4. “On Earthquakes and Architecture,” by T. Turnbull, F.R.I.B.A., M.I.G.A., and A.C.A.
In opening, Mr. Turnbull explained that as Mr. Maskell had, in his paper on the same subject read at a previous meeting, with only one exception, criticized buildings of which he had been the architect, he felt
it was his bounden duty to those who had employed him to vindicate the faith he had in the stability of brick buildings, and to show as far as he could those gentlemen, as well as others, that their confidence in the foundations of our city was not misplaced; and also to prove that modern science had in architecture acquired sufficient knowledge of construction to be able to erect buildings capable of withstanding earthquakes even of a severer nature than they were ever likely to experience here. The subject was an important one, as, without sufficient confidence in the lasting stability of the buildings, those who made our cities would never attempt to erect any of a permanent character. Thus the progress of architecture would be checked, and the best index of our civilisation impaired. From this point of view the subject was not only an important but an interesting one. As Mr. Maskell had quoted Professor Milne, of Japan, as probably the best living authority, which from the tenor of his paper he (Mr. Maskell) evidently believed, Mr. Turnbull said he would refer to portions of the Professor's work on the effect of earthquakes on buildings, for the purpose of showing that he was not as infallible as Mr. Maskell would have them believe. When he (Mr. Turnbull) had read several chapters in that book he had come to the conclusion that the Professor, with all his talent, knew little or nothing of architectural construction, as he used words and phrases that were unknown in practice; and nowhere did he give any specific information as to the mode of construction, or the qualities of the material used in the buildings injured, but contented himself with stating whether of brick or stone, and often not so much. He then quoted the Professor's works at some length, and endeavoured to show that he was not so much an authority as Mr. Maskell would have them believe he was. He referred especially to one statement made by the Professor, “that a civil engineer, writing about the New Zealand earthquake of 1855, when all the brick buildings in Wellington were overthrown, says that it was most violent on the sides of the hill, and least so in the centre of the plains.” The Professor had quoted this from the report of the British Association of 1858. Now, they all knew this sweeping assertion to be wide of the truth; and they might well ask, What about the rest of the Professor's quotations? Seeing this assertion had been made from such a source, and repeated in such a book as the Professor's, he had made inquiries concerning the earthquakes of much-abused Wellington; and he mentioned Messrs. T. McKenzie and J. Plimmer in particular. There had only been three earthquakes of any consequence since 1840—namely, in 1840, 1848, and 1855. The earthquake of 1848 was of a much more severe character than the one in 1840, and many of the brick buildings in the city were shattered. Mr. Fitzherbert's free and bonded store in Farish Street collapsed, but was subsequently restored by Mr. Plimmer without taking off a slate. The front wall of the Colonial Hospital, in Pipitea Street, was partly thrown out. A new brick building on Mount Cook had to be stopped in consequence of the shake. Hickson's store, which was also damaged, is still standing at the corner of Old Custom-house and Cornhill Streets. The Wesley Church, in Manners Street, was also thrown down. These were all the brick buildings injured. It was worthy of note that no wooden buildings were injured. The brick buildings were built then of a mortar composed of shell-lime and clay from Barrett's Point, which with age was reduced to a powder. Old intelligent pioneers assured him that, if the buildings had been constructed then as they are now, little or no damage would have been done. A sensational report of this earthquake was drawn up by Mr. Eyre, Lieutenant-Governor, which had a most alarming effect, and greatly retarded colonisation for a long time. With respect to the shook of 1855, he had been assured that no brick buildings were totally wrecked, though some few were injured—in fact, buildings erected before that time were standing yet. Since Mr. Maskell had read his paper the author had visited them, and found them
in good order, and answering the purposes for which they were erected. As to the question whether it was possible to erect brick buildings in New Zealand, and in Wellington in particular, capable of resisting earthquakes even of a severer nature than any they had hitherto experienced, he said he had no hesitation in saying that it was, and that buildings of such a character were erected. As Mr. Maskell had referred to several of the buildings erected under his (Mr. Turnbull's) care, he desired to say something respecting them. Concerning Messrs. W. and G. Turnbull's building on the reclaimed land, he stated that he had suggested floating foundations, as they were not costly, had stood the earthquakes well in San Francisco, and the filled-in earthwork between the rock below and the foundations of the building would act as a cushion, and deaden the stroke of an earthquake should one occur. This foundation consisted of cross-planking and a double row of beams all bolted together. The