civil engineering interview questions for freshers experienced :-
1. Define What is Civil Engineering ?
Civil engineering is arguably the oldest engineering discipline. It deals with the designed setting and may be dated to the primary time somebody placed a roof over his or her head or set a stalk across a stream to form it easier to urge across.
The designed setting encompasses abundant of what defines fashionable civilization. Buildings and bridges area unit usually the primary constructions that come back to mind, as they’re the foremost conspicuous creations of structural engineering, one in every of civil engineering’s major sub-disciplines. Roads, railroads, subway systems, and airports area unit designed by transportation engineers, another class of engineering. so there area unit the less visible creations of civil engineers. each time you open a water tap, you expect water to return out, doltishly that civil engineers created it attainable. the big apple town has one in every of the world’s most spectacular water system systems, receiving billions of gallons of high-quality water from the mountain chain over 100 miles away. Similarly, not many of us appear to fret regarding what happens to the water once it’s served its functions. The recent engineering discipline of sanitary engineering has evolved into fashionable environmental engineering of such significance that almost all educational departments have modified their names to civil and environmental engineering.
These few examples illustrate that civil engineers do lots quite style buildings and bridges. they’ll be found within the region business, coming up with jetliners and house stations; within the automotive business, perfecting the load-carrying capability of a chassis and rising the crash worthiness of bumpers and doors; and that they is found within the ship building business, the ability business, and lots of different industries where made facilities area unit concerned. and that they arrange and supervise the development of those facilities as construction managers.
2. What are the causes of building collapse?
The passage of time is one reason. Buildings also collapse due to weak foundations. Earthquakes, hurricanes and other natural disasters can also damage the structure of the buildings and cause it to collapse. Bombings or demolition of buildings is also other reasons.
3. What are the applications of modulus of elasticity?
As the term implies, “Modulus of Elasticity” relates to the elasticity or “flexibility” of a material. The value of modulus of elasticity is very much significant relating to deflection of certain materials used in the construction industry. Take for example the general E value of mild carbon steel is about 200 Gpa compared to about 70 Gpa for aluminum. This simply translate that aluminum is 3 times flexible than steel.
4. Define What is the difference between routing maintenance and major maintenance in school facilities?
- The routine maintenance is the minor and consistent repairs that are engaged in the school premises. Examples could include painting, replacement of fixtures, louver blades, furniture repairs, and patching cracks in the school buildings.
- The major maintenance could also be a total rehabilitation of the school, either school buildings or any other project within the school community. It could be total restructuring of the lighting system in the school or sanitary system.
5. How are freeway bridges built?
After calculating the anticipated traffic for the bridge, cement/reinforced- with- rebar stanchions are spaced over the freeway to accommodate the bridge. An ‘off-ramp’ from the freeway to the bridge is constructed, as is an ‘on-ramp’ to the subsequent road. Cement/rebar slabs are built and lifted with cranes to form the platform, and voila! Drive carefully.
Although the bridge deck/roadway is almost always a concrete slab, the structure that holds up the bridge deck can be reinforced concrete, structural steel, or a combination of steel and concrete.
6. What is the difference between absorption & adsorption and sorption?
- Absorption generally refers to two phenomena, which are largely unrelated. In one case, it refers to when atoms, molecules, or ions enter some bulk phase – gas, liquid or solid material. For instance, a sponge absorbs water when it is dry.
- Absorption also refers to the process by which the energy of a photon is taken up by another entity, for example, by an atom whose valence electrons make transition between two electronic energy levels. The photon is destroyed in the process. The absorbed energy may be re-emitted as radiant energy or transformed into heat energy. The absorption of light during wave propagation is often called attenuation. The tools of spectroscopy in chemistry are based on the absorption of photons by atoms and molecules.
- Adsorption is similar, but refers to a surface rather than a volume: adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorb-ate). It is different from absorption, in which a substance diffuses into a liquid or solid to form a solution.
7. How do you measure concrete?
Cubic feet, Cubic yards, Cubic Meter
8. Define What is the tallest man made structure in the world?
The tallest man made structure is the KVLY-TV mast which is 2063 feet tall. The worlds tallest man made structure is Burj Dubai which is 800 meter tall.
9. Define What are the uses of alloys in daily life and how are alloys made?
- Alloying is not always done to produce a ‘superior’ material, but to produce materials having a 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 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 production of different types of steel).
10. What is the worlds largest concrete dam?
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 neighboring countries, Brazil and paraguay in South America.
Though it is not finished yet, the Three Gorges (or Sandapong) Dam on the Yangtze River in China will take over as the largest upon its completion, which is slated for 2009.
11. What is braced excavation all about?
Excavations are braced to prevent the cave-in of surrounding unstable soil.
12. What is the meaning of soil reinforcement?
Soil reinforcement is the act of improving soil strength to enable it support or carry more load.
Two common examples are:
- 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)
- 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)
13. Define What is aggregate?
Aggregate is the component of a composite material used to resist compressive stress.
14. What year was the keystone power plant in Indiana County constructed?
1967 began commercial operation on unit 1.
15. Define What is the force exerted by the Tacoma narrows bridge?
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.
16. How do you calculate the power of a centrifugal pump?
The input power, that is, the power required to operate the pump should be stated in Hp (horsepower) on the pump’s nameplate. It can also be calculated by the 3-phase power equation:
P(in Hp) = VI(1.7c) = Rated Voltage x Rated Current x 1.73/ %Efficiency
If this is a consumer grade pump that operates on 120Vac, then the equation becomes P = VI, simply multiply the operating voltage, 120 x current (which is the number followed by the letter “A”.
The output power, which really is not technically power, but rated in Gpm (gallons per minute), or capacity should also be on the nameplate. If you have the make, model, and (not necessarily needed) the serial number (also on the nameplate) you could call the manufacturer’s customer service dept. As an application engineer, I have contacted countless manufacturers’, and service dept’s for assistance. It is now big deal to them, they will be happy to answer your questions.
