SPECIFICATION FOR WORKS



SPECIFICATION FOR WORKS

EARTH WORK:-

Earth unless otherwise mentioned specifically, means all kinds of soil, sand, slush, silt dry or wet and hard or soft rock.

The rate of excavation of earth in all items will include the cost of nicking out lines, putting profiles, cutting and removing of thick and thorny jungles, roots of trees and stumps of all sizes, trees upto 0.3 metre girth, from the site of work as directed by the Engineer-in-Charge.Site of work will include both the site of excavation and the site for depositing the earth and throwing/laying of the spoils. During the excavation, the natural drainage of the area shall be maintained. The rate in all relevant items will also include dewatering and making arrangement for disposal of bailed water. Clearance of silt and slush by using bucket or pan if necessary, removal of water hyacinth and burning them to ashes and weeds, carcasses, organic matter etc.

The earthwork shall be classified under the following categories and  measured separately for  each category:

All kind of soils:

Generally any strata, such as sand, gravel, loam, clay, mud,  black cotton, moorum, shingle, river  or nallah bed boulders, siding of roads, paths etc. and hard core, macadam surface of any description (water bound, grouted tarmac etc.), lime concrete, mud concrete and their mixtures which for excavation yields to application of picks, shovels, jumper, sacrifiers, ripper and other manual digging implements.

Local soil or sand mixed with shingles:-

This item will include soils having shingles upto 10 cm size more than 10  %  as  constituents but  will not contain more than 5 % of boulder of size above 10 cm (by eye estimation). This may be excavated by spades.

Local soil or sand mixed with shingles and boulders:-

This item will include soils having boulders of size above 10 cm upto  20 cm  by  more than 5  %  upto 20 % (by eye estimation). This cannot be excavated by  spades only, pick axes have to  be  used.

Ordinary rock:-

Generally any rock which can be excavated by splitting with crow bars or picks and does not require blasting, wedging or similar means for excavation such as lime stone, sand stone, hard laterite, hard conglomerate and un-reinforced cement concrete below ground level.If required light blasting may be resorted to for loosening the materials butthis will not in any way entitle the material to be classified as ‘Hard rock’.

Soft weathered rock/soft laterite:-

In case of soft weathered rock / soft laterite, it can be excavated by pick axes and come out in small pieces, undisturbed 8 cm cube of such rock cannot be broken by hand pressure but will disintegrate into small particles by hitting with 1 kg hammer.

Hard rock:-

In case of hard weathered rock/hard laterite, it will consist of hard boulder above 80 Kg or strata of hard rock which may require blasting for removal. It has to be broken into pieces of size below 50 Kg for which no extra payment will be made. The boulders of size between 30 Kg to 50 Kg will have to be stacked separately for which separate payment for stacking will be made with deduction of void. For blasting, the contractor must possess a license for using and storing of gelatin or gun powder. A properly trained & licensed fireman shall be engaged for handling of explosives & blasting. Special  care is to be taken for blasting near homesteads. In this connection, instruction of the Chief Mining Engineer is to be followed regarding blasting operation. Generally any rock or boulder for the excavation of which blasting is required such as quartzite, granite, basalt, reinforced cement concrete (reinforcement to be cut through but not separated from concrete) below ground level and the like.

Hard rock (blasting prohibited):-

Hard rock requiring blasting as described under (F) but where the blasting is prohibited for any reason and excavation has to be carried out by chiseling, wedging, use of rock hammers and cutters or any other agreed method.

Excavation from borrowpits:-

This item is intended for making embankment, repairing or strengthening old embankments, putting and removing long bundhs, partition bundhs and cross bundhs, filling poly or gunny bags etc. The earth has to be taken from borrowpits either from the river/channel side subject to tidal inundation during the working period or from the countryside. The sides and location of borrowpits are to be selected strictly as per instruction given by the Engineer-in-charge and in all types of borrowpits excavations, keeping of proper witness is mandatory on the part of the contractors. The earth has to be deposited in layers not exceeding 25 cm in the profile in proper slope at required levels.

The clods will have to be broken and the top, side slopes will have to be  roughly dressed to the designed profile. The  witnesses of borrowpits will have to be removed by  the contractor   at his own cost and laid in the profile of the embankment after the check measurement, failing which, the contactor will be liable for accepting deduction of 10% in the measurement. The contractor has to fill up the borrowpits if excavated in homestead, road and other undesirable areas, at his own cost.

    1. Excavation in new drainage channel or re-excavation/widening of existing drainage channel above ruling water level or re-sectioning of channels in excess of the design section

This item would be provided for excavation in drainage channels and widening  above water level where no cross bundh need to be constructed. During re-excavation of drainage channel involving re-sectioning, where cross bundhs, long bundhs, partition bundhs need to be erected, the extent of earthwork beyond design section (a trapezoid consisting of base width as the  designed bed width and divergent  sides are designed side  slope) will also be  classified in  this item and the remaining earthwork within the design section will be classified as silt. The excavation has to be made in proper slope and at required levels and spoils are to be  deposited so as to make marginal embankment in proper place as directed by the Engineer-in-charge on both banks including rough dressing.

  1.  

Silt Clearance of drainage channels including sludge and slush but excluding slush mixed with industrial wastes, municipal garbage, carcasses, khatal effluents etc.

This item is intended for drainage channels mainly in rural areas as well as in the border line of semi-urban areas i.e. beyond the periphery of Corporation/municipal or industrial areas, where not much quantity of municipal garbage and industrial wastes and other contamination are normally encountered. However, in case of any confusion/dispute  regarding  selection  of zone of applicability, the decision of the Superintending Engineer will be final and binding. Normally major portion of the silt may be excavated by shovel, however the item also includes initial silt clearance work by  pan or bucket, if  necessary. The item also includes cost of removal of water hyacinth, thick and thorny jungles upto 30 cm girth, compact mass formed due to formation of water hyacinth etc. The measurement will be taken on the basis of pre and post level sections unless mentioned otherwise. Deposit of excavated material will be  generally  as  per 1.3 above. If sufficientGovernment land is  not available on channel bank,  the extra quantity of excavated material after making the marginal embankment on both banks may be  disposed  off subject to instruction of the Engineer-in-charge for which separate payment will be made, however, till such time, the excavated material shall be stored and stacked properly, so that it does not fall back in the channel, not it shall create hindrance to traffic movement on channel bank, fall in the private land on countryside of embankment and  thereby  damage  crop  or  private properties. The rate includes cost of putting  and  removing intermediate cross  bundhs but excludes the cost of putting and removing long bundhs, end cross bundhs and partition bundhs for sealing inlets etc. However, Engineer-in-charge reserves the right to deduct a maximum of 20%, as a penal measure, from the total amount of the respective items of silt clearance for unsatisfactory removal of cross bundhs, long bundhs, partition bundhs, sealing inlets etc.

The item has been further classified in three categories in regard to modalities for bailing out of water.

    1.  

For channels containing practically no upland dry weather flow as normally encountered in many drainage channels in rural area.

For drainage channels containing some dry weather flow but where suitable arrangement of diversion can be made  through adjoining existing drainage channels, low lying drainage pockets by merely constructing cross bundhs/partition bundhs at the selective location and/or excavating short length diversion channel.

For drainage channels containing dry weather flow but diversion through other channels or in drainage pockets are not feasible and the running water cannot be bailed out  in  the  adjoining land and has to be managed either by  pumping in  alternate segmented pockets formed within the drainage channels to suit segmental silt clearance or through longitudinal gutter drains/channels formed within the channel.

