Society for Training & Research on Panchayats and Rural Development.
[HANDBOOK OF NIRMAN SAHAYAK] Society For Training And Research on Panchayats & Rural Development
Government of West Bengal Jessop Building ,63 NS Road ,Kolkata -700001
CONTENT
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1. What are the properties of 1st class Bricks?
Ans. It should be thoroughly well burnt preferably in kiln uniform deep red
cherry or copper coloured, regular in shape & size, distinct edges and should emit clear ringing sound when struck against another brick, free from cracks, when immersed in water in a vat for 24 hrs. It should not absorb more than 10 to 15% of its weight. The conventional size of bricks 9 ¾” x 4 ¾” x 2 ¾” & the weight is approximately 3.50 Kg. each.
2. How many types of bricks & what is the limit of water absorption by bricks?
Ans. The types of bricks are as follows with the limitation of water absorption: a) 1st class bricks – not more than 10% of weight. b) 2nd & 3rd class bricks – not more than 20% of weight. c) Fourth class bricks. d) Picked jhama bricks.
3. What are the crushing or compressive strength of bricks?
Ans. 1st class bricks – 126 kg/cm2
2nd class bricks - 105 kg/cm2 3rd class bricks – 56 kg/cm2 Picked jhama bricks – 140 kg/cm2
4. What are the tests of good bricks? Ans. i) When struck with each other they should emit clear ringing sound.
ii) Should be sufficiently hard & leave no impression when scratched with finger nails. iii) Should not break when dropped on hard ground from a height of about one meter iv) Limit of water absorption when soaked continuously for 24 hrs, are varying 10-20% for different class of bricks.
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5. What are the Common Construction Materials used in the Construction
Works? Ans. Marbel Moorum Brick Cement
Sand Stone Granite Brick bats Sand Slate Lime Stone Jhama bats Surkis Laterite Kankar Jhama Metal Timber Bitumen Grit Stone Lime Glass
Steel
6. What are different forms of lime used in construction works?
Ans. It is in the form of lime stone named Calcium Carbonate. It is generally available as:
i)Non hydraulic lime ii)Semi hydrated lime iii)Hydraulic lime (Eminently hydrated)
Lime may be classified as Class A – Eminently hydraulic lime (contained 25-30% of clay) which is
used for foundations & hydraulic structures. Class B - Semi hydraulic lime (containing 15-20% of clay used for
mortar in masonry work). Class C – Fat lime (high calcium oxide content) used chiefly for lime
punning, white washing. Lump lime: It means quick lime as its comes directly from kiln(CaCo). 7. What are the terms of ‘Surki’ & ‘Sand’? Ans. It is termed as ‘artificial puzzolona’ obtained by girnding fresh burnt bricks, brickbats, broken tiles, pottery which should be fairly burnt of light red colour and with no portions remaining unburnt. Best Surki is obtained from burnt clay containing 15-20% lime. Sand is a form of Silica (SiO) is formed by disintegrate of rocks caused by weather. It should be free from silt and organic matter, should have coarse, angular grains of pure silica. Grains of sand should be hard, durable & strong. Classification as follows:
a) Pit Sand b) River Sand c) Sea Sand Functions: It is used as adulterant to increase the volume of mortar, it prevents shrinkage and cracking of mortar in setting and to improve the strength of mortar as sand has greater crushing strength.
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8. What about ‘Cement’ and their types. Ans. In the most general sense of the word, ‘Cement’ is a binder a substance that sets and hardens independently and can bind other materials together. Modern concrete this was made from crushed rock with burnt lime as binder of volcanic ash and pulverized brick additives that were added to the burnt lime to obtain a hydraulic binder were later referred to Cement. Some common types of cement as are follows:
a) Ordinary Portland cement b) Low heat cement c) Blust furnace slag cement d) Rapid hardening cement e) High alumina cement f) Quick setting cement g) Coloured cement h) Water proofed Portland cement
9. What is Concrete? Ans. . Concrete is a mixture of fine aggregate (sand), coarse aggregate (stone chips, gravel, jhama khoa) and matrix (cement) in combination with water as per proportion for the exact workability (water : cement ratio) of concreting. Excess water reduces t 9.a) What is the meaning of Development length?
