Important Civil Engineering Interview Questions and Answers

Important Civil Engineering Interview Questions and Answers...

Before going to the civil engineering interview questions and answers, we must be known what is civil engineering?

This civil engineering interview questions and answers has to be prepared only means for an idea for the civil engineering students and civil engineers of their job interview or placement.

 Q. What is Civil Engineer ?

Civil Engineering is one of the broadest and oldest of the engineering disciplines, extending across many technical specialties. Civil engineers conceive, design, build, supervise, operate, construct and maintain infrastructure projects and systems in the public and private sector, including roads, buildings, airports, tunnels, dams, bridges, and systems for water supply and sewage treatment.

OR,

Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings.

Civil Engineering Interview Questions and Answers..

Q1. What is diversion tunnel in a dam?

Answer – When a dam is to be built, a diversion tunnel is usually bored through solid rock next to the dam site to bypass the dam construction site. The dam is built while the river flows through the diversion tunnel.

Q2. What are the main reasons of a building collapse?

Answer – There are several reasons for building collapse. Passage of time is the main reason. Also, weak foundations, natural calamities like earthquakes, hurricanes, etc., are the major reasons for building collapse. Bombing and destruction are also another major reason.

Q3. Why should pumping be not used in case of concreting works?

Answer – During the pumping operation, the pump exerted pressure must overcome any friction between the pumping pipes and the concrete, also the weight of the concrete and the pressure head when the concrete is placed above the pumps. Since only water is pumpable, all the pressure generated is by the water that is present in the concrete. The major problem due to pumping are segregation effects and bleeding. In order to rectify and reduce these effects, generally, the proportion of the cement is increased in order to increase the cohesion, which leads to the reduction of segregation and bleeding. Also if a proper selection of the aggregate grading can vastly improve the concrete pump ability.

Q4. In the design of bridge arguments what considerations should be made to select the orientation of the wing walls?

Answer – Some of the most common arrangements of wing walls in cases of bridge arguments are as follows:

(a) Wing walls parallel to abutments: This method is considered to take the least amount of time to build and is simple as well. But on the downside, this method is not the most economical. The advantage of this type of design being that they cause the least amount of disturbance to the sloping embankment.

(b) Wing walls at an angle to abutments: This design method is considered to be the most economical in terms of material cost.

(c) Wing walls perpendicular to abutments: The characteristic of this design is it provides an alignment continuous with the bridge decks lending a support to the parapets.

Q5. What is the basic difference in absorption, adsorption, and sorption?

Answer – Absorption refers to the phenomenon where an atom, molecule or ions enter any bulk phase like gas, solid or liquid. Absorption refers to the phenomenon where the energy of a photon is transferred to other entity.
Adsorption is similar to absorption. It refers to the surface rather than a volume. Adsorption takes place when the gas or liquid solute accumulates on the surface of solid. A substance diffuses in liquid or solid to form a solution.

Q6. What are the steps involved in the concreting process, explain?

Answer – The major steps involved in the process of concreting are as follows:

a) Batching
b) Mixing
c) Transporting and placing of concrete
d) Compacting.

(a) 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: (i) volume batching and (ii) weight batching.

In the 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.

(b) 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.

(c) 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.

(d) 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.

Q7. Describe briefly the various methods of concrete curing.

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

(a) Spraying of water: On walls, and columns can be cured by sprinkling water.

(b) The wet covering of surface: can be cured by using the surface with wet gunny bags or straw

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

(d) Steam curing: Prefabricated concrete units, steam can be cured by passing it through the units that are under closed chambers. It allows faster curing process and results in faster recovery.

(e) Application of curing compounds: Compounds having calcium chloride can be applied on curing surface. This keeps the surface wet for a very long time.

Q8. What do you understand by “preset” during the installation process of bridge bearings?

Answer – During the installation of bridge bearings, the size of the upper plates is reduced to save the material costs. This process is known as preset. Generally, the upper bearing plate comprises the following components:

(a) The length of bearing
(b) 2 x irreversible movement.
(c) 2 x reversible movement.

The bearing initially is placed right in the middle point of the upper bearing plate. No directional effects of irreversible movement are considered. But since the irreversible movement usually takes place in one direction only the displaced direction is placed away from the midpoint. In such cases, the length of the upper plate is equal to the length of the length of the bearing + irreversible movement + 2 x reversible movement.

Q9. What reinforcements are used in the process of prestressing?

