Building structure project 1

Structural Design and Analysis Proposal for

VISITOR INTERPRETIVE CENTRE Valley of Hope, Sungai Buloh.

Project 1: Structural Design Post Mortem Building Structures (BLD61003) School of Architecture, Building and Design

Group Members: Ariventhar Ayahvoo || 0326428 Ng Jia Ying Angeline || 0326469 Leong Ching Wei || 0326495 Kok Sze Kuan || 0327896 Tan Zi Wen || 0327759 Yong Zhi Kang || 0327791 Tutor: Mr. Mohd. Adib Ramli

Table of Content 1.0 Introduction

02

2.0 Existing Design Review

04

2.1 Existing Design Orthographic Drawings 3.0 Design Appraisal and Proposed Solution

14

3.1 Column & Beam 3.1.1 Feasibility 3.1.2 Stability

15

3.2 Foundation 3.2.1 Feasibility 3.2.2 Stability

26

3.3 Floor Slab 3.3.1 Feasibility 3.3.2 Stability 3.3.3 Safety 3.3.4 Economy 3.3.5 Integration

29

3.4 Walls 3.4.1 Feasibility 3.4.2 Economy 3.4.3 Integration

39

3.5 Roof 3.5.1 Feasibility 3.5.2 Stability 3.5.3 Safety 3.5.4 Economy

45

4.0 Conclusion

51

4.1 Modified Orthographic Drawings 4.2 Conclusion 5.0 References

61

01

1.0 Introduction

02

1.0 Introduction Structure design is part of the general design problem and it is regarded as one of the most important design problems as it deals with life safety of the building occupants. For instance, no matter how architecturally beautiful a building is, if the structural design fails then the building would totally fail to the extend it will cause fatality. The aim of this project is to help students to better understand and appreciate structural design as students often left structural design as an afterthought rather than incorporated into the design process. Hence, they design irrational and uneconomical buildings that are lacking of basic structural understanding and structural behavior.

In this report, we are to reconsider the existing structural design applied in the previous Architectural Design Studio III Final Project - Visitor Interpretive Center (VIC). In a group of 6, we will discuss on solutions to improve the existing structural design and modification made to propose a new scheme with appropriate structural system.

Through the completion of this report, we will identify all the structural members, the material and describe the construction system used in the proposed design and reconsider the existing structural system in terms of Safety, Feasibility, Economy, Integration and Stability.

03

2.0 Existing Design Review

04

2.0 Existing Design Review The Visitor Interpretive Center (VIC) proposed is a 3 storey building which is built in local context with a hot and humid climate throughout the year. The average rainfall is 250 centimetres a year and the average temperature is 27 °C. Thus, the materials propose should also be able to keep the interior spaces cool and ventilated, at the same time rust-resistant. Building services like gutter system should also be integrated to prevent water stagnation.

The material of the existing building consist of steel column, timber flooring, load bearing wall and precast reinforced concrete slab roof. All in all, the whole existing building is covered by one single roof which is mainly supported by steel columns. The building is design in a way that wall is minimal, therefore creating an open concept. The whole structure is mainly supported by columns whereby load is distributed to the columns and to the ground.

PRECAST REINFORCED CONCRETE SLAB ROOFING LOAD BEARING GLASS STEEL BAR COLUMN

ROUGH CONCRETE PINEWOOD FLOORING

Figure 2.0.1 Axonometric of existing building

05

2.1 Existing Design Orthographic Drawings A

B

B’

Legend:

A’

Ground Floor Plan

Scale 1:150

06

2.1 Existing Design Orthographic Drawings A

B

VOID

9

B’

Legend:

A’ First Floor Plan

Scale 1: 150

07

2.1 Existing Design Orthographic Drawings A

10

B

VOID

B’

Legend: 10. Cafeteria

A’

Second Floor Plan

Scale 1:150

08

2.1 Existing Design Orthographic Drawings A

B

B’

A’

Roof Plan

Scale 1:150

09

2.1 Existing Design Orthographic Drawings

South Elevation Scale 1:150

11

2.1 Existing Design Orthographic Drawings

Section B-B’ Scale 1:150

13

3.0 Design Appraisal and Proposed Solution

14

3.1 Columns & Beams 3.1.1 Feasibility Problem Statement The existing columns and beams highlighted in figure 3.1.1.1. are made up of steel and they are directly exposed to outdoor atmosphere because the design is an open-plan building. This is not sustainable as steel is susceptible to corrosion in outdoor atmospheres and it requires a high maintenance fee to prevent rusting and prolong its serviceable life. Surface preparations such as paint, dry abrasive blasting, water blasting and substituting steel with corrosion-resistant alloys, can be applied but these corrosion-protecting methods are typically expensive and are restricted by practical limitations such as accessibility, location and time.

