Increase in fineness of cement results in?
Fineness of cement is property of cement that indicate particle size of cement and specific surface area and indirectly effect heat of hydration. Fineness of cement affects hydration rate hence the rate of strength gain.
The smaller the particle size, the greater the surface area-to-volume ratio, and thus, the more area available for water-cement interaction per unit volume.
Therefore, finer cement reacts faster with water and the rate of development of strength and corresponding heat of hydration is high. Hence with increase in fineness of cement, rate of hydration increases but the total amount of heat generation will remain same.
A brick laid with width parallel to the front direction of wall is:
The ingredient of paint which are used to hide the surface irregularities and imparts colour is known as ________.
Pigments are used to hide the surface imperfections and to impart the desired colour. They protect the paint film by reflecting the destructive ultraviolet light which acts as a catalytic agent for the destructive oxidation of the film.
Drier are used in paints for specific purpose e.g. as catalyst for the oxidation, polymerisation and condensation of the vehicle in paint. The quantity of drier is limited to 8%, excess of it affects the elasticity of paints leading to flaking failure.
Adulterants bring down the overall cost, reduce the weight and increase the durability. Adulterants also help to reduce cracking of dry paint and sometimes help to keep the pigment in suspension. Example Barium sulphate, calcium carbonate, magnesium carbonate etc.
Solvents are the oils used to thin the paints, increase the spread and are also known as thinners. Example-Spirit, naphtha and turpentine oil.
What is the representative geometric mean size of an aggregate sample if its fineness modulus is 3.0?
The fineness modulus is a numerical index of fineness which represents the mean size of the particles present in the aggregates.
As per IS 2386 (Part - I) - 1963, sieves used in calculating fineness modulus are:
80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 μm, 300 μm and 150 μm.
Counting the sieve from finest one to identify the sieve corresponding to the fineness modulus of the sample.
For fineness modulus of 3.0, corresponding sieve is 600 μm.
When cement and lime are used in definite proportions as binding material, the type of mortar is known as:
Gauged mortar: It is a mixture of cement, lime, sand and water. The process of adding cement to lime mortar to improve its quality is termed as gauging and mortar thus prepared is known as gauged mortar.
Lightweight mortar: It is the type of mortar which is prepared by mixing saw dust, rice husk, jute fibers, coirs, asbestos fibers etc. along with sand and lime or cement.
Windows where shutters open like doors are termed as:
__________ is used to ensure that the thickness of plastering is uniform.
Plastering thickness is marked by the Bull marks. For internal plastering 12 to 15 mm will be the average thickness. Plaster thickness, Plump, wall lines & right angles are considered while fixing Bull marks.
Bench mark is the point on the ground whose reduced level is known to us.
Which of the seasoning method is adopted for the rapid seasoning of timber on large scale to obtain any desired moisture content?
Kiln seasoning: Kiln is an airtight chamber, timber to be seasoned is placed inside it then fully saturated air with a temperature 35°C to 38°C is forced in the kiln. The heat gradually reaches inside timber. Then relative humidity is gradually reduced, and temperature is increased, and maintained till desired degree of moisture content is achieved. This method is used for seasoning on a larger scale for rapid seasoning.
Boiling: In this method timber is immersed in water and then water is boiled for 3 to 4 hours. Then it is dried slowly. Instead of boiling water hot steam may be circulated on timber. The process of seasoning is fast, but costly.
Air and water seasoning of timber are the natural process of seasoning.
A sample of cement is said to be sound when it does not contain free
Soundness of cement is affected by the presence of excess lime (CaO) in the cement. This excess lime hydrates very slowly and forms slaked lime that occupies a larger volume than the original free calcium oxide.
The slow hydration process, therefore, affects the properties of hardened concrete. The difference in the rate of hydration of free lime and slaked lime leads to change in volume of hardened concrete. The cement which exhibits this type of volume changes is described as unsound cement.
The defect in timber that causes longitudinal separation of woods between the annular rings is known as ________.
