Piers make up a large part of the maritime infrastructure, yet
their life cycle costs are little discussed in the available
literature. A study for the U.S. Coast Guard focused on the M&R
(sustainment) costs of two types of piers-concrete and timber. We
found a substantial difference (30 percent) in costs between the
two types and, in comparison, an apparent understatement (at least
50 percent) of M&R costs by one well known reference.
Our models consist of component level descriptions of typical
fixed piers matched with scheduled repair tasks and service
calls.[1] The tasks are calibrated for a specific area in terms of
labor rates, material costs, and climate, and then used in
specialized software to generate a 50-year cost profile.[2]
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Replacement Value
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M&R Costs (Sustainment)
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Concrete Pier
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$417
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$10.66
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Timber Pier
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$220
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$7.26
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Costs are per gross square foot, expressed in $2010 and
normalized to Washington D.C.; M&R costs are averaged for a
model pier over 50 years following construction.
Source: Whitestone Research
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The estimates differ by $3.40 per square foot depending on pier
type, with the difference driven largely by the periodic
replacement of fenders, pilings, and decking. Note that the
concrete pier accommodates heavier traffic so is not directly
comparable in terms of the service provided.
In another comparison, we found our estimates differ greatly
with those published by the U.S. Department of Defense. According
to the DoD Facilities Pricing Guide, the sustainment costs
for a pier should be $3.51 per square foot, less than half of our
estimates. The Pricing Guide makes no distinction by pier
type.
The reasons for the difference are unknown. It is not because of
inconsistent definitions; the Pricing Guide and our model
use the same definition of sustainment costs. Instead, we suspect
differences in data quality and the estimation method.
Does it matter? Yes. Knowledge of life cycle costs are
instrumental in the prioritization of projects, the evaluation of
alternative technologies (such as floating piers), and the
forecasting of budget requirements.
With respect to sustainment budgets, the difference in estimates
can have a profound impact. Together, the U.S. Navy and Coast Guard
are responsible for maintaining roughly 19 million square feet of
piers. Based on the Pricing Guide, the annual requirement
for this inventory is $67 million, while alternative estimates
based on this study would range from $138 to $202 million.[3]
Click here to view
Whitestone Square Foot Cost Profiles for Piers.
- Michael Towers
[1] The component inventories and selected task frequencies were
defined by the marine engineering firm Moffatt and Nichols.
Much of the task and cost data were taken from the Whitestone
Facility Maintenance and Repair Cost Reference 2010-2011 (Santa
Barbara: August 2010).
[2] M&R cost profiles were generated by the MARS facility
Cost Forecast System (version 8.5). Other operating costs are also
available. A 50-year service life is a common assumption in
engineering and economic studies regarding pier construction or
renovation. The average age of existing U.S. Navy and Coast Guard
piers is approaching 50 years; in the case of the Coast Guard,
roughly 20 percent are over 50 years old.
[3] For simplicity, we assume that all piers are located in the
Washington D.C. area. In the Coast Guard study, we calibrated
the estimates for actual pier location and age.