CE4670 CASE STUDIES
GROUP 7
CE18B024- ROHIT B
CE19B009-G SARAYU
CE19B056-JURAIJ
CE19B065-MANIKANDAN
CE19B107-GURUCHARAN
TABLE OF
CONTENTS
Introduction, Architecture and Geography
Construction Plan
Foundation
Super Structure
Observatory Deck, Pinnacle
Wind Modelling and Seismic
Structural health monitoring
Comparison with other structures
GENERAL DETAILS
Jeddah Tower previously known as Kingdom Tower, is a skyscraper
construction project currently on hold. Located on the north side of Jeddah,
Saudi Arabia,
Architecture Style: Neo Futurism
Architecture: Adrian Smith+Gordon Gill Architecture
Structural Engineering : Thornton Thomasetti,Magnussen Klemenicic Associate
Developer: Jeddah Economic City
Construction Contractor: Saudi BinLadin Group
Estimated Budget : 1.23 Billion USD
Construction Started: 1 April 2013
HOW HIGH CAN WE CONSTRUCT?
SKY SCRAPPER WITHOUT COLUMN
This tower is going to be the first tower to reach 1 Km milestone
This tower is constructed to enhance the tourism industry in Saudi
Arabia. As a state of an art project of Jeddah Economic City
To be more slender, stiffer, and taller it is constructed using
Reinforced Concrete
After construction, it will be the world's tallest building
Introduction
It's shape is inspired by a bundle of leaves shooting up from the ground and it has
been designed on Y shaped plan .
its structure is reinforced concrete frame almost entirely made of reinforced
concrete shear walls,coupling beams & reinforced concrete slabs
Geography
Tower is located in coastal plain of
red sea .
Due to coastal influence there will
be salt content in the wind , need to
consider rust resistance
region is deserted area with sandy
soil -relatively low strength.
soil is silty sand type in desert , pile
foundation and raft are used .
Geography and environment condition
need to design in a way in which wind forces
are less.
jeddah is lying on tropic of cancer usually
have high temperature on day throughout
year
In winter temperature will reduce 10 C . while
construction needs proper control of
temperature to reduce shrinkage and cracks .
also need to consider expansion of concrete
due to high temperature .
Architecture
The Tower has a tapered Y shape at the base
with an angle 120 degrees extending 12
hectares with three wings terminating at
different heights .
The tower is continuously Tapering as the
tower ascends to the top, And the tower has
an aspect ratio of 12:1, which is the highest
for any man-made structure in the world.
Architecture
The architectural style for the tower is Neo Futurism, which is to
make unconventional building shapes, prioritizing modern aesthetics.
It aims to have a more continuous surface.
It promotes the use of new materials like glass, aluminum, and steel
to make the structure look more slender, and the reflecting ability of
the building is also considered for the design.
Architecture
Another major attraction of the structure is the
observatory desk, Once completed it will be the
deck located at the highest elevation in the World
Which is at level 157 at an elevation of 630
meters, apart from the large sky desk, small
terrace connecting two wings are provided to
increase the terrace area, also to help cleaning
the external surface.
Architecture
Figure shows the usage of different
parts of the tower in which the majority
of the part is residential
the Bottom part is reserved for the
hotel and office to maximize the floor
area for it, and Executive suites and
penthouses are reserved for the
business class and the royal family.
Height of each floor level is only 4 m
Construction
Reached at 260 m height and 45% concrete is placed until now
Design ideology is to use concrete till maximum height possible, for this
purpose special concrete boom pump is used
Tower Jump formwork is used for the construction
First the walls are constructed then the slabs are constructed
later
To avoid differential heating in the concrete soon after placing
insulation is provided
To control heat developement due to concrete placing, and to prevent
evaporation frozen ice water is used in concrete mix
FOUNDATION DESIGN
1008 m tall reinforced concrete
structure
No individual columns
Load bearing wall-slab system
Varying loads:
50 MN for centre walls
400 MN for wing end walls
FOUNDATION DESIGN
Raft foundation chosen :
Poor soil conditions
Even load distribution
Area = 3720 m2
Depth: 4.75 m average
Gravity load:
Superstructure: 8428 MN
Raft: 416 MN
Total: 8844 MN
FOUNDATION DESIGN
Subgrade pressure below raft = 8844 MN/3720 m2 = 2.38 MPa
GEOLOGIC SETTING
Project along Red Sea coastal plain
Aeolian sand deposits on surface
Underlain by coraline limestone
Pockets of clay or silty sand
Shells, salts and gypsum deposits
SUBSURFACE CONDITIONS
Project at underdevoloped location
Seven Borings(3x120m, 3x150 m,
1x200m)
In-situ tests:
Groundwater observation wells
Pressuremetre tests
P-S suspension logging(Wave
velocity)
Groundwater level on par with Red Sea.
