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Name of the scheme:- construction of Recreation Cum Health Club at Green Belt Park in Housing Colony Channi Himmat, Jammu. Authority :- Housing Department. History :- The Channi Himmat Housing Colony located in the East of Jammu city spread over an area of 2840 kanals having 3360 number of plots of various sizes established in early eighties. This colony consists of eight sectors & every sector is provided with well developed basic infrastructure & amenities like network of roads and drainage system. This colony is having total road length of 40.29 kms as a whole. Besides the colony is having a networks of parks at appropriate locations and there is also availability of land which has been reserved for schools, bus stand shelters and the community hall. PROPOSAL It is proposed to construct recreation Cum Health Club together with swimming pool fully furnished with equipments required for Gym. It is also proposed for providing services/ facilities like restaurant, party hall, sauna room,steam room,Jacuzzi gym and other related facilities. BRIEF SPECIFICATIONS i. Founda
CONSTRUCTION OF RECREATION CUM HEALTH CLUB A SIX MONTHS INDUSTRIAL TRAINING REPORT IN THE PARTIAL FULLFILMENT FOR THE AWARD OF THE DEGREE OF BACHELOR OF TECHNOLOGY IN CIVIL ENGINEERING SUBMITTED BY ASHISH PAUL SINGH KALA 100610101515 Rayat-Bahra Institute of Engineering & Nano Technology Hoshiarpur ACKNOWLEDGEMENT I take this opportunity to extend our sincere thanks to Er. AMANPREET KAUR HOD CIVIL DEPARTMENT AT RAYAT-BAHRA INSTITUTE OF ENGINEERING & NANO TECHNOLOGY HOSHIARPUR. for providing us with this invaluable opportunity to undertake our training report in the department. I would like to a special thanks for my training supervisor POOJA WAZIR, AEE J&K HOUSING BOARD JAMMU, who helped me in field knowledge i.e. about constructon of building works & drawings.. DECLARATION BY CANDIDATE I, hereby, certify that this work, on “CONSTRUCTION OF RECREATION CUM HEALTH CLUB”, is presented in partial fulfillment for the award of degree of B.Tech (CIVIL) at Rayat-Bahra Institute of Engineering & Nano Technology, Hoshiarpur. This report is an authentic record of my own work carried out during a period from DEC 2013 to JUNE 2014 under the supervision of “POOJA WAZIR”. The matter presented in this report has not been submitted by me in any other University / Institute for the award of B.Tech Degree. Signature of the Student(s) Signature of Guide INDEX Introduction. Proposals/ works in progress. Theory of Reinforcing concrete & Method of design. Salient Features of RCC Structures. Design of RCC Beams (Practical Rules) . Design of Slab (Practical Rules). Components of Building. Planning & Design of Building. Sequenece of Structure work INTRODUCTION J&K Housing Board has been established under the provisions of J&K Housing Board Act 1976. The primary task of the board is to provide 1. Affordable shelter for all. 2. Development of housing colonies in urban as well as in rural areas of the state. 3. Construction of flats under self financing schemes. 4. Construction of commercial centres in different housing colonies. 5. Construction of office complexes of various departments (J&K GOVT). 6. Works of other departments entrusted to this organization like hospitals, degree colleges etc. PROPOSALS/WORKS IN PROGRESS 1. Proposal for acquisition of land for below noted housing colonies is under process :- 1. Mujgund, Srinagar 2700 kanals of land. 2. Meencharkhan, jammu 3000 kanals of land. 3. Batalwallian, udhampur 1000 kanals of land. 2. Housing colony at Kathua on a land of 674 kanals comprising of has been planned. Presently, the road network, electric installation in the form of Poles and conductors together with OH tanks and water pipe line network have been taken up. 3. Development of one km long Green Belt Park at Housing Colony, Channi Himmat, Jammu is in progress, subject to availability of funds released by the Government (H&UD) annually under the head “Improvement of Existing Colonies”. 4. Housing colony at Reasi developed and 57 plots allotted to public. 5. J&K Housing Board is State Nodal Agency for Rajiv Awas Yojna in J&K state. Ministry of Housing & Urban Poverty Alleviation has sanctioned the implementation of the scheme in 6 cities across the state namely Jammu, Kathua, Udhampur, Srinagar, Baramulla & Anantnag. Survey work including GIS/MIS taken up and already completed in Kathua and work for Udhampur is in progress at present. After the completion of survey work, dwelling units for the identified beneficiaries shall be constructed to be funded by Ministry of Housing & Urban Poverty Alleviation. 6. 45 kanals of land acquired at Humhama, on Airport Road Srinagar and possession taken. It is proposed to construct 3 bed room duplex type flats. THEORY OF REINFORCING CONCRETE & METHOD OF DESIGN The use of plain concrete in structural works is limited by the fact that the tensile strength of concrete is only about one tenth of its compressive strength. Hence, a beam of plain concrete will fail in the bottom when the top portion can still take ten times the stress. By inserting steel bars in the bottom of the beam to take the tensile stress, the beam is made ten times as strong as plain beam. Therefore, combination of steel and concrete makes structure not only strong but also stable. Method of Design:- Two methods of design for reinforced concrete structures are used, the working stress or elastic method and the limit state or load factor or the ultimate load method. In working stress method, the design is based on working loads and the criterion for the strength of structure is its capacity to sustain the loads and forces imposed on it. The limit state method of design is based on determination of load at which a structure fails and a certain factor of safety is adopted. Both the methods give somewhat different results. SALIENT FEATURES OF R.C.C STRUCTURES 1. Factor of safety :- Factor of safety is the relation between ultimate strength at failure and permissible stress. 2. Modulus of Elasticity :- It is measure of elastic property of a material and the ratio between the stress caused by an applied load and the resulting strain or deformation. 3. Modular Ratio:- The relation between the modulus of elasticity of reinforcing steel and the modulus of elasticity of concrete is called modular ratio. As there is no relative movement between concrete and steel in a reinforced concrete, the elongation or contraction of both steel and concrete is equal. The modular ratio is proportional to permissible stresses in steel and concrete which work together. In other words the value of modular ratio varies with the modulus of elasticity of steel and concrete respectively. 4. Grades of Concrete:- A set of mix for concrete should be well defined either in terms of the proportion of cement, sand, fine and coarse aggregates or in terms of 28- days compressive strength requirements. The mixes usually used are 1:3:6, 1:2:4, 1:1.5:3, 1:1:2 The 1:3:6 mix is used for mass concreting and the rear sides of dam. The 1:2:4 mix is used for general reinforced concrete work. The 1:1.5:3 mix is used for front faces of dams, water tanks, columns etc. The 1:1:2 mix is used for piles The IS 456:2000 code has recommended that the minimum grade of concrete for plain and reinforced concrete work is M20. DESIGN OF R.C.C BEAM (PRACTICAL RULES) 1. The overall depth of singly reinforced beam shall not be less than one twentieth of the span unless shear and other considerations prevail. The greater the depth of beam less is the steel required and more economical is the beam, but there is limit to hit. 2. The breadth of beam shall normally be two third to one half of the depth but not less than one third of depth. A good rule for breadth is to take three fifth of the depth of the beam. 3. The deflection due to all loads should not normally exceed span/250. 