Training-cum-Workshop of Field Engineers. 22 nd May to 4 th June, 2010. AIM OF THE TRAINING. Brief understanding on functioning our daily duty Social responsibility of building better world with number of hurdles. Conflict demands on the technical aspects.
22nd May to 4th June, 2010
Brief understanding on functioning our daily duty
Social responsibility of building better world with number of hurdles.
Conflict demands on the technical aspects.
Not feasible to use a single decision making process to solve every ethical dilemma,
At times it may force a technical personal to subjugate his or her self interest.
Procedural constraints and lack of awareness/exposure
Positive impacts so as to convince the field engineers in adopting such procedure at placed found effective.
The building estimate should contain the following
a site plan showing north point.
Approved neat drawing showing the plan, elevation and cross section to a suitable scale.
Specification and soil data
detailed specification of items of work as per codal provision such as IRC/IS specification
trial pit section of the soil/ soil test report.
f) Design particulars.
Detailed analysis of rates
j) In case of renovation, addition, alteration of the building, previous history of the case of work.GUIDELINES FOR PREPARATION OF ESTIMATE AND SUBMISSION FOR TECHNICAL SANCTION
The road estimate contains
history, designs, scope, rates, specifications, references, cost, mode of execution etc.
Detail estimate, abstract.
Plans, longitudinal and cross section and initial level.
Drawings of C.D. works.
In case of earth work relating to new roads/ widening of existing roads, renovation and excavation of a tank, the initial level of existing formation should be recorded.
Pre-measurement should be check measured by the higher authority before execution of the work
drawing showing the proposed final levels.
The code and practice prescribed by the I.R.C. and I.S. should be followed in general.
For lump-sum provisions for an item, the detailed estimate should be got approved.
References to the existing structures / sites should be indicated.
The estimate should be prepared as per the requirement of the project and not in piece meal basis.
Estimate shall not be splited up.
Sanctioned estimate to be entered in the register at G.P. level and at Block level assigning a number and date.
Earth : Earth from borrow area is utilized for road work suitable borrow area needs to be demarcated
Moorum : Good quality moorum needs to be selected
Metal & Chips : Metal & Chips of required size should be utilised.
Bitumen: As per specification should b utilises.
MATERIAL USE AND COMPREHENSHIVE STEPS
FOR ROAD WORK : (UP TO METALIC STANDARD )
Step-1 : Inspection of Quarries
Step-2 : Collection of Certificates about quality of source.
Step-3 : Collection of coarse, fine aggregates for GSB, WBM and binding materials from quarry.
Step-4 : Tests on coarse aggregate
Step-5 : Tests on GSB and binding materials (sand gravel admixture)
Step-6 : If all the materials are OK allow these for construction
Step-7: Remove all vegetation and other extraneous matter from sub grade-Lightly sprinkle with water if necessary – roll with two passes of 80 – 100 KN smooth wheel roller.
Step-8 : Construction of Shoulder for Lateral confinement with approved material.
Step-9 : GSB material to be spread and rolled with 80 – 100 KN roller after mechanical mixing (Manual mixing may be allowed if width of laying is not adequate for mechanical mixing) – Smooth wheeled roller up to 100 mm compacted thickness and vibratory roller when compacted thickness exceeds 100 mm. Rolling should commence from edges and progress towards center and each pass of the roller shall uniformly over 1/3rd of the track made in the preceding pass. The speed of the roller shall not exceed 5 Km./ hour.
Step-10 : Check cross fall (Camber) by template – spreading and rolling to continue till appropriate cross fall is maintained and compaction is achieved.
Step-11 : Carryout compaction test (98% compaction to be achieved)
Step-12 : Spread 23mm. course of screening (Grade – B) or coarse sand over the prepared sub-base (Optional).
Step-13 : Spreading of coarse aggregate over prepared sub-base uniformly and evenly.
Step-14 : Checking with templates. All high and low spots to be remedied by removing or adjusting aggregates.
Step-15 : Dry rolling and checking with straight edge.
Step-16 : Rolling with 80 – 100 KN roller shall begin from edges gradually progressing towards center except for super elevation portion, successive passes lapping uniformly preceding tracks by approximately one half width.
