design issues in tall buildings wind, seismic, loads, constructability issues and laws architecture engineering and legal

1. Reviewing the standards ,
issues & requirements for
Tall buildings
Sanjay R Srivastava
Architect Urban Planner

2. • Tuesday Oct 16th 1956…….
Frank Lloyd Wright unveiled a plan for
a mile high building.
• His dream was restricted by the
strength of materials.
• The "eighth wonder of the world" was
to be erected of steel and glass, with
floors extending outward from a
central core like branches from a tree
trunk.
• Wright’s design drew both jeers and
cheers.
but Wright insisted the structure was
"practical and expedient.”
62 yrs down the line we are yet to
complete this journey
Dreams

3. • However, Wright also acknowledged that construction
materials available at the time were inadequate for his vision.
• “But it’s certainly possible now,” says Joseph Colaco,
president of CBM Engineers in Houston and present here in
person amongst us.
• So what do Dr Colaco & his contemporaries like Dr Andy
Davids have that FLW didn’t?
• Well, to begin with, much better materials. The strongest
concrete available in the 1950’s could withstand compression
on the order of 21 megapascals, placing the ceiling on all-
concrete construction at roughly 20 stories.
• Better Seismic information, design methods substantiated by
research & learning's from practice and computing powers.

4. Since 1950’s Design methods for tall buildings have been
developed to cope with earthquakes in places such as California
and ……
Earth Quake & Wind
Tall buildings

5. …..along with the force of typhoons in cities such as Huston /
Hong Kong.
Effects of lateral loading due to wind on the building frame are
dramatically magnified for towers over about 60 storey, as
their slenderness increases.
For very tall buildings like the FLW’s mile high tower…. the
main issue for stability, is technology that can resist wind by
frames designed for loads & earthquakes.
Wind & Tall buildings

6. Let’s quickly try to touch base with these issues in
the Indian context

7. Indian codes
divide the sub
continent into 4
seismic zones.
Numbered
2,3,4,5
The darkest color
shows the place
of maximum
probability &
highest intensity
and is zone 5.
It is based on
extrapolation of
past events
EQ Zoning

8. 4.8
4.0
3.2
2.4
1.6
0.8
0.4
0.2
0.0
Peak Ground acceleration
in m/sec 2
This map shows the peak ground acceleration that can be expected basis past
history of Earth Quake events and other extrapolative tools
SHAKE MAP FOR INDIA

9. • The Indian codes relevant to these concern areas of
design are:
• Concrete: IS 456-2000 reaffirmed 2005 Plain and
Reinforced Concrete –
The method used in this code is ”Limit state of Design”.
• Steel IS: 800:2006 for normal and high strength steels,
• Light Gauge steel : IS :801 cold formed light gauge steel
• Steel Tubes : IS 806 for steel tubes .
Codes for earthquake and wind issues in
Tall Buildings

10. Types of cement
• Types of cement included in the revised IS : 456-2000 & available in
the market are as follows:
•Ordinary Portland Cement
33, 43, 53 grade (OPC), 53-S(Sleeper Cement)
•Portland Pozzolana Cement (PPC),
both Fly Ash & Calcined Clay based
• Rapid Hardening Portland Cement
• Portland Slag Cement (PSC) • Low Heat Portland Cement
• Sulphate Resisting Portland Cement (SRC) • Hydrophobic Cement
• Grades of concrete: included in the code from M10 to M80 are
readily available with reputed manufacturers
But what is really worth mentioning here is :
Ultra-High Performance Concrete or UHPC:
Cement & Concrete

11. • The ductile behavior of this material is a first for concrete, with the
capacity to deform and support flexural and tensile loads, even after initial cracking.
The use of this material for construction is simplified by the elimination of reinforcing
steel and the ability of the material to be virtually self placing or dry cast.
• Ultra-High Performance Concrete (UHPC), also known as reactive powder concrete
(RPC), is a high-strength, ductile material formulated by combining portland cement,
silica fume, quartz flour, fine silica sand, high-range water reducer, water, and steel
or organic fibers. The material provides compressive strengths up to 200 MPa (29000
psi) and flexural strengths up to 50 MPa (7000 psi).
• The materials are usually supplied in a three-component premix: powders (Portland
cement, silica fume, quartz flour, and fine silica sand) pre-blended in bulk-bags; super
plasticizers; and organic fibers.
• Superior durability characteristics are due to a combination of fine powders selected
for their grain size (maximum 600 micrometer) and chemical reactivity. The net
effect is a maximum compactness and a small, disconnected pore structure.
• It is yet to find a mention in IS : 456. Its manufacturing , mixing handling is yet to
be standardized. In short industry has moved ahead and is pulling away.

