Ref: 6571L02
05 February 2016
9(2)(a)
Dear
St Gerard’s Stage 1 Seismic Strengthening
Structural Engineering Consultancy Services
Further to our recent discussions we are writing to you to summarise the wider
project issues and our proposed Structural Engineering Services associated with
the project.
We have called the project “Stage 1” in terms of the strengthening work in that the
target
%NBS is only 34%, just sufficient to prevent it from being classified as
Earthquake Prone. This is a strengthening level we would not normally
recommend in that it lifts the building only to what is currently considered a
minimum level of safety, and as well does not provide any buffer to future changes
in codes/standards that may drop this
%NBS level again. However in unusual
circumstances such as this we feel that the stage can be an important first step
along the road to sustainable heritage management of the complex. The demands
under the Official Information Act 1985
on us will be to come up with a scheme that can be “added to” in the future without
significant re-work of what is done in Stage 1. In this case there is not the budget
to firstly come up with a 67% plus scheme and then de-tune it to 34%: we will
instead be needing to use our experience and some innovation to further this goal.
Our assessment of 34%NBS will be for an Importance Level II or “normal” building.
This assumes that no more than 300 people can gather together in the church at
once, and that the regulating authorities don’t believe the building should be
Importance Level III due to its heritage status. We believe that in terms of
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preservation, skilled choices of strengthening method can control damage better in
the more likely range of moderate earthquakes the building will experience than
simply increasing the design load levels by 1.3x for the IL III classification.
Consulting Structural Engineers
94 Dixon Street, PO Box 27-153, Wellington 6141
Telephone (644) 385-0019, E-Mail: [email address]
St Gerards Preliminary Strengthening Page 2
As discussed, we wish to cover three aspects of the strengthening process below:
firstly our engagement terms and the options we propose, secondly the timing of
associated degradation investigations to ensure the materials in the building can
outlast the design life, and thirdly the involvement of the remainder of the design
team to develop the final documentation.
The target of our work covered by this proposal is to establish a budget from which
to fundraise for the project. The more work we carry out at this stage, the lesser
design risk will need to be factored into the budget estimate. The design risk is a
product of the amount of analysis/design we have done, the experience of the
person putting together the estimate, and the extent of structural investigation
carried out. This third item will be discussed in the following section. In addition to
design risk, there will also be a construction contingency appropriate to this type of
building to deal with the inevitable unforeseen extras that arise when parts of the
existing structure are opened up.
We initially propose to carry out only “Developed Concept” as the minimum level of
work we feel is appropriate. This will require the person/parties putting together the
estimate (QS, Contractor or combination thereof) to have significant skill in
estimating for the staging/sequencing and disruption/make good allowances which
will not be fully described in the documentation. We have also outlined the
additional fee we would require to carry out full Preliminary Design, the more usual
stage design is progressed to for budget costing. We would obviously prefer to do
the more extensive scope as it allows us more time to consider options and
properly define the issues. However we understand the difficult funding framework
you are in and hence give you the option.
For the Monastery, we will first analyse the existing structure to properly
understand its existing strengths: a Detailed Seismic Assessment (DSA). This best
allows us the opportunity for finding areas where we can complement or
manipulate its existing capacity, rather than adding a whole new seismic system to
the building. For the church however, given it is more earthquake prone and
structurally a simpler building, we will instead progress straight to the concept
design, in which we will analyse the existing capacities with the new strengthening
in place.
Durability under the Official Information Act 1985
In addition to the structural strengthening, we will need to consider the durability of
the concrete in the building: we would not want to design or worse strengthen the
building without addressing this if we found that corrosion of the underlying
reinforcement or “concrete cancer” was soon to onset. Visual examination of the
building suggests that its paint and the thick plaster may have preserved the
underlying concrete. However we would not want to proceed much beyond
Preliminary Design without investigating this issue. Investigations would involve a
specialist taking invasive samples from the outside of the building in several
locations and chemically analysing for carbonation and chloride ingress. As with
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any risk, we would encourage this to be undertaken as soon as funds permit, as
the costs are likely to be substantial, say $15-20k.
Consulting Structural Engineers
94 Dixon Street, PO Box 27-153, Wellington 6141
Telephone (644) 385-0019, E-Mail: [email address]
St Gerards Preliminary Strengthening Page 3
Design Team
Any strengthening project requires more than just the Structural Engineer to carry
out the work. Regulations insist as a minimum a current Fire Report is produced,
and the building to be upgraded to a
s near as reasonably practical (ANARP) to
current code levels. We discuss the team members and their input required below:
•
Architect - to attend on the making good requirements around the
strengthening interventions, but more importantly form a holistic project
thinking and co-ordination role for the design team
1985
•
Heritage Architect (which may be part of the Architect) - to provide critique
to the design options, guidance as to the relative importance of various
features, and provide written documentation support to the Resource
Act
Consent application. They will also guide consultation with the various
heritage regulators.
