Must-Have knowledge for Civil Engineers | Civil Engineering Tips

There are many activities that should be performed by civil engineers at the site and in the lab. Here we are going to discuss some important points which every civil engineer must learn and remember. These tips can also help to crack the interview. This is a kick start guide if you are joining in any company as a Civil engineer.

Civil Engineering Tips:

• ASTM Abbreviation: American Society for Testing Materials
• Grade of Concrete is denoted as Cement: Sand: Aggregate (Ex M20 Grade : 1:1.5:3)
• C/C means Center to Center Distance
• DL means Development Length
• Lapping of bars not allowed if the dia of the bar is more than 36mm.
• For circular column minimum of 6 longitudinal bars are used.
• The minimum thickness of the slab is 0.125m
• A water pH value of less than 6 should not be used for construction purposes.
• The concrete Should not be thrown from a height of more than 1m.
• The Compressive strength of Bricks is 3.5 N /mm2
• The initial setting time shall not be less than 30 minutes and the final setting time of cement is 10hours.
• Dead Load means the Self weight of Structure
• Sand having moisture content more than 5% should not be used for Concrete mix.
• DPC means the Damp Proof Course. The thickness of DPC should not be less than 2.5cm.
• A cube test is carried out for each 30m3 usage of concrete.
• RMC: Ready Mix concrete, The concrete is made at the factory and transported to the site, This type of concrete is used where there is a lack of space for mixing the concrete and used where a huge amount of concrete is required for construction.
• The height of the floor is usually 3m or 10ft (If a person asks you whats the height of 12 storied building? Ans: 3m x 12floors = 36m)
• A head mason can work 25-30m3 in a day.

• In construction, the rate analysis for the work of workers is calculated in Man Hours. (Ex: 10$ for 1 Man hour)
• Cantilever Beam has One fixed support and the other end is free, Simply supported beam has a minimum of two supports.
• PCC (Plain Cement Concrete) this type of concrete is used on members-only when the tensile forces are not acting on it.
• The weight of first-class clay brick should be 3.85 Kg. and it has a crushing strength of 10.5MN/m2
• Adding more water in the concrete mix to increase setting time leads to form the Cracks or honeycomb in hardened concrete.
• Vibration in freshly made concrete is done to remove the air bubbles in the concrete mix.
• Impermeability of concrete:  The concrete which resists the entry of water or moisture into it.
• The concrete can be lifted to a maximum height of 50m using Concrete Pumps.
• The curing Period of RCC is 28days.
• The minimum sill level height should be 44 inches.
• The transverse reinforcement provided in columns is called Ties.
• The transverse reinforcement provided in Beams is called as Stirrups.
• Stirrups in Beams and Ties in Column are provided to handle the sheer force and to keep longitudinal bars in position.

• The Prime reason for using steel as reinforcement is due to thermal expansion. The thermal expansion coefficient of concrete and steel is (approximately) same having value 12x10−6/°C

• M20 grade of concrete is generally used in the construction of the slab.
• Weight of Bar is calculated using formula D2/162 (D = Dia of the bar in mm)
• The No. of Bricks required for 1m3 of Brick masonry are 550 bricks.
• Specific gravity of Cement is 3.16g/cm3; Bricks is 2g/cm3;  Sand is 2.65g/cm3 ,
• Standard Size of Brick is 19cm x 9cm x 4 cm or 19cm or 9cm x 9 cm
• The floor area occupied by 50kg of Cement bag is 0.3m2 and height of 0.18m.
• As per IS 456: 2000, Maximum dia of the bar used in the slab should not exceed 1/8th of the total thickness of the slab.
• IS 456:2000 is Code of Practice for Plain and Reinforced Concrete
• IS 800:2000 is code of Practice for General steel construction
• The slope or pitch of the stair should be between 25 degrees to 40 degrees.
• The rise in stairs is in between 150mm to 200mm.
• Tread in the staircase is in between 250mm to 300mm.
• Hook length should not be less than 9D (Dia of Bar)
• Unit weight of PCC is 24KN/m3, RCC is 25 KN/m3, Steel is 7850Kg/m3
• The volume of the 50kg cement bag is 1.3CFT.
• Theodolite least count is 20Secs whereas Compass Least count is 30mins.
• TMT bars: TMT means Thermo Mechanically treated bars
• Cement more than 3 months old cannot be used for construction
• The length of each bar from the factory is 12m. 

