预应力混凝土箱梁施工裂缝分析与防治

本文通过对预应力钢筋混凝土箱梁施工裂缝产生原因进行展开分析,提出了防治措施。     

浅谈钢筋混凝土现浇箱梁温度与收缩裂缝的产生与控制

本文主要对广州市东山口立交及茂生围高架钢筋混凝土现浇箱梁裂缝产生的原因进行分析并提出控制收缩裂缝开展的施工措施。     

大跨度预应力混凝土连续梁桥常见病害及防治对策

预应力砼连续箱梁桥裂缝产生的原因很多,本文对预应力混凝土箱梁桥在建设和运营过程中出现的一些主要裂缝进行了分析研究,并提出了预防裂缝的措施。     

箱梁裂缝控制

以漠阳江西河大桥混凝土连续箱梁施工工程为例,就工程结构裂缝问题进行论述,提出在箱梁施工中有效控制裂缝的措施,并取得较好的效果。     

贵州山区超高墩大跨连续刚构设计问题与对策

针对贵州山区超高墩大跨连续刚构箱梁出现裂缝、挠度过大等问题,以肇兴大桥为背景,对超高墩、箱梁裂缝、跨中下挠问题提出了设计对策。     

浅析预应力混凝土连续箱梁裂缝产生的原因

文章就江苏省杨溧高速公路某标段现浇高标号预应力砼连续箱梁裂缝产生的原因、施工应该注意的事项进行了较为详细的阐述,以供同类型桥梁施工参考。     

高架桥连续箱梁的施工

结合上塘高架延伸线工程,本文阐述了高架桥预应力钢筋混凝土连续箱梁的施工工艺。     

连续刚构桥顶板纵向裂缝成因分析及设计反思

结合某高速公路全线的4座连续刚构桥的箱梁裂缝病害情况,对预应力混凝土连续刚构桥的常见病害进行了分析,并重点分析了箱梁的顶板裂缝病害成因,对原设计进行了反思,探讨了结构设计中应当注意的构造尺寸、配筋等细节问题,并给出了相应的优化建议。     

钢筋混凝土桥梁裂缝成因分析与对策

钢筋混凝土桥梁在建造和使用过程中,出现裂缝比较普遍。作者将钢筋混凝土桥梁的裂缝分为5类:荷载裂缝、温度裂缝、收缩裂缝、沉降裂缝、腐蚀裂缝,分析了钢筋混凝土桥梁各种裂缝产生的原因,提出了各种裂缝的控制措施、裂缝治理原则和修补方法。     

浅谈混凝土箱梁施工中裂缝成因与对策

混凝土箱梁在现代建筑中广泛采用,其裂缝现象也经常发生。笔者通过自身工作经验和参考大量文献资料,分析了混凝土箱梁施工中产生裂缝的原因,并且提出了对策。     

与世界经济一起成长--阿联酋国际航空货运部彼得·塞格利副总裁一席谈

5月12日,对于阿联酋国际航空公司来说,又是一个大喜的日子.就在这一天,阿联酋国航空公司在上海金茂大厦被授予"飞抵中东最佳货运航空公司"奖牌,成为全球唯一一家连续第16年获此殊荣的航空公司.在2004年航空货运博览会上,阿联酋国际航空货运部副总裁彼得·塞格利先生接受了记者的采访.     

承载友谊收获希望--柳林海轮首航美国西雅图港25周年庆祝活动纪实

2004年4月19日,正值中美两国第三个双边海运协定即将正式生效和实施之际,中国远洋运输集团与西雅图港务局共同在美国西部美丽的港口城市--西雅图举行系列庆祝活动,纪念中远柳林海轮首航美国西雅图港25周年.     