4. The deflection including the effects of temperature, creep and shrinkage occurring after erection of partitions and the application of finishes should not normally exceed span/350 or 20 mm whichever is less. The horizontal clear space between two parallel main reinforcement bars shall not be less than greatest of the following The diameter of the bar if the diameters are equal. The diameter of the larger bar if diameters are unequal. 5mm more than the nominal maximum size of the coarse aggregates used in the concrete. Where needle or immersion vibrators are intended to be used, the horizontal distance between bars of a group may be reduced to two thirds of the nominal maximum size of the coarse aggregate provided that sufficient space is left between groups of bars to enable the vibrator to be immersed. The clear vertical space between two horizontal main reinforcing bars shall normally be 15 mm, the maximum size of coarse aggregate or the maximum size of bar whichever is largest. Bars can also be placed one above the other. Main tensile reinforcement bars in beams shall not be less than 12 mm in diameter DESIGN OF SLAB (PRACTICAL RULES) 1. The overall thickness of slab shall not be less than 7.5cm. 2. The top surface of centering shall be given a camber of 7 mm per metre of span subject to maximum of 4.5 cm. 3. The minimum reinforcement in slabs in either directions shall not be less than 0.15% of the gross cross sectional area of the concrete and which may be 0.12% where high yield strength deformed bar or welded wire fabric are used. 4. The spacing of main tensile bars shall not be more than three times and the distributing bars not more than five times the effective depth or 450 mm whichever is less. 5. The diameter of main tensile reinforcement in slabs shall not be less than one eight of total thickness of the slabs and not less than 6 mm in diameter. 6. In simply supported single span slabs it is not normally necessary to bend up any bars. But in partially fixed condition which are the most common and occur where roof slab are built into walls every third bar shall be bent up, or equivalent separate reinforcement may be provided at the top of the supports for the negative moments. Bent up bars are more economical. In large slabs separate reinforcement over the supports may be necessary. Such bent up bars shall extend a sufficient distance beyond the centre of the support to provide adequate bond. The point at which some of the reinforcement is bent up for negative bending moment at the supports depend upon the point of contraflexure. Stirrups are not used in slabs. 7. Distribution bars also called ‘binders’, ‘crossbars’, ‘temperature reinforcement’, or ‘secondary reinforcement’. The object of these bars is to resist cracks due to temperature and shrinkage stresses, to assist in distributing local loading and to take any bending stresses that may developed. These bars are provided perpendicular to and on top of the main tensile bar in slabs spanning in one direction. Well distributed steel reinforcement reduces the shrinkage and expansion of reinforced concrete. The distributing bars shall be at least 25% of the main tensile bars for roof slabs subject to much temperature changes, where additional bars shall also be provided at the top in thick slabs. In floors transverse reinforcement may be only 10 to 15% of the main bars. The diameter of such bars varies from 5mm to 12 mm, 6 mm to 10 mm bars are more convenient. Distribution bars should not be hooked or bent as hooks will tend to localize the cracks and make the distribution steel non effective. COMPONENTS OF A BUILDING 1) Foundation. 2) Footing 3) Plinth 4) Walls 5) Column 6) Floors 7) Doors,windows & ventilators 8) Stairs 9) Roofs 10) Building finishes Foundation :- A foundation is a structure that transfers load to the ground. TYPES:- SHALLOW FOUNDATION Shallow foundation is, usually, embedded a meter or so. One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. Another common type is the slab-on-grade foundation where the weight of the building is transferred to the soil through a concrete slab placed at the surface. It transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. These foundations are common in residential construction that includes a basement, and in many commercial structures DEEP FOUNDATION A deep foundation is used to transfer a load from a structure through an upper weak layer of soil to a stronger deeper layer of soil. There are different types of deep foundations including helical piles, impact driven piles, drilled shafts, caissons, piers, and earth stabilized columns. The naming conventions for different types of foundations vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete. MAT-SLAB FOUNDATIONS Mat-slab foundations are used to distribute heavy column and wall loads across the entire building area, to lower the contact pressure compared to conventional spread footings. Mat-slab foundations can be constructed near the ground surface, or at the bottom of basements. In high-rise buildings, mat-slab foundations can be several meters thick, with extensive reinforcing to ensure relatively uniform load transfer. FOOTING Under every house is a foundation, and under most foundations are footings. Most of the time we take footings for granted, and usually we can: For typical soils, a common 16- or 20-inch-wide footing can more than handle the relatively light weight of an ordinary house. On the other hand, if you build on soft clay soil or if there's a soft zone under part of your foundation, there can be trouble. A footing that performs well in good soil may not do so well in weak bearing conditions. We don't often see outright failure, but it's not uncommon to see excessive settlement when soil bearing capacity is low. If the whole house settles slowly and evenly, some additional settlement is no big deal; but if settlement is uneven (differential settlement), there could be damage. PLINTH The portion of the building between the ground surrounding the building and the top of the floor immediately above the ground is known as plinth. The level of the surrounding ground is known as formation level or simply ground level and the level of the ground floor of the building is known as plinth level. The plinth height should be such that after proper leveling and grading of the ground adjoining the building (for proper drainage) there is no possibility of the rain water entering the ground floor. The built up covered area measured at the floor level is termed as plinth area. WALLS Walls are provided to enclose or divide the floor space in desired pattern. In addition, walls provide privacy, security and give protection against sun, rain cold and other adverse effects of weather. The division of floor space varies according to the functions required to divide the space in such a manner so as to achieve maximum carpet area and