Case Study - Monitoring Works Flashcards
Why have you used an Option C contract for the I&M works and not an Option E contract?
- The Contract was in place prior to my involvement and was issued by the I&M Commercial Lead who is the project director.
- When the design has not been fully completed but a relative outline is present to execute the contract
- To incentivise a specialist subcontractor such as the I&M subcontractor to provide innovative solutions that facilitate cost efficiencies to keep costs under the target cost.
- When there is a known that the design will develop through the construction life span of the project
What is the mechanism of Option C contract?
Pain-Gain mechanism which is calculated based on the Target specified during tender. The percentage pain and gain is decided between the parties and stated in the contract. If the defined cost is above the target, it is pain where everything up to the target cost is paid to the subcontractor and everything above the target share based on agreed percentages. If it is below the target, its gain or saving where all the defined cost is paid and the saving is shared based on agreed percentages.
As a competent Contractor was the contractor not aware of the health and safety risk of working near railway lines?
- The Contractor was well of aware of the risk.
- The original scope of manual monitoring works was a rudimentary design which did not require extensive monitoring and could be provided without entering the railway line.
- Unfortunately, throughout the construction phase there have been multiple transitions of construction, demolition and utility diversion changing the landscape and consequently the monitoring requirements.
- Once the tunnelling works progress through Euston the project team will anticipate further inclusions of monitoring at deeper depths.
- In addition, the assets and surrounding buildings were not in the stated condition in the survey and ground investigation reports carried out by the enabling works contractors thus increasing monitoring requirements.
For Key issue 2 Damaged Equipment why was demobilisation prior to construction activity considered to prevent the cost impact of the damages?
- Both the Contractor and the Subcontractor considered this option during the risk reduction meetings as a form of mitigation to the damage.
- The Site Team had to however consider other factors that would affect such as delay to the programme of the main construction activity, congestion of persons on site, cancellation of possessions.
- Delay of the main construction activity meant massive cost overruns for standing time. Cancellation of possessions meant that the demobilisation would have to happen while the construction activities are happening. This means that there will be multiple interphases and congestion on site posing the risk to health and safety and potential fatalities.
- The cost of the equipment – specially inclinometers were not significant and can be absorbed by all parties. The demobilisation was only considered for equipment such as ATS expensive.
Why was the contract issued without deeper consideration of the design/ scope of works?
- The Employer required the main works to commence by a certain Start date.
- The monitoring works is necessary to be in place before the construction works commence and runs parallel to it.
- All the investigations were carried out by the Early Works Contractor that fed into the design.
- There was sufficient design to commence the works therefore the contract was issued.
- For a complete design the works must commence as the design will develop and change with the changes happening on site.
You have mentioned two monitoring techniques manual monitoring, and automated total stations. Can you describe them and why they were used on the project?
- Manual monitoring: a team of 2 skilled surveyors that use pins in the ground, levels that take readings.
- Automated Total stations: A highly sensitive total station with multiple prisms installed in locations around the total station. The total station is attached logger that transmits data to remote software that can be accessed by the monitoring team.
- The monitoring is required at 1m settlement contours of the site boundaries and at specified depths within the site boundary. There is specified equipment that monitor ground movements. If thresholds/ triggers are reached works in and surrounding areas need to be stopped to investigate.
You have mentioned that you have considered contractors insurances, why were the damages not considered under subcontractor insurances?
The damages were not solely due to the subcontractor, they were also due to other subcontractors which was a risk retained by the Contractor and Main contractors or third parties such as the rail operator which was a retained risk by the Employer HS2 under the main contract.
You have mentioned that you have added a direct fee of 20% how did you get this?
It is stated in contract under Contract data part 2.
what are the amended clauses mainly?
For the Main Contract between Employer and the 3 Contractors in Joint Venture - 60.1 the Compensation Events. These are amended Annexure E which is additional Compensation Events or amendments.
What are the major risks in these scenarios or the buildings in these assets during your project?
The surrounding building can have uneven settlement, minor cracking, damage to building or complete collapse with people inside causing injury or death to the public.