Step-17 : Rolling may be continued when aggregates are partially compacted with sufficient void space in them to permit application of screening.
Step-18 : However when screenings are not applied as in the case of crushed aggregates like brick metal, laterite and kankar, compaction may be continued until aggregate are thoroughly keyed.
Step-19 : During rolling slight sprinkling of water may be done.
Step-20 Rolling shall not be done when the sub-grade is soft or yielding or when it causes a wave like motion in the sub--grade or sub-base course.
Step-21 The rolled surface shall be rechecked transversely and longitudinally with templates and any irregularities corrected by loosening the surface, adding or removing necessary amount of aggregates and rolling until the entire surface conforms to the desired cross fall and grade.
Step-22 : In no case the screening shall be used to make up the depressions.
Step-23: Materials which get crushed excessively during compaction and become segregated shall be removed and replaced by suitable aggregates.
Step-24 : It shall be ensured that the shoulders are built up simultaneously along with WBM.
Step-25 : Application of screening materials spread uniformly in successive thin layers to completely fill the interstices.
Step-26 : Screening shall not be damp or wet at the time of application.
Step-27 : Dry rolling should be done while screenings are being spread so that vibrations of the roller cause them to settle into the voids of the coarse aggregates. This shall be accompanied by brooming.
Step-28 : The spreading, rolling and brooming of screenings shall be carried out in only such lengths of the road which can be completed in a day’s operation.
Step-29 : After dry rolling, the surface shall be copiously sprinkled with water, swept and roller.
Step-30 : Hand brooms shall be used to sweep the wet screenings into voids and to distribute.
Step-31 : The sprinkling, sweeping and rolling operations shall be continued with additional screenings applied a necessary until the coarse aggregates have been toughly keyed well bonded and firmly set in its full depth and grout has been formed of the screenings.
Step-32 : Care shall be taken to see that the sub-base or sub-grade does not get damaged due to addition of excessive quantities of water during construction.
Step-33 : After application of screenings, binding materials where required shall be applied in 2- 3 thin layers.
Step-34 : After final compaction of WBM course, the pavement shall be allowed to dry overnight and rolling and watering to continue till slurry after filling voids forms a wave ahead of wheels.
Step-35 : Next morning hungry sport shall be filled with screening slightly sprinkled with water if necessary and rolled.
Step-36 : No hauling traffic may be allowed to use the completed WBM course if in the opinion of the Engineer it would cause excessive damage to the surface.
Step-37 : The compacted WBM course should be allowed to completely dry and set before next pavement course is laid over it.
Step-38 : The sequence of construction shall be such that the construction of paved shoulder is none in layers each matching the thickness of adjoining pavement layer.
Step-39 : Only after a layer of pavement and corresponding layers in paved and earth shoulder portion have been laid and compacted the next layer of pavement and shoulder shall be taken up.
Proper survey of the alignment is to be done. The L.S. and C.S. should be drawn to proper scale and the final formation level is shown superimposing on it.
Detail drawing of C.D. work must be prepared with proper design at proper chainage accompanying the estimate.
The detailed estimate should accompany the report, abstract of estimate, quarry chart Lead chart, Analysis of Rate, L.S. and C.S. index map & Bar chart etc.
In case of bridges, the estimate must be accompanied with reports, L.S. and C.S. at 300m. U/S and D/S and at site showing HFL, OFL and LWL,plan, water way calculation ,trial pit and other hydraulic particulars. The report should also contain the detail designs, scopes, rates, specifications, references, cost and mode of execution etc
In case of metalling road, the required quantity and quality of materials is to be used.
R O A D S:
Earth work should be compacted with 10-12 T. roller exceeding 30 cm. in layer to achieve the maximum density.
M.S.B. should be consolidated by laying not exceeding 23 cm. in layer and compacted by the roller if necessary required amount of water is to be added uniformly.
The 1st coat metalling should be done with the locally available stone metal of compacted thickness of 4”.
The 2nd coat metalling should be done with black hard granite metal of compacted thickness of 3”.
The 2nd coat metalling should be covered up with B.T., otherwise, do not go for 2nd coat metalling.
Proper quality control measures has to be taken up by using quality materials and following IRC specification.
Provide drain wherever necessary. C.D. work and drain will be the 1st preference in case of road work.