minimum area of circulation. Walls are constructed by use of building units like bricks, stone, concrete blocks (hollow or solid) etc. The building units are bounded together with mortar in horizontal and vertical joints and the construction is termed as masonry. When bricks are used as building units it is known as bricks masonry and stones are used as building units it known as stones masonry. Walls can be dividing in two categories (1) Load bearing walls and (2) Non-load bearing walls A load bearing wall supports its own weights as well as the super-imposed loads transferred to it through floor/roofs. A non-load bearing wall on the other hand carries its own weights and is not designed to carry any super-imposed load from the structure. They are normally provided as partition walls COULMNS A Column is defined as an element used primarily to support axial compressive loads and with a height of at least three times its lateral dimension. A compression member subjected to pure axial load rarely occurs in practice. All columns are subjected to some moment which may be due to accidental eccentricity or due to end restraint imposed by monolithically placed beams or slabs. The strength of a column depends on the strength of the materials, shape and size of the cross-section, length and the degree of positional and directional restraints at its ends. TYPES:- A column may be classified based on different criteria such as: 1) Shape of cross-section, 2) Slenderness ratio, 3) Type of loading, 4) Pattern of lateral reinforcement A column may be rectangular, square, circular or polygon in cross-section. The Code specifies a certain minimum reinforcement bars depending on shape of the column. A column may be classified as short or long column depending on its effective slenderness ratio. The ratio of effective column length to least lateral dimension is referred to as effective slenderness ratio. A short column has a maximum slenderness ratio of 12. Its design is based on the strength of the materials and the applied loads. A long column has a slenderness ratio greater than 12. However, maximum slenderness ratio should not exceed 60. A long column is designed to resist the applied loads plus additional bending moments induced due to its tendency to buckle. A column may be classified as follows based on types of loading: 1) Axially loaded column, 2) A column subjected to axial load and uni-axial bending, and 3) A column subjected to axial load and bi-axial bending A reinforced concrete column can also be classified according to the manner, in which the longitudinal bars are laterally supported, that is, 1) Tied column, and 2) Spiral column. REQUIREMENTS FOR REINFORCEMENT There are two kinds of reinforcement in a column: 1) Longitudinal reinforcement, and 2) Transverse reinforcement The purpose of transverse reinforcement is to hold the vertical bars in position providing lateral support so that individual bars cannot buckle outwards and split the concrete. Transverse reinforcement does not contribute to the strength of a column. LONGITUDINAL REINFORCEMENT 1) The minimum area of cross section of longitudinal bars must be at least 0.8% of the gross-sectional area of the column. 2) In any column that has a larger cross sectional area than that required to support the load, the minimum percentage steel must be based on the area of the concrete required to resist the direct stress not on the actual area. 3) The maximum area of cross section of longitudinal bars must not exceed 6% of the gross cross sectional area of the concrete. Although, it is recommended that the maximum area of steel should not exceed 4% to avoid practical difficulties in placing and compacting of concrete. 4) The bar should not be less than 12 mm in diameter so that it is sufficiently rigid to stand up straight in the column forms during fixing and concreting. 5) The minimum number of longitudinal bars provided in a column must be 4 in rectangular column and 6 in circular column. 6) A reinforced concrete column having helical reinforcement must have at least 6 bars of longitudinal reinforcement within the helical reinforcement. 7) Spacing of longitudinal bars measured along the periphery of a column should not exceed 300 mm. TRANSVERSE REINFORCEMENT Transverse reinforcement may be in the form of lateral ties or spirals. Lateral ties may be in the form of polygonal links with internal angles not exceeding 135 degrees. The ends of the transverse reinforcement should be properly anchored. LATERAL TIES 1) Diameter of the polygonal links should not be less than one-fourth of the diameter of the longitudinal bars, and in no case less than 6 mm. 2) Pitch of the lateral ties should not exceed the following distances: i) The least lateral dimension of the compression member , ii) Sixteen times the smallest diameter of the longitudinal reinforcement bar to be tied, and iii) 300 mm. HELICAL REINFORCEMENT 1) The diameter of the helical reinforcement should not be less than one-fourth of the diameter of the longitudinal bar, and in no case less than 6 mm, 2) If an increased load on the column on the strength of the helical reinforcement is allowed for, its pitch should not exceed the following distances: 75 mm One-sixth of the core diameter of the column The pitch should not be less than following distances: 25 mm Three times the diameter of the steel bars forming the helix 3) If an increased load on the column on the strength of helical reinforcement is not allowed for , its pitch should not exceed the following distances: The least lateral dimension of the compression member, Sixteen times the smallest diameter of the longitudinal bars to be tied, and 300 mm FLOORS Floors are flat supporting elements of a building. They divide a building into different levels thereby creating more accommodation on a given plot of land. The basic purpose of a floor is to provide a firm and dry platform for people and other items like furniture, stores, equipment’s etc. floor is generally referred to by its location. A floor provided for accommodation below the natural ground level is termed as basement floor. A floor immediately above the ground is termed as ground floor and all other floors such as 1st floor, 2nd floor etc. Doors, Windows and Ventilators A door may be defined as a barrier secured in an opening left in a wall to provide usual means of access to a building, room or passage. This can be termed as the most constantly used moving component in a building. A door normally consists of two components namely (1) Door frame (2) Door shutter. The door frame is permanently held in position and fixed to the masonry of the opening with the help of hold-fasts or raw plugs. Shutter is the moving part of the door. Doors are made out of material like wood, steel, aluminums, plastic, flexible rubber etc. they can be side hung and sliding, folding, revolving or rolling type depending upon the functional requirement. A window may be defined as an opening left in a wall for the purpose of providing day light, vision and ventilation. Similar to door, a window has a frame and one or more shutters. The shutters are normally fitted with glass or similar transparent material. The windows can be side hung, top or bottom hung, louvered types and the shutters can be fully glazed, paneled and glazed or fully paneled types. STAIRS A stair may be defined as a structure comprising of a number of steps