Ans. Whenever some reinforcing bar is to be anchored or two bar have to be given an overlap, it is essential that they must get sufficient length of embedment or overlap on the case may be, so that no slippage takes place. The length of embedment (Ld) or development length.
Ld= Ø σ s /4 τbd Ø= Bar diameter
σ s = Actual tensile or compressive stress in bar
τbd = Permissible average bond stress. Its value depends upon the concrete, strength, the concrete cover and the type of bar used i.e. whether plain or deformed.
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The length of lap for reinforcement bar in tension shall not be less than Ld or 30 Ø, whenever is greater.
The length of lap for reinforcement bars in compression shall not be less than Ld or 24 Ø whichever is greater
The anchorage value of standard U type hook alone is equal to 16 Ø, where Ø is the diameter of a reinforcement bar.
The letter M refer to the mix and the number denotes the ultimate compressive strength of 150 mm cube at 28 days expressed in N/mm²
b) What is Columns?
Ans. A structural member, carrying on axial compressive load is called a strut. A vertical strut, used in building, is called a column.
c) What is long & short Columns?
Ans. A column is generally a compression member having an effective length greater than three times the least lateral dimension, when the ratio of effective length of the column to its least lateral dimension does not exceed 12, then it is termed on a short column. When the ratio of effective length to its least lateral dimension exceeds 12, then the column is considered on along or slender column.
The area of longitudinal reinforcement in a column should not be less than 0.8% of the area of the concrete section required for direct load.
The diameter of longitudinal bar should not be less than 12 mm.
d) What is slab?
Ans. The slab are plane structural members whose thickness is quite small as compared to its other dimensions.
When the ratio of long span to short span is greater than or equal to 2, then the slab is known on or slab spanning in one direction or one way slab. When the ratio of long span is less than 2, then the slab is known as a two way slab.
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If the plan bar are used, then the area of distribution reinforcement in slabs should not be less than 0.15% of gross c/s area of concrete.
e) What is the meaning of Foundation?Classification of foundation?
Ans. Foundation is the part of a structure whose function is to distribute the load of super-structure over a large bearing area. The foundation increase the stability of the structure and prevent the lateral movement of the supporting material. The lower most portion of a foundation which is in direct contact with the sub soil it is called footing.
According to Tezzaghi, a foundation may be broadly classified on shallow foundation and deep foundation. According to Tezzaghi, a foundation is said to be shallow if the depth is equal to or less than its width. In case of deep foundation, the depth is equal too greater than the width.
According to IS-456-1978, the thickness at the edge in reinforced and plain concrete footing on soils shall not be less than 150 mm and not less than 300 mm above the top of piles for footing on piles.
Minimum depth of footing, according to Rankine’s formula:-
D=P/W [1- Sin Ø/1 + Sin Ø] ²
P= Safe bearing capacity of soil in KN/m²
W= Unit weight of the soil in KN/m²
Ø= Angle of repose of the soil.
f) What are the uses of Retaining Walls?
Ans. The retaining wall are used to retain earth fill or any other material so that the ground surface at different elevations are maintained on either side of the retaining wall. These are mostly used for road in hilly areas, swimming pools, at the end of the bridges in the form of abutments, and under ground water tank.
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g) What is the meaning of Bond Stress?
Ans. When the steel bars are embedded in concrete, the concrete after setting, adheres to the surface of the bars and thus resist any force that tends to pull or push this rod. The intensity of this adhesive force is called bond stress.
According to I.S. Specification (IS-456-1978) the permissible value of bond stress for MIS grade of concrete is limited to 1N/mm.
h)What is Curing?
Ans. It is the process of hardening the concrete mix by keeping its surface moist for a certain period, in order to enable the concrete to grain more strength. The object of curing is to prevent the loss of water by evaporation, to reduce of concrete and to preserve the properties of concrete.
i) What is Compaction?
