280 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Sept. 



eestionof sheet-piliDg, " I believe I did not sufficiently explain that by 

 driving piles through loose sand and gravel, that the matter is always dis- 

 turbed, and, during the operation of driving, liable to be washed away, 

 and of course produce more risk to the piers than if left undisturbed. 

 And iMr. \V. Cubitt being asked, as the contractor engaged on the ^^■urk, 

 " Can you stale to the committee whether it be or be not the fact, that 

 every pier, as has been alleged, with only one exception, sank, more or 

 less, after the sheet-piles round it to secure the bottom of the caissons from 

 being underwashed by the general deepening of the river, were driven ?'' 

 Iklr.W. Cubitt replies, "they have not all sunk;" and being thereupon 

 reminded " The question implies that one was an exception; do you wish 

 the committee to understand, that all the piers, with one exception, have 

 sunk more or less since the piles were driven ?" Mr. W. Cubitt answers, 

 " I am not prepared to state positively that they may not all of tbem 

 have sunk a Utile. I am not quite sure but that they may have sunk an 

 inch or half an inch, or some very slight thing ; but one of them sank nine 

 inches, and another sank two inches." And as to the future, Mr. W. 

 Cubitt bad already stated his previously formed opinion, that the bridge 

 was not in any part of it in a state of perfect steadiness ; that it might 

 always be liable to subside a little, from the defect of the foundation." 



The result of the whole question connected with this species of repair 

 is slated by Mr. Walker in answer the question, " Do you think that the 

 tiridge will now be brought to a state of as perfect security and stability 

 as a new bridge, if you were called upon to construct it?"—" Certainly 

 not" And in answer to the next question, "Do you think that by any 

 resources of your professional art, this bridge can be brought into a state 

 of perfect stability and security as compared with a new bridge?" Mr. 

 Walker replies, " Without hesitation, I say, there is no art that can make 

 the piers of this bridge so secure as I could have made a new one." It is 

 right, however to add, that Mr. Walker staled, in his examination this 

 session, " Ihat the measures which had been adopted had been completely 

 successful in preventing any further movement in six of the piers: * ^ * 

 there has been no movement since" (i. e. since the 7th of May, 1845,) "in 

 any of the piers, except the two I have already referred to." Neverthe- 

 less, in answer to the question, " Are you, or are you not of opinion, that 

 with a due regard to the public convenience, and to avoid danger, arrange- 

 ments should be made, without loss of time, for building a new bridge?"— 

 INI r. Walker's answer is distinct : " Certainly, without reference to money, 

 I say ' Yes.' " 



As to the mere durability of the bridge, by which the committee under- 

 stand ihe perfeclness of the masonry both in the arches and in the piers, 

 excluding always the question already discussed as to the stability of the 

 foundation, there appears no reason to doubt the accuracy of Mr. Walker's 

 opinion : "There is no part of the work which will not last for ages;' 

 but a qualification to this opinion must here be given on Ihe authority of 

 Mr Walker himself, who, in 1837, stated as follows:— " From the piers 

 being intended originally to carry a wooden bridge, and being cased round 

 when a stone bridge was resolved to be substituted, and from the very had 

 quality of the masonry, the superstructure never can be made a very secure 

 and solid work ," and even admitting Ihe superior accuracy of his later 

 opinion, when, during the interval, be had had fuller opportunites of ex- 

 amination in relation to the durability of the superstructure of the bridge, 

 it is obvious that this admission does not at all establish the expediency of 

 maintaining the present bridge so long as Ihe first and main question, as 

 to Ihe sufficiency and stabiliiy of the foundations on which the structure 

 rests, remains in a stale so unsatisfactory as at present. 



It was not contended in 1844 that the bridge was then in a " perilous' 

 state- Mr. Walker expressly repudiated the word; and, even before the 

 new system of repairs, he had sUted, " that the bridge is not in immediate 

 danger;" and W. Cubitt, Esq., the civil engineer (and not the gentleman 

 of the same name, who is Ihe contractor for the bridge), being asked, in 

 reference to the state of the bridge when the repairs should be completed, 

 " Your conclusion is, that the bridge will be an insecure bridge ?" replied, 

 " A very doubtful one." " You will not say it will be an insecure bridge? ' 

 —"No" He had been previously asked, " Do you regard it possible, 

 with any talent and any expenditure of money, to make Ihe foundations of 

 Westminster bridge as secure, under existing circumstances, as the founda- 

 tions of a new bridge could be?" replies, " Certainly not." Mr. Cubitt, 

 C E further states, that " from what I have seen, 1 would rather build a 

 new bridge than spend more money upon this, seeing it has done exactly 

 what 1 cxpecied it would do when I made my report in 1837. My opinion 

 is that it IS best not to go on spending a great sum of money to repair and 

 w'iden and beauiify this bridge, which never can be good, either in its road- 

 way or in its foundations." Therefore, under all the circumstanres, the 

 hridge having proved to be too heavy for the nature of the clay it stands 

 upon It being very difficult to protect it without piling and paving, 1 say, 

 asanengineer, that the best thing is to dispense with all further repairs, 

 and make a new bridge. I said so before, and Mr. \\ alker said so also, 

 and I am confirmed in that by what has subsequently taken place." And 

 when asked in the next question, " You consider the only question to be 

 one of finance ? ' he replies, " Certainly ; the bridge is a mass of rubbish. 

