DIFFERENCE BETWEEN WORKING STRESS METHOD AND LIMIT STATE METHOD

 The cardinal difference between Working Stress Method (WSM) and Limit State Method (LSM) is : WSM is  an elastic design method whereas LSM is a plastic design method.

In elastic design, i.e WSM, the design strength is calculated such that the stress in material is retained to it's yield limit, under which the material follows Hooke's law, and hence the term "elastic" is used. This method yields to uneconomical design of simple beam, or other structural elements where the design governing criteria is stress (static).

However, in case of shift of governing criteria to other factors such as fatigue stress, both the methods will give similar design. Also, WSM substantially reduces the calculation efforts.

Now coming to the plastic design, i.e. LSM, as the name suggests, the stress in material is allowed to go beyond the yield limit and enter into the plastic zone to reach ultimate strength. Hence the "moment rotation" capacity of beam, for example, is utilized making the design more economical. However, due to the utilization of the non-linear zone, this method involves arduous calculation.

All other differences are mostly derived from the above stated fundamental difference along with few general differences. Some of these  differences are stated below:

1. Serviceability check in case of LSM is required because after the elastic region strain is higher, which results in more deformation, hence a check is necessary.
2. LSM is strain based method whereas WSM is stress based method.
3. LSM is non-deterministic method where WSM is deterministic approach.
4. The partial safety factor is used in LSM whereas Safety factor is used in WSM.
5. Characteristic values (derived from probabilistic approach) are used in case of LSM whereas Average or static values are used in WSM.

HOW TO CLACULATE SHUTTERING AREA FOR CONSTRUCTION

CALCULATION OF SHUTTERING AREA:

Shuttering or formwork is a temporary, rigid structure in which the cast in situ concrete is poured for casting the members to required shape. Different formworks are used for different shape members.

In this article,we will discuss how to calculate the shuttering area before construction.

Before calculating the shuttering area first, we need to know how to calculate the peripheral length of any shape.

PERIPHERAL LENGTH/PERIMETER:

We know that perimeter is the distance around a 2D(two dimensional) shape.

For example, square has four sides. Let's be the length of one side,then

∴The peripheral length = S+S+S+S = 4S.

Rectangle has four sides also but the length ans breadth is different, let length is 'l' and breadth is 'b'

∴Peripheral length = l+b+l+b = 2l+2b

Now coming to the calculation of shuttering area.

Shuttering area = Peripheral length x Depth

Let me show you an example,

 Here the shape is rectangle,

∴Peripheral length = 2l + 2b
                               = (2x1) + (2x0.8)
                               = 2 + 1.6 
                               = 3.6

∴Total shuttering area = Peripheral length x Depth
                                     = 3.6 x 4
                                     = 14.4 sq.m 

HOW TO CALCULATE STEEL QUANTITY FOR RCC BEAM, COLUMN AND SLAB

Following are the steps to calculate the quantity of steel for RCC slab:

• Prepare a bar bending schedule in order to classify different shapes of bars (bent up bar, straight anchor bar, curtail bar etc) and diameters.
• List down all the shapes of bars from the drawing.
• Count the number of bars of each of those shapes.
• Then calculate the cutting length of each of those bars.                                                          

Cutting length of bar = (length of member - deduction for cover on both sides) + development length.

• Then calculate the unit weight of each dia bars by the following formula:

W = d² / 162.
where, 
d is the dia in mm 
w is the weight in kg.

• Then calculate the weight of rebar

Weight of rebar = no. of bars x cutting length x unit weight

• Add all the weight to get the total steel quantity.

NOTE: 
   
    1. Minimum % of steel as per Indian standards are:

• Beam (Tension reinforcement): 

As = 0.85 bd/fy of gross section area.

• Slab - 0.12% of total area
• Column - 0.8% of total area.

    2. Maximum % steel as per Indian standard are:

• Beam - 4% of cross-section area
• Slab - 4% of cross-section area
• Column - 6% of cross-section area.

     3. Development length is usually specified in the drawings, but if not then you can calculate it as,
D.L = Depth - 2 times cover.
     
