Examination of Witnesses (Questions 3520
- 3539)
3520. Can I ask then for you to talk in a bit
more detail about these scores? If a building scores 2, how does
your treatment of it thereafter vary or differ from if the building
had scored 3?
(Mr Berryman) I do not have the chart in front of me, but
the higher the score, the more intensive the modelling and the
analysis which is carried out to check the stability and adequacy
of the building for the settlement which is going underneath it.
Generally speaking, you start at the lowest level where there
is the lowest risk and you do an analysis of what we call the
greenfield settlement. If that is okay, you do not go any further,
unless there is some particular reason for doing so. If it is
not okay, you go to the next stage and do a more detailed analysis,
rising to the highest stage where you would do detailed finite
elements analysis using very sophisticated computer programmes
and very extensive analysis. The score just determines the amount
of work that is put in on that particular property.
3521. There are only three scores I think, it
is either 1, 2 or 3.
(Mr Berryman) You are talking about Phase 3 now, are you
not?
3522. Yes, that is all we have done so far.
(Mr Berryman) Well, in fact there are two phases before Phase
3, as you are aware. It is just that listed buildings go straight
to Phase 3.
3523. That is what we are talking about, listed
buildings. There seems to be three scores available, 1, 2 or 3,
and what we are not clear, we are putting a lot of effort into
asking to inspect them and certainly because we believe that will
lift their scores, as has been demonstrated, but we are not quite
sure what follows on from that, what have we achieved, so I wonder
whether you could explain what is the difference between 1, 2
and 3? What does it mean?
(Mr Berryman) It means that more detailed and more intrusive—
3524. No, specifically, if you score 3, how
does that affect the Promoter's response or how does that affect
the Promoter's dealings with that building thereafter? I cannot
get to the point of these scores.
(Mr Berryman) If you score 3, you do a very detailed analysis
of possible movements within the building, assess in detail what
the impacts might be on that building. We would still expect that
most of the buildings that scored 3 would still fall into the
negligible or very slight category of damage, but we would have
to make sure that our analysis was comprehensive, thorough and
included all the issues. If it was found that there were some
problems, then we may have to go to some strengthening or some
remedial work before the tunnelling came through but, as I think
you know, there is nothing on the route which falls into that
category.
3525. What happens if it scores 2?
(Mr Berryman) If it scores 2, we do an intermediate level
of analysis on the building to make sure that our original assumptions
are correct. We take into account the stiffness of the building
itself as well as the ground movements which are relevant in determining
how the building reacts. I think Professor Mair can fill you in
on that better tomorrow morning.
3526. When does this very detailed analysis
that you referred to in score 3 happen?
(Mr Berryman) It would happen in sufficient time before the
tunnel boring machines came through, to ensure that if any remedial
work or strengthening work was needed it could be done. I would
have thought twelve months or so before would be about the right
time.
3527. Twelve months. You mentioned that the
tunnels are going through between 2012 and 2014.
(Mr Berryman) Yes. The back end of 2012 at the earliest.
3528. So these final surveys, which you do—if
you have a score of 3 you qualify but you do not qualify if you
have only got a score of 2—they are done a year before the
tunnels come through. Is that a different procedure to the condition
surveys that you would do on all the buildings?
(Mr Berryman) Normally, we would try and do the condition
surveys at a reasonable period before the machines come through,
for the obvious reason that buildings can deteriorate in the period
between our inspection and the tunnel-boring coming through. So
we need to be about a year in advance of the machines coming through.
3529. MR WHEELER: So the condition surveys
get done pretty much the same time as your historic building surveys.
I am struggling to see the difference between how you treat one
category of building and another. It seems, essentially, they
are all going to be surveyed one day—rather too late.
3530. CHAIRMAN: I think we are at cross
purposes. I think that the surveys that will be done in advance
take two forms: will one of them not be a predictive engineering
survey about what is likely to be the effect on a particular building
of the tunnelling process, and the other sort of survey is what
the building is like now?
(Mr Berryman) That is correct.
3531. MR WHEELER: Yes, that is true.
3532. CHAIRMAN: Is that right?
3533. MR WHEELER: That is just what I
mean. The point is it seems as though both those surveys are going
to be done at exactly the same time. If this further survey for
the buildings that score 3 is done a year in advance of the tunnels
coming through, and what Mr Berryman is also saying is that the
condition surveys will be done at exactly the same time, what
I am wondering is how a building that scores 3 is treated any
differently to a building that scores 2.
(Mr Berryman) If a building has scored 3, further analysis
will be done on the actual tunnelling process and on the machine
that, by that time, we have already bought. The detailed analysis
of the movement of the building will be carried out at that stage,
and if any temporary propping or things of that sort (actually,
we do not anticipate anything like that will be necessary) we
would arrange for it to be done at that time, possibly the works
being done a few weeks before the tunnel-boring machines come
through.
3534. I understand that. The next question I
have concerns a map we saw right at the beginning of the piece
this morning, concerning the boreholes.[41]
Do we have that map available? Thank you. Can I ask what these
boreholes are investigating?
(Mr Berryman) They are investigating the soil
strata beneath the ground.
3535. Why do they so conclusively avoid where
the tunnels are going?
(Mr Berryman) The boreholes in this area were carried out
in the 1992 scheme. This is the only one we have done so far down
here. Crossrail is not a popular project in this area. We have
had great difficulty—
3536. CHAIRMAN: You do surprise me, Mr
Berryman!
3537. LORD YOUNG OF NORWOOD GREEN: "How
would you like a borehole in your garden?" does not go down
well!
(Mr Berryman) Absolutely. We have had great difficulty in
arranging for building owners to give us access. Of course, when
we have the powers which the Bill gives us we will be able to
do that much more conveniently.
3538. MR WHEELER: You should have been
around when Clancy Docwra have been digging up the whole area.
There are plenty of opportunities for boreholes.
(Mr Berryman) Regrettably, their boreholes are not deep enough
for our purposes.
3539. I see what you mean, because that is why
the boreholes carry on up north, is it not, because it is following
the original safeguarded route. Then you do not show any proposed
boreholes either following the actual route. I think we have spoken
about the variable ground conditions and what have you in this
area. It is alarming that the boreholes you are relying on are
actually not for the routes that you are pursuing. Are you not
going to be taking greater care to put a few boreholes down along
the route you are actually excavating?
(Mr Berryman) I do not know who has given you the idea that
the ground in this area is not consistent in its stratification.
Nothing could be further from the truth; this is quite a straightforward
area to map. The geology here is straightforward.
41 Crossrail Ref: P23, 10mm settlement contours and
boreholes-Spitalfields area (TOWHLB-XR5A-094) Back
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