A floating tied system for an offshore airport

This paper presents a new system for a floating offshore airport. It consists of an assembly of precast boxes, each of them tied with a cable system. The (tension) cable system acts as a bracing against any lateral forces during airport operation. It also prevents the boxes from oscillating and moving during the airport construction and operation. The space inside each box can be utilized for other purposes. A top slab system consisting of precast and cast in situ concrete slabs will form the platform of the airport. Finally, a proposed method of construction is also presented. The new system offers an easier construction method and allows future airport extension and even relocation.     

海洋工程施工围堰用海方式界定问题分析与探讨

文章从工程与工作实践出发,对填海造地工程、跨海桥梁、水利工程等海洋工程施工围堰用海方式界定问题进行了分析与探讨。针对施工围堰与项目申请用海方式不一致的情况,提出了分阶段确权的解决方法。期望为海域管理和海域使用动态监视监测工作提供有益参考。     

导管架平台健康监测中的信号处理技术

振动信号处理技术能够提取反映结构健康的特征信息,在导管架平台健康监测中发挥了重要作用。为了给导管架平台健康监测与振动特征提取的发展提供借鉴和指导,文中对导管架平台特征提取中常用的信号处理方法:傅里叶变换、小波变换和希尔伯特-黄(Hilbert-Huang)变换进行了综述,系统总结了它们的基本理论、适用范围、优缺点以及在导管架平台健康监测中的应用情况。文中发现傅里叶变换方法简单、适用性强,对于平稳信号有很好的处理效果;小波变换和希尔伯特-黄变换能很好地提取非平稳信号的时频特性,在导管架平台健康监测与特征提取中应用广泛。同时,随着人工智能算法的快速发展,未来的发展中,可以进行信号处理方法与人工智能算法的结合使用,以期获得更好的信号处理效果。     

海南岛东部海域生物污损研究

于１９８９年１０月－１９９０年６月,在位于海南岛东部海域的琼 东和琼东南海区,分别布设Ｗ１和Ｊ２两个浮标站,进行生物污损的挂板试验。     

Reliability-Based Full-Life Cycle Optimum Design of Offshore Jacket Platform

Based on the consideration of operation environment and structural property, an optimnm design model of offshore jacket platform is developed in this paper, namely, the reliability-based full-life cycle optimum design model. In this model, the time-dependent reliability assessment method for structural members is established by combination of the decrease, of sectional size and performance deterioration of material. The initial investment, maintenance cost and failure loss cost are assembled into the model. The total cost of the platform structure system in its full service period is chosen as the objective function, and the initial reliabilities of the layer elements partitioned in advance are taken as the design variables. Different models are obtained, depending on whether the system reliability eonstraint is considered or not. This optimum design model can result in the lowest full-life cost and the optimal initial layer reliability of an offshore jacket platform in the design of marine structures. The feasibility of this model is illustrated with an actual jacket platform in the Liaodong Gulf as an example.     

海洋油气开发项目用海范围界定关键问题及对策研究

文章对海洋油气开发项目用海范围界定过程中出现的问题进行了梳理,发现海上石油平台用海范围界定时出现的主要问题有平台外缘线归整尺度不统一、改扩建部分申请用海的要求不明确、水下生产系统用海缺少界定依据等;海底电缆管道用海范围界定时出现的主要问题有宗海内部单元划分不利于管理、交越和重叠处用海处理方式不统一、管缆间距过大形成的封闭区域申请用海的要求不明确以及部分项目界址点过多不利于海籍管理等。针对海洋油气开发项目宗海图绘制过程中出现的问题,文章提出了完善技术规范,为合理界定用海范围提供依据;规范管理,明确平台改扩建用海范围界定方法;开展海洋油气项目立体确权研究,探索三维海籍管理模式;强化集约节约用海,杜绝海洋空间资源浪费;探索建立新方法,合理绘制宗海图等对策建议,以助力我国海洋油气开发项目海域使用管理工作的顺利开展。     

胜利油田浅海石油开发区钢铁腐蚀规律

中国约有18000 km的海岸线，这使海洋的开发和利用在国民经济中所占的地位越来越重要。近年来已经建造了大量的海上采油平台、大型砂石及输油码头，埋设了大量的海底输油和通讯管线。为了缩短海陆距离，海上人工岛、跨海大桥以及海底隧道的建设也势在必行。这些工程设施的建设离不开钢铁材料，由于钢铁材料资源丰富、造价便 宜、强度大、韧性好易于加工等特点，长期以来单独或以钢筋混凝土形式被广泛应用。但由于海水是一种强电解质溶液，暴露于海洋环境中的钢构造物中的钢铁与周围介质发生电化学反应而受到严重腐蚀， 并且海洋中的风、浪、流、潮汐等水体循环运动也使其同时承受交变载荷的作用。两者的联合作用往往导致钢结构疲劳性能显著下降，大大降低了钢构造物的使用寿命。对于保证海上各种设施的安全并有效的延长其使用寿命，研究钢铁设施在不同海洋环境的腐蚀问题是一项重要工作(侯保荣，1999)。为了向胜利油田近海石油开发的海上钢铁构筑物的防护提供设计依据，作者通过在钢铁上分别挂片和电连接挂片技术在埕岛浅海对几种海洋用钢铁的腐蚀规律进行了现场研究。     

Dynamic behavior of offshore spar platforms under regular sea waves

Many innovative floating offshore structures have been proposed for cost effectiveness of oil and gas exploration and production in water depths exceeding one thousand meters in recent years. One such type of platform is the offshore floating Spar platform. The Spar platform is modelled as a rigid body with six degrees-of-freedom, connected to the sea floor by multi-component catenary mooring lines, which are attached to the Spar platform at the fairleads. The response dependent stiffness matrix consists of two parts (a) the hydrostatics provide restoring force in heave, roll and pitch, (b) the mooring lines provide the restoring force which are represented here by nonlinear horizontal springs. A unidirectional regular wave model is used for computing the incident wave kinematics by Airy’s wave theory and force by Morison’s equation. The response analysis is performed in time domain to solve the dynamic behavior of the moored Spar platform as an integrated system using the iterative incremental Newmark’s Beta approach. Numerical studies are conducted for sea state conditions with and without coupling of degrees-of-freedom.     

Probability models for offshore structural response due to Morison wave loading Part I: Drag-only response

Offshore structures are exposed to random wave loading in the ocean environment and hence the probability distribution of their response to wave loading is a minimum requirement for efficient probabilistic analysis of these structures. Due to nonlinearity of Morison wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian. Analysis of simulated data has, however, shown that neither of the two probability models proposed in the literature can accurately predict the tails of the response distribution. New probability models are therefore required to overcome this deficiency. This paper is composed of two parts: Part I is devoted to the development and validation of a new probability model for drag-only responses (i.e. responses due to the drag component of Morison wave loading), while Part II is devoted to the development and validation of new probability models for both inertia-only and total responses.