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BACHELOR IN QUANTITY SURVEYING
Report Assignment
Name: Liew Yong Sheng 0315108
Davin Young Qiao Wei 0321065
Wong Geng Sen 0321690
Tay Sy Min 0320813
Kevin lee hee xian 0315192
Lecturer: Ms.Azrina
Subject: Construction Technology
Abstract
The purpose of the project is to analyse and understand the horizontal
structural elements of The Gardens Mall starting from Foundation, Slab and
finally Roof by first analysing the nature of the building and its environment.
Through research, the report also compile the possibility of substituting the
elements used with recommendations to explore the possibilities and result of
the usage of these elements by research and reasonable deduction alone.
Table of Content
Introduction 1
Part I: Visualization 2
Part II: Analysis
- Foundation
- Slab
- Roof
4
Part III: Recommendation
- Foundation
- Slab
- Roof
13
Conclusion 22
Appendix 23
References 28
Introduction
Within the hearts of Mid Valley City stood The Gardens Mall. Along with Mid Valley
Megamall, The Gardens Mall is 816,657 sq. ft. of let net lettable retail space and retail
tenants at 31st March 2012 and 8 storey height. The entire building are divided into eight
floors starting from the LG floor to 6th floor containing 200 outlets for fashions, food and
beverages, jewellery and time pieces and etc. Parking zone are divided to four lower floors
after lower ground floor from P1 to P4 under Zone B.
The Gardens Mall was built as a single mall with department stores anchoring on both ends
in symmetry. The Gardens Mall is a premium fashion mall and targets the upper-middle to
upper income families and relegate in nearby affluent residential area such as Seputeh,
Bangsar, Taman Desa and so on. Being connected to Mid Valley Megamall which is
connected to the KTM station, The Gardens Mall also gained traffic as high as Mid Valley
Megamall making The Gardens Mall a success among nobles.
The Gardens Mall, built after and also opposite of Mid Valley Megamall in Mid Valley City, is
surrounded by roads including Jalan Maarof, with Sungai Klang at the side, and Lingkaran
Syed Putra. Here we can deduce the soil condition around the area during the construction
of The Gardens Mall was considered man-made because of how close it is to Mid Valley
Megamall and Jalan Maarof. However, the soil condition within the area itself could be
deduced to be less suitable for construction. The deduction was made due to Sungai Klang
beside Jalan Maarof where the soil in underground level was more moisturized to be stable.
Part I: VISUALIZATION
Part II: ANALYSIS
Foundation
Foundation is required to transmit all the dead, superimposed, and wind load from a
building to soil on which the building rest. The choice of foundation used depends to a large
extent upon their properties relative to the environmental requirement of the building and
the strength property of which the foundation used.
To deduce the foundation used, we will need to first analyse the surrounding of The
Gardens Mall and it’s construction history. As mentioned in the introduction above,
Figure 2.1 Suitability of
foundation types to
various soil
The Gardens Mall, during its construction, are surrounded by man-made soil as could be
seen in the map in Part I. However, the soil on The Gardens Mall itself would be deduced to
be unsuitable for construction based on the Sungai Klang’s water moisturizing the soil of The
Gardens Mall even after the construction of Mid Valley Megamall.
Based on this figure, it is highly likely the soil used for The Gardens Mall was soft silt clay.
With this, we believe that if the wrong foundation is used, subsidence would occur. Next to
consider in choice of foundation would be plan and height of the building, The Gardens Mall
is a tall building consisting eight floors and four basement with the area of 800 thousand
sq.ft.
Through these analysis, we have come to a conclusion of the engineer’s choice of
foundation: Raft Foundation. Raft foundation consist of a raft of reinforced concrete under
the whole area of a building. Normally it is used when there are no firm bearing strata of soil
exists at reasonable depth below surface.
Figure 2.2 Sample of a raft
foundation
Usually supported by a compacted hardcore base which extends beyond the edge of the
raft. In order to allow the outer leaf of the wall to continue below reduced level, the edge of
the raft is stepped.
There are benefits when using raft foundation. Technically speaking, it is quicker to
construct and a lot faster to complete because it avoid planking and strutting in a self-
supporting soil as compared to conventional strip footing. In comparison to other
foundation, raft doesn’t need a deep excavation. This makes the project as large as The
Gardens Mall a lot more economic.
