Saturday, September 19, 2020

Burj Khalifa

The Burj Khalifa, known as the Burj Dubai , is a skyscraper in Dubai, United Arab Emirates. With a total height of 829.8 m and a roof height of 828 m. The Burj Khalifa has been the tallest structure and building in the world since its topping out in 2009. 

Owner :  Emaar Properties

Architect : Adrian D. Smith 

Architectural style : Neo-futurism

Located at : Dubai

Construction started : 6th January,2004

Construction completed : 1st October,2009

Features:

1.The Dubai Fountain

 Outside, WET Enterprises designed a fountain system at a cost of 800 million. Illuminated by 6,600 lights and 50 coloured projectors, it is 270 m (900 ft) long and shoots water 150 m (500 ft) into the air, accompanied by a range of classical to contemporary Arabic and other music. It is the world's second largest choreographed fountain. On 26 October 2008, Emaar announced that based on results of a naming contest the fountain would be called the Dubai Fountain.

2.Observation deck

An outdoor observation deck, named At the Top, opened on 5 January 2010 on the 124th floor. At 452 m, it was the highest outdoor observation deck in the world when it opened. Although it was surpassed in December 2011 by Cloud Top 488 on the Canton Tower, Guangzhou at 488 m, Burj Khalifa opened the 148th floor SKY level at 555 m, once again giving it the highest observation deck in the world on 15 October 2014, until the Shanghai Tower opened in June 2016 with an observation deck at a height of 561 metres.

3.Burj Khalifa park

Burj Khalifa is surrounded by an 27-acre park designed by landscape architects SWA Group. Like the tower, the park's design was based on the flower of the Hymenocallis, a desert plant. At the centre of the park is the water room, which is a series of pools and water jet fountains. Benches and signs incorporate images of Burj Khalifa and the Hymenocallis flower. The plants are watered by water collected from the building's cooling system. The system provides 68,000,000 L annually. WET Enterprises, who also developed the Dubai Fountain, developed the park's six water features.

Construction Highlights :
Over 45,000 m3 of concrete, weighing more than 110,000 tonnes were used to construct the concrete and steel foundation, which features 192 piles buried more than 50 m (164 ft) deep. Burj Khalifa's construction will have used 330,000 m3 of concrete and 39,000 tonnes of steel rebar, and construction will have taken 22 million man-hours. 
The exterior cladding of Burj Khalifa began in May 2007 and was completed in September 2009. The vast project involved more than 380 skilled engineers and on-site technicians. At the initial stage of installation, the team progressed at the rate of about 20 to 30 panels per day and eventually achieved as many as 175 panels per day. The tower accomplished a world record for the highest installation of an aluminium and glass fa├žade with a height of 512 metres. 
The total weight of aluminium used on Burj Khalifa is equivalent to that of five A380 aircrafts and the total length of stainless steel bull nose fins is 293 times the height of Eiffel Tower Paris. In November 2007, the highest reinforced concrete core walls were pumped using 80 MPa concrete from ground level. A vertical height of 601 metres. 
This smashed the previous pumping record on a building of 470m on Taipei 101; the world’s second tallest tower and the previous world record for vertical pumping of 532 metres for an extension to the Riva del Garda Hydroelectric Power Plant in 1994. The concrete pressure during pumping to this level was nearly 200 bars. The amount of rebar used for the tower is 31,400 metric tons laid end to end this would extend over a quarter of the way around the world.

Burj Khalifa Construction Timeline:

  January 2004 : Excavation started
        February 2004 : Piling started
March 2005 : Superstructure started
June 2006 : Level 50 reached
  January 2007 : Level 100 reached
  March 2007 : Level 110 reached
  April 2007 : Level 120 reached
  May 2007 : Level 130 reached
  July 2007 : Level 141 reached (world's tallest building)
  September 2007 : Level 150 reached (world's tallest free-standing  structure)
  April 2008 : Level 160 reached ( world's tallest man-made  structure)
  January 2009 : Completion of spire (Burj Khalifa tops out)
  September 2009 : Exterior cladding completed
  January 2010 : Official launch ceremony




Friday, September 11, 2020

WOOD AND WOOD DERIVATIVES

 


Introduction :

Wood is a hard and fibrous substance which forms a major part of the trunk and branches of a tree. It can also be defined as a natural polymeric material which practically does not age. Wood as a building material falls in two major classes i,e, natural and man-made. With the advances in science and technology, wood in its natural form as timber, lumber, etc. is being rapidly replaced by composite wood materials in which natural wood is just a basic ingredient of a matrix or a laminate. The latter are found to be more useful and adaptable as they may be treated chemically, thermally or otherwise as per requirements. Some examples are plywood, fibreboards, chipboards, compressed wood, impregnated wood, etc.

