BTAP
Excavation or earth work Foundation Concreting work or R.C.C work Masonry work Plastering Waterproofing Painting Doors and window work and steel fabrication work Plumbing Electric fitting work. Flooring Painting. Group A- Residential building Group B - Educational building Group C- Institutional building Group D- Assembly building Group E-Business building Group F-Mercantile building Group G - Industrial building Group H-Storage building Group I- Hazardous building A part of the structure lying below the ground surface such as foundation of any type is known as substructures. Hence, the component of substructure is any type of foundation. Foundation: The term foundation indicates the entire substructural unit which supports the superstructure. Thus, in broader sense, foundation includes a transmitting medium in the form of a pedestal, footing, pile system, pier, caisson and the supporting foundation bed. The transmitting medium is generally constructed in reinforced cement concrete and the foundation bed is generally in the form of sound bedrock or weathered rock or soil. The function of foundation is not merely to support the weight of superstructure. In turn the foundation serves many purposes as enlisted below. To distribute load of the entire structure over a wide spread area to prevent it from any movement. To load the underlying bearing surface uniformly to prevent any unequal settlement of the substructure. To prevent any lateral escape of the supporting material as it will endanger the structure. To increase the stability of the structure as a whole to prevent it from sliding or overturning. To secure a level and firm natural bed for laying the masonry courses. Superstructure denotes part of the structure lying above the ground surface. In context of buildings various parts like walls, roof, doors, windows and flooring constitute the superstructure. The part of the structure lying above the ground and below the ground floor level is called as plinth. The superstructure is designed to cater for various loads acting on the structure, which are then transmitted to the underlying soil via the substructure. Following are the various components of superstructure of building: Plinth Floor Wall Column Beam Roof Door and Windows Lintel Sill Staircase Parapet Availability of stone: The stone used for masonry should be easily available from nearby sources. Ease of working: The stone should permit easy dressing and shaping to facilitate working on it easily. Appearance: The appearance of the stone should be attractive and colour should be uniform. Strength: The crushing strength of stone should permit the use of stone in wall masonry. Polishing characteristics: The stone when polished should look attractive with shining texture. Course: A course is a horizontal layer of brick in a wall. Joint: It is the junction of two or more bricks in a wall construction. Header: It is a brick which lies with its greatest length at right angles to the face of the masonry work. Stretcher: It is a brick which lies with its longest side parallel to the face of the masonry work. Frog: A small depression created purposely on one side of brick is called 'frog'. Bed: The bottom surface of the brick when it is laid flat is termed as bed. A good brick masonry should utilise bricks which are sound, hard, well burnt and tough with uniform colour, shape and size. The bricks should be compact, homogeneous, free from holes, cracks, flaws, air bubbles and stone lumps. These bricks should be properly soaked in water for atleast two hours before use. In the brickwork, the bricks should be laid on their beds with the frogs pointing upwards. The brick courses should be laid truly horizontal and should have truly vertical joints. The brick walls should be raised uniformly with proper bond. The height of brick masonry construction in a day should not exceed 1.5 m. Finished brickwork is cured for a period of 1 to 2 weeks. A good brick should have a fine, compact and uniform texture. When struck with hammer, it should give a good metallic sound. When dropped from a height of about 1 meter on another brick, it should not break. A good brickwork should have maximum compressive strength and durability. A good brickwork should have maximum resistance to weathering. A good brickwork should be fire resistant. This is most common and popular bond and is used for wall thickness ranging from 20 cm. and above. It consists of equal balancing of headers and stretchers in the wall, that is headers and stretchers are arranged in alternate courses. English bond construction requires the following points to be kept in view : A queen closer must be provided after the quoin header. A header course should never start with a queen closer. Continuous vertical joints should not be allowed. The joints in the header course should be made thinner than those in the stretcher course. This is because of the fact that the number of vertical joints in the stretcher course are half of the number of joints in the header course. In the stretcher course, the