Transcript Presentation -Col Murtaza

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Climate and Building Design
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Building Structural/Construction Systems
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The combinations of materials used to build the main
elements of our homes: roof, walls and floor are referred to as
construction systems. They are many and varied and each has
advantages and disadvantages depending on climate, distance
from source of supply, budget and desired style and
appearance. The different building systems are:
The traditional kacha houses with walls of sun dried mud
( adobe) and wooden roof. Wooden frames provided as bonds
at different levels along the length of walls.
Bhonga houses with conical roof of inner dia 3 to 6 m with
adobe walls and bamboo framed roof covered with thatch.
The walls also having wooden frames.
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Single story brick/ Block masonry houses with
reinforced concrete roofs. Ext. Wall: 13.5 in , Int.
Walls: 9 in Block masonry: 8 in – Wooden roof
truss with CGI sheets or RCC 4 in thick slab.
Stone masonry walls and Wooden and CGI sheets
roofs. Stone masonry walls and RCC roofs
Reinforced Concrete Structures.
Frame structures with columns, beams and slab
connections.
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Conditions in selection of structural systems
1. Soil conditions
2. The program and concept
3. Applicable codes
4. Potential code changes
5. Flexibility
6. Impact on finished-ceiling and building height
7. Material delivery and construction timing
8. Local construction capabilities and preferences
9. Ease of construction and schedule
10. Cost of the selected system
11. Cost impact on other systems
12. Appearance and aesthetic potential
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Environmental Considerations in Selecting the Building
Structure System
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Make more efficient use of existing materials.
Minimize the amount of waste.
Use materials with least environmental impact.
Consider both operational and whole lifecycle performance of
materials and designs.
Use fully recycled materials or materials with recycled content.
Re-use whole buildings or parts thereof to reduce consumption
of new materials.
Choose materials with a lifespan equivalent to the projected life
of the building.
Design to extend building lifespan (current average 50 years aim for 100+).
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Design and build for de-construction, re-use, adaptation,
modification and recycling.
Encourage development of new, efficient, low impact
materials and applications by creating demand.
Consider how and where the materials are sourced and the
impacts this causes.
Minimize the energy used to transport materials by using
locally produced material. Use of lightweight material where
appropriate also reduces transportation energy.
Minimize the energy used to heat and cool the building by
using materials that effectively modify climate extremes.
Understand how chemicals used in the manufacture of some
materials might affect your health.
Minimize or eliminate emissions during use and manufacture. 7
1. Mud brick (Adobe)
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The ideal building material would be
'borrowed' from the environment and replaced
after use. There would be little or no processing
of the raw material and all the energy inputs
would be directly, or indirectly, from the sun.
This ideal material would also be cheap. Mud
bricks come close to this ideal, or they can do.
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The appearance of mud bricks reflects the
material they are made from. They are thus
earthy, with color determined by color of clays
and sands in the mix. Finished walls can express
the brick patterns very strongly at one extreme
or be made into a smoothly continuous surface.
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Performance parameters of Mud
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Structural capability
With thick enough walls, mud brick can create load bearing structures up to
several stories high.
Thermal mass
Adobe walls can provide moderate to high thermal mass, but for most
climatic conditions, as a rule of thumb, walls should be a minimum of 300
mm ( 12in) thick to provide effective thermal mass.
Insulation
Contrary to popular belief mud bricks are not good insulators. Since they
are extremely dense they lack the ability to trap air within their structure.
Insulation can be added to adobe walls with linings.
Fire and vermin resistance
Since earth does not burn, and earth walls do not readily provide habitat
for vermin, mud brick walls generally have excellent fire and vermin 9
resistance.
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Durability and moisture resistance
Adobe walls are capable of providing structural support for
centuries but they need protection from extreme weather (eg. with
deep eaves) or continuous maintenance (the ancient structures of the
Yemen have been repaired continuously for the centuries they have
been standing). As a general rule, adobe needs protection from
driving rain (although some adobe soils are very resistant to
weathering) and should not be exposed to continuous high moisture.
Breath-ability and toxicity
Mud bricks make 'breathable' walls but some mud brick recipes
include bitumen, which potentially results in some out gassing of
hydrocarbons. Ideally earth should be used in its natural state or as
near it as can be achieved.
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Sustainability (Environmental impacts)
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Mud bricks have the potential to provide the lowest impact of
all construction materials. Adobe should not contain any
organic matter
Build-ability, availability and cost
Mud bricks provide a forgiving construction medium well
suited to owner-builder construction.
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2. Concrete slab floors
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Concrete slab floors come in many forms and can
be used to provide great thermal comfort and
lifestyle advantages.
