REINFORC ED CONCRETE.

New Zealand Herald, Volume XLIII, Issue 13202, 13 June 1906, Page 7

REINFORC ED CONCRETE.

A correspondent, signing himself "A, Visitor," writes; — Having resided in your charming city for a brief period, various matters have Mm# under my observation, and ideas fcavo occurred to ma, some of which might prov# of interest to your readers. I will not crave space* to dwell upon ibe natural beauties of Auckland and the harbour You have heard all about that before. The enterprise of your present Harbour Board is manifesting itself in a manner worthy of commendation. The pioneer wotfc which that corporation is doing in building wharves constructed of rein Forced concrete « a matter about which the citizens may well be congratulated, as it will ultimately provide Auckland with thos*, extensive utilities of a most suitable, safe, and economical character. Those who understand that form I of construction are fully agreed that it is of the utmost importance to adhere rigidly t« J certain well-defined general principles, and j to see to it that the greatest care is exercised in the carrying out of what may appear to tho inexperienced as mere minor derails. The near-enough line. of thought and action must not eiuoi there. It is to be remembered, too, that there is practically co limb >0 the combinations and methods that msv be employed in the skilful use of reinforced concrete, and a good deal of needless mystery has been" made to surround proposals for its use for a variety of purposes. That form of construction is admirably suited for all kinds of buildings requiring little or no expenditure for maintenance, besides being proof against the destructive agencies of tire and decay Those, excellent qualities enable it to be used for a great, variety of structures, having due regard to economy and efficiency. The number _ of fires iii Auckland is a cati?.« for anxiety and regret, but can such be wondored at in view of tiie materials used? Wood was the natural material with which to build in the earlier periods of colonial growth, and much credit is due to those -who have, attained so much result and effect by working in that material. Does not. the fact that your forests are being rapidly devastated, »nd that in a very few years New Zealand will have to import, instead of export, timber, suggest itself to your people, and particularly to your legislators, and that to allow these beautiful trees, which shado and adorn many of your gorges, main roads, and sea frontages, to be destroyed willcauso you irreparable, loss? Your Tourist Department and scenery conservation societies should receive the cordial support of all got*' colonists in their efforts to prevent anj further denudation of that kind. It is ot> vious that the use of wood in buildings cannot long continue, front the standpoint d 1 diminishing supplies, and gradual increasn in cost alone, as well as from the growing desire to overcome the disadvantages! attach* ing to its uses 011 account of the ravages ol worms, natural decay, and fire. Surely, then, the time has now arrived when, tho value of human life and the safety of dwellings, stores, public and private* building*, as well as the property oontained therein, should receive, the fullest measure of consideration. The economy of reinforced concrete when scientifically applied has already been fully demonstrated, the extra cost over that of wood and brick being hardly appreciable, and under certain circumstances would be rather less costly. Brick walls with wood lining and wooden partitions cannot, be considered satisfactory or safe, and have, I understand, caused more than one calamity in Auckland. :

Your city is now manifestly passing through a very important transition, from comparatively simple, into the more complex conditions due to its growing requirements, and such as must, accompany lha progressive lines of municipal policy, which the Herald lias recently sustained, and which the citizens have confirmed by adopting those various constructive proposal#. It is all the more necessary then to consider carefully modern methods: and may I here say that your enthusiastic director of technical education ought to be most helpful in that direction, a? a good work is un- . doubtedly springing up in your midst under his zealous administration. It is certainly worthy of notice that in other countries, e.g., the United States. France, Italy. Switzerland, Germany, and more recently in England, large and important buildings and other structures have been and are being erected of that material. They are considerSd more economical and durable, than those built by the employment of the older materials and conventional methods. Your City Council, teo, have recognised the advance that must be made, and have taken a wise step by engaging a new city engineer, who, it is expected and hoped, will prove to be a gentleman of high attainments in his profession. He will surely endorse my statements; and, from the standpoint of the scientist, willingly and fully approve the employment of reinforoed ooncrete for buildings, when such have been designed iu accordance with the results obtained from modem research and experience. The quality of the locally available materials Is excellent. They are most varied in oharaoter, and equal, if not superior, to anything obtainable in most other parts of the world. Th« various sands, shingles, metal chips, scoria:?, and pumice, afford a wid» field for the selection of Aggregates, suitable, when properly classified, for a great variety of purposes in reinforced concrete structure*. In (.lie supply of excellent lime and cement, • locally made, there appears to be literally no limit.

Now allow «i.» to briefly amplify the matter, and to refer a little more explicitly to some of the ndvaNtages of the material. Reinforced concrete is undoubtedly the best material for fire-proof/ construction, since the concrete protect!! the iron or steel skeleton embedded therein, by reason of it« low conductivity of heat. This skeleton (and there are many varieties of form of such skeletons) in turn has a marked effeot in preventing the concrete from c racking, either under the influence of the heat of the fire itself, or under the rapid cool ins action, of the water thrown upon it. Buildings of reinforced concrete are, again, usable directly after a severe conflagration. That has been proved over and over again, and it must be conoeded that this is an immense advantage to all concerned— to the householder, the merchant, the banker, the insurance companies, and, under the law of waste-prevention, to the whole community. The internal fittings and contents of a compartment may have to be replaced, but the building itself would need little repair, if any. For the same reason the operations of the fire brigades, are made easy, safe, and effective. The American and European fire brigade officers are strongly in favour of the employment, of reinforced concrete for all kinds of buildings. The monolithic nature of reinforced concrete give* a strength to those structures unknown prior to its introduction, and minimises the damage that all structures are liable to from 'displacement of settlement, vibration, or earthquake.

It is, perhaps, not necessary to dwell any longer on the excellent. qualities and advantages of this material s when scientifically applied, and in accordance with modem methods. The present city by-laws appear to make no specific provision for the use, or substitution, of reinforced concrete, excepting through the prudent exercise of the pohvers set forth in the " modification clause," which was no doubt framed with a. view to meet such contingencies. It would ho highly desirable to bare the matter brought tinder review by the City Council as? .soon as the new city engineer takes office, with a view to permit the use of reinforced concrete in a way that would give to pro-perty-owners the fullest, measure of benefit accruing to its adoption. Those matter* cannot, fail to appeal to, and be appreciated by, the present. Mayor and councillors, as be-ins; quite, in keeping with the progressive spirit manifested by them recently in another direction. In conclusion, sir, allow me to say that the city of Auckland bids fair to become a largo arid important city commercially, and. in some other way», the leading city in New Zealand. It behoves its citizens to make it possible for the local architects and engineers to build the Greater Auckland in a way that will compare fairly, and comply reasonably, with the developments that havo taken place in similar cities in Europe and the United States. The writer has had opportunities to witness these developments, and to make a special study of the various systems of reinforced concrete construction, and wishes your readers to discriminate between that and the steel-framed building* instance, the local power-houseas the advantages before mentioned do not accrue to throw structures in the sense claimed for reinforced concrete buildings. Your country is truly a wonderland, and has greatpotentialities. Its people havo many privileges, and must acoept corresponding responsibilities, and one of those is to reflect purpose, truth, and wisdom, in all, their undertakings. Should my passing reference© in any way help them,. I shall have been well ' pleased; and will be still better pleaded io return some day and find that good use has been made of your marvellous opportunities.