Load bearing material

Abstract

There is provided a load bearing material with a high energy-absorbing effect at the time of deformation. A metallic external tube 2, a plurality of internal steel tubes 3, 3 A, 3 B arranged inside the external tube 2 are arranged by positioning the plurality of internal steel tubes 3, 3 A, 3 B, and thus, the load bearing capacity is improved by the plurality of the internal steel tubes 3, 3 A, 3 B. Further, when a load is applied, the internal steel tubes deform in a flattened form to thereby enable the external tube to deform as well. As a result, no stress concentrates locally on the external tube 2, thus improving an energy-absorbing effect. Further, a filler 4 is filled between an inside 21 of the external tube 2 and outsides of the internal steel tubes, thereby enabling the plurality of the internal steel tubes 3, 3 A, 313 to be simply positioned.

1 . A load bearing material including a metallic external tube and a plurality of metallic internal tubes arranged inside said metallic external tube with said plurality of metallic internal tubes positioned therein, wherein said external and internal tubes have a circular cross-section, and when a plastic deformation, takes place due to a bending moment, the internal tubes are allowed to deform in a flattened form. 
     
     
         2 . The load bearing material according to  claim 1 , wherein said load. bearing material is provided with three or more internal tubes. 
     
     
         3 . The load bearing material according to  claim 1 , wherein a positioning means for positioning said plurality of internal tubes is a filler filled between an inner surface of said external tube and outer surfaces of said internal tubes. 
     
     
         4 . The load bearing material according to  claim 2 , wherein a positioning means for positioning said plurality of internal tubes is a filler filled between an inner surface of said external tube and outer surfaces of said internal tubes. 
     
     
         5 . The load bearing material according to  claim 1 , wherein steel tubes are employed as said external tube and said internal tubes. 
     
     
         6 . The load bearing material according to  claim 3 , wherein steel tubes are employed as said external tube and said. internal tubes. 
     
     
         7 . The load bearing material according to  claim 1 , wherein said internal tubes are thinner than said external tube in tube wall thickness. 
     
     
         8 . The load bearing material according to  claim 3 , wherein said internal tubes are thinner than said external tube in tube wall thickness. 
     
     
         9 . The load bearing material according to  claim 3 , wherein a cement-based filler is employed as said filler. 
     
     
         10 . The load bearing material according to  claim 1 , wherein the outer surfaces of said internal tubes are arranged close to one another. 
     
     
         11 . The load bearing material according to  claim 3 , wherein the outer surfaces of said internal tubes are arranged close to one another. 
     
     
         12 . The load bearing material according to  claim 10 , wherein the outer surface of each internal tube is positioned close to other internal tubes at two or more places. 
     
     
         13 . The load bearing material according to  claim 10 , wherein said plurality of the internal tubes are arranged in a manner that the outer surfaces thereof are positioned close to one another to thereby define regions surrounded by some of said internal tubes, while other internal tubes are arranged inside said regions. 
     
     
         14 . The load bearing material according to  claim 12 , wherein the outer surfaces of said internal tubes are positioned close to those of other internal tubes at six or more places. 
     
     
         15 . The load bearing material according to  claim 12 , wherein two or more of said internal tubes arc arranged substantially in parallel with a centerline of a cross section of said external tube inside said external tube. 
     
     
         16 . The load bearing material according to  claim 15 , wherein three or more of said internal tubes are arranged substantially in parallel with the centerline of the cross section of said external tube.