Benefits:
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Thermal Mass describes the potential of a material to
store and re-release thermal energy. Highest here
Durability is one of the other main advantages of
concrete slabs.
Termite resistance is achieved with concrete slabs by
designing and constructing them in accordance with the
code.
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Design parameters of Concrete slabs
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Passive solar design principles and high mass construction work
well together, and concrete slabs are generally the easiest way to
add thermal mass to a house .
Natural ventilation must be provided for in the design
Insulation of the slab edge is important in cooler climates, to
prevent warmth escaping through the edges of the slab
Balconies extended from the main slab of a house may act as
cooling or heating fins, carrying precious warmth away to the cold
exterior during winter, or transferring heat from summer sun inside .
Acoustics need to be considered.
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3. Clay brick
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Clay brickwork is made from selected clays that are molded
or cut into shape and fired in ovens.
The firing process transforms the clay into a building
component with high compressive strength and excellent
weathering qualities, attributes that have been exploited for
millennia to build structures ranging from single-storey
huts to enormous viaducts.
Clay brickwork is most widely used in external cladding
and load bearing wall medium and continues to enjoy rapid
growth in its use.
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Performance Summary
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Appearance
Clay brickwork is available in a great variety of natural
colors and textures derived from fired clay used in
combination with cement mortar joints of various colors and
finishes.
Structural capability
The high compressive strength of fired clay bricks has been
exploited for millennia to build structures ranging from
single-storey huts to massive public buildings and enormous
bridges and viaducts.
Thermal mass
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Clay brickwork has high thermal mass.
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Insulation
Clay brickwork, combined with internal and external
air films and a cavity, has moderate thermal resistance.
Sound insulation
Due to their mass, clay bricks provide excellent sound
insulation, particularly for low frequency noise.
Vermin resistance
Clay brickwork consists of dense inorganic materials
that do not harbor vermin.
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Sustainability (environmental impacts)
Clay brick manufacture uses energy but the investment of embodied
energy is repaid by the longevity of the material.
Clay brick homes have a long life and low maintenance costs
making them a potentially sustainable form of construction.
Option 1
: Brick veneer/timber frame/concrete slab
Option 2
Brick veneer/steel frame/concrete slab
Option 3
Double brick/concrete slab
Option 4
Timber clad/steel frame/concrete slab
Option 5
Timber clad/timber frame/concrete slab
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4. Lightweight timber
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Wooden structures have been used in all kinds of
building types for many years.
In a world living with the effects of global warming,
timber provides a renewable building material that
stores carbon in its production.
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Performance Summary
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Appearance
Aesthetically, timber possesses a natural attractiveness that
people readily relate to.
Structural capability
Timber has good compressive strength but is strongest in
tension
Thermal mass
In general timber has low thermal mass
Insulation
Timber is a natural insulator due to air pockets within its19
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Sound insulation
The sound insulation of walls is usually obtained by
providing a barrier of sufficient mass to absorb the sound
energy.
Fire Resistance: very low
Durability and moisture resistance
Timber is an organic material and deteriorates due to
weathering.
Toxicity and breath ability: Timber is generally nontoxic.
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Sustainability (environmental impacts)
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Timber is a renewable building resource that absorbs
carbon it its production.
A lightweight timber construction can be built for
deconstruction, and timbers from the construction reused or
recycled at the end of its use in the building.
It has tremendous capacity to provide a sustainable
construction option.
Timber is completely biodegradable and can even be
composted if no reuse application can be found.
Build ability, availability and cost
Lightweight timber construction is relatively simple to
build.
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Choice of Appropriate Building Materials
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The "appropriateness" of a building material or
construction technology can never be generalized.
The following questions show some of the main factors,
which determine appropriateness:
 Is the material produced locally, or is it partially or
entirely imported?
 Is it cheap, abundantly available, and/or easily
renewable?
 Has it been produced in a factory far away
(transportation costs!);
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Does it require special machines and equipment,
or can it be produced at lower cost on the building
site? (Good quality and durability are often more
important than low procurement costs).
 Does its production and use require a high-energy
input, and cause wastage and pollution? Is there an
acceptable alternative material, which eliminates
these problems?
 Is the material and construction technique
climatically acceptable?
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Does the material and construction technique provide
sufficient safety against common natural hazards (e.g. fire.
biological agents, heavy rain, hurricanes, earthquakes)?
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Can the material and technology be used and understood
by the local workers, or are special skills and experience
required?
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Are repairs and replacements possible with local means?
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Is the material socially acceptable? Is it considered low
standard, or does it offend religious belief? Does it match
with the materials and constructions of nearby buildings?