17. Why nautical mile is different from statute mile?
One nautical mile is defined by one latitude minute of arc (there are 60 such minutes to a degree). This equals 1852 meters, and roughly (but coincidentally) 2000 yards or 6000 feet. (Edit: actually, a standard nautical mile is 6076 feet, 6000 feet and 2000 yards are commonly used approximations, but produce an error of about 1%).
The statute mile had a little fuzzier definition to start with, as one mile was the same as 1000 roman paces/steps. The definition has since changed, but one statute mile equals about 1609 meters.
18. Define What is rigging?
In sailing, the ropes used to move the sails around so the boat will move in the right direction when the wind blows.
19. What is absolute pressure?
Absolute pressure is simply the addition of the observed gage pressure plus the value of the local atmospheric pressure.
20. How do we calculate absolute pressure?
Absolute is equal to gauge pressure plus atmospheric.
21. What is Gravity flow?
Gravity flow is fluid flowing due to the forces of gravity alone and not to an applied pressure head. In the Bernoulli equation, the pressure term is omitted, and the height and velocity terms are the only ones included.
22. What is horizon or horizontal mining?
- Horizon or horizontal mining can be applied to extraction of material from seams of any stratified mineral such as limestone or ironstone, but it is more usually associated with coal – particularly where there are several seams that are inclined or folded and/or faulted.
- Horizon mining involves long level roadways (horizons) being driven from the shafts to the extremity of the area to be mined.
- The levels of the horizons are chosen to intersect the maximum number of seams the maximum number of times. As the seams are intersected, headings will be driven into the seam so that the desired material may be extracted. This method of mining requires a thorough understanding of the geological structure of the area to be mined so that the level of the horizons can be chosen for optimum results.
- This method of mining is popular in modern coalmines with seams worked from several horizons. The considerable capital outlay of driving horizons before production can begin is recouped by the advantage of having long straight level roadways of generous dimensions unaffected by the crushing effect of nearby extraction of the mineral.
23. What is the difference between engineering stress and true stress?
In biology, Stress is something that disrupts homeostasis of an organism. In engineering, Stress is an external force that pushes, pulls, twists, or otherwise puts force on something.
Engineering stress assumes that the area a force is acting upon remains constant, true stress takes into account the reduction in area caused by the force.
24. Define What is a kip?
1 kip = 1000 lbs
25. What are some structures that may be subjected to fatigue?
Bridges, hydraulic presses, burners trains
26. Will going from a 3-tap to 6-tap increase water pressure?
No, the pressure will be the same, you will get more volume only if your pumps can handle the GPM, to increase pressure you may need a booster pump or a single pump that is rated for your needs.
27. Why does the pressure increase under soil?
Soil pressure increases with depth due to the overburden or self-weight of the soil and due to loads imposed upon the soil.
For example, the pressure variation below the depth of soil is linear and the relation is given by pressure = unit wt * depth. As depth increases, there will be a linear increase in the soil pressure.
28. Define What is the distance between railway tracks?
4 feet, 8 1/2 inches
29. How high should the water tank be to provide a 60 PSI at base of this water tower?
2.31ft of water= 1 PSI
30. Define What are the reasons for geotechnical site investigations in Uganda?
- To know the soil properties, in so doing be in position to determine whether the particular site is suitable for the purpose intended
- To know the history of the site
- To know what remedies need to be put in place before construction can start
- Based on the soil properties, that can be determined on site and in the lab, design the appropriate foundation for the structure.
31. What do you mean by honeycomb in concrete?
Some people call it an air pocket in the concrete or a void.
32. What is the purpose of the gap in the road on this bridge?
Purpose of the gap in the road is to allow the road to expand and contract with temperature changes without causing damage or deformation to the road.
33. Define What is the tensile strength of wood?
The tensile strength of a material is the value at which the material fails when subjected to a tensile force. (Tensile means a force pulling the wood fibers lengthwise, as opposed to a compression force.) There are a lot of different types and load cases for wood, so there is not one answer to this question. For example, wood used outside will fail at a lower load than wood inside. Wood is also an isotropic, i.e. it has different strength in different directions.
Example values of tensile strength vary anywhere from 175 pounds per square inch for Utility Grade pine to 1400 PSI for Dense Select Structural grade Douglas Fir. A good reference for material strength data for most species and grades of commercially available wood can be found in the American Institute of Timber Construction handbook.
34. How many Lbs are there in a yard?
A pound (Lb) is a unit of measurement for weight while a yard is a unit of measurement for distance.
If you are referring to common measurements used on a construction site, a “yard” is a common abbreviation for a “cubic yard”, which is a unit of measurement of volume. (A cubic yard equals 27 cubic feet.)
Since dirt weighs about 110 pounds per cubic feet, a cubic yard of dirt weighs about 2970 Lbs. Since concrete is heavier (150 PCF), a cubic yard of concrete weighs about 4050 Lbs.
35. Define What is a projection line?
Projection line is the way, in which the earth is shown on a flat piece of paper.
36. What are moment of inertia and its importance in civil engineering?
The moment of inertia measures the opposition any kind of body will have against a certain momentum (along that same axis) trying to rotate that body.
37. Define What is the origin of name Railway Sleepers?
When sleepers were added below the railway, lines the trains ran more smoothly and people fell asleep on their journeys.
38. What is BMC stands for in BMC Software?
BMC Software founders Scott Boulette, John Moores, and Dan Cloer began a contract programming partnership that operated in and around Houston, Texas.
39. Does brick grows bigger every year.
Usually bricks do not grow, but since stuff gets all over, it looks like it grows.
40. How did street originate in the plumbing term street ell?
A “street ell” may have gotten its name because it describes a 90° fitting particularly useful in tight, street ditches. When installing water pipes under a street, or from a water service, again under the street, into a home or business, this street ell allows one to change pipe direction with one less fitting, and in less space, than with a standard ell.
41. What is the absolute pressure scale?
Absolute pressure is calculated from a vacuum (0 PSI) and atmospheric pressure is14.7PSIa or 14.7 PSI above a vacuum 1PSI on a tire pressure gauge is called 1PSIg = 15.7PSIa 10PSIg=24.7PSIa 100PSIg=114.7PSIa etc.
