The Three Dimensions of Safety, Damage and Recovery Define Your Building's Performance In A Major Disaster
The USRC Dimensions and Definitions are intended to provide
a consistent set of definitions for the performance evaluation of buildings
Performance evaluations for a given level of earthquake
shaking will vary across possible earthquakes of different strengths and
occurring at different distances from the building. The ratings below, when
used for earthquake performance, correspond to the average performance given a
single earthquake with ground shaking corresponding to that required for the
design of a new building. Ratings for other hazards will be developed by the
USRC in the near future.
Buildings that achieve a verified rating with minimum thresholds in each of the three dimensions of Safety, Damage and Recovery will receive either a CERTIFIED, SILVER, GOLD or PLATINUM designation, reflecting their expected level of performance. These designations can be displayed on the buildings themselves and with plaques and certificates.
USRC Safety Rating
The USRC SAFETY rating dimension reflects the expected performance of the building in terms of loss of life, injury and egress. A USRC SAFETY rating in this context is an indicator of the risk of personal injuries
of various types and seriousness, as well as loss of life.
USRC Damage Rating
The USRC DAMAGE rating dimension reflects an estimate of the cost
to repair the building after an event, as a percentage of the building’s
overall replacement cost (not including the replacement of contents), such that
it can continue to be used as it was at the time the rating was last issued.
DAMAGE is determined without consideration of
overall market conditions in effect following the event, such as increases in local construction costs, and it does not include factors such as
business interruption associated with loss of use or occupancy restrictions,
design fees, permit fees, historic preservation, or mandatory upgrades
triggered by building code regulations.
USRC Recovery Rating
The USRC RECOVERY dimension is an estimate of the time until a
property owner or tenant is able to enter and use the building for its basic
intended functions. It represents a minimum timeframe to carry out needed
repair and to remove major safety hazards and obstacles to occupancy and use,
but does not address several other factors that can delay the time to regain
function, including but not limited to: the condition of external
infrastructure (e.g. utilities, transportation) that provide access and services
to the building; damage or the post-event state of building contents; or the
condition of adjacent buildings.
The complexity and time needed to restore a building to
usable condition can increase quickly in relation to the degree of damage.
Delays in design, financing, and construction may include time until arrival of
special-order equipment or materials, increased prices, a lack of available
local design professionals or contractors in a community where many buildings
have been damaged, and longer than usual permitting and inspection wait times.
USRC Rating Definitions have been derived from technical
publications originally developed by the Structural Engineers Association of
Northern California (SEAONC). SEAONC granted the USRC permission to use these
documents. Any differences between USRC Ratings and related SEAONC documents
are solely the work of the USRC and do not reflect any opinion, endorsement, or
approval by SEAONC.
While US codes and engineering practices are among the most
advanced in the world, evaluations of building performance subject to natural
disasters include a significant amount of uncertainty: unknowns related to
forecasting actual event location, size and duration, the actual intensity to
which the building is subject, and the quality of the building design and
construction. Current building analysis, evaluation and correlation methods do
not address or remove all these sources of uncertainty.
Due to many factors including but not limited to
variations in construction, differing site conditions, and variations in
natural and man-made events, the performance evaluation of a single building
includes a significant amount of uncertainty.