Unit – 2
INTRODUCTION TO BUILDING AND TOWN PLANNING
In a residential building two factors are of great importance, the site and the planning of the building before it is constructed.
After selecting a suitable site ,the next step of building in the planning.
Plan : The arrangement of various rooms in the building is known as plan or design of building. Concept of plan: while attempting to plan of a building , the main criteria to be constantly kept in mind by the engineer is the general scope or purpose of the building .
Each type of building has its own requirements to suit its purpose in the best possible manner.
To develop the plan of the building sizes of rooms, their location, position of passages and other amenities, etc are considered.
A building used for dwelling purpose is known as residential building.
Management is a social and scientific process of defining the objectives, planning, organizing, coordinating, motivating, controlling and harnessing the resources of an organization at the optimum level to achieve predetermined goal.
Principal of Planning
- Aspect
- Prospect
- Privacy
- Circulation
- Roominess
- Grouping
- Elegance
- Sanitation
- Flexibility
- Economy
- Practical consideration
Aspect
Placement of different rooms of house in accordance with our activities at different hours of day. Rooms should get enough sunlight and air, which gives, Great environment, Comfort etc. A room which receives light & air from particular direction is said to have ‘aspect’ of that direction.
Prospect
Prospect is the view from outside of a house. The house should have a proper prospect so that it can give a feeling of cheerfulness to the people living in it. It should create a good impression on a person who views it from outside. It must also possess good qualities like comfort, cheerfulness, security, labour saving and modern outlook. For e.g. Small Projections or bay window can have a good out-look as well as helps in providing breeze, light and sunlight to the room.
Privacy
It is an important principle while planning a residential building. Privacy can be maintained in ways: 1. External 2. Internal
- External Privacy
The privacy from sides can be secured by providing planned entrance and pathways. This can achieved by screening the front and rear entrance.
2. Internal Privacy
Privacy in internal rooms can be easily obtain by proper planning of diff. Areas and location of doors and windows. The shutter when opened should give the minimum view of room for an entering persons.
Circulation
Circulation is movement within the premises and includes both horizontal and vertical circulation. Horizontal circulation ( room to room) ,Passage , Corridors , Lobbies etc. Vertical circulation (floor to floor) – Stairs
Roominess
Roominess means getting maximum advantage from the minimum dimension of the room. The effect of roominess depend on the relative dimension of length, width and height of room. The shape and size of the room are also very important for roominess. A rectangular room has more roominess then square room in same area.
Grouping
Grouping means the arrangement of various rooms in the building for the convenience of user. It minimizes the circulation and at the same time improves the comfort. A dining room should be close to kitchen ,while sanitary be away from kitchen, but convenient to bed rooms.
Elegance
Elegance is grand appearance of a building attained mainly owing to the elevation which in turn depends on the plan. It depends upon proper positioning/selection of doors, windows, balcony, roofs, staircase etc. For better elegance . Selecting superior building material for facing as polished stone- granite, marble or mosaic. Providing projection like sunshades, balconies, porch with or without pergola opening. Providing bay window, corner window, etc.
Sanitation
It includes providing light ,ventilation, cleanliness, water supply and sanitary amenities. For residential building window area should not less then 1/10th of floor area. In school not less than 1/5th of the floor area.
Flexibility
Flexibility means that a room which is planned for one function be used for other, if required. Like study room may be planned for using guest room. Etc.
Economy
The building should have minimum floor area with maximum utility. It will reduce cost of the building .hence, it will be economical. Economy can achieved by: Providing simple elevation. Reducing the storey height. Dispensing of porches, lobbies and balconies.
Practical Consideration
After the all fundamental some practical points should be additionally considered: Provision for future extensions without dismantling should be made while planning. Strength, stability, convenience and comfort of occupants, should be the first consideration while planning. As far as possible sizes of rooms should be kept large. Large room can be shortened by providing movable partition but smaller room cannot be enlarge easily. The number of door and window should be minimum provisions for built in furniture at proper places are useful from point of view of utility.
BUILDING DRAWING
The drawing is the language of the engineers. This language is expressed not in words but in the shape of lines and figures. The shape of lines and figures everywhere in the world have got the same meaning
The main aim of building drawing is to give sufficient information by the designer to the construction engineer.
Plan
The plan of the building gives the general alignment or location of different rooms of the building. Plan draw in building drawing is not simply the top seen from the top of the building. The building is imagined to be cut by a horizontal plane at the sill of the window. Upper portion is removed on a horizontal plane below the building will be known as plan.
Elevation
Elevations are orthographic projections of a building produced by its architect or designer.
Section
A cross-section showing a slice through the wall gives builders, joiners and roofers a great deal of information about how the house should be built.
