Transcript Slide 1

INTRODUCTION TO CONSTRUCTION TYPES
Presenters:
Code Consultant:
Steven R. Winkel, FAIA, PE
The Preview Group, Inc.
[email protected]
Contractor:
Scott Smith
James E. Roberts-Obayashi Corp.
[email protected]
Architect:
Anne Torney
WRT | Solomon E.T.C.
[email protected]
INTRODUCTION TO CONSTRUCTION TYPES
For Infill Multi-Family Housing
1. The five basic construction types (as defined by the Building Code)
…and why it’s not that simple
2. Typical configurations for San Francisco housing
…and why there’s no such thing
3. Relative costs for different construction types
…and why they’re not important
4. Case studies
 Mid-rise vs. high-rise
 Options for 5 stories of housing over non-residential base
1. The Five Basic Construction Types
I
II
III
IV
V
Fire Resistance
Allowable Area
Most
Least
Allowable Height
Allowable # of Stories
Cost per Square Foot
Fire-Resistive: Concrete or Steel
Any Material with Fire Resistive Exterior Walls; Interior Any
Material
Wood: Heavy Timber
Any material
Rarely used for new
construction
© John Wiley & Sons, from Building Code Illustrated
Showing allowable building heights (with and without sprinklers) number of stories (with sprinklers)
and proportionate floor areas per story)
© John Wiley & Sons, adapted from Building Code Illustrated
TYPICAL CONFIGURATIONS
TYPE V
Fulton Grove
TYPICAL CONFIGURATIONS
TYPE V
Del Carlo Court
TYPICAL CONFIGURATIONS
TYPE V over TYPE I PODIUM
Fine Arts Building
TYPICAL CONFIGURATIONS
TYPE V over TYPE I PODIUM
8TH AND HOWARD
David Baker and Partners
TYPICAL CONFIGURATIONS
TYPE II or Type III over TYPE I
PODIUM
101 San Fernando
TYPICAL CONFIGURATIONS
Type I Midrise
Broadway Family Apartments
TYPICAL CONFIGURATIONS
Type I Midrise
PLAZA APARTMENTS
LMS/ Paulett Taggart Architects
TYPICAL CONFIGURATIONS
Type I High-rise
International Hotel
Herman Coliver Locus Architecture
RELATIVE CONSTRUCTION COSTS – Based on Construction Type
CONSTRUCTION TYPE
TYPE V:
# OF RES.
STORIES
WOOD
4 MAX
RESIDENTIAL FLOORS
METAL (plywood deck)
TYPE III: *
WOOD
RELATIVE
COST / SF
WHY
1.00
1.04
5 MAX
METAL (plywood deck)
1.03
+ fire-treated lumber framing at exterior walls
1.07
+ metal
TYPE II:
METAL (metal deck)
5 MAX
1.10
+ metal deck w/ concrete topping
TYPE I:
MID-RISE (concrete)
8 MAX
1.25
+ concrete frame
HIGH-RISE (concrete)
UNLIMITED
1.30
+ fire safety features
+ 1% per floor over 9
GARAGE/UNFINISHE
D T.I. SPACE
TYPE I:
GARAGE ON GRADE
(multi-level)
0.40
GARAGE ON GRADE
(single level)
0.50
GARAGE BELOW GRADE
0.60
* Man lift and possibly tower crane needed for buildings over 60’. Cost per square foot varies.
Relative costs courtesy of Scott Smith of the James E. Roberts-Obayashi Corporation
most efficient
+ shoring, waterproofing
WHY YOU SHOULD IGNORE THE PREVIOUS SLIDE
Relative construction costs are driven by type of construction
AND…
Site:
Shape, size, topography, soils, fire finishing & construction access, zoning
Unit Type:
Flats (double or single loaded), townhomes, studios, family units,
stacking, repetition
Ownership vs. Rental
Circulation
Ratio of skin to interior area
Size of project
Parking:
Yes or no, configuration, efficiency
Foundation Systems
Mechanical, Electrical and Plumbing Systems
Finishes
Et cetera…
CASE STUDY: MID-RISE vs HIGH RISE
High-rise (403)
Mid-rise
Floor level (not “height”) at less than 75’ feet
above lowest Fire Dept. access
Defined as floor level at more than 75’ above lowest Fire Dept.
access
Sprinklers required for R Occupancy
Sprinklers required
No elevator lobbies in sprinklered < high-rise
Elevator lobbies
No command center
Fire command center
≥4 stories, elevator on emergency power
Elevator on standby power = generator, in 2 hour rated room
(generator) or provide horizontal exit for
accessible means of egress (1007)
Fire alarm
Voice/alarm
No smoke control
Smoke control
Typ. stair shaft enclosures, 2 hour > 4 stories
Smoke proof enclosure
No standby power
Standby power for fire command, fire pump (if any)
Communication required for accessible means of egress
Stairway communication
No rescue air
Rescue air replenishment system in SF
WHY 75’ FOR A MID-RISE?
© John Wiley & Sons, from Building Code Illustrated
© John Wiley & Sons, from Building Code Illustrated
CASE STUDY: MID-RISE VS. HIGH-RISE
OPTION
8-STORY
MID-RISE
UNIT
S
S.F.
RELATIVE
COST/ S.F.
RELATIV
E COST
RELATIVE
COST/UNIT
66
97,500
1.25
$121,875
8 & 13-STORY
HIGH-RISE
100
136,000
1.30
$176,800
$1,768
13-STORY
HIGH-RISE
132
152,000
1.31
$199,120
$1,508
Costs per S.F.
increase…
$1,846
But costs per unit
may decrease.
CASE STUDY: FIVE FLOORS OF HOUSING
CASE STUDY: FIVE FLOORS OF HOUSING
SANSOME & BROADWAY
CASE STUDY: FIVE FLOORS OF HOUSING over NONRESIDENTIAL BASE
SANSOME & BROADWAY
CASE STUDY: FIVE FLOORS OF HOUSING - OPTIONS
OPTION
A
5 stories Type II metal
over 1 story Type I podium
B
5 stories Type III metal
over 1 story Type I podium
C
D
4 stories Type III wood
over 1 story Type III
concrete over 1 story Type
I podium
5 stories Type III wood
over 1 story Type I podium
TOTAL
#
STORI
ES
# OF
RELATIVE CONSTRUCTABILI
UNITS COSTS
TY NOTES
Most??
Fire-resistive construction throughout,
including metal deck floors with Levelrock
topping
Could have plywood decking at floors
6
50
Avoids dense framing @ lowest wood level &
associated mech. & elect. coordination issues
Least??
2-hour exterior walls w/ fire-treated lumber;
dense framing @ lowest wood level, which
can create utility coordination issues
Option D appeared to be the option with the least cost for this particular project, but the answer will vary
from project to project.