In one of the Road projects in Dubai, one additional works were instructed to the Contractor. This instruction was given as per the details shown on the Contract drawings but the work details were not provided or considered in the total Contract. A single line outline wording was given in the Contract Drawings showing that a “retaining wall is to be constructed” while extending the road underneath the Bridge. This Retaining wall is to be constructed just below the below existing bridge and very near to the bridge abutment foundation.
There was already an existing stone pitching available with larger slope. Works involved to do the above varied works were
a) Firstly, remove the existing stone pitching works – this item was also not in the Bill of Quantities
b) Testing the soil stability – Third party testing is to be carried out with the specialists – additional cost to the Contract. Engineer instructed the Contractor to carry out the job.
c) Soil nailing method: Recommended soil stabilization method by the Specialist to stabilizing the existing sloped soil portion underneath the bridge at the abutment portion without disturbing the existing structure foundation.
d) Retaining construction: New retaining wall to be constructed for about 80m length with “L” shape foundation. In front of the Retaining wall, Concrete barrier to be installed/constructed. Temporary works related to do this job was huge. Existing traffic maintenance and protection to the works area with kentledge blocks, more safety features etc., involving additional cost to the Contractor.
e) Road works: existing two lane road to be extended nearer to the retaining wall portion.
Items “a & e” could be covered under the existing BOQ items as additional quantities. Items “b,c & d” would become variation to the Contract.
Engineer was under impression that Contractor must study the drawings and quote the works’ rates accordingly. No additional cost for the items “b & c” should be considered for payment because they are the part of the temporary protection measures while doing the permanent works (Retaining wall). Though the structural details of the Retaining wall was not in the original tender drawings, Engineer had provided the drawings during the construction stage for execution to the Contractor. Engineer’s contention was that Tender drawings were showing the Retaining wall location, though the structural details and Bill of quantities were missed out, it would be the Contractor’s obligation to execute the job provided in the Contract. (Note: Only a single line sentence “Retaining wall is to be constructed” was given on the Contract drawings)
Contractor argues that the Contract value and provided Bill of quantities did not contain the Retaining wall cost. And also, the Contract/Tender drawings did not show any specific structural drawing details. Hence, the works instructed during the construction stage would become a variation to the Contract and subsequent permanent and temporary specialist treatment arrangements’ cost should be payable to the Contractor. Measurements shall be payable as per actual as per re-measurable Contract.
Engineer agreed to pay the Permanent works cost and also the soil nailing method (special treatment to stabilize the soil) cost to the Contractor. Since, these work details were not provided to the Contractor at the Tender stage, though the Contractor had not raised this issue at the Pre-bid meeting stage nor any other competitor at that stage. Hence, additional cost due to specialist treatment which could not be foreseen by any experienced Contractor and the retaining wall works with finishing works (details provided during the construction stage) cost considered for payment to the Contractor.