Slab
Slab is, by definition, a horizontal plane that is supported by vertical columns if suspended
that which consolidates and stable enough to bear dead and life load. Based on observation
alone (see appendix), we have come to a conclusion of the slab used would be a two way
slab.
Two way slab is a slab supported by 4 beams of 2 different directions, usually in ratio of
longer span to shorter span that is less than 2. The reinforcement bar are placed parallel to
the beams in two direction as well to ensure loads are distributed equally. By concept, the
loads are supported in two direction.
Figure 2.3 and 2.4 shows Two Way Concrete Slab with
labels and description
Two way concrete slab is generally more economic because of its large effective depth. It is
also best used when there is possibility of shear forced because the structure holds relative
ease with its beams could be reinforced against these forces. In addition, it provides great
amount of lateral stiffness due to the presence of beam and efficiency of beam-column
connection. However, the complexity of reinforced bar and formwork increases its
production price which would prove slight disadvantage of using this structure though we
should also remember that The Gardens Mall’s budget was supported with Mid Valley City’s
profit.
Roof
Regardless of the purpose of the building, be it commercial or industrial, roof is required.
There are several types of roofs in the building industry but all serve the same functions
which are:
1. To provide shelter for weather such rain, wind, snow and dust
2. To prevent excessive heat loss during winter
3. To keep the interior of the building cool in the summer.
4. Designed to accommodate all stresses encountered especially strong winds.
5. Designed to accept movement due to changes in temperature and moisture
content.
6. To provide lateral restraint and stability to adjacent walls
7. To resist penetration of fire and spread of flame from external sources
And also a few factors to consider when choosing the type of roof:
1. The size and shape
2. Aesthetic appearance
3. Economy
4. Function of Building
Gambrel Roof
A Gambrel roof is usually, as defined by Harper and Douglas in Online Etymology Dictionary, a
symmetrical two-sided roof with two slopes on each side. The upper slope is positioned at a
shallow angle while the lower slope is steep. In this case however, The Gardens Mall opted
to use half gambrel roof.
Figure 2.5: Bird view ofThe Gardens
Mall.
Figure 2.6: view from inside - One sided gambrel roof Figure 2.7: view form inside - Dome roof
The Gardens Mall adapted the gambrel roof system. The Gardens Mall is placed in an area
which encounters with storms and strong winds very frequent throughout the year
especially during monsoon seasons, this is why gambrel roof is used mainly to withstand this
kind of weather. According to one of the contractor’s document by Henry Butcher Malaysia,
the roof consist of weather-proof finishes as well to provide maximum immunity against the
bad weather of Kuala Lumpur.
Figure 2.8 Effect of win on buildings
Besides, it is also quite clear that this type of roof was chosen for its aesthetic qualities.
Gambrel roof requires very little frames for support therefore providing the architect with
more and better options when designing the building. Hence, with the right finishes and
some high order designing, it can look very appealing from the inside especially for
commercial buildings such as malls.
A roof truss serves the same function as the beam of a slab. It consists a series of separate
members instead of a continuous plate. A roof truss supports the load of the roof while a
beam, similarly, supports the load of a building. In a truss, the lower horizontal part and the
upper horizontal part provides support and carries tension and compression of the roof.
According to Henry Butcher Malaysia, a portion of the roof was constructed with steel
trusses covered with glass panel. The type of roof truss used here is Warren trusses and it’s
made up of mild steel. Warren trusses have inclined web members are sometimes
introduced to reduce panel length of the top cord which is compression.
Figure 2.9 shows the trusses used in The Gardens
Mall
Figure 2.10 shows a simple figure of a truss
Steel roof trusses are mainly used for industrial or recreational purpose. A steel truss is a
plane frame consisting of a series of rigid triangles composed of a compression and tension
members. The compression members are called rafters and struts, whereas the tension
members are termed ties. According to “Construction Technology 2” by R. Chudley, Standard
mild steel angles with the recommendations of BS 4848 are commonly used as the
structural members and these are connected together, where the centre lines converge
with flat shaped plates are called gussets.
