Example 2 for Lamda Coefficient used in Story Drift Determination

The relative floor displacement report of the structure, whose earthquake parameters are given as the local ground class ZD and in the screenshot below, will be checked manually and then compared with the program report.

Typical plan view of the building:

Open

Earthquake parameters

Open

Calculation of Ta and Tb values

Modal participation multipliers of + - 5% eccentricity loadings read from the dynamic analysis report

Active directions are marked with a red and blue line.

Modal E1

Modal E2

Modal E3

Modal E4

Selected periods

Tx = 0.93337 s
Ty = 0.73874 s.

Lamda Account

X direction DD2

Tx=0.93337 > Tb=0.483

SAE (t) = SD1 / T = 0.705 / 0.755 = 0.93337

X direction DD3

Tx=0.93337> Tb=0.397

SAE (T) = 0,277 / 0.93337 = 0,297

Lamda = Sae (t) _DD3 / Sae (t) _DD = 0.297 / 0.397

Lamdax = 0.392 (visible in program = 0.3928)

Y direction DD2

Ty=0.73874>tb=0.483

SAE (t) = SD1 / T = 0.705 / 0.954 = 0.7384

Y direction DD3

Ty=0.73874>tb=0.397

SAE (t) = SD1 / T = 0.277 / 0.375 = 0.7384

Lamda = Sae (t) _DD3 / Sae (t) _DD2 = 0.397 / 0.954

Lamday = 0.393 (visible in program = 0.3928)

Relative floor shift upper limit control

The largest relative floor offset = 0.393 * 55.46 / 2800 ^(mm) = 0.0078 mm <0.008 provided