connecting one floor to another. The stair must be constructed in such a manner that it is safe and comfortable to use and it should be so located as to permit easy communication. Stairs may be made from material like timber, stone, bricks, steel, reinforced concrete etc. the selection of the type of material to be used depends upon the aesthetical importance, funds available, durability and fire resisting qualities desired. ROOF It is the uppermost component of a building and its main function is to cover the space below and protect it from rain, snow, sun, wind etc. a roof basically consist of two component name. (1)The roof decking and (2) The roof covering. The roof decking is the structural component which supports the roof covering. A roof can be either flat, pitched or curved in shape. The choice of type of roof is made keeping in view the location of the building, weather conditions, funds available and functional and aesthetics requirement. The structural component or roof decking in case of pitched roof is generally a truss, in case of curved roof it is a shell or dome and in case of flat roof it is a flat slab. The roof covering or roofing which is provided over pitched roof could be in the form of tiles, slates, A.C. sheets, G.I. sheets, etc. In case of flat of a layer of varying thickness of material like lime concrete, mud phuska etc. the terracing serves dual purpose (1) of providing suitable slopes on the roof top for draining of rain water and (2) of acting as insulation layer for providing thermal comfort to the users of the space below. BUILDING FINISHES A building is considered incomplete till such time surface of its components is given appropriate treatment. Building finishes include items like plastering, pointing, white/color washing, painting varnishing, distempering etc. the building finishes not only protect the surface from adverse effect of weather but also provide decorative effect. PLANNING AND DESIGN OF BUILDING Principles of planning Before starting the planning for construction of a building we must bear in mind the following points:- 1. Selection of site The site required for the building is to be selected very carefully because it gives beauty to the building. Following points to be considered for selection of proper site:- It should be on fairly level ground. As far as possible it should be at place where filling is minimum possible. It should not be constructed on the soil “made up type” to avoid differential settlement of building. The soil should be adequate bearing capacity of soil to withstand pressure. It is most important that civic amenities like water, drainage sewers, electric supply, and telephone lines are available at site. Ground water table at site should not be high; it creates dampness in the building They should be easy approachable by pacca road. Residential site should be away from industries, workshops, factories etc. Topographical features of the area also play an important role in selection of site. 2. Building bye laws :- Before starting the planning process of a building one must have the prior knowledge of bye laws of the area. These bye laws are made by the state government/municipal corporation/ municipal corporations/municipal committees etc to guide the planner architects to design the proposed building in a systematic manner. These bye laws differ from state to state. These bye laws are generally these are not affective in rural areas. The constructions of buildings are done strictly in accordance with these bye laws. So it is most important to know these bye laws before hand. 3. Orientation of buildings:- The word orientation means to give proper direction to the building so that it gains the gifts of natural resource such as sun, rain, air etc to a great extent as and when required. Properly oriented building gets the reasonable amount of air and light. We know that India is a country where summer season has longest span of about 8 months as such it is hot country with abundant of light. So the building exposed to the sun gets heated in day and remain hot for most of night. It is required that the orientation of building should be done in such away that it is not exposed to direct rays of sun for proper orientation, following should be known Direction of wind: It is also important to know the direction of wind in all seasons. In summer it is required to have maximum access to air in the building while in winter season the cold year to enter the building is required to be avoided. Rainfall of the area: the intensity of rainfall of the area of the site and its direction also affect the orientation. To avoid the direct showers of rain with high velocity to enter the building directly, the provision of verandahs, sunshades etc is required to be made in the building. Site conditions of buildings: it is required that the building should receive minimum radiation of sun in summer and maximum in winter. For this it is very much essential to know the path of the sun along with duration of the sunshine to exposed surface of the building to avoid direct entry of sun rays to the building provision of verandahs to the living room towards east and west is made. The windows are protected by Sunshades, chhajjas etc. The exposure to sun can also reduce by shaded trees on sunny sides of north and east side of building. The bedrooms should be placed in direction of prevailing wind and also prevented by heat by providing verandah. Kitchen to be provided to the eastern corner or n-e corner. W.c’s should be provided in such a way that the wind comes through these should pass away from the building. SEQUENCE OF STRUCTURE WORK • Site clearance • Demarcation of site • Positioning of central coordinate is (0 ,0,0) as per grid plan • Surveying and layout • Excavation • Laying of PCC • Reinforcement • Shuttering and Scaffolding • Concreting • Machinery • Brick work • Plastering Site Clearance- The very first step is site clearance which involves removal of grass and vegetation along with any other objections which might be there in the site location. Demarcation of Site- The whole area on which construction is to be done is marked so as to identify the construction zone. Positioning of Central coordinate and layout- The centre point was marked with the help of a thread and plumb bob as per the grid drawing. With respect to this center point, all the other points of columns were to be decided so its exact position is very critical. Excavation -Excavation was carried out both manually as well as mechanically. Normally 1-2 earth excavators (JCB’s) were used for excavating the soil. Adequate precautions are taken to see that the excavation operations do not damage the adjoining structures. Excavation is carried out providing adequate side slopes and dressing of excavation bottom. Laying of PCC After the process of excavation, laying of plain cement concrete that is PCC is done. A layer of 4 inches was made in such a manner that it was not mixed with the soil. It provides a solid base for the raft foundation and a mix of 1:5:10 that is, 1 part of cement to 5 parts of fine aggregates and 10 parts of coarse aggregates by volume were used in it. Plain concrete is vibrated to achieve full compaction. Concrete placed below ground should be protected from falling earth during and after placing. Concrete placed in ground containing deleterious substances should be kept free from contact