Structural Assets Newsletter #21, April 2007 [pdf, 249 KB] - Hatch

April 2007 Number 21
Structural Assets
GROUP LEADER’S INTRODUCTION
LIFE EXTENSION FOR
BUCKETWHEEL RECLAIMER
This is our twenty-first newsletter for Structural
Assets and the first edition for 2007. It is amazing
to see how the time has flown over the past two
years since our last newsletter. There is always so
much to do, with so little time left to do the things that we
would like to do. It has been a couple of extremely busy
years for our business, propelled by the global natural
resources boom. This trend has not shown any decline
and is currently looking positive for global business.
The Structural Assets Group continues to provide
services in the areas of:
Condition assessment, life extension and third party
independent design auditing of materials handling
machines (Stacker Reclaimers, Stackers,
Reclaimers, Shiploaders and Shipunloaders);
Condition assessment and life extension of industrial
structures such as bins, ducts, silos, bunkers, stacks,
tipplers, overhead cranes, thickener tanks and
agitator tanks; and,
Risk studies, specialist engineering advise and design
solutions.
The objective of this newsletter is to share engineering
knowledge gained during the course of our work with our
customers and colleagues. We would be pleased to
receive any comments or suggestions regarding this
newsletter from readers by e-mail or facsimile.
On behalf of the Structural Assets Group in Australia, I
would like to take this opportunity to extend greetings for
the upcoming Easter festivities to all of our clients, staff
and their families.
“We are what we repeatedly do. Excellence, then, is
not an act but a habit.” — Aristotle
Dr. S. Loganathan (Logan)
Lloganathan@hatch.com.au
A Happy and Safe
Easter to All
The bucketwheel reclaimer at a coal terminal was
commissioned in 1977 and de-commissioned in 2002,
when it was decided that due to the extent of major
structural defects, for example, structural cracking in the
luffing pivot, severe corrosion to bucketwheel region of
the boom, and high risk for further operation, the design
service life had been expended. At the time it was not
considered cost effective to affect the extent of repairs
necessary to allow it to continue in service with a
satisfactory level of risk.
General View of Bucketwheel Reclaimer
In 2004, due to the worldwide increase in the demand for
coal and the desire to increase throughput at the
terminal, due to an ever-increasing shipping queue, two
options were considered. Option one was to purchase a
new bucketwheel reclaimer of the same size at an
approximate cost of A$18M with a minimum lead time of
two years, or, option two, return the reclaimer back to
service. This would require the following major works:
Structural cracking in rocker arm assembly to be
repaired;
Hydraulic luffing cylinders to be removed, refurbished
and re-installed;
Slewing bearing to be replaced;
Bucketwheel, including shaft and drive assembly, to
be replaced; and,
Replacement of heavily corroded structural members
in bucketwheel boom.
Successful completion of the above would result in the
extension of the service life of the machine by 25 years.
The normal approach to the above tasks would be to
dismantle the machine in the reverse order to that in
which it was constructed. This would necessitate an
extensive laydown area adjacent to the machine
runway, the extended use of high capacity cranage and
involve considerable construction risk.

2 Structural Assets
In close consultation with the construction contractor a
solution was developed whereby the superstructure of
the reclaimer could be lifted in situ, with the boom and
counterweight still assembled, to allow the change out
of the slew bearing and the repair of the rocker
assembly.
Many issues referred to the Brisbane design office from
the construction site required detailed analysis and a
design solution to be undertaken and developed within
48 hours in order to meet construction milestones.
The project was completed successfully and the
machine has been in full operation since August 2005.
The owners have expressed their appreciation of
Hatch's engineering solutions and the value created for
their business.
For further information contact Dr S.Loganathan
(Logan) at Llogananathan@hatch.com.au
Faarms REBORN
Machine Jacked Up for Rocker Assembly Repair
Implementation required the design and fabrication of a
purpose built support frame, and other high load
capacity temporary works, which incorporated a
number of safety features such as strain gauges to
allow the monitoring of loads during the construction
process. This load measurement capability also
allowed constant monitoring of the machine balance
and was used to assist in the calculation of the mass of
counter weights necessary to maintain stability during
the construction phases when the major components
were jacked apart to facilitate replacement and repair
operations.
The final EPCM cost of the project wasA$6M with a total
project duration of twelve months from concept to end of
re-commissioning. This provided the client with an
immediate cost saving of A$12M, and gave further
value by providing an additional throughput of 2500
tonnes per hour. A minimum of twelve months prior to
that which would have been possible had option one
been adopted.