Ans. It is the process of consolidating concrete mix after placing it in position. The main aim of consolidation of concrete is to eliminate air bubbles and thus to give maximum density to concrete. The proper consolidation ensures intimate contact between the concrete and the surface of reinforcement.
10. How to measure a stack of materials?
Ans. Qty = (Upper Area + Lower Area )/2 x Height (Av.) 11. What are the different proportions for the plaster works applied for? Ans. For the exterior wall surface 6:1 (15 mm)
For the interior wall of the same 6:1 (20 mm) Outside of the plinth wall 4:1 (15 mm) For the ceiling 4:1 (10 mm)
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12.What is reinforced Concrete?
Ans. A reinforced concrete is one in which concrete has been reinforced i.e. strengthened by introduction of some other material normally torque steel to ensure strength, serviceability & life span etc. 13. What are the quantities of mortar in different proportions for 1m³ of brick work? Ans. Porportion Brick Cement Sand 2:1 389 0.15m³ 0.30m³ 3:1 389 0.107m³ 0.33m³ 4:1 389 0.083m³ 0.33m³ 6:1 389 0.055m³ 0.33m³
14. What are the types of Glass as construction materials used?
Ans. a) Sheet glass j) Ribbed glass k) Reinforced wire safety glass l) Laminated safety glass
15. What is ‘Timber’ & what are the names for common uses? Ans. Timber is a very important material for building construction. It is primarily required for two purposes:
a) For making doors & windows b) For structural use as rafting, reapers & purlains
Common uses of timber as follows: Sal, Teak, Mehagony, Sundari, Siris, Arjun, Jaruh, Jack, Bakul, Mango, Pia Sal, Mugra, Gamar,Akashmani,Sishu,jam,Neem
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15 (I). How can be differentials of % saving for a low cost saving by using the alternative materials in place of conventional option?
Innovative Techniques
Conventional option % of Saving
A) Foundation i)Pile foundation Traditional Brick 15 (Fifteen) ii) Brick Arch Works/Boulder works 25 B) Walling i)Stabilized Mud Block Burnt Brick Work 20 ii) Fly ash brick wall Green Brick work 20 iii)Fungi(Fly ash: Lime : Gypsum) Block
Green Brick work 25
iv) Hollow Block wall Solid Masonry 20 v) 150-200 mm Stone Block
Random Rubble Stone Masonry
20
C) Lintel i)Precast thin lintel R.C.C. lintel 25 ii) Brick on end edge lintel
R.C.C. lintel 50
iii) Corbelling lintel R.C.C. lintel 40 iv) Brick Arch lintel R.C.C. lintel 30 D) Doors / Windows i)R.C.C. door frames Wooden frame 30 ii) Frame less door Wooden frame &shutter 50 iii) R.C.C. Window frame
Wooden frame 30
iv) R.C.C. Jellies Ventilators 50
Room height to be maintained minimum 2.40m considering the low cost housing scheme
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SOIL MECHANICS
17. What is Soil erosion? Ans. Soil erosion means loss of soil from a particular area and this happened due to: a) Soil erosion by water (Ns¡­e¡ Sm­pË¡­al fËi¡­h ru) b) Salt affected (­e¡e¡ S­ml fËi¡h) c) Water logging (SmhÜa¡)
Erosion Soil Erosion Morpho Erosion Erosion due to Flood, Sea waves
(¢nm¡Ù¹­ll ru)
Sheet Erosion Gully Erosion
(Q¡c­ll BL¡­l ¢hÙ¹£ZÑ (S­ml ¢eL¡n£ e¡m¡l Hm¡L¡l ru) L­mhl hÑ¢ÜS¢ea ru)
d)Degraded forests. 18. What are the Indian Soil classification system? Ans. All Soils as per the Indian Soil classification system are divided into three main groups such as:
a) Coarse grained soils having more than half the total material by weight, larger than 75 micron sieve size.
b) Fine grained soils, having more than half the total material by weight smaller than 75 micron sieve size.
c) Highly organic soils, these soil contains larger percentages of fibrous organic matter such as peat and particles of decomposed vegetation. In addition certain soils containing shells, cinders and other non-soil materials in sufficient quantities are also included in this group.