      4. Binding wire = 10 grams per kg of reinforcement.

      5. No. of stirrups = (length of member - 2 x cover)/spacing + 1.

ADVANTAGES OF RCC STAIRS

RCC STAIRS OR REINFORCED CONCRETE STAIRS:

RCC stairs may be the most common stairs widely used than any other type of stairs. These stairs can be easily moulded to any desired shape and are better tear and fire resistant. The steps of RCC stairs are made by using ordinary cement concrete. Besides ordinary cement concrete, some other superior finishing materials are also used such as marble, terrazzo, tiles etc. to give them better appearances.

ADVANTAGES OF RCC STAIRS:

The advantage of R.C.C stairs are as following:

1. R.C.C stairs are better fire resistant than any other stairs.
2. They are adequately strong and more durable.
3. The steps are no-slippery.
4. They offer better and pleasant appearances.
5. The stairs can be designed for greater widths and longer spans.
6. They can be easily cleaned.
7. R.C.C stairs can be precast or cast in situ.
8. The maintenance cost is almost nil.
9. In modern sky scraper construction always framed structures are adopted, for such structures R.C.C stairs are the one and only stairs which can be used.

METHODS OF ESTIMATION OF BUILDING WORK

The estimation of the quantities of various items of a building such as earth work in excavation, concrete in foundation, brick work in foundation and  plinth,brick work in super structure, etc., may be made by the following methods:

• Center line method
• Long and short wall method

1.Center line method:

In this method, the center line length of walls in a building is multiplied by the breadth and depth of the respective item to get the total quantity of the item. In case of partition or verandah walls joining with the main walls, the center line is reduced by half of the breadth of the layer of the main wall at the same level.

Suitability: This method is especially suited for estimating the circular, hexagonal, octagonal, etc. shaped buildings.

2.Long and short wall method:

In this method, the longer walls are generally treated as long walls and the shorter or partition walls. The long walls are measured out-to-out i.e. center to center length minus half projection one side and half projection on the other side.

Suitability: This method is mostly used irrespective of variable sections of walls.

CIVIL ENGINEERING MEASUREMENTS & CONVERSION FACTORS

Measurement is one of the important things in civil engineering and without measurements, we can not complete any construction. Here I have listed some basic measurements and conversion factors which are most commonly used in civil engineering. Hope it will help you in your work.

BASIC QUANTITIES AND UNITS:

 BASIC STANDARDS:

1 inch = 25.4 mm = 2.54 cm.
1 meter = 39.37 inches = 1.09 yards.
1 liter = 0.22 galls (imp.)
1 gallon (imp.) = 4.546liters. 
1 gallon (US) = 3.785 liters.
1 kilogram (kg) = 2.2046 pounds(lb).
--------------------------------------------------------------
METRIC UNIT OF WEIGHT / MASS :

1 tonne = 1000 kilograms = 10,00,000 grams.
1 quintal = 100 kilograms = 1,00,000 grams.
1 slug = 14.606 kg.
1 slug = 32.2 lb
---------------------------------------------------------------
MEASUREMENTS OF LENGTH:

1 foot = 12 inches.
1 yard = 3 feet.
1 furlong = 220 yards.
1 mile = 8 furlongs.
1 kilometer = 1000 meters.
1 cm = 10 mm.
-----------------------------------------------------------------
METRIC UNITS FOR LIQUID MEASUREMENTS:

1 liter = 100 ml.
1 liter = 1 kg.
1 kiloliter (1000 liters) = 1 cubic meter / 1 cu.m / 1 m³.
-----------------------------------------------------------------
CONVERSION FACTORS:

1 cu.ft = 28.317 liters.
1 cu.ft = 0.028 cu.m
1 cu.ft = 6.24 galls(imp.)
1 cu.ft = 7.48 galls(US)
1 imp.gall = 1.20 galls(US), liquid.
1 imp.gall = 1.03 galls(US), dry.
-----------------------------------------------------------------
MEASUREMENTS OF AREA:

1 acre = 43560 sq.ft.
1 acre = 4046.46 sq.m.
1 acre = 8 kanals.
1 kanal = 20 marlas.
1 marla = 225 sq.ft [*in some regions 272 sq.ft]
1 marla = 15.50 sq.m
-----------------------------------------------------------------
MISCELLANEOUS CONVERSION FACTORS:

1 cu.m = 35.32 cu.ft
1 pound = 4.448 Newton(force)
1 klb = 4.448 kN
1 Psi(lb/sq.in) = 6.689 Pascal (N/sq.m)
1 (lb/sq.ft) = 0.048 (kN/sq.m).
-----------------------------------------------------------------

HOW TO CALCULATE OF UNIT WEIGHT OF STEEL BARS

CALCULATION OF UNIT WEIGHT OF STEEL BARS:

After estimating it is very important  to know the unit weight of steel bars, because we estimate as 100 meter 20mm dia bar or 100 feet 16mm dia bar, etc.
But steel bar suppliers will not understand this notation, they measure the steel bars in weight. So we have to order them in kg or quintal or ton. In this article, we will discuss how to calculate unit weight of steel bars of different diameter.

The formula is W = D²L / 162

where,

W = weight of steel bars.
D = Diameter of steel bars in mm.
L = Length of bars in meter.

Example 1 : Calculate the weight of 60 meter long 12mm dia bar.

Here, D = 12mm.
L = 100m.
We know that, W = D²L / 162

W = 12² x 60/162 = 53 kg 

Weight of 60 m 12mm dia bar is 53 kg.

Let's look for another example.

Example 2 : Calculate the weight of 100 m 16mm dia bar.

Here, D = 16mm

L = 100m

W = 16² x 100/162 = 158 kg 

If we put 1meter length for each diameter of steel bar in the formula then we will get the unit weight.

• 10mm dia bar = 10² x 1/162 = 0.617 kg/m
• 12mm dia bar = 12² x 1/162 = 0.888 kg/m
• 16mm dia bar = 16² x 1/162 = 1.580 kg/m
• 20mm dia bar = 20² x 1/162 = 2.469 kg/m

If we multiply the length of bars with this unit weight we will get the total weight of steel bars.

For example, total weight of 1000 meter long 20mm dia steel bar is,

1000 x 2.469 = 2469 kg.

Using the same method we can calculate the unit weight of different steel bars.

Here I have calculated in meter but we can also calculate in foot. To calculate in foot we have to use the following formula:

W = D²L / 533

Where, 
D = Diameter of bars in mm.
L = Length of bars in foot.

TOP 10 REQUIREMNETS TO BE A SUCCESSFUL CIVIL ENGINEER

CIVIL ENGINEERING REQUIREMENTS:

THE FOLLOWING ARE THE TOP 10 REQUIREMENTS OF CIVIL ENGINEERING TO BECOME A SUCCESSFUL CIVIL ENGINEER:

1.TESTS OF A  BUILDING MATERIALS:

A good civil engineer should have proper knowledge of different tests of building materials. Some important test are listed below.

Concrete Test:

• Slump test
• Compression test
• Split tensile test
• Soundness test etc.

Soil Test:

• Core cutter test
• Compaction test
• Sand replacement test
• Triaxial test
• Consolidation test etc.

Bitumen Test:

• Ductility test
• Softening point test
• Gravity test
• Penetration test etc.

2.INVESTIGATION OF SOIL:

Various soil tests are conducted to determine the settlement and stability of soils before starting a construction. So as a civil engineer, you should have enough knowledge of these tests which are performed at the site.

3.USAGE OF SURVEY INSTRUMENTS:

Usage of survey instruments like the total station, theodolite etc is also a mandatory knowledge for every civil engineer. These instruments are used for marking and measurements.

4.STANDARD CODES USAGE IN CONSTRUCTION:

Every country has their standard safety specifications (eg: IS code) for construction related works. All new construction should be done by following all the rules and procedure mentioned in the standard codes. Otherwise, chances of failure of a structure will be always high.

5.BAR BENDING SCHEDULE:

Bar bending schedule is an essential chart for civil engineers. It provides the reinforcement calculation of RC beam such as cutting length, type of bending, the length of bending etc.

