Most Important Interview Questions & Answers for Civil Engineers | Must Read Before an Interview

Top Most Important Questions For Interview Preparation For Civil Engineers

Question 1. What are the different types of foundation?

Three main types of foundation are

• Basement: In this a basement is prepared first on top of it building is constructed
• Crawl space: A crawl space is a raised foundation, it is built above the ground, just allowing enough space to crawl underneath
• Slab: In this foundation, concrete is directly poured into the pit made in the ground.

Question 2. Explain what is Hybrid Foundation?

Hybrid Foundation is usually used for high rise building, it contains both soil supported mat and piles. This type of foundation is helpful in reducing the amount of the settlement.

Question 3. What Are The Steps Involved In The Concreting Process, Explain?

1. Batching: The process of measurement of the different materials for the making of concrete is known as batching. batching is usually done in two ways: volume batching and weight batching. In case of volume batching the measurement is done in the form of volume whereas in the case of weight batching it is done by the weight.

Mixing: In order to create good concrete the mixing of the materials should be first done in dry condition and after it wet condition. The two general methods of mixing are: hand mixing and machine mixing.

Transportation and placing of concrete: Once the concrete mixture is created it must be transported to its final location. The concrete is placed on form works and should always be dropped on its final location as closely as possible.

Compaction of concrete: When concrete is placed it can have air bubbles entrapped in it which can lead to the reduction of the strength by 30%. In order to reduce the air bubbles the process of compaction is performed. Compaction is generally performed in two ways: by hand or by the use of vibrators.

Question 4. Describe Briefly The Various Methods Of Concrete Curing?

Curing is the process of maintaining the moisture and temperature conditions for freshly deployed concrete. This is done for small duration of time to allow the hardening of concrete.The methods that are involved in saving the shrinkage of the concrete includes:

Spraying of water: on walls, and columns can be cured by sprinkling water. 

Wet covering of surface: can be cured by using the surface with wet gunny bags or straw

Ponding: the horizontal surfaces including the slab and floors can be cured by stagnating the water.

Steam curing: of pre-fabricated concrete units steam can be cured by passing it over the units that are under closed chambers. It allows faster curing process and results in faster recovery. Application of curing compounds: compounds having calcium chloride can be applied on curing surface. This keeps the surface wet for a very long time.

Question 5. List out some of the software used in the construction sector to estimate cost and monitoring expenses?

• Tally System
• Sage
• Maxwell System
• Premier construction software
• eTakeoff
• Construction partner, etc.

Question 6. What are the responsibilities of a construction manager?

The responsibilities of a construction manager are

• Cost Estimates
• Pre-purchase of selected materials
• Selection of bidders for bidding phase
• Analysis of proposals
• Construction contract negotiations
• Construction Scheduling and Monitoring
• Cost control of construction
• Construction supervision

Question 7. List out the potential risk factors for workers on the construction site?

Potential risk factors for worker on the construction site

• Falls from heights
• Scaffold and Trench collapse
• Electric shock and arc blast
• Repetitive motion injuries
• Not using personal protective equipment correctly

Question 8. What Reinforcements Are Used In The Process Of Prestressing?

The major types of reinforcements used in prestressing are:

  • Spalling Reinforcement: The spalling stresses leads to stress behind the loaded area of the anchor blocks. This results in the breaking off of the surface concrete. The most likely causes of such types of stresses are Poisson`s effects strain interoperability or by the stress trajectory shapes.
  • Equilibrium reinforcements: This type of reinforcements are required where several anchorages exist where the prestressing loads are applied in a sequential manner.
  • Bursting Reinforcements: These kinds of stresses occur in cases where the stress trajectories are concave towards the line of action of load. In order to reduce such stresses reinforcements in the form of bursting is required.

Question 9. What is the ideal size of the living room ranges from small to large size?