Sections can be shown through any part of the building and normally a scale of 1:20 is used. The local building control department needs sectional views and floor plans to assess the quality of construction design.
Principles of Town Planning
Town planning cannot be studied in isolation. It involves the study of various subjects such as engineering, architecture, surveying, transportation planning etc. The intention of the town planning is to satisfy the needs of our future generations and prevent the haphazard growth of the town. Some of the guiding principles of town planning are as follows:
1. Zoning
The town should be divided into suitable zones such as commercial zone, industrial zone, residential zone, etc and suitable rules and regulations should be formed for the development of each zone.
2.Green belt
Green belt is non-development zone on the periphery of the town. It prevents the haphazard sprawl of the town restricting its size. In essence, a green belt is an invisible line designating a border around a certain area, preventing development of the area and allowing wildlife to return and be established. Greenways and green wedges have a linear character and may run across the town and not around the town.
3. Housing
Housing has to be carefully studied and designed to suit the local population. Care should be taken to see that there is no development of slums since it would be responsible for degrading the life of the citizens. There are various types of housing styles. When a land use plan is made, zones for independent housing, midrise buildings, high rise buildings are allocated. Land use maps are of two types. Type 1 helps us study the land use on a broad range. All we can see are the residential, commercial and recreational zones.
4. Public buildings
Public buildings should be well grouped and distributed throughout the town. Unnecessary concentration of public buildings should be avoided. Factors such as parking facilities, road widths have to be taken into consideration while allocating the space for public buildings.
5. Recreation centres
Recreation centres have to be given importance while designing a town. They are necessary for the recreational activities of the general public. They include parks for walking and cycling, amusement parks etc.
6. Road systems
Road network hierarchy is very important. The efficiency of any town is measured by the layout of its roads. A nicely designed road system puts a great impression in the minds of people, especially the visitors to the town. The provision of a faulty road system in the initial stages of town formation proves to be too difficult and costly to repair or to re-arrange in future.
7. Transport facilities
The town should be provided with suitable transport facilities so that there is minimum loss of time from place of work to the place of residence. Efficiency in transport facilities includes both public and private networks. Public transportation network includes access to buses, trains, trams and trolleybuses.
It is evident that a small house if well arranged and planned, looks far more better than a disordered big palace. In a similar way, a town which is properly planned provide people with more comfort and convenience.
The necessity of town planning can very well be appreciated by mentioning the evil situations which a town has to face in the absence of town planning. They are as follows:
1. Defective road system resulting in the formation of narrow streets and lanes
Defective road system is a problem in most countries. It is due to the fact that towns and cities were never planned. They gradually grew with the help of the developers which resulted in bad road network giving rise to bad transportation network.
2. Development of slums and squatter settlements
If land use is not regulated efficiently, it will result in the formation of slums and squatter settlements which will eventually degrade the quality of the life of the citizens.
3. Haphazard location of industries
Industries are generally located away from towns and cities. Hence, industrial zones have to be allotted so that haphazard springing up of industries on unsuitable locations can be avoided.
4. Heavy traffic congestion during the working hours of the day
If the road network is not efficient, it will lead to heavy traffic congestion. Traffic congestion is linked to a lot of other problems.
5. Inadequate open spaces for parks and playgrounds resulting in unhealthy living conditions
This is one big problem in cities. It is very hard to find open spaces in cities. If there are open spaces, they are later on used up for designing more houses and constructing more buildings. This is more common in metropolitan cities and mega cities across the world.
6. Lack of essential amenities like electricity, water supply and drainage
If planning is not done and towns and cities are left to grow on their own, it results in lack of efficient network of amenities like electricity, water supply, sewerage and drainage systems. This results into degraded quality of life.
7. Noisy atmosphere disturbing the peace of city dwellers
When designing towns and cities, population density is taken into consideration. If the population increases beyond the city’s catering capacity, it becomes impossible to maintain good lifestyle standards. Too population gives rise to too much traffic and noise making the city dwellers uncomfortable.
8. Uncontrolled development of the town
Development of town can be controlled if it is zoned efficiently. Uncontrolled town development is bad news for all of us. For a important and obvious reason that we are all aware of; population is growing whereas we have limited land supply. If we don’t make optimum use of land, the resources are bound to get exhausted and we would reach a stage of no return.
9. Unhealthy living conditions; etc
All the above factors mentioned lead to unhealthy living conditions which can be avoided if we give enough emphasis to planning.