Shakes: Shakes are nothing but cracks which separates the wood fibres partly or completely. Depending upon the type of prevailing condition, different types of shakes are formed such as Cup shakes, Heart shakes, Ring shakes, Star shakes and Radial shakes.
Rind galls are curved swellings of trees which are formed at a point where a branch of the tress is improperly removed or fell down.
Knots: Knots are the most common defects caused due to natural forces. During the growth of a tree, branches close to the ground or lower branches die. Bases of those branches remain in the tree as the trees grow. These bases may create imperfection known as knots.
Twisted fibres: These are known as wandering hearts and caused by twisting of young trees by fast blowing wind. The timbers with twisted fibres are unsuitable for sawing.
A revised estimate is prepared when the expenditure on the work exceeds or likely to exceed the amount of administrative sanction by more than:
Revised estimate is a detailed estimate and is required to be prepared under any one of the following circumstances:-
1) When the original sanctioned estimate is exceeded or likely to exceed by more than 5%.
2) When the expenditure on a work exceeds or likely to exceed the amount of administrative sanction by more than 10%.
3) When there are material deviation from the original proposal, even though the cost may be met from the sanctioned amount.
The quantity of brickwork in a semi-circular arch of 3.50 m span and 30 cm thickness of arch and 35 cm breadth of wall?
The value of the property obtained after deducting the amount of yearly repairs from the gross income is known as:
Rateable value: It is the net annual letting value of a property, which is obtained after deducting the amount of yearly repairs from the gross income.
Annuity: It is the annual periodic payments for repayments of the capital amount invested by a party.
Capitalised value: It is the amount of a money whose annual interest at the highest prevailing rate of interest will be equal to the net income from the property.
In case of steel rolling shutters, for estimation of painted area, the plain area is multiplied by ______:
i) For fully glazed or gauged door, multiplying factor should be 0.80.
ii) For Flush door, multiplying factor should be 1.20.
iii) For Roof battens, multiplying factor should be 0.80.
iv) For steel rolling shutter’s, multiplying factor should be 1.10.
Which of the following item is NOT a lump sum item?
Sometimes a lump - sum rate is provided for certain small items for which detailed quantities cannot be taken out easily or it takes sufficient time to find the detail such as front architectural or decoration work of a building, fire place, site cleaning, dressing, Electrical installation and Contingencies etc.
Plastering of wall can be accurately measured that’s why it is not included in lump - sum items.
When actual cost of construction plus certain profit is paid to the contractor then such a contract is known as:
Work order: This is a contract and specifies the approximate quantities of different items of work, detailed specifications of each item of work, time for completion of the whole work, penalty etc. Small work up to Rs. 2,000 may be carried out by work order.
Cost plus percentage contract: In this type of contract, contractor is given certain percentage over the actual cost of the construction as his profit. Contractor arranges materials and labour at his cost and keeps proper account and he is paid by the department or owner the whole cost together with certain percentage, say 10% as his profit as agreed upon beforehand.
15 m3 of mild steel weights about:
One m3 of mild steel weighs about 7850 kg
For 15 m3 of mild steel:
Weight = 15 × 7850 = 117750 kg
Which of the following is not included in the “Outgoings” while valuation of a building?
Outgoings are the expenses which are required to be incurred to maintain the revenue of the building. The various types of the outgoings are as follows:
i) Taxes: Municipal tax, Property tax, Wealth tax etc
iii) Management and collection charges
iv) Sinking fund
v) Loss of rent
vi) Miscellaneous: This includes electric charges for running lift, pump, for lightning common places etc
Note: Capital cost is the total cost of construction including land, or the original total amount required to possess a property. It is the original cost and does not change.
A property in delhi fetches a net annual income of Rs. 1150 after deducting all the outgoings. The Capitalised value of the property if the rate of interest is 7.5 % per annum is?