6.DRAWINGS AND DESIGNS:

Drawings and designs are the primary keys of an ongoing project. It provides all the required specifications of that project. Every site engineers should have the analyzing power of such drawings and designs.

7.ESTIMATION AND BILLS:

Estimation and bills should be prepared by a civil engineer in a construction project. So one should also have a good knowledge in estimation and bills to become a successful civil engineer.

8.QUALITY CONTROL:
 
Quality control ensures the profit of a project by reducing the extra costs. So you must have a basic knowledge about quality control.

9.ON FIELD MANAGEMENT:

Knowledge of form-work, concreting, safety measures etc is also a key aspect of a successful civil engineer.

10.COORDINATION WITH LABOR:

As a civil engineer, you must know how to deal with labors in a site. Interacting with and also managing the labors in a site is much more important.

TYPES OF DRAWINGS USED IN BUILDING CONSTRUCTION

TYPES OF DRAWINGS USED IN BUILDING CONSTRUCTION:

Drawings are the most important things we need to start any construction project. There are different types of drawings for different purposes. In this article, we will discuss different types of construction drawings (also known as Working Drawing). Construction drawings provide detail measurements and clear section of every building parts. After reviewing, the drawings are justified and modified and finally approved for construction.The different types of construction drawings are listed below.

1.ARCHITECTURAL DRAWING:

This type of drawing provides complete view of a building. It demonstrates the location of building parts where they will be placed. There are different types of architectural drawings with different names such as plan, elevation, section etc.

2.STRUCTURAL DRAWING:

As the name suggests, this type of drawing provides information about structure, like strength of different structural elements, structural materials, grade, size and placement of reinforcement etc. 

3.ELECTRICAL DRAWING:

This type of drawings provide the details and location of electrical wiring, fixtures,sub-station etc. The electrical load calculation is also given in the drawing. 

4.PLUMBING AND SANITARY DRAWING:

These drawings give the location of sanitary, piping for water supply system, fixture, and the process to connect every fixture etc.

5.FINISHING DRAWING:

 This types of drawings contain the details of finishing and appearance of the building such as marbles, tiles etc.

HOW TO CALCULATE CEMENT BAGS IN 1 CUBIC METER

PROCEDURE TO CALCULATE CEMENT BAGS IN 1 CUBIC METER:

Let us consider the nominal mix is 1:2:4

Loss of cement is considered as 2%

Output of mix is considered as 67%

To achieve 1cum output, we need 1/0.67 = 1.49 say 1.50 cum dry mix.
      
Now add wastage of 2%, i.e (1.50 + 0.02) = 1.52 cum.

Volume of cement = (Cement / Cement+Sand+Aggregate) x Total material 
                = (1 /1+2+4) x 1.52
                = 0.2171 cum

As we know, the density of cement is 1440 kg/cum and 

Weight of 1 bag cement = 50 kg.

Therefore Volume of 1 bag cement = (Weight of 1 bag cement / Density of cement)
                                                        = 50 / 1440 = 0.0347 cum.

∴ No. of cement bags required in 1 cubic meter = 0.2171 / 0.0347 = 6.25 bags.

Note: You can use the same formula for calculating cement for other nominal mixes.

DIFFERENT TYPES OF ESTIMATES IN CIVIL ENGINEERING

DIFFERENT TYPES OF ESTIMATES:

There are different types of estimates which are as follows:

1.PRELIMINARY OR APPROXIMATE OR ROUGH ESTIMATE:

This is an inexact estimate to find out a rough cost in a short time which enables the authority concerned to consider the financial aspect of the scheme, for according sanction to the same. Such an estimate is framed after knowing the rate of similar works and from practical knowledge in various ways for various types of works such as:

• Plinth area or square-meter method
• Cubic rate or cubic-meter method
• Service until or until rate method
• Bay method
• Approximate quantities with bill method
• Cost comparison method
• The cost of materials and labor.

2.DETAILED ESTIMATES:

This consists of detailed particulars of the quantities, rates, and costs of all the materials required for satisfactory completion of a  project.