 The piers and the masses of masonry and rubble were lirst built for a 

 wooden bridge, which was afterwards converted into a stone bridge, and 

 heavy arches were put upon ihat which was not more than strong enough 

 f..r a wooden bridge." * * The small piers were then cased round to 

 make ihem larger ; and springings were made for stone arches, and a very 

 biavy bridge was put on those foundations," 



Though Westminster bridge so constructed, — without piles and on the 

 imperfectly-levelled natural bed of the river, — did actually fail during its 

 construclion, yet, " after it was constructed, and the arches which had 

 failed were rebuilt, it stood for some 60 or 70 years unmoved." • " On 

 the removal of the dam caused by old London bridge, "a wider passage 

 was opened to the Thames, and the foundations of the arches underneath 

 Westminster bridge began to weitr away ; so much so, that they caused a 

 great apprehension of the bridge falling ; and from time to time they were 

 repaired by the diving-bell, and various other modes. Mr. Telford was 

 called on, and advised stones being thrown in ; and he advised also to pave 

 underneath the arches between the piers, so Ihat the bottom might not be 

 washed away. After his death, the commissioners did me the honour to 

 call upon me to advise them. I considered the thing, and felt quite aware 

 that disturbing the bottom would not be a good thing ; but that if we could 

 continue the bottom exactly as it always was, the bridge would stand the 

 same as it had done ; that there would be nothing to prevent it ; and to do 

 that, I propose to pave with large stones, two feet tliick ;" * • • •• to 

 pave a perfectly fiat floor down as low as the frames which form the foan- 

 dations, and have been carried into the soil." • • • " J proposed, 

 paving under the whole of the bridge, and 50 feet parallel along it, above 

 and below, so as to make a perfect stone pavement ; with such pavement 

 the bottom never could have washed away ; and without washing away, 

 the piers would not have fallen down." 



A suggestion made by such an authority as Mr. Cubitt, C. E., is of 

 course entitled to Just attention ; but your committee, after bestowing that 

 attention upon it, feel bound to state two objections to it, which, in their 

 judgment, are insuperable. They relate to the effect of the plan upon the 

 navigation, and to its cost. The one may be conveyed in the admission of 

 Mr. Cubitt himself — " The only disadvantage (if disadvantage it can be 

 called) of this plan is, that it limits the depth of the navigation under the 

 bridge to the level of the stone paving; but as this would be greater, by 

 about three feet, than originally existed, and till after the removal of the 

 old London bridge, I imagine that no complaint could arise on that head." 

 • • The answer to this observation is, that those concerned with 

 the state and probable condition of Westminster bridge have to deal with 

 Ihe river, and its actual depth in 1846, and not with its depth in 1823; and 

 must not forget that if the river has deepened under the arches, say six 

 feet, the proposed plan of raising a pavement of something like three feet, 

 would take away a depth of three feet from the actual navigation. The 

 second objection is, that irrespective of all repairs to the bridge; and leav- 

 ing that bridge as it is, the probable cost of the paving would, in Mr. Cu- 

 bitt's own opinion, be about £120,000. It is not necessary, therefore, to 

 pursue this subject. 



Another remedy was proposed by another gentleman, Wm. Hosking, 

 Esq., architect and engineer, and professor of the principles and practice 

 of architecture in King's College, London. While he differed from other 

 witnesses on some important points, and specially in his belief that " the 

 present foundations might be rendered sufiicieuily secure to be entrusted 

 with a new superstructure, especially if the superstructure was not an 

 unnecessarily heavy one," he concurred with almost all in the opinion that 

 the present bridge cannot be made " permanently available," to use his own 

 words, " without the bar or weir I have spoken of, which I consider to be 

 an absolute essential to the security of the existing foundations." Now, 

 inasmuch as the bar or weir in question is, in the judgment of the same 

 witness, a necessary precaution " at the other bridges" also, as otherwise 

 "all the other bridges will be undermined as well as Westminster bridge," 

 it ii clear that his remedy must be viewed in relation to the whole of the 

 river as it flows through the metropolis ; and irrespective of the objections 

 to which the plan, if ever adopted in any one breadth of the river, would 

 be liable as an obstruction to the navigation at that part (which, even Ihe 

 witness admits, " it certainly would not improve,"), and so on, wherever 

 adopted, the ultimate expense of making successive weirs above each 

 bridge would be obviously immense ; and the committee — to confine them- 

 selves to the consideration of this project in relation to Westminster bridge 

 alone, the immediate subject referred to them — cannot recommend any 

 further attention to it. 



However wonderful as a structure Westminster bridge was regarded at 

 the time of its erection, and there is reason to believe that at that time it 

 was the longest stone bridge which covered water all Ihe year round, not 

 in England only but in Europe, Mr. Hosking expresses an opinion, in 

 which your committee fully concur," that a bridge, in every respect better, 

 would be produced at the present time by almost any man of moderate 

 ability, who is conversant with the subject." 



On the general subject, both of the present state of the bridge and of 

 the expediency of subsistuting a new one, other professional gentlemen, of 

 the first character for skill and for experience, give evidence to the same 

 effect. 



Mr. Rendel states, " I should be very indisposed to risk any professional 

 reputation upon giving to the present structure that permanent character 

 which is adverted to." — "The foundations are wholly different from the 

 foundations of any other bridges across the Thames." — "I do not believe 

 that any talent or any skill, or any application of that skill, could, at a 

 cost which 1 should call justifiable, give to the preseut bridge that security 

 which its importance demands." 



Mr. George Kennie states, " I should decidedly condemn the old one 

 (the bridge), and recommend the expediency of its being taken down, re- 

 garding It us an engineering question entirely," — "Setting aside that (i.e. 



