杭州湾大桥南岸超长施工栈桥设计中风、浪、流荷载的确定

Determination of Design Loads of Wind,Wave and Flow for the Construction Trestle of Hangzhou Bay Bridge

在充分了解当地水文气候条件、综合比选各种理论与实用方法、参考已有工程经验的基础上,确定了杭州湾跨海大桥南岸超长施工栈桥设计所采用的风、浪、流荷载的计算方法。研究的主要结论:(1)为了实现安全与经济的统一,允许结构在5年、10年和20年重现期所对应的风、浪、流荷载下出现不同程度的塑性;(2)《铁规》、《港规》、《桥规》的风荷载公式的计算结果依次增大,《桥规》更适合栈桥设计;(3)与高精度方法相比,采用Airy波浪运动理论在杭州湾地区计算所得的加速度误差在5%以内;(4)对于小直径桩的波浪力,可以采用半理论半经验公式———Morrison来计算,这一公式最大的优点在于资料丰富、应用广泛;(5)与《铁规》、《桥规》相比,《港规》的潮流力计算公式更贴合海洋环境。

The calculation methods to determine the wind load, wave load and flow load which are used in the design of the trestle construction lying on the southern shore of Hangzhou Bay are ascertained on the basis of being familiar with the local hydrological and weather conditions, the synthetical comparison among several theoretical methods and practical method, and the reference of the exist similar projects＇experience. The main conclusions of the research include： （ 1 ） In order to consider both safety and economy, the trestle is allowed to go into different plastic state level under different wind, wave and steam load corresponding to 5 years, 10 years or 20years return period separately; （2） The results of the wind load formula in the Railway Specification, the Harbor Specification and the Bridge Specification are increasing in order, which means the bridge specification is more conservative and suitable for the trestle design. （3） the difference between the acceleration calculated by the Airy Theory and the highly accuracy method is with in 5 % for Hangzhou Bay. （4） The Morrison Formula, a semi-theoretical and semi-empirical formula can be used to calculate wave load of small diameter pile; （5） Compared with the Railway Specification and the Bridge Specification, the Harbor Specification is more suitable to calculate the flow load for offshore environment.