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Thornton Tomasetti 225 of 234 <br />ITEM #1 - L3-L4 COLUMN SHEARS > 1.0 <br />L3-L4 COLUMN SHEAR DCR EVALUATED BY TIME-STEP <br />Column Ground Motion DCR from Enveloped Results Max DCR by Time-Step <br />C245 72yr NR a Max 1.069 0.692 <br />C245 72yr NR b Max 1.107 0.713 <br />C246 72yr NR a Max 1.086 1.086 <br />C246 72yr NR b Max 1.092 1.092 <br />C220 72yr NR a Max 1.094 0.668 <br />C220 72yr NR b Max 1.095 0.688 <br />C223 72yr NR a Max 1.086 1.086 <br />C223 72yr NR b Max 1.092 1.092 <br />C7 72yr NR c Max 1.202 1.202 <br />67 72yr NR d Max 1.203 1.203 <br />C9 72yr NR c Max 1.039 1.038 <br />C9 72yr NR d Max 1.137 1.136 <br />C115 72yr NR c Max 1.157 0.731 <br />C115 72yr NR d Max 1.198 0.751 <br />C125 72yr NR c Max 1.220 1.220 <br />C125 72yr NR d Max 1.221 1.221 <br />C126 72yr NR c Max 1.031 0.991 <br />C126 72yr NR d Max 1.121 1.070 <br />C171 72yr NR d Max 1.072 0.787 <br />C172 72yr NR c Max 1.192 0.704 <br />C172 72yr NR d Max 1.204 0.721 <br />NOTES: <br />THE SELECT COLUMNS LISTED ABOVE ARE ONES THAT REGISTERED OVER 1.0 SHEAR DCR DUE TO ENVELOPED AXIAL AND <br />SHEAR FORCES OVER THE COURSE OF A GROUND MOTION. <br />CALCULATING THE DCRS BY TIME-STEP PROVIDES A MORE ACCURATE ASSESSMENT OF MAX UTILIZATION. <br />COLUMNS EXCEED 1.0 SHEAR DCR ONLY UNDER THE NORTHRIDGE GROUND MOTION 'PULSE' APPROXIMATELY 4 SECONDS <br />INTO THE RECORD (DCR FIGURES BY TIME-STEP ARE PROVIDED FOR EACH COLUMN ON FOLLOWING SHEETS). <br />FOR EACH ELEVATION. COLUMNS AT ONE END ARE IN COMPRESSION WHILE COLUMNS AT THE OTHER END MAY BE IN <br />TENSION DURING THE'PULSE' TIME-STEP. THE COLUMNS IN COMPRESSION BENEFIT FROM LARGER CAPACITIES AND THEIR <br />UPDATED DCRS BY TIME-STEP ARE HIGHLIGHTED IN GREEN ABOVE. 'TENSION-SIDE' COLUMN REDUCED SHEAR CAPACITY <br />OCCURS SIMULTANEOUSLY WITH THE PULSE-INDUCED SHEAR. <br />BECAUSE ALL COLUMNS ON AN ELEVATION ACT TO RESIST STORY SHEAR AND COLUMNS NOT AT THE CORNERS HAVE <br />SPARE CAPACITY. TOTAL SHEAR RESISTANCE >> TOTAL SHEAR DEMAND AT EACH ELEVATION. <br />THE ONLY ELEMENTS MODELED AS NON-LINEAR ARE THE VISCOUS DAMPERS. IN REALITY. COLUMNS YIELDING IN TENSION <br />WOULD HAVE REDUCED STIFFNESS. THE FINAL SHEET SENSITIVITY STUDY RELATED TO ADJUSTING COLUMN MOMENT OF <br />INERTIA MODIFIERS IN ETABS TO REFLECT TENSION-SIDE COLUMN SOFTENING SHOWS TENSION COLUMN DCRS<1 AND <br />OTHER COLUMN DCRS <1.