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19.What is the classification of Soil? Ans. As per I.S. Code of practice 1498-1970, the soils are classified as below according to their sizes:
Boulder - above 300 mm Cobble - 300 – 75 mm Coarse Gravel - 75 – 20 mm Fine Gravel - 20 – 4.75 mm Coarse Sand - 4.75 – 2 mm Medium Sand - 2.00 – 0.425 mm Fine Sand - 0.425 – 0.075 mm Silt - 0.075 – 0.002 mm Clay - below 0.002 mm
Selection of Soil for Road Construction
Engineering construction like buildings are to be made over soils generally in
natural state, but construction of many other Civil Engineering structures like
roads or embankments involves use of the soil in remoulded conditions.
Selection of soil for those projects, therefore, needs careful considerations.
Nature and physical characteristics of soil are of prime importance in the
selection process. Soil profile of the area is recorded for use in design of
embankment and pavement. The following are some of the important features
in the task of soil selection:
Easiness in handling
Suitability for use in
Kankar, river sand-gravel mixes etc
Location of possible borrow areas along or off the road alignment
Identification and classification of soil
Homogeneity of the soil
Liquid Limit and Plastic Limit tests
Standard Proctor Density and O.M.C. tests
Deleterious constituents (only in salt infested areas)
CBR tests.
For highly plastic, poorly draining and unstable soil —
In addition to the above tests, the following tests are needed:
Consolidation tests
Physical requirements:
The materials shall be soil, moorum, gravel, a mixture of these. Such
materials shall be free from logs, roots, stumps, rubbish or any other
ingredient likely to deteriorate or affect the stability of
embankment/subgrade.
Specifications:
subgrade/embankment:
Materials from swamps, marshes and bogs
Peat, log, stump and perishable material ( any soil classified as OL,
OI, OH in IS:1498-1970)
Materials in frozen conditions
Materials with salts resulting in leaching in the embankment
Expansive clays: Free swelling index > 50, shall not be used as
filling material
Embankment= not exceeding 75mm
Subgrade = not exceeding 50mm
Embankment (upto 3metres height): not less than 1.44 gm/cc
Embankment (exceeding 3m height): not less than 1.52 gm/cc
Subgrade and earthen shoulders: not less than 1.65 gm/cc
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Physical requirements:
The material shall be natural sand, moorum, gravel, crushed stone,
crushed slag, granulated slag, crushed concrete, brick metal and
kankar. The material shall be free from organic or other deleterious
materials.
Specifications:
The material shall have 9 percent fines value against 50 kN load
Water absorption shall not be more than 2 percent
For higher water absorption Soundness test shall be carried out
CBR value shall not be less than 15%
Plasticity Index shall be less than 6%
Liquid Limit shall be less than 25%
Materials for Base course
Water Bound Macadam (WBM) is one of the commonly used base course.
There are three Grades of WBM constructions:
Grade Size range of aggregates
I 90mm to 45mm
II 63mm to 45mm
III 53mm to 22.4mm
Grade Size range
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Flakiness Index: not more than 30 percent
Water absorption: not more than 3 percent
Specification for binding materials ( loose soil): Plasticity Index shall be between 4 to 6
Liquid Limit shall be less than 35%
Black Cotton Soil :- It is expansive in nature and often found in varies parts of
West Bengal. Apart from large volume increase on increase of water content
and development of huge swelling pressures when volume change is restricted,
shrinkage also occurs at the several conditions.
