ACI 562-13 “Code” document is new – just a sleeping Pup

ACI 562 CODE

HOW DOES IT AFFECT YOUR CONCRETE REPAIR PROJECT?

PRESENTED BY GENE STEVENSJ. R. HARRIS & COMPANY

Slides Edited by: Gene Stevens – Chair ACI 562 SUB-A: Chap. 1 - 4, 9, & 10, and Appendices A & B

Written by & Previously Presented by: KEITH KESNER – CHAIR ACI 562LARRY KAHN – FORMER CHAIR ACI 562

Presentation Goals

• Background on Code Requirements for Evaluation, Repair and Rehabilitation of Concrete Buildings (ACI 562-13)

• Code development process

• How ACI 562 works – How it affects your project: Key provisions

Changes in concrete repair practice Engineering for Existing Concrete Buildings

ACI 562 – Key Points

• Developed to improve concrete repair practiceWhy this is necessary.

• Performance-based code – decisions focus on requirements of demand & performance

• Help design professionals and building officials Evaluation Criteria and Design-Basis Criteria in 2016 +

• Work in progress – 562 is growing & developingCommittee interested in feedbackWorking on ACI 562-16 for adoption into IEBC-18

Presentation Outline

• Introduction– Why a Repair Code– Repair Code Concerns

• Code Attributes*– Building Code Process– Codes vs. Guidelines– Code vs. Commentary

• ACI 562– Development– Revision of Existing Codes– Philosophy & Organization– Responsibilities– Changes in IBC / IEBC– Issues with IEBC

• Specifics of 562– When Applicable– Maintenance– Preliminary Evaluation– Evaluation– Analysis– Load Testing– Reinforcement– Durability– Construction

• Future of 562– Going Forward– Impact

Why a Repair Code?

• Vision 2020 – ACI Strategic Development Create a repair/rehabilitation code for Existing Concrete Buildings to:Establish evaluation, design, materials and construction practices{Develop Standard to provide engineering methods to make decisions}Raise level of repair/protection performanceEstablish clear responsibilitiesProvide Building Officials with means to issue permits

• Repairs are a large segment of construction industry20 Billion dollars {roughly 18 to 25 Billion per year}

8 Billion dollars per year in corrosion damage

Why a Repair Code:

• Repair performanceCOE - 50% of repairs are not performing satisfactorilyEngineering - Design or Evaluation errorsFaulty Repair Construction - Installation, Material selection, and Material performance

Conc. Repair Performance - Unsatisfactory5 years – 80% of repairs are satisfactory10 years – 30% of repairs are satisfactory 25 years – 10% of repairs are satisfactory

215 useable case-histories

• 50% Successful and exhibiting no signs of deterioration.• 25% Exhibiting evidence of deterioration, …not necessarily

requiring remedial action.• 25% Failure, clearly requiring remedial action.

Repair failure rates:Preformance of Concrete Repairs (Buildings, Parking and other

Concrete Structures)

80%

30%

10%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

0-5 Years 6-10 Years 11-25 Years

Age of Repairs

% S

till S

ucce

ssfu

l

Overall Average:

Variations in repair & engineering practice

Different levels of safety / reliability

No direction for building officials

Challenges of existing structures:Hidden damageUnknown structural conditions

Why a Repair Code? [10]

Lack of specific code requirements:

Complicated process– Giving birth to a CodeTook 7 years to develop and deliver

{needed about 12 yrs.}

Lack of consensus on practiceMany discussions and we are still debating issues

Repair Code Concerns?

1928 Parking Garage

Establish minimum practice requirements

What are minimum requirements?

Concern about limiting creative solutions

Fear of change

Repair Code Concerns?