Furthermore, steel has very small resistance against fire as compared to concrete. Hot finished carbon steel begins to lose strength at temperatures above 300°C and reduces in strength at steady rate up to 800°C. Also, being an excellent conductor of heat, steel ignites materials in contact and causes fires to spread rapidly to other sections of a building. In this design, the fire would swiftly spread to the first floor and the roof through the steel columns and beams.

Fireproof treatment can be applied to steel structural elements but it is relatively expensive.

Figure 3.1.1.1 Steel column indicating in red in existing building section

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3.1 Columns & Beams 3.1.1 Feasibility Proposed solution Reinforced cement concrete would be the proposed material for the columns and beams because it have a relatively high strength in tension and compression, also cheaper as compared to steel. With proper construction and care, reinforced concrete is water resistant and will not corrode. However, it is important to note that the steel reinforcement inside should never be exposed. If it is exposed, the steel becomes compromised and can easily corrode, compromising the strength of the structure.

Concrete is a non-combustible material, and has a slow rate of heat transfer that makes the interior remains cooler than the surface. It is also chemically inert, making it impossible to catch alight. Concrete does not require any additional fire-protection because of its built-in resistance to fire. Therefore it can be used to minimise fire risk for the lowest initial cost while requiring the least in terms of ongoing maintenance.

There is an overall economy by using reinforced cement concrete because its maintenance cost is low. The raw materials which are required for reinforced cement concrete, cement, sand aggregate, water and steel, are easily available and can be transported easily.

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3.1 Columns & Beams 3.1.2 Stability Problem Statement i) The major issue identified from the columns used in the initial design are all of the same sizes ( 305 mm x 235 mm ) and it is not sufficient enough to withstand the load of the building. The existing columns are likely to fail by buckling according to the ratio of effective length to its minimum radius of gyration. ii) The random arrangement of columns are not in a grid pattern and some are placed either too closely or too far apart from each other with no beam to support the component above as seen in figure 3.1.2.1

figure 3.1.2.1 Existing ground floor column placement

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3.1 Columns & Beams 3.1.2 Stability Problem Statement iii) The parts which are highlighted in red as seen in figure 3.1.2.2 suggest the parts of the roof which lacks of support system.

The cantilevered upper floor (in dotted lines) in figure 3.1.2.3 which are only supported at one end does not meet the minimum requirement of the back span being double of the cantilevered distance, thus support structure has to be implemented.

figure 3.1.2.2 Existing roof plan

figure 3.1.2.3 Existing ground floor plan

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3.1 Columns & Beams 3.1.2 Stability Problem Statement Due to the columns placement which is not properly planned, the load is not well distributed to the ground and certain columns bear more loads compare to the other. The load path is as seen in figure 3.1.2.4

Figure 3.1.2.4 load path diagram

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3.1 Columns & Beams 3.1.2 Stability Proposed Solution i) To ensure the dead load and live load of the building are distributed evenly to the columns, the columns are spreaded out and rearranged according to a grid pattern as seen in figure 3.1.2.4 Columns are first placed at each corner of the floor slabs and roof to secure the component.

Then a complete row of columns are added based on the grid lines with the minimum distance between each column of 4m and maximum of 10m.

figure 3.1.2.4 Improved column placement according to grid

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3.1 Columns & Beams 3.1.2 Stability Proposed Solution ii) To determine the suitable sizes of each column throughout the design, the slenderness rule is applied. The slenderness rule is a measure of the propensity of a column to buckle. It is applied to determine the size of the columns based on its height from ground level considering the rotational and relative translational boundary conditions at the ends. The slenderness ratio must be smaller than 15, the slenderness ratio is defined as:

As for transfer beam, the beams are layed on top of each column transferring the load horizontally to columns at both ends after the column layout work is complete. The governing criteria of the rigidity of beams are usually the shear strength. It is suggested that a well-proportioned beam has a width as half its depth and that the span to depth ratio should be limited to 15.

The proposed arrangement of columns and beams of different sizes are shown in figure 3.1.2.5 to figure 3.1.2.7 in the following pages.