While the earthwork and ancillary  works required for forming the suitable arrangement  of diversion (excluding the intermediate cross bundhs formed across the channel) will be paid extra, the rate of earthwork in silt clearance includes, in all cases, cost of arrangement for bailing out of stagnant water, water deposited for subsequent rainfall, running water, seepage water coming from soil underneath etc.

  1.  

Silt Clearance of drainage channels including sludge and slushmixed with all sorts of industrial waste, municipal garbage, carcasses, dead bodies, polypacks, small khatal effluents etc.

This item is intended for drainage channels in thickly populated semi-urban areas, market areas and in fully urban areas such as within and contiguous to the periphery of corporation / municipal / industrial areas. As already stated in 1.4 above, the decision of the Superintending Engineer will be final and binding regarding zone of  applicability. The  rate  includes engagement of mathor labours, silt clearance work by pan or bucket etc. The item also includes  cost  of  removal of water hyacinth, polypacks, jungles, compact or semi-compact mass formed due to water hyacinth, removal of khatal, latrines, carcasses, night soil, small to  medium  khatal  effluents, industrial effluents etc. Measurement will be taken on the basis of pre and post level section unless specifically mentioned otherwise. Deposit of excavated materials will have to be made on bank top, countryside of embankment or as directed by the Engineer-in-charge. Extra material may be disposed otherwise, as instructed by the Engineer-ln-charge, it shall be ensured that the slushy material, either during temporary or permanent  storing within  Government land or during disposal,  shall be  barricaded properly so  as not to  cause any hindrance to traffic flow   or damage to public properties or pose any health hazard. The rate includes the cost of putting and removing intermediate cross bundhs, but excludes the cost of putting and removing long bundhs, end cross bundhs, partition bundhs, sealing inlets etc. However, the Engineer-in-charge reserves the right to deduct a maximum of 20%, as  a  penal measure, from the total amount of   the respective items of silt clearance for unsatisfactory removal of cross bundhs, long bundhs, partition bundhs, sealing inlets etc.

The item has further been classified in two categories in  regard to  modalities for bailing out water. Since drainage channels in urban areas always contain dry weather flow, category 1.4.2 and 1.4.3 as enumerated in the foregoing para of 1.4 will be applicable. As already mentioned, the cost of arrangement for bailing out of all sorts of water including stagnant water, rainfall deposit, sub-soil seepage, running water etc., are included in this item.

Closing Ghoges:-

The earth has to be relaid by puddling with water and ramming in layer  not  exceeding 25  cm.  Only one measurement (that of cutting) will be paid  for. The opening and closing  shall  be  done  as per time schedule directed by the Engineer-in-charge.

Breach Closing:-

The work is to be done in submerged areas of a tidal river. The closure work shall have to be maintained and guarded with all materials and labours round the clock by the contractor at  his own cost along with arrangements for sufficient lights at night etc. till the work is handed over to the Department.

The earth has to be taken from borrow pits subject to tidal inundation during the working period. The size and location of borrow pits are to be strictly  followed  as  per  the  instruction given by the Engineer-in-charge and in all cases, keeping up of a central witness is mandatory on the part of the contractor. The earth has to be deposited in layers not exceeding 25 cm in the  profile and in proper slope and duly puddled. The clods have to be broken and  the  top, side  slopes have to be roughly dressed to designed profiles.

The measurement for earthwork for the breach closing work will be taken by pit measurement or section measurement as the case may be and as per direction of the Engineer-in-charge, whose decision is final.

On completion of breach closing, 10 per cent voids will be deducted from gross measurement, if measurement is done by section measurement of banks.

The payment of earthwork will be made after handing over of finished section to the Department. No payment will be made for guarding any part of work before handing over of the whole closure. Additional expenditure, if any, to be incurred due to the delay  in  completion, will be recovered from the contractor. The contractor shall not be entitled to  claim  any  compensation for loss of labour and materials for the closure work prior to handing over to the department.

General Note on Measurement of Earthwork:-

Borrowpits for making, repairing and strengthening embankments and  breach  closing,  putting and removal of cross bundhs will generally be measured by pit measurements unless otherwise stated. Measurement will be taken by pre and post work section in silt clearance, excavation or re-excavation of drainage channels etc. unless specifically mentioned. No deduction of voids will be made in silt clearance and excavation or re-excavation of drainage channel, but 10 per  cent  void will be deducted from gross section in case of finished banking works (if sectional measurement is adopted), stacks of earth etc. A deduction of 10 per cent will also be made until witnesses in borrowpits are removed. A maximum amount of 20 per cent measurement will be deducted from respective item of silt clearance for non-removal of cross bundhs, long bundhs, sealing of inlets etc. in drainage channel. Prework section will be taken before the  commencement of work and post work section will be taken after the work is completed prior to handing over to the Department unless otherwise mentioned specifically. The profile has to be provided at every 30 metre approximately unless mentioned otherwise, however bed width and bed level may be checked at random. The contractor shall arrange for peg, bamboo, coir string and labours during measurement process.

For Making new embankment (Ring bundh/Retired embankment etc.):

Work is to be executed on the basis of pre work & post work level sections. Deductions for voids in section measurements will be made as follows: Pre-work sections shall invariably be taken before the commencement of carted/carried earth work. Necessary deduction  will  be  made from pit measurement if there is wastage of excavated materials.

No deduction for voids in section measurements would be made,  when  the measurements are done after 2nd monsoon. Profile is to be fixed with proper shrinkage allowance.

The laying of excavated earth shall be done in layers not exceeding 25 cm. and the clods will have to be broken. Foreign materials such as roots & branches of trees, drift, timbers, bushy jungles, grasses etc. mixed with excavated earth from borrow pits shall not be laid in the bank. The base of embankment shall be ploughed before laying first layer. The rate of excavation includes all these operation. The excavation of canal, canal banks, flood embankment etc. will have to be made as per profile which will have to be  provided by  the Contractor at his own cost  at every 30 metre approximately. Necessary dug belling showing the lines of  embankment or spoil bank & edge of cutting canal or borrow area will have to be done by the Contractor which  has been included in the rates of excavation.

 

 

Nature of Carriage

 

 

Period of Measurement

Percentage of Voids be deducted from gross measurement

 

 

Remarks

By head load

Upto 31 July.

10

Within 1st year's first half monsoon.

-Do-

Between 1 August and 15th October

5

Within first year's second half monsoon.

-Do-

Between 16th October and next year's 15th Oct.

3

After first year's full monsoon,

-Do-

After 16th October of next year.

Nil

After two year's full monsoon.

By truck or tractor or cart.

Upto 31st July

4

Within first year's first half monsoon

-Do-

Between 1st August and 15th Oct.

3

Within first year's Second monsoon.

-Do-

Between 16th October and next year's 15th Oct.

2

After first year's full monsoon,

-Do-

After 16th October of next year.

Nil

After two year's full monsoon.

Lead & Lift Measurement:-

The measurement of lead and lift will be generally horizontal and vertical distance respectively between centers of gravity of the excavated zone and of the spoil bank/embankment

Lift Measurement:-

The lift may be calculated based on the under mentioned consideration to avoid rigorous calculation of centers of gravity.

In case of new work:-

The vertical distance of 0.375 times the height of spoil bank from the  ground  level  plus  0.40 times the depth of canal excavated (0.5 times the depth in case of borrow pits) from the same ground level.

In case of old work:-

Total lift shall be taken as difference in height between level of cutting edge of slope on or near bank top and existing average prework level of the channel bounded between cutting edges of slope plus 0.4 times average depth of excavation (obtained by deducting average prework level from designed bed level of the channel) plus difference in height between existing highest ban k level (average of highest value of left and right bank if earth is deposited on both banks) and  cutting edge of slope, plus 0.375 times the height of newly formed spoil bank, if any, (height of spoil bank being measured from existing highest bank level as mentioned).

