146 



REPORT 1869. 



Appendix I. 



In addition, to the foregoing experiments, it was considered desirable to 

 have a steel beam made of the usual form, in order to ascertain the compa- 

 rative merits of steel and wrought-iron girders. Por this purpose two 

 beams were constructed, of that quality of steel best suited to ensure dura- 

 bility and safety. A much harder description of steel (40 tons to the square 

 inch) might have been chosen ; but that was not wanted, for the object sought 

 was ductHity and moderate strength in its powers to resist impact. The fol- 

 lowing experiments will show the results. 



Experiment on a Steel Girder from the Barrow Hsematite Steel Company. 

 Length between the supports 13-9 feet. Sectional area 2-31 inches. 



No. 



of 



Expt. 



1 

 2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



19 



20 



Weight laid 

 on girder. 



lbs. 

 866 



3106 



5346 



7586 



9826 



12068 



14308 



16550 



18790 



21020 



23260 



26880 



29120 



33600 



35840 



36060 



38080 



39200 



40320 



40544 



tons. 



0-386 



1-386 



2-386 



3-386 



4-386 



5-386 



6-386 



7-386 



8-386 



9-386 



10-386 



12-000 



13-000 



15-000 



16-000 



16-098 



17-000 



17-500 



18-000 



18-100 



Deflection, 

 in 



inches. 



•056 

 -108 

 •147 

 •184 

 •201 

 -260 

 -304 

 •322 

 •339 

 -372 

 •423 

 •480 

 •545 

 •626 

 •802 

 •965 

 1^430 

 1^872 



Eemarks. 



Weight of slings &e. 



•I 



r ix2| 



iX2^ 



T 



00OOO0O0OOQO 



O O O 





O 

 _i 



Broke by tension through the angle-iron of the 

 bottom flange, as above. 