Must Remember the Concrete Mix ratio of Different grades of Concrete at least till M20 grade of concrete

Concrete Grade	Mix Ratio
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
M30, M35, M40, M45, M50, M55, M60, M65, M70	Design Mix

Know about the Slump value of Concrete for Different concrete works

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

Mechanization in Construction Industry- Motivations, and Advantages

Mechanization is the process of shifting from working largely or exclusively by hand to do that work using machines. The construction projects are becoming more demanding and complicated in construction and delay of projects would arise if the conventional construction method is used.

Delays in construction are costly and have prompted developers to embrace mechanization. Construction machinery is used in order to achieve larger output, cost-effective, execution of work that is not feasible by manual efforts, reduce the amount of heavy manual work which would cause fatigue, maintaining large output, and finalize projects on time.

Mechanization is based on rented construction equipment is cost-effective. construction equipment when rented can be exactly to match the requirement. For rented equipment, time to make the equipment ready for operation is important.

Motivations for Mechanization of Construction Industry

• The work can be done speedily which avoids the time and cost over-runs.
• A large number of materials can be handled, so the size of the project can be increased
• The complex projects involving high-grade material.
• High-quality standards can be maintained.
• A time schedule can be kept.
• Optimum use of material, manpower, and finance.
• Shortage of skilled and efficient manpower.
• To control the duration and cost implications by using mechanized equipment over the Conventional method, which can be used in the planning of construction projects.
• Lower insurance costs for builders.
• Easier and safer work for construction workers.
• Increased sustainability over a building’s lifetime.
• Little to no building-site construction waste.

Applications of Construction Mechanization

1. Highway projects
2. Irrigation
3. Buildings
4. Power plant and other applications

Fig. 1: Highway Construction

Fig. 2: Mechanization of Building Construction

Sources of Construction Mechanization

Fig. 1 illustrate the source of equipment from which construction equipment can be selected and obtained.

Fig. 3: Sources of Equipment

Factors Affecting Selection of Construction Equipment

1. Availability of equipment.
2. Suitability of job condition with special reference to climatic and operating condition.
3. Uniformity type; easier operation and maintenance, easy exchange of spare parts and operating personnel.
4. Size of equipment.
5. Use of standard equipment; made by several companies so that easy purchase and delivery.
6. Country of origin; If importing foreign exchange facilities should be easily available.
7. The unit cost of production – the cost of running.
8. Availability of spare parts and selection of manufacturers.
9. Availability of local labor for operations.
10. Function to be performed.
11. The capacity of the equipment.
12. Method of operation and its limitations.

Common Types of Construction Equipment

• Earthmoving equipment
• Hauling equipment
• Hoisting equipment
• Conveying equipment
• Aggregate and concrete production equipment
• Pile driving equipment
• Tunneling and rock drilling equipment
• Pumping and dewatering equipment
• Tower cranes
• Laser Screeding Paving machine
• Plastering machine
• Bar cutting machine
• Bar straightening
• Core drill machine
• Laser screed Machine
• Arial platform work lifting machine

Fig. 4: Tunnel Construction Machine

Fig. 5: Laser Screed Machine

Advantages of Construction Mechanization
Economical
Improve construction quality
Increase the safety of construction conditions
Enhance the speed of construction
Feasibility
Disadvantages of Construction Mechanization

1. Loss of Skill

The craftsman with the superior skill had disappeared. Such skill is no longer necessary. The only type of skill that is needed now is to run the machines.

2. Dependence

Machinery has increased our dependence on others. We depend on our water and light on the satisfactory working of water-works and the power-house.

