Top 100 Civil Engineering Interview Questions and its Answers

1) What is a Waffle slabs?

Waffle slabs are a reinforced concrete footing and slab system constructed on ground. They consist of a perimeter footing (edge beam) and a series of narrow internal beams (strip footings) at one meter nominal centers running each way. The whole footing and slab system is constructed on top of the ground.

2) What is a mat foundation?

A mat foundation, according to the Dictionary of Construction, is a continuous foundation with a thick slab that supports a whole structure. The foundation is shallow and poured over reinforcing mats.

3) What is a waffle pod concrete slab?

The Waffle Pod Slab System is a better way of building concrete slabs for new homes, extensions or commercial industrial buildings.

4) How thick is the slab of a house?

Around the edge of the slab, the concrete forms a beam that is perhaps 2 feet deep. The rest of the slab is 4 or 6 inches thick. A 4- or 6-inch layer of gravel lies beneath the slab. A 4-millimeter sheet of plastic lies between the concrete and the gravel to keep moisture out.

5) What is ribbed floor?

Ribbed floors consisting of equally spaced ribs are usually supported directly by columns.They are either one-way spanning systems known as ribbed slab or a two-way ribbed system known as a waffle slab.

6) What is the difference between raft and footing?

Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. ... A mat is necessary when the permissible soil pressure is low or where the columns and walls are so close that person foundation would partly cover or nearly touch each other.

7) What is the raft foundation?

Raft foundations (sometimes known as Mat Foundations) are a large concrete slab which can support a number of columns and walls. The slab is spread out under the entire building or at least a large part of it which lowers the contact pressure compared to the traditionally used strip or trench footings.

8) What is a slab of concrete?

A concrete slab is a common structural element of modern buildings. Horizontal slabs of steel reinforced concrete, typically between 4 and 20 inches (100 and 500 millimeters) thick, are most often used to construct floors and ceilings, while thinner slabs are also used for exterior paving.

9) What is meant by suspended slab?

Suspended slabs are above-ground level slabs which are not directly in contact with the earth. They are commonly used to create floors for the upper storeys of houses, but can also be sat on top of pre-constructed walls to form a ground floor.

10) How thick is a concrete floor?

A concrete floor should be about 4 inches thick if it is in a residential home or building. For a building supporting heavy loads, 5 to 6 inches is the recommended thickness. A good quality concrete floor will have even thickness throughout.

11) How thick is the foundation of a house?

Poured concrete foundation walls that are less than 8 feet tall and have soil outside that is 6 or 7 feet deep against the wall can often be 8 inches thick and function quite well. As soon as you go higher or have greater depths of soil pushing against the wall, you need to increase the thickness to 10 inches.

12) What is a flat slab?

A flat slab is a two-way reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete columns. For more detailed definition: Flat Slab Floor System : Definition & Description.

13) What is a flat plate slab?

The flat plate is a two-way reinforced concrete framing system utilizing a slab of uniform thickness, the simplest of structural shapes. The flat slab is a two-way reinforced structural system that includes either drop panels or column capitals at columns to resist heavier loads and thus permit longer spans.

14) What is footing in civil engineering?

The term footing is used in conjunction with shallow foundations commonly. A footing is a foundation unit constructed in brick work, masonry or concrete under the base of a wall or a column for the purpose of distributing the load over a large area.

15) What is a concrete raft slab?

A raft slab is reinforced concrete slab that is strengthened with integral concrete beams in both directions. Usually used as the foundation for new houses and extensions, raft slabs in Australia are designed to comply with Australian standard AS 2870.

16) What is a foundation pad?

Pad foundations are generally shallow foundations, but can be deep depending on the ground conditions. They are a form of spread foundation formed by rectangular, square, or sometimes circular concrete 'pads' that support localized single-point loads such as structural columns, groups of columns or framed structures.

17) What is a slab foundation?

Slab-on-grade foundation. As the name suggests, a slab is a single layer of concrete, several inches thick. The slab is poured thicker at the edges, to form an integral footing; reinforcing rods strengthen the thickened edge. The slab normally rests on a bed of crushed gravel to improve drainage.