A few disadvantages that needs to be considered when using Gambrel Roof is that it have
very poor ventilation. It requires a specifically designed ventilating system by engineers to
increase better performance in ventilation. This means that Gambrel Roof will be costly in
its maintenance including the consideration of its height in The Gardens Mall.
Dome
A Dome is an element in architecture that resembles the hollow upper half of a sphere.
Pantheon in Rome, Italy was the first to use the structure of Dome back in 27 BC during the
reign of Augustus Caesar. In later years, many building in Islamic region adopted this type of
roof to encounter hot weather in the Middle East.
Historically, domes were constructed using mud-brick and then baked brick and stone were
introduced in later stages. In modern times, with more building materials and better
understanding in laws of physics in structures, methods of construction have changed.
Bricks and blockes are now replaced with iron and steel beams, cables and pre-stressed
concrete which eliminates the use of external buttressing and made thinner domes possible.
The light weightiness in modern domes not only allow greater spans but also allow the
construction of moveable domes for modern sports stadium.
Similar to the gambrel roof, The Gardens Mall also uses Dome roof to improve the overall
appearance of the mall. As illustrated in the picture below, the bottom part of the dome
roof consist of reinforced block in my opinion and it is layered in English bond which is very
pleasant to look at. The
layer above the blocks is
timber followed by marble
and then the top is a glass
window
The strong and durable
structure is also a perfect
defence against storm just like the gambrel roof mentioned
before.
Besides that, the dome roof also provides a more cooling surrounding inside the building as
it has good air circulating properties. This is extremely advantageous to a hot and humid city
such as Kuala Lumpur. Thus, making the building more environmental in subject of air
conditioning as well as economical in its energy saving and also low cost in maintenance and
construction depending on the type of material used.
Figure 2.11 - Traditional construction of a dome roof
where bricka nd block were used
Figure 2.12 - Traditional construction of a dome roof
where bricka nd block were used
Figure 2.13 shows the dome used in The Gardens
Mall
However, if not done wisely, dome are more prone to material wastage. Geodesic dome,
which is a high likely method in dome construction in The Gardens Mall, has less surface
than a conventional structure, nonetheless cutting triangles from sheet material is very
uneconomical unless material of which the dome is built is carefully chosen.
Unlike the gambrel roof, the dome roof do not require any trusses frame nor joists for
support. However, if the dome structure is large then it requires trusses and framing. For
example, the Civic Arena in Pittsburgh, Pennsylvania adopts the dome roof and has trusses
to support it.
Figure 2.13- Civic Arena
Figure 2.14- Truss on Civic Arena
Part III: RECOMMENDATION
Foundation
1. Pad Footing]
Pad footing is a shallow foundation that is usually used to support individual or multiple
columns, spreading the loads to the ground below. Unlike raft or strip foundation, pad
foundation do not run around the building but rather as a single point around the
building. Like strip foundation, its thickness is governed by reasonably strong subsoil
exists near surface of ground or at the level of proposed basement floor.
Figure 3.1 Pad Footing
However, the possibility of using Pad Footing
instead of Raft Foundation is deemed to near
impossible because Pad Footing cannot take
excessive weight. The Gardens Mall holds a
load worth eight floors. For this to work, the
soil is required to be stiff such that mall would
not subside which, as discussed earlier, was
not the case. Despite being surrounded by man-made soil environment, pad footing is
still weak against differential settlement. This means that if this foundation is used for
the Mall with its dimension remained, the mall would suffer severe cracks and
eventually would crumble down.
In order to avoid the damages, deep excavation is needed which will increase labour
work and price of construction. Not to mention such a technique is not economic.
Henceforth, it is near impossible for the engineers to choose this foundation for the
mall.
2. Pile Foundation
Figure 3.2 Pad footing of a house
Pile Foundation are thin columns of
reinforced concrete that transmit the
load deeper into the subsoil where
material that are dense could be found
to prevent collapse or uplift or by
friction between soil or a combination
of both.
Through thorough consideration, there is a debate subject to either pile foundation or raft
foundation. By the end of the day, we have concluded that raft is a more suitable
foundation mainly because it is costly with unworthy cause. First of all, construction such as
this would require heavy equipment for handling. Boring piles into deep soil would take
more labour for the construction. Second, the exact length required at the side could hardly
be determined in advance. Along with the problematic dimensional stability of the ground
as an issue.