42. What is the difference between QA and QC?
Many people and organizations are confused about the difference between quality assurance (QA), quality control (QC), and testing. They are closely related, but they are different concepts. Since all three are necessary to manage the risks of developing and maintaining software, it is important for software managers to understand the differences. They are defined below:
- Quality Assurance: A set of activities designed to ensure that the development and/or maintenance process is adequate to ensure a system will meet its objectives.
- Quality Control: A set of activities designed to evaluate a developed work product.
- Testing is the process of executing a system with the intent of finding defects. (Note that the “process of executing a system” includes test planning prior to the execution of the test cases.)
43. How did the Romans get water up hills using aqua ducts?
Technically, the Romans were not able to get water to move uphill in a general sense. All aqueducts move water from an elevated source (spring-fed streams in the mountains) to end-users at a lower elevation. The water flows almost entirely downhill from the source to the end user. If the water needed to cross a valley, the Romans would build an arched structure with an elevated channel to cross the valley, but even this channel would have a vary slight downhill gradient that allowed water to flow towards the end user. If a large hill was in their way, the Romans would either divert the channel around the hill, dig a trench through the hill, or dig a tunnel through the hill, all while maintaining a fairly constant, slight downhill gradient towards the end user.
The only exception to the rule of a generally constant downhill slope to the water channel is that specific tunnel segments, the Romans could build the tunnel as an inverted siphon (mentioned above) to cross a depression or valley and raise the water level on the downhill side almost to the level of the uphill side. To do this requires a well-sealed tunnel strong enough to withstand the increased water pressure within the siphon. Note, however, that except for gaining a little bit of elevation if you slow down fast-moving water, you normally cannot get water to flow out of the outlet at a higher elevation than the inlet. So technically, even the Romans were not able to get water to flow “up a hill”.
44. Will Water damage concrete?
As far as only concrete is concerned i.e. plain concrete, the effect of water seepage is very little (depending upon the grade of concrete) whereas for RCC (reinforced cement concrete) water that seeps in corrodes the reinforcement and thus reduces the life of the structure. The defects that water seepage induces in concrete are as follows:
- induces capillary formation (due to the deteriorating characteristics of water)
- With this capillaries the concrete starts spalling out; i.e. the places where capillaries are formed, with even slight amount of stress that portion comes out and exposes the steel to the atmosphere
- Concrete has a pH of about 12 -13. It also reduces the pH of the concrete when in salty water (or) when exposed to marshy areas.
- Reduces the overall strength of concrete
- Reduces durability
- Reduces permeability to further water seepage
- Results in ageing of structures
45. How do you determine Specific gravity of cement?
Cement is usually purchased as a powdery substance that is mixed with sand, aggregate, gravel, and water to form concrete. Since the cement itself is usually a powder, it is hard to measure a standard value for its specific gravity. In addition, since cement is usually not used by itself, knowing its specific gravity is not particularly useful.
A more useful question is “What is the typical density of concrete?” A rule of thumb answer is that normal cured concrete has a density of about 150 pounds per cubic foot. This includes the weight of the cement, sand, aggregate, and that part of the water that chemically binds with the cement to form the concrete. Since water weighs about 62.4 pounds per cubic feet, concrete is about 2.4 times as heavy. Thus, the specific gravity of concrete is about 2.4. If you took cement and mixed it with water, you would eventually have a hard lump of useless cement and it would also have a specific gravity of between 2 and 2.4.
46. Define What is the meaning of a blue land surveyors flag?
If the flag was placed by Utility personnel responding to a “One-call” locate request, the blue flag indicates a buried water line. You see these marked when a contractor calls the “Call before you dig number” a couple of days prior to excavating. This is required by law in each state to reduce the likelihood of damaging underground utilities when excavating.
The standard color code used by almost all utility companies for painting & flags is:
- White – “Here is the area I plan on excavating!”
- Blue – water line
- Red -electricity
- Yellow -natural gas
- Green -sewer
- Orange -telephone and/or fiber optic line
If the blue flagging was a fuzzy blue marker nailed to the top of a wood surveyor’s stake, then it probably serves to indicate the top of the grade at which the engineer wants the earthmoving equipment to place fill dirt. These are called “blue-top” stakes.
47. What are advancements in civil engineering?
Unlike other fields of engineering, the major advancement of the filed has been in the early years of the century before the last century where the use of concrete technology is advanced. The use of cement as a construction material is since the turn of the last century, improvement in the field increase by the use of steel elements in the construction of buildings and bridges of various types. With the help of two, it was possible to do multistory buildings in the world.
Machineries were created to speed up the construction structures. The last century has also seen the advent of sophisticated design to withstand the effect of earthquake that was not possible before. With the use of computers, development of model and analysis of structures under the effect of loads was made possible. Before just two decades, it used to take months and months to design high-rise building and big bridges. Now it is a matter of hours.
48. Why is the statue of liberty made of copper?
Copper is a very durable material when exposed to weather and is soft enough that it can be easily molded to curved shapes such as those in the Statue of Liberty. It is also traditionally used in buildings for complex roofs, so there would have been trades people available trained to use it.
Other metals that can be molded are lead but it does not have the attractive verdigris color, and gold much is more expensive
49. Are cruise ships built for the transatlantic run?
The Queen Mary 2 was built for transatlantic crossings, but much smaller ships can make the crossing easily. In 1995, I crossed the Atlantic from New York to the Azores on the Royal Princess (which was not the same ship as the current Royal Princess), which was about one-fourth the size of the QM2. Just about any seaworthy passenger ship can navigate the Atlantic safely, if not comfortably.
50. Define What is diversion tunnel in a dam?
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.
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51. What distance in meters on the ground is the equivalent of one second of arc in longitude or latitude?
- One minute of arc as measured at the center of the Earth covers one nautical mile on the surface of the Earth at mean sea level. One nautical mile is 6080 feet or 1853.2 meters. Therefore one second of arc would be 6080 / 60 = 101.3 feet or 30.886 meters.
- Lines of latitude are at regular intervals parallel to the equator. The relationship between degrees of latitude and the distance spanned on the earth’s surface remains constant. Therefore at all latitudes 1 minute of latitude spans 1 nautical mile on the earths surface.