Von Mises Stress Plot of Rocker Arm Boss
To carry out the design works it was necessary for the
Structural Assets group to maintain an extremely close
working relationship with the owner and the
construction contractor in order to complete the
construction phase of the project in the six months.
PDG - Structural Assets Group
FAARMS
Facilities And Assets Risk Management System
LIFE EXTENSION - RISK REDUCTION - DESIGN SOLUTIONS
Version 5 - 2007
A new version of FAARMS has been developed by
Hatch to improve auditing efficiencies for clients. The
upgrade to version 5 of the system began in September
2005 by Hatch programmers, and was delivered to the
Wollongong office for testing in February 2006. After a
number of months of testing and using it on projects, the
system is ready for roll out to other offices in Australia,
starting with the Brisbane, Mackay and Townsville
offices that have existing auditing programs.
The new version has been upgraded from a file based
database (Microsoft Access) system to a client-server
SQL database system with a new user interface to
improve data entry. The use of the SQL database
server allows for additional system stability and
document storage over the old file based database.
The multi-user interface allows Hatch to enter more
information at one time and assists in centralising client
information to fewer locations improving data security
and integrity. The data can also be augmented with
photos, reports and supporting documentation server
location for easy access.
New licensing provisions will make it possible for clients
to have read only access to the information. This will
assist clients who use the information for forward
planning of works by allowing them to manipulate the
information to their own needs while not being
burdened with inefficient soft copies of spreadsheets
currently provided.
A new user interface has been developed to aid in data
entry and to provide more flexibility. Multiple clients
(users) can be individually set up in the one database to
suit each client's requirements.
The new entry set up also improves efficiencies in
information entry and reduces time required for report
preparation.

3 Structural Assets
Coupled with the new user interface is a reporting
module with improved flexibility in report formatting to
suit any requirements from multiple clients. All of the
existing report formats can be maintained for existing
clients and additional formats developed by any user as
required.
While testing is complete and further improvements
have been identified the system is available for release
to other Hatch offices. In the shor-term, improvements
will be added to the system in the next three months with
other long-term improvements being developed for
inclusion in late 2007.
Short-term improvements build on the main upgrade
and correct minor deficiencies in the user interface
encountered during testing.
Long-term improvements include the use of PDA
(Windows Mobile Devices) entry of information in the
field, comment generators to standardise condition
description entries and multiple language interfaces.
While the use of PDAs for entry on site will increase site
time the savings in report output will be much greater,
improving report turn-around, audit efficiencies and
reducing costs. Using comment generators for
condition descriptions will standardise the report and
provide more uniformity across audit teams and offices,
providing clients with greater confidence in the use of
different audit teams. Multiple language (French,
Spanish and Portuguese) interfaces will also help
Hatch take the system internationally to all offices
providing clients with a larger network of auditing
resources.
These long-term projects will be developed throughout
2007 and will be included in the system as they become
available.
The new version of FAARMS represents a large
investment by Hatch and brings the system up to
current technologies and client requirements. It is the
first step in taking the old system to greater heights
through more efficiencies and lower auditing costs and
shows Hatch's commitment to maintaining best
practices for our clients.
For further information contact Glenn Avery at
gavery@hatch.com.au
corrosive environment, the ducts structural integrity had
been compromised. Loss of plate thickness,
particularly at bends had occurred unobserved due to
the ducts being insulated and over sheeted to protect
the insulation.
Hatch Structural Assets Group was initially engaged to
assess the structural integrity of the ducts in their
existing condition. In order to carry out this assessment
of the structure the actual profile of the buckled duct and
the temperature distribution of the ducts was required.
The geometric profile was obtained from a 3D laser
survey carried out by AAMHatch. This survey produced
numerous co-ordinate points on the duct shell, referred
as 'point clouds', from which surface profile was
derived.
Laser Surface Profile
The shell temperature distribution was derived by
carrying out a surface thermographic survey. Based on
this information, a three dimensional model was
generated in MSC.FEA finite element analysis
software. The relevant design loads were applied to
calculate the stress in the ducts with regard to strength
and local plate buckling. Analysis results revealed
several regions of localized high stress as a result of
which Hatch recommended that a support bridge be
installed beneath the ducts to provide additional
support, particularly at the buckled region of the
northern duct.
QNI OFF-GAS DUCTS
As a result of a structural condition assessment on their
nickel ore roasting facility, Queensland Nickel Limited
(QNI) was made aware of the risk associated with the
condition of the two metre diameter off-gas ducts.
The ducts were commissioned circa 1972 and one of
the ducts (northern side of the building) exhibited major
buckling distortion caused by an implosion circa 1975.