V1 – V2 1 Shrinkage ratio (S.R.) = . w1 – w2 Vd
where, V1 = Volume of Saturated soil at water ω1
V2 = Volume of Saturated soil at water ω2
Vd = Volume of dried soil
V1 – Vd Degree of shrinkage or Volume Shrinkage = V1
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TRANSPOTATION ENGINEERING
20. How many steps for making building & roads? Ans. It has three parts mainly: Building: a) Foundation Roads: a) Sub-grade or formation b) Plinth b) sub-base course c)base course
c) Superstructure d) Surfacing
21. What are the real steps taken for making rural roads? Ans. a) Fixing Alignment
c) Preparation of estimate and sanction of fund c)Preparation of embankment by cutting soil & dumping & spreading
d)Preparation of Sub grade & layout d) Box cutting e) Brick Soling / Edging f) Base course g) Surfacing
22. Do you know the CBR & its test procedure? Ans. The most widely used test for foundation and of design of flexible pavement is the California Bearing Ratio test. The test was originally developed by the California Division of Highways by O.J.Porter and a design methodology was evolved from survey of pavement conditions carried out in California in 1920. Now most of the countries in the world adopt this standard method. The basis of design of flexible pavements in India too is the CBR method.
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LABORATORY CBR TESTSETUP
This test basically a penetration test, in which the load required to cause a plunger of standard size to penetrate a specimen of soil at a standard rate is measured.
The test can either be conducted on remoulded specimens or undisturbed specimens in the laboratory on in-situ of the sub-grade soil itself.
23. What is the reason for making ‘camber’ in a road? Is it compulsion? Ans. The reason for making in a road as follows:
h) Rain water/surface water easily flows towards the lower level. ii) Special facilities may be availed for the moving vehicles/cars.
Yes it is compulsion for making Camber in a road. 24. For strengthening of the rural road surface which one is best between moorum with laterite boulder or slag boulder? Ans. For this, the slag boulder is not suitable as because moorum & slag boulder will not make bonding when mixed with water. But laterite boulder easily makes bonding with moorum when mixed with water.
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25. What are the major important considerations for fixing the alignment of Rural Roads? Ans. The various important considerations to be kept in view at the time of designing the road alignment are as follows:
a) A site visit should be made and all relevant information collected on aspects like soil type, cross drainage works required, relative utility of the alternatives in terms of providing connectivity to Market, Health Centre, Educational Institution & other Social facilities.
b) Run the alignment on as high a ground as possible. c) Run the alignment on soils which provide better sub grade support. d) Study the problem of land acquisition; obtain local support for acquiring
the needed land width. Utilize the existing facilities of cart-tracks to the extent possible.
e) Avoid marshy and water logged areas, areas of poor sub grade support. f) An ideal alignment should involve minimum construction, maintenance
and travel operation costs g) Blind curves should be avoided as far as possible so as to give the
needed safe sight distances. h) Needless rise and fall should be avoided. i) Major Gross-drainage & protection works should be avoided to the extent
possible. 26. What are the side slopes to be maintained for rural roads of normal embankments? Ans. Side slops for rural roads of normal embankment are as follows Embankment in Silly/Sandy/Gravelly - 2:1 Embankment in clay soils - 2 ½ :1 to 3:1 Cutting Silly/Sandy/Gravelly Soil - 1:1 to ½:1 Cutting in Soft rock - ¼:1 to 1/8:1 Cutting in hard rock - Near vertical 27. What are the Camber to be maintained in rural roads for different surface types? Ans. Surface type Camber % Rigid pavement - 2.0 to 2.5 Thin Bituminous pavement - 3.0 to 3.5 WBM or Gravel - 3.5 to 4.0 Earth - 4.0 to 5.0
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27 .i)l¡Ù¹¡ Ll­a ­L¡e machine L¡­S m¡­N Hhw capacity La? Ans.