- Lines of longitude converge at the poles. Therefore, the relationship between degrees of longitude and the distance spanned on the earth’s surface is reduced as the poles are approached.
- At the equator, the distance spanned by 1 minute of longitude would be 1 nautical mile. At the poles, it would be zero. To calculate the actual distance on the surface of the earth between two points of known latitude and longitude requires knowledge of spherical trigonometry to calculate the great circle distance between the two points.
- The distances quoted are for the surface of the earth at mean sea level. Distances will be increased above sea level and reduced below it.
52. How do you maintain water pressure?
If you have water pressure and wish to maintain it, do not cause flow in the line, which will reduce pressure due to friction. To keep pressure up, reduce friction by increasing the line size or eliminating some other restriction.
53. What are some facts about concrete?
Actually, drying is not directly linked to hardness in concrete. After concrete is poured, putting it in a wet environment by spraying it constantly with water will hasten its hardening and its curing. After concrete cures, it is hard.
54. Define Who designed the city of Washington DC?
55. Where is the worlds longest elevator and how long is it?
Gold mines in South Africa go a few kilometers below the surface. The deepest mine now is the Mponeng Mine in the Orange Free State. The depth of the mine is well over 3000m from the surface and is getting deeper. The lift itself descends 3037m to a point 1200m below sea level. It takes 4 minutes.
56. How many kilo-Newtons equals 1000 kilogram?
When the 1000 kg are at rest, on Earth with gravitational acceleration 9.81 m/s2, 1000 kg equal 9.81 kN.
57. How is the Leaning Tower of Pisa supported?
In the same manner, it was supported when it was constructed. However, it has gotten some “help” over the years.
In the last couple of decades, the responsible parties rolled up their sleeves and removed something approaching 40 meters3 of earth from under the higher side of the structure. This had the effect of straightening it toward the vertical by about a foot and a half at the top. For the first time in its history, it is no longer moving. In addition, in the good-news corner of the paper is that it is open to the public again. In addition, the folks who lived near the tower in the direction it was leaning have returned to their homes and do not have to sleep with an eye and an ear open.
58. What does civil engineering mean?
They do many interesting things. Their job has to do a lot with design and construction. They can tell you what works and what will not for all sorts of situations. There is a lot of mathematics involved along with many other disciplines. They have to have a good solid understanding of how the environment works and how nature interacts with man made. They are probably best known for designing bridges, interstates, skyscrapers, canals, and so forth.
59. How long does it take concrete to harden?
It takes 28 days to cure.
60. What is the biggest dam in America?
The Grand Coulee Dam – Grand Coulee, Washington
- Length 5,223 ft
- Height 550 ft
61. How does siphoning work?
Pretty good if the outside hose is a lot lower than the inside hose. The siphon works by a hose stuck in a fluid container higher than the receiving container. Suction is shortly placed on the lower side of the hose until the fluid is flowing down the down line. Gravity will cause a continued flow.
62. Why was the Empire State Building made of steel?
- Strength–Steel is very strong
- Flexibility–Ability to flex in the wind
- Cost–Inexpensive and fast to build; prefab construction
- Concrete, a possible alternative, has less compressive strength than steel. The bottom support structure of the empire state building would consist of a large percentage of solid concrete simply to support the weight of the building.
63. What is the quantity of cement in Mix M20 concrete?
For nominal Mix Cement consumption for M25 will be 570 kg per cum. and for Design Mix it can be optimized to 510 kg per cum.
64. Define What is unit weight of normal concrete?
65. What is the difference between shear and tensile strength?
Tensile Strength for a Bolt is determined by applying a Force along it long axis. Shear Strength for a Bolt is determined by applying a Force across its diameter, as it would be loaded in a lug joint.
66. How many Pyramid in Egypt?
67. Would you cause a 55-gallon drum of water to weigh more by climbing in?
A person will sink in water if he is not holding enough air in his lungs to keep him floating. Therefore, the person weighs more than the amount of water that he will displace.
68. Who built the sears tower?
While he did not build the structure (he died in l959), there is some evidence the idea was suggested under a different name (Illinois Building) by Frank Lloyd Wright, one of the few true skyscrapers in which he had a role. The original design for the Illinois Building would have topped off at 5,280 Feet! The Swears tower is a quarter of this at most, but there are similarities.
69. At what point does a circle start losing area when being flattened?
The area ratio decreases slowly at first then more rapidly.
The area of an ellipse is A=pi x a X b, a and b are the 1/2 major and 1/2 minor axis. If a = r = b the area is A=pi X r2, which is a circle. Not hard to graph this but you will have to write the area of the ellipse in terms of the circumference.
70. How do you compute volume of airflow?
Orifice meter is used for measuring flow rate air.
71. Define What is made from large rocks, which protects the base of cliffs?
72. Why are the bolts that hold steel rails together in oval holes?
It has to do with the design of the bolts. The reason that head of the bolt is oval. The head of a bolt fit flush into the bar and set in opposing sets is so that a piece of dragging equipment will not shear off all the bolts in a joint but rather the just the nuts one side. As a result, if the hole were not oval on one side there would be no way to tighten or loose the bolts in a joint.
73. Define What are the materials used in building a gravity dam?
There are many gravity dams constructed of compacted earth. High dams are generally concrete. All dams require a spillway to be safe. The spillway must be armored.
74. How many feet are in 4 square yards?
There are 9 square feet in a square yard therefore there are 36 square feet in 4 square yards.
75. What black man invented the clothes dryer?
George T. Sampson
76. What is the average density of soil?
For purposes of civil engineering, an average soil will have a density of about 100 to 110 pounds per cubic foot. (This can vary a little depending upon how well compacted the soil is.)
77. Define What glue is least sticky?
Elmer’s glue is least sticky.
78. What are the strongest shapes in building?
79. Which architectural movement is also known as Jazz Moderna?
80. What is the withdrawal force of steel nails?
In engineering, the code-allowable withdrawal force is zero, because the wood expands and contracts over time and the nail pullout force can reduce to zero.
81. What is the strongest bridge for a school contest?
If you are making a spaghetti bridge, bunch it all together in a triangular prism or a big brick and just fill the gaps with paste.
