ST. PAUL'S CATHEDRAL

Otago Daily Times, Issue 13996, 31 August 1907, Page 9

ST. PAUL'S CATHEDRAL

NO IMMEDIATE DANGER-,

PERIODICAL EXAMINATION NECES-

SARY,

Press Association—By Telegraph—CcpyrigLl LONDON, August 30.

_ (Received August 30, at 9.27~p.m.) A committee of architects reports tlk St. Paul's Cathedral is in no immediate danger, but that the fabric and! subsoil should be periodically examined.

The repeated warnings given regarding file condition of St Paul's Cathedral liavo brought forward several interesting theories respecting tho cause of the sinking of the south-western tower and other portions of the cathedral on the southern side. At first it was generally supposed that the sinking was duo to tho draining of the gravel subsoil by the construction of adjacent buildings arid suoli works as the underground railway. In llio belief that this was tho cause, tho London County Council this year decidcd to adopt another route for a sewer which it proposed to construct at a distance of 45ft from tho south-west tower. A "tube" railway project has nlso been abandoned for tiro, same reason. Mr f*. 0. Churchward, M.1.0.E., an engineer with groat practical knowledge of foundations, , after careful study of the matter, 'has propounded an entirely View theory and suggests a new remedy. Mr Churchward state! that tho foundations of St. Pauls' wore in an unstable and unsatisfactory condition, and thW lias recently been placed beyond all doubt by the. declaration of three of the most eminent architects of the day that the structure is in a. "'sensitive condition." and thoir indication of "(lie three portions of tho buildup that have from time to time showaitho most sisnifiocnt points of weaknoss." With tho abandonment, of I,he construction of a sewer contiguous to the edifice the matter appeare to have -been laid to rest, but the structure continues in a "sensitive condition." If a careful study is made of the peculiar topographical position of St. Paul's Cathedral in relation to tho Thames, only 300 yards distant, with tho bed of its channel 76ft below the brow of tho hill on which tho south face of the building is situated, it will bs seen how the river narrows and forms an angle at Paul Stairs, and how the bank is - washed by the swift current of tho ebb tide, enhanced by the broad sweep of tho Thames Embankment ending at Bkcldriars bridge. Established fads taken in conjunction with the above condireveal tho truo cauftc of tho "sensitive state of the structure, which appears to have entirely escaped observation. Here t ro the facts; they cannot be gainsaid. rho south-west (clock) tower and tho south-west and south-east piers of tho support ot the 'dome are' tho throe portions of tho building that- have from time to timo shown* tho most significant points of weakness, Messrs John Britton, FiS.A., and Augustm Pugin, architect, in their work Illustrations of Public Buildings of Ijoiidon, 1825, thus describe their examination of tho foundations ; " The foundations of tho structure stand upon hard pot earth, the stratum of which on the north side was discovered to be 6ft thick and upwards, but on the eOuth side not moro than 4ft; immediately under it lies sand of eowidorable depth." They give an excellent comparatiyo plan of 'the ancient and present cathedrals, and add: "As tho oid cathedral had rested securely on pot earth, the architect concluded with great good sense that his building might bo trusted without tear to tho same bottom that bad borne tho old one. Tho result lir? proved that lie was not mistaken."

Prom the above, seismic disturbances, as a cause, may be dismissed. The structure was intact in 1825, and earthquakes wero more frequent and equally as violent in • ibuilding had stood tlmn m tho 82 years that . have elapsed 6ince. tho comparative plan reveals tho fact that the foundations of the three, portions of tho nuilding that havo -shown tho most fV-jrnifi-cant weakness-are the only portions of Sir Christopher Wren's St. Paul's that are not built over or contiriguous to tho foundations of th-3 ancient cathedral and cloisters 0 bv centuries of ago, lho final fact is that modern requirements of navigation have necessitated tho removal by dredging of tho natural impervious crust or original bed 6f the river which obtained at the timo the cathedral ,1™ S'" Kl PrabaMy. to a date later than 18i°. Dredging has gone on continum since, until at the presont time a deep hole extends in front of tho cathedral in tno river below it, reaching from Paul Stain to Queenhitlic Dock, which in no tb 16 ? an t 32ft dec 'P> and Toadies the great depth of 36ft below Trinity high

Here, then tho true causo of tile suhji--Ims?y v? l0^1 ' 1 !of - Thc santl .nntl f "dp .or apex along tho whole [S 00 !. ° 1 ? atho d"d under the pofc Vr thM \ whrch ,! 3 ,more than floutl, «^ 1 ' / a ? d ,?/ h f >l l arc f0 the aoutli-Hest (clock) tower and the southwest and south-east piers of the support of tbe dome, which from timo to time have shown the most significant points of weakMrfi, cw 8 i? - formed hy tho Pot earth stiatum increasing i n depth to tho hen Artl, '."ol'lins from tho face of tho building to tho Thames an the

With the sa,nd skaliim. following the stirace contour to , deptJi of aLt 40ft, from the apex down to tho river, and tho natural impervious bod of thc river gone, millions of tons of watov ponetrate under the foundations of the cathedral twice daily with the rising tujes, and as often pass out wiili the receding tides, sucking out tho sand from between tho flints and pebbles, or, settling it, oauso it to silt up in the channel, which must be kept open for navigation at low wator; and so the process goes on, accoleratod by veins of quick or running sand, if they exist, as found on the south bank of tho river, or uy higher tide* and deeper dredging. Tho sand stratum thus cut into refuses to lie at any other than its natural slope, and sand behind it runs down to malro good tlio slope removed, and thus tho highest point of. the stratum settles; and the 4ft of pot-earth stratum on which tho mac-sive structure stands gives way with the vacuum earned |>y ti lfl running away of the sands of time" from beneath it, and thus creates the "sensitive condition" of the structure.

As regards remedial measures, a river wall 410 yds long and 50ft in depth, well founded in the solid London clay stratum, between ilie abutments of Blackfria-ts and ooiithwai'li bridges, carried out in lino and level of the half-tido barge bertha in front of the warehouses (the barro berths to nave their lower beds lined with a very t 11 °f. clay middle), as <i retaining wall, would effectually stop all leakage of 'he sand stratum. Tha.river would not bo reduced an inch in breadth, and dredging operations could bn carried on without detriment to any of (he buildings on the south bank-, so protected. If a 4in-diometer pipe were sunk on the north side ol the cathedral 52ft below the surface, with the bottom end well perforated for 12ft. and fitted with a rod and float, it. would indicate high water in the 1 names below. The cost 'would bo small, while the result would prove boyond doubt the true cause of the "sensitive condition" of St. Paul's Cathedral.