Wood is a good absorber of shocks and so is suitable for construction work in hilly areas which are more prone to earthquakes. Finally, since wood can be easily worked, repairs and alterations to wood work can also be done easily. Owing to the above mentioned advantages, wood is very widely used in buildings as doors, windows, frames, temporary partition walls, etc. and in roof trusses and ceilings apart from formwork. 

Market Forms of Timber :

Battens: Timber pieces whose breadth and thickness do not exceed 50 mm. 

Baulk: Roughly squared timber piece, it is obtained by removing bark and Sapwood. One cross sectional dimension exceeds 50 mm, while the other exceeds 200mm. 

Board: A plank with parallel sides. Its thickness is less than 50mm and width exceeds 150mm. 

Deal: Piece of soft wood with parallel sides. Thickness varies from 50mm to 100mm and width does not exceed 230mm. 

Log: Trunk of tree obtained after removal of branches. 

Plank: Timber pieces with parallel sides. Thickness less than 50mm and width exceeds 50mm. 

Pole: Sound long log of wood, dia does not exceed 200mm, also known as spar.

Quartering: Square piece of timber, the length of side being 50mm to 150mm. 

Scantling: Timber piece whose breadth and thickness exceed 50mm,but are less than 200mm in length. These are the pieces of misc sizes of timber sawn out of a log. 

Types of engineered wood available in market:
a)Plywood
b)veneers
c)Fibre boards
d)Particle boards
e)Blockboard
f)Batten and Lamine boards

a)Plywood:
A wood panel glued under pressure from an odd number (usually 3 to 13) of layers/piles of veneers is known as plywood. The outer most veneer sheets in a plywood panel are called faces. The interior ply which have their grain directions parallel to that of the faces are termed as core or centre. Other piles which have grain directions perpendicular to that in the face are termed as cross bands.
Plywood may be classified upon direction of grains in the plies and on the type of adhesive used. Normally the alternate plies are oriented at 30° or 60° in star plywood. The faces are arranged with the grain at 45° to that of the centres in diagonal plywood. When the plies are bonded together with water-soluble glues such as casein glue, interior grade plywood is obtained and when bonded with phenol formaldehyde adhesive it is identified as exterior grade plywood which is completely water proof. 

Sizes available :
2400 x 1200 mm
2100 x 1200 mm
1800 x 1200 mm
2400 x 900 mm
2100 x 900 mm
1800 x 900 mm
Thickness vary from 3mm to 25mm.
Applications : Used for partitions, ceiling, door, concrete form work, etc.

b)Veneers :
The primary process in the manufacture of wood based products is veneering which produces thin sheets of wood known as veneers. The thickness of veneers varies from 0.4 to 0.6 mm. In no case it should exceed 1 mm. The most suitable wood for this purpose is walnut. However other species like teak, sissoo, rose wood, etc. are also used. The logs to be used for this purpose are kept in wet storage to avoid end splitting and are softened by heating with hot water or steam and the bark is removed. The log is then cut to veneers. Depending on the cutting process, the veneers are classified as rotary veneers and sliced veneers. These are used in the manufacture of plywood and other laminated boards.  

