EOCKY MOUNTAIN MINE TIMBERS. 7 



Table 4. — Summary of bending tests on round beams, 16 feet long (span, 15 feet; third- 

 point loading). 



GREEN (WATER SOAKED). 



Species, size, number of 



Moisture. 



Rings 

 per 

 inch. 



Diameter. 



Modulus 



of 

 rupture. 



Fiber 



stress at 



elastic 



limit. 



Stiffness 

 factor 



(1) 



Work 

 to maxi- 



tests. 



Top. 



Butt. 



mum 

 load. 



Lodgepole pine, cut from 

 live timber: 

 8-incb butt, 10 tests— 



Per cent. 

 77.3 

 99.4 

 62.1 



90.2 

 118.2 

 73.4 



91.8 

 99.6 

 78.3 



38.1 

 45.2 

 35.0 



40.1 

 47.7 

 29.8 



37.2 

 41.7 

 27.8 



32 

 37 



28 



27 

 32 

 21 



23 

 24 

 18 



44 

 52 

 34 



40 

 48 

 35 



28 

 34 

 24 



Inches. 

 6.77 

 7.32 

 6.29 



8.26 

 9.23 

 7.24 



9.82 

 10.82 

 9.23 



7.00 

 7.08 

 6.92 



8.21 

 9.23 

 7.56 



10.00 

 10.98 

 9.31 



Inches. 

 8.20 

 8.75 



7.76 



9.97 

 10.74 

 9.39 



11.62 

 12. 41 

 10.98 



8.50 

 9.06 

 7.80 



10.24 

 11.14 

 9.71 



12.47 

 12.97 

 11.77 



Lbs. per 



sq. in. 



5,348 



6,210 



4,860 



5,233 

 6,230 

 4,510 



5,095 

 6,2 7 

 4,230 



5,448 

 6,580 

 3,570 



4,940 

 6,500 

 3,870 



4,430 

 5,680 

 3,820 



Lbs. per 



sq. in. 



3,120 



4,200 



2,425 



3,008 

 3,905 

 2,038 



2,987 

 3,780 

 2,298 



2,905 

 3,690 

 2,210 



2,950 

 4,180 

 1,592 



2,320 

 2,960 



1,828 



10.99 

 13.42 

 9.26 



10.32 

 11.73 



7.48 



10.23 

 13.70 

 8.16 



10.38 

 13.25 

 8.00 



8.84 

 10.97 

 7.09 



7.71 

 9.71 

 5.18 



Inch lbs. 



per cu. in. 



4.7 





6.6 





2.6 



10-inch butt, 10 tests— 



5.5 





7.8 





3.2 



12-inch butt, 10 tests- 



5.2 





7.0 



Minimum 



2.0 



Lodgepole pine, cut from 

 timber after standing 

 dead for 30 years: 

 8-inch butt, 5 tests- 

 Average 



5.3 





7.6 



Minimum 



2.3 



10-inch butt, 5 tests — 



3.4 





5.4 





1.6 



12-inch butt, 5 tests — 



4.3 





8.2 





2.0 







AIR SEASONED. 



Lodgepole pine, cut from 

 live timber: 



8-inch butt, 5 tests — 



Average 



Maximum 



Minimum 



10-inch butt, 5 tests- 

 Average 



Maximum 



Minimum 



12-inch butt, 5 tests — 



Average 



Maximum 



Minimum 



Lodgepole pine, cut from 

 timber after standing 

 dead for 30 years: 



8-inch butt, 9 tests- 

 Average 



Maximum 



Minimum 



10-inch butt, 10 tests- 

 Average 



Maximum 



Minimum 



12-inch butt, 11 tests- 

 Average 



Maximum 



Minimum 



16.8 

 19.9 

 15-2 



32 

 34 

 29 



6.99 

 7.64 

 6.37 



8.04 

 8.36 

 7.64 



7,748 

 9,310 

 7,160 



5,018 

 5,290 

 4,640 



14.05 

 16.80 

 12.43 



17.1 

 18.3 

 14.6 



25 

 27 

 23 



8.09 

 8.59 

 7.08 



9.77 

 10.03 

 9.55 



6,948 

 9,060 

 4,480 



4,816 

 5,940 

 3,190 



13.33 

 18.75 

 10.31 



19.3 

 21.8 

 17.7 



22 

 23 

 21 



9.73 

 9.95 

 9.55 



11.51 

 11.81 

 11.14 



5,409 

 6,350 

 3,745 



3,741 

 4,340 

 2,875 



9.57 

 11.62 

 6.85 



13.7 

 14.6 

 11.5 



40 

 51 

 34 



6.98 

 7.64 

 6.45 



8.39 



8.91 



• 7.48 



5,625 



7,780 

 3,843 



4,649 

 6,720 

 3,195 



10.92 

 12.51 

 9.58 



12.9 



14.4 

 12.1 



34 

 42 

 24 



8.27 

 8.91 

 7.64 



10.11 

 10.66 

 9.31 



5,166 

 8,970 

 2,690 



4,489 

 6,400 

 2,585 



10.54 

 13.53 

 8.06 



13.8 

 16.6 

 12.0 



31 



37 

 24 



9.16 

 11.14 

 9.07 



12.15 

 12.49 

 11.46 



4,720 

 7,310 

 2,060 



3,925 

 5,960 

 1,343 



9.84 

 12.29 

 8.12 



3.8 

 4.9 

 2.7 



3.1 

 4.0 

 1.5 



2.3 

 3.0 

 1.2 



2.1 

 5.6 



2.3 



4.2 



.5 



1.7 



3.8 



.4 



The average results do not show a consistent difference in the 

 relative strength of the various species tested. Figures 1 and 2 show 

 that, with the exception of the green props and caps of Douglas fir 

 and the dry props of lodgepole pine (Shipment B), there is not a 

 very large difference in the strength of the various shipments. Ty 