12. • Some of today’s tall
concrete structures,
such as the 88-story
(420-meter) Jin Mao
Tower by Skidmore
Owings & Merrill in
Shanghai, have been
built (1999) with this
type of concrete that
has a compression
strength greater than
130 MPa.

13. Fazlur R Khan’s systematic approach to structural frame
efficiency is still relevant to towers of Mumbai scale, where
the buildings are predominantly upto 60 floors and even
now striving to touch the 100 mark
The efficiency of the building frame has the greatest
influence on the embodied energy of a tall building.
He and his colleagues created a continuum of 4 typologies
depending on heights and structural systems for most
efficient use of materials
In the US, early development of steel led to its use as the
favored material for high-rise structures. In broad terms,
buildings could be divided into categories based on type of
structural system selected for the most efficient use of
material.
Steel & Tall buildings

14. Type 1 : Semi Rigid & Rigid Frame:
In broad terms, steel-framed
buildings with a rigid frame can be
economical for medium rise
buildings up to 20 storey;
IBM Plaza
Kansas

15. Type 2 : Frame with Shear Truss & Frame
with shear band & out rigger truss :
a vertical steel shear truss at the central
core of the building can be economical for
buildings up to 40 storey;
Frame
with Shear
Truss
Frame
with Shear
band and
out rigger
truss

16. Type 3 : End Channel framed tube with
shear truss or framed truss:
A combination of central vertical shear
trusses with horizontal outrigger trusses is
most suited for up to 60 storey
End Channel &
middle framed
truss
End Channel
framed tube with
interior shear
trusses

17. Type 4 : Rigid framed tubes,
Bundled tubes , Braced tubes:
For even taller buildings, it
becomes essential to transfer all
gravity loads to the exterior
frame to avoid overturning
effects. Rigid framed tubes,
bundled tube & braced tube
structures have been developed
to reach up to & over 100
storey in buildings such as the
Hancock and Sears towers in
Chicago.

18. Sears tower in Chicago is an example of
nine tubes framed to make a bundled
tube with belt and outrigger trusses.
The bundled tubes share common
interior side frames

19. Hancock Tower is tapered tube truss
system. It uses the principles of mega
structures. The cellular structure has
increased overall dimensions by using a
hollow open center framed tube at the
periphery. It is an example of transfer
all gravity loads to the exterior frame to
avoid overturning effects.
< ex. of Braced tubes & Rigid framed tubes

20. The relevant Indian Standards for Steel buildings and structural steel
are:
IS: 800:2006 for normal and high strength steels,
IS :801 cold formed light gauge steel & IS 806 for steel tubes .
Site welding is not recommended and bolting is preferred.
Steel, steel fiber and composites are is in many ways improving the
quality of concrete
“Additives like whisker-thin steel fibers are enhancing concrete’s
strength and rigidity,” says John Fernandez, a professor at MIT’s
interdisciplinary building-technology program. “We’re also seeing
research into smart fibers and carbon nano tubes that, when added to
concrete, will increase compression strength beyond 200 MPa.”
Fernandez’s work on smart fibers is also contributing to advances in so-
called high-performance concrete, which is strong but optimized for other
characteristics such as fire and blast resistance, vibration damping, and
durability

21. In the previous slides we have seen measures for stability for structural
loads & due to earth quake forces.
Another force impacting Stability & Design is wind.
Effects of lateral loading on the building frame are dramatically magnified
for towers over about 60 storey, as their slenderness increases.
Wind & Tall buildings
WORLD MAP of Tropical Storms

