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Naveed Anwar, AIT Solutions
Progression of Structural Design Approaches Naveed Anwar, PhD
Naveed Anwar, AIT Solutions 2
Professional Education Integrated Solutions
ResearchAcademics The Asian Institute of Technology (AIT) promotes technological advancement and sustainable development in the Asia-Pacific region through its four key strengths
“To contribute towards the technological
development of the region through deeper and
expanded engagement and delivery of AIT’s
research, knowledge and expertise”
Naveed Anwar, AIT Solutions
Focus on solutionsdevelopment
Strengthen and deepen work IP protection and as incubation of ideas
Build on the strengths, vision & mission, and
resources of AIT
Enable greater engagement of AIT to be more beneficial to
the institute as well as to society as a whole
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Naveed Anwar, AIT Solutions
Milestones
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2010
2011
2012
20152013
2014
AIT Consulting AIT Solutions
2016
ACECOMS joined AITC
Increase in tall buildings, bridges, and special structures
projects
Organized the first-ever AIT Technology event
Habitech and AITS jointly work together
Repositioning & Rebranding
Naveed Anwar, AIT Solutions
Solutions
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Disaster Risk Reduction and
Management
Affordable Housing
Resilient Structures Skill and Capability
Enhancement
Project Reviews
IT and Software
Environment
Knowledge Sharing
Naveed Anwar, AIT Solutions
Habitech Center – Devilment of Building Technologies
Sustainable and cost-effective housing
Social infrastructure buildings for communities
Eco-friendly building materials, technologies that not only sustain life but also conserves our environment
AIT, through Habitech Center, has been instrumental in contributing significantly in developing
Naveed Anwar, AIT Solutions
Habitech Building System
Naveed Anwar, AIT Solutions 8
Why this Seminar?
And why are these topics important
Demand and Complexity is Increasing for the Built Environment
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(www.un.org)
Naveed Anwar, AIT Solutions
Population Growth is in Developing World
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Source: www.prb.org, volume no. 66, July, 2011.
Less Developed Countries will need more Low Cost Housing and infrastructure for nearly
2 Billon more people
Naveed Anwar, AIT Solutions 13
• Definition used by McKinsey Report
• Household (not individual)
• 30% of income for housing
• Household having 80% of median income should
be able to afford the housing
• This needs to be tackled worldwide!
50 % Household
Having More
50% Household
Having Less
Median Income
80% Median Income
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Japan, 4000m Sky Mile Tower, 1700 m JapanDubai City Tower, 2400 m One Dubai Tower, 1008 m
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Source: CTBU Report, 2015
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The Twisting Turning Towers Trend
Source: CTBU Report, 2015
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Needs Innovations in Structural Design Approaches
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Is my Structure safe?
(What level of Richter earthquake my structure sustain? Or what tornado level can it withstand,
or is it safe for explosions orHow long can it withstand the fire?)
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How long do we have
before the building will
collapse in this fire?
- Asks the Fire Chief from the structural
engineer
1974
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https://www.youtube.com/watch?v=FagbC09BO2o
Naveed Anwar, AIT Solutions
Ancient masterpieces were built before the modern approaches
Master builders had freedom to dream and to realize them
Naveed Anwar, AIT Solutions
Intuitive Design
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What a Structural Engineer said !
Hardy Cross, 1885-1959
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Intuitive Design
Code Based Design
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Main
Challenges !
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Win
d
Earthquake
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Stability
01
Strength
02
Deformation
03
Drift
04
Ductility
05
Energy Dissipation
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Motion Perception
07
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Naveed Anwar, AIT Solutions
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Spirit of the code isto help ensure Public Safety and provide formal/legal basis for design decisions
Compliance to letter of the code is indented to meet the spirit
Naveed Anwar, AIT Solutions 32
“Rebuilding of London
Act” after the “Great Fire of
London” in 1666 AD.
In 1680 AD, “The Laws of
the Indies” Spani
sh Crown
London Building Act of
1844.
In USA, the City
of Baltimorefirst building code in 1859.
In 1904, a Handbook of the Baltimore
City
In 1908 , a formal
building code was
drafted and adopted.
The International
Building Code (IBC) by (ICC).
European Union,
the Eurocodes.
