Comparison of Field Measurement and Numerical Simulation of the T-Shaped Barge Motions During the Topside Floatover Installation

Abstract

This paper presents the comparison of field measurement and numerical simulations of the barge motions in the successful floatover installation of one mega topside in Bohai Bay, China. The motion measurements of the T-shaped floatover barge HYSY228 and the environmental field measurements were conducted to guide the entire floatover operation. The motion monitoring system can provide up to centimeter-level accuracy to monitor the six-degree-of-freedom barge motions. The environmental monitoring systems include one buoy system measuring the wave height, period and direction, an Acoustic Doppler Current Profilers (ADCP) for the profile current speed and direction, an anemometer, and a tidal gauge. Numerical simulation is carried out for the barge motions in the standby stage of floatover installation in mooring condition. The motions of the barge and mooring force responses are obtained by the commercial code SESAM using the measured environmental data. Two different methods, Newman’s approximation and Second-order Transfer Function (QTF), are used to predict the second order wave force. The wave component (high frequency) and the second order component (low frequency) are discussed. Statistical results are compared with those from the field measurement. Fair well agreement is achieved.