A small flaw would result in the supply of these necessaries being cut off at any time. This may mean not only an inconvenience but a serious dislocation of normal life.

3. Insanitary Surroundings

Big factories pollute their surroundings and make them filthy and unsanitary. This has led to moral degradation and physical deterioration.

4. Over-specialization

Machinery leads to too much specialization. This overspecialization increases the risk of unemployment and cramps the worker physically.

5. Class-conflict

The use of machinery is responsible for class-conflict—the capitalist on one side and the laborer on the other.

6. Unemployment

It creates unemployment because one machine can take the place of several men.

What is Gabion? Its Types, Applications, and Advantages

What is gabion?

Gabion is a welded wire cage or box filled with materials such as stone, concrete, sand, or soil. So, the gabion is a partially flexible block construction used for slope stability and erosion protection in construction. Various types of gabions are constructed and used in different engineering constructions.

Sometimes, live rooting branches may be placed between the rock-filled baskets which improve the durability and stability of the gabion. This article presents a gabion definition, types, applications, and advantages.
Gabion wire mesh properties

Wire mesh used to manufacture the cage of gabion shall pose certain properties otherwise it might not serve its purpose properly. Table 1 provides the desired properties of the gabion wire mesh.

Table-1: Gabion wire mesh properties

Raw material Gabion wire mesh properties
Technical properties Unit Descriptions Tolerances
Mesh mm 50×70, 60×80, 80×100, and 100×120 —
Maximum wire thickness mm 2-5 0.05
Amount of covering gr/m2 30-300 5
Tensile strength MPa 350-2000 2
Elongation (25cm long) — 10% —
Zinc coating strength Turns 5 Shall not break or crack



Fig. 1: Wire mesh boxes for gabions

Types of Gabions

There is a number of gabion configurations that can be selected based on their cost and function. Common types of Gabion are as follows:
1. Gabion baskets
It is a net wire mesh that produced in box-shaped and in different sizes.
Used in highway and railway works.
It would be economical unless filling materials are not available from quarries near the project site.

Fig.2: Basket gabion

2. Gabion mattresses
Gabion mattresses, also known as reno mattresses.

Gabion mattress's height is shorter than the other types of measurements as it might be observed from Fig. 3.
It is employed in the channel coating for preventing erosion. So, it tackles wave and erosion induced velocity.
The common size, 6 m long by 2 m wide by 0,3 m high.

Fig. 3: Gabion mattress

3. Gabion sacks
This type of gabions is formed quickly.
It has a porous and flexible structure.
Gabion sacks are usually used in hydraulic works in emergency conditions.


Fig. 4: Gabion sacks

4. Gabion wire mesh
It is utilized to keep the possible rock and stone fall on the highway and railway surfaces.
Gabion wire mesh maintains the stability of the slope close to the highway and railways.
It is applied for anti-erosion to the slope.
It enhances embankment soil strength in combination with geogrid reinforcement.

Fig. 5: Gabion wire mesh used to prevent rockfall from highway slopes

5. Decorative Gabion Elements
It is used indoor and outdoor decoration, garden design and landscaping.
Gabion elements offer a suitable environment for the growth of plant roots


Fig. 6: Decorative gabion elements

Applications of gabions

Gabions are used in several engineering projects and serve various purposes. common applications of gabions are as follows:
Retaining structures such as retaining walls (Fig. 7), revetment and toe walls to embankments and cuttings.
Corrosion prevention structures, for instance, sea walls, riverbank defenses, canal banks (Fig. 8), dams, weirs, groins and for the protection of reservoirs and lakesides.
cylindrical metal gabion is used for dams or in foundation construction.
It is employed as a noise barrier.
Gabions are also used as temporary floodwalls.
It is utilized to change the direction of the force of floodwater around the weak structure
Stepped gabions improve energy dissipation in channels.
Finally, it is used for aesthetic purposes

Fig. 7: Gabion retaining wall for road embankment



Fig. 8: Gabion mattresses used for covering channels to prevent erosion



Fig. 9: Use of gabions in landscaping



Fig. 10: Gabions used for aesthetic purpose

Advantages of gabions

1. Durability


Gabion has a very high resistance to atmospheric corrosion because of the well-bonded zinc coating on the wire and its ability to support vegetation growth.