SUBSURFACE CONDITIONS
Laboratory tests for rock:
Density
Water content
Point load test
Unconfined compressive strength
CD Triaxial test
Repetitive Triaxial tests
OBSERVATIONS
OBSERVATIONS
INFERENCE
45 metre deep Coralline Limestone
Porous, 1.8 specific gravity
1.5-2.5 MPa UCS, too close to 2.38 MPa
So Raft soundation alone not sufficient
Bored Pile-Raft Foundation chosen
Angular gravel layer can affect pile stability
FULL SCALE PILE LOAD TEST
Load tests for following configurations:
Bored pile(Circular)
Barrette pile (Rectangular)
1.5 m square footing
Bentonite slurry and polymer stabilisers
Measured:
Unit skin friction
Load-settlement behavior
OBSERVATIONS
OBSERVATIONS
OBSERVATIONS
INFERENCE
Test data gives:
Allowable bearing capacity
Modulus of deformation
Poor result:
Mineral slurry
Barrette pile
Most suitable:
Circular bored pile
Natural slurry for shallow foundation
Polymer slurry for deep foundation
FINITE ELEMENT ANALYSIS
Six distinct layers
Grouped by Engineering properties
Stiffness data from:
Lab tests
P-S logging test
Full-scale load test
Upper and lower limits for
response/stiffness
ASSUMPTIONS OF FEM MODEL
270 bored piles in Raft-pile foundation
Raft modeled as solid tetrahedral elements
Elastic modulus of each element = 36.7 MPa
Mohr-Coulomb model for Coralline layer
Elastic model for other layers
Horizontal stratification assumed
Beam elements to model pile behavior
Negligible tip bearing capacity
ASSUMPTIONS OF FEM MODEL
Sta
Piles upto 45 m depth dug with natural slurry
Remainder with polymer slurry
300x300x200 m box model
Loads as pressure tips on top of Raft.
Stages of subsurface settlement:
1) Self weight
2) Due to pile+raft
3) Due to superstructure
Iterative procedure between structural and subsurface model
INITIAL DESIGN
Assuming equal pile depths,
Load carried by each pile = 8844/270
= 33 MN
45 m piles found suitable
Center to edge differential
settlement = 173 - 108 = 65 mm
But further iterations show higher
loads on foundation wings
1:900 angular rotation
FINAL DESIGN
Pile dimensions:
226x1.5 m piles
44x1.8 m piles
Varying pile depth:
45 m at wings
105 m at center
Natural slurry piles avoid
gravel zone
INITIAL SETTLEMENT ESTIMATE
CONVERGED ESTIMATE
PILE HEAD AXIAL LOAD ESTIMATE
FINAL DESIGN
Center pile 5 m above sandstone layer
Differential settlement = 108 - 86
= 22 mm
Significantly below initial design (65
mm)
1:2000 angular rotation
Better load distribution
BEARING PRESSURE ON ROCK
Maximum pressure = 625 Kpa
Below raft wings and center of raft
UCS of corraline rock = 1.5 MPa atleast
Factor of safety = 1500/625 = 2.4
LOAD SHARING
Pile head loads:
1.5 m pile: 18 ~ 29 MN
1.8 m pile: 24 ~ 38 MN
75% superstructure load taken by piles
25% by rock subgrade below raft
Super Structure
There are no columns in the tower!
This tower has a bearing wall system
Shear wall is the only vertical load transfer element, Which is
continuous from foundation to top without joints.
There are no outriggers to transfer lateral load from exterior to core.
The loads are carried to the foundation directly, because the structure
stiff on all part of structure.
There are no spandrel beams in the tower
Super Structure
To connect shear walls Coupling beams are provided.
Slabs are supported on the load bearing wall
Super Structure
Why shear walls and no Columns?
Shear walls are stiffer than the columns since the selfweight is more
than the columns
Shear wall can bear lateral loads better than the columns can
only transfer compression loads mainly.
