Saturday, February 18, 2012

What is Construction Variations

Any items not in the original BOQ considered as variation.

Variations Originated by client

  • Requirement increases
e.g. By increasing the length of the road in order to fulfill the requirement of the road user (client change)
  • Change in mind-choice
When the client chances his mind to go for higher standard cost overruns occurs
e.g. The original DBST Standard for the hard shoulder changes to Asphalt concrete.
  • Change in mind-forced
The client charges the scope of work due to the pressure from the respective political authorities.
e.g. Asphalt concrete surfacing instead of other type of surfacing method.
  • Poor / vague brief by client
When there were short coming in briefing the consultant by the client, leads for the cost overruns as the scope of work has to be changed during the implementation stage.
Inadequate time provision to prepare tender documents
When time provided for the preparation of tender document is short, it leads for many short coming and create problems during the implementation of the project. This will lead for cost overruns.

Variations Originated by consultant

  • Lack of co-ordination among design team
Lack of coordination among the design team may create problems during the construction stage.
e.g. In allocating space for different utility services proper coordination among the different design team is vital, otherwise construction of one utility service may cause damage to other utility service which will lead for abortive work and leads for cost overruns.
  • Design changes
In road construction design Changes is consider as a vital element which changes the cost of the entire project.
e.g. In designing the pavement of the road, strengthening the pavement with aggregate base coarse replaced by binder coarse leads for cost overruns.
e.g. When curve widening on a road is taken up during construction which was not included in the original designs, invariably increase the cost of the project.
  • Defects in design
Detect in design leads for additional need for remedial measures. Defects in design occurs due to improper design details, improper specification..etc. e.g. For the hard shoulder construction first coat tarring on a ABC surface will not survive for a longer duration. This has to be rectified by carrying out SBST or DBST in the some contract in order to prevent further damages.
  • Inadequate consideration of design
Provision for super elevation on the road cross section is in the reverse direction, needs rectification. This will leads for increase in cost of the project.
Incorrect assessment of brief
In correct assessment by the consultant on the brief of the client will lead for variation this will lead for cost overruns.
e.g. Non provision of built up drainage on a high rain fall area (Hilly Terrain) leads for introduction of built up drains at the implementation of the project in order to prevent any erosion.

Defects in BOQ

When there is a change in scope of work the BOQ amount will get change. This leads for cost overruns. The reasons for the defects in BOQ are
  1.  Short coming in the initial taking off Quantities
  2.  Scope of the work is not properly identified.
  3.  Arithmetical mistakes in the BOQ
  4.  Outright omission of the works

  • Improper specification
In proper specification will lead for damages. To rectify the above damage precautionary methods will have to be introduced.
e.g. Construction of build up drain in the hilly terrain where seepage water is very heavy due to rock earth separation. This has to be rectified by introducing sub surface drainage and then build up drain.
Over specification may also lead for cost overruns as the required material at a higher specification has to be imported or brought from a distance place which leads for extra transport distance and high cost.
  • Shortcoming in drawings
Due to the short coming in the drawings changes of final Qty which is different from the original BOQ. This causes change in cost.
Shortcoming in other contractual documents
Short coming in the other contract document will lead for extra cost. e.g. Formula and indices used for the calculations of the price fluctuation has to be carefully in cooperated in the contract document slight omission on the usage of correct indexes will lead for extra cost.
e.g. ICTAD indices used for calculation of foreign currency fluctuation is incorrect. Then it will lead for cost overruns.
  • Errors in documentation
Errors in documentation will lead for cost overruns.
e.g. The decimal place get changed may lead for change in Quantity in a significant level. During implementation stage the error has to be rectified and lead for change in cost generally, it will be an increase.
  • Inadequate site investigation
This will lead for cost overruns.
e.g. In the initial investigation stage when the soil conditions are not investigated properly the construction of sub grade has to be changed during the construction stage, generally soft soil treatment is a very expensive item in the entire road construction work.
Change of scope leads due to inadequate site investigation will lead for extra cost.
Improper post tender correspondence and negotiation
This results for a increase in cost of construction.
e.g. The rates agreed in the important items has to be done very carefully, any mistakes made in the negotiation may lead for major variations. This naturally leads for increase in cost.
In the negotiation stage, if it was agreed to have the possession of site 100% when the construction process starts and there was a delay in handing over of 100% site when the project commence. In this situation the contractor has the right to make a claim for late possession of site.
  • Poor bore holes and exploratory tests
When this is not done properly the designer can not decide on the design requirement, when there is a short coming bore holes exploratory then It has be rectified and this changes the scope of work and leads for cost overruns.

  • Inadequate contract monitoring and management
Contract management is a very skill and continuous process. Any impending problem has to be correctly forecasted and action be taken in order to reduce the cost and problem in the implementation state.
e.g. In the implementation stage the consultant has to make sure that, the mobilization advance paid to the contractor has been correctly utilized and mile stone intended was properly achieved.
Setting out based on incorrect data provided by the Engineers
The above will lead for abortive work and lead for the need to have that rectified this will lead for extra cost.

  • Variations Originated by Unforeseeable events
Restrictions due to existing utility lines
There are lots of restrictions in the construction activities due to the existing utilities. Generally the existing utilities will have to be shifted to a suitable safe location in order to avoid any future damages. At times when the utility services are lying under ground the method of construction has to be amended. This will reduce the efficiency of the contractor and results extra cost.
  • Poor soil condition
Poor soil condition will lead for a different type of Sub base construction.
e.g Sand pilling or rock filling these will cause extra cost to the client.
Flood & Land slides
When Flood & Land slides occur during the construction stage, these will cause severe damages to the road surface, materials, construction equipment and delay the construction activities this will leads for cost over runs.


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