2. Flexibility

This feature permits the gabion to settle and deform without failure and loss of efficiency. Specifically, when unstable ground and moving water are encountered.

3. Permeability

It provides automatic and easy drainage which eliminates the need for the installation of drainage pipes.

4. Strength

Gabions are satisfactory strong that is it is capable of resisting flood force, torrential force, and ice and earth pressure.

5. Economical

It is more economical in terms of both material and labor in comparison with other gabion alternatives.

6. Environmentally friendly

Recycled materials can be placed into the gabion cage. The gaps in the soil between filling materials allow the plantation to grow over time. Gabion elements are not affected by natural phenomena.

Pre-Cast Concrete Walls – Types, Connections, and Advantages

Precast concrete walls are constructed by casting concrete in a reusable wall mold or form which is then cured in a controlled environment, transported to the construction site and lifted into place. The main function of the precast walls is to speed up the construction process.

Fig 1: Erection of Precast Concrete Wall.

In this article, we discuss about the types, connections, characteristics, and advantages of precast concrete walls.
Types of Precast Concrete Wall

1. Cladding or Curtain Walls
The cladding or curtain walls are the most widely used precast wall for building envelopes. They are non-load bearing walls intended for the use to oppose the wind and encase the space. This type of precast wall incorporates divider boards, window divider units, spandrels, mullions, and section covers.

2. Load-bearing Wall
Load-bearing wall units oppose and exchange loads from different components and cannot be removed or dismantled without influencing the quality or dependability of the building.

Fig 2: Load Bearing Pre-Cast Concrete Walls

3. Shear Walls
Shear walls are utilized to give a parallel load opposing framework when joined with stomach activity of the floor development. The viability of precast shear dividers is generally needy upon the board-to-board associations.

Types of Connections in Precast Concrete Walls

1. Bolted Connections
The bolted connections are a simplified and fastest method of erection operation. The final alignment and adjustment can be made later without tying up crane time. The bolting should be in accordance with the erection drawings, using material specified by the designer.

2. Welded connections are the most common and typical connection used in the erection of precast concrete. These connections are structurally efficient and adjust easily to varying field conditions.
The connections are usually made by placing a loose plate between two structural steel plates that are embedded both in the cast-in-place or the precast concrete panel and welded together.

3. Dowel/Anchor Bolt Connections 
In a dowel connection, the strength of dowels in tension or shear depends on dowel diameter, embedded length, and the bond developed. The threaded anchor bolts and rebar anchor dowels that protrude from the foundation are the critical first connection to precast members.

Structural Design Aspects
The precast walls are designed as blind divider or facade which does not carry any load. Anyhow, the precast walls must oppose parallel loads conferred on it due to self-weight, winds, and quakes.

It is critical to assess the plan, specifying and erection of precast walls to abstain from forcing undesirable burdens onto the walls. Loads such as erection, affect, and development related, and transportation of the precast walls are to be considered in the design phase.

The joints between the walls must be sufficiently wide to suit warm extension and differential developments due to season variations. The divider hole space and go down divider which is secured with a water-safe film give an optional line of assurance against water infiltration into the building.
Characteristics of Precast Concrete Walls

1. Thermal Resistance
The precast walls infer their warm execution attributes basically from the measure of protection set in the depression or inside the reinforcement divider, which is ordinarily a metal stud divider.

2. Moisture Protection
The protection for the moisture in the precast walls is of high importance as the structural members such as columns and beams are not structurally connected with the precast walls.

The sealer or the joint seal used in the connections and joints to prevent the moisture from entering the building. To keep the uniformity of precast walls and the sealants, pigmented sealants are used.

3. Fire Safety
The precast walls are manufactured with concrete which has good fire-resistant material.

3. Acoustics
A precast wall with a veneer will give comparative execution with respect to sound transmission from the outside to the inside of the building.