• Very small size living room= 7x10ft ( for two seater sofas on one side of the room)
• Small living room= 10x13ft ( for two 2 seater sofa)
• Medium living room= 12×18 (for 3 Seater sofa)
• Large living room= 15×20 ( for 4 seater or 5 seater sofa)

Question 10. What Are The Different Type Of Slump Test Indications?

Slump tests are performed to empirically measure the work ability of fresh concrete. It is used to measure the consistency of the concrete. In general there are three different types of slumps that occur in slump tests. They are as follows:

True Slump: This type of slump is characterized by the general drop of the concrete mass evenly without visible signs of deterioration or disintegration. 

Shear Slump: It indicates that the concrete mix is deficient in cohesion. This type of slump leads to segregation and bleeding. Henceforth in the long run effecting the durability of the concrete. 

Collapse Slump: This type of slump is indicates that the mix of concrete is simply too wet. The mix is considered to be harsh and lean.

Question 11. Explain what is the difference between built area and super built up area?

• Built up area: It includes your carpet area plus area covered by walls, pillars and ducts. It is usually 10% more from the carpet area
• Super built up area: It includes your built up area plus the area that you use as building amenities like passage to lift, stairs and lifts, gym, club, etc.

 Question 12. List out the types of roofs?

• Half hipped roof
• Dutch gable roof
• Skillion roof
• Gambrel roof
• Gull wind roof
• Mansard roof
• Bell cast roof
• Sawtooth roof
• Monitor roof, etc.

Question 13. Explain what are the problems one might face while having a Cantilever balcony?

Cantilever balcony are usually unsupported and extend outwards, so the problem with Cantilever balconies are

• Excess deflection or bounce
• Weakness of the deck structure
• Rot and water damage to the interior of the house
• Unevenness inside the house
• Can’t use the balcony for gardening or other purposes as it is not designed to lift excess amount of weight

Question 14. For what building Built-on balconies are preferable? What are the advantages?

Built on balconies are mainly designed for retrofitting older buildings. This free standing balcony is supported in front of the facade on four columns. They are backed to the wall with brackets.

The advantage of built-on balconies are

• Old balconies can be dismantled, and the new ones can be erected immediately in front of the faced without disturbing the inner structure of the building
• The work takes place outside of the house, so there is no interference to the interior of the building

 Question 15. How to build the floor to ceiling bookcase?

To build a floor to ceiling bookcase

• First measure the distance between the floor and ceiling
• Cut two boards of the length of that distance
• Cut two boards with the width you require
• Attach top and bottom boards to the side with 2 inch nails. Keep a gap about one or two inches between each nail
• Attach top and bottom boards to the side boards with 2 inch nail. This will create a frame of your bookcase. Add the shelves to the bookcase the way you want and then paint it.

Question 16. What should be the standard roof height like to be?

For inhabited building, standard height for roof should be one or two storeys tall. If you don’t need to make roof taller and yet you want make it look bigger from outside use a mansard roof containing multiple floors. The roof of the room can be adjusted by changing its pitch or by adding a parapet.

Question 17. Which are the top apps for you civil engineeer?

Some of the best apps

• Evernote
• Dropbox
• Instagram
• Sketchbook
• Photoshop Express
• Flipboard
• Magic Plan
• Houzz
• AutoCAD 

Question 18. Explain how you can use different dimension tools in CAD? What are the different dimensions available?

If you are using CAD and want to use dimension tools, then go to CAD>Dimensions and you can have access to a wide range of dimensions like

• Manual dimensions
• Interior dimensions
• Auto exterior dimensions
• Auto interior dimensions
• End to end dimensions
• Point to point dimensions
• Angular dimensions
• Display temporary dimensions
• Moving objects using dimensions

Question 19. Explain how you can turn off the display for dimension in CAD?

The display of your dimensions can be turned off in CAD for that you have to go under Floor Plan View and follow the following steps

• In floor plan active, select Tools – Display Options
• Scroll down to the dimensions- Automatic and Dimensions- Manual layers and remove the checkmarks from the Disp column
• When you click OK, the display of the dimensions in your plan will be turned off.

