Holdfast Training Services Trial Blog

Time for an update on site progress at Australia 108.  Lots of progress on site this week.  90% of the piles caps are complete and we have begun the excavation to Basement Level 1.  We are 38 days behind the site program due to various issues and delays with the piling as well as lost days due to weather.

The most recent big issue is one of out-of-tolerance as-built piles.  The Australian Standards allows for 75mm tolerance however due to the risk in the piles, the designers have allowed for 150mm.  So what do you get when you discover that a 2100mm, 80MPa pile with a design axial load of 111.6MN, moment of 16.5MN and shear of 2MN ends up being 401mm out of position?  An increase in moment to 49.9MNm; the design effect has greatly exceeded the design resistance of the pile = big problem!     The engineers are currently looking at rectification methods involving large transfer beams in lieu of individual pile caps and transferring the addition moments generated to the other piles and the core if necessary.  It is estimated to be at a cost north of AUS$400k = 200GBP +.  There have been 12 piles over the specified tolerance and with the exception of one, the others have luckily had adequate capacity to resist the additional moment due to the redundancy in the pile with minor rectification measures being introduced to the ground beams.

My TMR is looking into the risk management strategies of deep foundations so once I’ve finalised it, I will post a very abridged version highlighting our issues and probably causes.  I know a few of you are soon to commence piling in your projects and can benefit from hindsight of some really simple errors that have been made on this site – most of which could have been easily avoided.

Here are a few pictures to keep you up to date with progress on site.

View to the East

View to the South – excavation of the core piles has begun consisting of 16 x 1800mm king piles with 600mm dia CFAs between

View to the West – secant retention wall to protect a 60 yr old heritage facade at the northern end of the site

View to the North West – northern retention wall and one level excavation

And for those of you with beady eyes it will not escape your attention the 3+m high vertical face of the southern end to the excavation. Fine grained soils, 30t excavator rolling back and forth on the top of it and no retention or batter.  We’ve also had a lot of rain recently (for Melbourne anyway – the news reported a taxi getting flooded out to mid-point of its wheels!!!!!)  I have raised this concern to the powers that be and it has already been mentioned to the subcontractor who have chosen to continue as it – because they do it all the time.  BMC are allowing them to continue (cynical view – because any changes will slow down progress.)  They have instigated no one to walk at the foot of the wall yet people are still walking at the top of it.  I’m astounded that they will stop work for the slightest speck of rain because of the potential hazards created, yet they will let people walk along the top of an unprotected excavation.  And they are constantly telling me how at the forefront of H&S they are.  Barking!

Progress on 12/5/16

Progress of 13/5/16

The most recent work strand I’ve been involved with at BWL is the re-modelling of a private hospital in Reading. The hospital is owned and run by Circle who have a long term relationship with Bryden Wood Ltd (BWL). The requirement to re-model is based on Circle wanting to go into a joint venture with a German health care provide called Vamed. The plan is to hand two of the four floors of the existing hospital over to Vamed. This requires a number of rooms on the second floor to be changed. The client’s drivers are cost and time. Initially BWL priced the job at £90K for an architectural and M&E design role. The client currently doesn’t have a formal agreement in place with Vamed, so the real driver is to get the work done in order to seize a potential opportunity whilst spending as little cash as possible. This has led to a reduction in BWLs fee to £10K, which means BWL’s outputs are limited to a concept design which will be taken forward by the main contractor. I can understand the financial pressures the client is under, but it seems a little odd that the first interaction in a future strategic relationship is being done on a shoe string budget.

From an M&E perspective there are 2 engineers working on this project (1 electrical and 1 Mechanical). The limited budget means that this work needs to be turned around quickly, which is great for me as it’s another project under my belt for CPR.

What has my role been:

As the sole mechanical engineer working on the project I’ve been responsible for checking the implications of the changes of use on the mechanical system. This has entailed:

• Producing room data sheets for each area to define the environmental standards that need to be met (ventilation rates, temperature, acoustics, etc.)
• Using the data from the room datasheets to calculate loads for each area (cooling, heating, ventilation, domestic cold water, domestic hot water)
• Identify the best possible way to meet the new demands. As an example active chilled beams are utilised to provide comfort heating and cooling, where possible these have been retained, but where loads are too great or not close to the current distribution network other solutions have been provided.
• The impact of these solutions have then been confirmed: basically checking pressure drops in pipework and ductwork and making alterations where required.
• Engaging with my electrical and architectural colleagues to ensure that our designs are co-ordinate.
• This has then been pulled together into a scope of works, including mark-ups of existing schematics and schedules of new equipment so that the contractor can price the job and take the design forward.

All in all a good little project that has given me some solid B and D competencies. It’s probably worth noting that I found the calculations involved in conducting this work to be much simpler than those conduction for phase 1: phase 1 more than prepares you for the technical aspects of phase 3.