Sizes available:
i)Thickness vary from 0.4 to o.6 mm.
ii)In no case it should exceed 1 mm.
Applications : Used for doors, tops and side panels for cabinet, wooden flooring, etc.

c)Fibre boards:
These boards built up of felting from wood or vegetable (wood wastes, waste paper, agricultural wastes, etc.) are classified by the process of their moulding. If the boards are moulded by wet process, the main bond is by the felting of woody fibres and not by added glue. For the boards moulded by dry process, the bond between the predried fibres is improved by adding 4–8% of synthetic resin. For better performance wood preservatives and other admixtures are often added to the pulp. Insulating boards are not compressed during manufacture. Fibre boards are manufactured in various densities like soft, medium and hard. The soft boards are used for walls and ceilings. Medium boards find their application in panelling, partition walls, doors and windows. Hard boards have one surface smooth and the other one textured. These have higher densities, better mechanical properties, and improved moisture and termite resistances. The strength and weather properties of hard boards can be improved by oil tempertering and such boards are known as tempered hard boards. Some of the trade names of hard boards are Masonite, Celotex, Essex boards, etc.

Applications : Widely used for walls, ceiling, cladding, partitions, doors, perforated acoustic tiles, bus bodies, etc.

d)Particle boards :
They are manufactured from particles of wood or other ligno cellulose materials which are agglomerated, formed and pressed together by the use of an organic binder together in the presence of heat, pressure or moisture. They are manufactured from small timber pieces and wood wastes. The latter is first converted into small chips. The moisture content of chips is reduced to a certain percentage and then some gluing material, usually phenol formaldehyde, is sprayed. The chips are then spread to form a mat and then pressed in a hydraulic press in presence of heat and moisture. Particle boards avoid wastage of timber as in its making the entire volume of the fallen tree can be utilized. The trees used for making particle boards are eucalyptus, subabool, and rubber wood, and waste of saw mill. These boards provide dimensional stability, smooth uniform surface, and no difficulty in nailing.

Sizes available:
Sizes vary from 4ft to 8ft panels.
Applications : Widely used in buildings, ceilings, floor slabs, door, furniture, etc.

e)Block board :
The core of block boards is made up of strips of wood each not exceeding 25 mm in width, forming a slab, glued between at least two surface veneers. Veneers used for cross bands and faces are either rotary cut or sliced and should be reasonably smooth. Cross band thickness varies between 1–3 mm and face veneers between 0.5 to 1.5 mm in thicknesses. The directions of the grains of the core blocks run at right angles to that of the adjacent outer veneers. 

Sizes Available :
These are available in thicknesses of 12, 15, 19, 25, 30, 35, 40 and 50 mm. 
Block Boards are available in sizes - 
2400 × 1200 mm
2100 × 1200 mm
1200 × 900 mm
1800 × 1200 mm
1800 × 900 mm 
Applications : These are extensively used for construction of railways carriages, bodies of buses, marine and river crafts, partitions, furniture, etc. 

f)Batten and Lamine boards :
Batten boards have core made up of 80 mm wide wood pieces, forming a slab glued between at least two surface veneers. Whereas, Lamin boards have a core of strips, each not exceeding 7 mm in thickness, glued together to form a slab which in turn is glued between two or more outer veneers. The directions of the grains of the core block run at right angles to that of the adjacent outer veneers.


Wednesday, September 9, 2020

ANTHROPOMETRY

 

                                                                  VITRUVIAN MAN

       Anthropometry refers to the measurement of the size and proportions of the human body. While the architects of the Renaissance saw the proportions of the human figure as a reaffirmation that certain mathematical ratios reflected the harmony of their universe, anthropometric proportioning methods seek not abstract or symbolic ratios, but functional ones. They are predicated on the theory that forms and spaces in architecture are either containers or extensions of the human body and should therefore be determined by its dimensions. The difficulty with anthropometric proportioning is the nature of the data required for its use. For example, the dimensions given here in millimeters are average measurements and are merely guidelines that should be modified to satisfy specific user needs. Average dimensions must always be treated with caution since variations from the norm will always exist due to the difference between men and women, among various age and racial groups, even from one individual to the next.