4. Durability
The durability parameter of the precast walls is the same as that of concrete. Anyhow, the durability depends on the type of connections made with the structural member.

Any irregularities in the member can be rectified by sandblasting, uncovering total, corrosive washing, hedge pounding, or different methods.

5. Maintainability
As the walls are manufactured with concrete, which does not need any maintenance. The connection, sealants, anchorages, and accessories used in the precast walls need regular maintenance.

Fig 3: Pre-Cast Concrete Wall

Advantages of Precast Concrete Walls

Precast concrete walls act as thermal storage to delay and reduce peak thermal loads.
The precast concrete wall is used as an interior surface which saves time and money by eliminating the need for separate stud framing and drywall costs.
The precast concrete wall can be used as load-bearing structures and will save costs by eliminating the need for an additional structural framing system.
Precast concrete walls can be designed to be reused for future building expansions.
Precast concrete’s durability creates a low maintenance structure, which stands up to harsh climate conditions.
Precast concrete colors and finishes can be achieved through the use of various aggregates, cement, pigments and finishing techniques.
Precast concrete wall panels can utilize a thin brick veneer that can achieve a traditional appearing facade.
Precast concrete walls can be produced with textures including form liner shapes, artwork, and lettering to provide distinctive accent treatments.
Precast concrete wall panels can have electrical boxes and conduit cast into the panels, to provide flush electrical fixtures on walls that are not to be framed out.

How Do Engineers Build Structures Underwater?

Building structures underwater requires some interesting engineering. 

Have you ever looked at a large bridge or other structure whose foundation was rooted underwater and wondered how engineers ever went about constructing it or will ever fix it? When construction needs to take place somewhere that is submerged underwater, engineers use a series of large driven piles into the waterbed called cofferdams to create a dry workplace.

The way cofferdams are built: 

In terms of geotechnical engineering, the process isn't as simple as just pushing walls into the ground, engineers have to carefully design the structure to not flood and keep the workers inside safe from collapse. Most traditionally you would see cofferdams in the construction process of support piers for bridges, but they can be used in a wide variety of aqueous engineering

The piles of a cofferdam are driven into the earth in whatever formation necessary to a specific depth. When water is on one side of a wall and water is pumped out of the other side of the wall, this creates a hydraulically unstable system which can cause water to seep up through the ground.

Without getting too complex into the geotechnical engineering of this hydraulic phenomenon, there is a depth at which a wall can be driven into the ground that will keep water from seeping to the other side of the wall – typically defined by soil type and water table. The piles used in cofferdams are usually driven into the surface at a minimum of this calculated height in order to keep water out.

Removing the water from the structure:

Once the entire cofferdam is in place, pumps are used to extract the water interior to the dam structure, ultimately creating a dry workspace. Sometimes, getting the piles that make up the cofferdam to a necessary depth on the lake/ocean/river floor is simply too expensive or impractical. In cases like this, a series of pumps are set in place to constantly pump out excess water as it seeps into the cofferdam structure.

These structures are used very commonly when constructing dams, piers for bridges or other forms of aquatic engineering. While it may seem that having such a large work area under the surrounding water level may be dangerous, and it is, it's not as dangerous as you may think. Work inside of cofferdams is usually only allowed under the most pristine conditions when the water is generally static. In these states, failure modes of the pile dam are slow and predictable in nature. To help fight against these slow failures as well, a series of primary or backup pumps can kick into overdrive to help keep the inside of the cofferdam dry until crews can evacuate.

When ships need to be repaired, engineers will also use cofferdams as a sort of dry-dock to isolate the ship from the water and repair it where it sits. This is typically done on larger ships where it would otherwise be impossible to lift the ship out of the water. So, for example, when a cruise ship is lengthened or expanded, engineers will construct a cofferdam around the ship and pump out the water, allowing for workers to have a dry work area. It is important to note that cofferdams are not cheap, but for the projects where they are used, they are the only construction option.

