UFC 4-171-05
1 January 2005
with change 25 October 2006
3-7.8.3.5 Nonreinforced masonry filler walls will be assumed to have no resistance
capacity and will be susceptible to damage. However, if there are many of these walls
that appear to provide substantial lateral load restraint without exceeding the allowable
stresses, they may be considered as part of the seismic resisting system.
3-7.8.3.6 When the strength of materials in concrete construction or the strength of the
load-bearing masonry walls is critical for the investigation or in determining the
necessary remedial measures, core samples will be taken and tested to determine the
values to be used for developing the conclusions.
3-7.8.3.7 Life safety of the existing structure is defined as meeting \ 75 /2/ percent of
the lateral resistance (strength requirements) required by code. However, any
strengthening or remedial measures to be provided will be designed to meet 100
percent of the lateral resistance of the code.
3-7.8.3.8 Refer to \ the latest DoD guidance set forth in UFC 1-200-01 /2/ for detailed
requirements for ductility in frames, connections to account for walls, isolation of
nonstructural masonry walls, clearances to account for story drift and support of
nonstructural and mechanical/electrical elements. Existing partitions and walls without
lateral support at the top, or without straying from a relatively rigid ceiling system near
the top, will be provided with lateral support against seismic forces. Mechanical and
electrical equipment will be anchored to resist seismic forces. All new partitions,
suspended ceilings, mechanical and electrical elements, and systems must be designed
in accordance with the latest DoD guidance set forth in UFC 1-200-01.
3-8
MeCHAnICAL
3-8.1
MDS/USAR Approved Materials and Systems
3-8.1.1 HVAC materials are of commercial quality, leaning towards the industrial end
of the scale. In most cases equipment is floor mounted in a mechanical room or
installed outside on a housekeeping pad. Rooftop equipment is seldom used except for
kitchen applications. NOC rooms should be served by small split system cooling units to
allow the central cooling plant to be deactivated in the unoccupied mode. HVAC
systems and equipment should be selected to provide the lowest life cycle cost. Refer to
ETL 1110-1-181 for chiller selections. When selecting equipment and systems,
consideration should also be given to keeping the service aspects of the installation
simple, allowing on-site personnel to perform the maintenance tasks rather than having
outside service contracts. There are five general HVAC system types used on MDS
projects in which the software will place the equipment items.
3-8.1.1.1 Variable Air Volume Systems include a central package air handler which
utilizes chilled water, and hot water coils, package chiller and boilers, and VAV boxes
with reheat. If a chilled water system cannot be justified by life cycle costs, air-cooled
condensing units may be used.
3-8.1.1.2 Split Systems include fuel-fired furnaces with condensing units or small air
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