lecture 1 retrofit

7/24/2019 Lecture 1 Retrofit

1/9

CONDITION ASSESSMENTAND RETROFITTING OF

STRUCTURES(CE-647)

Lecture-1


2/9

Proposed Syllabus:

1. Deterioration

of

concrete

buildings,

embedded

metal

corrosion,

disintegration mechanisms, moisture effects,

thermal effects,structural

effects,

faulty

construction

.

2. Evaluation

of

concrete

buildings,

visual

investigation,

destructivetesting systems, non

-

destructive testing techniques, semi

-destructive

testing

techniques,

chemical

testing

.

3. Structural health monitoring, vibration based monitoring

technique,

smart

materials

and

sensors

.

4. Surface repair and retrofitting techniques, strategy &

design,selection

of

repair

materials,

surface

preparation,

bonding

repairmaterials

to

existing

concrete,

placement

methods

.

5. Strengthening

techniques,

strengthening

techniques,

beam

shearcapacity strengthening, shear transfer strengthening

betweenmembers, column strengthening, flexural

strengthening, andcrack

stabilization

.

6. Seismic

rehabilitation

of

existing

buildings,

seismic

vulnerability

and

strategies

for

seismic

retrofit

.


3/9

Reference Material

Emmons, P.H., Concrete Repair and Maintenance Illustrated,Galgotia Publications Pvt. Ltd., New Delhi.

Bungey, S, Lillard, G. and Grantham M.G., Testing of Concrete inStructures, 4th Edition, Taylor and Francis, London.

Malhotra, V.M. and Carino, N.J., Handbook on Non-destructivetesting of concrete, 2nd Edition, Taylor and Francis.

Bohni, H., Corrosion in Concrete Structures, Taylor and Francis.

Handbook on Repair and Rehabilitation of RCC Buildings, CPWD,New Delhi.

Concrete Repair Guide, ACI 546R-04, ACI Practice Manual. Gangarao, HVS, Taly, N. and Vijay, PV, Reinforced Concrete Design

with FRP composites CRC Press, Taylor and Francis Group.

Grantham, MG, Concrete Repair: A Practical Guide, Spon Press.


4/9

INTRODUCTION


5/9

Definitions

1. REPAIR: It is the operation in which damage due to deterioration and

cracking is corrected to restore the original structural shape. The

repair does not change the structural function.

2. RETROFITTING/REHABILITATION/STABILIZATION/STRENGHENING

:The operation, which is necessary to strengthen the

structuralcapacity of members whose load carrying capacity

is eitherinadequate or

whose strength has

been severely

impaired due

tosustained

damage

.

It

includes

the

process

of

modifying

a

structure

to

a

desired

useful

condition

.


6/9

Introduction

Effect

LeakageDefect

Damage

Deterioration

Design

Materials

ConstructionSettlement

Deflection

Wear

Spalling

Disintegration

Cracking

Delamination

Scaling

Cause

Overloading

Chemical Spill

Earthquake

Fire

Freeze-Thaw

Erosion

Corrosion of

Metals

Alkali-Aggregate

Reaction

Sulfate Attack

Concrete does not always

behave as we would like;

some of the undesirable

behaviour can be seen as

disintegration, spalling,

cracking, leakage, wear,

deflection or settlement.

Developing effective repair

strategies requires an

understanding of what

caused the undesirablebehaviour.


7/9

An Overview of Present Repair Practices

The gap between the quality planned and quality achieved isbecomingwider.

The factors contributing to distress in buildings have becomeintrinsicrightfromtheconstructionstage.

Constructioninstructionsandspecificationsareoverlooked.

Standardcubetestresultsaretakenasthemeasureofquality?

The procedures for periodic inspection, maintenance ofbuildings/structures anddocuments for defects are not followedandmaintained.

LessexperiencedEngineersinthisarea. Sights of water stagnation, peeling of paints, plaster-break off,

fungusgrowth,cracksetc.arecommon.

Repairscarriedoutnormallywithoutunderstandingthecause-effectphenomenon.


8/9

Distress-Identification

Before attempting any repair procedure is necessary to have aplanned approach to investigate the condition of concrete andreinforcement.

Athoroughunderstandingofthebehaviourofstructuralcomponenttoberepairedisnecessary.

Atechnical inspection,mappingofdistressed/damagedareasanddocumentationoftypeandlocationofsymptomsarerequired.

A comprehensive inspection data helps in making an effectivestrategyforrepairandrehabilitation.

NonDestructiveEvaluationmayalsoberequired.

A certain level ofexperienceandunderstanding of limitations ofvariousmethodsofNonDestructiveEvaluationisrequired.


9/9

Repair Management

ThreestagesofRepairmanagement. Firststageinvolvesdocumentationofdamage,itstypeandextent,

prognosis of repaired structure and recommendations on repairmethodology.

The second stage involves preparation of detailed drawings,

execution guidelines, material andworkspecificationsandtenderdocument.

Thirdstageisactualexecutionofrepairs.

Supervising Engineer should have a good understanding of thesubject.

Selection of appropriate material and methodology of repair isimportant.

Theowners,engineers,materialsuppliersandcontractorsallneedtounderstandthebasicsofeachdisciplinerepresentedintherepairprocess.

lecture 1 retrofit

Documents