Road Roller m¡­N [8 – 10 T, 4 – 6 T, 1.5 – 2 T] capacity
28. Do you know the details of 8-10T three wheeled Road Roller Ans. This is most common equipment for compaction. It is diesel powered, the BHP being around 35. The diameter of the front roll is around 105 cm. its width being around 100 cm. The diameter of the rear roll is around 145 cm. its width being around 50 cm. The rolling width is around 2 meters. The front roll gives a load of around 35-40 kg/cm width and the rear roll gives a load of 70- 80 kg/cm width. The speed of rolling is in the range of 1.5 to 6.0 kmph. 29. What is the real output of 8-10T Three Wheeled Rolls for diff. works per day of 8hrs. Job? Ans. Following are the output (Average Operating conditions):
1. Earthwork/moorum/gravel/soil stabilization 6 passes - 425 cm³/day of 8hours. 9 passes - 300 m³/ day of 8hours. 12 passes - 200 m³/ day of 8hours.
2. Water Bound Macadam - 40 m ³/ day of 8hours. 3. Premix Carpet - 500 ²m/ day of 8hours. 4. Seal Coat - 900 m²/ day of 8hours. 5. Bituminous Macadam - 300 m²/ day of 8hours. 6. Asphaltic Concrete - 300 m²/ day of 8hours.
30. What do you mean by weep holes? Ans. Weep holes are provided to prevent building up of hydrostatic pressure behind abutment and wingwall of the height of abutment or wingwall over bed level is more than 2m, weep holes should be provided 150mm dia. In 1:20 slope. Intervals normally will be 1m c/c zigzag .
31. What is Turfing? Ans. In most of the rural roads, erosion of the slopes of the embankments rain cuts and erosion of the earth in the Shoulder are commonly observed
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defects. The erosion of the slops causes the loss of the roadway width, besides leading to sedimentation of the adjoining water bodies& natural drainage channels. This must be arrested by applying grass sods in the embankment slopes and earthen shoulders called turfing. Provision must be made in the estimates for this item. 32. Draw standard road Cross Section of Flexible Pavement.
33. Draw road Cross Section of RIGID PAVEMENT
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34. What are the Steps for pavement Design of a Flexible Pavement? Ans. The following procedure should be adopted:
a) Determine the field moisture content and the field density. Collect a representative sub grade soil sample for laboratory tests.
b) The field moisture content & field density determinations must be carried out at a number of locations, not less than 3 per Km. length of the road. For different types of soil and for sets of different drainage conditions, the number of field test must be suitably increased.
c) Prepare laboratory CBR samples of sub-grade soil confirming to the density and moisture content determined from field test for each of the locations.
d) Determine the CBR value of sub-grade soil for each location selected for field tests as at (a) & (b) above
e) Evaluate the traffic parameter by carrying out 24hrs. Field traffic counts during the lean season and during the harvesting seasons, finally arriving at the Average Annual Daily Traffic (AADT). A suitable rate of growth can be selected depending on the economic potential of the area.
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f) Determine the thickness of the pavement at each of the locations of field tests. The quality of the material for the overplay will depend on the quality of sub-base and base materials used in the pavement.
35. What are the Elements of Quality Assurance System of a Rural Road?
Ans.
Choice of quality materials and design: evaluation Pavement Thickness and composition for the assessed traffic and subgrade conditions to rest the design
riding quality
Fielf supervision and quality control of materials, construction technique, surface finish to desired profile
Assessment of quality of finished road
Periodic inspection and maintenance measures
Successful fulfillment of requirements of the project
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36. What are the stepwise procedure for one coat and two coat surface dressing?
Ans. i) The aggregates and binder should be checked for specification requirements. ii) All depressions and pot holes etc. on the receiving surface should be corrected iii) The surface should be cleaned by brushing to ensure that there is no loose material before binder is applied. IV) No surface work shall be carried out if the atmospheric temperature is less than 10° C The base or is damp The construction materials are damp The weather is foggy, rainy or dusty. v) The works should be organized that no traffic or dust gets on to the cleaned base. vi) The rate of spray of binder & temperature at the time of application should be checked. vii) Immediately after application of binder, the aggregated should be uniformly spread with the use of brooms viii) The rolling of aggregates shall commence immediately from the edges progressing gradually towards the centre parallel to the centre line. At super elevation, it should proceed from inner edge to outer edge. ix) Rolling operations to be continued till aggregates are firmly embedded in binder x) No traffic should be allowed for 24hrs.
xi) Finished surface should be checked for cross & longitudinal profiles being 3m straight edge.