stretchers should have a minimum lap of (1/4)th their length over the headers. The bricks should be well burnt, reddish in colour, sound and hard and should have uniform shape and size. Bricks should be as per the specifications. Bricks should be soaked in the water before using them into the masonry work. Use of brick bats should not be more. The bricks should be neatly and properly laid on mortar. Frog should be on the top surface. The brick masonry work should be done in proper bond. The brick work should be perfectly in level. Hold fasts for door should be properly inserted into the masonry work. The brick work used should be truly in plumb. The motoar used should be as per specification and fresh. Construction joints should be provided after every 30 m to 50 m length of wall. After completion of brickwork, a proper curing at least seven days should be done to the masonry work for getting required strength. Note that, if mud mortar or lime mortar is used, then bricks should not be soaked into the water before using them into the masonry work. Bricks are soaked into the water only when cement mortar is used. The moulds made up from some rigid material such as timber or steel plates in which concrete is placed and in which it is harden are called "formwork". Formwork is generally made from inexpensive timber planks. These are joined to form the required moulds of slab, beams, columns, foundations etc. Steel formwork is used in the form of plates which can be bolted together to form moulds of different shapes and size according to the dimension of structural members. Formwork consists of two parts: The mould or platform is built by joining the planks together by nailing. The gaps between the planks are plugged or sealed so that the cement slurry should not leak through them. It is made up of timber poles supporting the mould at various points. For a large slab, the formwork is supported on timber poles with double wedge arrangement at the lower end so that individual poles can be lowered or raised by hammering of the wedges and the entire plank supporting the slab can be levelled and made horizontal. For columns, the centering consists of inclined supporting poles or struts,this is known as shoring. The shoring is also easily adjustable so that the plank can be made perfectly vertical. The verticality of the plank is checked by plumb bob. Thus for horizontal planks, vertical poles are used, and for inclined or vertical planks, struts of various sizes are used as shoring. The setting of concrete should not occur before it reaches the formwork. The concrete should not get segregated due to transportation. Bleeding should not occur. There should not be a large time gap between two loads of concrete received at the formwork. The reinforcement should be checked. There should be sufficient gap between reinforcement and formwork to provide required cover. Concrete should not be dropped from great height. i.e. more than 1 meter. Concrete should be placed uniformly in all formwork. Placing a heap of concrete at one place and then dragging it to fill the formwork is not a good practice. Concrete should reach all the corners of formwork. In case of narrow sections or columns with large no. of lateral getting stuck on reinforcement should be looked for and removed. Concrete is a drab material and its colour and surface texture do not offer architectural beauty Hence many times when concrete is exposed to view, finishing must be done. If proper care is not taken while concreting it may posses cracks, due to improper construction poor construction joints, patching of honey combed structure, damaged area which is not pleasing to eye and hence finishing is necessary to keep concrete surface smooth, asthetic and free from irregularities The purpose of finishing is two fold: Having correct slope. Having smooth polished surface. Following are the different types of finishing methods: Surface treatment Exposed aggregate finish Applied finish Coloured finish Curing is necessary for continuation of hydration reaction which gives concrete its strength. It is necessary to avoid drying of concrete till full strength is achieved. To dissipate the heat of hydration. It reduces shrinkage in concrete. It prevents waterloss by evaporation and helps in maintaining process of hydration. Slip form construction is an advanced method for building having the large towers or bridges. The name refers to the moving form the concrete is poured into, which moves along the project as the previously poured concrete hardens behind it. The technique of slip form construction has also been applied to road construction. The slip form technique was in use by the early 20th century for building silos and grain elevators. A notable use of the method was the 'Skylon Tower' in Niagara falls, Ontario which was completed in 1965. The technique was soon utilized to construct the "Inco Superstack in Sudbury, Ontario and the CN Tower in Toronto. It is the most common method for construction of all buildings in Australia. Use: Slip formwork is widely