Comparative Study Of Chinese And Overseas Different Methods For Channel Width Calculation Under Strong Tidal Current

As China’s economy continues to develop, international logistics circulation is becoming increasingly frequent, which has contributed to the booming development of shipping industry. As an important node for domestic and foreign trade of cargos, seaports has led to significant improvement for coastal economy. Meanwhile, sea channels, as an essential component of a seaport, directly affects its navigable capacity, and thus become some of the key factors for local economic development. As a result, a scientifically determined channel width will help to improve the efficiency of sea port operations, ensure ship navigation safety and sea port security, and thus enhance the coastal economic development.In recent years, with the rapid development in sea port constructions and large-scale vessels, site selections for new sea ports started to consider deep water areas, where strong cross flow increases the difficulty of vessel-handling and reduces navigation safety, which add to more difficulties in previous designs and constructions. Therefore, higher requirements has been put forward concerning the channel width. Despite the fact, in order to save dredging costs, and meet the demand of large-scale vessels, many domestic and foreign sea port shave selected locations under the influence of strong tidal current(with cross flow velocity greater than1.Om/s).In China’s current specifications, Overall Design Code for Sea Ports (JTS165-2013), the values of wind and flow pressure angle are not specified, in the case of cross-flow velocity exceeding1.0m/s. So to some extent, this code is not suitable for the design of navigable waterway width in strong tidal current occasions.This paper investigates Overall Design Code for Sea Ports (JTS165-2013) of China, Technical Standards and Commentaries for Port and Harbour Facilities in Japan and a Guide for Design of PIANC of the United States. In this paper, Bulk carriers, Container ships, Oil tankers and Ro-Ro ships are studied; cross-flow, vessel velocity and ship tonnage are selected as the main influencing factors, and channel width values corresponding to different National Design Codes are thus calculated. Using Origin, a comparative analysis based on the channel width values is conducted. Consequently, the differences in calculation methods and navigation conditions are concluded, factors leading to the differences are analyzed, and recommendations concerning channel width calculation under strong tidal currents are introduced.This paper also analyzes the impact of a variety of factors(e. g. cross-flow, vessel velocity, ship tonnage, etc.) upon National Codes regarding channel width design. After the sequencing of the designed values, the influence of each affecting factor upon various design methods is investigated. In order to promote the rapid, healthy and sustainable development of China’s shipping industry, this paper gives recommendations for the improvement of China’s design code in terms of channel width design, provides scientific basis for relevant authorities, and serves as a support for future decision-making for sea port construction in strong tidal current areas.