Currently, the construction process of large offshore platforms worldwide involves building the topside and hull separately and then having them integrated. Jacking technology is emerging as a new integration method more suitable for offshore platform construction for its higher tonnage and larger scales compared with the lifting technology. Conventionally, an overlapped support tower (OST) is adopted to jack the topside to a predetermined height. However, with the OST’s increasing jacking height, the wind load effect becomes more significant, which in turn limits the OST height and applications. In this paper, failure criteria were developed for the OST based on the load types and structural characteristics of easy assembly and disassembly. Then a simplified method to simulate the OST was proposed. In addition, a finite element model (FEM) of the entire jacking system with the topside and OST (including 6 jacking towers, 8 strand cables and 23 bracing pipes) was established, and wind-induced vibration analysis was performed to ensure safety of the jacking system. The results show that the addition of the topside increases the torsional effect of the jacking system; the unfavorable wind angles are 0^∘ and 15^∘, which should be paid much attention during the jacking operation. The recommended wind-induced vibration coefficients for the OST and topside are 3.0 and 4.0, respectively. The proposed method and simulation results of this study provide a reference for the jacking and integration design of similar offshore platforms.

中文翻译：

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海洋平台顶升系统的失效准则和风致振动分析

目前，全球大型海上平台的建造过程包括分别建造顶部和船体，然后将它们整合在一起。与起重技术相比，顶升技术具有更高的吨位和更大的规模，是一种更适合海洋平台建设的新型集成方式。传统上，采用重叠支撑塔（OST）将顶面顶升到预定高度。然而，随着OST顶升高度的增加，风荷载效应变得更加显着，进而限制了OST的高度和应用。本文根据载荷类型和易拆装的结构特点，制定了OST的失效准则。然后提出了一种模拟OST的简化方法。此外，建立了包括顶侧和OST（包括6座顶升塔、8根绞索和23根支撑管）的整个顶升系统的有限元模型（FEM），并进行了风致振动分析，以确保顶升系统的安全。结果表明，增加顶面增加了顶升系统的扭转效应；不利风角为0^∘和 15 ^∘，在顶升操作中要特别注意。OST 和上部的推荐风致振动系数分别为 3.0 和 4.0。本研究提出的方法和仿真结果可为类似海洋平台的顶升一体化设计提供参考。