Earth work computation should not be based on pit measurement
Don’t allow the work to be under compacted.
Don’t use moist screening material to fill-up the voids during metal consolidation
Don’t go for 2nd coat metalling where there is no provision of wearing course.
Estimate should not be splitted-up in any circumstances.
Work should not be taken-up without technically sanctioned and administratively approved estimate.
A bituminous road is damaged fast in high rainfall areas due to poor drainage conditions,
a gravel road becomes dusty, causing safety and health problems due to a cloud of dust raised by motorised traffic,
Problems of dust and wet weather damage to roads can be easily overcome by constructing a thin flexible concrete road using innovative technology at a cost lower than that of a bituminous pavement for equal traffic.GUIDELINE FOR THE CONCRETE PAVEMENT
Concrete roads have a large number of advantages over bituminious ones. These advantages include:
Long Maintenance-Free Life:
Gain in Traffic Speed:
Resistance to Weather, Oil Spils, etc.:
Economy in use of materials:
Use of Indigenous Materials:
Other Advantages: These include better reflectivity.CONCRETE PAVEMENT - ADVANTAGE
Concrete roads have a large number of advantages over bituminious ones. These advantages include:
Concrete roads, however, have one disadvantage vis-a-vas bituminious ones, in that they are initially costlier to construct.
with the price of bitumen going up steadily, and the use of fly ash (available free from power plants) in making concrete mixes for pavements now being accepted, the relative cost of these two types of pavements could become quite comparable.
When life-cycle costs are considered (as recommended by the BIS, for all competing technologies), concrete pavements with their long life and negligible maintenance, come out invariably superior to bituminious ones.
As regards the economic costs to the country, fuel saving and environmental friendliness make concrete roads a far superior choice over bituminous ones.CONCRETE PAVEMENT - ADVANTAGE
care must be taken to utilise fresh cement instead of old cement.
Freshness can be checked in the bag itself since year and month clearly indicated in the bag.
machine stitched is needed to be checked.
To ascertain the adulteration in cement if pinch of cement is dropped in water, it will float in the water due to its super fineness or else it will sink immediately.
Type of Cement:
i. Ordinary Portland Cement IS:269
ii. Rapid Hardening Portland Cement IS:8041
iii. Portland Slag Cement IS:455
iv. High strength ordinary Portland cement IS:8112
v. Portland Pozzolana cement IS:1489
Note: Use of Portland pozzolana cement may be permitted only in plain concrete members.
CONCRETE PAVEMENT : MATERIAL REQUIRED
Even though, basic requirement of water in cement mixture is very less but for workability the water is added more. For example: Concrete M15, the water cement ratio is approximately 42%.
Since, the water cement ratio serves as a yardstick for obtaining concrete of desired strength the less the water greater the strength. But if more water is utilised, it results excessive void, honey combs thereby reducing density, strength and durability. So it must be prevented during execution.
Coarse aggregates: (to be utilised as per approved specification)
Clean, hard, strong, dense, non-porous and durable pieces of crushed stone, crushed gravel, natural gravel or a suitable combination.
Shall not contain pieces of disintegrated stones, soft, flaky elongated particles, salt, alkali, vegetable matte or other deleterious materials.
Aggregate should not contain more than 5% of SO3.
Use of higher size aggregate may lead to segregation.
Aggregate impact value not exceeding 30% to reduce degradation of the aggregates by crushing.
The maximum size of coarse aggregate shall not exceed 25 mm. for pavement concrete.
No water absorption more than 2%.
If the aggregates are not free from dirt, may be washed and drained for at least 72 hours.
Hard, strong, durable clean particles of natural sand, crushed stone or crushed gravel.
Shall not contain dust, lumps, soft or flaky particles , mica and other deleterious materials in such quantities as would reduce the strength or durability of concrete.
Clean natural sand or crushed stone.
Water used for mixing and curing shall be clean and free from injurious amount of oils, acids, alkalis, salts, sugar organic materials.
Potable water is satisfactory for mixing concrete.
The maximum water cement ratio shall be 0.50.
Measuring cement by weight.
Fine and coarse aggregates shall be by volume or by equivalent weight.
All concrete shall be machine mixed.
Until it is of even colour and uniform consistency throughout
Done for two minutes.