The traditional theory of urban origin is generally attributed to Childe. Childe put forth a theory that urban centres were a result of agricultural change. People as food gatherers advanced to become farmers. Domestication of animals and cultivation of land created villages. Soon, surplus food production was achieved. This allowed some of the people to develop other professions. Priests, craftsmen and merchants were born. However, other scholars contend that it is doubtful that surplus can be attributed as the single factor which caused the emergence of urban settlements . Reasons such as trade and defence have also been used to explain the formation of cities. For thousands of years, cities were very simple although they rarely served single purposes. Instead, they supported a range of activities. Housing, commercial buildings, government offices and warehouses formed the built environment of the city. Pedestrian movement limited the size of the city. Clear differentiation between urban and rural existed, often because of a city wall. However, within, a city contained social distinctions in terms of class, race and religion. Urbanization took place at different chronological periods. The factors influencing urbanization were also different. The variation in influencing factors and historical circumstance gave rise to different urban forms in different parts of the world. The evolution of the urban pattern of Indian cities is divided into the social pattern and the built form.
The growth of medium sized towns (with a population ranging from 20,000 to less than 100,000) in India was subjected to a detailed analysis. The basic premise was that growth behaviour of this group of towns, rather of cities or small towns, was a sensitive index to decentralisation of the urban process as well as to a balanced development of a region.
It was discovered that growth rate of these towns was not just moderate; it was moderate to rapid. This signified that medium sized towns were more akin to cities than to small towns in respect of growth pattern.
Among the various factors affecting growth, location of these towns in a particular region was discerned as more critical than their functions or relative size. Their growth was distinctly fast in areas with comparatively low population density, wide spacing of towns and new developmental activities. Here these towns were generally the biggest in their sub regional context. The growth behaviour of medium sized towns did confirm dispersal of urbanisation but lack of any consistent relationship between their growth rate and development level of different areas was not in conformity with the hypothesis.
Land use
Land use is commonly defined as a series of operations on land, carried out by humans, with the intention to obtain products and/or benefits through using land resources.
Land cover is commonly defined as the vegetation (natural or planted) or man-made constructions (buildings, etc.) which occur on the earth surface. Water, ice, bare rock, sand and similar surfaces also count as land cover.
Land use and land cover have some fundamental differences. Land use refers to the purpose the land serves, for example, recreation, wildlife habitat or agriculture; it does not describe the surface cover on the ground. For example, a recreational land use could occur in a forest, shrub land, grasslands or on manicured lawns.
Land cover refers to the surface cover on the ground, whether vegetation, urban infrastructure, water, bare soil or other; it does not describe the use of land, and the use of land may be different for lands with the same cover type. For instance, a land cover type of forest may be used for timber production, wildlife management or recreation; it might be private land, a protected watershed or a popular state park.
In short, land use indicates how people are using the land, whereas land cover indicates the physical land type. Both types of data are most often obtained from analysis of either satellite or aerial images.
Principles and objects of zoning
The main principle of use zoning is to divide the city into different zones, in correct location with respect to the others.
- It avoids the encroachment of one zone upon another adjoining it.
- Utilization of each zone according to the purpose for which it is allocated.
- Factories and industries on the residential areas can be completely avoided.
- This zone provides open spaces, privacy and good health for the inhabitants of the town.
- It results into stabilization of land values.
- It provides better traffic facilities, water lines, sewer lines and use of other public utility and amenities in an efficient way.
Advantages of zoning
- Zoning can protect and enhance property values.
- Zoning can help to implement the community goals and objectives of a comprehensive plan.
- Zoning can conserve existing neighbour hoods.
- Zoning can preserve existing structures.
- Zoning can prevent the mixing of incompatible land uses (such as erotic dance clubs and schools).
- Zoning can allow potential nuisance uses to be located away from residential neighbour hoods or other sensitive areas.
- Zoning can provide for better lot arrangement. Zoning can protect recreational areas and open space.
- Zoning can conserve environmentally sensitive areas.
- Zoning can insure the availability of an adequate number of parking spaces.
Cost reduction through adhoc methods
Foundation
- Normally the foundation cost comes to about 10 to 15% of the total building and usually foundation depth of 3 to 4 ft. Is adopted for single or double store building and also the concrete bed of (15 Cms.) is used for the foundation which could be avoided.
- It is recommended to adopt a foundation depth of 2 ft.(0.6m) for normal soil like gravely soil, red soils etc., and use the un-coursed rubble masonry with the bond stones and good packing. Similarly the foundation width is rationalized to 2 ft.(0.6m).To avoid cracks formation in foundation the masonry shall be thoroughly packed with cement mortar of 1:8 boulders and bond stones at regular intervals.
- It is further suggested adopt arch foundation in ordinary soil for effecting reduction in construction cost up to 40%.This kind of foundation will help in bridging the loose pockets of soil which occurs along the foundation.
- In the case black cotton and other soft soils it is recommend to use under ream pile foundation which saves about 20 to 25% in cost over the conventional method of construction.
