Holdfast Training Services Trial Blog

This week’s blog will revolve around the services along the western boundary of phase one. The services that are currently in position were put in by Carillion last year as per the agreed design. These services include HV cabling that provides power to the temporary transformers on phase one as well as phase 2. That’s 3.75 MVa of power for phase one alone. The key point to takeaway is the HV cabling is live and being used. The other key service is the foul water, which needs to be in situ to allow commissioning to take place.

Unfortunately (for the client) the as built services now appear to run smack bang through where phase 3’s basement (crisscrossing in and out of the sheet pile wall) will be. Phase 3 cannot be re-designed so the services are going to have to move in order for phase 3 to go ahead. This ideally needs to be done by October this year as that’s the start date for phase 3 (main contractor not announced yet) and it needs to be done whilst keeping the power on to phase 2 and 3. To complicate matters phase 3 is being built on top of the Northern Line extension (NLE), the ground works for which have already started.

Carillion were briefed by the client’s consultant Burro Happold (BH_ two weeks ago as to the situation. Three COAs were presented and the preferred (selected by the client and BH) COA identified for CCL to pursue. We will be back briefing this week. The brief we received with respect to the three COAs considered was:

COA 1 single stage plan

The first option for diverting the Western boundary utilities and drainage is a single stage diversion. This entails providing temporary power generation to the ongoing Phase 1 and 2 construction works. This will enable all of the existing utilities requiring diversion to be removed and constructed along their permanent alignment in one single stage of works. Once complete, the diverted utilities and drainage will be energised and temporary generation/alternative supply will cease. This will then result in the phase 3 sheet pile wall being installed as close as 1m away from buried live HV.

COA 2 two stage plan

To avoid the need for alternative supply and generation to the ongoing Phase 1 and 2 construction works and subsequently piling in close proximity to a live service, a two stage diversion plan was considered. Within the two stage plan, power supply is maintained via a temporary HV diversion within the Phase 3 site, avoiding the basement secant piling wall line. Once the temporary duct alignments are installed, a swift switch over is undertaken at convenient connections to the existing HV network, facilitating the required diversion works to all of the utility networks along the western boundary. Upon completion of the diversion works, piling along the western boundary corridor can commence within the Phase 3 basement. Upon completion of piling, power and water supply can be swiftly switched back to the new diverted utility alignments, with the temporary arrangements subsequently de-commissioned.

COA 3 Tunneled Drainage and Phased Utility Diversion plan.

To avoid the need for alternative supply and generation to the ongoing Phase 1 and 2 construction works, a tunnelling option has been explored for the installation of the diverted foul drainage network to remove the majority of the required diversion via open trench installation whilst maintaining live services. Within this option, the launch shaft at an existing location will be utilised to tunnel the diverted foul drainage route north to a new reception shaft. From this reception shaft, the remaining 30m of required drainage diversion can be installed via open trench installation.

Upon completion of the foul drainage diversion, works can commence on the diverted HV supply alignment. The new HV alignment has been designed to avoid the existing live HV supply where possible, however some crossings are still required (notably at the existing entry and exit to the existing switchgear). In addition, the diverted HV alignment is required to cross the existing Phase 1 water supply. The plan would then be to conduct one shutdown and switch over in a very ambitious 48 hour period.

Chosen COA:

The tunneled drainage and phased utility diversion plan has been selected as the preferred COA for the Western boundary utility diversion works. The key risks associated with each COA are summarised in fig 1. BPSDC and BH highlighted the main drivers behind the selection of the preferred COA as being the costs and procurement risks of temporary HV supply as well as the potential to delay the final commissioning of the Phase 1 building (which requires completion of all associated utility networks) at the end of 2015. As the Phase 3 piling works are unlikely to commence until October 2015, it was deemed inappropriate to consider the two stage plan.

Fig 1. Risk matrix

Thoughts / reflection

Every time I re-read the three options that were presented by BH and the client and look at figure 1 I can’t help but think that the client is placing programme and cost implications well above the safety of the work force who will have to carry out this work. If something goes wrong I’m struggling to see how they will be able to prove that they did everything practicable to remove the risks that working close to HV presents; despite the use of tunneling the chosen COA will still involve new services crossing existing HV with hand digging installation method, which the client wants to keep live, 4 times. This is completely avoidable if either of the other two COAs were chosen. This is going to be highlighted at the back brief to the client, but I very much doubt we will get them to change their mind. The only thing that may throw a spanner in the works is that Carillion policy is to not work with live HV. So the choice of COA 3 may yet still result in temporary generation being required.

Questions for the PET community.