Lead Measurement:-

The lead (head lead generally upto 300 metre) will be taken as the  horizontal distance as crow flies between the centre of excavated zone (irrespective of depth of cutting) and the centre of  spoil bank. All distances shall be measured over the shortest practical route and not necessarily the route actually taken. Route other than shortest practical route may be considered in cases of unavoidable circumstances and approved by the Engineer-in-charge along  with  reasons  in  writing.

The distance between the centre of the excavated zone and of the centre of spoil bank in carted earth (generally beyond 500 metre) and the boated earth shall be measured on the basis of shortest practicable route as decided by the Engineer-in-charge.

No payment will be made for earthwork done from any area not identified by the Engineer-in-charge. Foreign materials such as roots and branches of trees, bushy jungles, water hyacinth etc. mixed with excavated earth from borrow pits shall not be laid in the bank.  The  profile has to be provided at every 30 metre approximately, at  contractor’s cost including supply  of peg, bamboo, coir sting and labour.  Necessary dug-belling showing the lines of  embankment  or spoil bank and edge of cutting along the canal or the borrow areas will have to be done by the contractor, the cost of which is included in the rates of excavation and no extra payment shall be claimed.

No additional expenditure incurred due to the delay in completion of the work in silt clearance, re-excavation of channel or breach closing shall be  claimed by  the contractor. The contractor shall not be entitled to any compensation for loss of labour or materials due to breach of cross bundhs or closure of work.

No extra payment will be made to the contractor for payment of Royalty or Cess in purchasing earth, because such considerations have already been made in appropriate items.

Excavation of Foundation and Filling up Trenches:-

Foundation, when excavated to the level shown in the drawing, will be shown to the Engineer-in-charge and if on account of some reason, he decides to go deeper, the contractor shall excavate further as per requirement. Base width of the trench, shall not, generally be more than the width of the bottom most part of the structure, adequate side slopes, depending on soil encountered, may be provided to ensure stability of the slope. No claim regarding excavation in excess of base width of structures for providing working space, shall be entertained. The foundation trench has to be kept dry by  providing suitable arrangement of bailing out of all sorts of water, cost of which is included in the item. However, if  soil investigation report indicates that  in case of very permeable sub-soil like silt or sand, substantial sub-soil seepage and sand blowing would occur and well point dewatering or similar method for lowering the ground water table is required to be taken up, the same shall be paid extra. Analysis of rate for such item may be done and got  approved by the Superintending Engineer. The  rate includes clearance of  silt and slush  by using pan and bucket if necessary, removal of water hyacinth, jungles up to  30  cm  girth, organic matter, municipal garbage etc, unless otherwise stated specifically. In no case, shall the foundation concrete or soling be laid prior to receiving order to that effect from the Engineer-in-charge or his authorized representative.

Excavation shall include throwing the excavated earth atleast 1.50 m or half the depth of excavation, whichever is more, clear of the edge, if not otherwise instructed by the Engineer-in-charge.

The excavated areas around the foundation of structures are to be  filled up  properly to  the required levels with earth obtained from excavation or other materials as directed, well rammed with water and consolidated in layers of required thickness. The  quantity for this item will be measured on the basis of quantity of excavation paid, less the volume occupied by the structure in foundation.

Note:

In case, due to paucity of space or other reasons, straight  excavation is  required to  be  carried  out and shoring might be required for loose earth/sandy or silt soil  or  deep  excavation  is required in clayey soil, the rate and  specification of such work may  be  taken from the  Schedule of rates of P.W.D.

Removal of Water Hyacinth:-

The item includes removal of water hyacinth, weeds, floating garbage etc. in rural and urban  areas. The rate also includes cost of burning the water hyacinth on channel bank, when dry or removing outside Government land, either in the countryside of the embankment or in  vacant  land / dumping grounds in conformity with municipal rules, so that the materials either during temporary or permanent storing / deposition or during disposal shall not cause any hindrance to traffic or pose any health hazard. In no circumstances, the water hyacinth shall  be  allowed to  push beyond working zone in the downstream reach. Payment will be made on the basis of stack measurement after deducting voids @40%. No payment shall be made for water hyacinth deposited on the water side slope of the channel. In urban  municipal  areas,  sometimes  it  is found that for some length in the upstream of the bridges (wooden, bamboo or multi span concrete bridges) and in front of the pump houses or near market  places  or  in  areas  where khatal effluents are directly disposed in channels, semi compact masses are formed due to deep rooted water hyacinth along with municipal garbage, polypacks, khatal effluents, long grasses    etc. Rate of removal of such type of semi compact mass is not included in the  instant  item and may suitably be analyzed and got approved by the Superintending Engineer.

ANTIQUITIES AND USEFUL MATERIALS:-

Any finds of archaeological interest such as relics of antiquity, coins, fossils or other

Articles of value shall be delivered to the Engineer-in-charge and shall be the property of the  Government.

PROTECTIONS:

Excavation where directed by the Engineer-in-charge shall be securely barricaded and provided With proper caution signs, conspicuously displayed during the day and properly illuminated with red lights and/or written caution messages using fluorescent reflective paint as directed by Engineer in charge during the night to avoid accident.

The Contractor shall take adequate protective measures to see that the excavation operations do not damage the adjoining structures or dislocate the services. Water supply pipes, sluice valve chambers, sewerage pipes, manholes, drainage pipes and chambers, communication  cables, power supply cables etc. met within the course of excavation shall be properly supported and adequately protected, so that these services remain functional. However, if any service  is  damaged during excavation shall be restored in reasonable time.

Excavation shall not be carried out below the foundation level of the adjacent buildings until underpinning; shoring etc. is done as per the direction of the Engineer-in-charge for which payment shall be made separately.

Any damages done by the contractor to any existing work shall be made good by him at his own cost. Existing drains pipes, culverts, over head wires, water supply lines and similar servicesencountered during the course of execution shall be protected against damage by the contractor. The contractor shall not store material or otherwise occupy any part of the site in manner likely to hinder the operations of such services.

PROTECTIVE WORKS :-

Bullah Piling Work:

Bullah piles shall be strong, straight and free from knots, holes and cracks. No joints  in  bullah piling is admissible except written permission from  the  Engineer-in-charge.  Extra  length required for lapping and cost of supplying of nuts, bolts and rings will not be paid  for.  The diameter of piles will be measured at a distance of 1.50metrefrom the thicker end. The driving of bullah piles will be done either in the river / channel bank or in the bed of the river /  channel  under tidal condition and stagnant or flowing condition of river etc. in  all kinds of soil. The rate     of supply is inclusive of sharpening the thinner end of the bullah and length shall be measured after sharpening shaping, and numbering. The piles will have to be  driven  vertically  true  to  plumb along the alignment and upto required depth. The top of piles will have to be maintained more or less in the same level or as directed. The rate of driving is inclusive of hire charges of hoisting and driving arrangement, staging, scaffolding, floating arrangement like boats  etc.  Driven length shall be measured by  deducting the  exposed length from the  supply  length.The rate is inclusive of shaping of toe, protection of head and hire charges of necessary driving appliances and tools, boat or pontoon and scaffolding. No payment will be made for exposed portion of bullah. No pile shoe will be used if the driving is possible upto the required depth without the shoe and the decision of the Engineer-in-Charge shall be final in this respect.

During taking out bullah piling, payment shall be made over previously considered driven length only. The rate of taking out includes hire charges of scaffolding, chain pulley block, rope drum, floating arrangement and all other accessories.

