Seismic response and correlation analysis of a pile-supported wharf to near-fault pulse-like ground motions

Earthquake investigations have shown that near-fault pulse-like(NF-P)ground motions have unique characteristics compared to near-fault non-pulse-like(NF-NP)and far-field(FF)ground motions.It is necessary to study the seismic response of pile-supported wharf(PSW)structures under NF-P ground motions.In this study,a three-dimensional finite element numerical model is created to simulate a PSW.By imparting three types of ground motion,the engineering demand parameters(EDPs)of PSW under NF-P ground motions were analyzed and compared,in which EDPs are the maximum displacement and bending moment of the piles.Twenty intensity measures(IMs)were selected to characterize the properties of ground motions.The correlation between IMs and EDPs was explored.The results show that the piles present larger displacement and bending moment under NF-P ground motions compared to NF-NP and FF ground motions.None of the IMs have a high correlation with EDPs under NF-P ground motions,and these IMs are more applicable to FF ground motions.The correlation coefficients between EDPs and IMs under three types of ground motion were obtained,which will provide a valuable reference for the seismic design of PSWs.

Comparative analysis of seismic response characteristics of pile-supported structure

In order to analyze the seismic response characteristics of pile-supported structure,a computational model considering pile-soil-structure interaction effect was established by finite element method.Then,numerical implementation was made in time domain.At the same time,a simplified approximation for seismic response analysis of pile-soil-structure system was briefly presented.Furthermore,comparative study was performed for an engineering example.Through comparative analysis,it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method.These results show that spectrum characteristics and intensity of input earthquakes are two important factors that can notablely influence the seismic response characteristics of superstructure.When the input ground motion acceleration amplitude gradually increases from 1 to 4 m/s2,the acceleration of pier top will increase,but it will not be simply proportional to the increase of input acceleration amplitude.

Study on Structure of Arched Longitudinal Beams of Deep-Water Wharf

High-pile and beam-slab quays have been widely used after several years development. They are mature enough to be one of the most important structural types of wharves in China coastal areas. In order to accommodate large tonnage vessels, wharves should be eorrstructed in deep water gradually. However, conventional high-pile and beam-slab structares are hard to meet the requirements of large deep-water wharf. According to arch＇ s stress characteristics, a new type of wharf with catenary arched longitudinal beams is presented in this paper. The new wharf structure can make full use of arch＇s overhead crossing and reinforced concrete compression resistance, improve the interval between transverse bents greatly, and decrease underwater construction quantity. Thus, the construction cost cab be reduced. Take the third phase project of the Yangshan Deep-water Port for example, comparative analysis on catenary arched longitudinal beams and conventional longitudinal beams has been made. The result shows that with the same wharf length and width, the same loads and same longitudinal beam moment, catenary arch structure can improve the interval between bents up to 28 m, decrease the nmnber of piles and underwater construction quantity.

Statistical Analysis of Ship Impact Forces on Light Wharf Structures

In the present study,the formula calculating ship impact forces on light wharf structures is presented when the elastic deformation of the hull and the pier structures as well as the nonlinear deformation of the fender are taken into account. The ship impact forces are statistically analyzed with the Monte-Carlo method according to the known probability distribution types of random variables.Based on the simulated results, the distribution of ship impact forces which is characterized by bimodal distribution can be expressed as the combining probability density function of beta distribution and normal distribution. The corresponding parameters of the probability density function can be estimated with the maximum likelihood method. The results show that ship impact forces on light wharf structures follow the distribution of type I extreme value.The mean coefficient and variation coefficient are 1.11 and 0.008 respectively during 50 years of design reference period.

New Types of Wharf Structures in Chiwan Port

A bold innovation was carried out for the structural type of wharves in line with local conditions in Chiwan Port, in which a group of wharves with novel structures have been built in this port during the past ten years.

Analysis on kinematic and inertial interaction in liquefiable soil-pile-structure dynamic system

The dynamic pile-soil interaction in a liquefied site was investigated by means of numerical simulation and shaking table tests in this study.Based on the results from the shaking table experiment,the cross-correlation analysis of the soil displacement-pile bending moment and superstructure acceleration-pile bending moment was performed to study the influence of kinematic interaction and inertial interaction on the seismic response of piles.A relatively reasonable and accurate finite difference numerical analysis model of liquefiable soil-pile group-superstructure dynamic system was established.Through numerical simulation,the understanding of kinematic interaction and inertial interaction in the shaking table test was verified.The mass,damping and period of the superstructure were selected as variables to carry out parameter analysis to further study the influence of inertial interaction on the pile-structure failure mechanism.The results show that the influence of kinematic interaction on the pile was much greater than that of inertial interaction.The mass of the superstructure was the most important parameter of inertial interaction,and dynamic characteristics of the superstructure also had an effect on inertial interaction.The effect of inertial interaction on the part near the pile tip was more significant,indicating that the failure near the pile tip is closely related to inertial interaction.