Anecdotal evidence suggested that the ignition of dust,
which had accumulated in the duct, was the cause of
the implosion. The ducts spanned approximately 30m
between the roaster building and precipitator manifold
support tower and approximately 20m above the
ground. The ducts were only supported on saddles at
each end.
The nickel refinery operated on a twenty four hour a day
seven day a week basis and, coupled with a highly
Duct Stress Plot
The risk of failure was further amplified when a major
crack was detected in the northern duct shell in the
lobster-back bend at the roaster end of the duct. The
extent of the cracking was such that there was serious
concern that if immediate repair was not implemented
there was a serious risk of catastrophic structural
failure. The consequence of such an occurrence would
have been enormous as the area operations office, the
operators crib room and a substantial pipe gallery are
situated between the duct and the ground. Failure of
the duct would lead to major disruption of the plant
operation and have a high potential to cause a fatality.
In view of the above a temporary support, cantilevered
from the roaster building above the duct and located
beyond the cracked bend, was installed and the design
of a new lobster-back bend undertaken.

4 Structural Assets
Work on the support bridge design was temporarily
halted while the new bend was fabricated and installed.
The temporary support concept was so successful that
a similar “gallows” was designed and installed at the
precipitator end of the ducts to facilitate the removal of
the existing contilever truss supports which were
currently blocking the preferred position for the
proposed support bridge.
During the design phase of the project a number of
alternative methods of supporting the ducts were
investigated as there were many challenges to be faced
some of which included the following :-
Limited workspace in a highly congested refinery site;
Construction had to be undertaken while the plant
was in operation;
Unknown design loads (i.e. the amount of dust
accumulation inside the duct);
Unknown foundation capacity of existing buildings
from which bridge would be supported;
Capacity of existing buildings to carry the new loads
imposed by the support bridge; and,
Working in a hostile environment.
The congested work site proved to be the main
limitation. This was overcome by adopting an
innovative solution which worked around the site
restrictions. Temporary support beams were erected at
each end of the ducts to form a runway out to a slightly
less congested area to the north of the ducts adjacent to
one of the ore silos where crane access and
manoeuvring was possible. This concept was further
enhanced by the timely availability of a three hundred
tonne capacity crawler crane on the site.
Innovative design solution based on reducing the
degree of construction difficulty;
The bridge provides safe access for operation and
maintenance purposes.
Support Bridge in Place
The design solution may not be the most sophisticated
or cost effective but it is fit for purpose and was
undertaken in a compressed timeframe given the
operation and boundary constraints. The project was
safely delivered within the allotted timeframe and
budget without any loss of production or injury. For
further information contact Greg Gabb at
ggabb@hatch.com.au
OFFICE LOCATIONS AND
CONTACT PERSONS
Brisbane
152 Wharf Street, Brisbane, Queensland, 4000, Australia
Telephone: +61 7 3834 7777
Facsimile: +61 7 3832 3042
Contact: Dr. S Loganathan (Logan)
Townsville
Greenvale Street, Yabulu, via Townsville, Queensland, 4818,Australia
Telephone: +61 7 4720 6800
Facsimile: +61 7 4720 6821
Contact: Dr T.Langbecker
Prior to Installation of Support Bridge
The two pre-fabricated bridge segments were fitted with
sets of beam trolley wheels and lifted into place on the
temporary beams. The two bridge segment transverse
diaphragms were then butt welded in-situ and the
completed bridge rolled sideways along the temporary
beams into its final position underneath the ducts.
Once finally positioned the stricture was jacked up and
the beam trolley wheels removed allowing the bridge to
be lowered onto it's permanent bearings. The support
collars were then raised and fixed to the ducts. The
project provided the following value to the client :-
Reduction of the risk and consequences associated
with catastrophic structural failure including possible
loss of production and revenue;
Wollongong
26Atchison Street, Wollongong, New South Wales, 2500,Australia
Telephone: +61 2 4275 4200
Facsimile: +61 2 4275 4240
Contact: Glenn Avery
Perth
144 Sterling Street, Perth, WesternAustralia, 6000,Australia
Telephone: +61 8 9428 5000
Facsimile: +61 8 9428 5555
Contact: Rob Covella
Every effort has been made to ensure that the information contained in this
newsletter is correct. However, Hatch Associates Pty. Ltd. or its employees take no
responsibility for any errors, omissions or inaccuracies. For any enquires regarding
this newsletter including adding your name to the newsletter distribution list please
contact Greg Gabb (ggabb@hatch.com.au). Further information on the Structural
Assets Group and copies of all of our previous newsletters can be found on the
website: Http://www.hatch.ca/engineering/structural_%20Assets/Default.html
HatchAssociates Pty Ltd
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