Example

The construction of a major new factory on a greenfield site required a large earthmoving contract . The quantities of excavation and its subsequent disposal have ben included in the contract bills and priced by the contractor . i is found that the quantities of materials to be taken to tips has increased by 25 per cent by volume . This is due to variations to the contract and the unforeseen nature of some of the ground conditions of the construction site .

  The contractor's pre-tender report indicates that a variety of tips at different distances from the site will be used for the disposal of the excavated materials . The contractor's tendering notes indicated that the tips nearer the site would be filled first . In this case they result in lower haulage costs , but in this case are also shown to have lowwer tipping charges . The disposal of the excavated mateial therefore includes two separate elements :

- The haul charges to the tip
- The costs of the tip

In the contract bills , the rate used by the contractor for disposal of excavated materials represents an average rate . This is based upon calculated average haul distances and average rate for the disposal of the excavated materials can be calculated similarly for the actial quantities of excavated materials that are involved . The data is shown in Box 5.1

  To simply continue to aply the contract bill rates in similar situatins to that shown in Box 5.1 is erroneous .The rates no longer reflect the work to be carried out and the contractor's method of working , which have been changed by the variation to the contract . Other factors that might also need to be considered are the excavation of different types of construction materials that have been encountered , whether they bulk at different rates or whether they are more difficult to handle .

  The increase in the amount of excavated materials , on this scale , may also have other repercussions such as an extension of time which might also need to be considered . The method of carrying out the works might also now be different from considered . The method of carrying out the works might also now be different  from that originally envisaged by the contractor . Different types of mechanical excavations may be required or the plant originaly selected to do the work might no longer be the most appropriate . This is especially so where cut and fill excavations are considered . The contractor may also be involved in hiring additional plant at higher charges and employing workpeople at overtime rates , in order to keep the project on schedule .

  The contractor must , as a matter of good practice , always put in writing :

• Applications for instructions , drawings , etc .
• Application for the nomination of subcontactor
• Progess of the work and any delay
• Notification of any claims under the contract in respect of

1. variations
2. Extensions of time
3. Loss and expense .

• Confirmation of any oral instructions from the architect .

The contractor should also ensure that any certificates that are required under the terms of the contract are issued at the appropriate time . These may have some effect upon the vadility or otherwise of a contractor's claim at a later stage .