Holdfast Training Services Trial Blog

I’ve received a bit of a random cry for help that I could use the advice of the collective group for….

I have a mate who is now working out in Africa for the Halo Trust doing de-mining in Angola. The camp that he is running is basically built on sand. No problem for the buildings but the vehicles they use to get to the de-mining areas are struggling. He’s asked me what he can do to improve it (his first mistake could be asking for my help!).

I’ve attached the some photos he sent me below. He has a limited budget to improve the area (it being a charity that he works for) and is looking for the best “sticks and string” answer. The camp needs to last at least 5 years and the rainy season is November to end of March.

The town he is in is called Cuito Cuanavale in Kuando Kubango province Angola. You can google it and you’ll find a small airport, his compound is about 2.5Km NW of the airport. He’s up at 1250m above sea level and where he’s seen some exposed strata by the river it is all sandy soil with no rocks.

To find out a bit about the soil I got him to drop some of the material into a glass of water and see what happened – the photo below is after 3 mins. There is a sketch above that he sent me of the layout. The key areas are the vehicle park and the areas that the tractor towing the water tank on needs to get to – so a bit of a one way circuit around the edge would cover that. He should be able to get his hands on a roller from another de-mining camp without too much bother and maybe a local JCB for a short period.

Any and all (sensible) suggestions welcome!

There have been quite a few developments since my last blog, the most recent and dramatic being the 200mm of rain we had in about 48hrs, but more about that later. My concrete thermal tests have finished on both the 40MPa and 50MPa mixes and happily they both passed the temperature test reaching 62oC and 71oC respectively (the limit was 75oC). Happy days I thought, however this does not fit with a computer model that the Project Manager had commissioned from a consultant. He is concerned that the 2oC difference between results will mean we go over the limit in the real pours. I’ve now spoken with the chap who did the computer analysis to see what the score is, and he confirmed it will be fine. This was what I had thought all along, plus when our batch plant is finished the agg temp will be lower than that in the trials (shaded stockpiles and cooled water passed over the coarse agg, which wasn’t used for the trials). CIRIA report 135 was very handy in giving guidance on temperature reduction for larger volume pours.
The temporary works for crossing scrubby creek were progressing well with the temporary bund 2/3 complete when the environmental rep for the designers drove past on route to a meeting. Her passing comment “I don’t think you’ve got a permit for that” threw the cat among the pigeons. We did have a permit, issued by them. The reply was “we thought you’d just drop them in” . What she proposed for us to “just drop in” are 14 x 2.1m diameter, 15m long culverts that need to sit on a bed of engineered fill into a creek filled with water. The lack of consideration given by the designers to how we would build a fairly critical part of the facilitating works astonished me. Has anyone else had any similar occurrences?

I met with the steel fixers for this job and now have a number of RFIs to submit to try and change the design to make it possible. I found the note from the designer rather amusing – pilecap reinforcement not shown for clarity – probably because it isn’t possible to fit it in! Some changes are possible to make it work, but in some cases it means a splice and we will end up out of pocket for the extra steel. The change will hopefully make prefabricating the steel easier, and the saving in time may outweigh the cost of the extra tonnage. In the same meeting we also discovered that the steel fixers were using pre-construction drawings from the tender phase. Not good. The correct drawings have now been issued from the document management system (incite) and hopefully we’re back on track. I think this arose from the steel fixers not having been contacted since the tender phase, as it is the contract has still not been signed.

Back to the weather. The site has gone from pic 1 to pics 2 and 3 in just a day. This is not so good for the program. As this is a fairly normal rain event (less than a one in 1 yr rainfall) there will be no extension for time and no extra costs for John Holland to claim as this is not unforseen. As I see it John Holland gambled with putting fewer rain days in their program than all the other bids, who are likely to have included substantial costs for delays due to rain. The largest of those costs will be the piling subcontractor, who will charge $30000 a day if we delay without a minimum of 2 weeks notice (the cost drops to $5000 a day). There is no pain/gain share in this contract so as we were facing some heavy costs the plan has now been flipped on its head. Instead of starting at the southern end of the bridge and heading North we’ll start at the North and head south. This gives us about 8 to 10 weeks work to get the rest of the access track completed and the whole site linked up. Why this wasn’t con-planned before I don’t know.

Paperwork for the concrete works continues, and I’ve talked down some of the bids from the concrete pumping companies with a view to awarding that contract next week (still have to finish the tender evaluations). The first piling rig is also due to be transported here next week along with the additional cranes and associated gubbins.

Phrases learnt this week:
“Fair dinkum” – straight up or fair enough, “no joking”
“ fair suck o the savaloy” – same as fair dinkum
“eat the arse out of a low flying duck” – to be rather hungry.

Steel buffs unite!….I’m trying to decipher why the structure has used I-beam columns throughout the site and then occasionally SHS columns (generally on the outer columns).  In addition, the ground floor horizontal cross bracing uses SHS rather than I-beams.  On questioning the contractor – who were not the designers – they could only assume it was for blast protection.  Maybe so, but I’m not convinced as it’s also used within the building for diagonal bracing.  Thoughts?

With the sudden onset of Spring, the contractors are making hay whilst the sunshines…at least a bit of it anyway.  Concreting has commenced once more, although one would have anticipated more being laid in the time available.  It would appear that the subcontractor thinks it cheaper to have less manpower and work longer, rather than swarm the site and lay more concrete in one go…once again, we can only speculate, it is the contractors baby to manage as they see fit and from the last schedule review we held with them they guaranteed us they can meet the deadline within 3-days….a big shout!  Precast concrete curtains have started to arrive on site and should hopefully start to be put up next week.

I still haven’t got access to the USACE system.  They have reworked the application process for ‘foreigners’ and I’ve just found out that I’m the guineapig…the problem is that no one knows what to do with this guineapig when it comes to IT; frustrated to say the least.  Nevertheless, I’m trying to make best speed of what I can do without access so am also now undertaking reviews of upcoming construction of two main access control points to the site we are on…encompassing a large amount of environmental, drainage, wetland mitigation as well as interesting security and VBIED mitigations.