Percentage rate contract This is modified form of

Ø Percentage rate contract: This is modified form of item rate contract. it consists of bill of quantites consists of the description of items as per sanctioned estimate with their quantites, rate, unit & amount. The contractor is asked to quote only Above Below At Par with the rates shown in the estimates. The same % is applicable for all the items of the work. There is no possibility of unbalanced tender. The work of scrutiny of tender is very simple. Visit for more Learning Resources

Ø Advantages: • 1. There are no rates for individual items the benefit due to increase in quantities will not be availed by the contractor. • 2. Comparative statement can be prepared quickly. • 3. Overwriting & erasing of rates etc. can be avoided.

Disadvantages: 1. contractor may quote rate too low or too high in such case it is too time consuming to cancel the lowest tender , to get approval of higher authorities. as there is no guarantee of quality. 2. tenders can form the ring. This lead to loss of govt money. 3. Two or more contractors may quote the same rate with negotiation then it is difficult to allot the work to any one contractor. 4. The total cost of work is not known until its completion. Suitability: 1. All major works of public bodies like dam, roads, buildings

Labour contract: Rates are quoted only for the labour for all items of the work. The material is supplied by the department free of cost. The arrangement for the tools and plants are made by the contractor. The owner has to keep close watch on consumption of materials as the contractor is least bothered about that. The contractor is not affected by fluctuation of rates. The chances of disputes are less. The quality of work is assured. Suitablity: 1. For PVT. sector. the owner can get the material at the cheap rate.

Advantages: 1. The materials stored by the dept. are utilized. 2. Quality of work is maintained. 3. Increase in cost is checked in spite of any rise in prices of materials. Disadvantages: 1. Delay in obtaining materials. The contractor himself required to be in touch with the dept. 2. Theft, shortage of materials , accounting of materials are constant worries for the dept.

Lump sum contract: the contractor aggres to complete the work in fixed time for a fixed money. The detailed specification, drawings, SD, Penalty, progress of work and the other conditions are included in the contract agreement. The quantites of item is not provided. For any extra work the contractor is paid Advantages: 1. The owner knows before hand the exact cost 2. For payment the detailed measurements are not required. 3. Excellent planning & effective management is possible as there are no addition & alterations.

Disadvantages: 1. No extra work is allowed. 2. The quantites of works are not guaranteed therefore there is risk to the contractor. 3. The contractor may submit high tender. Sutability: 1. Road work 2. building works 3. plumbing works. Not suitable for -----Repair works, works of addition & alteration. ----- where foundation conditions are not ascertained.

Target contract: It is a combination of cost plus % & cost +fluctuating fee contracts. The contractor is paid on cost + % basis for the work executed and in addition he receives plus or minus on savings or excess effected against the agreed estimated cost or target cost. The target amount is worked out by measuring the work after completion & valuing at pervious agreed rate.

Advantages: -it is an encouragement to the contractor to use his skill & experience. --Both parties will be benefited. --Negligence is minimized. Disadvantages: --the contractor may show higher cost of construction to gain more profit.

Negotiated contract: If the contract is given by negotiation, it is known as negotiated contract. There is no open competition & the owner negotiates with selected contractors after studing their pervious experience & reputation. In this method there are less chances of disputes. the competition is restricted, the work of selection is simplified. These contracts are not suitable for PWD. IN SPECIAL SITUATIONS WHERE THE TIME IS IMPORTANT FACTOR IT MAY BE USED. /EMERGENCY SITUATION/TO GET REASONABLE RATES.

ADVANTAGES: ----- economy in expenditure. ------ less chances of disputes. Disadvantages: ---limited persons. No open competition. ----not suitable for PWD.

Cost plus % rate contract: -owner agrees to pay to the contractor the actual cost of work plus an agreed % of cost as its profit. --drawings, bill of quantites, specifications are not necessary at the time of agreement. These may be supplied from time to time. the payment is made periodical on the basis of materials & labour on certification of engineer in-charge. or as per modes of payment agreed by both paarties. --No % is paid for overheads of contractor. --TA bills ---salaries of the staff.

Advantages: -The contractor is assured of his profit , whatever may be the fluctuations in prices of materials. --disputes due extra items is eliminated. --suitable for private work only. Disadvantages: -total cost is not known. --fictitious bills may be prepared. --Not suitable for govt. Suitable for emergency works & works involving difficult foundation conditions.

Cost plus fixed fee contract: -owner pays the actual cost of the work plus certain fixed amount/lumpsum amount as fees to cover his overhead charges & profit. documents are supplied at the time of actual work. -- payment to the contractor is made periodically based on material, labour, plants & equipments used. Advantages: -work gets completed speedily. ---dispute due to extra item is eliminated. --Quality of work is maintained. Disadvantages: --there is no incentive to the contractor. --Final cost is not known till the completion. -keeping of accounts staff is required.

Cost plus variable fee contract: -cost of work is paid to the contractor. --The fee to be paid is based on some sliding scale. --fee varies inversely to the increase or decrease of the estimated cost agreed by both parties. ---Higher the actual cost lower will be the fees. & vice versa. Advantages: --profit of contractor is linked with actual cost so economic completion of work. --Early completion. Disadvantage : profit is not assured & depends on economy achieved in construction.

Escalation: • This is the latest clause that has been introduced in the terms & conditions of the contract. espessialy after 1978 it has been experienced that the rates of construction materials are rising up as the purchasing power of rupees is following down. • The labour rates have gone up disproportionately like wise the fuel rates have been increased considerably. to meet these unforeseen circumstances escalation clause is inserted. so that the contractor shall get some relief.

