5 - Modern Steel Construction

• would best respond to the identified criteria
in a faci lity in which non-combustible,
non-fire-rated construction is permissible,
the ad vantages of combining a steel
column and girder system with a precast,
prestressed long span floor deck become
obvious. Based on this initial assessment,
we have been progressively refining this
"hybrid" structure during the past few
years.
The character of the structure is such
that it is readily adaptable to different orga
nizations of parking garage layouts, as
has been demonstrated by its use to date
on sloped-floor, external ramp, and splitlevel
garages.
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Becton Dickinson & Company
@ RKING STRUCTURES]
Although our fi rst-generation use of a
hybrid structure was adopted for a municipal
parking facility in Cambridge, MA, the
principal features discussed above were
not all evident until the second-generation
with the construction of the Phase I parking
fa cility for the Becton Dickinson &
Company Headquarters in Franklin Lakes,
j .
The Becton Dickinson structure is
founded on spread footings. Paired steel
colu mns interconnected by paired plates at
10' on center vertically were first erected to
the full height of the structure and the columns
were then interconnected at each
fl oor with steel gi rd ers at each of the two
column lines. This arrangement provided
lateral stability in the transverse direction
by the ladder frame cantilevering from the
ground in the longitudinal direction by
conventional frame action. It immed iately
provided a perma nent and stable support
system on which to ra pidly erect the precast
double tees that were welded to the
top flange of the girders.
The fl anges of the double tees were
welded together in the manner normally
provided for pre-topped tees, and a connection
made between the end of the tees
in a shaped cast-in-place concrete in fill that
incorporated the fl oor and roof drains.
This approach eliminated the structural irregularities
normally associated with such
ramps.
One of the benefits of the paired column
is the very open, visually uninterrupted
floors with no hidden areas. This provides
a sense of securi ty to the user. Another
benefit is that the plumbing and fire protection
piping and the electrical conduit
ca n be protected from automobiles by
being located in
the chase between
the pair of columns.
At the
Becton Dickinson
facility, steel also
was used extensively
for automobile
and pedestrian
ba rrier elements at
the perimeters in a
ma nner that ensured
the visual integrity
of the de­
Sign. All structural
steel, which was so
configured and arranged
as to make
surfaces readily accessible
for repainting
in the future,
was provided with
a three-pa rt coating
consisting of a zincrich
primer, epoxy
second coat, and
urethane fini sh to
ensure a durable
and long-lasting
fini sh. Structural
steel fabrica tor was
AISC-member
Leonard Kun kin
Associates, Line
Lexington, PA.
Subsequent to the completion of this facility,
a nu mber of refi nements were introduced,
includ ing the elimination of all field
welding associated with the structural
steel. It was determined that this would
improve the manner of assembly of the
several structural elements and retain the
integrity of the coating system.
Un iversity of Massach usetts Medical
Center
Two of the parking structures adopting
the third-generation approach are th ose at
the University of Massachusetts Medica l
Center in Worcester and the second ga rage
fo r the Becton Dickinson & Company
H eadquarters.
Thc Medica l Center garage provid es
1,498 spaces on six levels and was built for
just over $8.5 million, or $5,688 per space.
In this structurc, connections of the steel
columns and girders were a ll bolted with
the moment connections being made after
the erection of the precast floor members
Shoum at top ,:- n detail
of the barrier dcwellts
at the 8£'('1011 D;ek",s