18) What is a frost wall?

A frost wall is a type of wall that adds no structural integrity to the building, but acts as an insulator. It is typical to see frost walls placed in basements since most basements are made of nothing more than cement and brick, which does not provide much insulation.

19 What is a concrete mud slab?

mud slab (plural mud slabs) (construction) A layer of concrete, typically 2 to 6 inches thick, poured below the structural slab but above a layer of wet or muddy soil.

20) What is a slab in civil engineering?

Concrete slab, a very common and important structural element, are constructed to provide flat, useful surfaces. It is a horizontal structural component, with top and bottom surfaces parallel or near so. The depth of a concrete slab floor is very small compared to its span.

21) How thick is the concrete in a garage floor?

The form should have a slight slope (a couple of inches per 20 ft) so that water runs away from the area instead of pooling on your garage floor. The slope should be steeper if you have a sink or water heater in the garage. Step 5: Pour and level the concrete. A standard garage floor is typically 4 inches thick.

22) How deep does the foundations need to be?

The projection of the footing on either side of the wall is supposed to be no greater than the depth of the footing. The bottom of the footing should be at least 12" below the finished grade line (surface of the ground). It may need to be deeper. It must be below the frost line.

23) How deep are footers for a house?

As you can see, heavy houses on weak soil need footings 2 feet wide or more. But the lightest buildings on the strongest soil require footings as narrow as 7 or 8 inches. Under an 8-inch-thick wall, that's the same as saying you have no footing.

24) What is a floating concrete slab foundation?

A concrete floating slab is a slab that is not anchored to the ground but instead merely sits on top of it. Floating concrete slabs provide solid foundations for structures as sheds, garages, home additions, and even manufactured homes.

25) What is a suspended floor?

A suspended Floor is a specialist construction made of a solid concrete Floor, a system of sleeper walls and timber joists, upon which sits a supported timber floor.

26) What is meant by one way slab?

1) One way slab is supported by beams in only 2 sides. 2) The ratio of longer span panel (L) to shorter span panel (B) is equal. or greater than 2. Thus, L/B >= 2. 3) Main reinforcement is provided in only one direction for one way slabs.

27) What is a coffer slab?

A coffer (or coffering) in architecture, is a series of sunken panels in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault.

28) What is a continuous footing?

A strip footing is a type of shallow foundation which is provided for the load bearing wall and for economy purpose, in row of columns which are so closely spaced that their spread footing overlap or nearly touch each other. Strip footing is also know as continuous footing.

29) What is a concrete strip footing?

A wall footing or strip footing is a continuous strip of concrete that serves to spread the weight of a load-bearing wall across an area of soil. It is the component of a shallow foundation.

30) What is a stem wall?

Basement Slab. Basics. The foundation is the part of the structure that contacts the earth. ... Recreational home built in the mountains or on the beach are often constructed on pier foundations. There are four popular types of foundations that are used: Basements, crawlspaces, Monolithic slab and stem wall slab.

31) What is meant by punching shear?

Punching shear is a type of failure of reinforced concrete slabs subjected to high localized forces. In flat slab structures this occurs at column support points. The failure is due to shear: Piper's Row Car Park, Wolverhampton, UK, 1997 (built in 1965).

32) What is a hollow core slab?

Diagram of a concrete slab of hollow core construction. Photograph of a concrete plank roof. A hollow core slab, also known as a voided slab, hollow core plank or simply a concrete plank is a precast slab of pre-stressed concrete typically used in the construction of floors in multi-story apartment buildings.

33) What is lift slab construction?

Lift slab construction is a method of constructing concrete buildings by casting the floor or roof slab on top of the previous slab and then raising (jacking) the slab up with hydraulic jacks, so being cheaper and faster as not requiring boxing and supports for casting in situ.

34) What is meant by PT slab?

Construction of post-tension slabs on grade is very similar to using reinforcing steel, except for the tensioning step. Cables are arranged as indicated by the engineer and chaired to run through the center of the slab. For residential construction, tendons at 48 inches on center are common.

