Download Building Codes - Architectural Structures - Lecture Slides and more Slides Structural Design and Architecture in PDF only on Docsity!
1
three
design codes,
building codes
Design & Codes Lecture 3 1
lecture
APPLIED ARCHITECTURAL STRUCTURES:
STRUCTURAL ANALYSIS AND SYSTEMS Structural Requirements
- serviceability
- efficiency
- construction
- cost
- other
Design & Codes Lecture 3 2 Architectural Structures III^ www.pbs.org/wgbh/buildingbig/
Structure Requirements
equilibrium
- safety
- stresses not greater than strength
- adequate foundation
Structure Requirements
stiffness
- stability of components
- minimum deflection and vibration
- adequate foundation
2
Design & Codes 5Lecture 3 Architectural Structures III
construction
- minimum material
- standard sized members
- simple connections and details
- maintenance
- fabrication/ erection
Structure Requirements
Design & Codes 6Lecture 3 Architectural Structures III
Design Procedure
- planning
- preliminary structural configuration
- determination of loads
- preliminary member selection
- analysis
- evaluation
- design revision
- final design
Design Procedure
- planning to establish
- function of structure
- criteria for optimum design
- code jurisdiction
- preliminary structural configuration
- arrangement of elements within form
- columns
- beams
- joists
- trusses
Design & Codes Lecture 3 7 Design & Codes Lecture 3^8
Design Procedure
- determination of loads
- structure weight
- moving loads
- severe, rare loads
- preliminary member selection
- based on configuration, determine loads on individual elements
- determine internal forces & stresses
- choose section to satisfy primary strength requirement
building codes
4
Design & Codes 13Lecture 3 Architectural Structures III
Building Codes
- occupancy
- construction types
- structural chapters
- loads, tests, foundations
- structural materials, assemblies
- roofs
- concrete
- masonry
- steel
Design & Codes Lecture 3 14 Architectural Structures III
Building Codes
- adoptable codes
- Southern Building Code Congress International (SBCCI)
- Building Officials & Code Administrators International (BOCA)
- International Conference of Building Officials (UBO)
- International Building Code (IBC)
- attempt to get one unified code in 2000
Design & Codes Lecture 3 15 Architectural Structures III
Code Reduction of Live Loads
- now allowed for ordinary roofs
- for live loads 100 lb/ft^2
- area supported 150 ft^2
- not a garage
- reduction of 0.08% /ft^2 allowed
- reduction can’t exceed
- for live loads > 100 lb/ft^2
- live load reduction of 20% on columns
Lo
R 23. 11 D
(ALTERNATIVE)
Design & Codes Lecture 3 16 Architectural Structures III F2008abn
Standards
- criteria for quality
- American National Standards Institute (ANSI)
- American Society of Testing and Materials (ASTM)
- materials
- Brick Industry Association (BIA)
- Portland Cement Association (PCA)
- National Concrete Masonry Association (NCMA)
5
Design & Codes Lecture 3 17 Architectural Structures III
Structural Codes
- prescribe loads and combinations
- prescribe design method
- prescribe stress and deflection limits
- backed by the profession
- may require design to meet
performance standards
- related to material or function
Design & Codes Lecture 3 18 Architectural Structures III
Structural Codes
- American Concrete Institute (ACI)
- American Institute of Steel Construction
(AISC)
- Precast/Prestressed Concrete Institute
(PCI)
- Post Tensioning Institute (PTI)
- Structural Joist Institute (SJI)
- National Design Specifications (NDS)
- National Forest Products Association
Design & Codes Lecture 3 19 Architectural Structures III
Design
- factors out of the designer’s control
- factors within the designer’s control
- choice of material
- “cost” of failure (F.S., probability, location)
- economic design method
- analysis method
Design & Codes Lecture 3 20 Architectural Structures III
Design Methods
- different approaches to meeting
strength/safety requirements
- allowable stress design (elastic)
- ultimate strength design
- limit state design
- plastic design
- load and resistance factor design
- assume a behavior at failure or other
threshold and include a margin of safety
http://mceer.buffalo.edu
7
Design Methods
- load and resistance factor design (LRFD)
- materials aren’t uniform 100% of the time
- ultimate strength or capacity to failure may be different and some strengths hard to test for
- RISK & UNCERTAINTY
A
P f (^) u u
Design Methods
- loads on structures are
- not constant
- can be more influential on failure
- happen more or less often
- UNCERTAINTY
- Resistance factor - Load factor for (D)ead & (L)ive load
(^) D PD LPL P u
- distributed by tributary areas
8
tributary area tributary^ width
area
load
w
width
Load Paths
Design & Codes 32Lecture 3 Architectural Structures IIIARCH 631 F2008abn
Load Paths
10
Design & Codes 37 A
ASD Load Combinations
- D
- D + L
- D + (Lr or S or R)
- D + 0.75L + 0.75(Lr or S or R)
- D + (0.6W or 0.7E)
- D + 0.75L + 0.75(0.6W or 0.7E) +
(0.75Lr or S or R)
ASCE- 7 (2010)
