Industrial Building

Sun (Auckland), Volume III, Issue 765, 11 September 1929, Page 14

Industrial Building

EXPERT POINTS THE WAY Owner, Engineer and Architect SOME modern ideas on industrial building construction were given recently in a lecture by Mr. R. A. Campbell, formerly professor of structural engineering at Canterbury College, before the Canterbury Employers’ Association. Mr. Campbell dealt with the modern type of concrete construction and the importance of co-operation between owner, engineer and architect.

The design of the modern industrial building, be said, was the joint product of the architect and the engineer. Before a beginning could be made on building design it was necessary that the owner or client should know, or, with the assistance of the architect, should decide, upon exactly \vh;ilie required. The old type of timber building, after completion, could be altered considerably to meet the requirements of the owner and to provide for details which had been overlooked or forgotten when the drawings were made. Modern concrete and steel structures could not be altered to any great extent after completion, and it was therefore essential that all the thinking necessary to produce the required result and to provide for all the various services, details, loads to be carried, and future possible extensions, should be done before, and not after, the work had been put in hand. It would be easy to quote instances where great inconvenience had arisen or considerable expense had been incurred through the want of forethought on the part of the owner, architect or engineer.

MANY PROBLEMS The owner had many problems to decide. The first, and perhaps the most difficult, was to determine to what height it might be necessary to carry the building in the future, due to expansion ot' business or increase in the demand for rentable space in the upper floors. A client who wished to erect a two or three-storey building and make provision for adding several more stories in the future must sink a considerable amount of capital in making the foundations and columns strong enough to support the future extension, which might not be required for years. On the other hand, if no provision were made for going up in the future, and in a few years after the first stories -were erected expansion of business or other causes called for higher building,’ it mjght not be possible to strengthen up the sub-struc-ture sufficiently to carry the extra weight, or, of possible, it would always he very expensive and not as good a job structurally as it would have been had a lesser amount of money been expended in the first instance. A decision must be arrived at by the owner after the estimated cost-figures had been submitted to hint. The next difficult point to be decided

was what load to the square foot should the floor be designed to carry. Tbe office building which could not very well be used for other purposes presented an easy problem, as the loading was not generally fixed by city by-laws. Some by-laws insisted that a marble block, showing the live load the floor of a building was capable of carrying should be set in a prominent place. In the past where serious failures of concrete buildings had occurred it had sometimes been found that the floor designed for office loading of 801 b a square foot had been loaded to three or four times that amount, and when there was an inquiry, it was shown tha.t there had been no record of tbe load used in design—nor were the original plans and calculations available to prove that over-loading had taken place. Mr. Campbell referred to the hurry of some owners to have the plans rushed through, by calling for tenders within a certain time. This was not fair to either the architect or the engineer, who would not be able to give tbe requisite thought to the plans. And rushed plans made for errors. FERRO-CONCRETE COLUMNS The speaker was of the opinion that the ferroconcrete columns of any building were the weakest parts of a purely reinforced concrete building, and w'ould fail before any other part were the building loaded to destruction. Structural steel columns were to be advocated for all buildings over four stories, aud in all cases where they were used they should be encased in concrete to prevent fire risk. Mr. Campbell dealt at length with the construction of factory buildings, particularly from the point, of view of the floors, of which there were three types—the beam and slab floor, the fiat slab floor, and the hollow til© floor. The advantages of the lastnamed type were many. It was possible to increase the slab depth very materially without increasing the weight, thus' obtaining very great strength and much larger spans than would be possible with a solid slab. It was fire-resisting, and soundproof, _ and gave the maximum diffusion of light; the arrangement of reinforcement in both directions gave gi eat strength against earthquake stresses, aud reduced to a minimum the risk of fine cracks which gave , leakage trouble in concrete roofs.