Estimation and costing of soil and water conservation measures……

Estimate

An estimate is calculation or computation of the quantities of materials needed for a particular work and expenses likely to be incurred in the execution of the work.

 

Necessity

  • To assess the financial requirements.
  • For obtaining the approval and sanction of component authority.
  • To access the economic feasibility of the project.

 

Types of estimates

  • Preliminary estimate or rough cost estimate.
  • Detailed estimate
  • Revised estimate
  • Supplementary estimate

 

Preliminary estimate

  • To decide the financial involvement for AS by the authority.
  • Cost of major components should be shown separately.
  • Brief report and site plan needed.
  • Prepared based on practical knowledge and similar works undertaken in the past.

 

Detailed Estimate

  • Based on the plan and sectional drawings.
  • Details of the works.
  • Quantities of different items of works.
  • Cost of each item.
  • Contingencies etc.

 

Revised Estimate

  • It also a detailed estimate.
  • Prepare when original sanctioned estimate is likely to exceed during the execution of work.
  • New components incorporated.

 

Supplementary Estimate

  • Detailed estimate of the additional work.
  • Is prepared when additional works are required to supplement the original work.

 

Preparation of estimates

  • Rates of items are worked out based on detailed data providing cost of materials, conveyance charges and labour as per schedule.

 

Data

  • The data book deals with the quantities of materials and labour required for different items of work.
  • Will remain unchanged by fluctuation in market rates.

 

SOR-Schedule of Rates

  • Prepared by the chief engineer PWD Administration.
  • Data from economics and statics department and current market rates are taken into account.
  • Is for estimating purpose.
  • Followed for original and maintenance works.
  • Consist of 2 volumes.

 

Conveyance Statement

  • Actual distances are used.
  • Taluk conveyance not used.
  • Certificate- “The distances noted in the data for conveyance from quarry or source have been personally verified by me and are found correct. These are the minimum leads require.
  • Rates available for lorry load, head load and boat load.
  • For hilly areas 15% increase in rates are allowed.

 

Lead

  • Lead or distance for removal-horizontal distance between the vertical central line of the pit cross section and the bank which is formed with the excavated material.
  • Measured in units of 50m.
  • Shortest practicable route.

 

Lift

  • Vertical distance.
  • ½ depth of the pit excavated +½ the height of bank formed with excavated earth + difference in level between the top of the pit and bottom of the bank.

 

Earthwork Excavation

  • Excavation in difference material to be estimated separately.
  • Ordinary soil- Any material yield to the application of mammati, spade or shovel.
  • Hard soil- Any material which requires the application of picks or scarifies to loosen.

 

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