I’d be keen to know the civil’s view on piling so close to live HV. E.g. What happens if piles start to fail? The current plan is to place visual guides at the locations the piles will be driven as we place the new HV cable. This is to give the piling contractor an additional degree of certainty that they are not about to hit a HV cable.

I’d also be keen to know if the M&E community thinks I should be getting involved in this. Obviously the services themselves are M&E base, but a lot of the work associated with getting them in is civils. I think there could be an opportunity to get plenty of B1-3 competency experience. Thoughts?

A drawing attempting to highlight how tight everything is going to be. Orange is new HV, brown is is new drainage. Existing services are greyed out.

For anyone interested in professional engineering content read no further. This blog from myself will not deal with life on site, but is a random tangent of life living as a member of the military in London.

This week on the way home from work I popped into a local take-away (for the first time). Whilst waiting I couldn’t help but over hear three young men complaining about the state of British foreign politics, the theft of other countries resources and the fact they were under constant surveillance from the security services. At this point I should have probably decided to wait for my lamb kofta and walk out of the door. I didn’t. I decided to try and engage with the three young men, to find out why they held the beliefs that they did and possibly have a reasoned conversation / debate surrounding the issues. Unfortunately this didn’t occur; I was confronted by a stonewall. I became slightly hopeful when one of the three mentioned that his thoughts were part of a thesis and who was I to question it? Perhaps it would be peer reviewed and I could read it on publication? No. It wasn’t that kind of thesis. In the end I did have a reasoned conversation, but with a bystander, which was very positive. Having concluded my conversation I left the three young men to enjoy the rest of their evening. When I left them they were still certain that they were being pursued by the security services, that the UK’s aim was to de-stabilise the world and that the September 11^th disaster was a conspiracy theory.

The area in which I had this conversation was Kingston. The average house price is well over £500,000 and the borough has previously been classified as the third least deprived borough in London. The individuals I had the conversation with were articulate in their responses. I suppose my questions and concerns with regards to this encounter are: why do people in such a privileged area hate the country they are from (although acknowledging they themselves may not be privileged) and at what point should such a hatred become a concern with respect to security. How can they be engaged? It’s certainly not by a random chap having a chat in a kebab shop!

Last week I was surprisingly involved in the installation of temporary electrics. I say surprisingly, because at the start of the week I didn’t think I’d have any involvement in this area of the project. Before I go on any further I’ll explain what the current temporary electrics plan is and how it was / is planned to develop.

The temporary electrics subcontractor is Wyse power. There are currently two temporary substations (TSS) set up in a radial to provide power to the site, with a third that and has now been delivered to site and is due to be energised shortly in order to allow a ring main to be established. The HV power comes onto site through an intake substation just off phase 1 and runs under the road on the western boundary before coming into the basement at TSS 1. From here TSS1 is connected to TSS2 via an internal cable. Another cable was pulled at the weekend which will eventually be connected to TSS 3. TSS3 will subsequently be connected to TSS2 via an internal cable allowing the ringmain to be completed. (Please refer to single line diagram).

Single line diagram showing the temporary HV set up.

This blog will deal with the delivery to site of TSS3 and the pulling of the cable that will eventually be connected to the ISS and TSS3.

My involvement in the delivery of TSS3 and the pulling of the cable came about because someone was on holiday and I was apparently best placed / willing to get involved. This is despite being only aware of what was happening and not read into the detail.

The delivery of TSS3

The delivery of TSS3 should have occurred last Wednesday. The plan was simple, use a tower crane to pick the TSS up from the delivery vehicle and drop it directly into its final resting place.

Problem 1? The substation didn’t arrive on Wednesday and the concrete subcontractors were due to be placing falsework in the area where the substation needed to go. Once the falsework was in position there would be no opportunity to directly drop TSS3 in with the crane as the falsework was for a slab pour. Unfortunately for me the Carillion construction team had been told in no uncertain terms that any delay to the concrete contractor was not acceptable. This led to the area I needed the TSS to go being filled with false work and covered over in preparation for a pour.

Solution 1: Placing the TSS as close as possible to where we wanted it to end up and then sliding it into position once the pour had been completed and the falsework had been removed (the TSS isn’t due to be energised for another few weeks, so curing time wouldn’t be a problem).

Problem 2: Wyse power were telling me that the TSS was going to be approximately 2.5 x 2.5m and weight in at around 5 tonnes. This meant that there wasn’t physically a route to get the TSS into its final position from the available intermediate positions.

Solution 2: When pulling the HV cable that would link up to TSS3, pull as much cable as possible into the basement in order to maximise the chance of being able to reach the TSS without having to pay for a cable joiner to come out.

Final solution: In the end the TSS arrived on site and measured only 1.8 x 1.6m and only 3 tonnes. Therefore, more by luck than judgement, we were able to place the TSS into a position that would allow it to slide into its final position at a later date.

