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Thornton Tomasetti 24 of 234 <br />SHEAR DCR L3.L4 COLUMNS <br />ALONG GL 13 (WEST) <br />72YR (50%/50YR) GROUND MOTIONS <br />DAMPERS ACTING AT DESIGN PARAMETERS <br />SHEAR DCR DISTRIBUTION <br />90 <br />·11 COLUMNS @ L3-L4 ALONG GL 13* <br />4 TIME HISTORIES * <br />4 DIRECTIONAL COMBINATIONS PER TH * <br />MAX REPORTED FOR EACH COMBINATION (SMALLER COMP) <br />=11*4*4=176 TOTAL ENTRIES TO EVALUATE SHEAR DCR <br />80 <br />70 <br />60 <br />Mean DCR 0.71 <br />Median DCR 0.70 <br />Total Entries 176 <br />% DCR>1.0 2.27% <br />NOTES: <br />50 1-THE ASCE41-13 EQUATION FOR SHEAR CAPACITY DEPENDS ON THE LEVEL OF AXIAL <br />COMPRESSION Nu. AND MOMENT DEMAND. M RATHER THAN PRESENT Nu AND M FOR EACH <br />TIME STEP, ETABS REPORTS THE MAX AND MIN VALUES BY COLUMN BY TIME HISTORY <br />40 USING THE LOWEST AXIAL COMPRESSION OR LARGEST NET TENSION IN A COLUMN WHEN <br />DETERMINING ITS SHEAR CAPACITY IS A WORST-CASE, OFTEN CONSERVATIVE. APPROACH <br />TO SHEAR DCRs. <br />30 <br />2 - FOR EXAMPLE, COLUMN C245 REPORTS All DCR USING THE ENVELOPING APPROACH IF <br />INSTEAD SHEAR DCR IS TRACKED AT EACH TIME STEP FOR THE SAME COLUMN AND GROUND <br />20 MOTION. THE MAXIMUM DCR IS 0.71 BECAUSE THE TIME STEP WITH WORST-CASE AXIAL <br />FORCE IS DIFFERENT FROM THE TIME STEP WITH HIGHEST SHEAR DEMAND <br />3-ALL COLUMNS ON AN ELEVATION ACT TO RESIST STORY SHEAR. COLUMNS NOT AT <br />CORNERS HAVE SPARE CAPACITY SO TOTAL SHEAR RESISTANCE >> TOTAL SHEAR DEMAND <br /> SEE NOTE 2 ON EACH ELEVATION <br />0 <br />10.6,0.7]10.7.0.8]CO.8,0.91 (0.9,1.01 (1.0,11](1 1,1.2] <br />DER SEE NOTE-1 111=kE,=k A, Ed <br />X <br />IX **E4 1+ <br />N. <br />6 4* A,0.8 Ae <br />(lb/in.2 units)