1928 Parking Garage

Motivation:Survey of ACI 318 users

1/2 of those surveyed use ACI 318 for repair of existing structures

also use 318 for non-building structuresConclusion from ACI 318 Survey

ACI 318 is functioning beyond its intentguidance requiredto save $$$for repairs needed

Stop repairing repairs

Building Codes• Developed by consensus process (Public review

and ANSI approved)Written by code writing organization

Code committee - Membership balance Producers / Users / General Interest

Written for design professionals: Architects and engineers – License Design Professionals

• When adopted codes become lawGeneral building code (IBC) and Existing-building code (IEBC) are legal requirementsFeeder building codes – ACI 318 & ACI 562

Code vs. Commentary vs. Guidelines*• Code

Adopted by regulatory agenciesMandatory language (shall not should)Establish required practice

• Commentary – usually written by code committeeNon-mandatory language (should not shall)Guidance on how to satisfy code

• GuidelinesNon-mandatory language (should not shall)Establish recommended practice

Code vs. Standard

• In Colorado – a code is legally adopted by a local jurisdictional authority – about 246

• Standards that are not adopted and are not law.• Bylaws and Rules for PE in Colorado: 3.1.4 - Work Product must be Safe and meet

Generally Accepted Standards Eng. Responsibilities include: Standards to

use and methods used in evaluation of completed work

How was ACI 562 Developed?*• Committee formed in Spring 2006• ACI code committee – “Evaluation, Repair and

Rehabilitation of Concrete Buildings”• Starting points

Existing U.S. building codesExisting international repair codes

Philosophy of code

1928 Parking Garage

Wire mesh safety net for potential failing hazards

U.S. CodesACI 318, Chapter 20IBC, Chapter 34

5% rule [increase in demand or decrease in capacity] trigger for upgrade to current code

Repair requirements vary

IEBC First published in 2003

562 developed for adoption into IEBC

Starting point - Review of Existing Codes*

1928 Parking Garage

IEBC does not address many issues:1. Basic deterioration (aging) of concrete & repair

– with and without strengthening2. Criteria used to evaluate deteriorated or

distressed structures3. Faulty construction:Criteria to evaluate: safety & occupancy loadsRehabilitation & reporting

4. Damage less than substantial structural damage5. Unsafe conditions – potentially dangerousDoes ACI 562 needs to be adopted? – Yes & No

ACI 562 – Philosophy• Emphasize performance based rather than

prescriptive requirements where decisions focus on requirements of demand & performance

• Encourage creativity and flexibility• Promote innovation and new materials• Establish responsibilities• Enhance life safety (equivalent safety)• Extend service life• Provide sustainable and economic alternatives• Use ACI and other “code” documents by reference

Responsibilities: [21]

• Licensed Design Professional Evaluate and Repair using durable designs

• Constructor use plans and specificationsFollow engineering specifications, report uncovered defects, construction sequencing, means & methods

• Owner – through general building codeAddress known conditions and maintenance

Whalers Village – Malibu, CA

Design Basis Code for 562Original building code under which the repair project is completedPossible design basis codes:

IBC, IEBC, Local building code, i.e., LA or NYC Building Code, ACI 318, Combination of ACI 318 and 562

Whalers Village – Malibu, CA

Grade Beam

Slab-on-grade

Ero

sion

When do structures need to satisfy current codes?IBC – Chapter 34: 1. If alterations or additions increase force in a structural element by more than 5% or 2. Repairs to elements that are found to be “unsound or structurally deficient” - What does that mean? ACI 562-13 is not completely clearWith limits, ACI 562-16: demand greater than capacity, 𝑈𝑈 > 1.1∅𝑅𝑅𝑛𝑛

IEBC - When “substantial structural damage” has occurredWhen required by a local codeor building official

External PT

What about deteriorationand faulty construction?

Changes in IBC and IEBC

for 2015 IBC Code ICC Board approves deletion of Chapter 34 of the IBC in favor of reference requiring the IEBC

2015 IBC Will no longer include Chap. 34, Existing Structures IEBC currently adopted for use in 47 states and in 56% of the jurisdictions in Colorado.If IBC then IEBC

Whalers Village – Malibu, CA

Twice daily salt water wash

ACI 562-13 & 16 with or without IEBC:

- Assume: Concrete Deterioration in Vail, CO of parking garage top deck (D = 90 psf) - IBC & IEBC 2015 is adopted

- IEBC 404.4 – less than substantial structural damage?- Original Code is UBC 1967 (local snow 75 psf) and ACI 318-63, which does not include snow loads – 50 psf used for garage: Uo= 1.5D+1.8L= 225 psf to 270 psf- Structural capacity including φ is 225 psf. Per ACI 562-13, building complies with ACI 318-63 and is safe. – Is it?- Say we ignore ACI 562 and use IEBC and assume deterioration is basically damage – Per 404.4 repairs allowed that restore the building to predamage state.