Using shear wall will make the structure more efficient in size as
compared to the group of columns that can bear same load
Make structure more slender
As a disadvantage shear wall reduce the effective usage space
And have lower axial load capacity than column
Super Structure
Load Bearing wall
Inner Triangular core walls
These Triangular Inner core provides High Torsional Stiffness to the tower
Wall is nearly solid and have only very few openings
This wall extend from the foundation to the top
Lift systems are provided in the central region
These walls are 800mm thick at the base
Super Structure
Load Bearing wall
Corridor walls
These walls are the second most highly stressed due to the
openings in the walls
At the openings, these walls are connected using 1.6 m deep
single span coupling beams
These openings are considered as critical locations
in the design
These walls are 1m thick at the base
Super Structure
Load Bearing wall
Transverse fin walls
These walls are the highly stressed part of the tower.
There are no openings in the wall,but the length is less
Two fin walls on opposite sides of the stair walls are connected by three
span coupling beam
These walls are 1.2 m thick at the base
Super Structure
Load Bearing wall
Wing End walls
These walls are the stabilizers to the tower against lateral loads
These are highly stiff element, Very few openings, since shear wall have
extra thickness to provide fire resistance to emergency stair ways
These are the walls at end of the wings of tower
These walls drops off as the tower taper
These walls are 850 mm thick at the base
These walls are connected to corridor walls by
1.5 m thick coupling beam at base
Super Structure
Coupling Beams
Coupling beams are provided to connect between the shear walls
inorder to distributer loads within system.
Coupling beam will increase lateral load bearing capacity.
Decrease overturning effect and increase overall Stiffness of the tower
Materials used
High Strength Self Consolidating Concrete is
used for construction
For Rebaring due to heavy reinforcement
steel plates are used
Due to late strength developement of High
Strength Concrete Tested strength is higher
than planned
End walls sloping geometry
The three walls rise at a
constant incline.
Three slightly different
anngles for each of them.
Different elevations and
distinctive top of the
tower.
Tower + Spire
Aspect ratio : 12:1
But how do we measure it?
The top views of the tower
bearing wall and that of the
upper 1/3rd of the tower are not
same
End walls come closer and closer
and forms the walls of the spire.
Top 50m of the tower- concrete silo
No transfer of the load.
This graph explains axial load stress behaviour versus time
We can get any behavioural and strength related topic through
this graph.
Observatory deck
Jeddah Tower will have the highest
observatory deck and hanging
balcony, about 652 meters above the
sea level.
Core of the project
The deck occupying 500 sq.ft has a
bird's eye view of the Red sea
This oservatory deck can be assumed
as a cantilever structure.
Skyraft
Its provided above which the
closed silo is constructed
It has a thickness of 4 meter
Facade
The smooth, tilted façade of Jeddah Tower
generates a helpful effect known as wind vortex
shedding
When wind coils around the edge of a building,
rushing in to enter the low-pressure area,
vortices form, causing the structure to wobble
from side to side due to velocity and pressure
changes.
The facade features low conductivity glass to
beat Jeddah’s high temperatures.
World’s largest LED screen to be integrated into
this facade.
Seismic Modelling
Tower is constructed in Low Moderate Earthquake Prone area in Saudi
Arabia
It is conservative according to Saudi Building Code (SBC301)
This tower belong to site class B acccording to code
They have Conducted site Specific Hazard Analysis
Wind is considered as more critical than earthquake for the design of
the tower
Due to presence of shear wall it imrove the stiffness and the mass.
Wind Modelling
50 Year return wind speed for 3 sec is considered as 42.2 m/s and
the severe wind load that experienced on Jeddah is 34.8 m/s
Wind tunnel tests by scale modelliing is done
Due to Y legged shape continous tapering reduce the formation of
vortex around structure
Inorder to predict the exact variation of wind above 600 m
certain tests are done
Historical Surface wind Record
Air Balloon Sounding
Wethear Research Forecast model
Wind Modelling
High Frequency Force Balance (HFFB)-1:800 scale Model which is to
measure forces at base in Early stage analysis-Rigid model
High Frequency Pressure Integration(HFPI)-1:600 scale model to
measure effect of pressure at the base
HFPI- 1:400 Model for just the Spire, Half model becuase in previous
test the tower is very thin
Aero Elastic Model - 1:600 scale model- scaled every properties
Design is done by considering the worst case scenario of all the tests
Dampers
Tuned mass dampers are provided on the top closed
spire since the wind is very high above 650 m
Similarly Tuned mass dampers are provided for the
observatory sky deck
Structural Health Monitoring
Since this is a state of art project, immense study, care, and evaluation are
needed to assure the quality of structure, material, and the components
used.
