Showing posts from October, 2019


WAFFLE SLAB A waffle slab is a concrete slab made of reinforced cement concrete with concrete ribs which are running in two directions. It can be shown from below side and slab has a plain top. Due to the underneath ribs, It is also called ribbed slab. Waffle slab are preferred for longer span which are greater than 12 m. They are much stronger than flat slabs, flat slabs with drop panels, two-way slabs, one-way slabs, and one-way joist slabs. A waffle slab is flat on the top. The top portion of the slab having a thickness of 100 to 120 mm. Below portion of the slab is made of ribs which are intersected to each other. The thickness of these ribs are generally 100 to 200 mm and overall depth of slab is 300 mm to 600 mm Dependent on the span of slab. These ribs create small square blocks. These square blocks has sized of 600 to 1200 mm depending on design. Sometimes the ribs creates triangular blocks.  The ribs of waffle slab are formed by the ready made mould, on which the con


Water is an important natural resource and the need of water is very necessary for organisms to live. It is very important for human survival and existence. We use water for drinking, irrigation, industry, transport and for the production of hydro-electricity. Water is a cyclic resource which can be used again and again after cleaning. The best way to conserve water is its rational use and more accumulation of water from rainfall. Rain water harvesting: Rain water harvesting is one of the most effective methods of water management and water conservation. It is the term used to indicate the collection and storage of rain water used for human, animals and plant needs. It involves collection and storage of rain water at surface or in sub-surface aquifer, before it is lost as surface run off. Needs of rain water harvesting : 1. To overcome the inadequacy of surface water to meet the demands of people.  2. To stop the declination in ground water levels.  3. To enhance availabil


1. Amenities : Amenities means roads, streets, open spaces, parks, recreational grounds, play grounds, gardens, water supply, electric supply,street lighting, drainage, sewerage, public works and other utilities, communication network, surface and convenience. 2. Amusement park : A large outdoor area with fairground rides, refreshments, games of chance or skill and other entertainments. 3. Atrium : It is also called plural atria. It means an unobstructed, multi storied open space within a building that covered from top with light weight or glazed roof. 4. Banquet hall : It means a room or an enclosed space or building for the purpose of hosting any social events or ceremonies like marriage, reception, party etc. With accompanying food and beverages. 5. Basement : I means the lower storey of a building having at least half of the clear floor height of the basement or cellar below average ground level. 6. Botanical garden : It is a garden or an open space of land often w


The following important tests are carried out for normal setting of portland cement : 1. Fineness test : This test is conducted to check the proper grinding of cement. The fineness of cement is rested either by sieve method or air permeability method. The percentage of residue left after sieving good portland cement in 90 micron IS(Indian standard) sieve should not exceed 10%. A good portland cement should not have specific surface less than 2.25, if found by air permeability method. 2. Consistency test : This test is conducted to determine the percentage of water required for preparing cement paste of standard consistency. The consistency test is performed with the help of vicat's plunger apparatus which determines the initial and final setting time and normal consistency of portland cement. The initial setting time of ordinary and rapid hardening cement should not be less than 30 minutes. The final setting time of ordinary and rapid hardening cement should not


PLASTERING WORK Plastering work is a process of covering the rough surfaces or unfinished surfaces like walls, ceilings, column and other building components with thin coat of cement mortar or other material to form a smooth and finished surface and gives an aesthetic appearance. It increases the durability of surface. Purpose of plastering : 1.   It provides flat, smooth and even surface. 2. It makes masonry or AAC block wall more durable. 3. It protects inner surface from atmospheric conditions. 4. It can resist the cracks which may develop in wall. 5. It provides suitable surface for painting or any other aspect. 6. It prevents the penetration of water. 7. It provides hard surface which do not scratched by the sharp things. Classification of plaster It may be classified based on three parameters which are given below. 1. Based on material 2. Based on Finishes 3. Based on coat 1. Based on material : Lime plaster : It involves the sand and


