3

1

a

0.09

b

0.2 c Pu >0.3Agfc orfc >10,000psi

Greaterof(a),(b),and(c)

Effect on amount of confinement

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

10 15 20 25 30 35 40 45 50

Ash2

014/

Ash2

011

columnwidth(in)

P/Agfc=0.3P/Agfc=0.4P/Agfc=0.5

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Beam-column joints in special moment frames

(a) (b)

Hooksmustbendintothejoint.

Headed reinforcement in joints

Minimumclearspacing3db

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(a)Elevation

(b)SectionAshowingverticalties

Knee joints with headed bars

ACI 318-14 Wall Design Provisions

Wall instability At least two curtains of reinforcement shall be

used in a wall if 0.17 (MPa) or 2, in which hw and lw refer to height and length of entire wall, respectively.

Width b of flexural compression zone shall satisfy 16 , where hu = unsupported height of wall.

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ACI 318-14 Wall Design Provisions Special boundary elements

Special boundary elements are required where . , in which shall not be taken less than 0.005.

For walls with 2 and 3 8 , wall thickness shall be at least 300 mm.

ldh orldt

150mmStraightorstandardbaroffset,anchoredldh orldt inconfinedcore

hoopsets@s minhx =spacingofhooportielegslesserof360mmand lbe max(c 0.1lw, c/2)

b

Hoops/crosstiesalsosatisfyrequirementsforlongitudinalbarrestraintand:

ACI 318-14 Wall Design Provisions Special boundary elements

b/36db longitudinal

100 355 75 mm150mm

0.09

0.3

1

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ACI 318-14 Wall Design Provisions Ordinary boundary elements having be > 2.8/fy MPa

Standardhooksengagingverticaledgereinforcement

hx =maxspacingofhooportielegs360mm)hoopsets@s lesserof200mmand8db (exceptslesserof150mmand6db atyieldingsection)

lbe max(c 0.1lw, c/2)

Hoops/crosstiesalsosatisfyrequirementsforlongitudinalbarsupport

ACI 318-14 Wall Design Provisions Wall detailing over height

criticalse

ction

max,4 ,

specialboundaryelement

ordinaryboundaryelement

for1.25

305mm

tiesnotrequired

boundaryelementnearedgeoffootingorothersupport

boundaryelementnotnearedgeoffooting

, , 2.8 MPa

(orhookasreqd.)

, , 2.8 MPa

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ACI 318-14 Chile 2 Slides Per Page

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