Simplified formula of hydrodynamic pressure on circular bridge piers in the time domain

The hydrodynamic pressure expression based on radiation theory is very complicated and temporal convolution in the time domain that lead to their values difficult to be calculated. The Morison equation is a semi-empirical formula and its inertia coefficient and drag coefficient are difficult to be determined accurately. Therefore, the simplified formula based on radiation theory which is concise, accurate and global decoupling in the time domain is presented by introducing three dimensionless parameters including frequency ratio, wide depth ratio and relative height of bridge pier. By analyzing the analytical formula of hydrodynamic pressure detailed, the hydrodynamic pressure formula in the frequency domain is simplified by segmenting. The simplified formula which is global decoupling in the time domain can be expressed in the form of added mass in low frequency vibration and can be expressed in the form of added mass and added damping in high frequency vibration. The calculation results show that the simplified method is in good agreement with the analytical formula. Compared with the Morison equation whose coefficients need to be selected by experience, the coefficients of the simplified formula are only related to the relative size of bridge piers. (C) 2014 Elsevier Ltd. All rights reserved.