TOP THINGS THAT MUST KNOW BY CIVIL SITE ENGINEERS : 1. Minimum bars for square column is 4 nos and 6 nos for circular column. 2. Free fall of concrete is allowed maximum to 1.5 m height. 3. Appropriate water to cement ratio should be around 0.4 to 0.5. 4. Electrical conduits shall not run in column. 5. First class bricks should not absorb water more than 15% of its dry weight. 6.Minimum compressive strength of bricks is 3.5 N/mm2. 7. In steel reinforcement binding wire required is 8 kg per MT. 8. PH value of water for construction purposes should not be less than 6. 9. Initial and final setting time of cement is respectively 30 minutes and 600 minutes. 10. Curing days for ordinary portlnd cement should be minimum 10 days. 11. To find wieght of steel per meter, d2/162 formula has been used. 12.Minimum thickness of slab is 125 mm. 13. Minimum 3 specimens of cubes needed to determine average compressive strength of concrete. 14. Lapping is not allowed for the


Fiberboard is a type of engineering wood which is manufactured by binding or fixing the particles, wood fibers or boards of wood together with adhesives by applying the method of pressing or heating.  Types of fiberboard in order of increasing the density include particle board or low density fiberboard (LDF), medium density fiberboard (MDF) and hardboard or high density fiberboard (HDF). What is low density fiberboard or particle board? It is a chip board which is manufactured from wood chips, sawmill shavings and other type of sawdust scrap with the help of resins or other suitable binder. The density of LDF is around 500  kg/m³. Advantages : 1. It is a lightest and cheapest among fiberboards. 2. It has thermo-acoustic insulation properties, so they are very useful in speakers and in false ceiling of auditoriums, theaters etc. 3. It is eco-friendly material as it is uses wood waste such as sawdust, wooden shavings and wood chips. It does not get distort easily. Disad


ADMIXTURES Plasticizers Superplasticizers Retarders and retarding plasticizers Accelerators and accelerating plasticizers Air-entraining admixtures Damp-proofing and waterproofing admixtures Gas forming admixtures Air-detraining admixtures Alkali-aggregate expansion inhibiting admixtures Workability admixtures Grouting admixtures Corrosion inhibiting admixtures Bonding admixtures Fungicidal, Germicidal, Insecticidal admixtures Colouring admixtures CHEMICALS Concrete curing compounds Polymer bonding agent Mould releasing agents Polymer modified mortar for repair and maintenance Protective and decorative coatings Installation aids Floor hardner and dust proofers Non-shrink high strength grout Surface retarders Bond-aid for plastering Ready to use plaster Guiniting chemical Some water proofing chemicals  Integral water-proofing compounds Membrane forming coatings Polymer modified mineral slurry coatings Protective and decorative coatings


SOUNDNESS OF AGGREGATE Soundness refers to the ability of aggregate to resist excessive changes in volume a s a result of changes in physical conditions. These physical conditions that affect the soundness of aggregate are the freezing the t hawing, variation in temperature, alternate wetting and drying under normal conditions and wetting and drying in salt water. Aggregates which are porous, weak and containing any undesirable extraneous matters undergo more than the specified amount of volume change is said to be unsound aggregates. If concrete is liable to be exposed to the action of frost, the coarse and fine aggregate which are going To be used should be subjected to soundness test. The soundness test consists of alternative immersion of carefully graded and weighed test sample in a solution of sodium or magnesium sulphate and oven drying it under specified conditions.The accumulation and growth of salt crystals in the pores of the particles is thought to produce disru