22. The relevant IS codes for design of wind loads is IS: 875 part 3
The code provides with mathematical modeling methods starting by stating
a) Basic winds speed for every town and a contour map plotting the entire
country into 6 wind speed zones these are 33, 39, 44, 47, 50, 55 m/sec.
b) Then it classifies by building type and height ..For tall buildings the factor k1 of
1.08 will be applicable.
c) And adjusts the model wind speed for Terrain quality ……. due to
inconsequential ht of building w.r.t to the tall structure the factor k2 will
always turn out to be 1.4. IF k3 stays at 1.0 then
d) The peak design wind speeds at 500 m from ground surface in India will vary
between 180 to 300 km per hour.
e) The code goes further to quantify through formulae wind load on Individual
members, wall and inclined roofs etc.
f) It points out that rough sea storms normally dissipate inland within 60 km of
shore line
g) Here is a compiled record of many storms for the sub continent.. Many storms
are seen ripping right into the sub continent sometimes more than 200 km.

23. This map shows the tracks of all Tropical cyclones which formed in the Indian
subcontinent from 1985 to 2005. The points show the locations of the storms at six-
hourly intervals and use the color scheme from the Saffir-Simpson Hurricane Scale.
Saffir-Simpson Hurricane
Scale
TD = Tropical disturbance TS= Tropical Storm

24. 1998
1996
1999
1997
The North Indian cyclone season has no official bounds, but cyclones tend to form
between April and December, with peaks in May and November.
This basin is divided into two different seas by India; the Arabian Sea to the west,
abbreviated ARB , and the Bay of Bengal to the east, abbreviated BOB by the IMD. On
an average, about 4 to 6 storms form in this basin every season.
CYCLONE SEASON SUMMARY

25. Year 2010 CYCLONE SEASON SUMMARY map for the North Indian Ocean
First date the North
Indian Ocean storm
formed
May 17, 2010
Last storm
dissipated
December 8, 2010
Strongest storm Giri – 950 hPa (mbar), 195 km/h (120 mph) (3-minute sustained)
Depressions 8
Deep depressions 6
Cyclonic storms 5
Severe cyclonic
storms
4
Very severe cyclonic
storms
2
Super cyclonic
storms
0
Total fatalities 402
Total damage At least $2.985 billion (2010 USD)

26. Year 2007 GONU CYCLONE
First date the North
Indian Ocean storm
formed
June 1, 2007
Last storm
dissipated
June 7, 2007
Strongest storm Giri – 920 hPa (mbar), 270 km/h (165 mph) (1-minute sustained)
Depressions 8
Deep depressions 6
Cyclonic storms 5
Severe cyclonic
storms
4
Very severe cyclonic
storms
2
Super cyclonic
storms
0
78 and 37 missing 402
Total damage At least $4.4billion (2007 USD)
GONU 270 km/h (165 mph))

27. • Tall buildings, today , are an inevitable building form. They are
a part of the contemporary landscape. New design ideas are
becoming common currency among progressive architects and
developers.
• “Bioclimatic skyscrapers” and well-designed tall buildings can
be energy efficient and closely relate to their site.
• New buildings are increasingly user-friendly, offering a
comfortable occupant-controlled environment all year. The
creation of internal green “sky gardens” within buildings
contributes to the natural environment.
ENERGY

28. In this context, Europe’s tallest building,
the Commerzbank building in Frankfurt,
stands out.
To reduce energy consumption, all
offices have natural ventilation and
opening windows.
It succeeds to an extent in creating a
pleasant and energy efficient working
environment.
Generous sky gardens spiral up the
tower, and act as a visual and social
focus for clusters of offices.

29. A mile-high skyscraper should be more energy efficient than existing
structures, which together already consume about one-third of the world’s
generating capacity.
”With an integrated approach to the building envelope and the
mechanical and electrical systems, we can significantly reduce energy
consumption with little difference in construction costs,” says Spiro
Pollalis, a professor at Harvard University’s Graduate School of Design.
He envisions that photovoltaic panels along the length of the immense
towers, along with strategically placed windmills and double-layer facades
that act as giant heat sinks, will provide enough juice to power elevators and
lights as well as heating, ventilation, and air conditioning systems.
”The ultimate aim is creating buildings with zero net energy use,” says Mir
M. Ali, a professor of architecture at the University of Illinois at Urbana-
Champaign and member of the international Council on Tall Buildings and
Urban Habitat.
Several skyscrapers under construction, including the Pearl River Tower in
Guangzhou, China, are employing new technologies to avoid using any
energy from the grid.