It is suggested in Mitchell’s Structure and Fabric Part 1 6th Edition that piles can be easily
formed by boring in firm soil. This pile is known as short bore pile foundation. This pile is
usually used in shrinkable clays and reduce the amount of excavated soil when the pile is
bored over trench and strip. It is faster to construct and can work in any weather.
However, we find a few probably rather similar to the general pile foundation. Like pile
foundation, short bore pile is costly due to similar reason except excavation is not as deep.
The soil that is suitable for this pile is not a characteristic of soil mentioned in Part II of
Foundation. These two alone proves that this foundation is not suitable for the mall.
Overall, there are more disadvantage to use Pile Foundation that using a Raft Foundation
despite its greater stability and capability in transferring greater loads to the soil.
Slab
1. Flat Slab
Flat slab is a reinforced concrete flat slab also known as beamless slab. It is basically a
structure that are supported directly by columns without beams. A part of the slab bounded
on each of the four sides by centre line of column named panel. Usually it is thickened close
to supporting column to provide enough strength in shear and to reduce negative
reinforcement in support regions.
Figure 3.3 Two way flat
plate and two way flat
slab.
Unfortunately, it have only medium spans and is not suitable for Malls such as The Gardens
Mall. It is necessary to know that The Gardens Mall holds a lot of mechanical conducting for
services such as air conditioning, water piping system and so on. Flat Slab have panels that
will interfere with these mechanical ducting. Should flat slab be reinforced, deflection at the
middle strip would be perilous.
2. Grid Slab
Grid Slab system involves beams spaced at regular intervals in perpendicular direction and
monolithic with slabs. They are usually employed for architectural use such as auditorium or
theatre halls. Voids in the ceiling in the form of rectangles or squares are advantageously
utilized for architectural lighting. Sizes of beam running in perpendicular directions are
generally kept the same. Sometimes, a diagonal grid is used instead of a rectangular beam.
Compared to Two-way slabs. Grid slab are found to be more efficient in load transferring. It
is distributed more evenly to the support due to the high surface area of the structure. This
reduce the cost of supporting structure such as heavy moving loads. Grid slabs could be
used anywhere in the plan giving architects more freedom in space planning.
Grid slab cost greatly due to complexity of its form which takes more labour work and more
surface area for formwork. When grid slab are used to support floors, fire protection is
required which is hard to achieve parsimoniously due to the high amount of surface area
needed to be covered.
Roof
1. Flat Roof
A flat roof is a low pitched roof and is defined in BS3589 as a pitch of 10o or less to the
horizontal. It is suitable for spans up to 4000mm, usually covered with a reinforced
concrete slab or patent form of decking.
It is agreeable among us that all malls should have a flat roof system because the
roof top can be used for many occasions. For example, the roof top can be used to
build a garden so that customer can enjoy the scenery. Opened air on the roof top
also enable customers to have a wonderful view over the city. Similar to One City
Mall, fine dining restaurants make use of the scenery for greater attraction. Roof top
dining is deemed romantic and considered popular.
The finishes used for flat roof are ceramic tiles and glass in the center. The ceramic
tiles provide good aesthetic qualities while glass can allow customers to have an
overhead view of the mall. That way, the mall won’t just have extra living space on
the roof top but also attract customers. For the roof top to hold restaurants, the
garden and the people on the roof, the roof is required to be strong in order to be
able to withstand such a load. Henceforth it is suggested that steel bar reinforced
concrete slab would be perfect for the job.
Unfortunately, there are several drawbacks in using flat roof system. Flat roof system
have poor insulators against the transfer of heat. In addition, should the roof is not
properly constructed, pools of water will collect on the surface after the rain. This
means that maintenance cost is needed. Another choice would be the roof to be
constructed with a slight pitch or a good drainage system. The roof must also have
waterproof membrane such as PVC to prevent leakage to the floors below.
2. Butterfly Roof
A butterfly roof is a V-shaped roof constructed of two tandem pieces which are
angled up on the outside. The midsection is angled downward where two pieces
meets the valley. This roof system is best used in bungalows in the west. Popular for
modern, eco-friendly and tropical home design.
The advantages of the roof is that the upper angle of the outer edges allows window
to be used, allowing natural light to enter. It is also pleasant and beautiful to view at.
