Learn about civil engineering

Levelling (or Leveling) is a branch of surveying, the object of which is:  i) to find the elevations of given points with respect to a given or assumed datum, and ii) to establish points at a given or assumed datum. The first operation is required to enable the works to be designed while the second operation is required in the setting out of all kinds of engineering works. Levelling deals with measurements in a vertical plane. Level surface: A level surface is defined as a curved surface which at each point is perpendicular to the direction of gravity at the point. The surface of a still water is a truly level surface. Any surface parallel to the mean spheroidal surface of the earth is, therefore, a level surface. Level line: A level line is a line lying in a level surface. It is, therefore, normal to the plumb line at all points. Horizontal plane: Horizontal plane through a point is a plane tangential to the level surface at that point. It is, therefore, perpendicular to the p

DEFINE :  Surveying has to do with the determination of the relative spatial location of points on or near  the surface of the earth. • It is the art of measuring horizontal and vertical distances between objects, of measuring angles between lines, of determining the direction of lines, and of establishing points by predetermined angular and linear measurements. • Along with the actual survey measurements are the mathematical calculations. • Distances, angles, directions, locations, elevations, areas, and volumes are thus determined from the data of the survey. • Survey data is portrayed graphically by the construction of maps, profiles, cross sections, and diagrams. Types of surveying: Geodetic Surveying: The type of surveying that takes into account the true shape of the earth. These surveys are of high precision and extend over large areas. Plane Surveying:  The type of surveying in which the mean surface of the earth is considered as a plane, or in which its sp

Tests on Cement at Construction Site To Check Quality of Cement Quality tests on cements at construction site (also called field tests on cement) are carried to know the quality of cement supplied at site. It gives some idea about cement quality based on colour, touch and feel and other tests. Tests on Cement at Construction site The following are the quality tests on cement at construction site: Color test Presence of lumps Adulteration test Temperature test Float tests Strength test Setting test Date of packing Color Test of Cement The color of the cement should be uniform. It should be grey colour with a light greenish shade. Presence of Lumps The cement should be free from any hard lumps. Such lumps are formed by the absorption of moisture from the atmosphere. Any bag of cement containing such lumps should be rejected. <script type="text/javascript" language="javascript"> var aax_size='300x600'; var aax_pub

A cement is a binder, a substance used in construction that sets, hardens and adheres to other materials, binding them together. Cement is seldom used solely, but is used to bind sand and gravel (aggregate) together. Cement is used with fine aggregate to produce mortar for masonry, or with sand and gravel aggregates to produce concrete The following are the types of cement that are in practice: Rapid Hardening Cement Quick setting cement Low Heat Cement Sulphates resisting cement Blast Furnace Slag Cement High Alumina Cement White Cement Coloured cement Pozzolanic Cement Air Entraining Cement Hydrographic cement Types of Cement and uses Rapid Hardening Cement Composition :  Increased Lime content   Purpose :  Attains high strength in early days it is used in concrete where formworks are removed at an early stage. Quick setting cement   Composition:  Small percentage of aluminum sulphate as an accelerator and reducing percentage of Gypsum with fine grin

CONCRETE GRADES: M5 = 1:4:8 M10= 1:3:6 M15= 1:2:4 M20=  1:1.5:3 M25= 1:1:2 CLEAR COVER TO MAIN REINFORCEMENT: 1.FOOTINGS : 50 mm 2.RAFT  FOUNDATION.TOP : 50 mm 3.RAFT FOUNDATION.BOTTOM/SIDES : 75 mm 4.STRAP BEAM  : 50 mm 5.GRADE SLAB : 20 mm 6.COLUMN : 40 mm 7.SHEAR WALL : 25  mm 8.BEAMS : 25 mm 9.SLABS : 15 mm 10.FLAT SLAB : 20 mm 11.STAIRCASE  : 15 mm 12.RET. WALL : 20/ 25 mm on earth 13.WATER RETAINING STRUCTURES :  20/30 mm WEIGHT OF ROD PER METER LENGTH: DIA WEIGHT PER METER = D*D/162 6mm = 0.222Kg 8mm = 0.395 Kg 10mm = 0.616 Kg 12mm = 0.888  Kg 16mm = 1.578 Kg 20mm = 2.466 Kg 25mm = 3.853 Kg 32mm = 6.313  Kg 40mm = 9.865 Kg