82. What is the formula for figuring out how many gallons of water are in a pipe by the foot?
0.61 * d2, where d is the diameter of the pipe in inches.
83. What is the tensile strength of marble?
Tensile Strength, Ultimate 7.00 – 20.0 Mpa 1020 – 2900 PSI
this is the strength in a pure tension test. For bending use:
Modulus of Rupture 0.00410 – 0.0276 Gpa 0.595 – 4.00 ksi
84. Did any of the Egyptian pyramids ever fall down?
Yes, many did. The great pyramid and others that have survived did so for a reason. Their shapes made them sturdier over time and were not the first design. Many steppe pyramids were built but were too steep and as the corners eroded, the whole pyramid fell under its own weight. They were built too steep and did not have the base structure as seen in the great pyramid.
85. Can a wave happen in the middle of the ocean like in the movie Poseidon 2006?
Yes. Rogue waves have been known to capsize ships.
86. Define What materials were used to build the Golden Gate Bridge?
Its materials were steel and concrete.
87. What is the density of most of construction materials?
If it floats it is less dense than water, 62.4 lbs/cubic ft. Wood is about 40 lbs/ cu.ft.–it floats. Concrete is 150 lbs. / cu.ft. — It does not float.
88. How and where are aqueducts built?
Aqueducts are built in areas where you have a bunch of motivated end users (like a town or group of farmers) at a low elevation in need of a more reliable source of water located somewhere fairly nearby at a higher elevation. The aqueduct builders construct a series of canals, elevated channels, and tunnels as required to get the water from the source to the end users. Some good examples:
- Roman engineers built aqueducts throughout Italy and France from mountain water sources to serve city dwellers
- Water-needy Southern California cities and farms are served by an aqueduct that brings them water from sources in Northern California
- New York City is supplied by an aqueduct and tunnel system from sources upstate.
- Inca farmers in coastal valleys built irrigation aqueducts from sources higher up in the Rockies
- Native American cultures in Phoenix area built irrigation canal systems that diverted water from sources at higher elevations to irrigate their crops.
89. Define What does civil status mean?
Civil means like, when you do not get on with someone, but only talk when you have to. Alternatively, when you do talk you do not argue. Alternatively, if you are with someone who is of your both friends and family, you do not ruin it for them.
90. What are the advantages and disadvantages of lead products in construction?
- Disadvantages: -Lead is very toxic; its use can result in pollution of the ground and more importantly of water supplies. This leads to the contamination of drinking water and can cause hazards to human health as well as disrupting entire ecosystems.
- Advantages: Because of its toxicity, lead is being bought less and less around the world, which of course results in the lowering of its cost. In addition, lead melts at a relatively low temperature, making it great for solder. However, recently the Chinese have show an interest in buying mass quantities to manufacture batteries made from a base of lead so the price of this metal may soon rise.
91. How do you measure water flowing through 300mm diameter pipes?
Same as in inches 3.14159265 and PSI have to be known.
92. Define the various stages of the project planning process in construction.
First stage could be Briefing and Inception.
93. How do you convert wind speed into force?
94. What is kn measurement?
kn (both letters lowercase) is knots, which is a speed nautical miles per hour.
95. What are the advantages of building a dam on the river Nile?
It is the same as building a dam on any river. Dams are built to control flooding downstream during the wet season, generate power year round, and provide irrigation in the dry season.
96. How much does the leaning tower of Pisa lean?
About 14 feet
97. Define What is the best type of wood glue?
98. Define What are the uses of Groynes?
They prevent, or slow down erosion, and stop long shore drift. This, however, can have bad knock-on effects somewhere near.
99. What are the functions of a column in a building?
A column is used to support the weight of the roof and/or the upper floors. Now days, many columns are used for decorative purposes. A column along with load bearing beams can support a lot of weight.
100. Define What is an ice dam sock?
If you have never used a ice dam melting sock on your roof before, you will find that they provide an inexpensive method for removing roof ice dams and improving your home’s heating efficiency. Roof ice dams are an annoying source of roof damage, leaks, and heat loss in the winter. The main causes are drip melt from improperly capped warm air vent pipes and poor roof insulation. Laying a ice melt sock onto the roof so it crosses the ice dam and overhangs the gutter, will melt through the snow and ice and create a channel for water to flow down into the gutters or off the roof. If done properly those ice sickles that form as the snow melts from the edges of the gutters will never appear, they too are a cause of much damage and are dangerous to life and limb.
CIVIL ENGINEERING Questions Answers ::
101. Define What happens to Load at yielding ?
A yield strength or yield point is the material property defined as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed.Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible. In the three-dimensional space of the principal stresses ( \sigma_1, \sigma_2 , \sigma_3), an infinite number of yield points form together a yield surface.
The yield point determines the limits of performance for mechanical components, since it represents the upper limit to forces that can be applied without permanent deformation. In structural engineering, this is a soft failure mode which does not normally cause catastrophic failure or ultimate failure unless it accelerates buckling.
Yield strength is the critical material property exploited by many fundamental techniques of material-working: to reshape material with pressure (such as forging, rolling, or pressing), to separate material by cutting (such as machining) or shearing, and to join components rigidly with fasteners.
102. What is Critical path in Ms-Project ?
The Critical Path consists of a series of tasks that must be completed on schedule for a project to finish on schedule. It is the series of tasks (or even a single task) that dictates the calculated finish date. Each task on the critical path is a critical task.
103. where will be the reinforcement of slab placed when there is an inverted beam and the bottom of the beam and slab are at same level ?
Irrespective of the type of reinforced concrete flexural element, the fundamental requirement is that tension reinforcement must be placed in that portion of the section which has tensile stresses. Depending upon the type of element and loading, tensile stresses may not be on the same (top or bottom) edge of the section. But it is very easy to determine the portion of the length of the element where tension is at the top and where it is at the bottom, by studying the bending moment diagram of the element. Reinforcement is placed on the compression side of the elements when it is required to increase the moment carrying capacity of the section beyond the limit possible for an under-reinforced section. Replacing a portion of concrete in compression by steel results in the compressive force and adding a little extra tension steel to balance the additional compression makes it possible to increase the moment of resistance without increasing the depth of the section.
