DESIGN,. FABRICATION AND PERFORMANCE. OF OSCILLATORY SHEAR BOX

Abstract

Fast progressing science and technology have enabled mankind to errect larger and taller structures. With that their safe functionina has become an urgent necessity, creating many difficult problems. One such in active seismic zones is to safe- guard the foundations of structures, or the earth structures against earthquake forces.A thorough knowledge of strength of soil under such dynamic loads is essential in solving the problem. Seed and others have recently attempted to study the strength characteristics of soil subjected to simulated earht-quake stresses. Their apparatus is in the stage of development and utilizes electrically controlled pneumatic loading systems. This makes the apparatus quite complicated and hence not easily adoptable extensively for such studies. An attempt is made here to design and fabricate a setup which is simple, easy to work, robust, lessliable to go out of order, and cheap. It utilizes a modified F~oscoe's simple shear box, The oscillatory shear forces are applied through weights hung on either si.ae of the box, which are alternatively lifted by a pair of cams with their accentricities at 1800 phase differe- nce, and driven by an electric motor. Loads and displacements are measured and recorded with suitable equipment. Its performance was satisfactory. However, some more improvements are suggested. There is much scope for further developments-.