About Safe bearing capacity Excavate a pit of required depth. (preferably equal to the depth of foundation) Take a solid ball or square cube of known weight and dimension. Drop the ball or square cube several times, from a known height on to the bottom surface of excavated pit. Calculate the average depth of impression made several times on the bottom surface of the excavated pit. Let “d” is the average depth of impression. CALCULATION Calculate the ultimate resistance of soil ( R ) using the formula given below. R = (w * h) / d Where, R = Ultimate resistance of soil (in kg) d = Average depth of impression (in cm) w = Weight of the solid ball or square cube (in kg) h = Height of fall of solid ball or cube (in cm) If “A” is the cross-sectional area of the solid steel ball or cube, then resistance of soil per unit area is calculated using following formula. Resistance of soil per unit area (in kg/cm2) = R / A Safe bearing capacity (in kg/cm2) = R / (A * F.O.S

Follow this for more: 1.Common misconception is that all civil engineers will be site engineers which is wrong. There will be civil engineers in the following functions too. Planning Contracts   Quantity survey Tendering and bidding Design Quality Control, 2. When it comes to site execution, Every civil engineer must know that the supervisors working under them are not their slaves. We earn respect only when we show some respect to our juniors level engineers or supervisors. When safety department in-charge says something, civil engineers need to follow to avoid any unwanted circumstances (like accidents or death in the site). Don't waste the scrap. Recycle it and reuse it. Ex: You can even use unwanted cut steel bars for barricading purpose. 3. When it comes to project execution, Every civil engineer's ultimate aim should be completing the project within the stipulated time without any delay and within the specified budget Minimum thickness o

LOADS Structural loads or actions are forces, deformations, or accelerations applied to a structure or its components. Loads cause stresses, deformations, and displacements in structures. ... Engineers often evaluate structural loads based upon published regulations, contracts, or specifications. LOAD TYPES The determination of the loads acting on a structure is a complex problem. The nature of the loads varies essentially with the architectural design, the materials, and the location of the structure. Loading conditions on the same structure may change from time to time, or may change rapidly with time. Loads are usually classified into two broad groups: dead loads and live loads. Dead loads (DL) are essentially constant during the life of the structure and normally consist of the weight of the structural elements. On the other hand, live loads (LL) usually vary greatly. The weight of occupants, snow and vehicles, and the forces induced by wind or earthquakes are example

About : A vertical member whose effective length is greater than 3 times Its least lateral dimension carrying compressive loads is called as a column. Columns transfer the loads from the beams or slabs to the footings or foundations. The inclined member carrying compressive loads as In the case of frames and trusses is called as struts. The pedestal is a vertical compression member whose effective length Is less than 3 times Its least lateral dimension. (different types columns) WHY WE PROVIDE COLUMNS? Primarily, Columns carry  Axial Loads and therefore are designed for compression. Other loads from snow, wind or other horizontal forces can cause bending in the columns. Columns then need to be designed for Axial Load and Bending. COLUMNS ARE CLASSIFIED INTO FOUR TYPES:- Based on Shape Based on a type of reinforcement Based on type of loading Based on slenderness ratio Note: It’s just a classification a column can be a combination of both types like a column can be Rect

POST TENSION SLAB: The slab which is tensioned after constructing slab is called Post tension slab. Reinforcement is provided to resist the compression. In Post tension slab the reinforcement is replaced with cables/ steel tendons. Post-tensioning provides a means to overcome the natural weakness of concrete in tension and to make better use of its strength in compression. The principle is easily observed when holding together several books by pressing them laterally. Linder such pressure the whole row gains enough stiffness and strength to ensure its integrity. In concrete structures, this is achieved by placing high-tensile steel tendons/cables in the element before  casting When the concrete reaches the desired strength  the tendons are pulled by special hydraulic jacks and held  in tension using specially designed anchorages fixed at each end of the tendon  This provides compression at the edge of the structural member that increases the strength of the concrete for resisting

Dome Slab:- These kind of slab is generally constructed in temples, Mosques, palaces etc. And Dome slab is built on conventional slab. Thickness of Dome slab is 0.15m. Domes are in semi circle and shuttering is done on conventional slab in dome shape and concrete is filled in shuttering forming dome shapes. This is a one of the types of concrete slabs. PITCH ROOF SLAB: Pitch roof is an inclined slab , generally constructed on resorts for a natural look. Compared to traditional roofing materials Tile-sheets used in pitch roof slab  are extreamely lightweight. This weight saving reduces the timber or steel structural requirements resulting in significant cost savings.Tile-sheets are tailor made for each project offering labour cost savings and reduced site wastage. And the thickness of slab is depends on the tiles we using it may be 2″-8″. This is a one of the types of concrete slabs. Advantages : 1. It sheds off rain water better. 2. It gives you internal storage or ro

