278 



THK CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Sept. 



WESTMINSTER BRIDGE. 



R(port of the Select Committee appointed to consider the present state of 

 Westminster Bridge, dated August 5, 1816. 



The Committee having taken evidence on the subject of the present 

 state of Westminster Bridge, unanimously agreed to the following resolu- 

 tions and Report : — . u -r 



Resolutions. I. That the majority of the witnesses who have been ex- 

 amined on the point concur in the statement, that the foundations of W est- 

 minster Bridge having been originally vicious, the bridge can never De 

 permanently sound. 



II That the expense of completing the alterations and repairs now in 

 progress or coutemphition, according to contracts and designs ""fer the 

 superintendence of the bridge commissioners, will be very considerable, 

 amounting at the least to £70,000. 



III That this expenditure will still leave the bridge in a state requiring 

 constant attention in respect to repairs, and without any certainty ot per- 

 manent security; while it will likewise leave the -a'er-way far less 

 adequate to the requirement of the navigation, particularly when the con- 

 ^racVon of the stream by the embankment in front of the New Palace is 

 considered, than would be the case under a new bridge. 



IV That, irrespective of the approaches, the expense of a new stone 

 brid-e near the site of the present bridge, and retaining the present bridge 

 fo temporary use. would not exceed £360.000, according to the highest of 

 the estimates for that object which have been furnished to the committee, 

 either in 1844, or in the present year. 



V That the bridge estates would probably furnish a clear surplus of 

 at least £100,000. in aid of the funds for the erection of a "fw bridge 



vT That Parliament having by direct grants from the Exchequer (the 

 remaining expenditure having been provided by money raised in loiter.es 

 under Arts of Parliament) furnished a large part of the expense of erect- 

 in-, originally the present bridge, and having constituted the commission 

 Lder which the said bridge was erected and has since been administered 

 and haliic by sec. 20 of the 9 Geo. 11. c. 29, declared, that the said 

 bridge shaU be exlra-parochial, and by sec. 21, that it shall not be a county 

 bridge, maintainable as such bridges are by county rates, has recognized 

 and Lnctiourd the principle that this bridge, which .s thus by '«; J-I^j^ded 

 from other support shall be maintained, and when needful, repaiied, re- 

 stored, and rebuilt, at the expense of the State. 



VII That in these circumstances, a suffictent case has been made out 

 to iusti'fythis committee in recommending to the House, that the present 

 bri(b'e be pulled down, and that a new bridge be constructed ; and that a 

 bill be brou-ht into Parliament next session to transfer to the Commission, 

 ers of Her Majesty's Woods, &c., the estates and property of the bridge 

 commissioners/due consideration being had to the claims of the oSicers of 

 the bridge estates, if their services should be discontinued. 



rteoort —The practical question which the committee had to decide, in 

 relation to Westminster bri.lge, was, whether, under all the circumstances 

 of the case, it were or were not desirable to endeavour to maintain the 

 existing fabric of the bridge, or, on the other hand, to pull it down at once, 

 and to substiiute an entirely new bridge. . r j 



n e result of the inquiiy instituted in the session of 1844, and referred 

 to this committee, proved unquestionably, that, without relerence to money 

 (i. e. assuming that the pecuniary means were forthcoming) "^^y ^o"^"'- 

 eration of the convenience of the passage under and over ^'e bridge and 

 even of economy when the expense of the maintenance of the existing 

 structure is regarded, combined to recommend the removal of the old 

 bridae, and the erection of a new bridge. ,. , ^ „, 



It was Slated in substance by several witnesses examined in that year, 

 that the foundations of Westminster bridge were originally defective , and 

 therefore that the superstructure could never be made as eflect.vely secuie 

 as it the whole were now rebniU on an improved plan. 



