VIBRATION TESTS OF A HIGH RISE BRIDGE PIER USING ROCKET PROPULSION METHOD

TWO METHODS OF VIBRATION TESTS WERE USED ON A HIGH RISE PIER OF STEEL FRAMED REINFORCED CONCRETE AT THE SOKOZAWA BRIDGE SITE. FORCED VIBRATION OF STRUCTURE OR STRUCTURAL ELEMENTS IS CAUSED BY A MECHANICAL EXCITOR WITH ROTATING ECCENTRIC MASS, A LARGE MASS PENDULUM OF ADJUSTABLE NATURAL PERIOD, OR ARTIFICIAL EXPLOSION OF SMALL MAGNITUDE. DAMPED FREE VIBRATION OF STRUCTURE IS CAUSED BY A SUDDEN RELEASE OF STATIC DISPLACEMENT BY PULLING WIRE OR ROCKET PROPULSION. THE CALCULATED VALUES AND TEST RESULTS ARE COMPARED. THE CONCLUSIONS FROM THE VIBRATION TESTS ARE: (1) THE OBTAINED VALUES OF NATURAL FREQUENCY WELL AGREE WITH THE CALCULATED ONES BASED ON THE ASSUMPTION THAT THE PIER IS A CANTILEVER FIXED AT THE BOTTOM; (2) THE OBTAINED VALUES OF DAMPING CONSTANT (RATIO TO THE CRITICAL DAMPING) ARE 0.006 TO 0.01; THEY ARE CONSIDERABLY SMALLER THAN THOSE USUALLY EXPECTED WITH THE STEEL FRAME REINFORCED CONCRETE; AND (3) IT HAS BEEN VERIFIED THAT ROCKET PROPULSION METHOD IS USEFUL IN CAUSING DAMPED FREE VIBRATION OF STRUCTURES AND THUS IN OBTAINING THE DYNAMIC CHARACTERISTICS OF STRUCTURES.

• Supplemental Notes:
  • pp 44-50, 6 FIG, 4 TAB
• Authors:
  • Okubo, T
  • IWASAKI, T
• Publication Date: 1969

Media Info

• Serial:
  • Japan Road Association Annual Report of Roads
  • Publisher: Japan Road Association

Subject/Index Terms

• TRT Terms: Bridge piers; Calculation; Damping (Physics); Dynamics; Reinforced concrete; Steel; Structures; Vibration
• Uncontrolled Terms: Computation; Dynamic characteristics; Rockets
• Old TRIS Terms: Test results
• Subject Areas: Bridges and other structures; Construction; Highways;

Filing Info

• Accession Number: 00209342
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 28 1970 12:00AM