防波堤和码头一体的双圆筒沉箱结构设计

针对兼具作业和防浪功能于一体的直立式双圆筒沉箱结构设计,提出船舶作业期间平均越浪量≤0.1 L∕(s·m)和风暴期间(100 a一遇)越浪量≤50 L∕(s·m)的高程控制标准。研究双圆筒采用混凝土薄板和厚板2种连接方式,并对其受力特性、计算模型、内力情况进行介绍。总结直立堤护底设计的推荐计算方法,发现CEM图表法与3D物模试验一致,OCDI法计算结果偏大,国标查图法计算块体稳定质量偏小。研究海侧挡浪墙设置在圆沉箱中部并设置反弧角的结构方案,提出的EurOtop法适用性广且结果贴近试验值;提出预制工字块封堵沉箱间填料并采用厚板连接堤头4个沉箱成整体的堤头保护方法;通过开展2D、3D模型试验验证了结构方案的可行性。研究成果可为类似设计提供参考。

高桩码头系缆墩和钢联桥一体化结构创新设计

针对由装卸平台、系缆墩、钢联桥组成的一字形布置高桩墩式码头,常规的设计思路考虑三者独立受力,弱化各结构之间的传力效应。从三者协同受力的角度出发,提出一种适应于特定布置形式的系缆墩和钢联桥一体化结构设计方案,结合工程案例介绍该结构的形式和受力分析方法,并从受力和造价方面与传统的高桩墩台方案进行比较。结果表明:在满足使用功能的前提下,一体化方案有利于发挥结构的整体受力优势,减少系缆墩和钢联桥的工程量,降低工程造价。

岸坡淤积对高桩码头结构受力的影响及清淤防治措施

利用有限元方法分析了岸坡淤积对高桩码头结构受力的影响,提出了码头下方局部清淤联合码头后方开挖以减小淤积影响的防治措施。通过构建高桩码头排架结构的实体单元模型,探讨了岸坡淤积和使用荷载的耦合作用对码头结构内力及水平位移的影响;通过比较岸坡淤积过程中的桩基受力及变形,揭示了桩基损伤机理,即岸坡淤积使桩土相互作用面积增大,桩基受到的附加淤积土压力作用增大,导致受横梁约束桩基的桩顶弯矩增大。岸坡淤积对码头结构存在显著影响,随着淤积高度的增加,桩基的内力及水平位移、横梁的水平位移显著增大;码头岸坡淤积、码头后方超淤及船舶撞击力的联合作用,对淤积岸坡的坡顶处和后侧的向岸斜桩的内力影响最大,桩基最易受损;对码头下方的淤积坡肩进行局部清淤,联合在码头后方挖槽的清淤措施,可有效降低危险桩基的桩顶弯矩,减小淤积对码头结构的影响。

堆场堆载作用下岸坡及高桩码头响应特性研究

堆场长期堆载会导致软土发生明显变形,影响岸坡稳定并威胁临近码头结构在运维期的安全性。以天津港高桩码头结构为工程背景,建立软土、高桩码头与荷载的三维有限元分析模型,研究了堆场堆载作用下软土岸坡及高桩码头结构响应特性。研究结果表明:堆场堆载会导致地表出现明显沉降变形,同时接岸结构下方软土会发生侧向运动;后承台靠近堆场处的桩基会发生显著的水平变形并在顶部产生明显的弯矩响应,易于导致桩帽位置处混凝土开裂损伤;堆载宽度的减小对土体与结构的位移峰值影响较小,但会显著影响堆场土体的沉降范围;在后承台无堆载工况下,桩帽与上部结构间会出现相对滑移,易于造成构件之间的错位破损。

深厚泥炭质土软基条件下的老码头改扩建

泥炭质土因其有机质含量高、含水量高、压缩性高、强度低、固结慢等特点,加固处理难度较大,严重危害工程安全。依托某境外老板桩码头改造项目,针对其存在深厚泥炭质土软基、堆场面积狭小、老码头结构破损严重、改造空间受限、边改造边运营等突出特点,拟定多种改扩建平面和结构方案。从码头运营、结构可靠性、经济性和施工难度等方面分析各方案优缺点,最终提出适应深厚泥炭质土软基条件下老码头改扩建工程的推荐方案,并分析了施工过程中关键技术难点及注意事项,可为类似工程提供借鉴。

重力式沉箱码头施工工艺研究应用

为解决重力式沉箱码头在制作、运输和安装施工中的难题,以某新建500 t沉箱重力式客货码头为研究对象,在分析场区地质条件的基础上,研究了重力式沉箱码头各个施工环节的工艺流程,并进行沉降量观测。

