Rejuvenating Aging Port Infrastructure

gurglejapaneseΔιαχείριση

18 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

66 εμφανίσεις

Rejuvenating Aging Port Infrastructure

ADVANCED PREDICTIVE MODELLING



PROACTIVE APPROACH TO ASSET MANAGEMENT

PROJECTS

(supported by
Australian Research Council (ARC) LP0883290 and LP0776702, and Monash
internal
research grants
)
Contact: Dr
Frank Collins,
Department
of Civil Engineering

3D MODELLING OF DAMAGE DUE TO STEEL
REINFORCEMENT CORROSION

Australia’s

port

infrastructure

facilitates

$
213

(billion)

per

annum

in

total

trade
.

Port

infrastructure

is

primarily

constructed

of

reinforced

concrete

(RC)

and

is

exposed

to

a

corrosive

marine

environment
.

However,

maritime

infrastructure

is

vulnerable

to

deterioration

due

to

the

corrosive

influence

of

salt
-
laden

waves

and

sea

air
.

Deterioration

leads

to

loss

of

functionality,

delays

in

shipping

caused

by

maintenance

and

remediation

works,

and

in

the

worst

cases,

loss

of

structural

integrity

(leading

to

risks

of

injury

to

workers,

reduced

operation

of

the

facility

and

consequent

asset

replacement
.

Monash

University

has

been

actively

contributing

towards

sustaining

aging

built

port

infrastructure

by

conducting

research

on

predictive

modelling

of

deterioration

and

methods

of

controlling

corrosion
.


Corrosion damage beneath a major
port structure, resulting in detachment
of the surface concrete and losses of
steel

Existing

predictive

models

are

based

on

1
D

or

2
D

applications
.

Howe
ver

these

models

are

limited

due

to

non
-
consideration

of

3

dimension
al


aspects,

such

as
:

materials,

the

geometry

and

location

of

embedded


Reinforcing

steel,

and

the

aspect

and

location

of

the

exposed

concret
e


to

the

external

environment
.

The

key

predictive

modelling

aspects


include

“Time

to

corrosion

initiation”

based

on

diffusion

theory,

followe
d

by

incorporation

of

the

“Propagation

Stage”

and

the

“Time

to

dama
ge”


Including

crack

propagation,

loss

of

steel

to

concrete

bond,

loss

of

st
eel

section),

and

structural

capacity
.

Expansive

corrosion

of

embedded

steel

reinforcement

has

led

to

a

major

longitudinal

crack

along

t h e

s o f f i t

of

a

crosshead

beam

Swanson Dock, Australia’s Largest Container Terminal

The splash zone exposure environment is a
particularly corrosive microclimate underneath
a port structure

Cooperation with major Australian ports has lead to access of
historical condition data for analysis.
A user
-
friendly, real
-
time, 3D
deterioration model is being developed that will enable an asset
manager with appropriate knowledge and experience to use.

A 3D
visual aspect to the prediction tool will be a key model output. This
will allow both technical and non
-
technical users to review and
optimise the ongoing maintenance of the asset. Once the “base
-
line” geometry of a port structure geometry has been established,
the 3D prediction tool will be utilised to forecast the growth of
deterioration of the structure and developed into a prediction
animation that graphically demonstrates the future condition over
the remaining service life of the asset, allowing asset managers to
review and optimise the ongoing maintenance.

Corrosion Damage

3
D

Damage

Simulation

by

Finite

Element

Modelling

Within

most

structures,

concrete

normally

has

a

high

pH

(≈

12
.
5
)

due

to

hydration

of

the

cement

constituents

during

concrete

mixing
.

The

high

pH

is

conducive

to

the

embedded

steel

forming

a

passive

oxide

film

which

minimizes

corrosion
.

In

a

marine

environment,

chlorides

from

seawater

and

airborne

spray

accumulate

on

the

concrete

surface

and,

over

time,

diffuse

into

the

concrete
.

When

the

concentration

of

chloride

at

the

steel

depth

exceeds

a

threshold

concentration,

the

passive

oxide

film

converts

into

other

oxides

that

occupy

a

significantly

greater

volume

than

the

parent

steel
:

the

resulting

expansion

leads

to

tensile

stresses

within

the

outer

cover

zone

of

concrete,

leading

to

crack

and

detachment

of

the

concrete
.

In

the

worst

cases,

the

detachment

of

concrete

and

losses

of

steel

area

caused

by

corrosion

can

reduce

the

structural

capacity

of

the

structural

member
.

pH ≈ 12.5

Thin
passive iron
oxide layer forms
on the steel