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3.1 Columns & Beams 3.1.2 Stability Proposed Solution Figure 3.1.2.5 shows the proposed arrangement of columns and beams of ground floor plan.

200 x 300 rcc column 225 x 225 rcc column Figure 3.1.2.5 improved structural ground floor plan

400 x 400 rcc column 500 x 500 rcc column 600 x 600 rcc column 800 x 800 rcc column

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3.1 Columns & Beams 3.1.2 Stability Proposed Solution Figure 3.1.2.6 shows the proposed arrangement of columns and beams of 1st floor plan.

200 x 300 rcc column 225 x 225 rcc column Figure 3.1.2.6 improved structural first floor plan

400 x 400 rcc column 500 x 500 rcc column 600 x 600 rcc column 800 x 800 rcc column

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3.1 Columns & Beams 3.1.2 Stability Proposed Solution Figure 3.1.2.7 shows the proposed arrangement of columns and beams of 2nd floor plan.

200 x 300 rcc column 225 x 225 rcc column Figure 3.1.2.7 improved structural second floor plan

400 x 400 rcc column 500 x 500 rcc column 600 x 600 rcc column 800 x 800 rcc column

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3.1 Columns & Beams 3.1.2 Stability Using grid lines to determine the arrangement of columns and the slenderness ratio to determine the dimension of columns, the stability of the building is hugely improved. Based on the proposed structural design, the load is now evenly distributed to all columns and to the ground as seen in figure 3.1.2.8

Figure 3.1.2.8 Improved load path diagram

Conclusion - Columns & Beams From the initial design, the main changes made to the columns are the materiality and the arrangement. The columns was changed from steel to reinforced concrete due to its strength and poor fitting to the local climate. Additional columns and beams was also added and rearranged for the load to be distributed evenly to the ground.

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3.2 Foundation 3.2.1 Stability & Feasibility Problem Statement i) In the initial design, the construction of foundation was not contemplated as seen in figure 3.2.1.1. Without foundation, the different structure of the building are not tied together and is most likely to collapse from sinking unevenly and crack. Foundation also provide support for structures, transferring their load to the ground that have sufficient bearing capacity and suitable settlement characteristics to support them. Due to the height of the building and the topography of the site, foundation is needed to prevent the building from falling over.

Figure 3.2.1.1 Existing building sectional view

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3.2 Foundation 3.2.1 Stability & Feasibility Proposed Solution i) Although the building’s structural load is relatively low compared to the bearing capacity of the surface soil, the building sits on ‘shrinkable’ soil. Shallow foundation with the minimum depth of 1 metre could be proposed to construct. This is due to the moisture content found in soil can result in contraction and expansion, generally to a depth of around 0.75 metre. Foundation must be deeper to prevent it from shifting due to ground movement.

Four types of shallow foundations as tabulated below : Types of foundation

Pad footing

Strip footing

Combined footing

Raft foundation

Location

isolated footing for individual point load

for load-bearing wall or row of columns that are closely spaced

connecting two isolated footings to supports two columns

spread load from columns and walls over large area

Advantage(s)

requires less excavation, size and shape can be varied depending on site condition, economic

more economical than providing a number of pad footings in one line when row of columns are closely spaced

load is evenly distributed

reduces differential settlements on non-homogeneous soils, differential movements between loading positions, requires less excavation

Disadvantage(s)

weak against uplift force and lateral forces

not ideal for framed construction

can prone to edge erosion if they are not treated properly

Section drawing

Table 3.2.1.1 Shallow foundation types & properties

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3.2 Foundation 3.2.1 Stability & Feasibility With reference to table 3.2.1.1, pad footing is the most suitable as the building columns are spread apart widely and it is able to isolate the individual point load. Strip footing and combined footing are not suitable to use for our design as they require the columns to be arranged closely together. Raft footings however are normally used in commercial building which is larger and heavier. Raft footings are also used when the footings would cover more than half of the construction area which is not in the case of our building. Pad footing is placed below each column to transfer the individual point load to the ground. The placement of pad footing can be referred to figure 3.2.1.2

Figure 3.2.1.2 pad footing placement

Conclusion - Foundation Building foundation was not considered in the initial design. Thus, pad footing was introduced to hold the structure above it and keep it upright. Pad footing was selected instead of strip or combined footing due to the arrangement of columns.

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3.3 Floor Slab 3.3.1 Stability Problem Statement i) In our initial design, the floor slab are fully made of timber Pinewood which is not rigid enough to support the dead and live load of the upper floors. When wood is loaded to a higher stress levels beyond the elastic range, bending force causes failures to occur. Besides, the long span between each beam may contribute to the bending of timber flooring as well.