坦桑尼亚坦噶港老码头改造关键技术

坦桑尼亚坦噶港老码头改造工程面临深厚泥炭质土软基、改造空间受限以及老码头严重破损等不利条件。采用适用于深厚泥炭质土软基的后板桩接岸式高桩码头结构,采用高压旋喷桩对码头岸坡进行加固,确保码头结构的安全性;采用Plaxis 3D有限元数值分析方法对水泥土桩的内部和外部稳定性进行复核;针对高有机质土中的高压旋喷桩的成桩质量难控的问题,采用降低浆液压力、采用复喷工艺、降低浆液水灰比、外掺石膏等措施提升了旋喷桩的成桩质量。

综合保障码头管沟结构设计

针对综合码头管线品种和数量增多,管线敷设难度增大的问题,提出一种新型的管沟结构设计,能方便多管线的敷设和维护,满足管线布置及人员通行要求。通过在传统上横梁前沿和后沿局部开设孔洞,搁置管沟纵梁,形成一个贯穿于码头面以下的空间体系,释放高桩梁板码头双层使用功能。采用Midas Civil计算软件三维实体单元建模,对内力进行计算和分析,结果表明:横梁结构内力满足规范要求;并将码头结构水平横向分配系数与规范分配系数进行比对,数据基本一致,确保了排架水平力横向分配的安全性和合理性。该结构设计可为同类型码头提供借鉴与参考。

新型桩基-重力式复合码头结构的可靠度分析

针对外海深水条件下码头结构面临的浪大流急的恶劣环境挑战,结合常规桩基与重力式码头结构的优点,采用重力式沉箱与桩基相结合的新型复合结构,可有效节约施工工期,减少工程费用。通过与试算工程传统结构的比较,确定和优化了复合结构断面设计和参数。借鉴重力式结构计算模式,考虑复合结构的材料性能、几何参数和设计荷载等随机变量,用JC法计算新型复合结构的抗滑、抗倾可靠指标,结果表明该复合结构是合理的。

基于空间悬浮的码头结构安全数字孪生技术研究

码头结构健康监测是保障港口安全稳定运行的重要手段。基于虚实映射的码头孪生体建模理论,提出了多源数据融合的可视化增强方法和多源信息人机交互协作技术,构建了码头结构及监测体系的数字孪生体模型,并以空间悬浮显示装备为载体,实现了码头结构体安全监测数字孪生体的可视化展现和自然式交互,是码头结构安全维护的全新探索。

高桩梁板码头系船柱下方空间穿管结构设计

为提高高桩梁板码头下方空间的利用率,并使管线敷设更为有序化和集约化,结合工程案例,提出了在系船柱结构基础内穿管的设计理念,有效缩短了管线路径、减少了转弯接头。对比预留孔和预埋套管2种敷设方式,从结构受力、耐久性、施工期安装和使用期检测等多方面综合考虑,提出了推荐方案。通过Midas Civil三维软件单元建模,对系船柱扩大段等各节点进行复核计算分析,并在施工完成后,对系船柱进行原位加荷测试试验,双向验证系船柱基础下方开孔对码头结构的整体稳定性影响较小,码头结构安全可靠。

老旧高桩码头结构检测案例分析

经过改革开放40多年的发展,我国沿海港口建设发展迅速,随之而来的关于老旧码头的健康问题也逐渐显露,针对老旧码头的检测评估显得愈发重要。根据《水运工程水工建筑物检测与评估技术规范》和《港口码头结构安全性检测与评估指南》的相关规定,以不同时期建设的两座老旧高桩码头为背景,结合常规检测方法、测量手段,指出检测工作中的重点,并对检测结果进行比较,分析了上海地区老旧高桩码头破损的原因,同时提出合理的建议,可为老旧高桩码头的检测提供参考。

钢管板组合桩结构特点及施工工艺

港口码头施工的过程中需要做好板桩码头桩基施工工作,桩基的质量决定着后续工程的施工质量。随着港口建设的不断发展,对码头质量要求逐步增高,传统的板桩结构已不能满足码头结构大型化、深水化的要求,因此钢管板组合桩结构形式逐渐得到了广泛应用,此类组合在复杂的地质情况下仍能适应,并且具有力学性能好、施工较为简单、工期短和经济效益高等特点。以印度尼西亚锦江码头工程为例,介绍该结构特点及施工工艺。

大直径圆筒码头结构土压力性状模型试验

详细说明了大直径圆筒码头结构的模型试验布置、量测和试验方法。通过室内模型试验 ,研究大直径圆筒码头结构在不同的筒高、筒高与筒径之比、埋深与筒高之比、基床垫层等条件下 ,圆筒内外侧土压力、筒体基底反力的分布规律。