Bamboo Piling Work:-

The bamboos shall be of thick & almost solid variety, fully matured and as  straight as  possible. The diameter shall not be less than 5 cm. The diameter will be  measured at  half length of each pin or bamboo as the case may be.

Driving shall be done reasonably true to plumb to the required depth by hammer, mallet or monkey as necessary under stagnant or flowing stream. All bamboos split up or damaged during driving shall be removed & replaced at contractor's own cost.

The runners, ties or struts shall be fixed by 16 SWG G.I. wire at every joint and nailed at every 2 metre.

Pitching Works:-

Before the pitching work is undertaken, the river bank shall be cut and dressed to proper slope. Pitching shall not be laid on made up earth except where unavoidable. In such cases, the earth shall be watered well, rammed and consolidated before hand.

Empty cement polythene bags:

Empty second hand cement polythene bags (capacity 50 kg)  filled  up  with  locally available sand / silt / loamy soil and sewing after filling may be used as a purely temporary measure, on riverside side slopes of newly constructed embankment, particularly when  such slopes are built up by filling of earth and such palliative pitching works are scheduled to  be replaced by suitable rigid or flexible pitching of permanent nature, e.g. brick block, dry brick, cement concrete, boulder, geobags, etc., immediately after passing of one monsoon season.

High-density Polyethylene (HDPE) bags:

High-density Polyethylene (HDPE) bags conforming to IS: 14252:2015, filled up with sand / silt / loamy soil and machine stitched after filling may be used for pitching as a semi-permanent measure, on riverside side slopes of river / channel bank or embankment, above LWL in the following cases:

Scour hole below LWL has been filled up by dumping nylon crated bags or other suitable materials, and the resultant composite mass used for filling would be required to be kept after observation for at least more than a year, before stabilization. Upon stabilization of the underwater mass, such HDPE bag pitching, if found disintegrated on a large scale after 4  to  5  years due to UV radiation or other reasons, may be replaced by other suitable rigid / flexible pitching of more durable nature. In case of minor disintegration of individual bags, these may be suitably replaced by new HDPE bags.

The pitching work is generally subjected to low / moderate flow velocity as per standard calculation, not exceeding 2.5 meters, and/or access condition at worksite may not be conducive for deployment of heavy machinery and equipment, and/or the  demographic  and  socio-economic conditions prevailing in the area to be protected otherwise justify  use  of  the HDPE bags, instead of adopting cost prohibitive rigid protective measures of more  durable nature.

Geobags:

Geobags / composite geobags manufactured using UV stabilized woven / combination of woven and non-woven geotextile films may be used when:

Flow velocity is  relatively high, in  excess of 2.5 meters as  generally found in many rivers of North Bengal thereby requiring heavier mass of individual units, which could  easily  be  achieved by filling up geobags with sand / silt / loamy soil obtained from riverbed or river berm lands.

Underwater scouring has fully been stopped and the combined mass below LWL used for filling up scour holes has been stabilized.

Prevailing wave action calls for heavier mass of individual units of pitching and  deployment of required machinery at site, like crane can be made easily.

Cost competitiveness of geobags including cost of supply, filling and laying in position, compared to the corresponding cost of conventional rigid pitching materials, has  been established.

Applicability of different types of flexible protection under  different  site  conditions stated in Para 2.3.1.1 to 2.3.1.3 above are purely suggestive and may be used only as a primary guidance, as these items are relatively new and do not have much past reference of uses. The Engineer-in-charge is to carefully consider all the relevant aspects,  including  design,  construction, maintenance, durability and economics as per codal provisions  or  sound  engineering practices, before making the final selection of the particular type of flexible pitching. Assistance of the Design Wing may be solicited, if required.”

Rigid Pitching:-

Brick Pitching:-

Brick pitching shall be made with 1st class kiln burnt/ picked jhama bricks as per direction of the Engineer-in-Charge. This shall be laid to the specified thickness and in proper bond. No extra half bricks or brick bats shall be used than are necessary to complete the bond. Each course of bricks, shall be laid such that the top surfaces is perfectly leveled and in  smooth  gradient.  All  longitudinal joints shall be horizontal and perfectly in straight line.

Brick Block Pitching:-

Brick block shall be made of first class kiln burnt brick work in cement mortar to the required size and thoroughly cured as per direction of Engineer-in-charge. The laying shall be done in the manner as for brick pitching. Finishing the top surface with cement sand mortar in specified proportion will be followed by curing and subsequent leveling. While finishing this top surface, care shall be taken to see thatthe gaps in between blocks are not filled up by mortar.

Cement concrete block pitching:-

Cement concrete blocks for (a) protection to the bank slope of irrigation canal / drainage channel to minimize seepage loss, ensure stability  of slope and  improve conveyance capacity,  and (b) protection to the riverside slope of embankment to ensure stability and to prevent scouring or damage against wave action or high flow velocity, shall be designed as per codal provision and/or sound engineering practices, keeping in view the objective of end use and durability. Such block / lining should always be placed over a properly designed conventional or geotextile filters, to avoid possibility of failure against pore water pressure.

2.3.3.1 Precast cement concrete blocks, made in casting yards with finished top surface with cement sand mortar, followed by curing are to be laid in position over the  filter  bed,  and levelled, with a nominal gap of 6mm between the adjacent units. Such gaps may be created by removable plyboard shuttering or unremovable thermocol boards. There is no need of filling up  the gaps.

2.3.3.2 Cast-in-situ cement concrete blocks / linings shall be laid, by casting in alternative panels,  or otherwise, with shuttering on four sides and with a  layer of thick polythene sheet at  bottom   (of thickness 100 mm), to prevent clogging of filter due to intrusion of cement slurry,  during casting. Side shuttering may be removed within 3 to 5 hours after casting. Gap between the adjacent blocks should be at least 12mm, to be  kept preferably using removable side shutterings  or thermocol boards. In case removable shutterings are used, the gaps are to be filled up and compacted by 5.6mm down coarse aggregate. Finishing the top  surface  with  cement  sand mortar, will be followed by curing. While finishing the top surface, care is to be taken to ensure  that the gaps in between blocks are not filled up by mortar. In case of  plan  dimension  of  individual units of block / lining exceeding 1 sqm, or in case of excessive seepage observed particularly at the lower portion of the slope, causing sloughing or scouring of  soil materials, 50mm dia PVC pipes, with 300mm embedment into the virgin ground and top flush with the finished surface of the block / lining may be inserted at the centre of each block / lining and the pipes may be filled up and packed by 20mm down well graded coarse aggregates, to create additional pore water pressure dissipating device, in addition to the gaps lying along four sides of such units. Rate of supply, fitting and fixing of such PVC pipes may be analyzed by the construction wing, using PWD (Sanitary & Plumbing) and PW (Roads) SoR.”

Boulder Pitching:-

This shall be done with Pakur, Panchami & North Bengal variety of stone boulders to cover the  area to be pitched with boulders of size not less than 0.015 cum approximately and weighing  about 25kg and above. The boulders shall be arranged in layers and packed close together to the required specified thickness and made up to the proper slope. Smaller broken stones are to be  used in filling the space between the bigger ones. Each working Divisionshall use the stone boulders from the nearest available quarry site.

Stacking and dumping of boulders pertaining to Anti Erosion Works:-

Attempt shall be made to stack the boulders at a safe zone as close to the worksite aspossible keeping in view the extent of erosion and likely submersion ofthe stockyard by flood spill. In case the boulders are required to be stackedbeyond the initial distance from the anchor point of the spur forwant of space, prior written permission from the Engineer-in-charge is tobe obtained by the agency to that effect.