  WAFFLE SLAB :- Waffle slab is a reinforced concrete roof or floor containing square grids with deep sides. This kind of slab is majorly used at entrance of hotels, Malls, Restaurants for good pictorial view and to install artificial lighting. This a  type of slab where we find hollow hole in the slab when the formwork is removed.  Firstly PVC trays (pods) are placed on shuttering then reinforcement is provided between the pods and steel mesh is provided at top of the pods and then concrete is filled. After concrete sets the formwork is removed and PVC pods are not removed. This forms hollow hole in it in which hole is closed at one end. The concrete waffle slab is often used for industrial and commercial buildings while wood and metal waffle slabs are used in many other construction sites. This is a one of the types of concrete slabs. Where to use? A waffle slab is a type of slab with holes underneath, giving an appearance of waffles. It is usually used where large spans are r

  HARDY SLAB :- These kind of slabs are generally seen in Dubai and China. This  slab is constructed by hardy Bricks. Hardy bricks are hollow bricks and made up of concrete Hollow blocks are used to fill portions of the slab thickness it saves the  amount of concrete and hence the own weight of the slab is reduced. This kind of slab has a more thickness when compared with the conventional one. The thickness of hardy slab is 0.27m. The method of installing Hardy slab is different from normal  and it is clearly explained below: This is a one of the types of concrete slabs. The dimensions of Hardy brick is 40cm x 20cm x 20cm The process of execution is as follows: Step 1   : Formwork is arranged and then shutters are fixed on the formwork. Step 2  : Hardy blocks are placed on the shutter with one brick gap on the entire shutter. Step 3  : The gaps between the bricks are called as rib. Reinforcement is provided in a form of beam within the gap. Step 4  : After placing the

  HOLLOW CORE RIBBED SLAB:- Hollowcore ribbed slabs derive their name from the voids or cores which run through the units. The cores can function as service ducts and significantly reduce the self-weight of the slabs, maximising structural efficiency. The cores also have a benefit in sustainability terms in reducing the volume of material used. Units are generally available in standard 1200 mm widths and in depths from 110mm to 400 mm. There is total freedom in length of units. This kind of slab is used where the construction has to be done fast. These kind of slabs are Pre cast slabs which are readymade.  The hollowcore ribbed slabs have between four and six longitudinal cores running through them, the primary purpose of the cores being to decrease the weight, and material within the floor, yet maintain maximal strength. To further increase the strength, the slabs are reinforced with 12mm diameter steel strand, running longitudinally. This is a one of the types of concrete slabs.

CONVENTIONAL SLAB:- The slab which is supported with Beams and columns is called conventional slab. In this kind of slab the thickness of slab is small whereas depth of beam is large and load is transferred to beams and from beams to columns. It requires more formwork when compared with the flat slab. and there is no need of providing column caps in conventional slab.  The thickness of conventional slab is 4″ or 10cm. 5″ to 6″ inches is recommended if the concrete will receive occasional heavy loads, such as motor homes or garbage trucks. Normally it is square in shape and has a length of 4m. Reinforcement is provided in conventional slab and the bars which are set in horizontal are called Main Reinforcement Bars and bars which are set in vertical are called Distribution bars. hese types of slabs are used in constructing floors of multi storeyed building. Based on length and breadth of Conventional Slab is classified into two types: One-Way Slab Two-Way Slab 1. ONE WAY SLAB :

1.FLAT SLAB :- Flat slab is a reinforced concrete slab supported directly by concrete columns or caps. Flat slab dont have beams. They are supported on columns itself. Loads are directly transferred to columns. In this type of construction a plain ceiling is obtained thus giving attractive appearance from architectural point of view. The plain ceiling diffuses the light better and is considered less vulnerable in the case of fire than the usual beam slab construction.The flat slab is easier to construct and requires less formwork. The thickness of Flat slab is minimum 8″ or 0.2m. This is a one of the types of concrete slabs. It can be used where : To provide plain ceiling surface giving better diffusion of light Easy constructability with economy in the formwork Larger head room or shorter storey height & pleasing appearance. This kind of slabs are provided in parking Flat slabs are generally used in parking decks, commercial buildings, hotels or places where beam proj

Types of concrete slabs in construction:- There are 16 different types of Slabs in Construction. Some of them are outdated and some of them are frequently used everywhere. In this article i ll give a detailed explanation about an each slab where to use particular slab. Below are the types of concrete slabs. Since this is a lengthy article, we have created a table of contents below for easy navigation. 1 1.Flat Slab:- 1.1 There are four different  types of concrete slabs (FLAT SLABS) 2 2. Conventional Slab 2.1 1. ONE WAY SLAB 2.2 2. TWO WAY SLAB 3 3. Hollow core ribbed Slab 4 4. Hardy Slab 5 5. Waffle Slab 6 7. Pitch roof slab 7 8. Slab with Arches 8 9. Post tension slab 9 10. Pre Tension Slab 10 11. Cable suspension slab 11 12. Low roof slab 12 13. Projected slab 13 15. Sunken Slab 14 15. Miscellaneous Slab 14.0.0.1 Room Chajja or Loft 14.0.0.2 Kitchen Slab 14.0.0.3       3. Lintels 14.0.0.4      4. Sun Shade slab