Pinewood flooring

Large span Figure 3.3.1.1 bending force

Proposed Solution i) To solve the issue, reinforced concrete floor slab is proposed as concrete has a high compressive strength. The connection between reinforced concrete slab and reinforced concrete beams are more sturdy and rigid. Due to the reinforcement, reinforced concrete can also withstand a higher amount of tensile stress compared to timber floor slab.

With the consideration of maintaining the aesthetic value of timber, the floor slabs are covered with timber finishing. Thus, the aesthetic outlook of the interior spaces can be remained while achieving structural stability.

Floor joist

Timber wood finishing

Reinforced concrete floor slab Reinforcement bars Reinforced concrete beam

Figure 3.3.1.2 improved column to beam connections

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3.3 Floor Slab 3.3.1 Stability Problem Statement ii) The minimum requirement of concrete floor slab thickness is 100mm. For building which receive heavy loads such as motor homes or trucks are recommended to have thicker floor slabs. In our case, the reinforced concrete floor slab used in every floor are 300mm and far exceed the thickness required. Such heavy floor slabs also demand for thicker columns to support it and is not necessary as each floor does not require to carry any massive loads.

Proposed Solution ii) To determine the thickness of floor slab for each floor, the span to depth ratio is used. The span to depth ratio for simply supported floor slab could be derive from table 3.3.1.1. Using the span to depth ratio formula, the thickness of the floor slabs could be reduced for the same amount of load supported.

Table 3.3.1.1 Span to depth ratio for rectangular section and flanged beams

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3.3 Floor Slab 3.3.1 Stability The thickness of each floor slabs are derived from the calculation below using the span to depth ratio : 1.

Depth :

2.

Depth :

3.

Depth :

1 Span, L = 5000

2 Span, L = 4000

3 Span, L = 4800

Figure 3.3.1.3 1st Floor Plan

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3.3 Floor Slab 3.3.2 Feasibility Problem statement In the initial design, the floor is a pine wood floor. Timber is a natural product, and it needs to be treated accordingly. As a softwood, pine is more susceptible to dents and scratches, and fixing scratches may require refinishing the whole floor. Pine wood decking is high maintenance, it requires painting annually which can add to the cost of the decking. It will also need to be cleaned and resealed every year or so. Upkeep can be expensive and time consuming and boards may need to be replaced if weather damaged because moisture and humidity can cause warping. Treated pine has a lifespan of only 15 to 20 years.

Proposed solution Concrete floor is proposed to replace pine wood floor. This is because it is an economical choice with a relatively high strength in tension and compression. Concrete is extremely resilient and can withstand almost anything. Unlike wooden floors, using polished concrete floors in the building will last for years with very little maintenance because it is tough and resistant to damages and stains. Moreover, it would be easier to cast a concrete floor in terms of labour work.

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3.3 Floor Slab 3.3.3 Safety Problem Statement In the initial design, the flooring uses pinewood as the major material. Usage of softwood such as pinewood has a few disadvantages in its properties. Each three to four years, maintenance is crucial, whenever the structure is utilized all the time. Pinewood flooring has the tendency to be attacked by pests such as termites especially in tropical climates. Water leakage,spil or seep can easily damage the flooring as pinewood flooring is very sensitive to moisture.

Pinewood is also well known for being able to expand and contract when surrounding temperature and humidity fluctuate. Pinewood flooring surface tends to get easily damaged when there is high human traffic which makes it not advisable to be used as a flooring material at a large scale.

Figure 3.3.3.1 Prefinished Softwood Flooring

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3.3 Floor Slab 3.3.3 Safety Proposed Solution Porcelain Stoneware with Wood Texture Flooring : The proposed solution for the previous softwood flooring is the application of Concrete slab with Porcelain stoneware and wood texture flooring. The engineered tiles inspired from natural wooden boards is fire proof which helps prevent fire spread in the structure during fire incidents due to the high usage of this material as flooring around the structure. The stone material also prevents pests and termite attacks on the flooring throughout the structure.

Porcelain being the topmost surface is made of durable glaze which avoid liquids such as water from seeping into the flooring and acts as an ideal waterproofing material. Concrete slab as the base is highly recommended due to concrete being extremely tough and resilient.

Figure 3.3.3.2 Installation of Porcelain Floorware with Wood Texture on Site.

