Mechanics-Basd and Prescriptive Codes

knapsackcrumpledMechanics

Jul 18, 2012 (5 years and 3 months ago)

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1
Mechanics
Mechanics
-
-
Based
Based
and
and
Prescriptive Codes
Prescriptive Codes
Engineered
Engineered
vs
vs
Prescriptive
Prescriptive
Construction
Construction
Mechanics
Mechanics
-
-
Based
Based


Traditional Code for Structures
Traditional Code for Structures
Designed using Engineering
Designed using Engineering
Mechanics
Mechanics
-
-
Based Design
Based Design


Typically Use Loads Determined for
Typically Use Loads Determined for
Site and Then Determine Load Path
Site and Then Determine Load Path
and Size Members According to
and Size Members According to
Physics
Physics
Codes Used: IBC and NFPA 5000
Codes Used: IBC and NFPA 5000


Mechanics Based
Mechanics Based
-
-
Design is Included
Design is Included
in the International Building Code
in the International Building Code
(IBC) and the National Fire
(IBC) and the National Fire
Prevention Association NFPA 5000
Prevention Association NFPA 5000
Building Code.
Building Code.


Traditionally, this type of design was
Traditionally, this type of design was
covered in UBC, BOCA, and National
covered in UBC, BOCA, and National
Building Code
Building Code
2
Prescriptive Codes
Prescriptive Codes


Typically restricted to residential
Typically restricted to residential
construction (one
construction (one
-
-
and two
and two
-
-
family
family
dwelling)
dwelling)


Includes detached houses and
Includes detached houses and
townhouses (Must have separate
townhouses (Must have separate
means of egress for each house.)
means of egress for each house.)
Prescriptive Codes
Prescriptive Codes


Design consists of laying out floor
Design consists of laying out floor
plan following a set of prescriptive
plan following a set of prescriptive
restrictions placed on the design
restrictions placed on the design
depending on the site, type of
depending on the site, type of
sheathing used, number of stories in
sheathing used, number of stories in
structure, and finish materials used.
structure, and finish materials used.
Prescriptive Codes
Prescriptive Codes


Traditionally controlled by the
Traditionally controlled by the
Council of Council of American
Council of Council of American
Building Officials (CABO) One
Building Officials (CABO) One
-
-
and
and
Two
Two
-
-
Family Dwelling Code
Family Dwelling Code


Now controlled by the International
Now controlled by the International
Residential Code (IRC)
Residential Code (IRC)
3
Mechanics
Mechanics
vs
vs
Prescriptive
Prescriptive


Shear Walls in IBC/NFPA 5000
Shear Walls in IBC/NFPA 5000


Segmented (Traditional Shear Wall
Segmented (Traditional Shear Wall
Design
Design


Perforated with Force Transfer (New
Perforated with Force Transfer (New
method to account for effects of
method to account for effects of
openings)
openings)


Prescriptive (
Prescriptive (


Conventional
Conventional
Construction
Construction


)
)
Mechanics
Mechanics
vs
vs
Prescriptive
Prescriptive


Shear Walls in IRC
Shear Walls in IRC


Prescriptive (
Prescriptive (


Conventional
Conventional
Construction
Construction


)
)


Fully
Fully
-
-
Sheathed Walls (Perforated Shear
Sheathed Walls (Perforated Shear
Walls Without Force Transfer)
Walls Without Force Transfer)
Shear Wall Design
Shear Wall Design


IBC/NFPA 5000
IBC/NFPA 5000


Use APA Tables,
Use APA Tables,
Mechanics Based Analysis
Mechanics Based Analysis


IRC
IRC


Percentage of Sheathing
Percentage of Sheathing
Requirements Depending on Floor
Requirements Depending on Floor
and Wind/Seismic Loading
and Wind/Seismic Loading
4
Floor Design
Floor Design


IBC/NFPA 5000
IBC/NFPA 5000


Use NDS/LRFD and
Use NDS/LRFD and
loading
loading


IRC
IRC


Span Tables assuming either
Span Tables assuming either
30 or 40
30 or 40
psf
psf
live loading and 10
live loading and 10
psf
psf
dead load.
dead load.