Select Committee on the Crossrail Bill Minutes of Evidence


Examination of Witnesses (Questions 12300 - 12319)

  12300. I know from personal experience: I have a wall and I have had it raised, and there was a point beyond which we could not go but the foundations were sufficiently strong, actually, to put numerous layers on top of the existing wall.

   (Mr Berryman) If a masonry structure is taking a purely vertical load, the weight of the wall, you can built it very, very high indeed, but it will soon blow over, I am afraid, my Lord.

  12301. I am in Brighton with very strong winds indeed and it has not blown over so far, and I was assured it would not blow over.

   (Mr Berryman) How tall is it, my Lord?

  12302. It is under the statutory height of two metres.

   (Mr Berryman) My Lord, this wall is already 2.5 metres tall.

  12303. LORD BROOKE OF ALVERTHORPE: Point made.

  12304. MS LIEVEN: I think, perhaps, we will leave that wall where it is. Mr Berryman, I think those are all the issues I need to cover with you. Thank you very much.

  12305. CHAIRMAN: Lady Bright, do you want to ask any questions?

  12306. LADY BRIGHT: I would like to ask a few questions, please.

Cross-examined by LADY BRIGHT

  12307. LADY BRIGHT: Mr Berryman, if you were needing to build a railway wall in this location—if you were doing that now, in other words—and you suggested building it another metre-and-a-half or a couple of metres higher, how differently would you specify the building of it?

   (Mr Berryman) In other words that would take it from 2.5 metres high, which is the approximate height of the wall now, to four metres, we would either do it in reinforced concrete, which obviously is able to take tensile stresses as well as compressive, or we would put—probably more likely—concrete columns at intervals along it, and then have the brick panels between the concrete columns. It would be a different design altogether.

  12308. So you do not think it is adaptable.

   (Mr Berryman) The present design, which is purely brick, unfortunately, is not adaptable in that way.

  12309. Can you tell us what assumptions you have made about the weight of the four-metre barrier you have been describing?

   (Mr Berryman) The weight of the barrier is actually immaterial, Lady Bright, because the loading of it is easily able to be sustained by the brickwork—that is absolutely no problem at all, as I have just explained to their Lordships.

  12310. It is purely the wind-loading we are talking about.

   (Mr Berryman) It is the wind-loading which is the issue.

  12311. That wind-loading issue applies whatever the height of the barrier?

   (Mr Berryman) The wind-loading goes up, as I said earlier, as the square of the height. So if you double the height you increase the wind-loading four fold.

  12312. I think you would accept that there would be some argument about the acceptability of the wind-loading on a lower barrier. We are only talking about a metre-and-a-half here.

   (Mr Berryman) No, there would be no doubt about that, Lady Bright; it is a matter of simple mathematics.

  12313. One-and-a-half metres would reduce the sound by 3 decibels—halve it.

   (Mr Berryman) I could not comment on that, Lady Bright. What I can tell you is that one-and-a-half metres would make the wall fall over unless it was given substantial foundations of some sort or another.

  12314. The principal objection to that is cost.

   (Mr Berryman) There are several objections. There are objections of cost, there are objections on the Conservation Area grounds—I cannot imagine that Westminster City Council would be relaxed about such an impact on the Conservation Area.

  12315. You cannot speak for the local authority on this.

   (Mr Berryman) I cannot.

  12316. LORD JAMES OF BLACKHEATH: A question please, Mr Berryman. As compared to the wall going up, what are the implications both in terms of its stability and its sound resistance if it gets thicker?

   (Mr Berryman) Making the wall thicker, obviously, would make it more able to sustain lateral loads, my Lord, but the point there would be that you would have to find a way of bonding into the existing wall, which is not particularly easy, and you would have—

  12317. Could you not have the facings?

   (Mr Berryman) You would have to found the additional thickness on something; you could not just stick it on the front.

  12318. You cannot just stick a facing on with Superglue?

   (Mr Berryman) I think the answer to that question is almost certainly no. People have been experimenting—

  12319. I am intrigued by the qualification "almost".

   (Mr Berryman) Well, the reason I say "almost certainly" is that I know that one or two academic institutions have been doing experiments with sticking carbon reinforced—



 
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