Quantities of all materials of work are calculated according to their respective dimensions on the drawings on a measurement sheet. Multiplying these quantities by their respective rates in a separate sheet, the cost of  all items of work are figured out individually and then summarized, i.e abstracted (which is the detailed actual estimated cost of work). All other expenses required for satisfactory completion of the project are added to the above cost to frame  the total of a detailed estimate.

A detailed estimate is accompanied by

• Report
• Specifications
• Detailed drawings showing plans, different sections, Key or Index plan etc.
• Design data and calculations
• The basis of rates  adopted in the estimate.

Such a detailed estimate is prepared for technical sanction, administrative approval and also for the execution of a contract with the contractor.

3.QUANTITY ESTIMATES OR QUANTITY SURVEY:

This is a complete estimate or list of quantities for all materials of work required to complete the concerned project. The quantity of each individual item of work is worked out from respective dimensions on the drawing of the structure. To find the cost of an item its quantity is multiplied by the rate per unit for that item. The purpose of the bill of quantities is to provide a complete list of quantities necessary for the completion of any engineering project and when priced gives the estimated cost of the project.
 

TOP 10 BRANCHES IN CIVIL ENGINEERING

TOP 10 CIVIL ENGINEERING BRANCHES:

The top 10 civil engineering branches are as following:

1.CONSTRUCTION ENGINEERING:

 Construction engineering is one of the important branches of civil engineering.This branch deals with the planning, construction, and maintenance of structures such as buildings, bridges, towers etc.

2.GEOTECHNICAL ENGINEERING:

  
Geotechnical engineering is about analyzing the subterrestrial soil, rock, foundation etc.
Sub-branches of Geotechnical engineering:

• Soil Mechanics
• Soil Dynamics
• Foundation Engineering
• Rock Mechanics
• Pavement Engineering

3.STRUCTURAL ENGINEERING:

Structural engineering is the branch which deals with the design and structural analysis of structures such as buildings, bridges, etc.

4.SURVEYING:

In this branch of civil engineering, surveying and leveling are done to locate and measure the property lines, layout of buildings, roads, bridges, etc. for construction.

5.TRANSPORTATION ENGINEERING:

Transportation engineering deals with the design, construction, and maintenance of various transportation facilities such as highways, railways, airports, parking lots, traffic signal control systems etc.

6.ENVIRONMENTAL ENGINEERING:

This branch is related to study of pollution, environment-friendly designs, water treatment plants etc.

7.EARTHQUAKE ENGINEERING:

Earthquake engineering is one of the latest additions in civil engineering. It deals with the seismic forces, designs and construction of earthquake resistant structures.

8.WATER RESOURCE ENGINEERING:

This branch of civil engineering interacts with the design and construction of hydraulic structures such as dams, canals, water distribution systems etc.

9.MUNICIPAL ENGINEERING:

Municipal engineers work with the urban or city governments for planning and management of township.

10.MATERIAL ENGINEERING:

Material engineering is the study of the strength of materials, properties of materials etc which are used in construction work and other ceramics.    

RCC FRAMED STRUCTURE BUILDINGS

RCC FRAMED STRUCTURE:

Due to lower compressive strength of bricks (For 1:2:4 cement concrete works), the width of load bearing walls for the building having more than four story becomes extremely thick and for such cases, RCC framed structures are suitably adopted. Framed structures are generally of two types:

1.Steel Frame
2.RCC Frame

In this article, we will discuss various advantages of RCC framed structure which are as following:

1. In RCC framed structure building the floor area is normally 10 to 12% greater compared to a load bearing walled building.Hence, this type of building is preferably economical where the value of land is very high.
2. It is very easy to alternate the interior plan of a room, bathroom, W.C etc. by changing the actual position of the partition walls which ultimately gives more freedom in planning.
3. Monolithic construction can be adopted for resisting shocks and vibrations more effectively than load bearing walled buildings.
4. Normal earthquake effects can also be resisted by providing required further design.
5. Faster construction work saves time, early finishing.
6. No matter the soil is soft or hard, RCC framed building can be established anywhere.
7. Maintenance cost is also minimum which can be ignored. 