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Recorded Historical
Perspective
BACK GROUND
John Ruskin (1819-1900)
The Arts And Crafts Movements
(William Morris – 1834-1896)
Art Nouveau: 1890-1905
Victor Horta (1861-1947)
Frank Lloyd Wright (1867-1959)
Design For The Machine Age
(1900-1930)
De Stijl (1917 – 1931)
The Bauhaus (1919 – 1933)
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Eco Materials
Definition :Materials those have, the lowest
possible negative impact to the natural
environment, minimal net negative impact
to the natural environment, and maintain
some reasonable level of human
satisfaction in their technological and
socioeconomic performance could be
defined as "eco-materials".
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Eco Materials
 Assessment System
 Japanese Study
 Study By Technical Research Center Of
Finland
 Study By National Institute Of Building
Sciences (USA)
 Study By American Institute Of
Architect’s Environmental Resource
Guides
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GUIDELINE PRINCIPAL FOR MATERIALS
Avoid Ozone-depleting Chemicals In Mechanical
Equipment And Insulation.
Use Durable Products And Materials
Choose Low-maintenance Building Materials
Choose Building Materials With Low Embodied Energy.
Buy Locally Produced Building Materials
Use Building Products Made From Recycled Materials
Use Salvaged Building Materials When Possible.
Seek Responsible Wood Supplies.
Avoid Materials That Will Off gas Pollutants.
Minimize Use Of Pressure-treated Lumber.
Minimize Packaging Waste.
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Construction Material Used In Outer Walls
(Percentage) By Rural/Urban 1998
Construction Material
All Areas
All Categories
Baked
Bricks/Blocks/Stones
Unbaked Bricks/Mud
Wood/Bamboo
Others
1998
Rural
Urban
100
58.46
100
45.96
100
85.76
34.48
44.69
12.16
5.42
1.64
7.20
2.14
1.50
0.54
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CONSTRUCTION MATERIAL USED IN ROOFS
(PERCENTAGE) BY RURAL/URBAN 1998
Construction Material
All Areas
1998
Rural
Urban
All Categories
RCC/RBC
Cement/ Iron Sheet
100
21.39
13.07
100
10.43
10.05
100
46.35
19.69
Wood/Bamboo
Others
57.35
8.18
69.76
9.76
30.23
4.74
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Construction
Material Used In
Housing Units By Tenure
Owned
Rented
Housing Units
Rent-free
Total
Recent
Outer Walls
Baked Bricks / Block /
Stones
8,986,336
1,457,13
1
787,454
11,230,291
58.46
Unbaked Bricks / Earth
Bound
5,523,351
176,179
924,765
6,624,295
38.48
Wood / Bamboo
842,464
17,531
181,828
1,041,823
5.42
Others
245,104
8,414
61,181
314,699
1.64
Roof
RCC / RBC
2,933,671
859,521
317,074
4,110,266
21.39
Cement / Iron Sheets
2,012,871
341,804
157,075
2,511,750
13.07
Wood / Bamboo
9,334,805
397,011
1,285,785
11,017,601
57.35
Others
1,315,908
60,919
195,294
1,572,121
8.18
Total
15,597,25
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1,659,25
5
1,955,228
19,211,738
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100.00
Pakistan – Rural
Outer Walls
Baked Bricks /
Block / Stones
5,470,9
56
205,316
381,85
1
6,058,12
3
45.96
Unbaked Bricks /
Earth Bound
4,967,6
80
74,485
848,50
8
5,890,67
3
44.96
Wood / Bamboo
777,800
8,701
162,92
8
949,429
7.20
Others
224,109
4,305
53,669
282,083
2.14
Roof
RCC / RBC
1,194,0
63
97,148
83,849
1,375,06
0
10.43
Cement / Iron
Sheets
1,210,9
88
38,844
74,363
1,324,19
5
10.05
Wood / Bamboo
7,933,3
80
139,263
1,121,
879
9,194,52
2
69.76
1,102,11
17,552
166,86
1,286,53
Others
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9.76
PAKISTAN – URBAN
OUTER WALLS
3,515,380
1,251,8
15
405,603
5,1
72,
798
85.76
555,671
101,694
76,257
733
,62
2
12.16
Wood / Bamboo
64,664
8,830
18,900
92,
394
1.53
Others
20,995
4,109
7,512
32,
616
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Baked Bricks / Block /
Stones
Unbaked Bricks / Earth
Bound
Roof
RCC / RBC
1,739,608
762,373
233,225
2,735,206
45.35
801,883
302,960
82,712
1,187,555
19.69
1,401,425
257,748
163,906
1,823,079
30.23
Others
213,794
43,367
28,429
285,590
Total
4,156,71
1,366,4
508,272
6,031,430
Cement / Iron Sheets
Wood / Bamboo
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4.47
100.0