Capitalised value (V) of the property is given by:
V = Net income x Year purchase
Year purchase = 100/7.5 = 13.33
Net income = Rs. 1150
V = 1150 × 13.33 = Rs. 15333.33
Who among the following has full authority to technical sanction the work up to Rupees 1 crore?
i) Chief engineer has full power to technically sanction the work with no limits.
ii) Superintendent engineer has power to technically sanction the work up to rupees 1 crore.
iii) Executive Engineer has power to technically sanction the work up to rupees 40 lakhs.
iv) Junior Engineer has no power to technically sanction the work.
Spire test is to check which of the following permanent adjustments of the theodolite?
Remember the following test:
Spire test: It is a test carried out to remove Error due to non-perpendicularity of the horizontal axis and the vertical axis in surveying Instrument.
Crosshair ring Test: This test is done to make the vertical crosshair lie in a plane perpendicular to the horizontal axis.
Plate level Test: This test is done to make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical
Vertical arc Test: This test is done to make the vertical circle indicate zero when the line of sight is perpendicular to the vertical axis.
Removal of parallax in a theodolite can be achieved by focusing:
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight.
The temporary adjustments of a theodolite are:
i) Setting over the station
ii) Levelling up
iii) Elimination of parallax
Elimination of parallax:
Focusing the eye-piece: To focus the eye-piece for distinct visions of the cross-hairs, hold a sheet of white paper in front of objective and move eyepiece in and out till the cross hairs are seen sharp and distinct.
Focusing the objective: The Telescope is now directed towards the object to be sighted and the focusing screw is turned till the image appears clear and sharp.
A substance bar can be used to determine:
Substance bar: A horizontal bar used in the subtense system of surveying by tacheometry. It is held at a distant point and its distance is calculated from its known length and the angle that it subtends at the observer's eye.
Which of the following is the expression for the additive constant, if f is the focal length of objective and i is the stadia interval?
Tacheometry is one of the methods used in surveying to accurately measured the horizontal distance between two inaccessible points on the ground.
Horizontal distance from instrument station and ground point is given by:
D = ks + c
k = multiplying constant
i = stadia interval
f = focal length of the objective
k = f/i
c = additive constant
c = f + d
Number of links in 30 m chain for per meter run is:
Number of links in 30 m chain is = 150
For 1 meter run,
Number of links per meter run = 150/30 = 5
Note: Number of links in 20 m, 10 m and 5 m chain is also 5.
The length and breadth of a field of area 33600 m2, on map is 12 cm and 7 cm respectively. The R.F of the scale will be?
Length in map = 0.12 m
Breadth in map = 0.07 m
Map area = 0.07 × 0.12 = 8.4 × 10-3
Field area = 33600 m2
Representative scale =
Which of the following represents the percentage limit of porosity of the compacted sand?
Porosity (η) is defined as the ratio of volume of voids to the total volume of the soil sample in a given soil mass.
The porosity of soils can vary widely.
The porosity of loose soils can be about η = 50 to 60%.
The porosity of compact soils is about η = 30 to 40%.
What is relative density of sand if the sand in-situ is in its densest state?
If the sand is in its densest state, then
eo = emin
A soil sample is partially saturated, its natural moisture content was found to be 22% and bulk density 2 gms/c.c, the void ratio of the sample is?
Bulk density of partially saturated soil sample is given by:
Using the relation,
Se = wG
γ = 2.0 gm/cc
G = 2.65
Grain size of soil indicats that D10 = 0.004 mm. D30 = 0.002 mm and D60 = 0.007 mm. The coefficient of gradation of soil is
The coefficient of Gradation is also known as the coefficient of curvature and It is given by
The slope of isochrones at any point at a given time indicates the rate of change of
The slope of isochrones at any point at a given time indicates the rate of change of pore water pressure with depth. Within the consolidation process of a saturated clay a gradual decrease in neutral pressure and a gradual increase in effective pressure takes place and sum of the two is constant.
In the flow over length of 50 m, the head loss of 6 m occurred due to seepage. The hydraulic gradient is given by_____.