While stacking, boulders are to be packed keeping void asminimum as possible, only l/7th of gross volume is deducted as void and net volume is arrived at. The stacking shall be done layer  by layer without any vertical gap in between two consecutive layers. All stacks as soon  as measured shall be numbered serially with location in reference to permanent objects.

During taking measurement of stacked boulder by responsible officer, the measured stacks shall serially be numbered with oil paint and be marked with spreading liquid lime by the concerned agency for which no extra payment will be made. The serial number of stacks shall also be maintained in the measurement book also for the facility of the check measurement.

While checking measurement of stacks of boulders by officers other than those who recorded initial measurement some percentage of the stacks chosen at random shall be restacked in presence of the officers checking the measurement so as to verify whether the stacks have been made in proper manner or not. This percentage shall normally be not less than 2% in case of S.D.O.'s and 1% in case of Executive Engineer's checking. No extra payment  for such restacking  will be admissible.

The alignment of the spur shall be properly marked over the entire length of the spur by bamboo or sal bullah piles for which separate payments will be admissible as  per  provision of item in the schedule of work.

The measurement of stacks of boulders shall be verified with those recorded in measurement book before dumping is started. After the close of each day's work the balance portion of the broken stacks, if  any, shall be  measured and  approximate quantity recorded by  the supervising staff before leaving the site. At the time of resuming the work next day, previous day's measurements for the said stacks shall be verified before allowing dumping.

Dumping by boat shall be done for constructing the portion of the bar which will be under water. For constructing the anchored portion as well as the portion above the water level of the river, provision of boats will not be necessary and this shall be done by dumping boulders by head load only.

Dumping of boulders shall always be made in presence of a responsible officer not below the rank of Junior Engineer. The quantity dumped day to day shall be separately recorded by supervising staff with reference to serial number of stacks in addition to recording  in measurement book by the junior Engineer concerned.

Boulders shall be simultaneously dumped over the entire length of the bar below water so  that the bar is raised vertically at a uniform rate. Requisite number of  boats shall be  mobilized  at  each site and the loaded boats shall be aligned properly along the side of the spurs before each dumping. After the placement of all the boats have been made and duly checked, the dumping shall be simultaneously commenced. The cycle shall be repeated for each trip of the boat.

For each boat lead, challans shall be prepared in triplicate; one shall be retained  by  the supervising staff at the loading site, the second copy shall be handed over to the agent of the contractor and the third copy to the boatman to be  again collected back by  the supervising staff  at the dumping site as soon as the unloading is completed. The agency at the time of submitting the bill, shall enclose the second copy of challan. Each challan shall indicate the approximate quantity of boulders carried by the boat.

For easy identification the boats shall be prominently numbered by the contractor at his own cost for which he shall have no extra claim to the department on this account.

Sausages Works:-

Sausage works may be  of  different shapes like rectangular, square or circular type of various   sizes depending on the site condition. The fill materials inside the sausage crate may be either by picked jhama /1st class kiln burnt bricks or with stone boulders. For  launching sausages from bank, rate is inclusive of making ramps and supply of all equipments including carriage within a lead of 60 metre and all lifts complete.

Sausage cage made with Picked Jhama /1st class kiln burnt bricks:

Full bricks 1st class kiln burnt or picked jhama (413 nos per cubic metre volume of sausage) are rolled inside the sausage cage made with 10 SWG G.I. wire of internal dimension of square mesh 100 mm × 100 mm, with a minimum lapping of 150 mm wire  net  as  per  direction of  the  Engineer –  in  –charge. The top &  bottom face of the  sausage  shall be  tied by  double ply 12 SWG

G.I. wire at an interval of 0.60 m longitudinally & laterally. The ends of sausage shall be properly closed with end pieces by sewing with 12 SWG G.I. wire including inter twisting the free ends of  the wire at the junction as per direction. The cost is inclusive of al l materials, carriage upto site, labours for making, filling sausage cage & preparation of bed in standing or flowing water upto

0.30 metre depth complete. The cost of end pieces of wire netting will be paid extra as separate item.

Sausage cage made with boulders or lump aggregates etc.:

The boulders shall be filled inside the sausage in well packed & perfectly dressed condition. Sausage shall be made with 8  SWG /10  SWG  G.I. wire of square mesh size 125 mm ×  125 mm  wire netting or square mesh size 150mm x150mm wire netting as per requirements with a minimum lapping of 150 mm as directed by  the  Engineer  –in-charge. The ends of the sausage  shall be properly closed with end pieces sewing with 10 SWG/12 SWG G.I. wire as per direction including inter twisting the free ends, tying the face of the sausage by double ply wire at  an  interval of 0.60 metre longitudinally and laterally. The sub-grade shall be prepared before laying the sausage and the laying shall be  done in  stagnant or flowing water upto  0.30  metre depth. The wire netting shall be  held straight before placing the boulders. The rate is  inclusive the cost   of required wire netting, binding wires etc. carriage upto site and all the labour charges required for making, sewing etc. the sausage cage including filling with boulders   or lump aggregates in   the same as per direction of Engineer-in -charge.The lump  aggregates  constitute  any  type  of solid aggregates like singles,sprawls, cobbles, brick bats,brick ballasts,  stone  metal,sand  etc.  filled in bags suitably placed inside the sausage crates as per direction of the Engineer-in-charge. The cost of boulders or lump aggregates including it’s carriage upto site will be  paid separately. The cost of end pieces of wire netting will also be paid extra as separate item.

Driving Mild Steel Sheet Piles:-

The driving of M.S. sheet piles will be done in the river bank or in the bed of river even in tidal condition or on the ground or in trenches in all kinds of soil,  sand,  soil  mixed  with  gravel, shingles and pebbles etc.

Clutches of sheet piles shall be  cleaned and examined for metal wire edge lugs (scales)  and deflections that interfere with driving of sheet pile. Besides, the above clutches shall be examined for rectilinearness and safety. Clutches shall be checked  by  pulling templates through it. The template is piece of steel pile of the corresponding section, more than 5.50metre of specified length. Clutch longitudinal deflection (along) the line of pile shall  not  be  more than 1mm per liner metre of sheet pile. All defects of sheet piles  is  to  be  eliminated before driving. If in the same sheet piles there are such defects which cannot be eliminated those sheet piles shall be rejected/removed from site.

During driving of sheet piles, it is necessary to carry out strictly  in  accordance  with designs and specifications. Areas where sheet piles are to be driven shall be prepared as per general directions of the Engineer-in-charge. Piles shall be driven properly interlocked and piles which go out of clutch shall not be permitted. Sheet piles may be required to  be  driven  in  trenches back filled with local sand if cobbles or similar layers do not permit to drive the piles  below. Sheet piles shall be painted with one coat of approved Tar primer or equivalent and two coats of anticorrosive ready mixed oil bound paint. To keep verticality of  sheet piles as well  as  the designed alignment of sheet piles and required contours,special guides shall be provided during pile line and on the plane perpendicular to it. The position of every sheet pile in plan shall be checked with reference to the guides and vertically along sheet pileline by plumb.

After plumb checking, measurements when driving next sheet pile shall be taken in every   6 sheet piles. Sheet piles getting out of plumb in plan shall not exceed 150mm  at  pile  top level and 100mm at ground level.

Taper piles or junction piles as required shall be manufactured. Where the inclination of  the pile in the direction of driving exceeds permissible limits, it shall be  set  right  by  the contractor for which no extra payment shall be made. The special and tapered sheet pile shall be manufactured with rivets and laps. If it is permitted to manufacture  the  above  sheet  piles welded, perfect quality of welding and safety of welding shall be ensured during driving.

