BUILDING TECHNOLOGY DIVISION (CADD GRAPHIC)
Building Section Vignette
Draw a building section from plan given to you -- show foundation, walls, slabs,
roofs, beams, joists, ceilings, ductwork, and light fixtures. Be sure to show footings
and foundation wall in section. Typically use concrete spread footings about 2'-0"
wide, and 1'-0" thick symmetrically located under a 1'-0" wide concrete foundation
wall. You do not need to show reinforcing, but you may want to note the fact that
wall is reinforced concrete. Make bottom of footings 3'-6" below grade if building is
to be located in northern climate. Do not show foundation walls under interior
columns, but show footings under them, about 4'-0" square graphically, placed
directly under the concrete slab on grade for first floor. The reason for not requiring
a foundation wall under interior columns is that it is assumed that the ground will
never freeze under the building itself (as long as it is continually heated)
Note: If soils information show very poor soils, pile or pier foundations may be
necessary. If using piles, show pile caps. If using piles or piers, show a 2'-0" deep x
1'-0" wide grade beam under the exterior walls. Show pile clusters or piers under
interior columns.
Usually a basement will not be called for in the typical designs given. Do not show a
basement or any spaces underground unless specifically required in the information
given. There may be difficulties caused by excavation cut and fill requirements,
accessibility, water table depths, and possibly rock cutting.
First floor will probably be a concrete slab on grade. Show 6" thick slab with a 6"
thick gravel fill sub-base, a vapor retarder, and 2" of polystyrene insulation under
the slab edge, minimum of 2'-0" wide all around the perimeter of the slab.
Exterior wall finished materials should be brick and block cavity wall. Show exterior
face brick with a 3" wide cavity and 2" of rigid plastic insulation within the cavity,
and 8" thick concrete masonry unit back-up on inner wythe. Show flashing at the
bottom of the cavity and weeps at 16" on center. You may want to blend in some
limestone trim with the brick. Show the inner facing material to be 5/8" thick
drywall over 7/8" wide metal furring strips. Do not use exotic materials. Another
possibility would be either stucco over 10" thick concrete masonry units, with inner
facing being furred out and insulated with 3 1/2" thick fiberglass batts. Another
possibility would be to use a Dryvit type material (called "EIFS" Exterior Insulation
and Finish System), over 2" thick polystyrene insulation over 10" thick CMU. Try to
avoid metal stud exterior wall systems as they require special detailing and will take
more time. Since this is a complicated drawing, you should practice drawing it at
home prior to the exam, and get all of the components worked out. The scale will
probably be 1/4" = 1'-0" so you will not be able to show too much detail.
Use a sloping roof (gable or hip) if overall building width is not too large; if span is
more than 30 feet, use a flat roof with a parapet.
Show duct runs, supply and return from mechanical rooms.
Probably show bar joists for main floor structural system. These are usually 24" to
30" deep and are supported on steel wide flange beams which are, in turn,
supported on steel columns. Floor system is 2" thick concrete floor slab on 3" deep
steel deck.
Check construction type to make sure it is the right one: example UBC construction
types:
Type I: Fire resistive: concrete or fireproofed steel
Type II: Non-combustible: concrete or steel, fireproofed or not, depending on
level of protection required
Type III: Combustible: concrete, masonry, steel or wood, fireproofed or not
depending on level of protection required (normally "ordinary" construction,
wood joists and rafters with masonry bearing walls)
Type IV: Heavy timber, minimum sizes of beams and decks, no concealed
members
Type V: Combustible: concrete, masonry, steel or wood, fireproofed or not
depending on level of protection required (normally wood construction)
Note: Depending on which construction type you are assigned, you may or may not
have to fire-proof the structure. If you are required to use Type I construction, then
you must fireproof all steel. Since it is very difficult if not generally impossible to
fireproof steel bar joists, they should not be used for Type I construction. Instead,
in this situation, use concrete slab and beams, or concrete joist and beam systems.