Hydraulic gradient (i) is defined as the head loss per unit length of the specimen.
hf = 6 m
L = 50 m
The effective stress within a soil mass is mainly a function of the:
Effective stress is equal to the total vertical reaction force transmitted at the points of contact of the soil grains divided by the total area, including that occupied by water. It is the pressure transmitted from particle to particle through their point of contact through the soil mass.
For the purpose of foundation design, silt can be classified as:
Silt is classified as C - ϕ soil. That’s why it has limited cohesive properties.
C = Cohesion
ϕ = Angle of internal friction
For a base failure of a finite slope the depth factor:
For base failure depth factor,
Where h height of the slope.
So for base failure
For toe failure
For face failure
Where is the regulating valve provided in a centrifugal pump
Two Pelton wheels A and B are having same specific speed and are working under the same head. Wheel A provides 900 kW at 800 RPM. If wheel B produces 100 kW, then its RPM will be
For same specific speed and working under the same head i.e.
Bluff body is the body of such a shape that pressure drag as compared to friction drag is
What is the cross-sectional area (sq. m) of the channel, if its hydraulic radius and wetted perimeter is given as 300 cm and 860 cm respectively?
Hydraulic radius is given by =
Area = 258 × 103 cm2
Area = 25.8 m2
According to principle of floatation, the weight of liquid displaced as compared to the weight of the body is
The purpose of surge tank is ________.
The hydraulic radius in the case of an open channel with great width is equal to
Which of the following conditions will be satisfied by steady irrotational flow?
For steady, irrotational flow following two condition must be fulfilled:
i) flow possibility
ii) ωz = 0
(flow is possible)
(flow is irrotational)
In a triangular notch, there is an error of 6% in observing the head. The error in the computed discharge is
For triangular weir or notch,
Intensity of irrigation…
The percentage of CCA (culturable commanded area) proposed to be irrigated in a given season is called intensity of irrigation.
The annual irrigation intensity is usually found to be in the range of 40 to 60%. But needs to be raised in the range of 100 to 180% by cultivating larger parts of CCA with more than one crop in a year.
The optimum depth of kor watering for wheat crop is:
The first watering which is given to a crop, when the crop is a few centimetres high is called Kor watering.
The optimum depth of kor-watering for different crops are different.
i) The optimum depth of kor-watering for rice is 19 cm.
ii) The optimum depth of kor-watering for wheat is 13.5 cm.
iii) The optimum depth of kor-watering for sugarcane is 16.5 cm.
Duty of canal water will be less if:
The duty of the water represents the relationship between the volume of water and the area of the crop it matures. It may be defined as the number of hectares of land irrigated for full growth of the crop by a supply of 1 m3/sec of water continuously during the entire base period of that crop.
Relation between Delta (∆) and Duty (D) is given by:
As the duty of canal is less, depth of water required (Known as delta ∆) will be more.
The ordinate of the Instantaneous Unit Hydrograph (IUH) of a catchment at any time t, is
The limiting case of a unit hydrograph of zero duration is known as instantaneous unit hydrograph (IUH). The ordinate of one IUH at any time ‘t’ is the slope of S – curve of intensity 1 cm/hr.
Which of the following is/are correctly associated with functions of sleepers:
1. Holding rails to correct gauge.
2. Transferring the loads from rails to the ballast.
3. Providing effective drainage to track.
Select the correct answer using the options given below:
Wooden, cast iron or R.C.C. members which are laid transverse to the track alignment to support the rails and to transfer the load from the rails to the underlying ballast are called sleepers.
Effective drainage to track is provided by ballast.
Which chemical indicator turns water into pink colour, if the pH is more than 8.3.
pH of the water can also be measured by certain indicators:
1.Phenolphthalein: Phenolphthalein indicator works in the pH range of 8.6-10.3. Phenolphthalein is often used as an indicator in acid-base titrations. For this application, it turns colourless in acidic solutions and pink in basic solutions, that's why if the pH of the water is more than 8.3 it turns the water into pink colour.