      The dimensions and proportions of the human body affect the proportion of things we handle, the height and distance of things we try to reach, and the dimensions of the furnishings we use for sitting, working, eating, and sleeping. There is a difference between our structural dimensions and those dimensional requirements that result from how we reach for something on a shelf, sit down at a table, walk down a set of stairs, or interact with other people. These are functional dimensions and will vary according to the nature of the activity engaged in and the social situation. A special field that has developed from a concern with human factors is ergonomics the applied science that coordinates the design of devices, systems, and environments with our physiological and psychological capacities and requirements. In addition to the elements that we use in a building, the dimensions of the human body also affect the volume of space we require for movement, activity, and rest. The fit between the form and dimensions of a space and our own body dimensions can be a static one as when we sit in a chair, lean against a railing, or nestle within an alcove space. There can also be a dynamic fit as when we enter a building’s foyer, walk up a stairway, or move through the rooms and halls of a building. A third type of fit is how a space accommodates our need to maintain appropriate social distances and to have control over our personal space.

Scale :

     While proportion pertains to an ordered set of mathematical relationships among the dimensions of a form or space, scale refers to how we perceive or judge the size of something in relation to something else. In dealing with the issue of scale, therefore, we are always comparing one thing to another. The entity an object or space is being compared to may be an accepted unit or standard of measurement. For example, we can say that a table is, according to the U.S. Customary System, 3 feet wide, 6 feet long, and 29 inches high. Using the International Metric System, the same table would measure 914 mm wide, 1829 mm long, and 737 mm high. The physical dimensions of the table have not changed, just the system used to calculate its size. In drawing, we use a scale to specify the ratio that determines the relationship between an illustration to that which it represents. For example, the scale of an architectural drawing notes the size of a depicted building in comparison to the real thing.

Visual Scale :
       Of particular interest to designers is the notion of visual scale, which refers not to the actual dimensions of things, but rather to how small or large something appears to be in relation to its normal size or to the size of other things in its context. When we say something is small-scale or miniature, we usually mean that thing appears to be smaller than its usual size. Likewise, something that is large-scale is perceived as being larger than what is normal or expected. We speak of urban scale when we refer to the size of a project in the context of a city, or neighborhood scale when we judge a building appropriate to its locale within a city, or street scale when we note the relative sizes of elements fronting a roadway. At the scale of a building, all elements, no matter how plain or unimportant they may be, have a certain size. Its dimensions may be predetermined by the manufacturer, or they may be selected by the designer from a range of choices. Nevertheless, we perceive the size of each element in relation to other parts or to the whole of a composition. For example, the size and proportion of windows in a building facade are visually related to one another as well as to the spaces between them and the overall dimensions of the facade. If the windows are all of the same size and shape, they establish a scale relative to the size of the facade. If, however, one of the windows is larger than the others, it would create another scale within the composition of the facade. The jump in scale could indicate the size or significance of the space behind the window, or it could alter our perception of the size of the other windows or the overall dimensions of the facade.

Human Scale :
        Human scale in architecture is based on the dimensions and proportions of the human body. It has already been mentioned in the section on anthropometric proportioning that our dimensions vary from individual to individual and should not be used as an absolute measuring device. We can, however, gauge a space whose width is such that we can reach out and touch its walls. Similarly, we can judge its height if we can reach up and touch the ceiling plane overhead. Once we can no longer do these things, we must rely on visual rather than tactile clues to give us a sense of the scale of a space. For these clues, we can use elements that have human meaning and whose dimensions are related to the dimensions of our posture, pace, reach, or grasp. Such elements as a table or chair, the risers and treads of a stairway, the sill of a window, and the lintel over a doorway, not only help us judge the size of a space but also give it a human scale.

A Scaler Comparison :
      On these the architectural structures from various historic periods and places drawn to the same or similar scale. Our perception of how big something or someplace is always relative to its context and to the size of what we are familar with, such as the length of a Boeing 747 airliner.

REFERENCE :
FRANCIS D.K. CHING (Form Space Order)

Friday, September 4, 2020

CIRCULATION

 

What is circulation?????

The path of our movement can be conceived as the perceptual thread that links the spaces of a building, or any series of interior or exterior spaces, together. Since we move in Time through a Sequence of Spaces we experience a space in relation to where we’ve been and where we anticipate going. This artical presents building’s circulation system as positive elements that affect our perception of the forms and spaces of the building.