motive for this system of foundation was that when a shake occurred the heavy beams and planking would carry the superstructure along with the oscillations of the earthquake. When this building was in course of erection an earthquake occurred. This was at a time when our Solons were in session; and many of them rushed down to the reclaimed land expecting to see the buildings in ruins, and he supposed they were somewhat disgusted to see the mechanics at work as if nothing had happened, so little knowledge had they of the strength and tenacity of brick buildings. He mentioned this to show that even the siftings of the New Zealand population had little faith at that time in the stability of brick structures in Wellington. He entered into the question of cements, and the most suitable, in his opinion, to be used here, recommending “béton aggloméré.” Referring to the qualities of New Zealand timbers, he said they had little or no fibre, and broke short without warning. Some of the varieties were never seasoned, and the most useful and best shrunk the end-way, to the disgust of the architect and builder. Mr. Maskell said that the National Mutual Association buildings had a heavy cornice to their projections, and that the arches did not curve into the abutments. He said the same of the Post-office. Now, in each of those buildings the cornices projected just 6in. less than, according to the best authorities, they should do in order to produce true architectural beauty. He noted this to show that he had erred on Mr. Maskell's side—if error it was. In his opinion, however, the line of 6in. more could have been touched with perfect safety, as the roof behind was infinitely more than a counterbalancing weight, as was shown by the naked walls of the Post-office having stood for the last eighteen months without floor or roof, and after being exposed to extreme heat. So far as the arches were concerned, they all curved to the abutments, for the reason that there was nowhere else to butt them to. For the safety of the building now he could not answer; but before it was destroyed by fire he would have stood in any part of it during the severest shakes he had felt here or on the west coast of America, and have had perfect confidence in his safety. He denied Mr. Maskell's assertion that buildings were not put up in Wellington to resist earthquakes. Here, as elsewhere, money entered largely into the qualities of a building; and, speaking personally, he used to the utmost every precaution that the money at his disposal would allow him, and he was sure that his contemporaries would do the same for their own sakes; therefore it was neither just nor fair to an honourable profession to make such an assertion—not even by a gentleman who confessed that he knew nothing about it. He agreed with Mr. Maskell that the Corporation by-laws ought to be more explicit. There was not one word about the quality of the brick or of the mortar, or how they were to be laid together, and other important matters. Clearly, their City Fathers had paid more attention to the fire-insurance agents than to earthquake-agitation. He thought it was time that the city should have a Building Inspector who
knew something about building-construction. He suggested that on the reclaimed land floating foundations should be used as a protection against earthquakes. The bricks should be hard and square, and well wetted, and the mortar should be composed of what is called “béton aggloméré” in France. Hoop-iron should be built in the walls at short heights, and the buildings girt with bond-irons instead of wall-plates. The joists should be a fifth of their depth in thickness, and supplied with wrought-iron anchors. Mr. Maskell had told them that he had taken opportunities of looking at some of the brick buildings in the city, and had found that the greater part of the theories of Professor Milne had been neglected. He hoped that he (Mr. Maskell) would now admit that in these visits his looking was only superficial, that he only saw regular openings one over the other, instead of scattered ones, that the arches were not curved into the abutments, and that there were some projections which did not please him. He hoped that, after having heard the foregoing general description of the construction of the buildings under consideration, Mr. Maskell would see that the wrought-iron built within the walls, and the iron-bound connection that the floor and roof had with the walls, formed such a tower of strength as even Professor Milne never dreamt of. All his (Milne's) theories were mostly on the face, and no part of the framework. This system had been followed in the building he (Mr. Maskell) had criticized. It was a mode of construction that had proved eminently efficient in San Francisco and along that coast, and was in use with the architects there, a body of gentlemen represented by every nation in Europe, as well as America, and who had begun the study of earthquake-proof construction long years before the name of John Milne was known to the scientific world, who were still continuing the study, and on this subject were, in his opinion, the best authorities on the face of the earth. In conclusion, he hoped there was nothing in Mr. Maskell's paper or Professor Milne's book that would eliminate the faith they had in their adopted country, and that they would continue to hope that they would experience no more severe tremors of the earth in the future than they had in the past.
