2 BULLETIIs^ 1259, U. S. DEPARTMENT OF AGKICULTUEE. 
shall supply testing machines of the proper type and 
capacity and shall provide all facilities and labor inci- 
dental to the making of tests. In all tests involving the 
determination of tensile and compressive strengths the 
ultimate strength, deformation, and other pertinent 
data shall be recorded. 
fufi-Se^ests/""^ -^^y full-sized member tested to destruction shall be 
paid for by the purchaser at the unit contract price, less 
its scrap value, if the test proves satisfactory. If the 
test proves the member to be unsatisfactory, the members 
represented by it will be rejected. The expense of con- 
ducting tests shall be borne by the contractor unless 
otherwise provided. 
SECTION 2. EYEBARS. 
tests ^^^ ^^^°^ When tests of full-sized bars are required the following 
conditions and requirements shall supplement the gen- 
eral provisions of section 1 above : 
siz^e of'^t™^%ars^ '^^^ number and size of the bars to be tested shall be 
" designated by the engineer before the mill order is placed. 
The number shall not exceed 5 per cent of the whole 
number of bars ordered, with a minimum of two bars on 
small orders. 
testbaJr^^^" °^ '^^^ ^^^^ ^^^'^ shall be of the same section as the bars 
to be used in the structure and of the same length if 
within the capacity of the testing machine. They shall 
be selected by the inspector from the finished bars, 
preferably after annealing. Test bars representing bars 
too long for the testing machine shall be selected fram the 
full-length bar material after the heads on one end have 
been formed and shall have the second head formed upon 
them after being cut to the greatest length which can be 
tested. 
4. Physical re- Full-sizcd tcsts of evcbars shall show a yield point of 
quirements. , , ^,^^/-^,-w^ • -i t • 
not less than 29,000 pounds per square mch, an ultimate 
strength of not less than 54,000 pounds per square inch, 
an elongation, including fracture, of not less than 10 
per cent, in a length of 20 feet measured in the body of 
the bar. The fracture shall show a uniform silky or fine 
granular structure throughout. 
5. Failure to If a bar fails to fulfill the specified requirements, two 
ments. '^^^"^'^^" additional bars of the same size and from the same melt 
shall be tested. If the failure of the first bar tested is on 
account of the character of the fracture only, the bars 
represented by the test may be reannealed before the 
additional bars are tested. 
If two of the three test bars fail to give satisfactory 
results, the bars of that size and melt shall be rejected. 
In general, test bars shall be so selected that every 
melt of material entering into the various sizes of bars 
shall be represented by at least one test. 
A failure in the head of a bar shall not be cause for 
rejection if the other requirements are fulfilled. 