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3.3 Floor Slab 3.3.4 Economy Problem Statement & Proposed Solution

Types of material

Price

Life Span

Pinewood flooring

RM20/m2

> 100 years

Concrete flooring with timber finish

RM27/m2

> 100 years

Table 3.3.4.1 Comparison of price and life span for different materials

Concrete flooring is extremely tough and resilient, thus it requires a minimum amount of maintenance. Concrete have the choice of installing any floor surface covering over as it is smooth and free from holes, bumps, and defects. To maintain the aesthetic value of timber, we decided to cover the concrete flooring with timber finish as timber floor covering is long lasting, warm and rich aesthetically.

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3.3 Floor Slab 3.3.5 Integration Problem Statement (i) The spaces in the building do not have a proper lighting system. During night time or emergency use, it might face difficulties in viewing and walking around. Based on the UBBL : PART III- LIGHT AND VENTILATION supposed to be provided in buildings [By-Laws Sections 30 – 47]. To implement the lighting and ductwork into design, hiding these somewhere else without affecting the aesthetic value is part of the consideration we should take care of.

Figure 3.3.5.1 Existing ceiling floor with no integrated systems

Proposed Solution To integrate the service systems placement, we proposed to create interstitial or “sandwich” space above the floor ceilings and slabs which can help in hiding them without affecting the designated spaces for the users. At the same time, the volume of the intermediate spaces were saved by optimizing the undefined space.

Anyhow, with additional interstitial space above or beneath the ceiling floor, the height of each floor level needs to be increased by considering the human height. Thus, user still can feel the same spatial experience within the space.

Volume for Structure

Volume for Ducts

Volume for Lighting Figure 3.3.5.2 Incorporation of electrical system into a interstitial space within ceiling (Yong.Z.K, 2018)

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3.3 Floor Slab 3.3.5 Integration Problem Statement ii) The cylindrical opening, situated at the building centre might encountered flooding issues after heavy rain. To prevent flooding, certain spaces are recommended to have a proper water runaway system. In our case, the cylindrical glass wall used enclosed the spaces nicely, but the soil covered entirely the ground causing a weak flush when heavy rains hit onto the ground.

Figure 3.3.5.3 Existing cylindrical glass wall- fully enclosed

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3.3 Floor Slab 3.3.5 Integration Proposed Solution To solve the issue, we proposed to have a proper water drainage system with stone layered on top which can help in hiding them without affecting the aesthetic value. The drainage flow around the perimeter of the building to prevent rainwater accumulated the building ground.

Volume for Insulation and decking Volume for Structure Interstitial space

Volume for Ducts Volume for Lighting

Occupied Space

Floor to Ceiling height

Internal space

Cylindrical glass void

Internal space

Figure 3.3.5.4 Proposed glass wall drainage system (Yong.Z.K, 2018)

Conclusion - Floor Slab The main issue with the initial timber flooring was its stability and safety in terms of fire ratings.

Therefore, reinforced concrete floor slab with timber finishing was introduced to strengthen the overall structure. To ensure the safety in terms of fire rating, a layer of porcelain stoneware was added underneath the wood texture flooring. Besides, integration of water runaway system into the floor slab was also considered to prevent water stangnantation.

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3.4 Wall 3.4.1 Feasibility Problem statement The existing cylindrical glass wall highlighted in figure 3.4.1.1 is made up of load bearing glass as one of the structural materials in order to support the loads from the floor and roof slabs.

However in the improved design shown in figure 3.4.1.2, columns are added in grid manner to distribute the loads evenly. Thus, the cylindrical wall will not be the main structure that carry the loads. It is not economical to use load bearing glass in this case.

Figure 3.4.1.1

Figure 3.4.1.2

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3.4 Wall 3.4.1 Feasibility Proposed solution The proposed method is to change the load bearing glass to curtain wall as curtain wall is ideal outer wall that are non-structural, utilized to keep the weather out and the occupants in.

Being designed to resist air and water infiltration, absorb sway induced wind forces acting on the building and support its own dead load weight forces, the wind and gravity loads of the curtain wall are transferred to the floor line therefore the connections to anchor the curtain wall must be designed to allow differential movement while resisting the loads applied. The aluminium framing of the curtain wall is attached to the building structure and does not carry the floor or roof loads of the building.

Since the curtain wall is non-structural, and made of lightweight materials, thereby reducing the construction costs. .

