USE OF BRICKWORK

Dominion, Volume 29, Issue 138, 6 March 1936, Page 8

USE OF BRICKWORK

Resistance to Earthquake BUILDING PROBLEMS The future of brickwork in New Zealand, in view of the frequency of earthquakes, is discussed at length in au article in the February issue of the journal of the New Zealand Institute of Architects. It is stated that the result of earthquakes at Murchison, Hawke’s Bay and Pahiatua in recent years lias showu that materials of small unit construction without reinforcement afforded a resistance to the destructive forces in varying degrees. While the instances of badly constructed brickwork with weak mortar and the non-adherencc of mortar to bricks were very much iu evidence as the cause of failure, there were many instances of soundly constructed brickwork which, without any definite or conscious attempt in their design to enable them to resist such shocks, showed very considerable stability. There was also some evidence to show that many of the failures of brickwork were more due to its combination with other materials in such a way as to cause mutual destruction than to its own instability; whereas instances of brickwork suitably combined with other materials and remaining practically undamaged were also numerous.

“The great adaptability of brickwork to the construction of all types needs no emphasis—it is a home-truth apparent to all who have to do with structural matters. Its advantages as compared to concrete iuAiertain portions of buildings are well known. But the problem of how to make it thoroughly safe and stable —or, shall we say, as stable as concrete under the like conditions of use—4s one that needs solution if it is to be used extensively. Problems In Concrete Work. “One of the difficulties in concrete work is the tendency of thinner sections to develop expansion cracks and another is to provide it with a face which will increase its weather-resis-tance and also provide a good architectural character suitable to the location and purpose of the building. The problems of heat insulation, condensation of moisture, and the provision of a good key for plaster are also inseparable from the use of concrete, though not insuperable. Most of these problems become less if brickwork can te substituted for concrete with equal structural efficiency in such parts of the structure as are adversely affected by them. “These difficulties are, in the larger buildings, most apparent in the case of panel walls between the framing. The new Wellington railway station, which is being constructed of steel frame ami reinforced concrete frame, is to have its panel walls constructed and its piers faced with 9in. brickwork reinforced at 28Jin. centres vertically and horizontally, the bricks being specially made with a recess so that they may be without difficulty laid round the vertical reinforcing

rods. The outer face will be in 9iu. brickwork, and where the panel walls occur there will be a cavity and an inner wall of 4lin brickwork. This was decided ou after tests made four years ago on two 9in. walls, 12ft. wide and 10ft. high, one being in plain brickwork, with “briekfor” bonding every sixth course, and the other of similar brickwork reinforced with Sin. rods vertically at 36iu. centres. The plain brickwork showed astonishing resistance to impact blows, but: tlie reinforced brickwork was 2S per cent, stronger. The tests were considered to be conclusive as to the stability of well-built 9in. brickwork for panel walls in framed buildings. Economical Production. ' "But if bricks are to be produced economically they must be manufactured in adequate quantities to keep kilns in continuous operation. Consequently they must be made adaptable to all circumstances of building, and must be capable of construction with such stability and resistance to lateral forces of earthquake that brickwork may be safely recommended as equal in resistance to concrete. In other words, they must be capable of reinforcement, So that they can be used for smaller and unframed structures—more .particularly for houses. This naturally involves the problem of reinforcing cavity walls. • “Attempts are being made to arrive at a solution of the problem, and the ideas show great promise of success if feasible with economy. It might perhaps be suggested that a comparative test of a brick cavity wall so reinforced and with a reinforced concrete band on top and a 6in. concrete wall might be useful, and would tend to inspire confidence in the profession, as well as among the public. “The question of confidence is so vital to the success of any material, and confidence iu good materials is so often shattered when they arc used wrongly. Where there is a question of safety of life and preservation of property, confidence can be established by thorough examination and research, which will enable the architect to recommend the use of a material with more assurance.

“The future of brick-making—apart from this question of confidence in its use—is bound up with die requirement of economy of construction. It is a foregone conclusion that if the cost of brickwork under such improved methods of use is likely to be unduly high in comparison with that of concrete, the use of brickwork will not be greatly stimulated. If increased manufacture of bricks is to be contemplated, it is essential that the cost of the material must be relatively low, and if the cost is kept down to the minimum there will bo a consequent increase in the demand. To put it briefly, provision for reinforcement may inspire confidence iu brickwork, but economy of cost will secure larger demand and turnover.”