NOTES ON EARTHQUAKES AND THEIR RELATION TO BUILDING CONSTRUCTION IN NEW ZEALAND.

Progress, Volume I, Issue 2, 1 December 1905, Page 28

NOTES ON EARTHQUAKES AND THEIR RELATION TO BUILDING CONSTRUCTION IN NEW ZEALAND.

By F. de J. Clere, F.R.1. 8.A

SECOND PAPER. The following are notes on the Building Regulations for Ischia, Italy. " A solid foundation should be obtained so far as is technically possible." " Construction of iron and timber are much mo:e safe than those of simple masonry" " Walls built of brick are better than those of stone." " Vaults and arches of masonry above ground should be prohibited." " Buildings should not have more than two stones and a cellar." " Composite construction of iron and masonry cannot be considered with regard to safety, comfort and durability as adapted to countries threatened by earthquakes " "In the province of Belluno a great many buildings have been strengthened by means of keys, chains and iron bands." " In the Levant buildings are frequently framed together, and then covered on each side with a trellis of laths or canes, which are in their turn plastered." " According to a long experience, cellars may be constructed with ordinary masonry." Timb?r- framed buildings, covered with rough cast, are strongly recommended ; the danger from fire being prevented by anti-igneous preparations, After the terrible earthquake in Lisbon of 1755, this timber construction was insisted upon, and ths number of stories, above the soil, was limited to two. The timber used was fir from northern Europe. When the law was relaxed, timber buildings of four or five stories were built. In Japan this system of " barrack masonry," as it is called, is very extensively used, and the rough-cast surface offers the greatest resistance to flames. In lower Chili, it is the custom to construct buildings of only one story. Bricks are notched to fit the timber framing. In Lima the ground floor is generally of strong masonry, and when there is an upper floor it is of very light timber.

In Calabrn houses, which were not built on the "barrack" system, contained a special eaithquake- proof room with an internal frame of iron bars, in which people could take refuge. For roofs complete trusses should be used and not mere rafters resting on walls. Embossed ornaments likely to fall are forbidden for ceilings. Vaults (o reined fioois) made of stone or brick (exercising thiust)- are forbidden in any part above the cellar. *■ Chimney flues which reditee the walls to less than the regulation thickness are forbidden. In the regulations for the Ligunan Commune the rules drawn up are largely of the nature of ordinary good building legulations, and in most respects are similar to those of New Zealand Squired stones are insisted upon, but the assumption is that ordinary hme-mortar is used. Flints are forbidden, as mortar does not well adhere to them. The building laws of Manila and of Ischia contain many other regulations than those noted herein , but they relate largely to the power and duties of the controlling bodies, or have reference to matters that are not applicable to the conditions of life m New Zealand, or to the materials which are in use in this part of the globe. It must, I think, strike the reader that the building regulations are exceedingly crude , and, if similar ones become law in a progressive country, they would tend to check improvements m general construction. Then the thickness required for walls must be an indication that the masomy is exceedingly bad The sweeping condemnation of composite construction is certainly against modern ideas and m direct contradiction to those of Ischia, where the " barrack " system is strongly recommended. In some parts of Central America, I understand that walls are formed by posts fixed into the ground and cased m large sun-dried brickseach buck being made in lengths to cover the distance between the centres of the posts, a groove in each end containing half the timber. After my 27 years expeiiencem this colony, and after reading all I can find on the subject of earthquakes, I have come to the conclusion that the aim of our laws should be to promote strong buildings, and that very httlj else can be done to counteract the effects of earthquakes Brickwork is better than rubble masonry in many respects, for the strength of the whole wall is even, and owing to the proportion and shape of each brick there is no wedging tendency m any part of the wall On the other hand rubble formed with strong cement has much of the nature of good conciete, and, as such, its use ought not to be forbidden {To be concluded.)