Cable pull:

At the weekend that has just gone the cable that will eventually connect the ISS to TSS3 was pulled. This required the power to site to be switched off due the cable being pulled being in a duct parallel to the existing temporary HV power. Getting the HV power turned off is a relatively big deal involving having APs on site as well as the DNO – everything needs to run smoothly! The weekend prior to the cable being pulled preparatory works were conducted (cable pulling pits established) in order to allow the cable pull to proceed smoothly. The back brief everyone in Carillion had received was that these preparatory works had gone smoothly and that we were ready for the cable pull. However a quick chat between the groundworks supervisor and myself highlighted that everything wasn’t quite so squared away. In order to get the cable into the basement there needed to be a hole in the kingpost and sheet pile walls for the cable to pass through – there wasn’t. Fortunately this conversation happened at the start of the week, so it was fairly simple task to get the sheet pile wall cut down (the capping beam has yet to be put in position and will be formed around the cable duct), and a hole cut in the king post wall.

Comments / reflection:

My involvement in the temporary electrics came about because someone was on holiday. In future I need to do a bit more of an estimate as to what might come my way when people are away so that I can better prepare myself.

Everyone knew when TSS3 was supposed to be being delivered, but nobody had highlighted the critical nature of the delivery window – communication is key. A 5 minute conversation between the MEP team and the package manager for this part of the building would have highlighted that the falsework was going in imminently and could have led to the delivery date being brought forward to allow for unforeseen delays, or additional pressure being placed on Wyse power to ensure the delivery date was met.

Wyse power didn’t know the specs of their own transformer – everyone is a middleman. This detail should have been known in advance. In addition I should have questioned Wyse Power’s dimensions more. I could have looked at the dimensions of similar MVa transformers as a reality check on what Wyse Power were telling which would have simplified the issue of getting the transformer in position.

The groundworks contractor knew that the HV cable had to run into the building and that there weren’t any penetrations in the basement wall. Why didn’t they report this first thing on Monday morning? Why did it take a chance conversation to highlight the problem? Talking to people when you’re walking about on site it key to finding out and confirming what is actually going on. Also don’t take what you’re told at face value, question it and check for yourself.

The excitement and novelty of working in a civilian environment is now starting to wear off and the reality kick in. I used to think terms like “military efficiency” and “planned with military precision” were something of a joke given how inefficient and chaotic Army life can often be. I am now coming to realise that I was pouring scorn on these phrases from the point of view of a person who has only ever worked in a military environment and presumed that the drive to make money in the private sector would ensure things ran smoothly. How wrong I was…

“Ask twice a day, every day for two weeks and it should get done.”

This is actual advice that was given to me by my mentor within the MEP department with regards to getting some work out of the Carillion structural team. All that I need from the structures team is an instruction allow some BWIC holes to be cut through the concrete slab and sheer walls for service to penetrations. The holes were on the original drawing but were either put in the wrong place or missed off when the pour took place, so it shouldn’t take much work for Buro Happold (structural consultant) to approve the holes. Having read Nick’s blog from earlier in the year with regards to civilian’s interpretation of tasks, and from my own experience of working with civilians as a staff officer I was aware that a simple email wouldn’t suffice. A conversation with the appropriate member of the structural team, email and additional conversation later I was confident that the task would proceed. This is when I was given the advice in the quote above. As my mentor predicted a week has passed by and various excuses have been given, the problem passed around the structural team and all attempts to pin down a date for a solution been dodged – for what should be a fairly straight forward task. I am now thoroughly bored and embarrassed with the daily grind of asking the same question (although this appears to be the SOP here) and have decided to take a different tack – apply some military process to the problem. I’ve managed to get the buy in of the structural team to using a simple tracker so that we know what needs to be done and produced a request for work template which specifically details the works needed on one piece of paperwork as opposed to several emails and drawings. Hopefully this will clarify what needs to be done and make the job of approving the work easier for the structural team so that they will turn it around more promptly. We’ll have to wait and see….

Rose wasn’t too impressed when she found out how Carillion do business.

Although the novelty is starting to wear off I am enjoying phase 2. Life in London is great – I’d definitely recommend it as a location for anyone on next years course if there are any jobs available. I’ve got a quarter in the Keep, Kingston-Upon Thames. The quarters aren’t going to win any awards for architecture and certainly don’t blend in with the Victorian town houses, but they are very nice once you’re inside. Richmond park is a 10 minute walk away as is the Thames and it’s possible to be in central London in under an hour on the train. I am currently getting my PT sessions in by cycling to work most days, which at 50 minutes each way is a quicker commute than the the train by about 15 minutes.

One of the stags I regularly pass on my cycle into work.