This extraordinary type of roof design would, we all believe, attract more
shopaholic’s and noble’s attention.
The valley in the midsection of the butterfly roof allows rainwater to be collected,
making it beneficial for high drought areas. The water collected can also be used for
flushing toilets. A downspout is normally attached to a rain barrel is installed for this
reason.
The cons of the butterfly roof would be the complexity of the design that makes the
butterfly roof more expensive to build as well as maintaining it. Waterproofing in
butterfly roof must be ensured. Risk of a clogged drainage system will cause water to
pool or leak and will result in weakened columns weaken over time which could
cause immense casualty.
Conclusion
In brief, the importance of studying these horizontal elements in a building’s structure
begins with the analysis of structures that exists around us. What binds us to the bright
future of a greater civilization begins with research of those that can be analysed through, in
this case, observation alone.
There was a saying, “Life could only be understood backwards.” While similarly, the
structural elements of the existing building could be understood by studying the research
done by men who dedicated their time and blood to write down what they have learnt
through mistakes and experiment, both of which costs the lives of thousands of men, for the
sake of a greater civilization. Their hopes and effort will come to play, for what they have
recorded have benefited us not only the analysis and the understanding of the physics
applied within these structural elements but also the thousands of possibility of application.
From material to structural system, we now have the knowledge of how these structural
elements work in a building. What’s left to be explored is the creativity in using these
material and system to combine a new possible system, one that would bring us a step
further to the future. A step further to a greater civilization. A step forward to create a
better world for both nature and human.
For this, we say, appreciate all of the source provided by men who dedicated their lives for
us. Appreciate what men have built for us. Appreciate the knowledge we have explored and
shared in this report. Finally, appreciate the existence of all that is below and above the
clouds that watches over us.
Appendix
References
1. (n.d.). Retrieved November 16, 2014, from http://www.jwlowry.co.uk/wp-
content/uploads/Brown-Field-Site-and-Suitable-Foundation-Types.pdf
2. (n.d.). Retrieved November 16, 2014, from
http://www.concrete.org.uk/fingertips_nuggets.asp?cmd=display&id=347
3. (n.d.). Retrieved November 16, 2014, from http://www.ajer.org/papers/rase-2-
2013/Volume-3/DV120132027.pdf
4. (n.d.). Retrieved November 16, 2014, from
http://www.interscience.in/IJATCE_Vol1Iss2/paper20.pdf
5. (n.d.). Retrieved November 16, 2014, from
http://www.academia.edu/6389751/Analysis_And_Design_of_Flat_Slab_And_Grid_
Slab_And_Their_Cost_Comparison
6. (n.d.). Retrieved November 16, 2014, from
http://faculty.ksu.edu.sa/charif/Documents/Two way slabs.pdf
7. (n.d.). Retrieved November 16, 2014, from
http://www.engr.psu.edu/ae/thesis/portfolios/2012/RSD5028/Tech Reports/Tech
Report 2.pdf
8. (n.d.). Retrieved November 16, 2014, from
http://ebooks.narotama.ac.id/files/Reinforced Concrete Mechanics and Design (Sixth
Edition)/Chapter 13 Two-
9. All About Slabs. (n.d.). Retrieved November 16, 2014, from
http://theconstructor.org/structural-engg/all-about-slabs/471/
10. Analysis And Design of Flat Slab And Grid Slab And Their Cost Comparison. (n.d.).
Retrieved November 16, 2014, from
http://www.academia.edu/6389751/Analysis_And_Design_of_Flat_Slab_And_Grid_
Slab_And_Their_Cost_Comparison
11. Builder's Engineer. (n.d.). Retrieved November 16, 2014, from
http://www.abuildersengineer.com/2012/11/driven-piles-advantages-and.html
12. Civil Construction Tips. (n.d.). Retrieved November 16, 2014, from
http://civilconstructiontips.blogspot.com/2011/06/raft-foundation.html
13. Construction foundation question please help? (n.d.). Retrieved November 16, 2014,
from https://answers.yahoo.com/question/index?qid=20100509021956AAQYzZ7
14. Experts you should follow. (n.d.). Retrieved November 16, 2014, from
http://www.answers.com/Q/What_disadvantages_and_advantages_of_pad_founda
tions
15. Flat Slab Floor System. Advantages and Disadvantages of Flat Slabs - CivilDigital -
Anand Paul. (n.d.). Retrieved November 16, 2014, from http://civildigital.com/flat-