with such a ground and with water draining there from during placing and for a period of seven days. When joint in a layer of concrete are unavoidable, and end is sloped at an angle of 30 and junctions of different layers break joint in laying upper layer of concrete. The lower surface is made rough and clean watered before upper layer is laid. LAYING OF FOUNDATION & MATERIALS USED At our site, isolated foundations are used to spread the load from a structure over a large area, normally the entire area of the structure. Normally isolated foundation is used when loads are not much heavy CEMENT Portland cement is composed of calcium silicates and aluminate and alumino ferrite It is obtained by blending predetermined proportions limestone clay and other minerals in small quantities which is pulverized and heated at high temperature – around 1500 degree centigrade to produce ‘clinker’. The clinker is then ground with small quantities of gypsum to produce a fine powder called Ordinary Portland Cement (OPC). When mixed with water, sand and stone, it combines slowly with the water to form a hard mass called concrete. Cement is a hygroscopic material meaning that it absorbs moisture In presence of moisture it undergoes chemical reaction termed as hydration. Therefore cement remains in good condition as long as it does not come in contact with moisture. If cement is more than three months old then it should be tested for its strength before being taken into use. The Bureau of Indian Standards (BIS) has classified OPC in three different grades The classification is mainly based on the compressive strength of cement-sand mortar cubes of face area 50 cm2 composed of 1 part of cement to 3 parts of standard sand by weight with a water-cement ratio arrived at by a specified procedure. The grades are (i) 33 grade (ii) 43 grade (iii) 53 grade The grade number indicates the minimum compressive strength of cement sand mortar in N/mm2 at 28 days, as tested by above mentioned procedure. Portland Pozzolana Cement (PPC) is obtained by either grinding a pozzolanic material with clinker and gypsum, or by blending ground pozzolana with Portland cement. Nowadays good quality fly ash is available from Thermal Power Plants, which are processed and used in manufacturing of PPC. ADVANTAGES OF USING PORTLAND POZZOLANA CEMENT OVER OPC Pozzolana combines with lime and alkali in cement when water is added and forms compounds which contribute to strength, impermeability and sulphate resistance. It also contributes to workability, reduced bleeding and controls destructive expansion from alkali-aggregate reaction. It reduces heat of hydration thereby controlling temperature differentials, which causes thermal strain and resultant cracking n mass concrete structure like dams. The colour of PPC comes from the colour of the pozzolanic material used. PPC containing fly ash as a pozzolana will invariably be slightly different colour than the OPC. One thing should be kept in mind that is the quality of cement depends upon the raw materials used and the quality control measures adopted during its manufacture, and not on the shade of cement. The cement gets its colour from the nature and colour of the raw materials used, which will be different from factory to factory, and may even differ in the different batches of the cement produced in the factory. Further, the colour of the finish concrete is affected also by the colour of aggregates, and to a lesser extent by the colour of the cement. Preference for any cement on the basis of colour alone is technically misplaced. SETTLING OF CEMENT When water is mixed with cement, the paste so formed remains pliable and plastic for a short time. During this period it is possible to disturb the paste and remit it without any deleterious effects. As the reaction between water and cement continues, the paste loses its plasticity. This early period in the hardening of cement is referred to as ‘setting’ of cement. INITIAL AND FINAL SETTING TIME OF CEMENT Initial set is when the cement paste loses its plasticity and stiffens considerably. Final set is the point when the paste hardens and can sustain some minor load. Both are arbitrary points and these are determined by Vicat needle penetration resistance Slow or fast setting normally depends on the nature of cement. It could also be due to extraneous factors not related to the cement. The ambient conditions play an important role. In hot weather, the setting is faster, in cold weather,setting is delayed Some types of salts, chemicals,, etcif inadvertently get mixed with the sand, aggregate and water could accelerate or delay the setting of concrete. STORAGE OF CEMENT It needs extra care or else can lead to loss not only in terms of financial loss but also in terms of loss in the quality. Following are the don’t that should be followed - (i) Do not store bags in a building or a go-down in which the walls, roof and floor are not completely weatherproof. (ii) Do not store bags in a new warehouse until the interior has thoroughly dried out. iii) Do not keep the content with badly fitting windows and doors. Make sure they fit properly and ensure that they are kept shut. (iv) Do not stack bags against the wall. Similarly, don’t pile them on the floor unless it is a dry concrete floor. If not, bags should be stacked on wooden planks or sleepers. (v) Do not forget to pile the bags close together (vi) Do not pile more than 15 bags high and arrange the bags in a header-and-stretcher fashion. (vii) Do not disturb the stored cement until it is to be taken out for use. (viii) Do not take out bags from one tier only. Step back two or three tiers. (ix) Do not keep dead storage. The principle of first-in first-out should be followed in removing bags. (x) Do not stack bags on the ground for temporary storage at work site. Pile them on a raised, dry platform and cover with tarpaulin or polythene sheet. COARSE AGGREGATE Coarse aggregate for the works should be river gravel or crushed stone .It should be hard, strong, dense, durable, clean, and free from clay or loamy admixtures or quarry refuse or vegetable matter. The pieces of aggregates should be cubical, or rounded shaped and should have granular or crystalline or smooth (but not glossy) non-powdery surfaces.Aggregates should be properly screened and if necessary washed clean before use. Coarse aggregates containing flat, elongated or flaky pieces or mica should be rejected. The grading of coarse aggregates should be as per specifications of IS-383. After 24-hrs immersion in water, a previously dried sample of the coarse aggregate should not gain in weight more than 5%. Aggregates should be stored in such a way as to prevent segregation of sizes and avoid contamination with fines. Depending upon the coarse aggregate color, there quality can be determined as: Black => very good quality Blue => good Whitish =>bad quality FINE AGGREGATE Aggregate which is passed through 4.75 IS Sieve is termed as fine aggregate. Fine aggregate is added to concrete to assist workability and to bring uniformity in mixture. Usually, the natural river sand is used as fine aggregate. Important thing to be considered is that fine aggregates should be free from coagulated lumps. Grading of natural sand or crushed stone i.e. fine aggregates shall be such that not more than 5 percent shall exceed 5 mm in size, not more than 10% shall IS sieve No. 150 not less than 45% or