35) What is a flat plate of the abdomen?

Flat plate of the abdomen, KUB, plain film of the abdomen. Common Use: To visualize and assess the abdominal organs for obstruction or abnormality related to mass, trauma, bleeding, stones, or congenital anomaly. Area Of Application: Kidneys, ureters, bladder, and abdomen.

36) What is a flat plate collector?

A typical flat-plate collector is a metal box with a glass or plastic cover (called glazing) on top and a dark-colored absorber plate on the bottom. The sides and bottom of the collector are usually insulated to minimize heat loss.

37) What are the foundations of a building?

A foundation (or, more commonly, foundations) is the element of an architectural structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep.

38) What is a foundation in engineering?

A foundation is the lowest part of the building structure. ... It is at the periphery of Civil, Structural and Geotechnical Engineering disciplines and has distinct focus on soil-structure interaction. It is also called as ground sill, which transfers loads to the ground. It is generally broken into two categories.

39) What is meant by footing in construction?

Footings are an important part of foundation construction. They are typically made of concrete with rebar reinforcement that has been poured into an excavated trench. The purpose of footings is to support the foundation and prevent settling.

40) What is a spread foundation?

Spread Footings. Square or rectangular shaped blocks of reinforced concrete that typically support a single column or wall of a building. The allowable bearing pressure on the soil determines the size of the spread footing.

41) What is a waffle slab?

Resembling the food after which they are named, concrete waffle slabs are reinforced concrete floors and roofs that use a square grid of deep sides. This form of construction is used in airports, parking garages, commercial and industrial buildings, bridges, residences and other structures requiring extra stability.

42) What is a mat foundation?

Mat Foundations. A mat foundation looks like it sounds. It is a “mat” of concrete that sits on or just below the ground; in other words, a shallow foundation. You may have heard it referred to as a slab foundation, a common choice among home builders.

43) What is a waffle raft slab?

Waffle raft slab construction is quite different from stiffened raft and footing slab structures. The slab ribs are formed on top of the ground using a grid of polystyrene void forms. These are laid out on a leveled area. The construction is ideally suited to very reactive clay sites.

44) What is the use of pile foundation?

Pile foundation systems[edit] Foundations relying on driven piles often have groups of piles connected by a pile cap (a large concrete block into which the heads of the piles are embedded) to distribute loads which are larger than one pile can bear.

45) What is a slab on grade?

Slab-on-grade or floating slab foundations are a structural engineering practice whereby the concrete slab that is to serve as the foundation for the structure is formed from a mold set into the ground. The concrete is then placed into the mold, leaving no space between the ground and the structure.

46) What is open foundation?

Open Foundation is a tertiary preparation program offered by the University of Newcastle for people who have been out of the education system for some time, and who hope to study in an undergraduate degree program in the future.

47) What is the difference between raft and footing?

Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. ... A mat is necessary when the permissible soil pressure is low or where the columns and walls are so close that person foundation would partly cover or nearly touch each other.

48) What is the use of plinth beam?

You can see here the beam is constructed at ground level. The void between the foundation and plinth level is filled with compacted soil. Brick or stone masonry is usually constructed below the plinth beam. The plinth beam needs to be strong, but need not be made up of reinforced cement concrete (RCC) all the time.

49) How thick is a concrete foundation slab?

Around the edge of the slab, the concrete forms a beam that is perhaps 2 feet deep. The rest of the slab is 4 or 6 inches thick. A 4- or 6-inch layer of gravel lies beneath the slab.

50) What does on a grade mean?

In real estate, above grade means the portion of a home that is above the ground. The term is usually used to describe a room or square footage. For example, 3 bedrooms above grade means 3 bedrooms that are not in a

51) What does monolithic slab mean?

Monolithic slabs are foundation systems constructed as one single concrete pour that consists of a concrete slab with thickened portions of the slab under load bearing walls and all perimeter edges that take the place of footers.