Answer – The major types of reinforcements used in prestressing are:

(a) 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.

(b)  Equilibrium reinforcements: This type of reinforcements are required where several anchorages exist where the prestressing loads are applied in a sequential manner.

(c) 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 are required.

Q10. What is the different type of slump test indications?

Answer – Slump tests are performed to empirically measure the workability 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:

(i) True Slump
(ii) Shear Slump
(iii) Collapse Slump

(i) True Slump: This type of slump is characterised by the general drop in 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, affecting the durability of the concrete.

(ii) 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, affecting 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.

(iii) 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.

Q11. Under what circumstances should pot bearings be used instead of elastomeric bearings?

Answer – Pot bearings are preferred over elastomeric bearings in situations where there are chances of high vertical loads in combinations of very large angle of rotations. Elastomeric bearings always require a large bearing surface so that a compression is maintained between the contact surfaces in between the piers and the bearings. This is not possible to maintained in high load and rotation environment. Also, the usage of elastomeric bearings leads to the uneven distribution of stress on the piers. This results in some highly induced stresses to be targeted at the piers henceforth damaging them. Due to the above reasons pot bearings are preferred over elastomeric bearings in such cases.

Q12. Why should curing not be done by ponding and polythene sheets?

Answer – The primary purpose of curing is to reduce the heat loss of concrete that is freshly placed to the atmosphere and in order to reduce the temperature gradient across the cross-section of the concrete. Ponding is not preferred for curing as this method of thermal curing is greatly affected by cold winds. In addition to that in ponding large amounts of water is used and has to be disposed of from the construction sites. Polythene sheets are used on the basis that it creates an airtight environment around the concrete surface henceforth reducing the chances of evaporation over fresh concrete surfaces. But the usage of polythene can be a drawback as it can be easily blown away by winds and also the water lost by self-desiccation cannot be replenished.

Q13. What is soil analysis?

Answer – Soil analysis is the testing of soil to determine the nutritional and elemental composition of the soil. It is generally tested for knowing the contents of nitrogen, potassium and phosphorous.

Q14. State the applications of the modulus of elasticity.

Answer – Modulus of elasticity is related to the flexibility of the material. The value of modulus of elasticity is pretty important in the case of a deflection of different materials used in building construction.

Q15. How do you measure concrete? Cubic feet, Cubic yards, Cubic Meter

Answer – Cubic feet, Cubic yards, Cubic Meter

Q16. Which is stronger solid steel rod or hollow steel pipe? 

Answer – On a per pound basis, steel pipe is stronger in bending and is less likely to buckle in axial compression.

Q17. What is the tallest man-made structure in the world? 

Answer – The world’s tallest man-made structure is Burj Dubai which is 828.1 meters tall and 2,717 in feet.

Q18. What is braced excavation all about?

Answer – Excavations are braced to prevent the cave-in of surrounding unstable soil.

Q19. What is the meaning of soil reinforcement? 

Answer – Soil reinforcement is the act of improving soil strength to enable it support or carry more load.

Two common examples are:

i) Mixing a soil amendment such as lime into weak clayey soil and re-comPActing to improve soil-bearing caPAcity (often done under the road base in highway construction)

ii) Installing plastic or composite webbing layers (called geo-grid material) alternating with comPActed soil to produce a stronger sloped soil structure (often done on steep roadway embankments to improve strength and stability)

Q20. What is aggregate? 

Answer – Aggregate is the component of a composite material used to resist compressive stress.

Q21. What is absolute pressure?

Answer – Absolute pressure is simply the addition of the observed gauge pressure plus the value of the local atmospheric pressure.

Q22. What is the force exerted by the Tacoma narrows bridge? 

Answer – The force exerted to the Tacoma narrows bridge was initially the wind resistance. The wind resistance caused the whole bridge to act as a system with forced vibration with damping.

Q23. What are the uses of alloys in daily life and how are alloys made? 

Answer – Alloying is not always done to produce a ‘superior’ material, but to produce materials having the desired requirement in the industry or elsewhere. A classic case is of lead solder (containing lead & tin), in which the melting point of the constituent elements are lowered, not necessarily a desirable property.

Alloying can be carried out using hot press method (a sheet of material is sandwiched with the alloying material), rolling the heated base metal in a drum full of alloying metal powder, using hot spraying, galvanizing (dipping the base in a molten solution of alloying material) etc. Sometimes the alloying material is added in small proportions to the molten base metal (e.g., in the production of different types of steel).What is the

Q24. Which is the world’s largest concrete dam? 