As guided by ministry of labour. the labour rates are incresed. The public dept. have their own formulae. These are based on price indices declared by RBI with the help of statistical dept. of India. For labour rate commissioner of labour & directorate of employee. Formulae: V={(0. 88 R-C) X K 1/100 X (C-CO/CO)} V—Variation in price to be paid. R—Total value of the work completed. C=total cost of material supplied by the govt. =cost of sche “A” CO=consumer price index at time of filling the tender. C-Prevailing consumer price index K 1 -Labour component

V={(0. 88 R-C) X K 2/100 X (I-IO/IO)} V—Variation in price to be paid. R—Total value of the work completed. C=total cost of material supplied by the govt. =cost of sche “A” CO=Wholesale price index at time of filling the tender. C-Prevailing Wholesale component price index K 1 -Labour

Escalation: For large projects the time of completion of the project is large. The cost of material & labour goes on increasing day by day. It is difficult for the contractor to find such rise in labour & material cost while quoting the rate in the tender. This factor will affect the quality & progress of the work. to overcome such drawback price variation clause is included in the tender. As per the clause the contractor shall be paid for any such rise in price. the amount to be paid to the contractor shall be calculated by the empirical formula.

Ø Condition for application of the clause: -This clause is applicable for the work having estimated cost more than 5 lac. & duration more than -01 year. -The total aggregate cost shall not exceed 10% of cost of work. -It is not payable for extra items. -Price variation clause is operative for both. depending increase or otherwise.

Unbalanced tender: this is self explanatory term concern with the tender showing unusual rates or over rates for some of the items of work included in item rate tender. On the face such tender appears to be lowest but during the execution it proves to be highest paid bidder. Types: 1. Intentionally prepared by taking advantages of loose terms & conditions. 2. Due negligence of the estimator or oversight. This happens in case of ----lump sum contract --item rate contract in private works.

Example: CONTRACTOR SR. NO Particulars Qty A B C 1 SOFT SOIIL-I 500 M 3 300/ 120 300 2 SOFT SOIL-II 300 M 3 400/- 500 600 3 SOFT SOIL-III 200 M 3 400 -/- 1800 1000 4 C. C IN BED 100 M 3 4000/- 4000 3000 5 PLASTERING 800 M 3 400/10. 70 LAC 200 11. 30 LAC 300 8. 94 LAC

RING FORMATION: In case , when the no of tenders applying for various works are limited then parts of works can be decided to give to the different contractors by keeping view of expertise, financial capability. This is adopted to avoid collision among the contractors.

Chapter -05 Soil as a three phase diagram: Here Wa Air Va Wa=0 W=total weight W Ww Ws water Vw solids Vs Partially saturated soil V W=Wa+Ww+W W =Ws+Ww V=Total volume V = Va+Vw+Vs V = Vs +Vv Vv=va+Vw

Dry soil Wa Va=Vv Air ws solids Vs Vv= Volume of voids. Here Wa=0 Ww=0 absent Vv=Va V- Total volume V =Va +Vs W=Ws+Wa W =Ws

Saturated soil water solids Solids W= Total weight V=Total Volume Vv=volume of voids=va+vw Vs=Volume of solids W =Ws+Ww V = Va+Vw

Uses of three phase diagram: 1. it defines voids ratio , porosity, Degree of saturation& water content. 2. It is used to find volume of solids, water & air. 3. It makes the calculation work very easy. 4. It is used to determine weight of entire soil sample.

Water content: Ratio of weight of water to the weight o solids. denoted by “w” Expressed in % Water content= w = weight of water/weight of solids X 100 w = Ww /Ws X 100 w = W-Ws/Ws X 100 ( Ww=W-Ws) W= Total weight

W-of coarse grained soil is less than -fine grained soil, silt , clay. -the water content of fine grained soil is more than 50% also. ie-more 50% is the mass of water.

Void ratio: volume of voids to the volume of solids in given mass of soil. Denoted by “e” It is expressed in fraction. Vv=volume of voids=va+vw Vs= volume of solids Void ratio= volume of voids/volume of solids e =Vv/ Vs Porosity: Porosity=Volume of voids /total volume n =( Vs/ V ) x 100

Degree of saturation (s): = volume of water /volume ofvoids x 100 s=Vw/Vv x 100 Density “ῥ” : It mass of soil per unit volume it is expressed in kg/m 3 or gm/cm 3 denoted by (rho “₰”) ῥ =M/V Bulk density: total weight to the total volume ῥ =W/V

Dry density: The weight of solid per unit total volume of soil mass(before drying) =ws/V =Ww/V Saturated density Ὕ”(gamma) : It weight per unit volume of saturated soil. Or It is the bulk density when all voids are completely filled with water. Ὕ =W/V = Ws+Ww/Vs+Vw

Submerged density: It is the submerged weight of soil solids to the total volume. Here the weight of solids is completely reduced due to buoyancy. The voids are completely filled with water. Ysub=Ws (sub)/ (VS+Vv) Here V= VS+Vv Va=0 since Submerged Ws=Vw Ysub=Y sat-Yw Yw=unit weight of water =10 KN/m 3

Bulk unit weight : weight per unit volume of the soil. it is nothing but bulk density. ῥ =W/V Dry unit weight: It is the ratio of weight of solids to the total volume. Yd=Ws/V KN/m 3 G= Specific gravity=Weight of given volume of soil solids to the weight of distilled water of equal volume at 27 degree cen.

Density index: (ID) It expresses comparative denseness of soil w. r. t its loosest state & densest state. It is applicable for cohesion less soil( sand/silty soil) Loose state: Density index: (ID)= emax-e/emax-emin for loose state =e=emax ID=0 Dense state: e=emin ID=1 The actual value lies between 0 to 1 For more detail contact us