Having said that, an inverted beam (with slab flush with the bottom of the beam) reverses the location of flange but not the bending moment distribution. So, positioning of reinforcement would be the same as an a normal beam. But it has an impact on the amount of reinforcement because of the changed flange location.
104. Define What is passive earth pressure ?
Passive earth pressure is the highest limiting lateral pressure developed at the onset of shear failure by wall moving (penetrating) in the direction opposite to the direction of acting earth pressure (minimal wall rotation necessary for the evolution of passive earth pressure is about 10 mrad, i.e. 10 mm/m of the wall height). In most expressions used to compute the passive earth pressure the sign convention is assumed such that the usual values of δ corresponding to vertical direction of the friction resultant are negative. The program, however, assumes these values to be positive. A seldom variant with friction acting upwards is not considered in the program.
105. Which condition will prevail for the design of a swimming pool ? when the pool is empty or when it is filled ?
Depends on many factors – like in-ground vs above-ground – but both is a good answer – in-ground an empty pool has to withstand the force of the earth pushing on it. Both when filled have to handle the force of the water on the shape of the walls and bottom.
106. Which is stronger solid steel rod or hollow steel pipe?
On a per pound basis, steel pipe is stronger in bending and is less likely to buckle in axial compression.
107. What is reinforced concrete?
Reinforced concrete have steels bars or mesh in them, which gives extra strength to the construction.
108. 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.
109. 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.
110. What are the common ways of demolition?
- Pressure Bursting
111. What is floating slab foundation?
A floating concrete foundation is a type of mat foundation that consists of the hollow mat formed by a grid of thick reinforced concrete walls between two thick reinforced concrete slabs.
112. What is flashing?
Flashing is an extended construction that is done to seal and protects joints in a building from water penetration. Flashing is installed at the intersecting roofs, walls and parapets.
113. Define different types of roof systems?
- Slate or Stone roofs
- Wood shingle roofs
- Metal roofing systems
114. What are the phases inspections are done by local authority while construction?
Various inspections during the construction includes
- Site Inspection
- Pre-construction or first construction Inspection
- Foundation inspection(before placing of concrete)
- Framing inspection ( before insulating or covering frame)
- Insulation inspection ( After insulation is completed)
- Final inspection (after all construction is completed, and permits are received)
115. List out some of the checking’s, done at the completion of construction?
Some of the checking done on the exterior of the construction is
- Utility connections
- Retaining walls
- Compaction of fill material
- Caulking at opening
- Storm sewer system
- Safety provision ( terraces, porches, areaways)
- Accessory buildings
- Pavement edging
- Protection against moisture penetration
- Design of dwelling structure
116. What is alternate bid?
Alternate bid is the amount stated in the bid to be deducted or added from the base bid amount. Alternate bid is proposed when there is a use of alternate materials or methods of construction.
117. What is change order request?
Change order request is a written document issued or given by the owner, requesting an adjustment to the contract sum or an extension of the contract time. Usually, it is issued by the architect or owners representative.
118. What does a construction cost covers and what does not?
A construction cost covers material, labor, equipment and services, contractor’s overhead and profit and other direct construction costs. While, it does not cover compensation paid to the architect, consultant or engineers, cost of the land and other cost that is owner’s responsibility.
119. What is Critical Path Method (C.P.M)?
Critical Path Method is strategy and method of representing the respective tasks and activities involved in the construction through a symbolic diagram.
120. What is demising walls?
Demising wall is used for the boundary that separates your land or house from neighbor’s house
121. What is labor and material payment bond?
It is a bond between the owner and the main contractor. Where a contractor guarantees for payment to the owner if he fails to pay for all labor, materials, equipment’s or services in accordance with the contract.
122. What is progress payment?
It is a payment done by owner to the contractor; it is a difference between the completed work and material stored and a pre-determined schedule of values or unit costs.
123. What is structural frames or systems?
Structural frames are a load bearing assembly of beams and columns on a foundation. Normally, the columns and beams are generally fabricated off site and assembled on site.
124. What is zoning permit?
Zoning permit is a document issued by governing urban authority permitting land to be used for a particular purpose.
125. What is the release of lien?
Release of lien is a written document executed by an individual or firm supplying labor, material or professional service on a project, which release his mechanic’s lien against the project property.
126. What is Architect-Prepared Contract?
Architect- Prepared Contract is an agreement prepared in-house by the architect between owner and architect, and often reviewed by an attorney, before its execution. It is a legal contract, and it includes all terms and conditions including adequate legal protection for both the parties.
127. What is 1/8 on the architect ruler denotes?
1/8 on the ruler is infact a scale that converts 1/8 inch on to the drawing to 1 foot. It would represent a drawing with a scale of 1/8”= 1 foot.
128. List out some of the software program that can be useful for architect?
software programs List
- 3DS Max
- Adobe creative suites
- Microsoft office
- Digital Media
129. What are the skills required to become an architect?
- Conceptual understanding of designing models
- Basic knowledge of computer and architect related software programs
- Engineering ability
- Business aptitude
- Legal knowledge
- Designing 3D models
130. What things architect have to take care of before starting any project?
- Whether the owner has proper planning permission
- Whether the building has a certain listed grade approved
- Knowledge of building appliances and materials that includes the cost as well
- Need to take environmental factors into consideration
131. 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
132. 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
133. Which are the top apps for you civil engineering?
Some of the top Apps
- Ever note
- Photoshop Express
- Magic Plan
- AutoCAD Ws
134. What are wooden shingles?
Wooden shingles are rectangular in shapes, and they are like slats or sheets that are nailed to the exterior surface. Shingling is a traditional weather proofing method for building.
135. List out some of the common problems that architect have to tackle it?
- When client is not sure about what they want
- When there is a limited budget
- When customer requires custom design at standard design cost
- When architect has to work with limited space
136. 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.
137. 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.
138. 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.
