Jonathan park beb801 presentation 2016 sem 1

Jonathan Park
n7211643
10/06/2016

Understanding of lateral
actions and response
Two key features:
› Aspect ratio (z:w)
› Stiffness
Scope of topic
› Height restriction
› Geographical location
› Support conditions
› Testing
 BEB801: Report 2-A, Jonathan Park - 10/06/2016

Limit state design
Ultimate
Serviceability
Environmental
Wind
Seismic
Man-made
Combined loading
Differentiation

Industry Standards
Safety limits
Factored loading
› Dead Loads (G)
› Live Loads (Q)
› Lateral Loads (W,E)
Response criteria
› Deflection
› Bending moment
› Shear force
› Axial force
› Torsional force
Ultimate vs. Serviceability

Load cases
Factors of safety
› Strength
› Stability
Limits of element
› Size
› Shape
› Material
Defect factors
Types of ultimate failure
› Element failure
› Structural failure
› Cladding failure

Main difference from ultimate
Types of serviceability failure
› Deflection
› Cladding failure
› Local deformation
› Minor failure
› Vibration
Comfortability of occupants

Vibration
First (natural) mode
Caused by excessive lateral force
Structural acceleration
Human tolerances (milli-g’s)
Probability of exceedance

Creation of wind
Importance of location
Importance of wind relative to
height
Cantilever formula -
Different types of response

Variation in velocity
Variation with respect to height
Variation with respect to direction

AS1170.2 Design process
› Building characteristics
› Base wind speed
› Site wind speed
› Cfig and Cdyn
Wind tunnel testing
Wind gradient

Building aerodynamics
Vortex shredding
Mode of failure
Mitigation of wind response
› Base overturning moment

Aerodynamic shape variables

Importance of understanding
Australian Standard
Wave patterns
› Body
 P-waves
 S- waves
› Surface
 Love
 Rayleigh
Lateral acceleration

Response depends on:
› Height
› Stiffness
› Aspect ratio
Vibration
V
Modal frequencies
V
Resonance

Important aspects of seismic design
› Continuity
› Stiffness
› Regularity
› Redundancies
› Sacrificial yield mechanisms (Plastic hinges)
Vibration control
› Stiffness
› Dampers
› Isolation
› Roller support conditions

Types of loading
› Blast
› Impact
› Live-load vibration

Combination cases
Ultimate loading simultaneously
› Extremely low probability
50% load simultaneously
› Will no longer be the dominate load case
Possible structural response
› More randomised vibration
› Combination of lateral drift and torsion
› Cancelled out

Wind
› Creates large base
overturning moment and base
shear
› Creates large amounts of
deflection in the wind
direction and also crosswind
due to vortex shredding
› Vortex shredding creates low
frequency of oscillation (may
not be the first mode)
› Requires stiff structure with
mass dampers
Seismic
› Creates large accelerations
of the structure
› Creates shear forces where
there is high weight (each
storey)
› Creates high frequency of
vibration throughout the
structure
› May cause resonance
› Requires ductile structure
with dampers at ground level
and throughout the structure

Current systems
History
Suitable systems
Criteria
Chosen systems
Optimisation
Final Design
Recommendations

Advances throughout history
Current systems for wind
› Structural Bracing system
› Dampers
 Tuned mass dampers
 Tuned liquid dampers
› Stiffness
› Aerodynamic shape
Current systems for seismic
› Stiffness
› Dampers
› Elevation control
› Plastic hinges
› Structural isolation

More than one lateral resistance
system
Most suitable systems based on
the previous criteria
Combined restraining systems
› Structural framing system
› Mass damping for serviceability
› Damping for vibration control
› Structural Isolation

To ensure most effective design
In depth study of lateral restraint
Proper testing (wind tunnel)
 Efficiency
› Functionality
› Constructability
› Materials
 Sustainability
 Aesthetics

Final designs consists of multiple systems.
Different methods of achieving combined lateral restraint
 Structural isolation coupled with stiff structure and
seismic dampers
 Flexible structure with seismic dampers and highly
designed tuned mass damper
 Extreme optimisation of aerodynamic shape and
seismic dampers

Related to this study
 There are a large amount of variables when designing
against lateral loading but will be presented once a
project comes into fruition
Related to lateral loading and response
 The site conditions play a key part in the lateral loading
and response
Related to lateral restraint systems
 Lateral bracing is almost unavoidable and therefore a
stiffness of a structure cannot be adapted. Therefore
dampers are more important form of vibration control
 A combined system although is highly possible and
feasible, may not be required due to likelihood of more
than on loading is dominate

 The understanding and mitigation of lateral loading is
vital for the design of any building
 A combined system if designed properly may
significantly reduce financial aspect
 Optimisation of the aerodynamic shape and the proper
use of dampers are the most useful when mitigating
lateral loading
 the possibility of the proper design and use of a
combined system in a high-rise structure to counteract
both wind and seismic is high and may be required in
areas where lateral loading cases are extreme

 RWDI Laboratories
 Structural Optimization by Gerald Kress und David Keller (June 2007)
 Earthquake Effects On Buildings by Christopher Arnold (2005)
 The Future Trend of Architectural Form and Structural System in High-Rise
Buildings by Matin Alaghmanda et al. (2014)
 Lateral bracing of Multi-Storey Structures by Kevin Torrie (April 1994)
 Wind Loading on Tall Buildings by P. Mendis et al. (2007)
 Full-Scale Dynamic Response of High-Rise Building to Lateral Loading by
James M. W. Brownjohn et al. (1998)

If you have any questions please contact me on:
jparkbench@hotmail.com
Or through

Jonathan park beb801 presentation 2016 sem 1

Recommended

Recommended

More Related Content

Similar to Jonathan park beb801 presentation 2016 sem 1

Similar to Jonathan park beb801 presentation 2016 sem 1 (20)

Recently uploaded

Recently uploaded (20)

Jonathan park beb801 presentation 2016 sem 1