Question 20. What is the Unit Weight of concrete?

  The unit weight of concrete depends on the type of aggregates and amount of voids. As per IS : 456-200 Unit weight of PCC is 24KN/m3 and RCC is 25KN/m3

Question 21. What is the unit weight of Steel?
The unit weight of Steel is 78.5KN/m3

Question22. What are the Nominal Concrete Mix proportions for different grades:
  Important: M20-1:1.5:3, M7.5- 1:4:8,
        Less imp: M5- 1:5:10 , M25- 1:1:2, M30-1:1:3 (Cement:Sand:aggregate)

Question23. What is ductility?

 Ductility is the Ability to deform under tensile stress.

Question 24. How to find the weight of steel bar used in reinforcement?
Weight of Bar in kg/m = Dsquare/162.2   D- Dia of bar in mm

Question 25. What’s the difference between one-way slab and two-way slab?
 One way slab: Ratio of Longer Span / Shorter span > 2
       Two way slab: Ratio of Longer span/ shorter span <= 2

Question26. What is flat slab?

 The slab which is supported on columns (Flab slab don’t have beams)

Question 27. What do you mean by One storeyed, Two storeyed building?
 The building which has two floors is called two storeyed building.

Question 28. What’s the height of each floor?

Question 29. What’s the length of rise and tread in Stair case?
   Rise – 150mm to 200mm, Tread – 250mm to 300mm

Question 30. What’s the slope of Staircase?

   As per IS 456, the slope or pitch of stair should be between 25 degrees to 40 degrees.

Question 31. What do you mean by the moment of inertia?

  A quantity expressing a body’s tendency to resist angular acceleration, which is the sum of the products of the mass of each particle in the body with the square of its distance from the axis of rotation.

Question 32. What is a crank length in the slab?

 The crank length in Slab is 0.42 D. Where D is Depth of Slab- Top cover – Bottom Cover. 

Question 33. What are the types of a slump?
True Slump: The concrete mass after the test when slumps evenly all around without disintegration is called the true slump.
Shear Slump: When one-half of the concrete mass slide down the other is called the shear slump. This type of slump is obtained in a lean concrete mix.
Collapse Slump: When the sample is collapsed due to adding excessive water, it is known as collapse slump.
Zero Slump:  For very stiff or dry mixes it does not show any changes of the slump after removing the slump cone.

Question 34. What is grouting?

Grout is a fluid form of concrete which is used to fill the voids.

Question 35. What is allowable moisture content in Fine aggregate for the concrete mix?
We won’t use the aggregate if its moisture content is more than 5%.

Question 36. What do you mean by segregation?
Segregation is a separation of cement, sand from aggregate. This is caused due to Water cement ratio and  when concrete is poured about more than 1.5m

Question 37. What is Seepage?

   Slow percolation of water through soil is called Seepage.

Question 38. What is the Compressive Strength of brick?
 Second class brick-70kg/cm2
          First class brick-105kg/cm2
          Fire brick-125kg/cm2

Question 39. How do you check the quality of cement on the site?

   1. Date of Mfg: Cement strength decreases with its age.
         2. Color: Colour should be grey with light greenish shade and it should be uniform. Color gives an indication of excess lime or clay.
         3. Float test: A good cement won’t float if you throw a cement in water.
         4. When you put your hand in cement bag you should feel cool.

Question 40. What is Initial & final setting time of concrete?
 Intial Setting time : 30mins, Final setting time : 10hrs

Question 41. What is durability?
Ability to withstand under pressure is called Durability.

Question 42. What are the concrete tests?
Slump test, Compressive strength test, water permeability test, Water absorption test 

Question 43. What is bleeding in concrete?
Bleeding is one form of segregation, where water comes out to the surface of the concrete,   being lowest specific gravity among all the ingredients of concrete.

Question 44. What is the name of the machine to get compression test?
Universal testing machine (UTM)

Question 45. Describe civil engineering in simple words?

