建筑结构设计对张拉控制应力和预应力损失的要求

在施工阶段,张拉控制应力就是预应力钢筋所受的最大应力。引起预应力损失的因素很多,而且相互影响、相互依存,建筑结构设计对张拉控制应力和预应力损失具有一定的要求,要精确计算和确定预应力损失是一项非常复杂的工作。     

桩基工程施工质量控制

静压预制桩是处理软弱地基的有效方法之一,本工程采用静压预制桩的实例,通过计算和分析,来提出有效控制本桩基工程施工质量的措施,为以后本地区或类似地质条件下的地基加固提供借鉴。     

预应力混凝土转换梁设计与施工

通过工程实例,介绍运用中国建筑科学研究院编制的结构设计软件PKPM计算预应力混凝土转换梁的方法,绘制了施工图,并讨论了预应力混凝土转换梁施工中应注意的关键问题.     

Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory

Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows： the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the ttiird was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.     

连续箱梁桥拓宽拼接方式的分析

基于高速公路上混凝土连续箱梁桥的不同特点,结合拓宽工程实践,总结了现有刚接及铰接方式的适用范围及具体构造,然后针对错孔布置桥梁拼接受力复杂、三向预应力箱梁拼接不能破坏横向预应力以及大跨径桥梁拼接等工程难题,提出了箱梁间不连接或弱连接的构造设想,以期对同类工程有参考价值。     

预应力混凝土空心板产品质量通病

预应力混凝土空心板在我国城乡建设中广泛使用,极大地满足了我国生产建设需要.一些生产者为谋取利益,降低生产标准、违反质量规范,制造了大量不符合质量要求的产品,给人民的生命、财产安全带来了严重隐患.笔者根据多年工作经验,总结出该产品的质量通病,并提出了应对措施.     

工程静压桩桩端扩张压力评价

为研究工程桩端扩张压力,对现有计算方法进行了改进。文章根据静压桩贯入机理,分析了静压桩的贯桩过程;并在模拟桩体贯入过程的基础上,建立了基于半无限圆孔扩张的压桩静力平衡方程,求得了弹性条件下桩端扩张压力的理论解答,同时进一步分析了桩端扩张压力与压入深度的关系。     

由电气软故障导致的设备停机检修一例

本文主要介绍了由比例阀放大器电气软故障所导致的的KW静压造型线无法正常生产问题,介绍了设备检修的主要过程,以及最终故障原因和维修方法。     

浅谈预应力砼现浇连续箱梁施工技术

结合金山大道快速干道立交桥的工程概况,从地基处理、支架搭设与预压、模板、支座安装、钢筋与波纹管制作与安装、砼浇筑与养护、模板与支架拆除、张拉钢绞线、真空灌浆与封锚、卸落支架等方面就预应力砼现浇连续箱梁的施工工艺作了阐述,并总结了现浇箱梁施工控制要点,为类似条件的工程施工提供了借鉴.