A dynamic model for marginal cost pricing of port infrastructures

ABSTRACT

A dynamic model for marginal cost pricing of port infrastructures links costs to system performance by combining a power-law function with time-dependent queueing analysis. Additionally, the model incorporates the marginal cost of capacity, including the effects of economies of scale. This allows the calculation of the marginal cost price under a dynamic framework. The model accounts for nonlinear behaviour of port demand, which is sensitive to price and service levels. The effects over time of cost and service levels on the port’s operational performance are quantified. The proposed model allows determining the optimal timing for capacity investment. The model is a starting point for the application of marginal cost pricing to ports. However, for practical application of such pricing method it is necessary to apply a system’s approach, as productivity and costs must be assessed at the terminal’s component level. This should allow the derivation of a marginal cost function at the terminal’s component level.     

An inverse finite element method for the analysis of VIV data

This paper presents an algorithm for the frequency domain solution of dynamic linear “inverse” problems, that is for the processing of measurement data (strain, acceleration etc.) acquired on a mechanical structure, in order to estimate the loads acting on the structure and its corresponding response. The problem is formulated as a constrained (force equilibrium) optimization (small deviations from measurements, small loads) problem, which is transformed into an unconstrained problem, then into differential equations. The algorithm is applied to the estimation of hydrodynamic forces induced by the shedding of vortices from an offshore oil riser.     

Prioritization of failure risk in subsea flexible pipes via data envelopment analysis

Risk-based inspection is nowadays the predominant approach to structural integrity assurance in complex engineering systems, such as those designed for and operated in deepwater environments. One of the major tasks in risk-based planning is risk ranking of the components comprising an engineering system. In this paper, a mathematical model based on data envelopment analysis is developed for this purpose, whereby two types of weights are employed: subjective judgmental weights which are provided as input, and objective which constitute the output of the model. The use of the mathematical model is illustrated in a real world system of subsea flexible pipes, which operational in the south Atlantic Shelf off the Southeast Coast of Brazil.     

297000dwt超大型油船噪声源分析及控制

研究了船舶噪声的主要来源,揭示了297000dwt超大型油船噪声源的分布规律,对实例噪声结果作了对比,并分析了噪声产生的原因及采取的降噪措施。     

三峡工程明渠汛期通航船舶绞滩缆桩强度分析

用有限元分析了驳船缆桩及周围甲板在绞滩力作用下的受力状况,据此对局部结构提出了加强要求。     

2014年中国城市轨道交通运营线路统计与分析

截至2014年底,中国内地共有22座城市拥有城市轨道交通运营线路,总长3 155 km,新增运营里程409 km。统计运营线路的名称、里程等情况,并对统计口径和特别情况予以说明。给出2014年中国各城市的轨道交通运营线路数量和里程排序。北京以19条线位居运营线路数量首位,上海以643 km位居运营总里程首位。     

软基中拱桥桥台位移分析及优化方案

基于工程实例对软基中某无铰拱桥桥台位移进行有限元分析,讨论分析过程中特殊非线性的处理方法,并在原设计基础上对桥台进行优化分析。研究结果表明:优化后桥台位移减小,且与实测值吻合,结构内力分布更加均匀,结构处于安全状态,从而也证明本文分析的合理性,所提出的优化变更方案是切实可行的,达到了预期的效果,对同类工程问题具有参考价值。     

地铁车站结构截面控制内力计算分析

目前,在地铁车站结构设计中,一般采用将荷载满布到结构模型进行内力分析,并未考虑不同活载布置对结构内力的影响,从而导致部分截面设计存在安全隐患。文章以成都地铁3号线一期工程红牌楼南站结构模型为例,运用MIDASGEN有限元分析软件对不同活载布置下结构的内力进行比较,得出地铁车站各截面控制内力所对应的活载布置,为地铁车站结构设计提供借鉴。     

预应力混凝土槽形梁静力行为研究

为了解槽形梁静力行为,进行了一片预制预应力混凝土槽形梁的模型试验,分别考虑跨中最大弯矩及梁端最大剪力两种荷载工况对试验模型进行加载,测试了试验模型的控制断面的应力、变形.并采用非线性有限元分析方法对槽形梁的力学特性进行了研究.试验和研究得到了如下结论:该槽形梁的剪力滞效应较为突出,具有明显的开口薄壁杆件特征,底板的空间板效应明显,在设计荷载作用下结构处于线弹性状态,具有一定的安全储备.     

天津西南环线铁路钢横梁框架墩设计

当前,新建铁路临近市区或车站地段,往往铁路密集、纵横交错,新建线路与既有铁路、公路小角度交叉的情况不可避免;加之临近车站时线路纵断面抬高困难,需严格限制上跨线路的结构建筑高度.钢横梁框架墩的建筑高度较低,而横向跨度相对较大,是此类工点较好的解决方案.本文介绍了钢横梁框架墩的结构特点,分析比较了不同的墩顶固结方式,并总结了设计注意事项.