30. “Structural engineering solutions must be
integrated with the architectural and
sustainable engineering designs so that they are
inseparable,” said Bill Baker, SOM structural
engineering partner. “It is the collaboration
between our structural engineering, architecture
and sustainable engineering practices that allow a
building such as Pearl River Tower to become
reality.”

31. Embodied Energy
Buildings not only use energy, it takes energy to make them. This is “embodied”
energy, which is all the energy required to extract, manufacture and transport a
building’s materials as well as that required to assemble and “finish” it.
As buildings become increasingly energy-efficient, so the energy required to
create them becomes proportionately more significant in relation to that required
to run them. This is particularly true because some modern materials, such as
aluminum, consume vast amounts of energy in their manufacture.
The most common building material with least embodied energy is wood. Timber
is regarded as the greenest building material. However, deforestation of the
planet is also one of the gravest environmental issues and only wood used from
sustainably-managed forests is truly green.
Brick is the material with the next lowest amount of embodied energy, followed
by concrete, plastic, glass, steel and aluminum.
A building with a high proportion of aluminum components can hardly be green
when considered from the perspective of total lifecycle costing, no matter how
energy-efficient it may be.

32. Taipei 101
Combination of previous systems
are used to design new systems.
Lateral resistance to drift and
acceleration are overriding
concerns.
This makes damping an important
issue.
At acceleration beyond 25 milli-g
human discomfort begins.
Tuned mass damper help control
sway

33. Strength and flexibility for TAIPEI 101
is achieved through the use of high-
performance steel construction.
Thirty-six columns support Taipei 101,
including eight "mega-columns"
packed with 10,000 psi (69 MPa)
concrete. Every eight floors, outrigger
trusses connect the columns in the
building's core to those on the
exterior.
The foundation is reinforced by 380
piles driven 80 m (262 ft) into the
ground, extending as far as 30 m
(98 ft) into the bedrock.
Each pile is 1.5 m (5 ft) in diameter
and can bear a load of 1,000–
1,320 ton .
Facade system is therefore able to
withstand up to 95mm of seismic
lateral displacements without
damage.

34. A 660 ton, 18 ft dia. steel pendulum that serves as a tuned mass damper, (US$4 million )
is suspended from the 92nd to the 87th floor, it sways to offset movements in the
building caused by strong gusts. It can reduce up to 40% of the tower's movements . Two
tuned mass dampers, each weighing 6 ton sit at the tip of the spire.

35. • Efficiencies in the design and construction of Tall buildings can make a
significant difference both economically and environmentally.
• Engineers strive to find savings in materials through efficient design,
making best use of concrete and steel in floors and structural frames. The
environmental impact of their decisions is not always clearly understood.
• New methods and software packages are being developed to clarify the
burdens on land, air and water resources.
• Integrated design and the use of structural materials for optimum
performance in controlling the internal environment of buildings can
provide added benefits at no extra cost.
• At the same time selection of façade materials, governed largely by
architects, can greatly influence the thermal performance of buildings.
• As methodologies for the life cycle assessment of cladding materials
develop, awareness is growing of their environmental impact among
designers.
• The choice of materials for architectural finishes should now be made with
improved understanding of their relative merits in sustainable terms.
SUMMING UP

36. Thank you for your patience
Acknowledgements:
Dr Nitin Dindorkar Professor Maulana Azad National Institute of Technology Bhopal for his
guidance and finding the time to advise
Dr P Jayachandra : Tall buildings … Preliminary Design & Optimization
USGS for its web based images and documents explaining concepts
Wikipedia ,You Tube, Google Search for various photographs and web based information
placed in the public domain made available through their servers
All architects and developers whose projects have been referenced here as there were so
discharged in the public domain for reference.