Mixed for immediate use.
Initially set cement shall not be used.
Initial set of ordinary Portland cement is 30 minutes after mixing.
Shall be transported as rapidly as practicable.
Prevent the segregation or loss of the ingredients.
Normally shall be completed within 30 minutes.
Avoid re-handling or flowing.
Placing and compacting concrete:
Shall be placed before setting has commenced
Not be subsequently disturbed.
Shall be so placed as to avoid segregation.
Concrete shall not be dropped freely from a height of more than 2 metre.
Shall be thoroughly compacted.
Vibrators shall be used.
Vibrator should be kept until air bubbles cease escaping from the surface and withdrawn slowly so that no hole is left.
Vibrators shall be inserted about 1.5 times the radius of the area visibly affected by vibration.
Presence of 5% void reduce the strength by 30% and 10% void will reduce 60%
Concrete up to construction joints.
Shall be pre-determined (Length – 4.5m., Width – 3.5 m.)
Have sufficient lateral rigidity to prevent displacement or bulging.
Avoid dislodgement of coarse aggregates.
Hardened surface can be resumed after thoroughly hacked, swept clean, wetted and covered with a layer or neat cement grout.
13mm thick layer mixed in same proportion in concrete
Use chairs to ensure cover.
Curing and protection of concrete:
Kept constantly wet for a minimum period of 14 (fourteen) days.
Water be applied on unformed surface.
Concrete shall be kept constantly wet by ponding or covered with a layer of sacking, canvas, hessian or a similar absorbent.
After placing concrete shall be protected from harmful effects of sunrays, drying winds, cold, running water, shocks, vibrators, traffic including construction traffic etc
Also, affect regarding the flow if constructed in the catchment flow such as WHS
It helps irrigation. water supply to cattle, fish ,plantation
It increases the ground water table
It should be suitably finalised
In the depression and valley
For irrigation Purpose
The site should be such that largest storage can be made with least amount earth
Gravity out let should be provided
COMPONENTS OF FARM POND:
FARM POND/ NEW POND
The area needs to be demarcated where the work is to be taken up
Also, the area needs to be demarcated where the earth is to be desposed of after excavation.
The area needs to be marked with pegs on four site at a interval of 10-20 ft. so that by ting with rope on the opposite place, the level (height) of execution at a particular point can be determined.
The earth work executed should be breaked to minimum of 4 cm. size and to be laid with proper dressing as detailed given in the initial stage.
Renovation of old pond:
The area needs to be demarcated for execution and dumping the earth.
The pegs at an interval of 10 - 20 ft. on four sides should be placed so that the level with the height of execution can be calculated by tying rope in the peg on both side before execution as well as after execution. The peg should be placed beyond the execution area.
FARM POND/ NEW POND
The measurement can be done either through pit or through level section.
For pit measurement, the pits should be invariably of a standard size i.e. 10ft.x10ftx1ft.
The height can be 1ft., 2ft. and 3ft and it can be further multiplied to evaluate the quantities.
The pit should be numbered for each individual or group to avoid any immediate error in assessing the quantities. These pits can be measured for both side of the road work.
As per level section (grid), the area where execution to be made needs to be divided/demarcated in longitudinal and transverse direction at a standard interval with pegging thereof.
In the road alignment, the quantity can be ascertained on this fashion so as to compare the quantity as per pit measurement.
Immediate measurement the height can be achieved though the witness (sakhi) kept by the labourers on the grid point for which the tying of rope in a frequent manner can not be required.
Most of the areas are irrespective of black cotton soil or ordinary soil of swelling nature which causes foundation failure and also the swelling type of testing is very much simple and less costly with involvement of only water and kerosene.
If the swelling type of soil is available then the said soil should be replaced by course sand up to 1.5 D( where D is the width of the foundation) with provision of ordinary foundation which prevents shear crack.
Whenever the soil beyond 1.5 D is very poor in nature with low SBC such as marine soil, such deep foundation like pile is to be adopted.
Most of the time, the carriage contractor collects sand with silt as ingredient causing damage to the building as sand mix silt/ clay cracks and termite in the building which should be judiciously checked.
TIPS ON BUILDING WORKS
1st class bricks to be used in the works conforming to the requirements of I.S:1077.