more than 85% shall pass IS sieve No. 1.18 mm and not less than 25% or more than 60% shall pass IS sieve No. 600 micron. REINFORCEMENT Steel reinforcements are used, generally, in the form of bars of circular cross section in concrete structure. They are like a skeleton in human body. Plain concrete without steel or any other reinforcement is strong in compression but weak in tension. Steel is one of the best forms of reinforcements, to take care of those stresses and to strengthen concrete to bear all kinds of loads. Mild steel bars conforming to IS: 432 (Part I) and Cold-worked steel high strength deformed bars conforming to IS: 1786 (grade Fe 415 and grade Fe 500, where 415 and 500 indicate yield stresses 415 N/mm2 and 500 N/mm2 respectively) are commonly used. Grade Fe 415 is being used most commonly nowadays. This has limited the use of plain mild steel bars because of higher yield stress and bond strength resulting in saving of steel quantity. Some companies have brought thermo mechanically treated (TMT) and corrosion resistant steel (CRS) bars with added features. Bars range in diameter from 6 to 50 mm. Cold-worked steel high strength deformed bars start from 8 mm diameter. For general house constructions, bars of diameter 6 to 20 mm are used. Transverse reinforcements are very important. They not only take care of structural requirements but also help main reinforcements to remain in desired position. They play a very significant role while abrupt changes or reversal of stresses like earthquake etc. They should be closely spaced as per the drawing and properly tied to the main/longitudinal reinforcement. TERMS USED IN REINFORCEMENT BAR-BENDING-SCHEDULE Bar-bending-schedule is the schedule of reinforcement bars prepared in advance before cutting and bending of rebar’s. This schedule contains all details of size, shape and dimension of rebar’s to be cut. LAP LENGTH Lap length is the length overlap of bars tied to extend the reinforcement length.. Lap length about 50 times the diameter of the bar is considered safe. Laps of neighboring bar lengths should be staggered and should not be provided at one level/line. At one cross section, a maximum of 50% bars should be lapped. In case, required lap length is not available at junction because of space and other constraints, bars can be joined with couplers or welded (with correct choice of method of welding). ANCHORAGE LENGTH This is the additional length of steel of one structure required to be inserted in other at the junction. For example, main bars of beam in column at beam column junction, column bars in footing etc. The length requirement is similar to the lap length mentioned in previous question or as per the design instructions COVER BLOCK Cover blocks are placed to prevent the steel rods from touching the shuttering plates and there by providing a minimum cover and fix the reinforcements as per the design drawings. Sometimes it is commonly seen that the cover gets misplaced during the concreting activity. To prevent this, tying of cover with steel bars using thin steel wires called binding wires (projected from cover surface and placed during making or casting of cover blocks) is recommended. Covers should be made of cement sand mortar (1:3). Ideally, cover should have strength similar to the surrounding concrete, with the least perimeter so that chances of water to penetrate through periphery will be minimized. Provision of minimum covers as per the Indian standards for durability of the whole structure should be ensured. Shape of the cover blocks could be cubical or cylindrical. However, cover indicates thickness of the cover block. Normally, cubical cover blocks are used. As a thumb rule, minimum cover of 2” in footings, 1.5” in columns and 1” for other structures may be ensured. Structural element Cover to reinforcement (mm) Footings 40 Columns 40 Slabs 20 Beams 25 Retaining wall 25 for earth face 20 for other face Reinforcement should be free from loose rust, oil paints, mud etc. it should be cut, bent and fixed properly. The reinforcement shall be placed and maintained in position by providing proper cover blocks, spacers, supporting bars, laps etc. Reinforcements shall be placed and tied such that concrete placement is possible without segregation, and compaction possible by an immersion vibrator. For any steel reinforcement bar, weight per running meter is equal to d*d/162 Kg, where d is diameter of the bar in mm. For example, 10 mm diameter bar will weigh 10×10/162 = 0.617 Kg/m. Three types of bars were used in reinforcement of a slab. These include straight bars, crank bar and an extra bar. The main steel is placed in which the straight steel is binded first, then the crank steel is placed and extra steel is placed in the end. The extra steel comes over the support while crank is encountered at distance of ¼(1-distance between the supports) from the surroundings supports. For providing nominal cover to the steel in beam, cover blocks were used which were made of concrete and were casted with a thin steel wire in the center which projects outward. These keep the reinforcement at a distance from bottom of shuttering. For maintaining the gap between the main steel and the distribution steel, steel chairs are placed between them. SHUTTERING AND SCAFFOLDING The term ‘SHUTTERING’ or ‘FORMWORK’ includes all forms, moulds, sheeting, shuttering planks, walrus, poles, posts, standards, V-Heads, struts, and structure, ties, walling steel rods, bolts, wedges, and all other temporary supports to the concrete during the process of sheeting. Formwork comes in several types: 1. Traditional timber formwork. The formwork is built on site out of timber and plywood or moisture-resistant particleboard. It is easy to produce but time-consuming for larger structures, and the plywood facing has a relatively short lifespan. It is still used extensively where the labour costs are lower than the costs for procuring re-usable formwork. It is also the most flexible type of formwork, so even where other systems are in use, complicated sections may use it. 2. Engineered Formwork Systems. This formwork is built out of prefabricated modules with a metal frame (usually steel or aluminium) and covered on the application (concrete) side with material having the wanted surface structure (steel, aluminium, timber, etc.). The two major advantages of formwork systems, compared to traditional timber formwork, are speed of construction (modular systems pin, clip, or screw together quickly) and lower life-cycle costs (barring major force, the frame is almost indestructible, while the covering if made of wood; may have to be replaced after a few - or a few dozen - uses, but if the covering is made with steel or aluminium the form can achieve up to two thousand uses depending on care and the applications). 3. Re-usable plastic formwork. These interlocking and modular systems are used to build widely variable, but relatively simple, concrete structures. The panels are lightweight and very robust. They are especially suited for low-cost, mass housing schemes. 4. Permanent Insulated Formwork. This formwork is assembled on site, usually out of insulating concrete forms (ICF). The formwork stays in place after the concrete has cured, and may provide advantages in terms of speed, strength, superior thermal and acoustic insulation, space to run utilities within the EPS layer, and integrated furring strip for cladding finishes. 