THE STUDY OF ’DETERMINATION OF PARAMETERS FOR THE DESIGN MODEL FOR TIMBER I-JOISTS IN FIRE’ SHOW THE METHODOLOGY FOR SEARCHING COEFFICIENTS ABOUT HOW TO CONSIDER AND DEFINE THE EFFECT OF FIRE ON TIMBER STRUCTURES. THIS STUDY IS A PART OF THE THESIS MADE IN TALTECH UNIVERSITY BY KATRIN NELE MAGER AND WITH THE SUPERVISION OF THE PROFESSOR ALAR JUST. IN THIS STUDY CONSISTS IN THE RESEARCH OF THE COEFFICIENT K3,1 FORMULA, COEFFICIENT THAT DEFINES THE CHARRING ALONG THE FIRE-EXPOSED SIDE TAKING INTO ACCOUNT THE PROTECTION OFFERED BY THE INSULATION AND THE PROTECTION BOARD IN POST-PROTECTION PHASE. INITIALLY THE SIMULATIONS ARE DONE WITH THE SAFIR PROGRAM OF SOME SPECIFIC CASES OF TIMBER STRUCTURES UNDER THE EFFECTS OF FIRE, FROM WHERE MANY DATA ARE OBTAINED. THEN THE ITERATIONS ARE MADE WITH AN ALGORITHM IN THE MATLAB PROGRAM WHERE A LOT OF RESULTS OF ALL IMPORTANT AND POSSIBLE SITUATIONS ARE OBTAINED. IN THIS PART IS WANTED TO COVER ALL THE POSSIBILITIES TO GETTING A PATRON ABOUT HOW THE FIRE AFFECTS AN I-JOIST IN CASE OF FIRE IN THE BUILDING. ONCE IT HAS THE TRANSCENDENTAL DATA, IT IS GATHERED THEM IN EXCEL SO CERTAIN BEHAVIOR PATTERNS CAN BE DEDUCTED. FROM THERE IT IS MISSING TO DEEPLY INVESTIGATE THE DATA TO SEEK TRENDS AND ARRIVE TO A FORMULA THAT REPRESENTS THEM ALL IN EXACTLY MANNER A MORE OR LESS. AS A FINAL RESULT THE COEFFICIENT K3.1 IS DEFINED WITH A FORMULA THAT USES VARIABLES EASIER TO OBTAIN. ON THE OTHER HAND, SOME FIRE TESTS ARE DONE IN REAL I-JOIST TO HAVE THE SAME RESULTS. THE MAIN OBJECTIVE IS TO COMPARE THOSE RESULTS TO THE FORMULA RESULTS. THEN WITH THE COMPARATIONS IT IS POSSIBLE TO MAKE AN IDEA OF HOW THE EQUATION IS FITTED TO REALITY. FINALLY THE COMPARISON GIVES SOME CONCLUSIONS CAN HELP TO UNDERSTAND BETTER HOW TIMBER EVOLVES AGAINST FIRE AND WHICH ASPECTS ARE MISSING TO IMPROVE THE BEHAVIOR OF WOOD IN CASE OF FIREOutgoin
