81
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 80
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 TI 809-05 "Seismic Evaluation and Rehabilitation for
Buildings" 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 TI 809-04 "Seismic Design
for Buildings" requirements.
3.8
Mechanical
3.8.1 MDS/AR 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 floormounted 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.
UFC 4-171-05
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