slab-floor-system-advantages-disadvantages-flat-slabs/
16. Flat slabs. (n.d.). Retrieved November 16, 2014, from
http://www.concretecentre.com/technical_information/building_solutions/frame_el
ements/slabs/flat_slab.aspx
17. Foundation, Concrete and Earthquake Engineering. (n.d.). Retrieved November 16,
2014, from http://civil-engg-world.blogspot.com/2012/06/what-is-raft-foundation-
difference.html
18. Mat or Raft Foundation | Advantages and Disadvantages of Raft Foundation. (n.d.).
Retrieved November 16, 2014, from http://civilengineersforum.com/raft-
foundation-advantages-disadvantages/
19. Midvalley City. (n.d.). Retrieved November 16, 2014, from
http://www.midvalleycity.com/main.html
20. New shopping malls in Klang Valley. (n.d.). Retrieved November 16, 2014, from
http://agentdiary.wordpress.com/2012/11/17/new-shopping-in-klang-valley/
21. One Way Slab Vs Two Way Slab | Difference Between One Way Slab and Two Way
Slab. (n.d.). Retrieved November 16, 2014, from
http://civilengineersforum.com/difference-between-one-way-slab-two-way-slab/
22. Pile foundations. (n.d.). Retrieved November 16, 2014, from
http://nuweb.northumbria.ac.uk/bedemo/Domestic_Foundation/page_13.htm
23. Raft Foundation. (n.d.). Retrieved November 16, 2014, from
http://constructionstudiesq1.weebly.com/raft-foundation.html
24. Various types of RCC Slabs | Design of RCC Structures | Civil Engineering Projects.
(n.d.). Retrieved November 16, 2014, from
http://www.civilprojectsonline.com/building-construction/various-types-of-rcc-
slabs-design-of-rcc-structures/
25. Domed roof. (n.d.). Retrieved November 16, 2014, from
http://www.build.com.au/domed-roof
26. Advantages of Domes - Dome of a Home. (n.d.). Retrieved November 16, 2014, from
http://domeofahome.com/dome-information/advantages-of-domes/
27. Mellon Arena. (n.d.). Retrieved November 16, 2014, from
http://openbuildings.com/buildings/mellon-arena-profile-
8921?_show_description=1
28. (n.d.). Retrieved November 16, 2014, from http://www.roofercalculator.com/top-15-
roof-types-and-their-pros-cons/#butterfly roof
29. What Is A Gambrel Roof (The Classic Dutch Colonial Design)? (n.d.). Retrieved
November 16, 2014, from http://www.energyauditingblog.com/what-is-a-gambrel-
roof/
30. Gambrel Roof Advantages. (2010, March 8). Retrieved November 16, 2014, from
http://www.ehow.com/list_6048978_gambrel-roof-advantages.html
31. Foster, J., & Harington, R. (1979). Nature of Building. InStructure and fabric, Part
1 (Revised ed., pp. 1-3). London: Batsford [etc.].
32. Foster, J., & Harington, R. (1979). Foundation. InStructure and fabric, Part 1 (Revised
ed., pp. 50-64). London: Batsford [etc.].
33. Foster, J., & Harington, R. (1979). Roof. InStructure and fabric, Part 1 (Revised ed.,
pp. 139-141). London: Batsford [etc.].
34. Francis DK Ching,Chapter 4. Building Construction Illustrated pg8-11 2008 publisher
is John Wiley & Sons., Inc
35. Francis DK Ching,Chapter 6. Building Construction Illustrated pg1-8 2008 publisher is
John Wiley & Sons., Inc
36. CHUDLEY, R. (1987). Construction technology 2 (2nd ed., pp. 130-131). Harlow:
Longman.
37. Chudley, R. (1987). Construction technology 1 (2nd ed., pp. 98-101). Harlow:
Longman
38. Peterson, Andrew (1996). The Dictionary of Islamic Architecture
39. Kuban, Doğan (1987). "The Style of Sinan's Domed Structures". Muqarnas 4: 72–97
-End-