2.Methyl orange: Methyl orange indicator works in the pH range of 2.8-4.4. The original colour of this indicator is red and the final colour is yellow.
Water requirement per day per bed in a hospital is?
As per IS 1172:1993, water requirement for buildings other than residences are:
The maximum permissible total solid content in water for domestic purposes should not exceed:
As per IS 10500:1991:
The desirable limit of total solid content in water for domestic purposes should not exceed 500 ppm.
In case of absence of alternate sources, the permissible limit specified is 2000 ppm.
The main disadvantage of oxidation pond is that
Oxidation ponds are large, shallow typically 1-2 m deep, where raw or partially treated sewage is decomposed by microorganisms. The conditions are similar to those that prevail in a eutrophic lake.
This method would also have disadvantages that it requires extensive land area, potential odour problem, mosquito menace, little control over the effectiveness of the treatment process and the main disadvantage is seepage of effluents into soil which may also lead to ground water pollution.
If the temperature of a sedimentation tank is increased, the sedimentation speed will:
Where T = temperature in oC
From the equation Vs∝T
So as temperature increases the settling velocity also will increase.
Which of the following is a disadvantage of traffic signals?
Following are the disadvantages of traffic signals:
i) large stop time delay
ii) Complex signal design problems
The possible effect of poorly timed traffic signal is:
i) Increase in vehicle delay
ii) increases vehicle crashes particularly rear end crashes
iii) Disruption to traffic progression
In Water Bound macadam roads, the binding material is:
Water bound macadam roads:
The roads whose wearing course consist of clean crushed aggregates, mechanically interlocked by rolling and bound together with filler material and water and laid on a well-compacted base course, is called water bound macadam road.
A gradient along which the vehicle does not require any tractive effort to maintain a specific speed is known as:
Floating gradient:- The gradient on which a motor vehicle moving with a constant speed continues to descend with the same speed without any application of power brakes is called floating gradient i.e the vehicle does not require any tractive effort to maintain the specific speed.
Minimum gradient:- The minimum desirable slope essential for effective drainage of rainwater from the road surface is called minimum gradient
Exceptional gradient:- The gradient steeper than the limiting gradient which may be used in short length of road, only in an extraordinary situation is called exceptional gradient.
Ruling gradient:- The gradient usually adopted while making the road alignment is called the ruling gradient. It is the maximum gradient within which the designer attempts to design the vertical profile of a road. It is also known as design gradient.
What is the mechanical widening required for a pavement of width 7 m on a horizontal curve of radius 490 m, if the longest wheel base of vehicle expected on the road is 7.0 m?
Mechanical widening (Wm) on road is given by:
As width of pavement = 7.0 m, this implies number of lanes are 2.
So, n = 2
l = length of wheel base = 7.0 m (given)
R = radius of the curve = 490 m
For a steel built-up column subjected to an axial force of 1200 kN, the lacing system is to be designed for resisting transverse shear of:
Lacing system in a column is designed for transverse shear of 2.5 % of column load.
If ‘p’ is the basic wind pressure, for buildings with large opening design pressure on a wall is taken as:
Design pressure is taken as:
Cpe = External pressure coefficients
Cpi = Internal pressure coefficients
For highly permeable buildings have more than 20 % openings,
Cpi = ±0.7
P = ±0.7p
A column member of length “L” which cannot sway has a rigid foundation at its bottom. Its top is held with heavy beams. The effective length of the column is:
The covering of concrete placed on the external top of an external wall is known as:
Coping: It is a course placed upon the exposed top of an external wall to prevent the seepage of water.
Cornice: It is a projecting ornamental course near the top of a building or at the junction of a wall and ceiling.
Lintel: It is a horizontal member of stone, brick, wood, iron or RCC used to support the masonry or load above an opening.
