Operational Readiness Training Complex

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Nov 25, 2013 (3 years and 6 months ago)

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Operational Readiness Training Complex

Ft. Drum, New York


Structural Narrative

Rev 1


Jun
29
, 2011




Operational Readiness Complex


Barracks:


The
two
Barracks will
each consist of
a 4 story building with 12 ft. floor to floor heights
and

a sloped
roof.
The proposed structure will consist of load bearing CMU walls. The 2
nd
, 3
rd

and 4
th

floors will be
constructed
of a normal weight concrete

slab on

a deep 8”

metal co
mposite

deck.

An additional
discussion of the selected floor system is provided below.

The total depth of the floor will be 10 ½”.

The
roof will consist of
a 1 ½”, 20 gage metal deck bearing on
light gage metal trusses
. These will in turn
bear
on the CM
U walls. The trusses will allow for
the desired sloped roof building profile.

The lateral
system for the building will consist of masonry shear walls.


As per the room finish requirements, all interior walls within the Barracks will be CMU.


UFC 4
-
023
-
03 “Design of Buildings to Resist Progressive Collapse”
revised through Jan. 2010 makes
numerous changes to the Tie Force method. The main items of interest were the requirements for both the
transverse and longitudinal tie reinforcing to be continuous thr
ough the entire floor system. Initially, the
2
nd
, 3
rd

and 4
th

floor construction for the Barracks was conceived to be an 8” precast plank with
a
2 ½”
concrete
topping

slab
. It was expected that the longitudinal reinforcement would either be buried in the
plank itself or in one of the cores and a mechanical coupler would be used to attach strands and bars from
plank to plank, thus attaining continuity. The transverse ties would then be placed within the topping slab
where they could easily be lapped. At t
he edges of the building and major openings we would have tied
the

tie
reinforcement via seismic hook to the peripheral ties. Due to cost implications an investigation was
also carried out into placing both longitudinal and transverse ties within the toppi
ng slab. This however
would have required a thicker topping and as a result a

heavier system. T
he guideline

also

requires that all
bars in the topping slab be mechanically fastened to the plank

so that in the event of a failure, the plank
can hang from the reinforcement. T
he bond between the topping and plank itself is insufficient to
withstand the massive deformations associated with catenary actions.
In addition to the difficulties
associated

with the placement of these ties, there were safety issues to consider. Due to the tight tie
spacing required, mechanical anchors would be required at an extremely tight spacing and prior to placing
of the topping slab these pins would have posed a safet
y issue to those working on the plank. These
safety issues and the cost associated with using the plank to meet the progressive collapse requirements
made the plank an unfeasible approach.


As such we decided to pursue an alternate approach which would involve using a concrete slab on deep
composite metal deck.
The deck itself is a total of 8” deep with flutes spaced approximately 2’
-
0” O.C.
The total depth of the floor with concrete include
d would be 10 ½”. Reinforcement for this slab would be
placed directly at the bottom of each flute. This system does offer numerous benefits. Overall depth of
the floor is decreased beyond what would possibly be achieved with the plank system, or with a

smaller
composite slab bearing on steel supports. This floor system also has a load bearing capacity in excess of
what is required in the barracks and is able to span directly between CMU or Steel supports without
requiring additional framing.
The need
for a topping slab would be eliminated. As a result t
he weight of
the system is also less than that for plank or cast
-
i
n
-
place concrete slab which helps to decrease the sizes
of the foundations and helps to decrease the seismic loading on the building.
F
inally, the system allows
us to meet the requirements of progressive collapse by allowing for the placement of the longitudinal and
transverse ties directly into the slab.
An attachment between the lateral/ transverse ties and peripheral ties
would also b
e easily accomplished with seismic hooks.
The reinforcement can be placed and lapped as
required prior to the placement of the concrete. The system was chosen for its efficiency and ability to
meet the UFC guidelines.