Bitumen temperature 160 degree
Laying temperature 135 degree
Rolling 110 degree
37) What are the stepwise procedures for the specified thickness of premix carpet? Ans. a) The aggregates and the binder should be checked as per requirements
b) The surface should be suitably prepared with the correction of depressions & potholes etc.
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c) No loose material should be on the prepared surface. d) Prime coat should be applied as per procedure using the sprayer e) Tack coat should be applied at the specified rate uniformly on the
prepared base. f) Mixing of aggregates & bitumen in specified quantities should be
carried in a Hot Mix Plant (Mini) preferably 6T/hr capacity controlling with the temperature
g) The premixed material should be spread evenly to the specified thickness & camber. The cross fall should be checked by camber board.
h) Rolling should begin at the edges and progress towards the centre wheels of the roller should be kept moist.
i) Rolling should be continued until all the roller marks eliminated. j) Seal coat should be applied to the surface immediately after laying the
surfacing. k) The finished surface should be checked for lime level & regularity
using camber board/straight edge. 38. What is called culvert? Ans. A Culvert is a cross drainage structure having a total length 6m or less between the interface of dirt wall or extreme vent way boundaries.
39. What are the types of culverts? Ans.
a) R.C.C pipe culvert b) R.C.C. slab on masonry c) R.C.C. box type culvert d)Arch Culvert e)Vented causeway f) Submersible bridge
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WATER HARVESTING & CHECK DAM
40. What is the meaning of ‘Rain Water Harvesting’ & its different construction Component? Ans. Where there is no surface water or ground water is deep or inaccessible due to hard ground condition, or where it is too salty, acidic or otherwise unpleasant or unfit to drink, another source must be sought. In areas which have regular rain fall the most appropriate alternative is the collection of rain water, called “Rain water harvesting. The typical roof top rain water harvesting system comprises
Roof catchment Gutters Down pipe & first flushing pipe Filter Unit Storage Tank
What is check dam? A check dam is a small, temporary or permanent dam constructed across a drainage ditch, swale, or channel to lower the speed of concentrated flows for a certain design range of storm events. Purpose: Reduced runoff speed reduces erosion and gullying in the channel and allows sediments and other pollutants to settle out. They are inexpensive and easy to install. They may be permanent if designed properly and can be used where it is not possible to otherwise divert flow and stabilize the channel. Limitations Check dams should be used only in small open channels that drain 10 acres or less. The dams should not be placed in streams. The maximum height of the
RAIN WATER HARVESTING SYSTEM
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check dam should be 2 ft (0.6 m). The center of the check dam must be at least 6 in (152 mm) lower than the outer edges. They may kill grass linings in channels if water stays high or sediment load is great. Materials A check dam can be built from logs, stone, or pea gravel-filled sandbags.
After construction of check dam Construction of check dam
Installation Check dams can be constructed of either stone, or logs. Log check dams are more economical from the standpoint of material costs, since logs can usually be salvaged from clearing operations. However, log check dams require more time and hand labor to install. Stone for check dams, on the other hand, must generally be purchased. However, this cost is offset somewhat by the ease of installation. If stone check dams are used in grass-lined channels which will be mowed, care should be taken to remove all the stone from the dam when the dam is removed. This should include any stone which has washed downstream. Since log check dams are embedded in the soil, their removal will result in more disturbance of the soil than will removal of stone check dams. Consequently, extra care should be taken to stabilize the area when log dams are used in permanent ditches or swale
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CROSS SECTION OF HAND TUBE WELL
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DPR & TENDER
41. What are the Steps for preparation of DPR for road project Ans. DPR means Detail Project Report should be prepared in such a way that its gives a comprehensive account of different features of the project and should be presented under the following sub heads:
a) Preliminary Details: Name of the work, broad scope, plan provision reference to road plans, climate, need & priority of the Project.
b) Route selection: Considerations governing route selection, merits & demerits of alternative routes, investigations and reasons for selecting the proposed route.
c) Land acquisition plan: These are prepared for the survey drawings for land acquisition details.
d) Road features: The road features should be provided in detailed containing various aspects such as : i)Alignment: Topographical & Geographical ii) Environmental issues & mitigation measures: Air pollution to life system, drainage pattern, vegetation.
iii)Proposal of right way, acquisition of structures. iv)Traffic Survey: Projected period of 10yrs. & present status.