Consider the following statements:
High early strength of cement is obtained as a result of
1. Fine grinding
2. decreasing the lime content
3. Burning at higher temperatures
4. Increasing the quantity of gypsum
Of these statements
High early strength of cement is obtained as a result of:
1. Fine grinding
2. Increasing the lime content
3. Burning at higher temperatures
4. Decreasing the quantity of gypsum.
Basically, C3S is responsilble for the early development of strength in the concrete.
A floor constructed with the 4 to 6 mm marble chips, is known as:
Terrazzo flooring consists of:
i) Concrete bed
ii) Mortar bed, 1 cm of cement mortar (cement sand mixture 1 : 3)
iii) Metal strips
iv) marble chips 3 to 6 mm.
Mosaic flooring consists of Concrete layer, A layer of cementing material of about 3 mm thick (consisting 2 : 1 : 1 ratio of lime and marble and pozzolana material), marble pieces or tiles.
Marble flooring: Marble slabs are cut to get marble tiles of 20 to 25 mm thickness. They are laid on floors similar to other tiles. With power driven machine surface is polished to get even and shining surface. This type of flooring is widely used in hospitals and temples.
Bleeding is good to an extent if it occurs when concrete is:
Bleeding is a form of segregation in which water present in the concrete mix is pushed upwards due to the settlement of cement and aggregate.
The specific gravity of water is low, due to this water tends to move upwards. Bleeding ordinarily occurs in the wet mix of concrete.
The Prime factor for bleeding in concrete is the high dosage of Water cement ratio. Higher water-cement ratio weakens concrete and leads to excessive bleeding.
Early bleeding when the concrete mass is fully plastic, may not cause much harm, because concrete being in a fully plastic condition, will get subsided and compacted. It is the delayed bleeding, when the concrete has lost its plasticity, which causes undue harm to the concrete. That’s why, Bleeding is good to an extent if it occurs when concrete is placed.
Which of the following concrete has auto crack healing capacity?
In bacterial concrete when cracks appear in a concrete structure and water starts to seep in through, the spores of the bacteria start microbial activities on contact with the water and oxygen. In the process of precipitating calcite crystals through the nitrogen cycle, the soluble nutrients are is converted to insoluble CaCO3 and remediate the cracks.
Excess vibration during compacting of concrete can lead to:
Compaction significantly increases the ultimate strength of concrete and enhances the bond with reinforcement. It also increases the abrasion resistance and general durability of the concrete, decreases the permeability and helps to minimise its shrinkage and creep characteristics.
Proper compaction also ensures that the reinforcement, tendons and fixings are completely surrounded by dense concrete, the formwork is completely filled i.e. there are no pockets of honey-combed material and that the required surface finish is obtained on vertical surfaces.
For most of concrete mixes, over-vibration creates the problem of segregation in which the denser aggregates settle to the bottom while the lighter cement paste tends to move upwards.
According to I.S. specifications concrete should be cured under a humidity of?
Curing of cement concrete is defined as the process of maintaining the moisture and temperature conditions of concrete for hydration reaction to normal so that concrete develops hardened properties over time.
The time to start curing of concrete depends on the evaporation rate of moisture from the concrete. The evaporation rate is influenced by wind, radiant energy from sunshine, concrete temperature, climatic conditions, relative humidity.
According to Indian standard specification,
Concrete should be cured under a humidity of 90%.
Under normal conditions using ordinary cement, the period of removal of the form work, is
Impact strength of concrete is greater for:
i) water stored concrete than for dry concrete
ii) angular crushed aggregates
iii) rounded aggregates
The correct answer is:
Impact strength of concrete is assessed usually by the ability of a concrete specimen to withstand repeated blows and to absorb energy.
The impact strength of water stored concrete is found to be lower than when the concrete is dry.
For the same compressive strength, impact strength is greater for concrete made with coarse aggregate of greater angularity and surface roughness. Angularity number for angular crushed aggregate is more than that of rounded aggregate, therefore impact strength of angular crushed aggregate is more than that of rounded aggregates.
In the concrete mix with proportions of its ingredient 1:3:6, the actual quantity of sand per unit volume of cement, if bulking of the sand is 15% is ______.