52) What is the meaning of slab on grade?

A slab-on-grade means no basement, no basement walls, just one slab of concrete on which you build your house. They aren't suitable for all building sites, which we will get into later, but for now let's assume you can build on one.

53) What is a slab of concrete?

A concrete slab is common structural element of modern buildings. Horizontal slabs of steel reinforced concrete, typically between 4 and 20 inches (10 and 50 centimeters) thick, are most often used to construct floors and ceilings, while thinner slabs are also used for exterior paving.

54) What is the meaning of suspended slab?

Suspended slabs are above-ground level slabs which are not directly in contact with the earth. They are commonly used to create floors for the upper storeys of houses, but can also be sat on top of pre-constructed walls to form a ground floor.

55) What is span in civil engineering?

Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge. A span can be closed by a solid beam or by a rope. The first kind is used for bridges, the second one for power lines, overhead telecommunication lines, some type of antennas or for aerial tramways.

56) What is the meaning of suspended slab?

Suspended slabs are slabs that are not in direct contact with the ground. They form roofs or floors above ground level. Suspended slabs are grouped into two types: one way slabs which are supported on two sides. two way slabs which are supported on all four sides.

57) What is a beam and column?

If you keep it horizontally it is called a Beam which carries the loads by bending, simply called flexure. If you keep it vertically forms a Column which carries load by undergoing compression. If you keep it in an inclined fashion it is called a Strut which carries horizontal and vertical components of forces.

58) How thick does a concrete slab need to be for a garage?

The form should have a slight slope (a couple of inches per 20 ft) so that water runs away from the area instead of pooling on your garage floor. The slope should be steeper if you have a sink or water heater in the garage. Step 5: Pour and level the concrete. A standard garage floor is typically 4 inches thick.

59) Can you put concrete on concrete?

Yes, you can pour new concrete over top of the old, but here are some things to keep in mind. If your new slab will be larger than the old building, you need to be careful about cracks mirroring through around the perimeter of the old building. I would recommend using some extra rebar in these areas.

60) How thick does a concrete floor need to be?

A concrete floor should be about 4 inches thick if it is in a residential home or building. For a building supporting heavy loads, 5 to 6 inches is the recommended thickness. A good quality concrete floor will have even thickness throughout.

61) What is the raft foundation?

Raft foundations (sometimes known as Mat Foundations) are a large concrete slab which can support a number of columns and walls. The slab is spread out under the entire building or at least a large part of it which lowers the contact pressure compared to the traditionally used strip or trench footings.

62) How deep does a footing need to be for a block wall?

The first step in building a block wall is pouring a concrete footing for the blocks to rest on. The footing has to be below frost line and as level as you can make it. For a foundation wall with 7 courses (rows) of block, the footing was 30 inches below grade, 24 inches wide and 12 inches deep.

63) What is a frost wall?

A frost wall is a type of wall that adds no structural integrity to the building, but acts as an insulator. It is typical to see frost walls placed in basements since most basements are made of nothing more than cement and brick, which does not provide much insulation.

64) What is a floating foundation?

FLOATING FOUNDATION-: A floating foundation is the foundation of a building that does not use footings,The foundation actually does float on the earth and moves as the temperatures compact and expand the soil. It is also known as a slab foundation.

65) What is floating in concrete?

A concrete float is a tool used to finish a concrete surface by making it smooth. Afloat is used after the surface has been made level using a screed. In addition to removing surface imperfections, floating will compact the concrete as preparation for further steps.

66) What is a suspended floor construction?

Suspended Timber Ground Floors consist of the finished timber floorboards being attached to floor joists, which are suspended above the sub-floor of the foundation. These floor joists are raised above the sub-floor on small supporting walls called tassel walls (or sleeper walls).

67) What is a footing in construction?

Footings are an important part of foundation construction. They are typically made of concrete with rebar reinforcement that has been poured into an excavated trench. The purpose of footings is to support the foundation and prevent settling. Footings are especially important in areas with troublesome soils.

68) What is a pile mat?