•
Fire Engineer – it is essential that a skilled Fire Engineering Consultant is
employed to properly assess the current risks, and where appropriate to
use the ANARP argument to justify areas which will not exactly comply. A
heritage building gives the greatest scope for the ANARP argument,
however the building’s mixed use with gathering, working and sleeping all
within the same structure may be challenging.
Information
•
Geotechncial Engineer – the work by Tonkin and Taylor to date is sufficient,
with our experience of Wellington rock conditions, to allow us to complete
Preliminary Design. However they may need to be further involved beyond
this, and possibly carry out further investigations, depending upon the
strengthening solution selected.
Official
As part of setting up the budgeting, we will need to project fees to completion. With
an agreed concept and pricing both ourselves and the above consultants should
be able to estimate these fees. The exception to this may be Resource Consent,
the
for which we all are a little at the mercy of the extent of detail that may be required
by the regulating authorities.
For you to benchmark our structural fees beyond what is proposed below, we
would look to align them to 10% of the structural portion of the work, covering all
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stages. We would be happy for a Quantity Surveyor experienced in this type of
work to review this on your behalf, for probity’s sake.
1.0 Scope of Engineering Services
1.1
Monastery Partial Detailed Engineering Assessment
Weigh the structure
Develop a wall-based 3D computer model to analyse the distribution of loads.
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Carry out an analysis of the first floor and roof transfer diaphragms.
Review the key gable walls for face loading.
Review tie forces in the timber structure at roof level.
Brief summary report.
Consulting Structural Engineers
94 Dixon Street, PO Box 27-153, Wellington 6141
Telephone (644) 385-0019, E-Mail: [email address]
St Gerards Preliminary Strengthening Page 4
1.2
Monastery Developed Strengthening Concept
Preliminary Calculations for the key defining elements in the strengthening
design
Extrapolation/interpolation to cover the whole scheme
Workshop to review the proposals and brainstorm alternatives
Further calculation to complete concept or preliminary design
Sketch documentation to allow a budget to be established by a Quantity
Surveyor or builder experiences with complex heritage retrofit.
1.3
Church Developed Strengthening Concept
Preliminary Calculations for the key defining elements in the strengthening design 1985
Extrapolation/interpolation to cover the whole scheme
Workshop to review the proposals and brainstorm alternatives
Further calculation to complete concept or preliminary design
Sketch documentation to allow a budget to be established by a Quantity Surveyor
Act
or builder experiences with complex heritage retrofit.
2.0 Conditions of Engagement
The Conditions of Engagement shall be in accordance with the ACENZ Shortform Model
Conditions of Engagement (Copy enclosed)
3.0 Professional Liability
The liability of the consultant to the client in respect of our services shall be limited to
Information
$500,000. We have professional indemnity insurance in place to cover this amount. We
advise that we exclude any liability on any matters relating to Asbestos or contaminated
ground.
4.0 Payment
Official
4.1
Monastery Partial Detailed Engineering Assessment
Lump sum fee of $15,000 plus GST payable on monthly pro rata basis during the
design phase.
the
4.2
Monastery Developed Strengthening Concept
Lump sum fee of $12,000 plus GST payable on monthly pro rata basis during the
design phase.
Additional $10,000 if this were to be taken to the Preliminary Design phase.
4.3
Church Developed Strengthening Concept
Lump sum fee of $15,000 plus GST payable on monthly pro rata basis during the
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design phase.
Additional $10,000 if this were to be taken to the Preliminary Design phase.
4.4
Work Beyond Scope of Work (with prior agreement of client)
On a time basis, valid until December 2017;
Director
$220/hour plus GST
Associate
$180/hour plus GST
Senior Design Engineer
$160/hour plus GST
Design Engineer
$130/hour plus GST
Senior CAD Operator
$140/hour plus GST
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CAD Operator
$1200/hour plus GST
Disbursements at cost
Consulting Structural Engineers
94 Dixon Street, PO Box 27-153, Wellington 6141
Telephone (644) 385-0019, E-Mail: [email address]
St Gerards Preliminary Strengthening Page 5
We trust that this provides the information that you require and adequately
represents our discussions to date.
Yours faithfully
Alistair Cattanach
DIRECTOR
160205 AGC/JDC/AWT
under the Official Information Act 1985
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Consulting Structural Engineers
94 Dixon Street, PO Box 27-153, Wellington 6141
Telephone (644) 385-0019, E-Mail: [email address]