Single Glazed Window

Aluminium framing

Figure 3.4.1.3 cylindrical curtain wall

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3.4 Wall 3.4.2 Economy Problem Statement & Proposed Solution The walls which are highlighted in red as seen in figure 3.4.2.1 are concrete load bearing walls supporting only its own load does not support any gravity loads from the building. The loads from the floors above are already supported by a set of columns and beams. These load bearing walls are unnecessary and could be change to non load bearing walls.

Figure 3.4.2.1 ground floor plan

Types of material

Price

Load bearing walls

RM110/m2

Non Load bearing walls

RM27/m2

Table 3.4.2.1 Comparison of price for different materials

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3.4 Wall 3.4.3 Integration Problem Statement (i) Urinal system is also part of the basic requirement for residential building. The building itself incorporated toilet space without a proper urinal equipments and design. The space within the toilet and the door swing is narrow which is not anthropometry wise for the users.

Figure 3.4.3.1 Existing toilet wall space

Proposed Solution To overcome this issue, we propose to enlarge the toilet unit space and reduce the quantity of the toilets in order to meet building purpose requirement and also the users needs. We also input the toilet bowl and a proper urinal system.

Figure 3.4.3.2 Proposed toilet cubicle wall space

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3.4 Wall 3.4.3 Integration Problem Statement (ii) The building glass wall exposed to strong and deep direct sunlight at east and west facade.

This will cause a lower thermal comfort level when users experience it.

Figure 3.4.3.3 Existing glass facade

Proposed Solution To prevent such direct solar radiation, we need to design some facade treatment to overcome the situation which help in reduce the indoor temperature. Hereby, we propose to design a light-shelf sun shading device onto the glass wall facing west. The sloped ceiling brings daylight deep into the room by translucent light-shelf which bounces light into classroom and provide diffuse light at window to prevent glare. The louvers block Malaysia’s sun which positioned high too.

Daylight Sloped roof Light Shelf with louvers Glass wall Direct sunlight

Figure 3.4.3.4 Incorporation of shading device into glass wall (Yong.Z.K, 2018)

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3.4 Wall Conclusion - Wall From the initial design, the main changes that was made to the wall was replacing the load bearing glass wall to single glazed glass with aluminium framing. Besides, the walls of the building are mostly load bearing walls which does not supports any structural load thus it was changed to non load bearing wall. Integration of urinal system and sun shading devices was also integrated within the walls.

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3.5 Roof 3.5.1 Feasibility Problem Statement (i) The existing roof structure which are highlighted in red as seen in figure 3.6.1.1 are made up of precast reinforced concrete slab. The precast reinforced concrete slab which span over 38 metre is eventually not conventional and susceptible to the whole roof. This is due to the fact that the transportation, handling difficulties and limitation in modification. The workers must be careful when handling precast concrete components to avoid damage. Precast reinforced concrete slab are manufacturers in plants, which are not always situated in the area of construction sites. Precast reinforced concrete slab must be carried from the plants to the sites using trailers. Usually, precast components are large and heavy, creating difficulties in transportation. Upon arrival at the sites, portable cranes or tower cranes will lift the precast components into place for erection. In the way to increase the speed of construction, several cranes are used requiring large space. Precast concrete system is not flexible when future modification is taken into account. (ii) The precast reinforced concrete slab required sophisticated connection work. The behaviour of connections determines the performance of precast concrete structures. When assembling of precast concrete structures, connections between precast components must be supervised and done properly to achieve the intended behaviour of a connection (simple, semi-rigid, or rigid). Apart from that, a good sound insulation can be provided and water leakage problem can be avoided. Skilled and well-trained labours are required to ensure proper connection is produced during erection stages, which lead to additional cost.

Figure 3.5.1.1 : Precast reinforced concrete slab indicating in red in the existing building section

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3.5 Roof 3.5.1 Feasibility Proposed Solution Types of roofing

Concrete

Wood Shingles

Metal

Clay

Advantage(s)

offer greater unobstructed span. having lesser beam and column, will provide larger open space. have high structural strength and rigidity.

wood materials helps to insulate the interior. has a relatively low weight..

made from recyclable materials. perfect as a sustainable building solution.

durable and long-lasting. has reflective properties which help to increase the efficiency of heating and cooling system.

Disadvantage(s)

the weight is high compared to its strength.

suffer degradation caused by moisture

may rust. metal is hard to seal completely from water penetration

heavy weight.