The building’s foundation will

consist of continuous concrete wall footings designed to bear on
3
.0 tsf of
compacted fill or in
-
situ
fill

as confirmed by the final geotechnical report. Compacted fill will be to final
grade using material excavated during construction plus additional o
ff
-
site fill as required. The ground
floor will consist of a 5” slab
-
on
-
ground.


Officer’s Quarters


The officer’s Quarters will be a two story building occupying a footprint of approximately 11,259 SF.
Similar to the Barracks, the structure for this b
uilding will consist of CMU load bearing walls. These
walls will also serve as the building’s lateral system.


The 2
nd

floor will be constructed of a 3” deep, 18 gage metal floor with 2” of normal weight concrete, for
a total depth of 5”. The deck has
been designed for single span conditions and will bear on steel angles
bolted directly into a bond beam running within the CMU wall. The concrete will be poured over the top
of the wall to lock the floor

together in

between bays and provide a suitable rig
id diaphragm for the
transfer of lateral loads.


The
roof will also consist of light gage metal trusses bearing directly on the walls.


As with the Barracks, all walls, including non load bearing walls will be built with CMU. The planks will
be designed

to support the added load of CMU partitions.


As the building is less than three stories the provisions of UFC 4
-
023
-
03 are not required and the building
does not need to be designed for progressive collapse.


The foundation will be similar to that de
scribed for the barracks.



Vehicle Maintenance Shop


The Vehicle Maintenance shop will be a steel framed building with masonry shear walls. The roof will
consist of a 1 ½” deep, 20 gage metal deck bearing on light gage metal trusses. These trusses will

in turn
bear directly on the steel frames below.


Framing will be provided in both the Warehouse and Vehicle Maintenance bay to maintain the required
clear spans of 55 ft. and 64 ft respectively. Supplemental framing will also be provided in the Vehicle
maintenance to support the specified 10 ton crane. The building height will be set to allow for the
required 20ft. hook height.


The foundation
design will be similar to

that of
the
Barracks consisting of continuous wall footings and
isolated footings t
o support the steel columns.

The
Slab
-
on
-
ground will be designed for truck loading
associated with the use of the
maintenance

bay
, including any required depressions.


Battalion Headquarters


The Battalion Headquarters will be built primarily out of load bearing light gage metal framing. The roof
will consist of a 1 ½” metal deck bearing on light gage metal trusses. Supplemental steel framing will be
provided to aid in the support of the ligh
t gage metal trusses. The light gage metal walls will also act as
shear walls to carry the buildings lateral forces.


As with the other buildings the foundation will consist of both continuous wall footings and isolated
footings for the steel columns. T
he ground floor will be a 5” slab
-
on
-
ground bearing directly on structural
fill or in
-
situ
-
soil.


Special care will be provided in the classroom spaces. Steel will be provided to ensure that no
obstructions are provided here. Heavy steel beams will be
required to accommodate the folding partitions
which divide the three classrooms from one another. The steel beams will be built
-
up plate girders as
they will act as a point of support for the light gage trusses and will also carry the folding partition.

The
plate girders will be designed to minimize live load deflection as required.


Dining Facility:


Similar to the Battalion Headquarters, the Dining facility will be primarily built out of load bearing light
gage metal framing. The light gage metal wal
ls will also be used as shear walls to carry the Supplemental
steel will again be added to provide additional support for the roof structure. The roof will be similar to
that described for the Battalion Headquarters.
The layout of the steel framing will be such that the dining
spaces will remain open.


The foundation will once again consist of both continuous wall footings and isolated footings for steel
columns. The ground floor will be a 5” slab
-
on
-
ground.


Compa
ny Shed:


The Company Shed will be a pre
-
fabricated building designed by the manufacturer as per the
specifications and design criteria in the RFP.


The building’s foundation will be spread footings. Slab
-
on
-
ground will be a minimum of 5” thick.
Tensio
n ties within the slab will be provided to carry the thrust forces imparted to the foundation by the
prefabricated building frames.