Various procedures are given to monitor structure in the short term
during construction and in the long term to take care of all details of
motion.
By using the feedback after the construction of the tower we can measure
the deflection and behavior of the real structure to improvise the design
condition of the scaled model and mathematical model.
Structural Health Monitoring
For PIles
Pile testing is done by pile loading to measure settlement and stress at
the base of the pile after the construction.
Measuring devices are embedded in the pile to measure the details.
Also, the above details should be measured periodically in months
during the construction so that everything is in control, to ensure no
settlement more than the limit.
For Raft
Concrete behavior details like differential temperature development in
the core and surface and strength developed to measure these concrete
cube of 4.5 meters, are required to measure long term hydration and
heating are under control for the real raft.
Structural Health Monitoring
Also, load cells are provided on each wing and central part to make sure
the stress developed is within the limit.
For overall pile and raft foundation settlement data is collected to check
whether it's under limit during the period of construction and after it too.
To ensure Verticality and vertical deformation
To ensure the verticality, survey equipment at the level of the raft at
different locations and make sure it exactly is defined as per plan during
each stage of construction.
Also, vertical shortening due to elastic, creep and shrinkage strain is
measured as a relative change in height of the floor with respect to the
assumed origin.
It is measured after the construction and during construction.
Structural Health Monitoring
To ensure horizontal shortening and tapering of the tower
As the height increases the tower size is tapered continuously so the change in
height should be made sure while making the formwork it should be done by
surveying with respect to the well-established origin.
To measure horizontal deflection due to elastic, creepage, and shrinkage shortening
strain is also done by surveying.
Wall Stress
Here measure the stress developed due to loading by strain gauge at various
locations to measure the stress indirectly check this during the construction and
after it and make sure it falls below the limit.
Structural Health Monitoring
Steel spire
The top part of the tower is made of steel, and its connection is made of
welding, so it should be inspected thoroughly before and after welding
whether it's perfect or not, to avoid sudden brittle failure(lamellar
Tearing).
What should the owner do?
Hire a third party to ensure that the plan is ok and every work is done
according to the plan for better inspection.
After the construction, the owner should compare the results of FEM, the
physical model, and the real structure to make sure that the different
limits for stress and load are not exceeded or not. These can be
considered as the acceptance criteria
Structural Health Monitoring
Conduct routine checkups for all structural elements, crack development
in concrete checks for the cause and do remedial measures.
Life of the Structure
As per the plan, the life of the structure is 100 years, as per the plan
which is conservative. So during each month the environment and the
corresponding changes, deflection, and measurements are fed to the
Finite Element Model to mimic the structure and can predict how much
more the structure can be sustained.
Comparison with Burj khalifa
Comparison with Burj khalifa
Both Structures have Neo-Futurism architectural style
Jeddah Tower
Lloca
Potential Tallest building
with height ~ 1 Km
Will consist of 167 floors
Preliminary cost - 1.23
billion USD
Located in Jeddah, Saudi
Arabia.
Burj Khalifa
Loa
Tallest man-made free-standing
structure with height 829.8m
It consists of 163 stories
The total construction cost was
$1.5 billion USD
Located in Dubai, United Arab
Emirates.
Comparison with Burj khalifa
Jeddah Tower
Lloca
Burj Khalifa
Loa605 m
Top floor height - 668m
Aspect ratio - 12:1
Contains no column
Tower tapers Continously
Slab thickness of 250 mm
Estimated to use 80,000
tonnes of steel
Top floor height - 605m
Aspect ratio - 9:1
Contain super cylinder column at
the wing end
Tower tapers at specific location
330,000 m3 of concrete and
39,000 tonnes of steel were used
Comparison with Burj khalifa
References
https://global.ctbuh.org/resources/papers/download/20-case-study-kingdomtower-jeddah.pdf
https://global.ctbuh.org/resources/papers/download/2384-case-study-kingdomtower-jeddah.pdf
https://global.ctbuh.org/resources/papers/download/20-case-study-kingdomtower-jeddah.pdf
https://global.ctbuh.org/resources/papers/download/2387-from-supertall-tomegatall-analysis-and-design-of-the-kingdom-tower-piled-raft.pdf
https://global.ctbuh.org/resources/papers/download/2900-saudi-arabia-jeddahcity-and-jeddah-tower.pdf
https://www.youtube.com/watch?v=GJLjjTfJjWQ
THANK
YOU