February_1968 — Page 15

July 1966. Part of the floor slab for the third storey is in position

completed on June 9, taking some 40 days from May 1, when assembly started.

During the months of June and July, work was held up on a number of occasions due to the heavy rain and severe tropical storms, including Typhoons Lola, Mamie and Ola. However, little or no damage was caused to the actual work, including the casting and assembling. By mid- June, six weeks after assembling work was started, the average production still remained at twenty panels.

The contractor then decided to introduce an incentive scheme where- by small teams of workers were paid on a piece work basis instead of direct labour, with a team consisting of a crane operator, a welder, a plasterer, three female worker.

assemblers

and

a

teething troubles with Despite teething plant and labour and methods, pro- duction immediately improved, and during the first two days, the number of finished panels jumped to 32 com- pared with the previous average of 20. The obvious reason was, of course, the workers voluntarily work- ed longer hours and it was gratifying to note that the site staff was able to maintain the standard of workman- ship and quality control of the concrete used without any difficulty.

The improved rate of progress was maintained all through the summer of 1966 until mid-August, when a long dry spell began. The heat was felt particularly by the workers at the curing chamber on the casting yard, where work was carried out on steel flooring. A covered casting yard would have improved the situation immensely.

Efficiency, however, was high and occasionally, 50, 60 panels would be completed during a working day until, early in September, due to frequent conflict between the teams and the contractor's site staff, the piece work arrangement was ter-

Far East Architect & Builder February, 1968

minated and with the exception of some difficult workers, the rest were re-employed on a regular pay basis, (i.e. HK$15 per day).

All precasting work was completed by September 22, assembly on September

28, and arrangements

were made for the load test to be carried out early in October, 1966.

Load Test

Being an experimental scheme, and the first of its kind, one of the con- ditions of approval by the Building Authority was that a satisfactory lateral loading test should be carried out on completion of the structural work, and preparatory work for this commenced with the arrival of six Japanese engineers from the technical research department of the Taisei

Т

Construction Co. at the beginning of October.

The installation of testing instru- ments and recording equipment was completed within a few days and preliminary tests to ensure the ap- paratus was in full working order took place on October 10 and 11. These were followed by full scale lateral loading tests, witnessed and verified by officials of the Buildings Ordinance Office and other P.W.D. sub-departments.

The object of the lateral loading tests was to determine the behaviour of the structure under strong wind conditions, by checking the rigidity. strength and safety factors from the results of the instrumentation records and analyses of displacement due to wind load to which the building may be subjected, simulated from the inside.

In order to carry out the test to the completed structure, it was neces- sary to pre-determine early in the job where and how to take the reaction. As the block has a central corridor with 7-person and 5-person flats on each side, it was convenient to separate laterally the portion of building to be tested into two free- standing sections using the side with 5-person flats as a test block and the other with 7-person flats as a reaction block.

The two test blocks were completely separated from the adjacent portions of the building both vertically and horizontally except at the foundation. This was made possible by the ex- pansion joint on one side whilst on the other, the floors and beams were cast 11 in, shorter with the reinforce- ment bent up so as to facilitate rein- statement after the test. Temporary supports were provided to the floors and beams on the free-end side during the test.

In order to simulate the wind

TA

September 1966. Babcock & Wilcox GH 75 HVZ tower crane with 33 metre boom lifting a panel from the curing bed to be stacked to await assembly. Moving gantry used for hoisting and placing concrete is also shown

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