Bulking Of Sand: The volume of dry sand increases due to absorption of moisture.
The concrete mix proportion is 1:3:6,
Let volume of cement to be 1 m3
Volume of sand = 3 x 1 m3 = 3 m3
The volume of coarse aggregate = 6 m3
Incorporating 15 % bulking of sand,
Volume of sand required per unit volume of cement is = 1.15 x 3 = 3.45 m3
Required sand is greater in case of bulking than in case of normal condition.
Which of the following tests compares the dynamic modulus of elasticity of samples of concrete?
The static modulus of elasticity does not truly represent the elastic behaviour of concrete due to the phenomenon of creep. Ultrasonic pulse velocity measures the dynamic modulus of elasticity which is higher than those determined by static method because the dynamic method is unaffected by creep.
How does the strength of concrete differ with age of concrete?
The degree of hydration is synonymous with the age of concrete provided the concrete has not been allowed to dry out or the temperature is too low. It is seen that majority of strength gain by concrete is achieved in 28 days and the rest is continuous throughout the life of concrete. Concrete mainly gains strength by hydration of water present in it, this will lead to decrease in water cement ratio and increase in strength of concrete.
Therefore, Strength of concrete increases with age.
The specification for coarse and fine aggregates is conducted as per:
The batching tolerance for aggregates as per IS 456 is?
As per IS 456: 2000 clause 10.2.2,
The accuracy of the measuring equipment shall be within ±2% of the quantity of cement being measured.
The accuracy of the measuring equipment shall be within ±3 % of the quantity of aggregate, admixtures and water being measured.
Which one of the following is the correct range of fineness modulus of medium sand usable in preparing cement mortar?
Usually stiffness of a simply supported beam is satisfied if the ratio of its span to depth does not exceed which one of the following?
For cantilever and continuous beam the ratio of span to depth to satisfy stiffness criterion shall not exceed 7 and 26 respectively.
(clause 23.2.1 of IS: 456-2000)
In case of eccentrically loaded struts _________is preferred.
In case of eccentrically loaded struts, there is bending stress along with direct axial stress and the twisting moment is also acting on the structure. The hollow section has more moment of inertia, so hollow section is preferred in case of an eccentrically loaded strut.
What is the anchorage value of a standard hook of a reinforcement bar of diameter 16mm?
As per clause 220.127.116.11, the anchorage value of standard U type hook shall be equal to 16 times the diameter of the bar.
So anchorage value is 256 mm.
A flat slab is supported _____.
Flat slab is supported on columns monolithically built with slab. Flat slab is provided when there is a restriction to provide beams due to space constraint and when large openings are desirable for better natural lighting.
When Mild steel bars are used in place of HYSD steel bars, the Bond strength:
As per IS 456:2000:
The bond strength of HYSD bars is 60% more than the bond strength of mild steel bars for the same grade of concrete used.
So, if mild steel bars are used in place of HYSD steel bars, the bond strength of concrete decreases but development length required will be more.
A 200 mm thick brick masonry wall made of modular bricks is 5 m long between cross walls and 3.8 m clear height between RCC slabs at top and bottom. The slenderness ratio of the wall is:
The slenderness ratio of the wall is lesser of
So, slenderness ratio of the wall is 19.
The thermal expansion coefficient α of steel is:
The thermal expansion coefficient of steel (αsteel) is equal to thermal expansion coefficient of concrete αconcrete.
αsteel = αconcrete = 12 × 10-6/oC
That’s why RCC is widely used in civil engineering practise.
Compared to plain bars, the deformed bars will have
Compared to plain bars, the deformed bars will have a better bond due to corrugation. The ultimate and yield strength of deformed bars are higher than that of plain bars (mild steel bars), so the design with deformed bar is also economical.
According to load factor method, the permissible load W on a short column reinforced with longitudinal bars and lateral stirrups is ________.
The short column will fail by crushing or yielding of material.