139. 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
140. 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
141. What things you need to take care of before building a kitchen island?
Before you start building a kitchen island, you need to take care of
- Design the kitchen island according to the need- if it is only for cooking purpose then use less space, but if it is also for eating then design it accordingly
- List out what appliances you need for your kitchen island
- How high the counter should be
- How much storage space should you required
- Working sides surrounding the kitchen island should have 42 inches of space as a minimum around the kitchen island. Don’t plan Kitchen Island if it makes your kitchen more congested.
142. 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.
143. 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)
144. 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
145. 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
146. What is OSHA compliance?
OSHA stands for Occupational Safety and Health Act; its motive is to fulfill the health and safety requirement of employees and workers. It is a standard for health and safety that is followed by every industrial segment and corporate offices throughout U.S.A.
147. What are the composition of a landfill?
For secure landfill, there are 4 critical elements
- The bottom liner
- A leachate collection system
- A cover
- Natural hydrogeologic settings
148. For the construction project what capital cost has to be taken in consideration?
- Land acquisition ( Assembly, holding and improvement)
- Planning and feasibility studies
- Construction ( Material, equipment, and labor)
- Construction financing ( Bank loan)
- Insurance and taxes during construction
- Owner’s general office overhead
- Inspection and testing
- Equipment and furnishing not included in the construction
- Field supervision, architectural and engineering design
149. List out some of the software used in the construction sector to estimate cost and monitoring expenses?
• Tally System
• Maxwell System
• Premier construction software
• Construction partner, etc.
150. In block work seawalls what is the purpose of slip joints?
Joints which are formed from the cope level to the toe level of seawalls through a complete vertical plane are known as slip joints. Such joints are designed so as to handle the differential settlements between the seawalls adjacent panels. In the slip joints the aggregates inside the half-rounds channels enables some vertical movements. These vertical movements are induced by differential settlements. This enables in the interlocking of the adjacent panels of the seawalls to link the panels in one unit against the earth pressure ( lateral ) which is exerted on the seawalls.
151. For a washout valve why are two gate valves required in normal practice?
The washout valves are primarily used for normal maintenance works such as that of water main. This can be like to allow water to flow out during the cleaning of the water main. The junctions at which a pipe branches out to a washout point usually a gate valve is installed so that the two pipelines are separated. The gate valve installed above usually remains open during normal operation. Another gate valve is installed further downstream and this remains closed during normal operation of the washout valve. In case this valve is not installed then the pipe section of the branched out pipe would remain dry during normal operation and high chances of damage and leakage can take place. When the downstream valve is installed the branched out water main contains water under normal operation. With two gate valves installed a leakage can be detected immediately.
152. What are the different approaches in designing the floors of the service reservoirs?
In general there are two main approaches of designing the reservoir floors to prevent leakage of water due to seasonal and shrinkage movements:
- In this approach the movement joints of the reservoir floor panels are such that the free expansion and contraction of the panels takes place. Every panel is isolated from the other panels and two panels have a sliding layer between them to help in sliding.
- The second method does not provide any room for free movement. With seasonal and shrinkage movements, some cracks are designed to voluntarily occur on the floors of the service reservoirs. These tiny cracks are spread throughout the floor and are simply too minute to cause any leakage or corrosion of the floors. But the difference also in this method is that the amount of reinforcement used is much more than the first approach.
153. Why concrete barriers have curved surface profiles?
The concrete safety fencing’s are made to contain vehicles in their carriageway being traveled so as to reduce the chances of rebounding into the roads leading to more hazards. In the case of normal fencing’s upon vehicle crashes the fencing’s give away so as to absorb as much energy as possible henceforth reducing the impact on the vehicles. But in the case of concrete barriers their purpose is not to absorb energy of vehicles crashing into the barrier but to retain them. They have a curved design so as to allow the vehicles that hit them to slightly go up on the barrier but not overturn. They also prevent the vehicle from again getting back on the road by rebounds. This helps in vastly reducing the chances of other vehicle hazards.
154. Why is the use of granular sub-base in concrete carriageways not preferred, explain?
Some of the reasons why granular sub-base is not preferred in concrete carriageways:
- Sub bases are permeable and hence water can seep through them easily. The soil particles get pumped out through the joints on the application of traffic loads. This results in the creation of voids underneath the pavement structure. This leads to the weakening of the concrete surface and it can crack easily upon intense traffic loads.
- Instead if lean concrete is used for carriageways it greatly increases the strength of the roads and the load carrying capacity of the roads is increased.
- Sub-bases implementation requires a lot of workmanship which can lead to an un-uniform distribution of the sub-base. This can lead to the cracking of the carriageway when there is severe traffic loading.
155. Why are separation membranes used between concrete pavement slab and sub-base?
The purpose of separation membrane between the concrete pavement slab and the sub-base are as follows:
- The separation membrane reduces the frictional forces between the concrete slabs and the sub-base. The membrane aids the movement of the concrete slab in reference to the sub-base when changes in the level of the moisture and temperature occurs.
- It aids in the segregation of sub-base materials from freshly placed concrete.
- The separation membrane also helps in the reduction of cement and water loss in the form of immature concrete. Immature concrete greatly affects the strength of the concrete. It also affects the durability of it.
A good example of a separation membranes is polythene sheeting which is commonly used.
156. In the roof of a pumping station explain briefly the components of a waterproofing system.
The components of a typical waterproofing system on the roof of a pumping station are as follows:
- Right above the structural finish level of the roof ( concrete ) a uniform thickness screed is applied so as to facilitate the application of the waterproofing membrane. The surface provide for the membrane should always possess good cohesion properties and must be thin so as to prevent any un-uniformity. This thin layer also acts as a layer of thermal insulation.
- Right above this layer the waterproofing membrane is deployed to secure the water tightness of the roof.
- In order to enhance the thermal insulation of the roof an insulation board is sometime placed right above the waterproof membrane. The insulation board helps in the maintenance of a stable temperature in both weathers.
157. During reclamation how can the occurrence of mud waves can be rectified?
There are several solution to the rectification of the problem of mud waves:
- Complete removal of all the disturbed mud: This method can be considered to be one of the fastest methods. As soon as the disturbed mud is removed some filling material is used to replace the disturbed mud. But economically this method can be expensive as compared to others.
