END-MOVEMENT STUDIES OF VARIOUS TYPES OF HIGHWAY BRIDGES

STUDIES ARE UNDER WAY TO MEASURE AND RECORD THE END MOVEMENTS OF VARIOUS TYPES OF BRIDGES IN CENTRAL VIRGINIA. AN INSTRUMENT IS DESCRIBED WHICH WAS DEVELOPED TO AUTOMATICALLY MEASURE AND RECORD BOTH MOVEMENT AT THE TOP AND BOTTOM OF THE BRIDGE GIRDER AND AMBIENT AIR TEMPERATURE. TWO DIAL GAGES WERE MOUNTED ON LEVERS BETWEEN THE ABUTMENT AND THE GIRDERS SO THAT THE UPPER AND LOWER BEAM MOVEMENTS WERE DETECTED AT THE POSITION OF A SMALL GAGE BOX MOUNTED ON THE ABUTMENT AT THE MOVABLE END OF THE BRIDGE. A BULB THERMOMETER, CLOCK, AND TIMER WERE MOUNTED IN THE GAGE BOX. A MOVIE CAMERA TOOK PICTURES OF THE VARIOUS DIAL AND THERMOMETER READINGS EITHER CONTINUOUSLY OR ONCE AN HOUR, AS IN NORMAL USE. THE WHOLE UNIT WAS MOUNTED IN A SELF- CONTAINED BOX AND WAS BATTERY OPERATED. FOUR BRIDGES, ALL OF DIFFERENT LENGTHS AND TYPES, WERE EACH STUDIED FOR APPROXIMATELY ONE YEAR. THEY WERE BRIDGES OF THE FOLLOWING TYPES: (1) A COMPOSITE BRIDGE WITH STEEL BEAMS AND CONCRETE DECK, (2) A COMPOSITE BRIDGE OF PRESTRESSED CONCRETE BEAMS AND CONCRETE DECK, (3) A BRIDGE OF MONOLITHIC REINFORCED CONCRETE, AND (4) A NON-COMPOSITE BRIDGE WITH STEEL BEAMS AND CONCRETE DECK. A GENERAL BUT IMPRECISE RELATIONSHIP WAS FOUND BETWEEN AIR TEMPERATURE AND MOVEMENT, WHICH WAS SUBJECT TO A LAG TIME FOR THE MOVEMENT RANGING FROM ONE TO SEVEN HOURS. IT WAS OBSERVED THAT MOVEMENTS AT THE TOP AND BOTTOM OF THE GIRDER WERE CONSIDERABLY DIFFERENT, RESULTING IN AN END ROTATION OF THE GIRDER. AS A GUIDE FOR DESIGN, IT SEEMS REASONABLE TO ASSUME THAT END MOVEMENTS EQUAL TO ABOUT TWICE THE THEORETICAL VALUES CAN OCCUR. THEORETICAL VALUES ARE ASSUMED TO BE THE MATHEMATICAL PRODUCT OF COEFFICIENT OF EXPANSION OF THE MATERIAL, THE MOVING LENGTH OF THE STRUCTURE, AND THE CHANGE IN AMBIENT TEMPERATURE. TEMPERATURE APPEARS TO BE THE MAJOR PARAMETER AFFECTING LENGTH CHANGES, ALTHOUGH OTHERS THAT PLAY A ROLE ARE ACTUAL TEMPERATURES INSIDE THE STRUCTURE, SOLAR RADIATION, VOLUMETRIC CHANGES CAUSED BY MOISTURE AND CHEMICAL ACTION, CREEP AND SHRINKAGE, BEARING RESTRAINTS, PIER AND ABUTMENT MOVEMENTS, AND LOADING CHANGES AND VIBRATION.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrr/1969/295/295-001.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Bridge Design. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Zuk, William
• Publication Date: 1969

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: pp 1-4
• Monograph Title: Bridges
• Serial:
  • Highway Research Record
  • Issue Number: 295
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Beams; Bridge abutments; Bridge decks; Composite materials; Concrete; Creep; Highway bridges; Length; Measuring instruments; Monoliths; Motion pictures; Prestressed concrete; Prestressing; Recording; Reinforced concrete bridges; Shrinkage; Temperature; Temperature measurement; Thermal expansion; Volume changes
• Uncontrolled Terms: Change
• Old TRIS Terms: End movements
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00209145
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Mar 9 1970 12:00AM