Evn irrespective of the particular vice of the foundations, the charac er 



of the soil on which the bridge is built was suthcieutly illustrated by the 



late Mi: Telford, in the following passage describing one of h.sown opera- 



tiuns on the site : " I then proceeded to ascertain the nature of the matter 



of wluch lie bed is composed, and on which the piers rest; and I found 



"hatan iron rod was easily pressed by hand through sand and gmvel, to 



the depth of six and a half feet below the surface of the bot om of the 



r ver, or three and a halffeet below the bottom of the platform ; how much 



lower a longer rod might have penetrated I had not an opportunity of try- 



„"•■ \nd as to the foundations, James Walker, Esq. C.E., who was at 



the time, and still is, the professional adviser of the bridge commissioners, 



stated 11 1844, ' All the defects of the bridge have arisen from the imper- 



ect foundation of the piers." In his original report '» 'h'L'o™'"'^ '""^/i 



of Westminster bridge, seven years before, namely, 2bth February 1837, 



Mr Walker alter having stated "that for every useful and ornamental 



purpos: a new bridge would be preferable, if the funds will justify the 



expense," proceeded to slate the facts and reasons vvhich led to =»"•'' con- 



elusion nLely, "that the |.iers of Westminster b"dge w^'^e built in 



caissons, wuhout bearing piles under them; that the bed o the river for 



a considerable depth under the caissous. is loose gravel ; and that the 



eilect of the removal of the piers and dams of London Bridge is to increase 



tiie velocity ot the ebbing current, and to deepen the channel between the 



piers, and thus to endanger the foundations." After the experience of 

 Dine more years, Mr. Walker, reviewing the whole case and being re- 

 quested to state his opinion as to '^/perfect stability of the existing fabric 

 o( the bridge" says, on the 19th of May, 1846, " After that bridge h.s 

 sunk and twisted about m the way it has done, from the commencement of 

 its building to the present time, I have seen enough of it not to risk any- 

 thin.. like a professional opinion upon it,' , e. its perfect stability. . .. I 

 feel with reference to Westminster bridge, that it is like a patient whose 

 constitution I did not make, which has been in the hands of doctors from 

 the day it was built to the present time." Mr. Walker added, indeed, on 

 the same day, " 1 do not think that there is any reasonable expectation of 

 anything like a sudden failure of the bridge that would cause public dan- 

 ger; but when it is considered what an immense stake there is in the case 

 of any accident happening to the bridge, to be set against he '^king of the 

 thing Ldly in hand, and making a complete job of 't /t once to „ e an 

 expression common with us, I must say, as I have said from the begin- 

 ning hat it is Lthing but a deference to the Lords of th. Treasury which 

 won d in my mind make it politic at all to expend a great deal of money 

 upon the repair of the old bridge." Mr. W fubitt, C L , stated in 18i7 

 in his report, "It .Iso appears from the history of Ihi. bridge that the 

 oundat!ons,'as at present existing, were designed and - -1» ^^ ^^ "-^ 

 smaller piers, with a light wooden superstructure for a bridge; which plan 

 was af envards changed to that for the present stone bridge, and carried 

 into effect upon the original foundations, by casing or ^■'■"S out '^.e pie^», 

 and surmounting them with heavy stone arches. Lnder these circnm- 

 stances, it is not surprising, as was stated in a contemporary work, which 

 describe the erection of the bridge,-that, " before the bridge vvas evea 

 finished viz in 1747, the third pier from the centre, viz. the hfth from the 

 Westminster shore, began to sink ; so that the two arches which rested on 

 t d pa;"d from th'eir circular figure, and some of their ?"-?=';'»-/ 

 fell into the water." (Gephyralogia, 1751, p. 111). The remedy applied 

 n he first instance, according to that authority was, to lay such a weig t 

 on the pier as to sink it gradually to the level where ■'"?'>' fi"d^f 

 Accordingly, a weight " amounting to 12,000 tons" was laid on the sink- 

 fng pie, Ipparently to sink it lower; and it "continued sinking several- 

 months Lfter the weight was laid on." Three whole years was the use of 

 this noble structure retarded by this accident, pp. 111-13. it '^ 'r"e. 