CLASSIFICATION OF STAIRS

TYPES OF STAIRS:
   Depending on the various arrangement of steps, stairs can be classified under following categories:

1.STRAIGHT STAIR:

I

In this stair, all the steps are continuously along in one direction. One flight may be split into one or more than one flight by interposing a landing. This stair can be used where narrow and long space is available for a staircase such as entrance, porch etc.

2.DOGGED-LEGGED STAIR:

This stair consists of two straight flights of steps with direct turns between them. This stair is very useful where the total width of the stair is just twice the width of the steps.

3.OPEN NEWEL STAIR:

  This type of stair consists of two or more flights arranging a well or opening between the backward and forward flights. When all the steps are difficult to arrange in two flights, a short third flight 0f 3 to 6 steps may be provided along the direction perpendicular to the hall. Open newel stair is mostly adopted in the lift.

4.GEOMETRICAL STAIR:

  This is another type of newel stair where the open well between the forward and the backward flight is curved. This stair may contain different geometrical shape. Here the change in direction is achieved by using winders.

5.CIRCULAR STAIR:

In this type of stair, all the steps radiate from a newel or well hole, in the form of winders. The circular stair is adopted at the back side of a building to access its various floors.

6.SPIRAL STAIR:

 Spiral stair is very similar to circular stair. It consists of individual steps or treads,connecting to a center column. The overall  diameter of the stair may range from 1 to 2.5m.

7.QUARTER-TURN STAIR: 

The quarter turn stair can be defined as the stairs that are turned at 90 degrees with the help of level landing.

8.BIFURCATED STAIR:

This type of stair is provided in modern public buildings. In this stair, the flight is so arranged that there is a wide flight at the start which is sub-divided into narrow flights at the mid-landing. The narrow flights start from either side of the mid-landing. 

SPECIFICATIONS OF PLASTERING

The general specifications of plastering are as follows:

1. Plastering is the finishing coat which protects the masonry and gives a decent look.It also enhances the hygienic conditions in the building.
2. The reference marks (BUNDAS) should be made on the wall in 2" to 3" diameter before starting the plastering work.
3. Cement and sand mortar is used in plastering which comprises of different thickness according to the requirement of the site.
4. Plastering should be done with cement mortar ratio of 1:3, 1:4, 1:6 etc. as per the requirements of the work.
5. The plaster should be in straight line, leveled, plumbed and the joint must be in right angle.
6. Before starting the plaster, the surface should be raked and properly cleaned by wire brush and it should be wet for 24 hours.
7. Door and window frames, water supply lines,electric fittings should be fitted appropriately before starting the plastering work. They should be laid as per the drawings.
8. All unnecessary cement mortar should be removed from the frames and electric fittings instantly after finishing the plaster.
9. Curing the plastered surface should be done properly. It should be cured at least for 7 days to get desired strength.

CALCULATION OF BRICKS IN A WALL

Estimation of building materials is essentially required before starting a new construction project.
Today we are going to see the easiest method to calculate the required number of bricks in a wall.So let's start from the beginning.

REQUIRED DATA:

• Volume of wall
• Volume of a standard brick
• Details of openings in the wall 

PROCEDURE:

1. First calculate the volume of wall to be built. 

Let us assume,
The length of the wall(L) = 10 foot.
The height of the wall (H) = 10 foot.
Thickness of the wall (B) = 1 foot.

 Calculate the volume of the wall by multiplying the length,height,and thickness.
∴Volume of the wall = L*B*H

∴ Volume of the wall = L*B*H = 10*10*1 = 100 Cu.F

2.Calculate the volume of the brick

The standard size of the brick is 190mm*90mm*90mm (IS standard) and with the mortar joint, it becomes 200mm*100mm*100mm.

L = 200mm = 0.656168 ft.
B = 100mm = 0.328084 ft.
H = 100mm = 0.328084 ft.
 
∴Volume of the brick = L*B*H = 0.656168*0.328084*0.328084 = 0.0706 Cu.F

3. To find out the total nos. of brick, divide the volume of wall by the volume of the brick.

∴No. of bricks required = 100 / 0.0706 = 1416 no. of bricks.

NOTE:
1. Consider 10% wastage of bricks.
2. If the wall has any openings, subtract the volume of the openings from the volume of wall and then divide it by the volume of brick.


