Abstract
With the continued development of transportation, the risk of ship-bridge collision has been rising persistently. Meanwhile, a great mass of old bridges which were built decades ago can’t meet the anti-collision requirement nowadays. Many countries and regions noticed that problem and have been taking various measures to protect those bridges and provide a better navigable environment. For tabling reasonable protective proposals for each bridge, the first step is assessing the safety based on the design, current representative vessels, and so on. Hence, it is necessary to propose a simple, fast, and accurate method that can be widely used in practical engineering. Kinds of simplified formulae, e.g. AASHTO and IABSE, are used to calculate the ship collision force, however, the results are static forces that have errors. Consequently, the PRC Ministry of Transport (MOT) published the Specifications for Collision Design of Highway Bridges in 2020 which calculates the collision force as a simplified dynamic history. This paper compares the simplified dynamic histories with the numerical results obtained from LS-DYNA by using several ship models in different cases. Subsequently, a method of safety assessment for bridges against ship collisions based on Midas Civil is designed. The applicability and accuracy of this new specification in force calculations and safety assessments are discussed based on acceptable errors. The comparison indicates that for 500∼10000DWT ships, the simplified formula can calculate the momentum precisely with a certain error on the peak force and total time though. To expand the scope of the application, the specification still has relatively large errors and limitations in some cases.