Naveed Anwar, AIT Solutions 33
UBC, IBC
ACI, PCI, CRSI, ASCE, AISI,
AASHTO
British, CP and BS
Euro-codesChina, USSR,
Japan
Naveed Anwar, AIT Solutions
• Traditional codes govern design of general, normal buildings
Over 95% buildings are covered, which are less than about 50 m
• Not specifically developed for tall buildings > 50 m tall
• Prescriptive in nature, no explicit check on outcome
• Permit a limited number of structural systems
• Do not include framing systems appropriate for high-rise
• Based on elastic methods of analysis
• Enforce uniform detailing rules on all members
• Enforce unreasonable demand distribution rules
• Do not take advantage of recent computing tools
Naveed Anwar, AIT Solutions
Traditional
Design
approach for
Wind and
Earthquake is
different and is
often
in-consistent
and opposing
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Naveed Anwar, AIT Solutions 36
Seismic LoadWind Load
Depend on •focus of earthquake •Shaking intesity•ground conditions•Mass and stiffness distribution
Depend on•Wind speed• terrain • topography of the location• Force increases with height•Geometry and exposed area
m
ügv
A
Excitation is an applied displacement
at the base
force will be distributed along interior
and exterior lateral load resisting
elements
Excitation is an applied pressure or
force on the facade
force will act mainly on exterior
frames then transferred to floor
diaphragms
Naveed Anwar, AIT Solutions 37
For most buildings, dynamic wind response may be neglected
Gust factor approach predict dynamic response of buildings with reasonable accuracy
Structures are designed to respond elastically under factored loads
Structures are designed to respond inelasticallyunder factored loads
it is not economically feasible to design structures to respond elastically to earthquake ground motion
Design for Seismic EffectsDesign for Wind Load
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Naveed Anwar, AIT Solutions
Intuitive Design
Code Based Design
Performance Based Design
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Earthquake
Wind
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• Lack of explicit performance in design codes is
primary motivation for performance based
design
• Performance based methods require the
designer to assess how a building is likely
perform extreme events and their correct
application will help to identify unsafe designs.
• Enables arbitrary restrictions to be lifted and
provides scope for the development of
innovative, safer and more cost-effective
solutions
Naveed Anwar, AIT Solutions 42
Based on FEMA 451 B
Naveed Anwar, AIT Solutions 43
Structural Displacement
Lo
adin
g S
ever
ity
Resta
urant
Resta
urant
Resta
uran
t
Ha
zard
Vulnerability
Consequences
Naveed Anwar, AIT Solutions
Performance based design investigates at least two performance objectives explicitly
Service-level Assessment
Negligible damage with frequent hazards
(Earthquake having a return period of about 50)
Collapse-level Assessment
Collapse prevention under extreme hazards
(the largest earthquake with a return period of 2500 years)
Code’s arbitrary “Design Level”
Naveed Anwar, AIT Solutions
Intuitive Design
Code Based Design
Performance Based Design
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Wind
Earthquake
Naveed Anwar, AIT Solutions
Is this acceptable?Even though it satisfies CBD and PBD
Naveed Anwar, AIT Solutions
Intuitive Design
Code Based Design
Performance Based Design
Consequence and Risk Based Design
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Wind
Earthquake
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Code based was implicit, with not confirmation of response
PBD is explicit, can help to confirm the response and
performance level
Naveed Anwar, AIT Solutions
• For public and society, the performance criteria still does reduce the effects of the events, but it can reduce the risk level
• The non structural damage is not acceptable in modern buildings
• The disruption and loss goes much beyond the building
• Insurance companies want to have greater reliability of assessment of risk and damages
Naveed Anwar, AIT Solutions
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The trigger of an event is not important, the consequences of an event are
Naveed Anwar, AIT Solutions
Safety Studies (Probability and
Consequence Analysis)
Risk Quantification
Safety Critical Element
Design Accidental
Load
Structure Design
Naveed Anwar, AIT Solutions
Intuitive Design
Code Based Design
Performance Based Design
Consequences and Risk Based Design
Resilience Based Design
Wind
Earthquake
Naveed Anwar, AIT Solutions
Green Buildings Resilient Buildings
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Main authors : ArupSupported by USRC and many others
Naveed Anwar, AIT Solutions
Extreme Events should be handled Consistently
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Earthquakes, Wind, Blast, Progressive Collapse, Impact
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Naveed Anwar, AIT Solutions
RESILIENCE
Economic
Social
Organizational
Technical
Resourcefulness
Redundancy
Rapiditty
Robustness
Lower
Consequences
Faster
Recovery
More Reliability
4 Dimensions of
Resilience
4 Properties of
Resilience
3 Results of Resilience
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Economic Loses
Loss of Community and Culture
Loss of Quality of
Life
Go Beyond Life Safety
Naveed Anwar, AIT Solutions 58
Restaurant Restaurant
Resta
uran
t
Operational (O) Immediate Occupancy (IO) Life Safety (LS) Collapse Prevention (CP)
0 % Damage or Loss 99 %
Ref: FEMA 451 B
CasualtiesLowest Highest
Rehab Cost to Restore after eventLowest Highest
Retrofit Cost to Minimize ConsequencesHighest Lowest
Downtime for RehabLowest Highest
Impact on Sustainability of CommunityLowest Highets
Naveed Anwar, AIT Solutions 59
ARUP
Tools: How to design efficiently?
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• Initially, computers were used to
program the procedure we had
• Now, we develop procedures that
are suited for computing
Naveed Anwar, AIT Solutions 63
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Integrated 3D Bridge Design Software
Integrated Software for Structural Analysis and Design
Integrated Analysis, Design and Drafting of Building Systems
Integrated Design of Flat Slabs, Foundation Mats and Spread Footings
Nonlinear Analysis and Performance Assessment for 3D Structures
Design of Simple and Complex Reinforced Concrete Columns
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Thank you