used for constructing the large towers or bridges. It is also used for constructing the silos and grain elevators. Underpinning is the process of providing new foundation below the existing foundation without damaging the stability of existing structure. Underpinning may be required to meet the following requirements: If deep foundation to be constructed adjoining to a building having shallow foundation, the shallow foundation may face some problems and may need strengthening. To strengthen existing foundation which has settled and caused cracks in the wall. If the height of existing building is to be increased and existing foundation, if unable to bear increased load, may require strengthening. If basement is to be provided to the existing building and if depth and strength of existing foundation is insufficient, then existing foundation may need strengthening. When the height of construction is more than 1.5 m, workmen need some platform on which can stand safely, keep necessary materials of construction and carry on the construction, etc These temporary structure or platform constructed very close to the wall, is in the form of tiss or steel framework, commonly called scaffolding. The height of scaffolding goes on increasing as the height of construction increases. Purpose of Scaffolding: Provides a platform to stand safely and carry on the constructions. Provides platform to keep necessary materials of construction, tools such as bricks, mortor, trowel, plumb, etc. Scaffolding is also needed for the repairs or even demolition of a building. Standards: These are vertical members of scaffolding, supported on the ground or drum or embedded into the ground. Ledgers: These are horizontal members, running parallel to the wall and perpendicular to the standards. Braces: These are diagonal members fixed on standards. Putlogs: These members are placed on ledgers at right angles to the walls, with one end supported on ledgers and other end on the wall. Boarding or planks: These are the horizontal platform for supporting men, materials and appliances, these are supported on the putlogs. Guard boards: To guard against materials, the boards are provided at the working level called guard boards. Toe board: These are boards placed parallel to the ledgers and used for protection at the level of working platform. Acid resistant bricks Engineering bricks Silica bricks Refractory bricks Sand-lime bricks Blue bricks Coloured bricks Perforated bricks Fire bricks Hollow bricks or Hollow block
Unit-1
Introduction to Building Construction and Masonry
Q1) What are the various basic construction practices are being done in the construction processes?
A1) Following are the various basic construction practices are being done in the construction processes:
Q2) What is the definition of ‘Building’?
A2) As per the National Building Code of India (SP:7-1970); building defines, "as any structure for whatsoever purpose and of whatsoever materials constructed and every part thereof whether used as human habitation or not and includes foundation, plinth, walls, floor, roofs, chimneys, plumbing and building services: fixed platforms, varandah, balcony, cornice or projection, part of a building or any things affixed there to or any wall enclosing or intended to enclose any land or space and signs and outdoor display structures."
Q3) What are the different types of building as per National Building Code?
A3) According to the NBC of India i.e. National building code of India, buildings are classified into various groups which are based on occupancy, are mentioned as follows:
Q4) What do you mean by ‘Substructure’?
A4)
Q5) What are the functions of foundation?
A5) Functions of foundation are as follows:
Q6) What do you mean by ‘Superstructure’?
A6)
Q7) On what basis, Selection of stone masonary work depends?
A7) The selection of stone for masonry depends upon :
Q8) What are the different terms used in Brick masonary?
A8) Following are the different terms used in brick masonary:
Q9) What are the Characteristics of Good Building Bricks?
A9) Following points gives the characteristics of good brickwork:
Q10) What is English Bond?
A10)
Q11) What are the precautions considered in brickwork?
A11) Following precautions are considered during brickwork:
Q12) What is Formwork?
A12)
1. Mould or platform:
2. Support system or centering:
Q13) What Precautions to be Taken During Transportation and Placing of Concrete in Formwork?
A13) Following precautions should be taken while transporting the concrete:
Following Precautions Should be Taken During Placing of Concrete in Formwork:
Q14) What is mean by finishing of concrete?
A14)
Q15 What is the necessity of curing of concrete?
A15) Necessity of curing of concrete is required for following reasons:
Q16) What is slip formwork?
A16)
Q17) What is Underpinning?
A17)
Q18) What is Scaffolding?
A18)
Q19 What are the Components of Scaffolding?
A19) Scaffolding consists of the following components:
Q20) Enlist the different types of bricks?
A20)
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