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.

轻量化整体液压顶升式钢平台在宁波曼哈顿大厦项目中的应用

宁波曼哈顿大厦标准层核心筒采用自主研发的轻量化整体液压顶升式钢平台,其以刚性桁架结构为主体,顶部整体钢平台可安装集成布料机,并悬挂核心筒墙体模板及4~5层操作平台,通过全作业面防护保障了多作业面穿插作业。介绍了该钢平台安装、运行、拆除施工流程及重难点管理。实践表明,采用该钢平台施工,缩短了主要工序时间,从而有效缩短了核心筒标准层工期。

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。

特殊工况下大型通用门式起重机基础设计可靠性验算

某长江大桥建设工程设置了水上施工平台,用于布置一台180 t通用门式起重机,主要用来吊运钢箱。该起重机的基础较特殊,是全钢管柱架构的施工平台,且位于长江之上。为了确保起重机使用安全,对其基础设计进行了计算,并通过有限元建模,计算整体结构的强度,再对应力最大处的钢管进行稳定性验算,来验证起重机基础的安全性。

数字化等离子焊接系统在连续油管钢带对接中的设计与应用

为解决传统等离子焊接平台气囊夹紧力不足、焊枪行走机构精度差、焊接控制系统输出不稳定、无法实时观察问题,以及造成的对接焊缝错边、咬边、焊偏等质量问题,设计了一种数字化等离子焊接系统。该系统通过改进液压夹紧装置、设计焊枪控制系统、熔池监控装置、焊机自动定位装置及气体保护装置,实现了数字化焊接,提升了焊接质量,提高了生产效率。实际应用表明,采用设计的数字化等离子焊接系统,生产效率提升15%以上,斜焊缝一次通过率提高约8%。

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。

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。

大型履带式起重机行走钢平台设计与分析研究

针对采用大型履带式起重机对钢结构部件进行吊装时地下室顶板加固成本较高的难题,提出了一种模块化钢平台对地下室顶板进行加固的方法,并对该平台的承载力和变形进行分析,提出了合理的使用建议。同时,对使用中的安全和环保措施进行分析和提议。

基于国外某矿厂码头的结构方案研究

在某矿厂码头工程设计中,利用矿厂采矿废石料回填造陆价格低廉的优势,提出了高桩梁板式结构、钢管板桩组合结构、钢管排桩结构方案并开展分析研究。在高桩梁板式方案中,为减少前方承台与后方陆域距离,采用了一种可以适应较大水深卸荷承台式接岸结构。钢管板桩组合结构和钢管排桩结构虽然均为板桩结构,但相对于钢板桩,钢管桩单桩水上可打性更好,因此分别对其采用了填筑施工围堰的陆上打桩施工方式和打桩船打桩的水上打桩施工方式。最终通过综合技术经济比选,选定了适用于本工程的最优结构方案,为提高钢排桩板桩结构的应用前景提供经验。

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。

双相不锈钢管材在海洋石油平台的应用与研究

双相不锈钢是一种具有双相组织的高强度不锈钢材料,其主要组成为铁素体和奥氏体,因此具有铁素体较好的强度和塑性,又具有奥氏体优异的耐腐蚀性能,被广泛应用于海洋石油平台的建造领域。文章针对双相不锈钢的特性、施工工艺、质量控制、原因分析,结合施工方法及施工经验做简要分析及总结。

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。

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。

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。

单元式整体提升集成平台模架装备技术研究

温州市瓯海区南单元D区西片地块项目主楼高339m,采用了单元式整体提升集成平台模架施工,该套模架装备利用导轨立柱承重,油缸相互交替顶升,以往项目通常应用于覆盖整个核心筒。该工程主楼核心筒可利用面积较小,为提高单元式整体提升集成平台模架的施工效率及安全系数,将其小型化并集成超长液压布料机。小型化的模架装备用钢量低,有效降低了施工成本;下挂筒架作为操作平台保证了电梯井道墙体的施工安全;集成的液压布料机随平台同步爬升,避免了传统布料机每次浇筑需利用塔吊上下驳运的缺点;此套模架装备提高施工效率,施工安全系数高,提高了我国超高层施工中施工装备的技术水平。

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。