The load carrying capacity of short column is = Stress in concrete x area of concrete + stress in steel x area of steel
Side face reinforcement is provided in a beam is:
Side face reinforcement in the web of the beam is provided when the depth of the web in a beam exceeds 750 mm. (0.1% of the web area and shall be distributed equally on two faces at a spacing not exceeding 300 mm or web thickness whichever is less).
A bar having length L and uniform cross-section with area A is subjected to both tensile force P and torque T. If G is the shear modulus and E is the Young’s modulus, the internal strain energy stored in the bar is
The elastic strain energy stored in a member of length s (it may be curved or straight) due to axial force, bending moment, shear force and torsion is summarized below:
Strain energy due to combined effect of load P and torque T:
The maximum twisting moment a shaft can resist, is the product of the permissible shear stress and_______.
Thus the maximum twisting moment a shaft is the product of the permissible shear stress and polar modulus (ratio of the polar moment of inertia to the radius of the shaft).
A steel rod of 2 cm diameter and 5 m long is subjected to an axial pull of 3000 kg. If E = 2.1 × 106 kg/cm2 the elongation of the rod will be:
Elongation of rod is given by:
P = 3000 kg
E = 2.1 × 106 kg/cm2
D = diameter = 2 cm
L = length = 5 m
Determine the shape of the elastic curve between the supports B and C for the beam as shown in the figure below.
The elongation (mm) in a steel bar having a square cross section of dimension 40 mm x 40 mm is 2.5 mm and is subjected to an axial compressive load of P (kN). If the length of the bar is 4 m and modulus of elasticity is E = 250 GPa. What is the value of P (kN)?
Which of the following assumptions is INCORRECT about the long column?
The following assumptions are made in the Euler’s column theory about long column:
The diameter of shaft A is twice the diameter of shaft B and both are made of the same material. Assuming both the shafts to rotate at the same speed, the maximum power transmitted by B is
A beam cross-section is used in two different orientations as shown in figure given below:
From the simple bending theory equation:
If σb is the maximum bending stresses due to bending moment M on shaft:
For same bending moment:
So σA = 2 σB
In the case of bi-axial state of normal stresses, the normal stress on 45° plane is equal to
In the case of bi-axial state of normal stresses:
Normal stress on an inclined plane:
Shear Stress on an inclined plane:
Normal stress on 45° plane:
Which of the following statement is CORRECT for the modulus of resilience?
Proof resilience is defined as the maximum energy that can be absorbed within the elastic limit, without creating a permanent distortion.
The modulus of resilience is defined as the maximum energy that can be absorbed per unit volume without creating a permanent distortion (i.e. The proof resilience per unit volume of a body is called modulus of resilience).
When bending moment M and torque T is applied on a shaft then equivalent torque is
In some applications the shaft are simultaneously subjected to bending moment M and Torque T.
From the simple bending theory equation:
If σb is the maximum bending stresses due to bending moment M on shaft:
The maximum shear stress developed on the surface of the shaft due to twisting moment T:
Equivalent Bending Moment:
The degree of indeterminacy of pin-jointed truss shown in fig -
Ds = Dse + Dsi – R
Where Dse = External indeterminacy = r – 3
Dsi = Internal indeterminacy = m – (2j – 3)
R = Release = 0
∴ Dse = 3– 3 = 0
Dsi = 11 – (2 × 6 – 3) = 11 – 9 = 2
∴ Ds = Dse + Dsi – R
A fixed beam AB is subjected to a triangular load varying from zero at end A to ‘w’ per unit length at end B. The ratio of fixed end moment at B to A will be
The following two statements are made with reference to the place truss as shown below.
I. The truss is statically determine.
II. The truss is kinematically determinate.
With the reference to the above statements, which of the following applies?
Dc = m – 2j + 3
= 9 – 12 + 3 = 0; i.e. the frame is statically determinate.
Dk = 2j – 3 – m
= 12 – 3 – 9 = 0; i.e. the frame is kinematically determinate.