Civil Engineering is the second oldest form of engineering in the world after military engineering.

It is simply defined as an expertise in the process of designing, constructing & maintaining various systems, including public infrastructure, buildings, houses & much more.

Question 46. Which is the tallest man-made structure in the world?

World’s tallest man-made structure is the Burj Dubai which stands at 800 meters tall.

Question 47. According to you, what is that one important quality that a civil engineer should possess?

A civil engineer should have a bunch of important qualities to ensure a strong career path, however, according to me the most important quality which a civil engineer should possess is strong critical thinking & sound technical knowledge.

Question 48. Name the critical elements for a landfill?

There are 4 major landfill elements: Bottom Liner, Collection System, Cover & Natural hydrogeological settings.

Question 49. Discuss different types of building foundations?

While laying a foundation for any construction, three types of foundation patterns are mostly used.

Basement pattern: Wherein the basement of the building is prepared initially & then the rest of the storeys are constructed on top of the basement.

Crawl space pattern: Wherein a raised foundation is constructed first, this foundation is built above the ground, then the rest of the building is made on top.

Slab:This is the simplest way of construction wherein concrete is directly poured in the pit which is made in the ground.

Question 50. What do you understand by segregation?

Segregation is defined as a process of filtering cement & sand separately from the concrete mixture. In other words, segregation is caused due to vibration between materials forming a concrete.

One material being high in weight & one being less tend to be uneven while in a liquid state. The heavier material gets settled at the bottom of the concrete & lighter material moves on top.

Question 51. Explain the cavitation process in pipes & drains?

Usually due to the air bubble formation within the fluids usually because of low-pressure conditions get even lower than the saturation pressure is defined as the cavitation process. This creates a potentially damaging situation to the durability of pipes.

Question 52. What do you understand by soil analysis?

Soil analysis is defined as a process of soil testing to determine nutrients & elements which are embedded within that particular soil sample.

Question 54. What do you mean by concrete curing? What are the methods used for concrete curing?

Concrete curing is the process of maintaining the right temperature & apt moisture level for the recently placed concrete. This process is done to the wet concrete to ensure its drying process takes less time & maximizes concrete strength.

Some of the common methods used in concrete curing are water sprays, ponding, curing compounds, steam curation.

Question 55. What do you understand by slump tests?

Slump Tests are usually done to measure the consistency of the fresh concrete after it’s placed. It also measures the workability of fresh concrete.

Question 56. What is the software used in civil engineering?

AutoCAD and 3D Max are the most popular software used in Civil Engineering. These are helpful in making various high-tech presentations, reports, billing purposes. All the designs, modeling, design, architectural drawing, Auto-desk 2D and 3D designs can be successfully made with the help of this two software.

Question 57. How do you calculate the unit weight of concrete?

To find the weight of the concrete, multiply the length, height, and width of the area where the concrete is to be filled. Then you will get the volume of the place or the volume of the concrete to be used. To get the weight of the concrete in pounds, multiply the volume which we have got in cubic feet by 143.38 pounds/feet^3.

Question 58. What is the crank length in the slab?

Minimum length of a crank is 300 mm.

The formula of Crank length = (d1+d2+5) *10mm where d1 is the diameter of smaller bar and d2 is the diameter of the largest bar.

Also, the slope of the crank is 1:10 (one of the common civil engineering interview questions.)

Question 59. What is the strength of cement?

The cement’s strength is tested on hardened Cement-Sand mortar’s cubes, and these are prepared out of the cement which has a strength of 53MPa. It is derived from 53 Grade OPC Cement giving 28-days of compressive strength of the cement. It is one of the most common civil engineering interview questions.

Question 60. How is the strength of cement measured?

The measurement is done after the curing process has taken place for 7 days or 28 days. The load should be applied slowly at the rate of 140 kg/cm2 per minute until the Specimens fails. We get the compressive strength of the concrete or the cement at the load failure divided by the specimen’s area.

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