Multilevel Optimal Design of Prestressed Lightweight Concrete-Steel Platform Structures

The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. If the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms.

Calibration of LRFD Format for Steel Jacket Offshore Platforms in China Offshore Area(1) :Statistical Parameters of Loads and Resistances

The statistical characteristics and parameters of loads and resistances are systematically studied for the development of probabilistic limit state design method for steel jacket offshore platforms in the China offshore area. The mean value, standard variance and distribution pattern of resistances and loads in different base perieds are presented. The statistical parameters of structural member resistance, self-weight, deck live load, and environmental loads such as wind, wave, current and ice, which are drawn on a large amount of observatian data of offshore environmental factors, and the design data of platforms in China Bohai Sea form the data set, providing a necessary basis for the calibration of load and resistance factors to realize the reliability-based design of jacket platform structures.

Calibration of LRFD Format for Steel Jacket OffshorePlatform in China Offshore Area(2): Load, Resistance and Load Combination Factors

Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are introduced. Then, the ratio of live load effect to dead load effect is estimated. The target reliabilities for design of offshore structures in China offshore area are calibrated by past practice in API RP2A-WSD code. The load and resistance factors are optimized by minimizing the difference within the target reliability and the resulting reliability over the range of load effect ratios. Considering the concurrence of different loads, load combination factors are obtained through an optimization process, and the relation between the load combination factor and load correlation coefficient is established. Finally, the design formulae for steel jacket structures in China offshore area are recommended.

A Novel Named Entity Recognition Scheme for Steel E-Commerce Platforms Using a Lite BERT

In the era of big data,E-commerce plays an increasingly important role,and steel E-commerce certainly occupies a positive position.However,it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs.In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms,we propose a novel deep learning-based loss function for named entity recognition(NER).Considering the impacts of small sample and imbalanced data,in our NER scheme,the focal loss,the label smoothing,and the cross entropy are incorporated into a lite bidirectional encoder representations from transformers(BERT)model to avoid the over-fitting.Moreover,through the analysis of different classic annotation techniques used to tag data,an ideal one is chosen for the training model in our proposed scheme.Experiments are conducted on Chinese steel E-commerce datasets.The experimental results show that the training time of a lite BERT(ALBERT)-based method is much shorter than that of BERT-based models,while achieving the similar computational performance in terms of metrics precision,recall,and F1 with BERT-based models.Meanwhile,our proposed approach performs much better than that of combining Word2Vec,bidirectional long short-term memory(Bi-LSTM),and conditional random field(CRF)models,in consideration of training time and F1.

A new bracing system for improvement of seismic performance of steel jacket type offshore platforms with float-over-deck

In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.

AHP-改进物元法在整体钢平台顶升模架体系安全风险评估中的应用

针对整体钢平台顶升模架体系施工安全性的灰色特征,经实地调研及专家评审,建立了整体钢平台顶升模架体系的安全风险评估模型。首先,考虑人员、设备、环境、管理及技术5个方面,选取19个指标构建安全风险评估指标体系;其次,采用层次分析法计算各指标权重,基于改进物元法确定各指标的风险等级,然后将两者向量相乘,以最大隶属度原则确定整体钢平台顶升模架体系的安全风险等级;最后,将所建立的基于层次分析法(Analytic Hierarchy Process, AHP)-改进物元法的安全风险评估模型应用到某超高层工程实例中,并将评估结果与实际施工情况对比分析。研究表明,该评估模型的计算结果合理且准确可靠,可为超高层整体钢平台顶升模架体系的安全管理提供参考。

超高层大悬挑钢结构平台钢拉索施工技术

以某超高层悬挑钢结构平台预应力拉索为研究对象,在确保结构受力安全的前提下,对新型空间钢拉索结构的安装及张拉进行深入研究,通过有限元软件对各阶段进行分析模拟计算,了解结构受力特点,模拟各工况下施工受力,在工期紧张环境下能够及时调整施工方法,通过过程施工监测,确保拉索施工顺利进行,经过分析、深化设计、测试、施工全过程模拟,最终实现大悬挑钢结构平台钢拉索固定,实现其使用功能。

钢铁产业互联网平台与企业价值提升——基于微观企业数据的实证分析

钢铁产业互联网平台作为一种新兴商业模式,正在迅速崛起并深刻影响着钢铁行业的发展。研究基于微观企业数据,实证检验钢铁产业互联网平台对企业价值提升的影响,发现加入钢铁产业互联网平台能够显著提升企业价值。从政府、平台和企业角度对于钢铁产业互联网平台的未来决策与发展提供相关建议,扶持钢铁企业入驻钢铁产业互联网平台,平台本身可以进行多方面优化以提高供应链的协调性和运营效率,钢铁企业可以利用平台降低库存成本、提高物流效率,提升企业价值。

现浇框架仓储厂房钢平台支模技术分析与应用研究

依托超高超跨现浇混凝土框架仓储厂房,为避免巨量高支模搭设,设计了钢平台支模体系。钢平台主体采用321型贝雷架+加长桁架的形式,可以适用于不同跨度、宽度的大跨梁支模,通用性较好,便于周转使用。使用大型有限元软件对钢平台支模技术进行了施工过程模拟分析,研究表明,钢平台承载力高、刚度大,最大应力比为0.68,有较大安全储备,施工完成后结构挠度较小,可以满足规范要求;楼板安装及浇筑时,钢平台分担的增量荷载较小不超10%;提出的钢平台分担比例估算方法,其计算结果与有限元解接近,且对于钢平台设计偏安全。在项目实施过程中进行了混凝土肋板堆载试验、钢平台堆载试验以及施工监测。根据混凝土肋板试验结果对其设计参数进行了优化;钢平台堆载试验结果表明其挠度及承载力均满足要求;施工监测结果与有限元结果吻合较好。

