ANALYSIS OF BOX-TYPE STRUCTURES

A METHOD OF ANALYSIS OF BOX-GIRDER AND MULTICELLULAR BRIDGE DECKS IS PROPOSED. ALTHOUGH SIMILAR TO THE DIRECT STIFFNESS TECHNIQUE, IT INCORPORATES THE MATRIX PROGRESSION CONCEPT FOR OBTAINING THE STIFFNESS MATRICES FOR THE INDIVIDUAL PLATE ELEMENTS: RESULTS FROM EXPERIMENTS WITH TWO PERSPEX MODELS ARE SHOWN TO AGREE SATISFACTORILY WITH THEORETICAL CALCULATIONS. THE METHOD OF ANALYSIS IS SYSTEMATIC AND CONVENIENT FOR COMPUTATION. COMPUTER STORE REQUIRED FOR A MULTI-CELL BOX IS SMALL COMPARED TO OTHER NUMERICAL METHODS SINCE THE PLATES BETWEEN JUNCTIONS CAN BE CONSIDERED AS INDIVIDUAL ELEMENTS AND FURTHER SUBDIVISIONS ARE UNECESSARY. CONVERGENCE OF THE MOMENTS AND FORCE QUANTITIES IS SLOWER THAN THAT OF THE DISPLACEMENTS. HOWEVER, FOR THE EXAMPLES CITED SUMMATION OF 19 HARMONICS WAS CONSIDERED TO BE SUFFICIENT. THE GENERAL FLEXIBILITY OF THE METHOD MAKES IT POSSIBLE TO REPRESENT PRECISELY ANY LOAD CONDITION, WHETHER IT IS NORMAL OR IN-PLANE, BY USING SUITABLE FOURIER REPRESENTATION. ADDITIONAL FORCES APPLIED THROUGH PRESTRESSING CAN ALSO BE INCORPORATED IN THE LOAD VECTOR WHEN DIVIDED INTO CORRESPONDING COMPONENTS IN THE VERTICAL AND HORIZONTAL DIRECTIONS. THE PROBLEM OF INTERMEDIATE SUPPORTS CAN BE ANALYZED USING AN INFLUENCE TECHNIQUE IN WHICH THE INTERNAL REACTIONS ARE FIRST CALCULATED FROM THE CONDITIONS THAT THE RESULTANT DEFLECTIONS AT THE SUPPORTED POINTS ARE ZERO. THE FINAL SOLUTION IS THAT OF A SINGLE-SPAN STRUCTURE UNDER THE COMBINED ACTION OF THE APPLIED LOAD AND THE REACTIONS. THE ADVANTAGE OF THE METHOD IS ITS APPLICABILITY TO ELEMENTS OTHER THAN THE ISOTROPIC RECTANGULAR PLATE ELEMENTS. A SMALL CHANGE OF THE GOVERNING MATRICES CAN MAKE THE SOLUTION SUITABLE FOR ORTHOTROPIC RIGHT OR FAN-SHAPED PLATES. FURTHERMORE THE STIFFNESS MATRIX FOR A SHELL ELEMENT CAN BE OBTAINED BY USING THE SAME MATRIX PROGRESSION TECHNIQUE. THESE EXTENSIONS ARE LIKELY TO MAKE THIS METHOD SUITABLE FOR A NUMBER OF COMPLEX BRANCH PLATE PROBLEMS INCLUDING THE RIGHT OR CURVED BOX-TYPE BRIDGE DECKS. /TRRL/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 19-40
  • Serial:
    • Volume: 53

Subject/Index Terms

Filing Info

  • Accession Number: 00210069
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: May 24 1974 12:00AM