A FATIGUE TEST ON T-SHAPED CONCRETE BEAMS REINFORCED WITH DEFORMED BARS

THIS PAPER REPORTS A STUDY ON THE FATIGUE CHARACTERISTICS OF CONCRETE BEAMS REINFORCED WITH DEFORMED BARS. THE MAXIMUM RANGE OF LOAD WAS SET TO 2200 KG./CM.SQUARED IN BAR STRESS TO EXAMINE THE CHANGE OF BEAMS NEAR ALLOWABLE STRESS AND IT WAS SUBSEQUENTLY RAISED BY 400 KG./CM. SQUARED UNTIL FAILURE. THE MINIMUM RANGE WAS KEPT AT 560 KG./CM. SQUARED IN BAR STRESS. FROM THE EXPERIMENTAL RESULTS THE FOLLOWING CONCLUSIONS ARE REPORTED: (1) UNDER THE ABOVE MENTIONED CONDITIONS, ALL THE BEAMS REINFORCED WITH DEFORMED BARS FAILED DUE TO THE FATIGUE OF STEEL AND THOSE WITH PLAIN BARS DID NOT FAIL UNTIL ALMOST THE YIELD POINT. THE FATIGUE STRENGTH OF DEFORMED BARS SEEMED TO BE MUCH INFLUENCED BY THE DEFORMATIONS. (2) AS TO THE CRACK WIDTH, LITTLE DISTINCTION WAS RECOGNIZED AMONG DEFORMED BARS AND THEY KEPT ALMOST CONSTANT EXCEPT THE GROWTH OF 0 TO 20 PERCENTS TILL 10 DEGREE CYCLES. WHILE A BEAM WITH 4-13 MM. PLAIN BAR WAS THE SAME AS THE DEFORMED BARS, ONE WITH 1-25 MM. PLAIN BAR WAS 1.5 TIMES AS LARGE AS THE DEFORMED BARS AND THE RATIO GREW TO 1.8 TIMES AS THE LOAD REPEATS, (3) THE COMPRESSIVE STRAIN AT THE UPPER EXTREME FIBRE, WHERE THE STRESS PULSATED BETWEEN 68 AND 11 KG./CM. SQUARED, WAS ALMOST CONSTANT. THE REMAINING COMPRESSIVE STRAIN INCREASED BY 0 TO -16. 8 X 100,000 AND THE ELASTIC STRAIN CHANGED BY 4.8 TO -2.7 X 100,000 IN 1,000,000 CYCLES, AND (4) THE ELASTIC DEFLECTION AT THE CENTRE OF THE SPAN INCREASED BY 5 TO 20 PERCENT TILL 100,000 CYCLES AND THEY KEPT CONSTANT THEREAFTER. /CRRI/

• Supplemental Notes:
  • No 122, pp 43-50
• Corporate Authors:

  Japan Society of Civil Engineers

  1-chome, Yotsuya, Shinjuku-ku
  Tokyo,   Japan  160-0004
• Authors:
  • Nakayama, N
• Publication Date: 1965-10

Subject/Index Terms

• TRT Terms: Beams; Compressive strength; Concrete; Deflection; Deformation; Deformed bars; Elastic analysis; Fatigue tests; Load tests; Reinforced concrete; Steel; Strain (Mechanics); T beams
• Uncontrolled Terms: Concrete beams
• Old TRIS Terms: Elastic analysis (Structural); Strains
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208475
• Record Type: Publication
• Source Agency: Central Road Research Institute
• Files: TRIS
• Created Date: Jul 1 1994 12:00AM