While driving sheet piles with vibrosinker, it is necessary to follow directions given in the operational instructions of vibrosinker. Fastening of vibrosinker to sheet pile  shall  be  rigid.  During driving, the bolt connection shall be periodically checked and bolts tightened. Axis of vibro-sinker shall coincide with sheet pile axis. Tolerances in sheet pile opening meant for jaw wedge of vibro-sinker shall not exceed 2 mm for distance between pile end and upper wedge of opening and 4 mm for other dimensions. Alternatively, pneumatically operated jaw grips can be used.

If during driving, piles deviate from vertical position, it shall be lifted up, corrected and  then driven again. If it is found that clutch or weld seam has been broken  or  some  other breakage has occurred affecting the work of sheet pile line, that sheet pile shall be extracted immediately and replaced by a good one at contractor’s cost.

For smooth lifting and lowering of sheet piles, the machine used for work shall be  equipped with corresponding crane equipment and attachments. Velocity of lifting crane hook when extracting sheet pile with vibration shall not be more than 3  metre/minute for sandy soil  any 1 metre/minute in case of clayey soil.

When keeping and handling sheet pile, safety measures shall be observed to prevent it from damage i.e. overstrain of materials, clutch damage etc. All deviations from technical specifications which may take place in the process of carrying out of sheet pile driving work, as  new points not dealt with in the technical specifications shall be done as per instruction of the Engineer-in-charge.

In the process of driving sheet piles, register shall be kept in which every driven pile shall be recorded with its length, time and driving, equipment used. All conditions of driving shall also be recorded and maintained.

Payment to the agency for driving sheet piles shall be made at the unit price per square metre of sheet piles actually driven including the cost of allhandling, cleaning, painting, driving, cutting and riveting/welding where required fabricating taper piles and making holes in the piles where required, fabricating corner and special junction piles, replacing defect piling etc. in accordance with the provision made in the foregoing paragraphs complete.

No concreting of the toe wall trench covering the projected length of the top of the sheet pile shall be allowed until the same are checked by the competent Engineer and his approval for commencement of concreting is received.

Installing geo textiles:

Site Preparation:-

Clear and grade the installation area. Before installation of the geotextile, the site  must  be cleared of large and sharp stones, tree stumps or any other objects that could damage the geotextile. Cut trees and shrubs  flush with the sub  grade.  Removal of  topsoil and  vegetation mat is not  necessary, but is  recommended where practical.  Excessively soft  spots or voids may be  unsuitable for geotextile installation. Fill these areas with select material and compact prior   to geotextile installation. The problem area may be enhanced by using a geotextile at bottom of  the excavation prior to backfilling. If heavy construction equipment is used, driving on the geotextile must be avoided.

Deployment of the Geotextile:-

Unroll the geotextile on the prepared sub grade in  the direction of construction traffic.    Hold     the  geotextile in place with pins, staples, fill material or rocks.   Adjacent rolls  shall overlap in    the direction of the construction. Depending on the  strength of  the  sub  grade,  the  overlaps may have to be sewn.

Placement of the Aggregate:-

Place the aggregate over firm subgrades by back dumping aggregate  onto  the  geotextile  and then spreading it with a grader. For weaker subgrades, dump onto previously placed aggregate  and then spread the aggregate onto the geotextile. On weaker subgrades, a sufficient layer of aggregate must be maintained beneath all equipment while dumping and spreading to minimize the potential of  localized  subgrade  failure. Avoid  traffic  directly  on  the  geotextile.  When  using construction equipment on the aggregate, try to avoid any sudden stops, starts or sharp turns. Maintain a minimum lift thickness of 15 cm except in cases of low volume roads. Compact the aggregate to the specified density using a drum roller. Fill any ruts with additional aggregate and compact as specified.

In addition to the application and function to be covered by the geotextile, it is important  to consider the following:

Before installation, check if the packing foil is  complete. If  not, check the geotextile roll  for damage due to UV radiation or mechanical impacts.

Before installation of the geotextile, the site must be cleared of large and sharp stones, tree stumps or any other objects that could damage the geotextile.

Secure the geotextile from wind forces, for example by placing small bags with sand on   the fabric to hold it in place.

If heavy construction equipment is used, driving on the geotextile must be avoided.If several rolls of geotextile are used for the installation, joint overlaps shall be made correctly either by sewing or by using adequate overlaps, depending on the application and soil conditions Prior to covering, the geotextiles must be inspected to ensure that the geotextile has not been damaged during installation.

Joints and overlaps:-

In installations where more than one roll of geotextile is used, the joint overlaps shall be made either by sewing or by using adequate overlaps.

The requirements to the joints depend on the application and soil conditions in question

The larger the deformations which can be expected, the greater the requirements for the overlap.The table given below can be used as a guideline. The requirements are specified for typical road applications. For larger hydraulic structures, the minimum overlap shall never be below 500 mm and is often required to be minimum 1 metre. Overlap requirements/ASSHTO M288

Soil CBR

Minimum overlap

Greater than 3

300 - 450 mm

1 - 3

0.6 - 1 m

0.5 - 1

1 m or sewn

Less than 0.5

Sewn

Sewing is a good alternative to overlapping, especially when the  required overlaps are quite large, for example close to  and above 1  m.   Sewing can be  carried out  using different   types of threads and seams. It is therefore important that the quality  of  the  seam.  This is typically done by testing the seam according to EN ISO 10321 “Geosynthetics - Tensile test for joints/seams by wide-width strip method”.

Geo Bags:-

The geo-textile bags of different size will be manufactured using the Polypropylene UV stabilized needle punched non woven Geo-textile having requisite properties. The two long end will be double chain stitched with polypropylene or equivalent yarn. The material will be  supplied at site as desired by the Engineer-in charge with the required test report as asked by the Engineer-in-charge.

Composite Geo Bags:-

The composite geo-textile bags of different size will be manufactured from Polypropylene UV Stabilized Woven Geo-synthetic material and Polypropylene UV stabilized needle punched  P  P  non woven Geo-textile material having requisite properties. The  woven geo-textile will be used  as outer layer and the non-woven geo-textile will be used as inner liner. Initially the two types of sheet of required dimension has been laid one above another and stitched together. Then this composite material will form a bag by stitching the two long end by double chain stitch with polypropylene or equivalent yarn. The material will be supplied at site or as desired by the Engineer-in-charge with the required test report as asked by the Engineer-in-charge

“2.7.7 – Specification of woven geotextile as filter materials and to be used in Geobags”

Sl No. Property Unit Test Method Desired Value
1 Weight Gsm ASTM D 5261 430
2 Tensile Strength Warp/Weft KN/M IS : 1969 70/70
3 Elongation at specified Tensile Strength. Warp/Weft % IS : 1969 27/25
4 Trapezoidal Tearing Strength Warp/Weft N ASTM D 4533 1500/1500
5 Puncture Strength N ASTM D 4833 1200
6 Water Flow Lit/m2/Sec ASTM D 4491 25
7 AOS mm ASTM D 4751 0.425
8 U.V. Resistance after 500 hrs %strengthretained ASTM D 4355 >= 80

 

“2.7.8 – Specification of non-woven geotextile as filter material  and  to  be used in Geobags”

Sl No. Property Unit Test Method Desired Value
1 Weight Gsm ASTM D 5261 300
2 Tensile Strength KN/m ASTM D 4595 17
3 Elongation % ASTM D 4595 > 60
4 Grab Tensile Strength N ASTM D 4632 1050
5 Grab Tensile Elongation % ASTM D 4632 > 60
6 Trapezoidal Tearing Strength N ASTM D 4533 425
7 CBR Puncture Strength N ASTM D 6241 3100
8 Thickness mm ASTM D 5199 2
9 Flow water rate - 5 cm head Lit/m2/Sec ASTM D 4491 55
10 AOS mm ASTM D 4751 0.015
11 U.V. Resistance after 150 hrs %strengthretained ASTM D 4355 >= 75