ACI 562-13 & 16 with or without IEBC: Cont.

Using proposed ACI 562-16: Check current building code, ground snow of 145 psf:S = 112.5 psf, which may or may not applyUc = 1.2D+1.6S+L = 338 psf > 225 psf = Uo = φRcn

- UNSAFE? Insufficient structural reliability w/o snowplowing using IEBC 2015

- [ �𝑼𝑼𝒄𝒄∅𝑹𝑹𝒄𝒄𝒄𝒄 > 𝟏𝟏.𝟓𝟓 ] – Proposed ACI 562-16,

Appendix A, Sect. A.3

Does ACI 562-16 need to be Adopted?

1. If IEBC 2015 is or is not adopted & ACI 562-16 is not adopted, repairs would have insufficient structural reliability [225 psf or 270 psf from the original building code] – per IEBC Sect. 404.4 restoring of the original capacity is compliant

2. If IEBC does adopt ACI 562-16 repairs would have adequate structural reliability [338 psf] used in repair design

3. Same as 2. if ACI 562-16 is locally adopted.

ACI 562 Specifics - ApplicabilityUse 562 for existing concrete buildingsSuperstructure [foundations (slabs), precast elements]

Nonstructural only for “Unsafe” componentsComposite members non-building structures

Whalers Village – Malibu, CARepair using carbon fiberStainless Steel Beam SeatFiberglass Beams

562 Specifics - Preliminary EvaluationDetermine extent of structural damage present

proposed 562-16 includes deterioration & faulty construction

Evaluation based upon current in-place conditionsAssumed material propertiesAssume a design basis code

proposed 562-16 includes evaluation criteria to establish a design-basis criteria for rehabilitation

Check for Unsafe or Substantial structural damage?Required compliance with current code

IEBC: Substantial Structural DamageIEBC {open to interpretation} – my translation is

1) Capacity reduction of more than 33% for vertical elements of the lateral-force-resisting system or

2) Capacity reduction of more than 20% for vertical elements of gravity load resisting system in an area that supports more then 30% of the structures area

May trigger upgrade of structure or member repairs using current code requirements

562 Specifics - Evaluation & Analysis• Preliminary evaluation• Investigate when there is reason to question

performance or safety – such as damage, deterioration, etc.

• Structural analysis• As-measured section properties and dimensions• Material properties use: Available documents and/or historical tables Tests

• Structural assessment

Assessment vs. Evaluation – Terminology#

• Proposed 562-16 defines assessment & evaluation• Assessment is an evaluation with conclusions &

recommendations for the future• Evaluation is the process of determining and judging

the structural adequacy of members or systems for the intended use or performance objective

Proposed 562-16: “Code Regulations for Assessment, Repair, and Rehabilitation of Existing Concrete Structures”

562 Specifics - Evaluation & Analysis – Testing [30]

Destructive & nondestructive [NDT] - [Sect. 6.4]Cores (ASTM C42 & C823) - [Sect. 6.4.3]NDT when valid correlation is established [Sect. 6.4.3.1]

Steel Reinforcement: historical values, samples (ASTM A370) - [Sect. 6.4.4 - 6.4.10]

Whalers Village – Malibu, CACore Sample from Concrete Drilled Pier

562 Specifics: Loads and Resistance FactorsCapacity reduction factor, Φ [Sect. 5.3 & 5.4]

Measured properties [Sect. 6.3]Failure modeHistoric material properties [Table 6.3.1]

Load Factors – Default values ASCE 7 [Sect. 5.2]

Whalers Village – Malibu, CARepairs using carbon fiberFor beams and drilled piers

562 Specifics: Loads and Load CombinationsEssentially ASCE/SEI 7 (ACI 318) [Sect. 5.1.6]

Construction ASCE/SEI 37 [Sect. 5.1.4]

External reinforcing systems [Sect. 5.5]

Uex = 1.2D + 0.5L + Ak + 0.2S {ASCE 7-10, Sect. 2.5}

Fire + elevated temp.with FRP or external unprotected reinforcement

External PTDenver, CO

562 Specifics: Φ factorsEncourage confirmation of material propertiesΦ factors from ACI-318 for New Design

If, no confirmation of material propertiesACI 318 Chapter 20 if material properties are confirmed

Φtension= 1.0 Φcompression= 0.9 Φshear= 0.8

External PTCorbel at columnUsed ACI 562-13

562 Specifics: Typical Repair Project1. Preliminary evaluation -

a) Are unsafe conditions present? – [ACI 562-16]b) Is substantial structural damage present? [Sect. 4.3.3]

IEBC & ACI 562 triggers for upgrade to current code requirementsEstablish design basis code

2. Must considerImpact of damage (deterioration & distress) present

In-place geometry and material properties

562 Specifics: Typical Repair Project• Structural evaluation [Sect. 6.1]

Structural review, structural analysis or both• How bad is the structure?

