Holdfast Training Services Trial Blog

I have finally got my foot in my work boot and hobbled round site this week to find an exciting progression at the end of the basement.  The diagonal props are in, the excavation completed, piles have been munched and the walers, bracing frames and thrust blocks are going in.  To add to the excitement I keep hearing concerned conversations in the office between the basement section engineers about how the sheet piling has moved 20mm and is only allowed to move 5mm more and that a thrust block has been cast touching one of the piles and may need to be ripped out.  All the talk about deflections, passive forces, failure and other key engineering terms attracted my attention and would make very interesting work if I wasn’t OIC drains, power, water, comms and road!

Back in the world of utilities, this week has been dominated by the incoming HV cables and Battersea Park Road Wall.  2 weeks ago it was decided that the electricity providers SSE were to bring the incoming ducts to the HV substation we had built.  Last week they decided that they didn’t fancy burrowing under the brick wall and the Employers Agent T&T decided to send us a Request For Change at around 1800 Hrs the day before Good Friday.  The wanted us to dig a trial hole to find the foundations of the 2m high antique wall, cat scan the area outside the wall on the footpath and then tunnel under the wall to meet the incoming service trench.  I started looking at this on Tues and realised that their new proposition would remove manpower from our Network Rail Access Road work, involve getting permits to work on the footpath and then require a specialist to look into supporting the wall whilst tunnelling underneath which would also involve more TW designs, RAMS, etc.  I spoke to our project director about it and he pulled out the big guns and sent it back saying it will take us 6 weeks (the power needs to be on by 1st May!). So this made my Client Utilities meeting extremely fun yesterday which I was left to chair on my own by Carillion.  I went for the good old simple squaddie approach and suggested knocking the wall down as part of it was getting knocked down already and after much debate everyone decided that was probably the best plan.  I then went out with the Buro Happold Design Engineer and we started to formulate a plan to give to the client.  With things going seemingly well the installer from SSE threw a spanner in the works today saying that he was still working to the first revision of the drawing (we are on number 8!) and that he must bring the cables into site at 45 degrees not the 90 degrees.  Cue another 45 minutes looking at the wall debating the best way to do it and not mess up the water incoming water supply or the yet to be built comms pits and ducting.  I think we now have a very inefficient solution to knock down a part of the wall, bring the HV in and worry about the water and comms. Here is the wall of doom, HV was meant to come in on the left near the substation, then water in the centre and comms on the right. Now the HV is going to come in on the right, go straight over and next to the water (to make it nice and lukewarm for everyone no doubt) and comms TBC!

So why is getting things through a wall so difficult? Well my meeting uncovered a few issues; firstly a gap in scope where Buro Happlod have been contracted to design to the meter/substation/comms pits near the boundary wall and the incoming supplies were design by others. Secondly the client’s agent T&T have failed to get the utilities companies on board early enough to detail how and what needed to be done to get their kit into the site. Thirdly, Carillion and Buro Happold have been revising drawings but not as a request for change from the client which is why the utilities companies are 7 revisions behind. So despite their being no technical engineering issues I have been baffled by contractual language and experienced first hand the great arguments behind who will eventually be to blame/will pay for it when the power doesn’t go on in time!

Well I made it back to London this week and back to work on Monday. The foot is on the mend and I have now progressed to the B3 Cbt Engr post final exercise hobble! All of my x-rays have now come back fine and I am now encouraged to walk but it is still a bit uncomfortable. It takes me twice as long to get to work as I have to walk slowly to the bus stop and site office but hopefully it will be back to whacky races on the bike again soon.  At least my foot looks like a good bit of engineering now with it’s 3 titanium bolts!

I am now office bound for a few more weeks until I can squeeze the hobbit foot into my work boots but I am still covering the utilities installation.  I have picked up a few technical issues that need sorting out before we can finish off our drainage.  We are planning to pipe-jack a 450mm concrete pipe 70m under Battersea Park to the mains sewer.  Our sub-contractor (O’Keefe) have a sub-sub-contractor (Perco) lined up to do the work and as far as we were concerned they had a plan at least pencilled in.  I was a bit concerned to see an email from Perco asking O’Keefe to clarify the ground water level as the latest and closest borehole information didn’t show a GW strike in the first 10m yet another borehole further up the site hits water around 3m BGL.  I found this latest borehole data very unusual as around 20m away we had been striking water at around 3m in the drainage trenches and it was p*****g in!  So today I have been doing my own desk study and gathering previous borehole information that is on Aconex-our data sharing site and getting the latest data from the client’s representatives.  Low and behold all previous boreholes along the south of the site strike water at around 3m BGL either in the River Terrace Gravels or Alluvium Clay above the gravels.  The area at the south end of the site is a bit unusual as it was a reservoir with filtration beds in the 1800’s and the back fill has been a variety of materials.  I think the latest borehole didn’t record the groundwater accurately for perhaps 2 reasons: they were using water between 1-5m to lubricate the cable percussive borehole machinery, or the fact that we were dewatering our drainage trench around 20m away at a rate of 7L/s.  Either way it doesn’t look like a good borehole to use for design (John-triangulation I hear you say!).  I am also a little concerned that Perco have said that they would have problems conducting pipe-jacking with a heading in wet granular soils due to the likelihood of ground loss.  I have put my findings to the senior engineer at Buro Happold who has been designing the drainage and hopefully he comes back with some advice on the design borehole that Perco should be planning the works to.