Answer – The Grand Coulee Dam is said to be the largest concrete dam. Currently, the world’s largest concrete dam is the Itaipu Dam, an accomplishment of two neighbouring countries, Brazil and Paraguay in South America.

Though it is not finished yet, the Three Gorges Dam on the Yangtze River in China will take over as the largest upon its completion, which is slated for 2009.What are the main reasons of

Q25. What are the main reasons of a building collapse?

Answer – There are several reasons for building collapse. Passage of time is the main reason. Also, weak foundations, natural calamities like earthquakes, hurricanes, etc., are the major reasons for building collapse. Bombing and destruction are also another major reason.

Q26. Describe briefly the advantages and disadvantages of using plastic and timber fenders?

Answer – The advantages and disadvantages of using plastic fenders are as follows:

Plastic fenders are low in strength with a relatively high resistance to abrasion. Plastic fenders are resistant to chemical and biological attacks. Plastic fenders have moderate energy absorption capacity. The berthing reactions are also comparatively moderate and depend on the point of contact. Also since they are made from recycled material they are environmentally friendly.

The advantages and disadvantages of using timber fenders are:

Different timber fenders are low in strength and are very susceptible to marine borer attacks and rotting. The energy absorption capacity is very low. Also generally the contact pressure between the vessels and the fender are high.timber fenders are low in strength and are very susceptible to marine borer attacks and rotting. The energy absorption capacity is very low. Also generally the contact pressure between the vessels and the fender are high.

Q27. How are the freeway bridges built?

Answer – The traffic that is likely to go over the bridge at a time is estimated and the cement, rocked with rebar stanchions is placed over the freeway to build a bridge. The off-ramp from a freeway to the bridge and on-ramp from the bridge to the freeway are constructed. Cement slabs are used to build a platform.

Q28. Why are steel plates inserted inside bearings in elastomeric bearings?

Answer – In order to make an elastomeric bearing act/ function as a soft spring, it should be made to allow it to bulge laterally and also the stiffness compression can be increased by simply increasing the limiting amount of the lateral bulging. In many cases in order to increase the compression stiffness of the bearing the usage of metal plates is made. Once steel plates are included in the bearings the freedom of the bulge is restricted dramatically, also the deflection of the bearing is reduced as compared to a bearing without the presence of steel plates. The tensile stresses of the bearings are induced into the steel plates. But the presence of the metal plates does not affect the shear stiffness of the bearings.

Q29. What is the ratio of Grades M5, M7.5, M10, M15, M20, M25, M30, M35, M40?

Answer – 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 – Design Mix Followed

Q30. What are the types of reinforcement steel used in concrete?

Answer – Generally, there are two types of steel bars (“Sariya” in Hindi) available in the market.

(i) Mild steel bars
(ii) Deformed steel bars

(i) Mild steel bars (as per IS: 432, part-I -1982)

Mild steel bars are used for tensile stress of RCC (Reinforced cement concrete) slab beams etc. in reinforced cement concrete work. These steel bars are plain in surface and are round sections of diameter from 6 to 50 mm. These rods are manufactured in long lengths and can be cut quickly and be bent easily without damage.

(ii) Deformed steel bars (as per IS: 1786-1985)

As deformed bars are rods of steels provided with lugs, ribs or deformation on the surface of the bar, these bars minimize slippage in concrete and increases the bond between the two materials. Deformed bars have more tensile stresses than that of mild steel plain bars. These bars can be used without end hooks. The deformation should be spaced along the bar at substantially uniform distances. To limit cracks that may develop in reinforced concrete around mild steel bars due to stretching of bars and some

To limit cracks that may develop in reinforced concrete around mild steel bars due to stretching of bars and some loss of bond under load it is common to use deformed bars that have projecting ribs or are twisted to improve the bond with the concrete. These bars are produced in sections from 6 mm to 50 mm dia.

In addition, the strength of bonds of deformed bars calculated should be 40 to 80 % higher than that of plain round bars of same nominal size. And it has more tensile stress than that of plain round bars of same nominal size.Cold twisted deformed (Ribbed or Tor Steel Bars) bars are recommended as best quality steel bars for construction work by structural Engineer.

old twisted deformed (Ribbed or Tor Steel Bars) bars are recommended as best quality steel bars for construction work by structural Engineer.