Mr. Donaldson asked the author whether the wooden buildings stood the shakes experienced in 1848 and 1855 better than those of brick or stone.
The President regretted that Mr. Turnbull had made the question a personal one. He (Mr. Maskell) had carefully avoided that; and his only object in presenting the paper was to draw public attention to an important matter. He did not desire to defend Professor Milne, who could stand up for himself; but if he was allowed he would differ from Mr. Turnbull's opinion of that gentleman. As far as his (Mr. Maskell's) reading went—and it was not that of a few days—no name stood so high as that of Professor Milne upon such matters. He combated Mr. Turnbull's arguments at some length, and pointed out that the effects and results of earthquakes were incomprehensible. Earthquakes seemed to knock buildings down or leave them alone just as they liked. A number of buildings on one side of a street might be knocked down, while others on the opposite side would be uninjured. He considered that Mr. Turnbull had given up the whole question—just as an architect who had written to a newspaper in reply to his (Mr. Maskell's) paper had done—by expressing the opinion that we were not likely to again experience destructive earthquakes. Those who thought that were perfectly welcome to their opinions. He did not believe that destructive earthquakes might not at any time occur in New Zealand; and he explained that the whole of his paper was based on the supposition that what had happened before would probably happen again. He quoted some notes on the shock of 1848, written by Mr. W. Fitzherbert, who stated that “the earth in some parts was moved in waves averaging about 12in. in height.” He would like to know how their brick buildings would fare under those
circumstances. Mr. Fitzherbert had further stated that in the brick buildings which were thrown down the mortar used seemed to make very little difference. In many cases it was bad; but where good cement had been used the only difference noted was that the bricks, instead of falling singly, came down in blocks of eight or ten together. This would probably not be much more satisfactory to the inmates than a rain of single bricks. Mr. Maskell also quoted from some notes on the same earthquake given by Mr. H. S. Chapman (afterwards Judge Chapman), in an article in the Westminster Review, détailing the damage done. In this article Mr. Chapman expressed the view that brick buildings in Wellington might be safe enough if of one story only, or well tied together by bonding-timbers, but not otherwise. Mr. Maskell expressed his belief that, if the recent shock experienced in Canterbury had occurred here, one-half the large buildings of brick and stone would have been very much injured, if they had not fallen down. Further, as a proof that men of eminence did not think the earthquake of 1848 a light matter, and considered great precautions necessary for the future, he quoted from a letter written in 1888 to the Institute of British Architects by Mr. E. Roberts, who was attached to the Royal Engineers in Wellington in 1848. Mr. Roberts after that built a new gaol on Mount Cook, and took the precaution of constructing it with specially large bricks built in a perfect cage of iron bars placed 5ft. apart, and running up from the foundation to the roof. This gaol is of no great height. Surely in structures such as we have now, of three or more stories, much greater precautions than those of Mr. Roberts should be adopted.
Mr. Turnbull, in reply, said that he did not mean to make the question a personal one. He explained that the Roman cement referred to was not equal to our present cement. He could not say much as to now the wooden buildings had stood during the severe shocks.