ROOF COLLAPSES

Gisborne Herald, Volume LXVI, Issue 20107, 29 November 1939, Page 11

ROOF COLLAPSES

30-TON STEEL FRAME NEW AIRPORT HANGAR EXTENSIVE DAMAGE WALL GIRDERS BUCKLED (Per Press Association.) CHRISTCHURCH, this day. Without warning, the 30-ton root structure of the partly-completed steel frame of a big hangar at Harewood airport collapsed yesterday afternoon. Weeks of work have been undone and it is feared that the damage will be great, as the roof girders and part of the steel frame erf the walls were considerably buckled when the mass of steel fell.

Two mon were on the structure just before it collapsed and several were working nearby on the ground, but none was injured.

The length of delay on the building and the amount of the damage will not be known accurately until it is known how much of the material in the hanger has to be replaced.

An investigation of this will be commenced to-day by Mr. C. W. Turner, chief designing engineer of the Public Works Department, Wellington, who was directed to leave for Christchurch last night after being notified of the accident. The cause of the collapse of the structure is unknown. When inquiries were made last evening, Mr. F. Langbein, district engineer to the Public Works Department, said that the collapse of the roof was probably not caused by a fault of the design of the structure nor by the weakness of the steel components or flaws in the metal. The most probable explanation was that the method adopted in erecting the arched structure of the roof had some weakness in it. Buildings Elsewhere Numerous buildings of this type, Mr. Langbein said, had been built in Australia and had apparently given no trouble, and there was at least one precedent in New Zealand,- since a hangar with identical roof construction had been erected successfully at Auckland.

The contract for the construction of two hangars at the airport is let to B. E. Moore and Sons, Limited, Christchurch, and the sub-contract for the fabrication and erection of the steel works is‘let to the Wellington firm of Cable and Company, Limited. The length of each of the hangars is about 255 ft., and the span is 126 ft., the maximum height from the ground to the roof being about 35ft.

Twelve Girders Erected The building of the roof is on what is known as the tvdarch principle and consists of steel ribs bent into the I form of an arch. Ribs or girders arc [spaced at intervals of about 15ft.. and , about 12 of these girders had been erected, after several weeks’ work, by yesterday afternoon, their combined weight being about 30 tons. Tlie steel frames supporting the arch and carrying (lie walls had their upper parts damaged when the heavy structure of the roof fell and the arched girders themselves were considerably buckled. Work on the hangars, each of which, it is believed, will have cost £IO.OOO to £15,000 on completion, started a few months ago and was expected to finish early next year. The second of the hangars is also | under construction, though the work ,on the arched roof has not yet been started. Difficulty in procuring steel to replace the damaged parts of the hangar may be encountered, and consequently will Ibe a factor in delay in I finishing.