 

USEFUL CIVIL ENGINEERING TIPS FOR SITE ENGINEERS

Following are the basic tips you should be remembered while working on construction sites:

1.GRADE OF CONCRETE:

• M5 - 1:4:8
• M10 - 1:3:6
• M15 - 1:2:4
• M20 - 1:1.5:3 
• M25 - 1:1:2 

2.CLEAR COVER TO MAIN REINFORCEMENT:

• Footings - 50mm
• Raft Foundation(Top) - 50mm
• Raft Foundation(Bottom) -75mm
• Raft Foundation(Side) - 75mm
• Beam - 25mm
• Strap Beam - 50mm
• Column - 40mm
• Slab - 15mm
• Flat Slab - 20mm
• Stair Case - 15mm
• Retaining Wall - 20 to 25mm
• Water Retaining Structures - 20 to 30mm .

_______________________________

1. Maximum Water Absorption by bricks - 15% 
2. Compressive Strength of Bricks - 3.5 N/mm^2 
3. Density of Bricks - 1600 to 1920 Kg/m^
4. Minimum Thickness of Slab - 125mm
5. Dimension Tolerance for Cubes - +2 
6. Maximum Freefall of Concrete - 1.50m
7. Laping should not be use for the bars having larger dia than 36mm 
8. Binding wire required for steel reinforcement - 8Kg per MT
9. Maximum chair spacing - 1m
10. Minimum dia should be ised in dowels rod - 12mm
11. Hooks for Stirrups(1side) - 9D
12. No.of.Stirrups=(clear span/spanning+1)
13. Length of main steel in cantilever anchorage - 69D 
14. Minimum no.of bars in square column - 4
15. Minimum no.of bars in circular column - 6 
16. Minimum dia of main bars and distributors in the slab - 1/8 of slab thickness.

All reinforcements should be free from mill scales,loose rust,and coats of paints,oil or anyother substances.

3.SETTING TIME:

• Initial setting time should not be less than 30minutes.

• Final setting time should not be greater than 10hours.

4.REQUIRED CURING DAYS:

• Super Sulfate Cement - 7days
• Ordinary Portland Cement - 10days
• Cement with minerals and admixtures - 14days

5.SLUMP VALUE(IS-456):

• Lightly Reinforced Concrete - 25 to 75mm
• Heavily Reinforced Concrete - 75 to 100mm
• Trench Fill - 100 to 150mm(for in-situ & tremie)

GENERAL PRINCIPLES SHOULD BE OBSERVED IN BRICK MASONRY

The points to be observed in supervising brick masonry construction are as following:
1. The bricks to be used should fulfill all the requirements of the specification of the work. The bricks should be sound, hard, burnt well with uniform color, shape, and size.
2. The bricks should be immersed in fresh water at least for 2 hours before using in masonry.
3. Do not use broken bricks unless they are essential for making good bonds.
4. The bricks should be laid on their proper bond. The frog of the bricks should be kept upward.
5. Brick bats should be avoided.
6. The thickness of the joints should not exceed 13 mm.
7. The masonry walls should be always truly vertical and verticality should be checked continuously using a plumb bob.
8. Brickwork should be raised uniformly. Any part of the masonry should not be raised more than 90 cm to the rest of the masonry work.
9. The work should be raked back in successive courses if it is to be constructed later.
10. In masonry work, large voids should not be filled only with mortar. It is uneconomical.
11. Cement mortar should be used to enclose all the iron fixtures of doors and windows.
12. To achieve easy and adequate bond for plastering and pointing, the facing mortar joints should be raked for a depth of 13-19 mm when the mortar in the joint is green.
13. The finished brick masonry should be cured at least for 7 days.
14. Any brick masonry wall should not be constructed more than 1.5 meters in a day.
15. In brick masonry piers, buttresses, counterforts etc should be constructed along with the main walls, maintaining a proper bond between them.
16. Suitable scaffolding should be used to carry out masonry work at higher levels.
The scaffolding should be made by giving one end of horizontal bullies into the new masonry work and secured to it properly.