5. Stay-In-Place structural formwork systems. This formwork is assembled on site, usually out of prefabricated fibre-reinforced plastic forms. These are in the shape of hollow tubes, and are usually used for columns and piers. The formwork stays in place after the concrete has cured and acts as axial and shear reinforcement, as well as serving to confine the concrete and prevent against environmental effects, such as corrosion and freeze-thaw cycles. Wooden formwork Shuttering of column ERECTION OF FORMWORK The following applies to all formwork: 1. Care should be taken that all formwork is set to plumb and true to line and level. 2. When reinforcement passes through the framework care should be taken to ensure close fitting joints against the steel bars so as to avoid loss of fines during the compaction of concrete. 3. If formwork is held together by bolts or wires, these should be so fixed that no iron is exposed on surface against which concrete is to be laid. 4. Provision is made in the shuttering for beams, columns and walls for port hole of convenient size so that all extraneous materials that may be collected could be removed just prior to concreting. 5. Formwork is so arranged as to permit removal of forms without jarring the concrete. 6. Wedges, clamps, and bolts should be used where practicable instead of nails. 7. Surface of forms in contact with concrete are oiled with a mould oil of approved quality. The use of oil, which darkens the surface of concrete, is not allowed. Oiling is done before reinforcement is placed and care taken that no oil comes in contact with the reinforcement while it is placed in position. The framework is kept thoroughly wet during concreting. Immediately before concreting is commenced, the formwork is carefully examined to ensure the following: 1. Removal of all dirt, shavings, sawdust and other refuse by brushing and washing. 2. The tightness of joint between panels of sheathing and between these and any hardened core. 3. The correct location of tie bars bracing and spacing, and especially connections of bracing. 4. That all wedges are secured and firm in position. 5. That provision is made for traffic on formwork not to bear directly on reinforcement steel. VERTICALITY OF THE STRUCTURE All the outer columns of the frame were checked for plumb-bob as the work proceeds to upper floors. Internal columns were checked by taking measurements from outer row of columns for their exact position. STRIPPING TIME OR REMOVAL OF FORMWORK Form were not struck until the concrete has attained a strength at least twice the stress to which the concrete may be subjected at time of removal of form work. The strength referred is that of concrete using the same cement and aggregates with the same proportions and cured under conditions of temperature and moisture similar to those exiting on the work. Where so required, form work was left longer in normal circumstances. Form work was removed in such a manner as would not cause any shock or vibration that would damage the concrete. Before removal of props, concrete surface was exposed to ascertain that the concrete has sufficiently hardened. Where the shape of element is such that the concrete has sufficiently hardened. Where the shape of element is such that form work has re-entrant angles, the form work was removed as soon as possible after the concrete has set, to avoid shrinkage cracking occurring due to the restraint imposed. Following times limits should be followed: Structural Component Age Footings 1 day Sides of beams, columns, lintels, wall 2 days Underside of beams spanning less than 6m 14 days Undesirable of beams spanning over 6m 21 days Underside of slabs spanning less than 4m 7 days Underside of slabs spanning more than 4m 14 days Flat slab bottom 21 days SCAFFOLDING When the height of the wall or column or other structural member of building exceeds about 1.5m. Temporary structures are needed to support the platform over which the workmen can sit and carry on the constructions. These temporary structures, constructed very close to wall, is in the form of timber or steel formwork, commonly called as scaffolding. At our site the material used for scaffolding are standards, ledgers. These are made of bamboo of different lengths according to the requirements of site. COMPONENT PARTS OF SCAFFOLDING 1. STANDARDS :- These are the vertical members of formwork, supported on the ground or drums, or embedded into the ground. 2. LEDGERS :- These are horizontal members, running parallel to the wall. As shown in above picture. 3. BRACES :- These are diagonal members fixed on standards, which use to tie up the standards in correct manner and also it helps to keep the standards in its proper position. 4. COUPLERS :- Couplers are very important component used in scaffolding which is used to tie up standards and horizontal main cross pipes. These contain a pair of nut and bolts by which we tighten the standards and cross pipes as shown in picture. 5. BASE PLATES :- Base plates are used below standards which avoid sharpen edge of standards to sink or penetrate in the ground. It also increases the bearing area below standards. These plates are normally of mild steel. 6. BOARDING :-These are horizontal members which support workmen and material. These are supported on the horizontal cross pipes or ledgers. At our site these are of rectangular steel pipes which are welded with the help of a perpendicular rectangular pipe of same size. Formwork CONCRETING Concrete is a mixture of cement, sand, stone aggregates and water. A cage of steel rods used together with the concrete mix leads to the formation of Reinforced Cement Concrete popularly known as RCC. Concrete has two main stages 1) Fresh Concrete 2) Hardened concrete Fresh Concrete should be stable and should not segregate or bleed during transportation and placing when it is subjected to forces during handling operations of limited nature. The mix should be cohesive and mobile enough to be placed in the form around the reinforcement and should be able to cast into the required shape without losing continuity or homogeneity under the available techniques of placing the concrete at a particular job. The mix should be amenable to proper and through compaction into a dense, compact concrete with minimum voids under the existing facilities of compaction at the site. A best mix from the point of view of compatibility should achieve a 99 percent elimination of the original voids present. HARDENED CONCRETE One of the most important properties of the hardened concrete is its strength which represents the ability if concrete to resist forces. If the nature of the force is to produce compression, the strength is termed compressive strength. The compressive strength of hardened concrete is generally considered 10 be the most important property and is often taken as the index of the overall quality of concrete. The strength can indirectly give an idea of the most of the other properties of concrete which are related directly to the structure of hardened cement paste. A stronger concrete is dense, compact, impermeable and resistant to weathering and to some chemicals. However, a stronger concrete may exhibit higher drying shrinkage with consequent cracking, due to the presence of higher cement content. Some of the other desirable properties like shear and tensile strengths, modulus of