Sampling and Testing

Geotextiles must be tested by the  Client / Engineer-in-charge at    accredited  or well equipped laboratories (e.g. BITRA, CIPET, Jadavpur University, etc.) having all testing facilities prescribed above. Cost of such testing, deemed to be 3rd Party Testing would have to be borne by the Engineer-in-charge and the responsibility of taking samples, and sending to laboratories shall entirely be vested on him, for which necessary provision for cost shall be made in the estimate, but may not be included in the BoQ of contract. This apart, the contractor also shall furnish Manufacturer’s  Test  Certificates  (MTC) from either own laboratory of from accredited laboratories stated above. No payment shall be released without MTC and full payment shall not  be  released until results of 3rd Party Testing are made available. In case of non compliance of the results of 3rd Party Testing with the specified parameters, the Engineer-in-charge shall make payment at reduced rate on  pro-rata  basis  as  stated below.

Criteria Reduced rate of payment
Sl.1     to @ 10% (for each
Sl.7 criterion)
Sl.8 @ 50%

The sampling and testing frequency must be in accordance with the following:

Batch or order size (sqm) defined as the lot size

No.of samples representing the lot

Initial 10,000 sqm or part thereof (Plan area of

each geobag may be taken as 0.7 sqm)

1

Each subsequent 10,000 sqm or part thereof

1

Identification and Storage

The geotextile rolls / geobags must be clearly labeled showing, manufacturer, month and year of manufacture, batch identification mark and any other information as required by the law in force.

Geotextiles must be stored under protective cover or wrapped with a waterproof, opaque UV protective sheeting to avoid any UV damage prior to installation.

Geotextiles must not be stored directly on the ground or in any manner in which they may be affected by  heat. The method of storage must be  in  accordance with the recommendations set by the manufacturer.”

Specification of High Density Polyethylene (HDPE) Woven Bags

Sl No. Property Unit Test Method Expected value
1 Length cm IS 14252 84 + 2
2 Width cm IS 14252 38 - 1
3 Ends per dm and Picks per dm   IS 14252 40+1
4 Mass of sack (without tying cord) gm IS 1964 55+2
5 Average Breaking Strength of fabric, Min (Ravelled strip method,325mm x 70mm), Warpway / Weftway N(kgf) IS 1969 750(76)+6
6 Average breaking strength of bottom seam, Min (Ravelled Strip method) Elongation at break of fabric (Ravelled N(kgf) IS 9030 314(32)
8  Strip method), bothwaysAverage breaking strength at break of UV stabilized HDPE fabric after been exposed to UV radiation and weathering (after 192 hours),Min % IS 14252 50
19 Ash content, Max % IS 14252 2.2
Note :- The mass of the sack is based on fabrics weighing 75 gsm; 1N=0.102kgf (approx.) 

Sampling and Testing

Printing Packaging and Marking

Printing, packaging and marking shall be in accordance with the provision of Clause 5 of IS: 14252:2015. Each bag shall carry the following:

Manufacturer’s name and logo

BIS Standard Mark

Manufacturer’s BIS License Number

Month of manufacture.”

Sampling and  testing of the HDPE woven bags shall be in  accordance with relevant provision  of IS: 14252:2015 or other Codes mentioned in that Code. Procedures described for making payment in relation to sampling and testing shall be similar to the provisions of Para 3.7.9.1 stated hereinbefore.

No bag shall be accepted without the above information

Properties of the material of the Polypropylene Rope Gabion:

  Properties Limits
1 Weights 40 gm/ metre or more
2 Tensile strength a) 9mm dia rope, Breaking strength>= 1560 Kg
b) Punching shear:- 6000 Kg to be tested as per IS: 7071
3 Construction of Net Interlaced at the intersection of ropes Residual breaking strength of at least 85% of the
4 Abrasion Resistance stipulated rope strength at the end of 1000 cycles, when tested as per IS: 7071
5 Thermal Stability The rope tested as per IS: 7071 shall have a residual strength of 90%
6 U V Resistance More than 80% strength retention after 500 hours of outdoor weathering as per ASTM D 4355

Testing and compliance procedures, conforming to relevant IS / ASTM Code,  with  the  frequency of sample as may be agreed upon between the Engineer-in-charge and the Contractor or as may be prescribed in the relevant codal provision. Linkage between 3rd party testing and payment, in a manner similar to the provision of Para 2.7.9.1, may be established, before invitation of tender.”

Specification of Tetrapod:-

Casting of Tetrapod:-

Tetrapod units shall be measured in numbers for casting and rates shall cover all cost that are necessary for casting, curing to complete all items according to specification and will be  paid  under respective items of Unified Rates of schedule and SoR of PWD.

Grade of concrete of Tetrapod is M35 cement concrete.

The concrete shall be designed to the design mix as relevant IS Codes. Data for preliminary Mix Design for M35 (Tetrapod concrete)

Characteristic compressive strength of concrete at 28 days is 35 N/mm2

Degree for workability – As per relevant I.S. code

Maximum free water cement ratio- 0.45

Minimum cement content – 440 Kgs for M35

Type of exposure- Severe

Maximum nominal size of aggregate 20 mm

Standard deviation of compressive strength of concrete – 5 N/ mm2

Notwithstanding the foregoing, the standard deviation shall be  determined from the test results as soon as 30 samples are tested.Mix design shall be performed for severe exposure condition.

Proportions of Materials:-

Concrete mixes shall be proportioned to give workable, dense concrete, which can be thoroughly compacted within the shuttering. The mix proportions for fine and coarse aggregate shall be complied with the requirements for designed concrete mixesaccording to IS: 456 for concrete. The proportions of cement, fine and coarse aggregates and water proposed by the contractor for use in the works for grade of concrete shall be subject to approval by the Engineer-In-charge and results from the preliminary tests from trial mixes, shall be satisfactory to the Engineer-In-charge as outlined in the relevant IS Codes. (Trial Mixes and Preliminary Tests) The contractor shall arrange to carry out necessary calculations, all the tests for determining the grade of concrete at his own cost and the approval of Engineer-In-charge is mandatory. The proportioned weight of coarse aggregate and fine aggregate to produce the concrete of required strengths.

The proportion of cement, aggregate (Fine and coarse) and water to determined.

The sieve analysis of aggregates which they proposed to use in the works.

Full details of preliminary tests on concrete and

All the calculations relevant to the design of grade of concrete mix

Armour Layer (Tetrapod):-

Armour layers shall be placed to the levels as directed by the Engineer-in-charge, based upon the levels and the thickness shown in the drawing. The Tetrapod in  the  armour layers shall be placed individually in two or more layers such a manner as toensure close interlocking of Tetrapod and reduce the voids in the armour layers as for as possible.

Casting of Tetrapods (ArmourLayer):-

The contractor shall make his own arrangements for making form work, moulds etc. for casting Tetrapod. The Casting yard shall be provided near the site by the Engineer-In-charge and the contactor shall lift the tetra pod after casting,curing and stack them in the stacking yard. Any damage to tetrapod for any reason, the cost of the same will be recovered from the contractors running bill, which may become due to the contractor.

The contractor shall submit drawings and substantiate their proposals, showing details of the shuttering he intends to use for the approval of the Nodal officer. Shuttering shall be made from steel plates and shall be of suitable design and substantiate construction to carry the loads due to the wet concrete and any incidental loads without inadmissible bulging, distortion or deflection.