- Accelerated consolidation of disturbed mud: In this method surcharging loads are placed on top of the mud waves. Along with this band drains are installed to accelerate the consolidation process. This method is quite slow compared to the other methods.
- Partial removal of the disturbed mud: This method is the hybrid of the above two methods where the top layer is removed whereas the lower level is treated with the surcharging process.
158. In reclamation works what are the importance of geotextiles and sand?
The primary purposes of geotextiles and sand in reclamation works are as follows:
- Geotextiles: They are used to separate the marine mud from the reclamation fill. Also geotextiles are used as reinforcements in reclamation processes to increase its stability. It is still debated as to whether the usage of geotextiles is better or are the old processes followed are better as the performance has not been comparable to the conventional methods.
- Sand: In reclamation process sand is used to spread the load of any future public dumps placed on top of it. Sand also acts as a drainage for the excess pore water pressure of band drain installations.
159. What are the different type of slump test indications?
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:
- True Slump
- Shear Slump
- Collapse Slump
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.
160. Why is propping required for long structures once the formwork is removed?
Once the process of concreting is performed the striking of the formworks should be done as soon as possible as delay in this process can lead to the discoloration of the concrete structures. In case of long structures particularly long span structures once the structures have attained enough strength to support themselves it is essential to provide them with propping as creep deflection can take place which can greatly reduce the integrity of the structure. Due to the above mentioned reasons propping should be done after the removal of formwork. Also the props should not be made to stand long as it can lead to overstress for the structures.
161. Explain the mechanism of cavitations in pipes and drains?
The formation of air bubbles in a fluid due to low pressure conditions lower than the saturation pressure is known as cavitations. This is considered to be a high potential damage condition where the strength and durability of the pipes can be greatly reduced. Cavitation works on the principle of Bernoulli’s Equation. When fluids are at high velocities the pressure head of fluids reduce accordingly. But since the fluid pressure is lower than the saturation pressure the dissolved gases get released from the flowing fluid. These air bubbles suddenly collapse on entering a region of high pressure. This leads to the damage of the pipelines as a high level of dynamic pressure is created.
162. For what purpose bedding is used under storm water drains, explain?
Beddings are primarily made up of granular or concrete materials. They are primarily used for the following purposes:
- They are used to provide a more uniform support for the under pipes so that the bending moment longitudinally can be reduced greatly.
- In order to enable the pipes to get more load-supporting strength.
- They are also used to act as a platform to achieve a more correct alignment and level pre and post construction.
- In case of pipes which contain spigot and socket joints, it enables pipes to get supported along pipe lengths in place of sockets. Otherwise it can lead to uneven stress being induced on the pipes eventually damaging it.
163. Why are pull-out tests performed for soil nails?
Pull out tests are performed for primarily the following reasons:
- In order to detect and the verification of the bond strength among the soil and the grout adopted during the design of soil nails. This is considered to be as the primary objective of performing pull out tests for soil nails.
- For the detection of any slippage or occurrence of creeps.
- To detect the elastic and deformations (plastic) of any of the test nails employed. Observations are made during the loading and unloading cycles of the soil nails repetitively.
- To achieve the perfect balance the test nails should always be loaded so that the ultimate soil/grout mixture with an upper limit of 80%.
164. Explain briefly the advantages and disadvantages of using plastic and timber fenders?
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 depends on the point of contact. Also since they are made from recycled material they are environmental friendly.
The advantages and disadvantages of using timber fenders are:
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.
165. In the design of bridge arguments what considerations should be made to select the orientation of the wing walls?
Some of the most common arrangements of wing walls in cases of bridge arguments are as follows:
- Wing walls parallel to abutments: This method is considered to take 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 slope embankment.
- Wing walls at an angle to abutments: This design method is considered to be the most economical in terms of material cost.
- 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.
166. In case if concrete box girder bridges how is the number of cells determined?
When the depth of a box girder bridge exceed 1/6th or 1/5th of the bridge width then the design recommended is that of a single cell box girder bridge. But in case the depth of the bridge is lower than 1/6th of the bridge width then a twin-cell or in some cases multiple cell is the preferred choice. One should also note that even in the cases of wider bridges where there depths are comparatively low the number of cells should be minimized. This is so as there is noticeably not much improvement in the transverse load distribution when the number of cells of the box girder is higher than three or more.
167. Under what circumstances should pot bearings be used instead of elastomeric bearings?
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.
168. Why should pumping be not used in case of concreting works?
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 pump able, 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.
169. Why should curing not be done by ponding and polythene sheets?
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 off 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.
170. What are the steps involved in the concreting process, explain?
The major steps involved in the process of concreting are as follows:
3. Transporting and placing of concrete
- 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.
171. 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:
(a) Spraying of water: on walls, and columns can be cured by sprinkling water.
(b) 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: 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.
(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.
172. What do you understand by “preset” during the installation process of bridge bearings?
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 of the following components:
- Length of bearing
- 2 x irreversible movement.
- 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 is 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.
173. Why are steel plates inserted inside bearings in elastomeric bearings?
In order to make a 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.
174. 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.
175. How cracks in concrete can be avoided?
176. 28 Days Strength of Concrete (1:2:4)?
177. Strength of brick?
178. what is Brest Wall?
179. what is Brick crushing strength(PSI)?
180. what is Bearing Capacity,How to determine it?
181. How much is the curing time period?
182. How many types of slabs are there & how to design it?
183. How many are the types of joints?
184. Why joints are provided?
185. How many bricks are there in 100cft?
186. Types Of DPC and its Thickness used?
187. How many bricks are there in 100 cft?
188. Which are the Steel tests ?
189. How much is the cover for slab?
190. What is packing Factor ?
191. Forces in a Shear Wall are in plane or out of plane ?
192. What is fineness modulus ? and its sieve # ?
193. What is Base Shear ?
194. What is Time period of a building and its relation with frequency ?
195. There are two buildings one taller and one shorter whose time period will be grater and similarly the frequency ?
196. Define Workability ?
197.Sulphate Resisting Cement ?
198. Special thing in designing a overhead reservoir ? which is different from an ordinary design
199. Maximum %age of Steel in columns and beams ?
200.Types of foundation?