 however, as the late Mr. Telford observed, in a memorable repo t wh. h 

 he addressed to the commissioners of Westminster bridge, on ihelilU 

 Mav 1823 that "the dangerous instability of the piers of AV estmins ter 

 bridge seems to have passed into oblivion." It is true, ^l^^'-'^f'' •/*''" 

 Walker observed in his evidence, that, "in the '='>''''<' ''..ZlLo'dol 

 fabric had come to a stale of repose, comparatively, until oU London 

 br dge was removed, the eilect of which was to ^^?''l''Z"-Z\'''ZJerl 

 tidalcurrent. This deepened the ground under the bridge and the pier, 

 being thus deprived partly of lateral support, and some of he fine and 

 also getting from under the caisson bottoms, they began to be restless 



''^Tbe cause of the original failure in 1747 was the omission of driving 

 pills under the piers ; but the miserable economy "f^Yt 'to'be'th—u 

 sand pounds, for which Mr. King (whose name ought to be there"pou 

 preserved in honour) oflVred to execute the work, P^.^''^^'^,' f,rf(j 

 was " not one part in GO or 70 of the whole expense of 'h^ b"dge (Ge 

 vhiiralo'rm pp 96, 97). Hence, the first faduie ; and hence all the sub- 

 ^e^uent°wea'kl;ess;s of the struc'ture, and the enormous expense of make- 



shift repairs. lu n „- 



When engineers like the late Mr. Telford and the present Mr. Walker 

 suggest a remedy for an evil, occuring in the line of their own professiou 

 Tnf fn n'a te" d'aily under their eyes, those who have not 'l-e advantage of 

 their science and experience ought to be slow '" P™""""^?, ^° °P'^^~d 

 favourable a priori to any suggestion so made. Mr Td o^d ■^^!';7"\',"„^?J 

 that, as piles had not been originally driven under the PerSP'le should 

 be driven round the piers, using the d.ving-bell for P ac.ng hem and cut 

 ting them. A number was done in this way ; but even those tha were 

 done did not seem quite at rest; and the commissioners, f^rom the expen^se, 

 uncertainty, and delay with which the operation "''.^/"^"'^f,'^' ^™: 

 before I was called in" («aid Mr. Walker in his evidence) o have n^^ 

 solved, for a time at least, not to enclose any >>'ore of the p eis -n the way 

 I have described." Then came the system of coffer-damm.ng^ M> de 

 cided opinion is that cotlei-damming is the best plan : and that P'^n « -'S 

 thereupon adopted; but while "r. Walker discontinued Mr. lelfords 

 useof the diving-bell, and did not concur in Mr. Cubuis pan of paving 

 "hebedof .l.erfver,Mr.Cubitt, on the other '-"<»,. eq-'f,,-"~f. 

 the use of colierdams in the case of Westminster bridge ; s'*' "S f '=""" 

 ly " That in the case of Westminster bridge, ''^e'.r.g.ual construction and 

 p^resent state of the foundations are such as wdl ^''[^t . r.^ei 

 dam plan being carried in.o effect with safety to the bridge, " « je 

 go"nded certainty of asuccessful result" between these tvvo d'scordiu t 

 Lthorities, the commissioners made their election, a»d »?;,'? edMy;;,. 

 ker's plan of cofler damming, and in the course of the following year 

 tered into contracts for completing it. _ 



It is due, however, to both gentlemen to state that, even m 1837 mey 

 each recommended a new bridge, if the pecuniary means ««"'^ ^f,^ ^J^J 

 in preference to any attempt to repair the old structure, f "^"j;! I'^^'j';^. 

 " l^iat there is no doubt but a new bridge would cure all the ev Is com 

 plained of." And Mr. Walker enumerated those consideration which 

 "would probably turn the balance in lavour of the new bridge. At a 