Any changes or modifications to the shuttering required by the Engineer-In-charge shall not entitle the contractor to any extra payment. Shuttering shall be sufficiently tight to prevent loss of water or mortar from the concrete. Special attention shall be paid to shuttering where pokers or shutter vibrators are to be used. All shuttering shall be accurately  aligned and have  close fitting joints. The outside of steel shuttering must be painted in light color to reduce temperature gain due to solar radiation. All shuttering surfaces in contact with concrete shall be treated with an approved composition before usage to prevent  adhesion of  the  concrete. The  use of diesel, mineral or engine will adhere to or discolors the concrete, shall not be used.

All tetrapod shall be on horizontal and rigid beds. Each tetrapod shall be cast in one continuous operation and no construction joints in the concrete will be permitted. If  the  contractor shall, for any reason whatever, only partially complete the casting of  any tetrapod, such unfinished Tetrapod shall be rejected at contactor’s cost and risk.

All concrete surfaces shall be smooth, any fins occurring at formwork joints shall be removed and honey comb filled with mortar after getting approval from  the  Engineer-In-charge for doing so.

All concrete is to be protected during hardening from the direct rays  of  the  sun  and drying winds. A record of dates of concreting the tetrapods shall be  kept by  the contractor and  the dates and numbers shall be prominently displayed on the tetrapods.

Transporting and Placing of Tetrapod:
Tetrapod units shall be measured in  numbers for  transporting and Placing in  position.  The rates for transporting and placing Tetrapod shall cover all costs that are necessary for lifting, transportation, placing and fixing in position to complete all items according to specification and will be paid under respective items of Unified Rates of Schedule.

The contractor shall engage cranes of suitable capacity and boom  length  for  easy  handling and placing at the required reach. The contractor shall engage skilled labours for the work.

Reinforced Cement Concrete Porcupine:-

The R.C.C. Porcupine basically consists of 9 (nine) R.C.C. members of dimension 150cm x 10cm x 10cm. Such 3 (three) members are casted monolithically by cement concrete (1:1.5:3) and  requisite reinforcement in triangular shape in such a manner that the inner  side  form  a equilateral triangle of dimension 60 cm and the rest part projected. A hole of diameter more than 25 mm will be made at mid length of each member. Such two nos of monolithically casted members will be joined with three nos. of individual member with 25mm dia nut &  bolts along with washers. For smooth finished surface the shuttering will be finished with polythene  sheet. The reinforcement will be 4 nos. 6mm dia HYSD bars as main  reinforcement  and  6mm  dia  stirrups @ 200 mm c/c. After casting, curing and fitting, fixing complete, the Porcupines will be placed at the bank or bed of the river / sea or dumped from the boat under water as  directed by the Engineer-in-charge.

Special items for Sluices: General:

Shutters, fixtures, hoisting arrangements etc. shall be designed and proportioned in  such  a  way so that the sections are commensurate to the water pressure and permit smooth drainage, whenever required, at a minimum head difference.

All materials / bought out components for embedded parts, gates, hoists and allied works shall conform to relevant Indian standards / technical specifications and approved drawings.

The basic rates are inclusive of cost of all materials, machinery, labour, fabrication, erection, commissioning and testing of gates, hoists and other related components as per  technical specifications.

Detail Components:- Shutter Leaf:

Minimum thickness of the skin plate and angle stiffeners shall not be less than greater of the following unless specifically mentioned otherwise by the Design Wing. Designed thickness plus 1.5 mm as corrosion allowance.

8mm for shutters of R.C.C. spun pipe inlets and other box inlets/sluices upto discharge of

5.5 cubic metre /sec. and 10 mm for all other sluices. Continuous fillet welding, not  less  than 6 mm size, shall be done all along the members as per IS: 9595 with electrodes as per IS: 824. Mild steel shall conform to IS: 226/2062 depending on requirement  of  weld  ability  and Manufacturer's test certificates are to be furnished, if required by the Engineer-in-charge.

Hoisting Fixtures:- Draw shutter

The screw gear rod shall be of mild steel conforming to IS : 226. Cast iron guide channels conforming to IS: 210, adequately proportioned to  allow  for  upward and  downward movement of the shutter with sufficient clearance and inside machined and shall be true to plumb and fixed with the R.C.C. / masonry with necessary hold fasts. The cost of necessary R.C.C.  /  masonry work is included in the item. The guide channel shall permit proper abutting of the rubber seal. The wheel and the pedestal shall be of cast iron, and the pedestal shall be compatible with the wheel and the gear rod. Minimum thickness of cast iron members shall not be less than 20 mm. The pedestal shall be properly anchored with concrete sill beams by anchor studs / bolts of diameter not less than 20 mm.

Flap Shutter:-

Suitable double hinge fixture shall be  manufactured from  forged steel of  thickness not less than 16 mm conforming to IS: 2004 and the junction of the bent  portion  shall  be  continuously welded. Long tie rods shall be mild steel of not less than 28 mm diameter. Angle  members partly engraved in concrete/masonry for supporting the tie rod shall preferably be cast steel of Grade 23-45 (W) of IS: 1030 for better corrosion resistance than mild steel. Thickness of such members shall not be less than 25 mm.

Sealing Arrangement:

Suitably designed 'Flat type' or 'Musical note type' rubber seal made up of molded/extruded natural or synthetic rubber conforming to IS: 4622 shall be used. The rubber seal along with MS/CI flats is to be fitted with shutter leaf with suitably spaced nuts and  bolts, cost of which is included in the item.

The rubber seal, particularly in case of flap shutter, shall abut against smooth  and  perfectly aligned steel surface to ensure water tightness. For this purpose, a suitably designed M.S./Cast steel liner frame may be manufactured and fixed with concrete/masonry surface, by suitable anchor bolts/studs.

Bituminous Paint:

Bituminous 'paint of approved make and brand shall be used as per Manufacturer's specification. Bituminous paint is specially suitable in painting of shutters and other accessories like pedestal/ capstan Block, C.I. wheel etc. where aesthetics is not much of importance  particularly for inlet structures and small sized drainage sluices. No extra primer is required to be provided for bituminous paints. The rate of removing old paint and preparing the surface is included in the item.

ABBREVIATION USED IN USoR
Abbreviated Form   Expanded Form
ASTM : American Society for Testing and Material
av. : Average
Cft, ft3 : Cubic foot (feet)
CI : Cast Iron
Cm : Centi meter
Cum, m3 : Cubic meter
DBL : Designed Bed Level
Deptt. : Department
dia, Dia. : Diameter
1st : First
ft : Foot, feet
G.L. : Ground Level
GI : Galvanised Iron
GM : Gun Metal
gm : Gram
GSM : Gram per Square Metre
H.P.-Hr : Horse power-Hour
I&WD : Irrigation & Waterways Department.
I&W Dte : Irrigation & Waterways Directorate.
in3 : Cubic inch
IRC : Indian Road Congress
IS : Indian Standard
Kg : Kilogram (s)
Km, K.M. : Kilometer (s)
KN/M : Kilo Newton per Metre
lb : Pound
Lit : Litre
M., m. : Metre (s)
mm, MM : Mili meter
MS : Mild Steel
M.T., M.Ton : Metric Ton
No., no., nos. : Number (s)
N : Newton
PW : Public Works
PWD : Public Works Department
RCC : Reinforced Cement Concrete
R.C. : Reinforced Concrete
Rly. : Railway
Sec. : Second
Sq cm, cm2 : Square centimetre
Sq m, m2 : Square meter
SWG : Standard wire gauge

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