Civil Engineering Basic Knowledge

Abbreviation, Full Forms, and Terminology.

[su_table responsive=”yes” alternate=”no”]

Name	Description
ASTM	American society for testing materials
C/C	Center to center distance
DL	Development length
Sub-structure	Structure which is below the ground level
Super-structure	Structure which is above ground level
Elevation	View which we can see when we stand right in front of the structure on any of the sides.
Plastering	Cement, sand, and water mix applied on brick wall for smooth surface for painting.
Plinth level	Level on which the actual structure stands on
Riser	The vertical height of single step
Tread	Horizontal portion where we put our foot on which going on steps
Footing	The bottom most part of structure. These are categorized as Isolated footing, combined footing, Raft etc.
Columns	The vertical members of structure
Clear cover	Clear distance maintained from concrete face up to face of the reinforcement steel.
Effective depth	Distance from top of the concrete face upto the CG of reinforcement.
Singly reinforced section	Section of concrete member with reinforcement at only on tension face.
Doubly reinforced section	Section of concrete member with reinforcement on both tension and compression side.
Stirrups	Steel bent in closed shape of either Rectangular of circular shape.
Cantilever beam	Beam with fixed support on one side and the other end is free.
Propped cantilever	Beam with fixed support on one side and other end is with pinned support.
Pedestal	Length of the member is less than 3 times in width
One way slab	Ratio of length to width is more than 2 its one way slab
Two way slab	Ratio of length to width is less than or equal to 2 , its two way slab.
Slender column	Length to width ratio of column is more than 12 , then its slender column
Plain cement concrete	Cement concrete mix provided on the ground level over which foundations, beams are constructed.
Pile foundation	The foundation system with Piles i.e cylinder shaped reinforced concrete member.
Retaining wall	Wall constructed to retain earth
Scaffolding	Temporary structure, where work needs to be carried out at higher elevations.

[/su_table]

Construction Materials

1. Cement: Cement is essentially attained by crushing the gravels comprising lime in addition to clay. Cement is the binder that aids in the attachment of cement, sand alongside with water. Nearly of the actual significant categories of cement.

2. Aggregate: Two different type of aggregate are as follows.

1. Fine Aggregate

Fine aggregate is the material which permits finished 4.75 mm sieve then reserved on 0.075 mm sieve
Example: Sand

2. Coarse Aggregate

Coarse aggregate is the material which retains on 4.75 mm sieve.
Example: Gravel

3. Concrete: Concrete is attained by mingling cement, aggregate in addition water in accordance with a preferred mix. At this point

water to cement proportion shows a significant part.
Strength of concrete is inversely proportionate to the water-cement ratio.
Concrete is characterized by terminology as M-25. Where M is Mix and 25 is the compression strength at the 28 days allowing for
concrete cubes of 15 cm cube.
Concrete has Two setting types.
Initial Setting time is of 30 min.
Final Setting time is of 10 hrs.
The test for setting time is through by means of Vicats apparatus.
Concrete setting time can be increased or decreased dependent on environmental circumstances by means of admixtures.
Admixture for increasing the setting time is named retarder then for decreasing the setting time is named accelerator.

Any Structure Typically Consists of Following

Foundation.
Columns.
Beams.
Slabs.
Main Walls and partition walls.
Staircase.
Flooring.
Finishes – Plastering and Painting.
Boundary Wall.

Basic Loads on Structure

Self-weight of structure i.e slabs, beams, columns, walls, etc.,
Live Loads due to furniture, equipment, machinery, etc.
Wind Loads.
Seismic Loads / Earthquake Loads
Snow Loads
Hurricane Loads at some locations

List of Major Indian Codes

[su_table responsive=”yes” alternate=”no”]

Code for Reinforced concrete	IS: 456
Specifications for steel construction	IS: 800
Wind Loads on building	IS: 875
For Seismic Specifications	IS: 1893
For water retaining structures	IS: 3370

[/su_table]

Usefull Tips for Civil Engineers

[su_table responsive=”yes” alternate=”no”]

Lapping of bars	Diameter of bar is less than 36mm.
Circular column	Use Minimum 6 longitudinal bars
Thickness of slab	Minimum is 0.125m
PH value of water	More than 6 should be used for building purposes.
Compressive strength of Bricks	3.5 N /mm²
Dead Load of structure	Self-weight of Structure
Moisture content	Sand that haves more than 5% must not be used for Concrete mix.
DPC	Thickness should not be less than 2.5cm
RMC (Ready Mix concrete)	It is made at factory and transported to the site. It is used where there is a lack of space for mixing the concrete It is used where a huge amount of concrete is required for construction.
Height of floor	3 m or 10 ft
Cantilever Beam	One end is fixed support and the other end is free.
Simply supported beam	It has Minimum of two supports
PCC	It is Used on members when the tensile forces are not acting on it.
Weight of first-class clay brick and crushing strength	3.85 Kg and 10.5MN/m²
Impermeability of concrete	It is the concrete that resists the entry of water or moisture into it.
Curing Period of RCC	28 days
Minimum sill level height	44 inches
Ties	Transverse reinforcement providing in columns
Stirrups	Transverse reinforcement providing in Beams
The thermal expansion co-efficient of concrete and steel	12×10−6/°C
Number of Bricks necessary for 1m³ of Brick masonary	550 bricks
Specific gravity of Cement Specific gravity of brick Specific gravity of sand	3.16g/cm³ 2g/cm³ 2g/cm³
Standard Size of Brick	19 cm x 9 cm x 9 cm
Slope or Pitch of the stair	25 degrees to 40 degrees
Rise in stairs	150mm to 200mm
Tread in staircase	250mm to 300mm
Hook length	More than 9 * diameter of bar
Unit weight of PCC Unit weight of RCC Unit weight of STEEL	24KN/m³ 25 KN/m³ 7850Kg/m³
Volume of 50 kg cement bag	1.3cft
TMT bars	Thermo Mechanically treated bars
Length of each bar from factory	12m

