Professor Soga and the Crossrail Link
What is it with this instrumentation thing? I was in Pretoria last week listening to Professor Kenichi Soga talk about geotechnical monitoring. Although now based at the University of California, Berkeley, he was previously based at Cambridge University for 22 years. Californian sunshine apparently was the draw, certainly not the earthquakes. Anyway, I was totally impressed by the way in which they approached the monitoring for the new Crossrail structures in London. This was not a ‘nice to have’ component of the project, but formed an integral part of the design and management process. New tunnels were being advanced in close proximity to existing infrastructure and they needed to be sure that the settlements did not exceed certain thresholds.
He in a way echoed the sentiments expressed by John Dunnicliff over 30 years ago. Dunnicliff back then said “the design of geotechnical construction will be based on judgement in selecting the most probable values within the ranges of possible values for engineering properties. As construction progresses and geotechnical conditions are observed or behaviour monitored, the design judgements can be evaluated and, if necessary updated. Thus engineering observations during geotechnical construction are often an integral part of the design process, and geotechnical instrumentation is a tool to assist with these observations”.
And this is exactly what they did on the Crossrail project, but they took it much further. The Cambridge team examined the problem in association with the consultants on the project, decided on what instrumentation was required, innovated new technologies, carried out the installation of both old technologies and new systems, were involved in the data acquisition and interpretation, corroborated results against the older, tried-and-tested methods, and were central to the decision making process during critical periods when new tunnels were advanced in close proximity to existing infrastructure. The results speak for themselves.
Do I open a pie shop?
Compare this approach to the way we do things here. The Design Engineer designs for instance a dam. The QS then works out the quantities and the project goes to tender. The bidding construction companies send out emails to the various service providers and suppliers, with extracts of the tender document supposedly pertaining to the relevant portion of the work. We receive these emails and ask ourselves a number of questions which generally are as follows:
- Who else is bidding on the project and can we give them a price?
- Who is the design engineer?
- Are there additional drawings and a detailed specification for the instrumentation component of the project?
- Why does everyone leave everything to the last minute!?
- Why am I doing this kind of work – would it not be better to open a pie shop?
Where are those damned drawings?!
The problem of course is that the Design Engineer has not provided a detailed design of the instrumentation system architecture and the bidding contractor has not provided us with the entire contract document and drawings. We need this information NOW as the tender closes next week and we need to know distances of cable runs, the location of galleries, where the control room to house the data loggers is to be located, and decide if we are going to have a distributed architecture or house all the multiplexers in the control room. So where are those damned drawings? Getting them is like squeezing blood out of a stone. Then long discussions take place with our counterparts in Italy and eventually we come up with a design and pricing. All well and good.
Prices are submitted along with proposals, BEE certificates, tax clearance certificates, staff CV’s etc etc. Read weeks of work. We are not sure who else is bidding for the instrumentation, but we can be assured that the contractor is looking for the lowest price on the instruments and on the installation.
A race for the bottom
Which brings me now to some wise words written by Ralph B Peck, in the forward to Geotechnical Instrumentation For Monitoring Field Performance. “The installer must also want desperately to do the job well and must often work under difficult and unpleasant conditions, trying to do precision work while surrounded by workers whose teamwork or operation of equipment is being interrupted or working the graveyard shift in an attempt to reduce such interruptions, Dedication of this sort is the price of success, and it is rarely found at the price tendered by the lowest bidder. Moreover, the installer can hardly be motivated to be dedicated to the task of installing instruments of inferior quality that are likely to fail prematurely or to produce questionable data”.
So we all find ourselves in a race for the bottom so to speak – subcontractor, contractor and engineer. Cheap on all accounts and the owner left with a poorly performing system at the end of the day. We recently had an experience on a dam project we have been involved in – the contractor didn’t want to buy our instruments, preferring to buy cheaply made ones from distant lands. The Resident Engineer insisted that they buy from us, which they did, but then they opted to do the installation themselves. However they weren’t averse to calling us to solve their problems in spite of us receiving limited remuneration for our troubles. I did eventually wrote to them distancing ourselves from the project as our reputation was being damaged. Everyone lost out in the end – the Engineer, the Contractor, the Instrumentation Contractor and the Owner. Reputations were damaged, data were anomalous, repairs are ongoing and at times tempers were running very high.
So how can we resolve these issues? Crossrail could be our model. At the very least the Instrumentation Contractor could be consulted by the Engineer at the outset to assist with the design of the system architecture. Better still, the system could be designed, installed and monitored by a dedicated team working under or in close association with the Engineers as per the Crossrail example. If this isn’t possible, then the instrumentation component of the work should at least be set up as a separate contract managed by the Owner or Engineer, rather than put into the hands of the main contractor who will only be governed by price.
And what a beautiful thing that would be.