Around the rest of the site progress has been made and here is last months time lapse video:

http://vimeopro.com/user25873713/battersea-power-station

In the Cam 96 video you can see my retaining wall for the road going in by the railway arches.  In the bottom left the cofferdam for the pumping station has been excavated and propped using a Mabey prop system and finally the concrete rings have gone in but I missed that excitement.  In the top left corner John would be getting excited with the props, waling, thrust blocks and excavation of the cofferdam, so far the sheet piling has moved 20mm and there is only 5mm more allowed.  We are not sure how accurate all the monitoring measurements are though because someone has hung a water pipe on the wall using the survey targets!  The piling rigs are still working hard and the sub-contractors are still constantly arguing over pile mat handover and areas to work in.

Well I haven’t blogged for a while as I have been at home feeling sorry for myself after my other foot operation.  I have now progressed from crawling and hopping to now hobbling around the flat and I am being a bit more productive.  The first week involved co-codamol induced tiredness and my foot feeling like it was full of molten lava so I didn’t achieve very much except a few odd jobs and lots of watching Grand Designs, Homes Under the Hammer and Building the Dream.  Just to prove I haven’t been off skiving here is the foot after a week:

My highlights of the week were the arrival of the postmen and Ocado delivery guy.  One of which bought me a very exciting get well present from a friend.  Helping to maintain my engineering practical skills and entertaining me for 2 evenings and 1 morning, I give you the Lego Campervan:

Hours of entertainment and great attention to detail inside it.  I am glad the age was 16+ as I was surprised how long it took me!  The engineering challenges were organising my stores area without taking up my whole living room and not lifting it up by the roof which falls off under its self-weight!

I have also been keeping an eye on my Carillion emails and it doesn’t seem like I am missing anything too critical.  The most exciting email has been regarding the banana shaped HV slab.   The plan was to knock the wall to Battersea Park Road down, install a GRP housing on the slab for the substation, insert the substation equipment into the housing and connect the cables.  However, the Battersea Power Station Development Company (BPSDC) who are the client have been unable to knock down the wall as TFL will not let them close the footpath.  The doors of the GRP to the substation  were meant to open outwards to where the wall was but seeing as it is still there the plan had to change.  Scottish and Southern Electric (SSE) have now decided to get a different GRP housing which has 2 sets of doors on each side.  It sounded like a good plan until I read the next email which said that the housing was bigger and would overlap the slab by 400mm!  So the client has requested that Carillion extend the slab to fill the void.   It sounds like it is going to be a time consuming and expensive work around for not being able to knock a wall down when expected.

Tomorrow I am back off to hospital for my X-rays and hopefully I will be off crutches by the end of the week.  If all is well then I will be back to London on Sunday to go back to work on Monday.  It will probably be another 3 weeks before U can get my work boots back on so I will be confined to the office for a while.  I hope to do a bit of talking to the H&S manager and the Environmental and Sustainability person.  I might also try and get a day shadowing the Temporary Works Designer for Carillion who works at their main office.  Are there any other useful things I can be getting on with before they pile my desk with paperwork and tasks that nobody else wants to do?

On my arrival back to London on Sun night, I realised the city smells.  A weekend of fresh sea air and sunshine is soon forgotten when you appear into the smog of Clapham Junction!  Again Monday started well with a visit from the Carillion Surveyor for a bit of QA on the drainage.  He was able to find that some of the surface water drains are up to 500mm out of place in plan, just what you need when you still have water, HV and Comms to get in there!  The next visit was from the Scottish and Southern Electricity (SSE) Engineer who is coming to fit the HV equipment.  I was pleasantly surprised to hear him say the last week’s banana shaped HV slab was actually alright, but not so happy when he told us the other temporary sub station was meant to have cables coming out of the back.  Typically this was the one that was right up against the Network Rail fence that took me about 2 weeks to get the fence moved and construction approved.  Cue some quick thinking, a re-arrangement of the layout, a quick design change and another call to the Network Rail guy to get him to accept the change asap.  Today the slab was poured and so far is looking much better than the first one!