Do not use steel deck and concrete slab with concrete frame.
Show air conditioning condensers in elevation on roof, if using a flat roof. If not
using a flat roof, probably ignore location for the section.
You probably will have a boiler flue projecting 2 feet above the highest point of the
roof. But do not get too concerned about that level of detail. This is not a test of
your engineering knowledge. Keep it in perspective with the life safety issues.
Structural layout vignette
Draw a floor or roof framing plan for a floor plan given to you. Do not use exotic or
unusual structural systems for the building. Do not use suspension cables, long
span steel girders, or large cantilevers. The scale of these buildings does not
warrent them. Do not attempt monumental space frames or three dimensional
trusses. Your safest bet for structure is bar joists, spanning 30 to 50 feet supported
on a simple masonry bearing wall.
If building is wider than 30', use a simple rectilinear 2-way beam system on
columns. Choice of steel or concrete my be yours to make. Floor slab should not
span more than 10' between beams. If you want to use steel bar joists, spacing
should be 2'-0" for floors and 4'-0" for roofs, and span should be limited to about
40'.
Accessibility ramp vignette
Design and draw an accessible ramp for a change in level on a given floor plan.
Make sure that all landings on ramps are 60" long. Where ramp makes a 90 degree
turn, make sure landings are 60" square.
Where there is a change in level, make sure that ramp is long enough (1:12 slope
maximum). Provide landings every 30 linear feet of ramp length. Provide railings on
both sides of every ramp with handrail extensions at top and bottom.
Mechanical and Electrical Plan vignette
Draw a reflected ceiling plan from a base plan given to you -- show ceiling tile
pattern, light fixture locations, exit sign locations, ductwork plan and diffuser
locations, air return grilles, and fire dampers. Technical information on lighting
levels required, ceiling heights, light fixture photometrics, and air distribution
requirements will be given. This task should be done very quickly. You will be given
lighting information from which you can derive a maximum light fixture spacing in
both directions. This will determine a ceiling grid pattern.
You will also need to show at least one supply diffuser in every occupied space, and
a return grille. You should make these square to fit into the grid system.
Use either a 2' x 4' or a 2' x 2' grid pattern, unless the problem states otherwise.
Do not have less than 1/2 of a tile dimension at edges of rooms. Start pattern in
center of room and work outward to produce a symmetrical pattern.
If you need to show light switches, show them at the strike side of the doors.
Show duct runs above the ceiling in plan connected to all supply diffusers and to
return grilles with branches.
Be sure to show fire dampers (and label them) at all penetrations of ducts through
fire-rated walls.
Show locations of exit signs above all exit doors in all rooms which will hold more
than 50 people, above doors to stairs, and to exit doors to the exterior.
Stair design vignette
Design and draw a stair which meets all codes. Calculate the width of stairs based on the occupancy load provided. Make stair minimum 44" wide. Make landings
minimum 44" wide. Show railings on both sides.
If the building is not fire-sprinklered, you must provide two 30" x 48" areas of
rescue assistance (spaces for wheelchairs) in at least one exit stair landing at the
second floor. You will need to provide one space for every 200 people on a floor.
Increase stair width minimum to 48". Again, you will need to use the occupancy load provided to calculate the actual width. Note that if building is provided with a supervised fire
sprinkler system, you do not have to provide these areas.
Show stair tread widths at 11" (although ADA does not regulate this, ANSI does).
Calculate numbers of risers required such that each riser is a maximum of 7" high.
Show railing extension at bottom of run of 1'-11" past the first riser. Railing
extension at top of run is 1'-0".
Roof plan vignette
Draw a roof plan for your building. This should be easy. Remember to show proper
roof slopes to drains at least 1/8" per foot. Show high and low points, parapets,
gutters, downspouts, mechanical equipment, roof vents, exhaust fans, and attic
ventilation.
Source: Frank Heitzman, AIA, Triton College.