A pile cap is a thick concrete mat that rests on concrete or timber piles that have been driven into soft or unstable ground to provide a suitable stable foundation. It usually forms part of the foundation of a building, typically a multi-story building, structure or support base for heavy equipment.

69) What is Coffering used for?

A coffer (or coffering) in architecture, is a series of sunken panels. in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault.

70) What is a waffle slab?

Resembling the food after which they are named, concrete waffle slabs are reinforced concrete floors and roofs that use a square grid of deep sides. This form of construction is used in airports, parking garages, commercial and industrial buildings, bridges, residences and other structures requiring extra stability.

71) What is a concrete strip footing?

A wall footing or strip footing is a continuous strip of concrete that serves to spread the weight of a load-bearing wall across an area of soil. It is the component of a shallow foundation.

72) What is a continuous footing?

A strip footing is a type of shallow foundation which is provided for the load bearing wall and for economy purpose, in row of columns which are so closely spaced that their spread footing overlap or nearly touch each other. Strip footing is also know as continuous footing.

73) What is a strip foundation used for?

Deep Strip foundations are the least expensive and are used. when ground conditions are good. A concrete strip, sometimes reinforced with steel mesh, supports the walls. The trench depth is variable but in most cases should be at least 1m with a width of 600mm. The concrete should have a minimum depth of 225 mm.

74) What is the foundation wall?

If typical continuous concrete footings are used, they usually support a foundation wall that acts either as a retaining wall to form a basement or as a frost wall with earth on both sides. Foundation walls can be built of reinforced concrete or masonry, particularly...

75) How deep should the footing be?

The projection of the footing on either side of the wall is supposed to be no greater than the depth of the footing. The bottom of the footing should be at least 12" below the finished grade line (surface of the ground). It may need to be deeper. It must be below the frost line.

76) What is punching shear in flat slabs?

Punching shear is a type of failure of reinforced concrete slabs subjected to high localized forces. In flat slab structures this occurs at column support points. The failure is due to shear.

77) What is two way shear?

However two way shear is punching shear and its effect is two way. It's also called flat slab shear. You can press your Palm with pen to visualize two way shear. Pen tries to punch and hence two way shear is called punching shear.

78) What is hollow core plank?

A hollow core slab, also known as a voided slab, hollow core plank or simply a concrete plank is a precast slab of pre-stressed concrete typically used in the construction of floors in multi-story apartment buildings.

79) What is meant by pre-stressed concrete?

Pre-stressed concrete is a method for overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete. It is often used in commercial and residential construction as a foundation slab.

80) What is slip form construction?

Slip forming, continuous poured, continuously formed, or slipform construction is a construction method in which concrete is poured into a continuously moving form. Slip forming is used for tall structures (such as bridges, towers, buildings, and dams), as well as horizontal structures, such as roadways.

81) What is a tilt up?

Tilt-up, tilt-slab or tilt-wall is a type of building and a construction technique using concrete. Though it is a cost-effective technique with a shorter completion time, poor performance in earthquakes has mandated significant seismic retrofit requirements in older buildings.

82) What is post tensioning of concrete?

Post tensioning is a technique for reinforcing concrete. ... Prestressing simply means that the steel is stressed (pulled or tensioned) before the concrete has to support the service loads. Most precast, prestressed concrete is actually pre-tensioned-the steel is pulled before the concrete is poured.

83) What is the function of a foundation?

Foundation is the lower portion of the building usually located below ground level, which transmits the loads of the super structure to the supporting soil. A foundations therefore that part of the structure which is in direct contact with the ground to which loads are transmitted.

84) What is the combined footing?

It is used when the two column are so close to each other that their individual footings would overlap. A combined footing is also provided when the property line is so close to one column that a spread footing would be eccentrically loaded when kept entirely within the property line.

85) What is a ribbed slab?

They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Normally the ribs and the beams are the same depth.

86) What is a flat slab?

A flat slab is a two-way reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete columns.