This week’s most time consuming job has been checking RAMS: Risk Assessments and Method Statements.  Each person that comes to work on site must submit the RAMS to be checked by Carillion.  Today I must have spent about 2 hours sat with the SSE Engineer trying to explain what our M&E manager meant by making his RAMS site specific rather than 71 pages of his ‘how to install earthing’ instruction manual.  We now have some workable paperwork that complies with Carillion’s standards.

I have also established that sub-contractors are a cross breed of car salesmen and lawyers.  They try to convince you that what they are offering is great and just what you wanted, despite being totally turd that a 10 year Sapper could do blindfolded.  They are also there to totally undercut other car salesmen and they promise to give you the best offer.  They are like lawyers because everything that is said is taken as gospel and words can be twisted to suit them.  Today’s 4Cs meeting turned into a great debate about how they were going to put a footpath along where the drainage has got to go.  There isn’t enough room for the barriers to be 2m from the edge of the excavation and any temporary works will require a design from our Carillion Temp Wks Designer who will probably have a 2 week turnaround.  If I am not too busy reading RAMS as I spend my Saturday working I might see if I can design a barrier myself and send it to him to see what he thinks.

The highlight of my week was definitely being put in charge of the ‘Holes Register’.  Initially I was convinced that it was a wind up but I then found on the system the ‘Daily Hole Inspection Sheet’.  I had already warned off the subcontractor that each manhole cover needed a ‘Hole Below’ warning painted on and I was impressed to hear that it had been done.  On my wander around to check progress on the drains I spotted one of the painted covers to find a knackered piece of ply wood saying ‘Blow Hole’.  After laughing my head off in the middle of the site I sent the sub-contractor this great picture and Carillion’s guidance on how to cover a manhole.  I can now understand the need for such strict H&S rules!

Thankfully I only have until Wed morning on this task until my next foot butchering session in the afternoon.  Roll on 2 weeks on my couch at home by the seaside (not that I can get to the sea on my crutches).  I will mostly be watching back to back Sherlock episodes and Pulp Fiction so I can understand John’s joke!

Here’s the time lapse for the project so far.  It’s John’s dream job: sheet pile cofferdam, props, wailings, dewatering, excavating, piling mats and piling!  My drainage are the ones digging a straight line by the railway arches!

http://vimeopro.com/user25873713/battersea-power-station-progress-videos

This week did not start well when South West Trains decided to terminate my train at Southampton at 9pm on Sunday evening due to an electrical failure. Having learnt from my last epic 10 hr train journey where a tree landed on the train roof a few weeks ago, I decided to promptly get on the next train back home to Bournemouth as there was no sign of anything going north.  The 5am start on Mon to get back set me up well to write a great complaint letter to the train company anyway!

After finally arriving on site the day could have gone one of two ways depending on the progress with the HV substation slab and the tapping of the old pipe.  I was happy to find that both tasks had been carried out but when I looked into them further I realised that the day had started at 5am as it meant to go on: a nightmare!  Firstly, I went to have a look at my concrete slab and found this:

A banana shaped trench that was meant to be straight!!  The as built survey showed that the trench was 47mm out about 3/4 of the way along the first picture.  Apparently the formwork had got wet before the pour and as a result it had warped or not been strong enough.  It is unlikely that the pour rate was too fast for the formwork design as some parts had deflected into the slab.   A more likely reason was crap carpentry from the two cowboy builders who won’t be working on site again!  The subcontractor may get away with it if the electrical company don’t have a problem with it when they visit next Mon.  Otherwise I will be producing a non-conformance report next week for some remedial action to be taken.

Then there was my old pipe that broke the utility guys tapping drill last week.  We excavated a straight part of the pipe and they were finally able to tap it and it was found to be an old gas pipe, not full of gas but full of water.  The drainage gang took the bung off and spent an afternoon letting it drain and pumping out the water.  A few hours later they gave up as it didn’t seem to be draining-back to the drawing board!  Plan B involved hiring in a water tanker pump vehicle to hopefully pump it out.  2000 litres and 2 tankers later they were finally in a position to break the pipe and carry on.  The south drainage area has now been nick named the aquatic area and they will have more problems to come when they encounter the run-off from the wheel wash that is also turning part of the site into a swimming pool.

The week ended in a slightly more positive note with a free trip to the Beyoncé concert at the O2 arena.  Our groundworks sub-contractor’s O’Keefe own a box there so they invited the construction team for a night out.  With free drinks and food and a great view it was a great night out.  However I have learnt that drinking on a school night isn’t much fun when you get given a list of RFIs to check if they are closed the next morning!