Table 3.5.1.2 : Properties of different types of roofing

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3.5 Roof 3.5.1 Feasibility Proposed Solution Constructing in an economical which lasts long and practical manner is an important criteria for producing a feasible roofing. Confirmed by Katharina Bause (2014) agreed that the feasibility study in economic sense are investigations that tend to determine whether a product development is a profitable and viable to proceed the proposed development.

The clay roof tiles highlighted in red as seen in figure 3.5.1.2 is proposed to be replaced the existing precast concrete slab roof . This is due to the fact that the thermal mass of clay roof tiles saves energy as the thermal mass of clay roof tiles is defined by a material’s specific heat, density and thermal conductivity. Materials with high values of these properties can passively store and release significant quantities of heat from the sun and actively or passively transfer the energy to interior spaces. Thus, it can be proved that clay roof tiles is energy efficiency.

Clay roof tile

Insulator Concrete slab

Figure 3.5.1.2 : Detail section of roofing

Clay roof tiles are solid and thus especially robust and dimensionally stable. They are insensitive to environmental influences such as heat and cold. As a result, roofs covered with clay roof tiles require very little maintenance and guarantee a constant quality and aesthetic.

Apart from that, clay tiles roof is characteristically flexible in term of annexes and refurbishments, it eventually can be quickly, easily installed or replaced. If a building has to be demolished, clay roof tiles can be sorted by type. This allows their quick recycling or reuses for new roofing and improvement of the water absorption capacity and soil subtraction.

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3.5 Roof 3.5.2 Stability Problem Statement In terms of stability, the original building’s roof is made of fully precast reinforced concrete slab with a thickness of 300mm and span over 38 metres long. The amount of load imposed on the structure is exceedingly high, the existing columns and beams are not sufficient enough to adequately support the entire load of the concrete roof.

Figure 3.5.2.1 Existing building section

Proposed Solution The proposed clay roof tile is more suitable as it weight 40% lesser than reinforced concrete roof. Concrete roof weights around 820 - 1100 pounds per square (100 sq. ft.), while majority of clay roofing tiles weigh only 600 - 650 pounds per square.

Besides, the thickness of roof can also be decrease from 300 mm to 250 mm to further reduce the load of the roof based on the span to depth ratio according to table 3.5.2.1

Table 3.5.2.1 Span to depth ratio for rectangular section and flanged beams

According to table 3.6.2.1, the span to depth ratio of simply supported slab should be 20.

The longest effective beam span of our building is 5000 mm, thus the suitable roof thickness is calculated as :

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3.5 Roof 3.5.3 Safety Clay Roof Tiles : In terms of safety, fire proofing is the major topic that will be analysed on. The most important factor in fireproofing buildings is understanding the combustibility rate of materials chosen. Clay roofing can withstand a melting point of at least 1,000°C temperature without splits, or break from fire. Clay roofing is also non combustible making it an idle solution to the roofing issue.The thermal improved thermal insulation increases the reduction of heat transfer and is 3°C cooler compared to concrete roofing. The light-hued coatings mirrors the sun's heat. Clay rooftops can last up to 50 years and even longer, contingent upon the seriousness of the climate. Clay rooftops are Class A roofing which are better than Class C materials like shingles as they spread the fire 2 feet lesser than Class C rooftops. This is because Class A materials are naturally non-combustible while Class C are flammable materials that are treated with synthetic substances to make them more fire retardant.

3.5.4 Economy Problem Statement & Proposed Solution

Types of material

Price

Life Span

Concrete Slab

RM20/m2

50 years

Wood Shingle

RM33/m2

25 years

Clay Tile

RM48/m2

150 years

Metal Sheet

RM40/m2

120 years

Table 3.5.4.1 Comparison of price and life span for different materials

Clay roof tile is chosen to replace concrete slab roof although it is more expensive because it’s more durable compared to concrete. Clay tiles are solid and thus especially robust and dimensionally stable, therefore, it can last up to 150 years while concrete can only last half that.

Clay tile can hold their color longer than concrete tiles as they will not easily fade due to exposure to sunlight. Tiled roofs are flexible as it can be quickly, easily and cost-efficiently installed or replaced in case of annexes and refurbishments. Clay roof tiles is sustainable, therefore they can be sorted by type which allows them to quickly and easily recycled or reused for new roofing, rooftop greening, road pavements and the improvement of the new water absorption capacity of soil substrata.

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3.5 Roof Conclusion - Roof From the initial design, precast reinforced concrete slab roof was replaced by clay roof tile due to its feasibility. Besides, the depth of the roof was also further reduce from the initial design to lessen the load imposed on the supporting structure and save cost.

