DISPLACEMENT CALCULATION METHOD OF FLOATING ROOF IN FLOATING ROOF TANK

摘要

PURPOSE:To easily measure vertical displacement at the periphery of a floating roof by determining angular displacement of the floating roof on which a plurality of sensors for angular velocity or angular acceleration are equipped to integrate with time the detected signals from them. CONSTITUTION:Detected signals of a sensor 5, mounted on the center of a floating roof 4 and also sensors 52-54 mounted at every 45-degree on the periphery of the floating roof 4 are recorded once in a data recorder to analyse earthquake data taken out after an earthquake occurs. For the analyses, first, angular velocity (angular acceleration) detected by sensors 51-54 is once (or twice) integrated with time to calculate angular displacement. Next, a vertical displacement Y0=gamma/sintheta1 (gamma: radius of the floating roof 4) of the periphery of the floating roof in 0 degree direction is calculated from an angulardisplacement theta1 of the sensor 51 and an angular displacement theta2 of the sensor 52. Correction coefficient C1, C2 is previously calculated to compute Y0 from a formula (1), taking consideration of a deflection of the floating roof 4. The maximum vertical displacement is calculated in the same manner from the vertical displacement Y45, Y90 calculated on the floating roof periphery in the both directions of 45-degree and 90-degree.