8.5 Existing Construction
8.6 Historic Buildings
Modernization
Historic buildings are covered by these criteria in the
same manner as other existing buildings (see Existing
Existing structures undergoing a modernization should
Construction Modernization in this section).
be upgraded to new construction requirements when
required by the risk assessment except where noted in
Progressive Collapse, below. The requirements of new
construction apply to all major additions and structural
modifications.
Protection Levels. Risk assessments based on the new
construction criteria shall be performed on existing
structures to examine the feasibility of upgrading the
facility. The results, including at a minimum recom-
mendations and cost, shall be documented in a written
report before submission for project funding.
Progressive Collapse. Progressive Collapse analysis must
be performed if:
1. The building is to be upgraded for seismic forces
2. The building structural frame will be exposed as part
of the current scope of work making any structural
upgrade for preventing progressive collapse appropriate at
this time.
3. The exterior faade of the building is to be removed
making structural upgrade of the perimeter structural
system appropriate at this time.
Prior to the submission for funding, all structures shall be
analyzed according to requirements for new construction,
and a written report shall clearly state the potential
vulnerability of the building to progressive collapse. This
report will be used as a planning tool to reduce risk.
Findings of the design-analysis shall be incorporated into
the project's risk assessment and include the methodology,
the details of the progressive collapse analysis, retrofit
recommendations, cost estimates, and supporting
calculations.
Edward T. Gignoux U.S. Courthouse, Portland, ME
249
SECURITY
DESIGN
8.5
Existing Construction Modernization/Historic Buildings
Revised March 2005 PBS-P100
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