November_1967 — Page 17

is five times this height and has a light steel frame structure, wind re- sistance was a most important factor.

1. Wind load on the structure

(a) Assuming the wind velocity at the height of 147 metres is 82 m sec, it means that the ac- celeration of El Centro earth- quake 330 gal is equal to a force of 82 m sec. wind velocity on the structure (without bearing

wall).

q

=

416 kg m2

where q means the velocity pres- sure of wind.

(b) A model of 1 500 scale which simulated the configuration around Kasumigaseki district, was made and placed in a wind tunnel under such velocity dis- tribution as will occur in the city streets. The wind force coeffi- cient C was determined.

(c) The wind load P is shown by the

following equation

P c q A

where A is the wall area of the building exposed to the flow,

2. Wind load on curtain walls

Wind data for skyscrapers is very scarce in Japan. The new structural regulation stipulates that the wind load on a structure should be deter- mined through experiment. Some data of wind velocity observed on the sea and in the field is available, but data on wind blowing in the streets is unavailable.

I therefore looked to details of the highest wind velocity observed so far both in America and Japan. On August 27, 1949, the maximum in- stantaneous wind velocity observed during a hurricane at Lake Okeecho- bee, Florida, was assumed to be about

Fig. 2. Cross section

36F

35F 34F

33F

32F

31F 90

SIGHTSEEING TOWER

·RESTAURANTS

30F

29F

28F

27F

26F

25F

24F

OFFICES

23F

22F

21F

20F

- MACHINE FACILITIES

19F

18F

17F

16F

15F

14F

13F

12F

11F

10F

OF

BF

-OFFICE

7F

6F

5.F

4F

3F

SHOPS

2F

LOBBY

1F

SHOPS

81

M8B2

B2

83

PARKING

-MACHINE FACILITIES

WAREHOUSES

TOKYO CLUB BUILDING

SIDEWALK

OUT

Fig. 2a. 2nd floor plan

Far East Architect & Builder November, 1967

PLATFORM

IN

FOR HIGHWAY INTERCHANGE

BOARD OF

AUDIT BUILDING

PLAZA

10% OUT

50M

·PEDESTRIAN ACCESS

»VEHICULER ACCESS

43