STRENGTH TESTS OP STRUCTURAL TIMBERS. H 



and fiber stress at the elastic limit was considerably less in the treated 

 material (35 and 36 per cent, respectively), and the stiffness was 

 slightly less. 



Table 1 gives the average values of the strength functions shown in 

 the diagrams, together with the highest and lowest values and some 

 additional data. 



SMALL PIECES CUT PROM STRINGERS. 



Table 2 gives the average strength and stiffness of the small pieces 

 cut from the main beams for both treated and natural material of the 

 three species under test. The average values of the small pieces cut 

 from the outside portions of the main beams and the average values 

 of the small pieces cut from the interior portions are also given. No 

 moisture determinations were made on the small pieces cut from the 

 treated longleaf and loblolly pine timbers. The determinations for 

 moisture in various parts of the cross sections of the treated timbers 

 of these two species indicate that in general they contained slightly 

 more moisture than the natural pieces. The treated sticks are in 

 general weaker than the natural sticks, but the difference is slight 

 except for partially air-dry loblolly pine. Part of the apparent loss 

 in strength of the treated material may be ascribed to its higher 

 moisture content. 



In the Douglas fir treated by the boiling process and tested green, 

 the average for the outside sticks shows a decrease in strength over 

 the natural, with but little difference in stiffness. As compared with 

 the natural sticks the treated sticks cut from the interior of the main 

 beams showed a more marked drop in strength and stiffness. The 

 air-dry material in all cases showed a decided decrease in the strength 

 of the treated sticks. The decrease in stiffness was less marked. 

 Part of this decrease may be accounted for by the higher moisture 

 content of the treated pieces. 