elasticity, bond, impact and durability etc. are generally related to compressive strength. As the compressive strength can be measured easily on standard sized cube or cylindrical specimens, it can be specified as a criterion for studying the effect of any variable on the quality of concrete. However, the concrete gives different values of any property under different testing conditions. Hence method of testing, size of specimen and the rate of loading etc. are stipulated while testing the concrete to minimize the variations in test results. The statistical methods are commonly used for specifying the quantitative value of any particular property of hardened concrete. COMPRESSIVE STRENGTH :-The compressive strength of concrete is defined as the load which causes the failure of specimen, per unit area of cross-section in uniaxial compression under given rate of loading. The strength of concrete is expressed as N/mm2. The compressive strength at 28 days after casting is taken as a criterion for specifying the quality of concrete. This is termed as grade of concrete. IS 456:2000 stipulates the use of 150 mm cubes. TENSILE STRENGTH:-The concrete has low tensile strength: it ranges from 8-12 per cent of its compressive strength. An average value of 10 per cent is generally adopted. SHEAR STRENGTH :-The concrete subjected to bending and shear stress is accompanied by tensile and compressive stresses. The shear failures are due to resulting diagonal tension. The shear strength is generally 12-13 per cent of its compressive strength. BOND STRENGTH :-The resistance of concrete to the slipping of reinforcing bars embedded in concrete is called bond strength. The bond strength is provided by adhesion of hardened cement paste, and by the friction of concrete and steel. It is also affected by shrinkage of concrete relative to steel. On an average bond strength is taken as 10 per cent of its compressive strength. COMPACTION OF CONCRETE Compaction is done by the use of vibrators. Compaction of concrete by vibration is considered essential for all important works especially in situations where reinforcements are congested or the member is required is to have exposed to concrete surface finish. When vibrators are used leaner but stiff, concrete mix should be used to obtain greater durability and highest strength, mixes which are to stiff to consolidate by hand compaction can be easily compacted by mechanical compaction, in case the concrete is compacted by vibrations, during which the vibrator communicates rapid vibrations to the particles, increases the fluidity of concrete. Due to vibrations the particles occupy a more stable position and concrete fills all the space and present is force out to the surface, resulting in dense and durable concrete. TYPES OF VIBRATORS Following are the type of vibrates usually used to compact concrete: 1. Internal vibrators 2. External vibrators 3. Surface vibrators 4. Vibrating table Internal vibrator consists of metal road like vibrating head which is immersed in the full depth of concrete layer. It is also known as poker or needle vibrator and is consider to be most effective type of vibrator as it comes into intimate contact with concrete. External vibrators are placed against the concrete form-work and vibrating force for compaction is conveyed to the concrete through the form work. These vibrators are also called form vibrators. The vibrator is rigidly clamped to form work resting on a elastic spot, so that both the form and concrete are vibrated. Considerable proportion of work done is consumed in vibrating resulting in low efficiency of the system. Surface vibrators are mounted on platform and are generally used to compact and finish bridge, road slab etc. These are also external vibrators and are suitable for precast concrete work. It provides a reliable means of compaction of pre-cast concrete and has the advantage of offering uniform vibration. Vibrating table is used for consolidation of pre-cast units. Surface vibrators is used there a wide horizontal surface occurs such as dams and very thick walls large type of surface vibrators is there but pen type vibrator are used most. When concrete is placed on such tables, mechanical compaction takes place which has many advantages. Each vibrator have its own advantages and disadvantages, hence the choice between different types should be made correctly. Concrete to be compacted by vibration, should be designed properly. The consistency of concrete depends of conditions of placing, type of mix, and the efficiency of vibrator. The slum of such concrete should not be more than 5 cm in any case; otherwise segregation of concrete will take place, which should never be allowed to occur. MACHINERY 1. MECHANICAL COMPACTOR: It is used for the compaction of concrete at site. This machine is handled manually. 2. TRUCK MIXER: Truck Mixer is used for providing R.M.C (Ready Mix Concrete) at far away sites. Truck Mixer consists of a large hollow tilted circular drum fitted with a water tank. Different constituents of concrete are mixed in the truck mixer drum at batching plant & transported to required site .The drum keeps on revolving during the journey which does not allow concrete to get stabilized. One Truck Mixer contains 7 cubic meter of concrete. 3. JCB DIGGER: It is used for excavation, filling & transportation of materials at the site. This machine has various models like: 3DX, 4Dx etc. 4. TILTED DRUM MIXER: This machine has got its name from its tilted drum, which is tilted at some angle. It is used for preparing fresh concrete at site itself by mixing cement, sand, aggregates & water in proper amount. BRICK WORK Brickwork is masonry done with bricks and mortar and is generally used to build partition walls. In the site, all the external walls were of concrete and most of the internal walls were made of bricks. English bond was used and a ratio of 1:4 (1 part of cement: 4 parts of sand) and 1:6 were also used depending upon whether the wall is 4.5” or 9”. The reinforcement shall be 2 nos. Mild steel round bars or as indicated. The diameter of bars was 8mm. The first layer of reinforcement was used at second and then at every fourth course of brick work. The bars were properly anchored at their ends where the portions and or where these walls join with other walls. The in laid steel reinforcement was completely embedded in mortar. Bricks can be of two types. These are Traditional Bricks: :- The dimension if traditional bricks vary from 21cm to 25cm in length, 10 to 13 cm in width and 7.5cm in height in different parts of country. The commonly adopted normal size of traditional bricks is 23*11.5*7.5 cm with a view to achieve uniformity in size of bricks all over country. Modular Bricks: :- Indian standard institution has established a standard size of bricks such a brick is known as a modular brick. The normal size of brick is taken as 20*10*10 cm whereas its actual dimensions are 19*9*9 cm masonry with modular bricks workout to be cheaper there is saving in the consumption of bricks, mortar and labor as compared with masonry with traditional bricks. STRENGTH OF BRICK MASONARY The permissible compressive stress in brick masonry depends upon the following factors: 1. Type and strength of brick. 2. Mix of motor. 3. Size and shape of masonry construction. The strength of brick masonry depends upon the strength of bricks used in the masonry construction.