Strength of individual brick shall not be less than 7 Mpa (70kg/cm2)
Size shall be according to the local practice with tolerance of + 5%.
Bricks shall be free from cracks, organic matters, flaw and nodules of free lime.
Brick shall have rectangular faces with sharp corners.
Emit clear ringing sound when struck
Bricks of 190 mm x 90 mm x 90 mm or 230 mm x 110 mm x 70 mm shall be preferred.
Water absorption up to 20% by wt.
Bricks shall be stacked in regular tiers as they are unloaded to minimize breakage and defacement.
Bricks supply should be so arranged that at least two days requirements of Bricks are available at site at any time.
Bricks selected for use in different types shall be stacked separately.
All bricks shall be thoroughly soaked in water for a minimum period of one hour before use.
Soaked bricks shall be removed from the tank sufficiently in advance so that they are skin dry at the time of actual laying.
All bricks shall be laid in English Bond even and true to line.
All joints should be accurately laid. Joints in the successive courses of the brick work shall be broken and the length of lap between the joints of the stretcher course with the header course shall not be less than one fourth of the length of the brick.
Brick bats or cut bricks shall not be used except to obtain dimension of different course.
All brick shall be laid with frog up on a full bed of mortar.
When laying bricks shall be slightly pressed so that the mortars gets in to all the surface pores of bricks to ensure proper adhesion.
All joints shall be properly flushed and packed with mortar so that no hollow spaces left.
Brick works shall be laid in uniform layer, true to plumb or in specified batter.
No part of brick work shall rise more than one metre to avoid unequal settlement and improper jointing.
Work shall be raked back to the bond and not toothed at an angle not steeper than 45º
Masonry work shall not be started earlier than 48 hrs. of casting of foundation Block.
Foundation Block shall be thoroughly hacked, cleaned, wetted and a layer of not less than 12 mm of mortar shall be spread to prepare the surface on which bricks will be laid.
In case of Rock, the surface shall be thoroughly cleaned and levelling course of M10 grade with minimum average thickness of 150 mm shall be provided before laying the layer of mortar.
In case of jointing with old masonry, the exposed joining surface shall be cleaned of all loose materials, roughened and wetted with cement sherry to effect the best possible bond with the new work.
All brick work shall be properly marked indicating the date of construction for keeping watch for proper curing.
Masonry work in cement mortar shall be kept constantly moist on all faces for a minimum period of seven days.
The work with mortar which has become dry, white or powdery due to neglect or curing shall be pulled down and rebuilt.
If any stain appears on the surface during watering shall be removed.
Mortar shall be mixed such quantity as required for immediate use.
As a general guide, not more than half bag of cement shall be mixed at a time if one mason is engaged.
The mix which has developed initial set shall not be used in the works.
Retempering is permitted within initial setting time of 30 minutes.
Cement mortar unused for more than 30 minutes after addition of water shall be rejected and removed from the site.
Site for the project is to be selected and proper survey is done if necessary
After survey to the site selected, the drawing i.e. plan, elevation and section should be prepared to a proper scale indicating the north point.
The S.B.C. of the soil should be determined.
Estimate should be prepared for the whole project which should contain a report, detailed estimate, quarry
Chart, lead chart and analysis of rates.
Technical sanction and Administrative approval should be accorded from the competent authority.
Structural components of the buildings should be properly designed and care should be taken in case of bad nature of soil.
Care should be taken for execution of concrete work and curing should be done for 28 days.
DO’S AND DONOT FOR BUILDING
During placement of the reinforcement, attention should be given for proper laying of the reinforcement at the support where there is (-ve) bending moment. Proper cover to the reinforcement should also be provided as per codal procedure.
Before taking-up the lintel, Chaija and roof slab, the centering and shuttering must be checked properly.
Proper quality materials should be used for the work confirming to I.R.C/ I.S. and Orissa Standard Specification.
Prescribed water cement ratio should be followed.
Bearing plaster and tarpaper should be provided on the top of the wall before casting of the slab.
The estimate should contain the material component and labour component to derive food grain component and their recovery.
In case of renovation, addition and alteration of the building, previous data of the work should also be mentioned in the report.
DO’S AND DONOT FOR BUILDING