[/su_table]

Concrete Basic Knowledge

The concrete must not be thrown as of a height of more than 1m.
Cube test is passed out for every 30 m3practise of concrete.
A head mason must labour 25-30 m3throughtout a day.
In manufacturing, the rate analysis for the work of labours is considered in Man Hours.
Theodolite least count is 20 Secs while Compass Least count is 30 mins.
Cement more than 3 months old cannot be used for construction.
Calculation of extra water in the concrete mix to rise setting time primes to arrangement the Cracks or honeycomb in hardened
concrete.
Vibration in freshly made concrete is completed to eliminate the air foams in a concrete mix.
The concrete can be raised to an extreme height of 50 musing Concrete Pumps.
Stirrups in Beams and Ties in Column are on condition that to grip the shear force and to save longitudinal bars in location.
The Major aim for by means of steel as reinforcement is owing to thermal expansion.
M20 grade of concrete is normally used in the construction of a slab.
Floor area engaged by 50 kg of Cement bag is 0.3 m2 and elevation of 0.18 m.
According to IS 456: 2000, Maximum diameter of bar used in the slab would not surpass 1/8th of the entire thickness of the slab.

Test of Building Materials

Civil engineers need to ensure correct information of various tests of building materials.

1. Soil Test.

Core Cutter Test.
Compaction Test of Soil.
Sand Replacement Test.
Tri-axial Test.
Consolidation Test.

2. Concrete Test.

Slump Test.
Compression Test.
Split Tensile Test.
Soundness.

3. Bitumen Test.

Ductility Test
Softening Point Test
Gravity Test.
Penetration Test.

Concrete Slump Value for Various Concrete Constructions

[su_table responsive=”yes” alternate=”no”]

Concrete Mixes	Slump range in mm
Columns and Retaining walls	75-150 mm
Beams and Slabs	50-100 mm
Cement Concrete Pavements	20-30 mm
Decks of bridge	30-75 mm
Vibrated Concrete	12-25 mm
Huge Mass constructions	25-50 mm

[/su_table]

Grades of Concrete

[su_table responsive=”yes” alternate=”no”]

Grades of Concrete	Prpostion
M5	1:5:10
M7.5	1:4:8
M10	1:3:6
M15	1:2:4
M20	1:1.5:3
M25	1:1:2

[/su_table]

Clear Cover to Main Reinforcement

[su_table responsive=”yes” alternate=”no”]

Footing	50 mm
Top Raft Foundation	50 mm
Bottom/ Sides Raft Foundation	75 mm
Strap Beam	50 mm
Grade Slab	20 mm
Column	40 mm
Shear Wall	25 mm
Beams	25 mm
Slabs	15 mm
Flat Slabs	20 mm
Staircase	15 mm
Retaining Wall	20 – 25 mm
Water Retaining Structures	20 – 30 mm

[/su_table]

Unit Weight of Different Materials

[su_table responsive=”yes” alternate=”no”]

Concrete	25 kN/m³
Brick	19 kN/m³
Steel	7850 Kg/m³
Water	1000 Lt/m³
Cement	1440 Kg/m³

[/su_table]

Development Length

[su_table responsive=”yes” alternate=”no”]

Compression	38 diameter
Tension	47 and 60 diameter

[/su_table]

Unit Conversation

[su_table responsive=”yes” alternate=”no”]

1 Cent	435.60 ft²
1 Meter	3.2808 ft
1 M2	10.76 ft²
1 Feet	0.3048 m
1 KN	100 Kg
1 kN	1000 N
1 Ton 1000Kg	10,000 N = 10 kN
1 kG	9.81 N
1 Gallon	3.78 Litres
1 Hectare	2.471 acre
1 Acre	4046.82 m²

[/su_table]

[su_box title=”FAQ” style=”default” box_color=”#333333″ title_color=”#FFFFFF” radius=”3″ class=”” id=””]

Super Structure

A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships having the degree of freedom zero (in the terms of theory of machines).

Plinth Level

What Is Plinth Level? The plinth is the part of the superstructure between the top of the tie beam at the finished ground level (the top level of the soil surrounding the structure that has been prepared and leveled before construction) and the floor level of the building( the ground floor level inside the building).

Effective Depth

Effective Depth (d) – The effective depth (d) of a reinforced concrete floor slab is the distance from the compression face to the center of the tensile steel when an element is subjected to a bending moment.

One Way Slab

One way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. The ratio of longer span (l) to shorter span (b) is equal or greater than 2, considered as One way slab because this slab will bend in one direction i.e in the direction along its shorter span.

Slender Column

Slender columns can be defined as columns with small cross sections compared to their lengths. Generally, slender columns have lower strength when compared to short columns, for a constant cross section, increasing the length causes a reduction in the strength.