Malayan timbers are considerably stronger than British or Scandinavian and a comparative list of the timbers most commonly used is shown below.
fc
The constant "a"
2800 (Morley)
* E
Timber
ƒ
E
Timber
ƒ
E
White deal 900 1,200,000 Spruce
Kapur
900 1,200,000
Meranti
1700 1200
(dark)
Redwood
1000
1,200,000
Balau
Douglas fir 1200 1,500,000
Chengal
2560 2500
Pitch Pine
Oak
1200 1,500,000
Keruing
1200 1,200,000
Meranti
1450 1000
2,310,000 1,640,000
3,210.000 2,630,000 2,170,000 1,350,000
Ewart S. Andrews recommends 2000 so the mean of 2500 has been taken.
=
The safe stress fc is taken as 930 lbs. per square inch with a factor of safety of 7. The ultimate breaking stress per sq. inch = 930 X 7 6510 lbs. (See trade leaflet No. 7). Example 1-To find the safe load for a column 5" X 5′′ X 8'0" high pin jointed both ends.
930
(light)
P
1 X 1
COLUMNS & STRUTS.
(KAPUR)
Pin jointed ends.
2500 (
8X12 2
930
1--1.72
343 lbs. per sq. inch,
1.442
Total load = 343 X 25
=8560 lbs.
The columns and struts shown in Tables are based on the following formula vide Rankine.
p =
p
fc
fc
1 + 1
a
2
()
= Safe load per square inch.
Safe stress per square inch. Least radius of gyration,
Effective length,
а
Constant.
Example 2-The effective length Apply same formula.
=
1⁄2 given height.
930
930
= d
= 646 lbs. per sq. inch,
1+ 1 4X12 2
1÷44
2500 1.442
Total load 646 X 25
-
16,150 lbs.
MODULUS OF
PLASTICITY
IN SENDING
(LBS. PAR
HAME OF
TIMBERS
(INCH LBS)
DRY PLACE UNDER COVER
ALLOWABLE WORKING STRESSES FOR MALAYAN TIMBER (EX. MALAYAN FOREST SERVICE TRADE LEAFLET NO. 7)
SO. IKEN)
OUTSIDE NOT IN
CONTACT WITH THE GROUND
IN COMPRESSIOH PARALLEL (LBS PER So INCH)
ONY PLACE UNDEN COVER
OUTSIDE HOT IN CONTACT WITH
THE GROUND
CHIAR ALONG GRAIN
(LBS. PER SO, IN.)
BALAU
2,670,000
2,750
2,550
2,150
1.900
165
CHANGAL
2,630,000
2,000
2,500
2 500
2,200
195
KERUING
2.170.00D
1.700
1.450
1,400
1. 250
105
KAPUR
1,310,000
2,000
1,700
1.650
1,450
120
МЕЛАНТІ
1.550,000
1.200
1,000
900
800
6 5
X
#
1.725 x 32 425 =
26.12.5 X 6.350 938.25 X 1075.32=
+
170X$250
365
$125-10%
1,4753 X
295
62.125
0237
365
...if it's
ANSWERS
you need...
BORNEO SUMATRA
TRADING CO., (MALAYA) LTD.
INCORPORATED IN THE COLONY OF SINGAPORE
WITH LIMITED LIABILITY)
BUSINESS MACHINES DEPARTMENT
4TH FLOOR. CHAN WING BLDG..
MOUNTBATTEN ROAD
TEL. 4396
KUALA LUMPUR
FRIDEN Fully Automatic Calculators will produce accurate answers to your figure work problems. Discover for your- self, how anyone in your office can operate this modern cal- culator, with less than 15 minutes instruction on your own problems. Just telephone or write and arrange for a demonstration. FRIDEN Calculators are now available to every business. Replace your worn or obsolete equipment with easy-to-operate FRIDEN Fully Automatic Calculators.
FRIDEN CALCULATING MACHINE AGENCY
SINGAPORE
41 ROBINSON ROAD
P. O. BOX 418
TEL. 82275/6/7
EXT 9
PENANG
160 WELD QUAY
PO BOX 312
TEL. 1278
74