History of cofferdams:

Cofferdams are rather old when it comes to underwater construction vice that there aren't really any other ways to build underwater. The origins of these structures date back to the Persian Empire where they began as earth cofferdams.

These early structures were made essentially how you might think, with earthen walls being built up, the water being bucketed out, the structure being built, then the earth walls removed. It was rather tedious, dangerous and time-consuming, but it did the trick.

The next innovation in cofferdam engineering was made by the Romans. Roman engineers used woodpiles that they drove into waterbeds to wall off underwater areas. This was particularly an impressive feat considering the function was similar to modern steel cofferdams, yet the Romans were able to accomplish it with wooden supports.

In what seems like a step back in the engineering of cofferdams, the next innovation was to move to sandbags, which didn't occur until the late 19th century. During the Napoleonic wars, people began using sandbags to control water. The bags were initially used to protect troops but eventually began being used to control the water by building quick dams. While not the traditional use of cofferdams, these early sandbag dams allowed for troop movements while also offering the added benefit of protection from gunfire.

Steel sheet pile cofferdams:

Finally, after the long history of cofferdams in construction, in the early 1900s, steel cofferdams were first invented by a German engineer. These first steel dams utilized interlocking U shaped steep to control the water flow and are much like what we still see in use today. This was really the final major innovation in the history of Cofferdams as today, we just see minor proprietary changes in the wall interlocking technology.

Top 10 Most Impressive Civil Engineering Projects

By M. Naeem Nekmal

Throughout history, numerous incredible engineering projects have been established and completed. From the earliest annals of history to modern times, there are numerous creations that showcase our ability to realize an incredible constructive vision. While every engineer or anyone who appreciates structures may have their own opinion on what engineering project is most impressive, it can be assumed that these men would be placed at the top:

Great Pyramid of Giza: This incredible creation consisted of two and a third million stone blocks, which required the constant labor of thirty thousand laborers to build.

Great Wall of China: What many people do not know about this enormous five thousand and a half-mile long wall is that the mortar used in its construction is made of rice flour.

Aqueduct of Segovia: These amazing aqueducts are made without the use of mortar, and are so well preserved that it is still in use today.

Brooklyn Bridge: Was the first suspension bridge to use steel in its cables.


Panama Canal: This man-made canal was designed to connect the Atlantic and Pacific oceans to provide trade ships with a passage between North and South America.


Hoover Dam: Named one of the Seven Wonders of the World, the dam generates four billion kilowatt-hours of electricity for use.


Golden Gate Bridge: This historic wonder connects San Francisco to the rest of the bay, and is made up of six hundred thousand rivets.


English Channel Tunnel: A thirty-one-mile long tunnel, the English Channel Tunnel currently contains the longest portion of any tunnel housed under the sea.


Burj Khalifa: Interestingly enough, one of the biggest setbacks to face the construction of the Burj Khalifa, the world’s tallest building, was one hundred and sixty kilometers per hour winds that required special testing to determine the safety of the construction material.


Qingdao Haiwan Bridge: It is currently the longest bridge in the world and was specially designed to withstand earthquakes and typhoons.

ځوانانو ته یو څو خبری

Personally I love Books. There are those that make you think, make you laugh, motivate and inspire you. Below you'll find more of our best Books under Books tab and if you can't find it please comment the name and subject of the Books and I'll add it from my Online Liborary. Please give me your feedback. thanks in advance

انسان شناسی در قرآن کریم

Personally I love Books. There are those that make you think, make you laugh, motivate and inspire you. Below you'll find more of our best Books under Books tab and if you can't find it please comment the name and subject of the Books and I'll add it from my Online Liborary. Please give me your feedback. thanks in advance

Facebook has more users than the population of the U.S., China, and Brazil combined.

Do you use Facebook? If you don’t, you’re among a number that gets increasingly smaller every day. In fact, 2 billion active users have an account on the social media platform, which is more than the population of the United States, China, and Brazil combined. Facebook’s co-founder and CEO Mark Zuckerberg posted about the milestone, saying, “We’re making progress connecting the world, and now let’s bring the world closer together.”