数字孪生在钢平台设计施工中的应用实践

为推动超高层建筑数字化转型,提出了基于数字孪生的钢平台五维模型。以实际超高层建筑项目作为工程背景,阐述了利用数字孪生集成多种智能技术实现项目虚实交互的方法,提升超高层项目信息化、智能化水平,推动项目数字化管理,为钢平台的智能化施工作业提供一定的参考。

中庭钢结构采光顶操作平台施工方案比选研究

采光顶在大型公共场所应用普遍,通常采用搭设落地脚手架作为其施工的操作平台,但落地脚手架的搭设影响了中庭其他工序的开展。以2个大型商业项目的中庭施工为例,分别拟定钢丝绳拉索平台和钢网架平台2种方案,并对2种方案从安全、工期、费用、适用性等方面进行分析、对比和总结,为类似工程采光顶操作平台形式选择提供参考。

多机协同塔机阶梯式爬升高效建造技术研发与应用

为深入解决模架装备施工爬升节奏与塔式起重机自升进程不一致所产生的冲突问题,基于多机协同的理念,在单元式钢平台与塔式起重机分体独立工作的基础上,通过多种协同装备的融合作业,实现塔式起重机的阶梯式爬升,并利用建立的数字化动态交互镜像模型进行最优化建造模式理论分析,得到多种适用于不同动力系统塔式起重机的阶梯式爬升高效建造模式,并将其应用于具体的超高层项目。工程应用结果表明:多机协同塔机阶梯式爬升高效建造技术适用于不同类型的超高层项目,且有利于超高层项目降本增效,增强施工安全性,提高智能建造水平。

钢板桩围堰在桥梁施工中的应用分析

本文以某高速公路特大桥桥墩承台钢板的围堰的施工为研究基础,分析如何选择承台施工围堰方案,并从多方面介绍钢板围堰技术的要点,主要包括围堰结构形式选用、材料及设备进场要求、桩板桩插打及合拢注意事项、内撑系统施工要求、承台封底砼施工方案,从而为钢板桩围堰在桥梁施工中的应用提供理论指导。

结构不规则变形建筑的整体钢平台动态爬升控制

为解决超高层建筑不规则变形结构施工技术难题,并确保整体钢平台模架装备动态爬升的安全性,采用基于电液比例同步控制的液压系统和PLC控制系统,实现了高精度的同步控制。通过设置水平度传感器系统,实时监测整体钢平台竖向变形情况,并应用远程智能监控系统,实时监测钢平台爬升过程中的数据,确保了钢平台的安全爬升。通过以上方法实现了超高层建筑不规则变形结构的整体钢平台施工安全状态监控,提高了现场施工作业信息化水平,并确保了施工过程的安全性。

钢管悬挑扩宽平台在某大型博物馆中的设计验算及施工应用

结合某国家级大型博物馆项目中全钢管悬挑扩宽平台的设计验算及施工应用,详细说明了该方案具有造价低、工期短、合理利用已有脚手架等优点,通过全面科学的验算证明其在承载能力和稳定性上满足要求,并总结了钢管悬挑扩宽平台的关键工序和施工要点。

超高层顶模安装施工技术应用

以某超高层塔楼为对象,通过智能顶升模架系统,使塔楼核心筒竖向结构施工有一个封闭、安全的作业空间某项目智能顶升模架系统安装高度为33.4 m。智能顶升模架系统安装重点是钢平台系统和挂架系统的安装;钢平台的安装原则“地面拼装、空中对装”,挂架安装原则“三跨单元、单元吊装”。

浅析海洋平台海水系统管材--钢骨架塑料复合管材

海水系统管材作为海洋石油平台上常用的管材,在使用过程中,受海上复杂多变的环境影响及管道内介质本身的特性,使得传统碳钢金属管道的内外壁受到不同程度的锈蚀、腐蚀,从而造成一定的破坏。钢骨架塑料复合管解决了这一问题,在海洋石油平台的海水、污水、消防水等系统得到广泛使用。由于其优良的综合性能,有望逐渐取代传统的碳钢金属管道。

浅析海上油气平台钢结构腐蚀环境及防腐技术应用

海上油气平台是石油和天然气生产的关键设施之一,其安全性与可靠性对海洋环境下的油气生产至关重要。我国在南海、渤海、东海等海域的油气田开发建设中,面临着海上高/低温、高湿度、高盐分等恶劣环境条件。因此,分析了探讨海上油气平台钢结构的腐蚀特点、腐蚀机理以及目前海上油气平台钢结构主要的防腐蚀方法,为海上生产装置的安全运行提供有力的保障。

跨泄洪道连续梁施工辅助索道便桥及钢平台设计与施工关键技术研究

某特大桥(44+2×72+44)m连续梁跨越泄洪河道,地理环境复杂,桥梁下部结构施工面临诸多难题。文章以该桥主墩下部结构施工作为切入点,展开了跨泄洪道连续梁施工辅助索道便桥及钢平台设计与施工关键技术的研究,重点阐述了跨泄洪水道处桥梁下部结构施工的难点、索道便桥及钢平台的结构设计及特点、有限元建模计算分析流程、施工关键技术等,目前该施工辅助索道便桥及钢平台已在该桥的下部结构施工中成功应用,为将来类似深沟、峡谷等特殊地理环境下的桥梁工程人员通行及物料运输便桥结构形式选择及施工提供了宝贵经验。