Whalers Village – Malibu, CA 1928 Parking Garage

562 Specifics: Typical Repair ProjectStructural analysis – required when?

Preliminary evaluation resultsReason to question performanceInsufficient information

Similar elements?Consider if additional elements requireevaluation and repair

Whalers Village – Malibu, CARepairs using carbon fiberFor beams and drilled piers

562 Specifics: Critical Code Sections [6.1]“If the strength of a structure is known, improvements to the strength, serviceability, durability, and fire performance of a structure shall be permitted without performing a structural evaluation.”How do you know the strength of a structure?

Voluntary improvements can be madeIntent is tosimplifyprocedures

1970’s PT Parking Garage – fractured strand

562 Specifics: Critical Code Sections [6.1]“If determined by the structural assessment (judgment)that the strength of a structure is not in question,structural analysis is notrequired.”

Performance criteriaResponsibility of LDPto determine

1970’s PT Parking Garage

562 Specifics: Critical Code Sections [6.1]“Where repairs are required on an element in astructure, it shall be determined if similar elementsthroughout the structure alsorequire evaluation.”

Repetitive elementsIsolated repairs maynot be acceptable

Whalers Village – Malibu, CAdocumented distress inbottom of grade beam

562 Specifics: Unknown Structural Capacity [41]

• Lack of design drawingsDetermine geometryDetermine loads

• In-situ conditionsACI 201ACI 228.1ACI 364ACI 437ASCE Guidelines

1970’s PT Parking Garage – Documentation

562 Specifics: Unknown Structural Capacity

• Unknown material propertiesHistorical valuesPhysical testing

• # of samples?• # of elements?• NDT – with correlation

Sect. 6.4 – Tests to confirm properties

Whalers Village – Malibu, CADrilled Pier, Concrete Core

562 Specifics: Analysis, Design and Durability

• Analysis - Performance based – 3D, nonlinear or…[Sect. 6.5]

Make a patch or add a structural wall• Actual load and force distribution [Sect. 6.5.4]• Reinforcement and repair materials [Sect. 7.5.1]

e.g. FRP’s and polymer concretes• Compatibility [Sect. 7.3.2]• Fire resistance [Sect. 7.9]• Service life [Sect. 8.1.2]

562 Specifics: Seismic Resistance• ASCE/SEI 31 – Seismic Evaluation • ASCE/SEI 41 – Seismic Rehabilitation [1.1.8 & 7.6.4]• ASCE/SEI Guidelines used in IBC and IEBC• ASCE/SEI 41-13 – in Proposed ACI 562-16

562 Specifics: Load Testing• ACI 437-13 [Sect. 6.8] - New code for load testing• Why not ACI 318-11 Chapter 20? - archaic

deflection limits – use for buildings under construction

Not 1928 Parking Garage, but they did sit there for 24 hrs. to comply with Chap. 20’s deflection requirement

562 Specifics: Load Testing*

• Load testing (ACI 437-13) [Sect. 6.8]More rational for existing structuresLower DLShorter holdService load evaluation

• Model testingSupplement analysis

562 Specifics: Design of Structural Repairs

• Strength & Serviceability [Sect. 7.1, 7.2]• Effect of repair on structural system [Sect. 7.3]• Composite behavior

Tensile strength Adhesives Pull-off test

Bond:conservatively,1.5 x required [Sect. 7.4]

1970’s PT Parking Garage – Bond Capacity

562 Specifics: Repair Design

Bond {revisions in 2016} [Sect. 7.4]Critical to performance of a repairBond strength greater than 1.5 times the required bond capacity demandTensile strength of concrete