Analysis of the accident of the MVNakhodka. Part 1. Estimation of wave loads

MVNakhodka collapsed and broke in two on January 2, 1997 in the Sea of Japan, giving rise to a serious and disastrous oil spill on the coastline of Japan. During the inquiry into the cause of the accident, one of the main tasks of the inquiry committee was to identify the external loads which made the ship structure collapse. Among the several possible scenarios for the accident, after careful examination, the wave loads in the heavy weather at the time of the accident were taken to be the most plausible cause. The results of that research are described in two papers, and the present paper deals with the way in which wave loads on theNakhodka at the moment of the accident were estimated. We first describe the details of the accident such as the location, the sea condition, the loading condition, and the ship's heading speed. Then the static loads resulting from the distribution of the cargo weight and the buoyancy are given to show that the static bending moment at the time of the accident caused extreme sagging. Next the wave loads in the irregular waves, calculated by the nonlinear time domain simulation program SRSLAM, are presented. It is shown that the bending moment in the waves reaches 1 087 800 KN^*m at maximum SS 6.9, which is where the hull girder collapse took place. It was concluded that the ship broke in two because the bending moment exceeded the hull girder strength which had been reduced due to corrosion, taking into account conclusions derived from the research dealing with the structural strength aspect. We also discuss the stochastic significance of the estimated value and nonlinear nature of the peak distribution, in addition to the effects of the ship speed and wave heading on the wave load estimation. This article is based on an article that appeared in Japanese in the Journal of the Society of Naval Architects of Japan, vol. 183 (1998).     

Analysis of the accident of the MVNakhodka. Part 2. Estimation of structural strength

In the early morning of January 2, 1997, a Russian tanker, the MVNakhodka, broke in two in the Sea of Japan. The fore part of the vessel drifted and was stranded on the coast of Japan, and the aft part sank. The coast of Japan was seriously polluted by spilled heavy oil. Following this disaster, the Japanese Government established a Committee for the Investigation of the Causes of the Casualty of theNakhodka. This paper deals with the structural strength of MVNakhodka at the time of the accident. First the structural characteristics of theNakhodka are described, and the reduction in thickness of the structural members are estimated based on the data measured on the fore part of the vessel which drifted ashose. Then the ultimate longitudinal strength of the hull girder at the time of the accident is evaluated by applying Smith's method, and the possibility of break-up collapse due to excess loads is discussed. The mechanism of fracture at the bottom plate is also discussed based on the observed fracture surfuce of the cross section. Finally an FEM (finite element method) simulation of the break-up of the hull girder is performed. It is shown that buckling/plastic collapse took place at the deck plate near Fr.153, which was followed by the successive buckling collapse of the side shell plate of the hull girder. Right after the collapse of the deck structure, the bottom plate fractured just in front of the transverse bulkhead at Fr.153. This article is based on an article that appeared in Japanese in the Journal of the Society of Naval Architects of Japan, vol. 183 (1998).     

美国路易斯安那州主要港口介绍

主要介绍美国路易斯安那州主要港口管理状况。     

美国航母编队队形与反潜能力分析

2003年,美国海军将航母战斗群改为航母打击群,编队构成也发生较大变化,执行具体任务时其编成也会有一定调整。本文分析美国航母编队的具体构成,研究在不同护卫兵力规模下,美国航母编队的队形,并分析各种队形设置的合理性。根据美国航母编队队形和各种反潜装备的作战性能参数,分析美国航母编队在远程、中程和近程反潜区的反潜模式和反潜能力。     

新中国第一艘万吨轮诞生记

1968年1月8日,新华社报道的一条消息让全中国人民为之振奋,由中国自行设计建造的第一艘万吨级远洋货轮,经国家船舶检验局技术鉴定验收合格.     

美国海岸警卫队小艇装备体系研究

小艇装备作为美国海岸警卫队的中坚力量发挥着重要作用。本文重点介绍美国海岸警卫队小艇装备的分类,分析标准艇和非标准艇的定义、技术特征和典型装备型号;围绕任务属性概述小艇装备的重要作用,归纳美国海岸警卫队小艇装备的特点。     

美国航母飞行甲板演变及设计思想研究

飞行甲板是航母舰载机起降、调运、保障、布列最重要的作业场所,其设计工作在航母总体设计中占有重要地位,很大程度上决定了舰载机出动回收保障能力和航母综合作战效能.本文针对美国海军二战后至今研制的5型航母,分析其飞行甲板布局演变过程,梳理总结美国航母飞行甲板设计思想和启示.