V) Road Design & Specifications: Geometric design of road, pavement design, retaining works, specifications. vi) Cross drainage structures: Investigation, details of design proposal & drawings of CD structures. vii) Material, labour & equipment: Availability, suitability, lead dirts
mobilization of resources. viii) Rates: Schedule of rates adopted, analysis, consideration of price
escalation contingencies ix) Construction programme: Total period of execution x) Miscellaneous: Diversion of traffic, arrangement of water supply & other
site amenities.
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42. What do you mean by ‘Tender’? Ans. Any constructive works proposed for execution by contract will be notified in a form of invitation called Tender & posted in Public places as per the approval of the Authority. 43. What are the steps taken for Tender procedures of a work? Ans. Tender invites in different shapes considering the nature of works such as : NIT (Notice Inviting Tender) NIQ (Notice Inviting Quotation) For execution of works-estimates prepared as per PWD Schedule of rates for roads, buildings, structures & S&P works. The item rate available in the schedule of rates and notified in a form of invitation called NIT (Notice Inviting Tender) And the items specification prepared and the rates not available in the schedule of rates – in that case it is notified in a form of invitation called NIQ (Notice Inviting Quotation). 44. What is called ‘Vetting’? Ans. The estimates prepared for a particular project which is to be sent to the Authority for sanction of the same. Before sanctioning of the estimate, the same to be checked technically as per drawing, designs & plans and also with the schedule of rates. If it is found OK in all respect by the Technical Authority, the same should be agreed by him with the written words ‘vetted by me’. And then the estimates will be given Administrative Approval and financial sanction. 45. How many types of Tenders are there? Ans. a) Turnkey Tenders
b) Limited Tenders c) Open Tenders d) Short Tenders e) Quotation Notice
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46. What is M.B. & its functions & uses Ans. It is called Measurement Book. It is used for recording the measurements of executed works before payment. This may for the road works, building works, Bridge & culvert works, stack measurements, supply of materials etc. This is very vital documents to the Govt. Department. For recording in details of the project before making any payment. The recording should be like projects name, Tender ………site location, name of Agency, date of commencement of works, date of completion, date of measurements, the item wise measurement records & the certificates for completion of the works as per terms and conditions of the tender specification. 47. What are the different Scales used for different Survey works as well as Mouza maps? Ans. Topographical Maps Town Survey 1 cm = 2.5 Km or 1/250000 2 cm = 1 Km or 1/50000 1 cm = 1 Km or 1/100000 4 cm = 1 Km or 1/25000 1 cm = 0.5 Km or 1/50000 10 cm = 1 Km or 1/10000 1 cm = 50 m or 1/5000
Large Scale Surveys & Layouts Preliminary or Sketch drawings dependent on the
Subject 1 cm = 20 m or 1/2000 1 cm = 5 m or 1/500 1 cm = 10 m or 1/1000 1 cm = 2 m or 1/200 1 cm = 5 m or 1/500 1 cm = 1 m or 1/100
Working drawings: Plans Elevations and Sections 1 cm = 2 m or 1/200 1 cm = 1 m or 1/100 1 cm = 0.5 m =1/50 Large Scale drawings General Details Enlarged Details 1 cm = 20 cm or 1/20 1 cm = 10 cm or 1/10 1 cm = 10 cm or 1/10 1 cm = 5 cm or 1/5 1 cm = 2.5 cm or ½.5 1 cm = 2 m or ½ 1 cm = 1 cm full size
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