ROLE OF CONSTRUCTION SITE ENGINEER  Role of Construction Site Engineer depends on the type of work involved and experience of site engineer in a construction project. The duties and responsibilities of a construction site engineer are typically as follows, many of these will be delegated to other engineers on the site according to their experience and ability Setting out the works in accordance with the drawings and specification Liaising with the project planning engineer regarding construction programmes Checking materials and work in progress for compliance with the specified requirements Observance of safety requirements Resolving technical issues with employer’s representatives, suppliers, subcontractors and statutory authorities Quality control in accordance with CSIs/procedures method statements, quality plans and inspection and test plans, all prepared by the project management team and by subcontractors Liaising with company or project purchasing department to

  Bar Bending Schedule (BBS) Bar Bending Schedule, commonly referred to as “BBS” is a comprehensive list that describes the location, mark, type, size, length and number, and bending details of each bar or fabric in a Reinforcement Drawing of a Structure. This process of listing the location, type and size, number of and all other details is called “Scheduling”. In context of Reinforcement bars, it is called bar scheduling. In short, Bar Bending Schedule is a way of organizing rebars for each structural unit, giving detailed reinforcement requirements. General guidelines to be followed in preparing BBS: The bars should be grouped together for each structural unit, e.g. beam, column, etc. In a building structure, the bars should be listed floor by floor For cutting and bending purposes schedules should be provided as separate A4 sheets and not as part of the detailed reinforcement drawings. The form of bar and fabric schedule and the shapes of bar used should be in accor

CONCRETE MIX DESIGN EXAMPLE – M50 GRADE CONCRETE Grade Designation = M-50 Type of cement = O.P.C-43 grade Brand of cement = Standard best quality cement Admixture = Sika [Sikament 170 ( H ) ] Fine Aggregate = Zone-II Sp. Gravity Cement = 3.15 Fine Aggregate = 2.61 Coarse Aggregate (20mm) = 2.65 Coarse Aggregate (10mm) = 2.66 Minimum Cement (As per contract) =400 kg / m3 Maximum water cement ratio (As per contract) = 0.45 Concrete Mix Design Calculation: – 1. Target Mean Strength = 50 + ( 5 X 1.65 ) = 58.25 Mpa 2. Selection of water cement ratio: Assume water cement ratio = 0.35 3. Calculation of water content: Approximate water content for 20mm max. Size of aggregate = 180 kg /m3 (As per Table No. 5 , IS : 10262 ). As plasticizer is proposed we can reduce water content by 20%. Now water content = 180 X 0.8 = 144 kg /m3 4. Calculation of cement content: Water cement ratio = 0.35 Water content per m3 of concrete = 144 kg Cement content = 144/0.35 = 411.4 k

Mix design can be defined as the process of selecting suitable ingredients of concrete and determining their relative proportions with the object of producing concrete of certain minimum strength and durability as economically as possible CONCRETE MIX DESIGN PROCEDURE & EXAMPLE IS456    Concrete mix design is the process of finding the proportions of concrete mix in terms of ratios of cement, sand and coarse aggregates. For e.g., a concrete mix of proportions 1:2:4 means that cement, fine and coarse aggregate are in the ratio 1:2:4 or the mix contains one part of cement, two parts of fine aggregate and four parts of coarse aggregate. The concrete mix design proportions are either by volume or by mass. The water-cement ratio is usually expressed in mass Requirements for concrete mix design:  The grade designation giving the characteristic strength requirement of concrete. The type of cement influences the rate of development of compressive strength of concrete. Maximum

Concrete Slump Test for Workability -Procedure and Results. Concrete slump test is to determine the workability or consistency of concrete mix prepared at the laboratory or the construction site during the progress of the work. Procedure for Concrete Slump Test: Clean the internal surface of the mould and apply oil. Place the mould on a smooth horizontal non- porous base plate. Fill the mould with the prepared concrete mix in 4 approximately equal layers. Tamp each layer with 25 strokes of the rounded end of the tamping rod in a uniform manner over the cross section of the mould. For the subsequent layers, the tamping should penetrate into the underlying layer. Remove the excess concrete and level the surface with a trowel. Clean away the mortar or water leaked out between the mould and the base plate. Raise the mould from the concrete immediately and slowly in vertical direction. Measure the slump as the difference between the height of the mould and that of height poin