Main circulation elements :

1) Approach (The Distant View) :
Prior to actually passing into the interior of a building, we approach its entrance along a path. This is the first phase of the circulation system, during which we are prepared to see, experience, and use the spaces within a building.
The approach to a building and its entrance may vary in duration from a few paces through a compressed space to a lengthy and circuitous route. It may be perpendicular to the primary facade of a building or be oblique to it. The nature of the approach may contrast with what is confronted at its termination, or it may be continued on into the building’s interior sequence of spaces, obscuring the distinction between inside and outside.
a) Frontal:
A frontal approach leads directly to the entrance of a building along a straight, axial path. The visual goal that terminates the approach is clear; it may be the entire front facade of a building or an elaborated entrance within the plane.
b) Oblique:
An oblique approach enhances the effect of perspective on the front facade and form of a building. The path can be redirected one or more times to delay and prolong the sequence of the approach. If a building is approached at an extreme angle, its entrance can project beyond its facade to be more clearly visible.
c) Spiral:
A spiral path prolongs the sequence of the approach and emphasizes the three-dimensional form of a building as we move around its perimeter. 
The building entrance might be viewed intermittently during the approach to clarify its position or it may be hidden until the point of arrival.

2) Entrance (From Outside to Inside) :
   Entering a building, a room within a building, or a defined field of exterior space, involves the act of penetrating a vertical plane that distinguishes one space from another and,
separates ”here” from “there.” The act of entering can be signified in more subtle ways than punching a hole in a wall. It may be a passage through an implied plane established by two pillars or an overhead beam. In situations where greater visual and spatial continuity between two spaces is desired, even a change in level can establish a threshold and,
mark the passage from one place to another. In the normal situation where a wall is used to define and enclose a space or series of spaces, an entrance is accommodated by an opening in the plane of the wall. The form of the opening, however, can range from a simple hole in the wall to an elaborate, articulated gateway.
*The notion of an entrance can be visually reinforced by:
• making the opening lower, wider, or narrower than anticipated
• making the entrance deep or circuitous
• articulating the opening with ornamentation or decorative embellishment

3) Configuration of the Path (The Sequence of Spaces) :
All paths of movement, whether of people, cars, goods, or services, are linear in nature. And all paths have a starting point, from which we are taken through a sequence of spaces to our destination. The contour of a path depends on our mode of transportation. While we as pedestrians can turn, pause, stop, and rest at will, a bicycle has less freedom, and a car even less, in changing its pace and direction abruptly. Interestingly though, while a wheeled vehicle may require a path with smooth contours that reflect its turning radius, the width of the path can be tailored tightly to its dimensions. Pedestrians, on the other hand, although
able to tolerate abrupt changes in direction, require a greater volume of space than their bodily dimensions and greater freedom of choice along a path.
The nature of the configuration of a path both influences and is influenced by the organizational pattern of the spaces it links. The configuration of a path may reinforce a spatial organization by paralleling its pattern. Or the configuration may contrast with the form of the spatial organization and serve as a visual counterpoint to it. Once we are able to map out in our minds the overall configuration of the paths in a building, our orientation within the building and our understanding of its spatial layout will be made clear.
a) Linear
All paths are linear. A straight path, however, can be the primary organizing element for a series of spaces. In addition, it can be curvilinear or segmented, intersect other paths, have branches, or form a loop.
b) Radial
A radial configuration has linear paths extending from or terminating at a central, common point.
c) Spiral
A spiral configuration is a single, continuous path that originates from a central point, revolves around it, and becomes increasingly distant from it.
d) Grid
A grid configuration consists of two sets of parallel paths that intersect at regular intervals and create square or rectangular fields of space.
e) Network
A network configuration consists of paths that connect established points in space
f) Composite
In reality, a building normally employs a combination of the preceding patterns. Important points in any pattern are centers of activity, entrances to rooms and halls, and places for vertical circulation provided by stairways, ramps, and elevators.

4) Path-space Relationships (Edges, Nodes, and Terminations of the Path) :
Paths may be related to the spaces they link in the following ways. They may :
a) Pass by Spaces:
• The integrity of each space is maintained.
• The configuration of the path is flexible.
• Mediating spaces can be used to link the path with the spaces.
b) Pass through Spaces:
• The path may pass though a space axially, obliquely, or along its edge.
• In cutting through a space, the path creates patterns of rest and movement within it
c) Terminate in a Space:
• The location of the space establishes the path.
• This path-space relationship is used to approach and enter functionally or symbolically important spaces.