What is settlement?
- The downward movement of the ground caused by the load consolidating the soil below or causing displacement of the soil.
- Settlement in this scenario refers to the downward movement of the ground due to excavated space for tunnel construction.
- Note:
- Consolidation: the process in which the volume of a saturated soil decreases due to applied forces or stress.
- Compaction: the practice of applying mechanical force (by the use of plant such as vibrating plate, trench compactors, combination rollers) of compacting to densify a soil by reducing the void between soil particles.
What are the different ways to deal with it?
- On the Project, during enabling works a baseline has been established through Ground Monitoring Assessments. Throughout the construction works the I&M subcontractor progressively monitors the surrounding buildings and assets within 1 m settlement contours to the site to track changes to the baseline.
- An Example would be the Park Village East Wall which has displayed a tipping settlement. This was due to the excavation of the ground adjoining it. A technique used to prevent the tipping is to drive helical ground anchors into the wall at a specified angle from the side of excavation and a Counterfort retaining wall from the other side. These will be possibly removed once construction of the specific assets that will be adjoining the wall.
- Underpinning of identified buildings on Park village East which are directly affected by the tunnelling works below. The Underpinning methods is yet to be decided but the two-option considered are mass concrete extends the foundation or mini piles with a needle cap.
Were you involved in managing risk? If so, how?
Yes, when the subcontractor sent Early Warnings, I would liaise with the Site Team and the Construction Lead to organise risk reduction meetings where I would provide my commercial expertise in estimated cost to facilitate the Construction Lead’s decision making of the suitable solution for the works.
You mentioned that the reasoning behind change of scope was due to the COSS being late and cancellation of possessions, were there mitigations in place to counteract this?
- An additional COSS (Controller of Site Safety) was put in place in case of late arrival specially during COVID, Brexit, Holiday period, where there was a possibility of no show to secure resources. The resources need to be booked a month in advanced to ensure that they are available before other Contractors book them.
- Cancellation of possessions was mitigated by utilising already booked possessions for the Main Works. This would come with additional risk as multiple interphases will be working in tight spaces. In certain cases, Possessions need to be rebooked and the delay cannot be mitigated as the nature of cancellation is due to trains being late or trains breaking down which was very last moment.
If you descope the works wouldn’t that mean that the contractor will not be meeting their obligations?
The obligation under the main contractor is to provide monitoring readings against baseline Ground Monitoring Assessments (scheme design or strategic brief). The method proposed to carry out the works by the Subcontractor is manual monitoring works. The progress of Construction activity has brought additional requirements materialising health and safety risks thus a change of methodology was proposed. The Contractor is still meeting the obligations under the Main Contract. It is considered as a change of methodology a descope and rescope rather than a complete descope of works.
What are the amendments on your contract?
- The Main Works Contract has many amendments but the main focus is Clause 60.1 the list of Compensation Events. Through the inclusion of Annexure E (Additional Compensation Events) the Contractor has limited their liability by stating specific items that are out of their control that can lead to increased costs such as Assets not in the state conditions ‘not in good condition’ as per the works information.
- The subcontract has been amended through the addition of specific secondary clauses such as X18 limitation of liability and Z clauses that include any additional works to be instructed under same contract as a compensation event and that require the Contractor to provide notifications in the event of changes to Third Party agreements.
What are the different prelims works in your contract and how are they classified?
- Preliminary works are the preparatory and supporting works that the Contractor requires to carry out the main works but do not form part of the main works.
- Examples are such as Staff Management, Ground Investigation works, monitoring works, Utility works, Traffic Management, Site Accommodation and Hoarding.
Give examples of each and demonstrate how you deal with them on daily basis as part of managing the package?
- Ground Investigation is an option A subcontract where I track the progress of the contract scope against the budget. Additional Scope outside the contract scope is issued through compensation events. (Traffic management, site accommodation is also option A subcontract)
- I&M Subcontract requires the checking of all labour and plant sheets, invoices against works carried (liaising with the Site Team) out to establish defined cost. Any additional scope outside the works information is issued as a compensation event changing the target of the contract.