Plinth
- It is suggested to adopt 1 ft. Height above ground level for the plinth and may be constructed with a cement mortar of 1:6. The plinth slab of 4 to 6″ which is normally adopted can be avoided and in its place brick on edge can be used for reducing the cost. By adopting this procedure the cost of plinth foundation can be reduced by about 35 to 50%.It is necessary to take precaution of providing impervious blanket like concrete slabs or stone slabs all round the building for enabling to reduce erosion of soil and thereby avoiding exposure of foundation surface and crack formation.
Walling
- Wall thickness of 6 to 9″ is recommended for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is suggested to use burnt bricks which are immersed in water for 24 hours and then shall be used for the walls
Rat – trap bond wall
- It is a cavity wall construction with added advantage of thermal comfort and reduction in the quantity of bricks required for masonry work. By adopting this method of bonding of brick masonry compared to traditional English or Flemish bond masonry, it is possible to reduce in the material cost of bricks by 25% and about 10to 15% in the masonry cost. By adopting rat-trap bond method one can create aesthetically pleasing wall surface and plastering can be avoided.
Concrete block walling
- In view of high energy consumption by burnt brick it is suggested to use concrete block (block hollow and solid) which consumes about only 1/3 of the energy of the burnt bricks in its production. By using concrete block masonry the wall thickness can be reduced from 20 cms to 15 Cms. Concrete block masonry saves mortar consumption, speedy construction of wall resulting in higher output of labour, plastering can be avoided thereby an overall saving of 10 to 25% can be achieved.
Soil cement block technology
- It is an alternative method of construction of walls using soil cement blocks in place of burnt bricks masonry. It is an energy efficient method of construction where soil mixed with 5% and above cement and pressed in hand operated machine and cured well and then used in the masonry. This masonry doesn’t require plastering on both sides of the wall. The overall economy that could be achieved with the soil cement technology is about 15 to 20% compared to conventional method of construction.
Doors and windows
- It is suggested not to use wood for doors and windows and in its place concrete or steel section frames shall be used for achieving saving in cost up to 30 to 40%.Similiarly for shutters commercially available block boards, fibre or wooden practical boards etc., shall be used for reducing the cost by about 25%.By adopting brick jelly work and precast components effective ventilation could be provided to the building and also the construction cost could be saved up to 50% over the window components.
Lintals and Chajjas
- The traditional R.C.C. Lintels which are costly can be replaced by brick arches for small spans and save construction cost up to 30 to 40% over the traditional method of construction. By adopting arches of different shapes a good architectural pleasing appearance can be given to the external wall surfaces of the brick masonry.
Roofing
- Normally(12.5 cms) thick R.C.C. Slabs is used for roofing of residential buildings. By adopting rationally designed in situ construction practices like filler slab and precast elements the construction cost of roofing can be reduced by about 20 to 25%.
Filler slabs
- They are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc. These filler materials are so placed as not to compromise structural strength, result in replacing unwanted and nonfunctional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster.
Finishing Work
- The cost of finishing items like sanitary, electricity, painting etc., varies depending upon the type and quality of products used in the building and its cost reduction is left to the individual choice and liking.
- The formation of slum is a very slow process and extreme care should be exercised by the authority to prevent the springing up of new slums in the town.
- Some of the important measures which can be taken to effectively prevent the slum formation.
Cheap Housing
- Sufficient no of cheap housing should be made available to the poor people.
Compulsion To Employers
- The employer of a good number of labourers may be compelled or forced to provide housing accommodation for their staff.
Construction of Buildings
- Certain rules and regulations may be framed and strictly enforced to restrict the coming up of buildings of subnormal standards
Maintenance And Repair
- The responsibility of maintenance and carrying out repair should be fixed and defined in housing codes or acts. It then becomes the duty of landlord or tenant to keep existing building in a good condition.
Social Education
- It is possible to check the growth of slums by carrying out effective social education of the slum dwellers, the social education makes the slum dweller conscious of the evils of the slum, and a great improvement in the living standard of slum dwellers could be achieved
Unauthorized Construction
- It is absolute necessary to arrest immediately the unauthorized construction in the form of huts and temporary structures on vacant piece of land.
- The authorities concerned should take drastic action in demolishing and removing such unauthorized construction.
FSI stands for Floor Space Index also known as Floor Area Ratio (FAR). FSI means the ratio between the area of a covered floor (Built up Area) to the area of that plot (land) on which a building stands.
It is calculated by dividing the total covered built-up area on all floors of a building by the area of the plot it stands on. For instance, if you have 1,000 square feet of land on which you want to build a residential or commercial building and the FSI in your locality is 1.5, then you could build up to 1,500 sq.