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4.0 Conclusion

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4.1 Modified Orthographic Drawings A

B

B’

A’ Ground Floor Plan

Scale: 1:150

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4.1 Modified Orthographic Drawings A

B

VOID

B’

A’ First Floor Plan

Scale: 1:150

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4.1 Modified Orthographic Drawings A

B

B’

A’ Second Floor Plan

Scale: 1:150

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4.1 Modified Orthographic Drawings A

B

B’

A’

Roof Plan Scale: 1:150

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4.1 Modified Orthographic Drawings

South Elevation Scale 1: 150

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4.1 Modified Orthographic Drawings

Section B-B’ Scale 1: 150

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4.2 Conclusion The implementation of new structural design and materials used require several considerations.

These consideration includes examining its structural rigidity, feasibility, safety and economy.

The modification made to the existing design includes the super structure and sub structure such as roof, columns and beams, walls, slab and foundation. By implementing the new structural design and materials, the building is able to achieve structural stability and resistance to fire with a much lower cost.

Learning Outcome Throughout this project, we learnt to identify the structural load and forces faced in our design.

A design is not merely consist of concrete walls and columns. We have to consider the structural theory in designing structural elements in our design process. The technical standards, structural design codes and loading codes must also be applied to our building design.

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5.0 References

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5.0 References A clay tile roof is more than just a roof. (2018, September 26). Retrieved September 30, 2018, from https://clay-wienerberger.com/expertise/a-clay-tile-roof-is-more-than-just-a-roof An In-Depth Look at the Pros and Cons of Concrete Flooring. (n.d.). Retrieved October 1, 2018, from https://www.thespruce.com/in-depth-look-at-concrete-flooring-1314684 Concrete Network. (2018, July 27). Concrete Flooring Costs. Retrieved October 1, 2018, from https://www.concretenetwork.com/concrete/interiorfloors/cost.html Cost Versus Lifespan of Different Roofing Tiles. (n.d.). Retrieved September 29, 2018, from http://mtviewroofing.com/cost-versus-lifespan-of-different-roofing-tiles/ Designing Buildings Wiki Share your construction industry knowledge,ww.designingbuildings.co.uk. (n.d.). Retrieved from https://www.designingbuildings.co.uk/wiki/Glass_for_buildings EPDM Roofing – Advantages and Disadvantages. Retrieved from http://www.nvroofs.com/residential/roofing/roof-types/epdm-roofing-aka-epdm-rubber-roofin g -advantages-and-disadvantages/ For soil study type, effect and suggest onto structures choice(pg 26, pg 66, pg 153, pg 181, pg 281)not calculations. Retrieved September 10, 2018, from https://kwkhaing.files.wordpress.com/2014/12/budhu-soil-mechanics-foundations-3rd-txtbk. pdf Flat Roof Materials & Installation Costs 2018: PVC vs. TPO, EPDM Rubber. (2018, May 04).

Retrieved from https://www.roofingcalc.com/flat-roof-materials/indoor/outdoor wall/floor tiles with wood effect BENTON By PERONDA. (n.d.). Retrieved from https://www.archiproducts.com/en/products/peronda/indoor-outdoor-wall-floor-tiles-with-wo od-effect-benton_277025 Integrated building elements. Retrieved September 18, 2018, from https://design.ncsu.edu/building-systems-integration/building-systems-integration/ Learn how much it costs to Install a Wall. (n.d.). Retrieved October 1, 2018, from https://www.homeadvisor.com/cost/walls-and-ceilings/install-a-wall/ Says, E. T., Says, T., & Says, J. K. (2017, June 05). Advantages & Disadvantages of Glass as a Building Material. Retrieved September 22, 2018,from https://gharpedia.com/advantages-disadvantages-glass-building-material/ The lifespan of flooring: Is it measured in footsteps? (n.d.). Retrieved October 1, 2018, from http://www.improvementcenter.com/flooring/lifespan-of-flooring.html UBBL 1984 pdf. (2018). Retrieved from https://www.slideshare.net/JoshuaLee68/ubbl-1984-pdf W., S. (2014, September 19). What Are The Best Roofing Materials For Longevity? (n.d.).

Retrieved October 1, 2018, from https://www.thespruce.com/best-roofing-materials-for-longevity-1821951

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A building structure project done by the August 2017 architecture students of Taylor’s University