87) What is a spread footing?

role in building foundations. in soil mechanics. ... Spread foundations may be either of the spread footing (made with wide bases placed directly beneath the load-bearing beams or walls), mat (consisting of slabs, usually of reinforced concrete, which underlie the entire area of a building),

88) What is a deep foundation?

A deep foundation is a type of foundation which transfers building loads to the earth farther down from the surface than a shallow foundation does, to a subsurface layer or a range of depths. A pile is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site.

89) What is a concrete strip footing?

A wall footing or strip footing is a continuous strip of concrete that serves to spread the weight of a load-bearing wall across an area of soil. It is the component of a shallow foundation.

90) What is a frost wall?

A frost wall is a type of wall that adds no structural integrity to the building, but acts as an insulator. It is typical to see frost walls placed in basements since most basements are made of nothing more than cement and brick, which does not provide much insulation.

91) What is a suspended floor?

A suspended concrete floor is a floor slab where its perimeter is, or at least two of its opposite edges are, supported on walls, beams or columns that carry its self weight and imposed loading. The floor spans between supports and will normally deflect under load to a dimension that is limited by the design used.

92) What is the single span bridge?

A 'span' in engineering parlance means 'the gap between two supports' This bridge is single span: A single span slab is a slab that is supported at either end.

93) What is the slump in concrete?

The concrete slump test measures the consistency of fresh concrete before it sets. It is performed to check the workability of freshly made concrete, and therefore the ease with which concrete flows. It can also be used as an indicator of an improperly mixed batch.

94) What is a caisson pile?

A pile machine in Amsterdam, the Netherlands. Also called caissons, drilled shafts, drilled piers, Cast-in-drilled-hole piles (CIDH piles) or Cast-in-Situ piles, a borehole is drilled into the ground, then concrete (and often some sort of reinforcing) is placed into the borehole to form the pile.

95) What is a suspended floor?

A suspended Floor is a specialist construction made of a solid concrete Floor, a system of sleeper walls and timber joists, upon which sits a supported timber floor.

96) What is a ribbed slab?

They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Normally the ribs and the beams are the same depth.

97) What is a strip foundation?

Strip foundations are used where the soil is of good bearing capacity. The key sizes of a strip foundation for concrete cavity wall construction and timber frame cavity wall construction are similar. ... The depth of a strip foundation must be equal to or greater than the overall width of the wall.

98) What is meant by punching shear?

Punching shear is a type of failure of reinforced concrete slabs subjected to high localized forces. In flat slab structures this occurs at column support points. The failure is due to shear.

99) What is a hollow core slab?

Diagram of a concrete slab of hollow core construction. Photograph of a concrete plank roof. A hollow core slab, also known as a voided slab, hollow core plank or simply a concrete plank is a precast slab of prestressed concrete typically used in the construction of floors in multi-story apartment buildings.

100) What is Slipform paver?

Slipform paving is defined as a process used to consolidate, form into geometric shape and surface finish a PCC mass by pulling the forms continuously through and surrounding the plastic concrete mass.

101) What is meant by shallow foundation?

A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a deep foundation.

102) What is a pier in construction?

Pier, in building construction, vertical load bearing member such as an intermediate support for adjacent ends of two bridge spans. In foundations for large buildings,piers are usually cylindrical concrete shafts, cast in prepared holes, while in bridges they take the form of caissons, which are sunk into position.

103) What is the slump test?

The slump test is a means of assessing the consistency of fresh concrete. It is used, indirectly, as a means of checking that the correct amount of water has been added to the mix. The test is carried out in accordance with BS EN 12350-2,Testing fresh concrete.

104) What is the slump value of concrete?

Very dry mixes; having slump 0 – 25 mm are used in road making, low workability mixes; having slump 10 – 40 mm are used for foundations with light reinforcement,

medium workability mixes; 50 - 90 for normal reinforced concrete placed with vibration, high workability concrete; > 100 mm.

About Author:

I am Thomas Britto here to share my experiences in the civil engineering field to all my readers.Today many students are struggling to buy books at high prices. So I decided to start a blog and share my experience and knowledge with all my readers.

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