INTRODUCTION A brick is rectangular in shape and of size that can be conveniently handled with one hand. Brick may be made of burnt clay or mixture of sand and lime or of Portland cement concrete. Clay bricks are commonly used since these are economical and easily available. The length, width and height of a brick are interrelated as below: Length of brick = 2 × width of brick + thickness of mortar Height of brick = width of brick Size of a standard brick (also known as modular brick) should be 19 × 9 × 9 cm and 19 × 9 × 4 cm. When placed in masonry the 19 × 9 × 9 cm brick with mortar becomes 20 × 10 × 10 cm. However, the bricks available in most part of the country still are 9" × 4.5"× 3" and are known as field bricks. Weight of such a brick is 3.0 kg. An indent on top of brick called frog, 1–2 cm deep. The size of frog should be 10 × 4 × 1 cm. The purpose of providing frog is to form a key for holding the mortar and therefore, the bricks are laid with fr


Pipe fittings are an important component of the plumbing system. In plumbing, many types of fixtures are joined with the help of various types of material as per the requirement. Fittings are fixed in the plumbing system to join straight pipes or any section of tubes. We can say that the water-supply fittings like elbow, tee, socket, reducer, etc., are fitted to change the direction of flow, distribute the water supply from the main pipe to other pipes of equal size or lower size, etc. Any part used in connection with water supply, distribution, measurement, controlling, use and disposal of water is known as a pipe fittings. Type of Fittings  1. Collar  2. Elbow  3. Gasket  4. Union  5. Reducer  6. Tee  7. Nipple  8. Trap  9. Cross 10. Offset 11. Coupling 12. Adaptors  1. Collar :  While joining two pipes in the same length, collar is used. Collar is fitted in the end of pipe. 2. Elbow :  It is installed at the time of joining two pipes. With the help


METHODS TO IMPROVE THE BEARING CAPACITY OF SOIL When the soil is not sufficient strong to bear the loads coming from foundation, then we have to attempt some steps to make soil more stronger and stiffer to carry the loads on itself. The following methods can be used as per suitable on soil condition at site for improving the bearing capacity of soil. 1. By going to more deep 2. By desiccation of soil  3. By compaction of soil 4. By restricting the soil 5. By replacement of weak soil 6. By use of grout material  7. By mixing of granular materials 8. By chemical treatment 1.  By going to more deep :  Due to overburden at deep depth, The bearing capacity of soil is more because the soil is more compacted at deeper depth. Hence it shows higher bearing capacity than upper ground.  This is applicable only on cohessionless soil. This method can not be used where the soil becomes more wet or moist at depth. This methods has a limited use because with increasing the depth, co


FLOOR SPACE INDEX (F.S.I) It is the ratio of the gross floor area of the all floors including area of all walls, except areas specifically exempted under these regulations to the total area of the plot. FSI x Plot area = Total Built up area For example, If you have a 1000 sq.m plot with 30 ft wide road and permissible FSI is you can make premium avail FSI of 20 %,      1.8 x 20% x 1000 = 2160 sq.m The following spaces shall not be counted towards computation of F.S.I. 1. Parking spaces without any enclosures and partitions of any kind, with clear height of 2.4 mts. and in case of slabs with beams, height should not exceeds 2.8 mts. 2. Spaces of hollow plinth with maximum clear height of 2.8 mts in addition to depth of beams as per structural requirements in residential buildings only (not even in mixed development) at ground level without any enclosures/walls and partitions in any form excluding shear walls as per structural requirements. 3. Interior open spaces


DIFFERENT TYPES OF AREA 1. Plot area : The area which is enclosed by surrounded boundary lines is called plot area. in other words, the total area covered within your definite premises is called plot area. 2. Built up area : The area which is covered to construct the building at the floor level of building is called built up area. It is also known as plinth area.For example, A building constructed on 100 sq.m area Hence, the 100 sq.m area is built up area or plinth area of building. Below mention areas are come under the built up area. Bedrooms, living rooms, hall, balcony, kitchen, bathroom, utility areas, shaft areas, staircase, terrace, veranda, podium, atrium, corridors and wall thickness etc. 3. Super built up area : The area which comprises the built up area which is total area covered by building and other amenities which are out side the building like Garden, swimming pool, parking, gym playground, club house etc. 4. Carpet area : The area on which you can