5) Form of the Circulation Space (Corridors, Halls, Galleries, Stairways and Rooms) :
Spaces for movement form an integral part of any building organization and occupy a significant amount of the volume of a building. If considered merely as functional linking devices, then circulation paths would be endless, corridor-like spaces. The form and scale of a circulation space, however, should accommodate the movement of people as they promenade, pause, rest, or take in a view along a path.
The form of a circulation space varies according to how :
• its boundaries are defined;
• its form relates to the form of the spaces it links;
• its qualities of scale, proportion, light, and view are articulated;
• entrances open onto it; and
• it handles changes in level with stairs and ramps.
A circulation space may be:
a) Enclosed
Forming a public galleria or private corridor that relates to the spaces it links though entrances in a wall plane;
b) Open on One Side
Forming a balcony or gallery that provides visual and spatial continuity with the spaces it links.
c) Open on Both Sides
Forming a colonnaded passageway that becomes a physical extension of the space it passes through. The width and height of a circulation space should be proportionate with the type and amount of movement it must handle. A distinction in scale should be established between a public promenade, a more private hall, and a service corridor.

REFERENCE : FRANCIS D.K. CHING (FORM, SPACE, & ORDER)

Tuesday, September 1, 2020

ROOF SYSTEMS

 

       The roof system functions as the primary sheltering element for the interior spaces of a building. The form and slope of a roof must be compatible with the type of roofing shingles, tiles, or a continuous membrane used to shed rainwater and melting snow to a system of drains, gutters, and downspouts. The construction of a roof should also control the passage of moisture vapor, the infiltration of air, and the flow of heat and solar radiation. And depending on the type of construction required by the building code, the roof structure and assembly may have to resist the spread of fire.

      Like floor systems, a roof must be structured to span across space and carry its own weight as well as the weight of any attached equipment and accumulated rain and snow. Flat roofs used as decks are also subject to live occupancy loads. In addition to these gravity loads, the planes of the roof may be required to resist lateral wind and seismic forces, as well as uplifting wind forces, and transfer these forces to the supporting structure.

      Because the gravity loads for a building originate with the roof system, its structural layout must correspond to that of the column and bearing wall systems through which its loads are transferred down to the foundation system. This pattern of roof supports and the extent of the roof spans, in turn, influences the layout of interior spaces and the type of ceiling that the roof structure may support. Long roof spans would open up a more flexible interior space while shorter roof spans might suggest more precisely defined spaces.

     The form of a roof structure whether flat or pitched, gabled or hipped, broad and sheltering, or rhythmically articulated has a major impact on the image of a building. The roof may be exposed with its edges flush with or overhanging the exterior walls, or it may be concealed from view, hidden behind a parapet. If its underside remains exposed, the roof also transmits its form to the upper boundaries of the interior spaces below.

TYPES OF ROOFS :-

1) Flat Roofs

•Minimum recommended slope:1/4" per foot

•Flat roofs require a continuous membrane roofing material.

•The roof slope may be achieved by inclining the structural members or roof deck, or by tapering the layer of thermal insulation.

•The slope usually leads to interior drains. Secondary,emergency overflow roof drains or scuppers are required in cases where water might be trapped if the primary roof drains are blocked. 

•Flat roofs can efficiently cover a building of any horizontal dimension, and may be structured and designed to serve as an outdoor space.

2) Sloping Roofs

•Sloping roofs may be categorized into

a)Low-slope roofs - upto 3:12

b)Medium-to high-slope roofs - 4:12 to 12:12

•The roof slope affects the choice of roofing material, the requirements for underlayment and eave flashing, and design wind loads.

•Low-slope roofs require roll or continuous membrane roofing; some shingles and sheet materials may be used on 3:12 pitches.

•Medium and high-slope roofs may be covered with shingles, tiles, or sheet materials.

•Sloping roofs shed rainwater easily to eave gutters.

•The height and area of a sloping roof increase with its horizontal dimensions.