Tensile Strength:Testing – ASTM C 1583

4 𝑓𝑓𝑐𝑐′ in lieu of testingSupplemental Reinforcement

562 Specifics: ReinforcementFRP [7.8] & (ACI 440.6) and steel Fire [7.9] (external reinforcement)

Uex = 1.2D + 0.5L + Ak + 0.2S (Eq. 5.5.1)Existing prestressingSupplemental post-tensioning[Sect. 7.7]

Secondary effectsDefine repair sequenceremoval, placement, & stressing

Whalers Village – Malibu, CACarbon Fiber Reinforcement

562 Specifics: Durability [50]

• Durable materials [Sect. 8.1.1 & 8.1.2]Interaction with existing structure (compatibility)In environment Anticipated maintenance

• Corrosion protection & cover [Sect. 8.2]

Whalers Village – Malibu, CA 1928 Parking Garage – corrosion protection

562 Specifics: DurabilityCorrosion & deterioration of [Sect. 8.4] reinforcement: Corrosive environment, Existing reinforcement & Galvanic actionCracks [Sect. 8.3]

1928 Parking Garage – top reinforcement

562 Specifics: Construction• Stability and temporary shoring [Sect. 9.1]

Designed by an LDPConsider: sequence, in-situ conditions, changes in conditions

1928 Parking Garage – depth of slab during repairs

562 Specifics: Construction

Temporary conditions [Sect. 9.2]

ASCE/SEI 37 when feasibleStalled projects?

Environmental [Sect. 9.3]

Instructions to contractor• Report new conditions• Control of debris

Shoring for Vail Ritz Carlton Designed by JRH for PCL

Controversy – Maintenance* To assure durable repairsTo protect design professionals“Maintenance recommendations shall be documented…” [Sect. 1.5.2 & 1.7]“A maintenance protocol should be provided…” [Sect. 1.7C]ACI 562 does not want to address Maintenance

Gates Water Tank

People

562 Specifics: Typical Repair ProjectQuality Assurance Plan [Sect. 10.1]

Required by current building codeContract documents – don’t conceal until inspected

Maintenance Plan [Sect. 1.5.2 and 1.7]Document specific requirements for ownerProtect design professional

External PT 1970’s PT Parking Garage – Bond

562 Specifics: Quality AssuranceRequire testing and inspection [Sect. 10.1]

Commentary list of items to inspect [Sect. 10.1.2C]Repair inspectors should be qualified by demonstrating competence

LDP may inspect their projectsTesting as required by LDP [Sect. 10.2]

Existing conditions shall not be concealed [Sect. 10.1.3]

Construction observation [Sect. 10.3]

External PTsurvey during tensioning

Summary of ACI 562Performance-based code for existing concrete structuresGoal - to improve repair practice – Code/standard

Increasing flexibility & creativityaccommodating new materials

Help design professionalsRational basis for repair permits [help building officials]

Growing & ImprovingBut still a Pup

ACI 562 - Going Forward Improve the state of practiceIncorporate work of other committees / groups

Repository of knowledgeACI Guidelines: ACI 563 Specs. for conc. repairICRI Documents

Education on ACI 562ACI / ICRI Guide to 562SeminarsPresentations

Big Dog Future

Impact of ACI 562

• Cost savings for repair of repair in $ billions• Code requires accountability of both engineers

and contractors • Repair industry is a serious endeavor

Education and skills required• Engineering requirements leading to clear

specifications and increased quality• Safer structures

20% of $20 B = $4 B per year

Improved safety

ACI 562 - Coming Attractions:1. ACI 563 Specifications for Concrete Repair2. ACI 562-16 – significant changes in chapter 1-43. ACI Concrete repair inspection certifications – 20154. Guide to the ACI 562-13 Code by WJE – 20165. Proposed SEAC seminar on ACI 562-16, ACI 563,

Guide by WJE, and repair inspection certification program

6. Monthly ACI 562 Articles in Concrete International7. More Articles in Structures Magazine of NCSEA

Evaluation of Faulty Concrete Members, Systems & Buildings*

1. Noncompliance with contract agreement –design and construction considered separate

2. Damages ($) based on structural deficiencies require proof (no speculation) using: Measured geometries – conc. & bars Tests of concrete (cores) and reinforcement ACI 562-13, Section 5.4 for strength-

reduction factors Original code provisions not to exceed

current code – ACI 562-16