基于能量法的刚构桥合龙顶推位移计算方法

为进一步明确刚构桥合龙顶推过程中高桥墩的力学特征,文章根据最小势能原理,应用Rayleigh-Ritz法推导刚构桥合龙顶推位移计算公式,以某刚构桥合龙顶推施工过程为例,对Rayleigh-Ritz解析解进行对比分析,揭示参数变化对顶推位移影响规律,阐明Rayleigh-Ritz解析解与静定解之间的差异。研究结果表明：采用能量法计算的刚构桥合龙顶推位移计算结果与有限元法分析结果最大偏差为3.6%;由于重力二阶效应和墩顶偏心力矩对顶推位移的影响程度不同,Rayleigh-Ritz解析解与不考虑重力二阶效应结果较为吻合,静定解计算结果偏小;刚构桥墩高增大,Rayleigh-Ritz解析解与不考虑重力二阶效应结果、静定解的偏差均变大,最大分别为15.1%、29.8%。重力二阶效应和墩顶偏心力矩对墩高变化的敏感性不同,一般刚构桥不能忽视墩顶偏心力矩,超高桥墩顶推位移计算需重点考虑重力二阶效应的影响。     

阜阳市泉河大桥110m跨悬浇合龙施工质量控制

文章从监理质量控制的角度,结合阜阳市泉河大桥110 m跨悬浇合龙段合龙质量要求,详细阐述了悬浇合龙段合龙施工中顶推、骨架安装、混凝土浇筑等关键环节质量控制的要点及方法.     

矮墩连续刚构桥合龙顶推力研究

连续刚构桥中跨合龙时需要通过施加顶推力对结构的内力状态进行预调整.结合工程实例,讨论了柔性基础矮墩连续刚构桥合龙顶推力的确定方法,分析了顶推前后结构的内力与变形规律,得出施加顶推力来主动调整内力可有效地改善桥梁结构的受力和使用状态,提高桥梁的耐久性.     

高桩承台柔性基础连续刚构桥合龙顶推力研究

连续刚构桥中跨合龙时通常通过施加顶推力对结构内力进行主动调整。该文结合工程实例,讨论了具有高桩承台柔性基础的连续刚构桥合龙时顶推力的确定方法,通过对比分析顶推前后结构的内力与变形规律,论证了通过施加顶推力来主动调整内力可有效地改善桥梁结构的受力和使用状态,提高桥梁的耐久性。     

苏通大桥主桥上部结构施工及控制技术研究

苏通大桥是目前世界上已建成的最大跨径斜拉桥,其主桥上部结构施工,主要包括边跨辅助跨以及索塔区大块梁段安装,标准梁段安装以及中跨合龙几个阶段。其中大块梁段采用浮吊整体吊装,标准梁段采用桥面双吊机系统进行吊装,中跨合龙采取顶推辅助合龙方法。同时在施工过程中采用了全过程自适应几何控制方法,通过全过程精确控制结构构件的无应力尺寸与形状,以及实现控制系统和被控制系统相适应来达到控制桥梁结构最终线形和内力的目标。为了解决长悬臂主梁风致振动条件下的测量问题,采用了包括基于GPS和基于全站仪的两种动态几何监测系统。对上部     

高墩大跨连续刚构桥中跨合龙顶推力计算方法

 为合理确定高墩大跨连续刚构桥中跨合龙的顶推力,基于力法原理提出一种适用于单柱式墩连续刚构桥先边跨后中跨合龙的顶推力解析计算方法。以某三跨连续刚构桥施工工程为例,应用解析法计算先边跨后中跨合龙的顶推位移和顶推力,同时利用数值模拟法建立有限元模型,以消除5 年收缩徐变及合龙温差引起的墩顶水平位移为原则进行计算比较,并以工程实测结果进行验证。结果显示,解析法计算值、有限元计算值和实测值三者之间误差很小,解析法与有限元法计算误差小于10%,表明解析法具有较高的计算精度,能满足实际工程要求。     

对箱梁顶推施工工艺的探讨

在箱梁顶推施工过程中，施工的工艺控制最为重要，它将直接影响桥梁的质量及安全。本文针对这一问题，提出了顶推法施丁的技术原理及方法，并对顶推施工的关键技术进行了探讨。     

斜连续梁桥顶推施工控制

文章以采用顶推法施工的张家界澧水大桥为背景，分析了斜度在顶推阶段对土梁内力的影响，进行了顶推仿真计算，并具体阐述施工控制的实施与成果，为同类型的预应力混凝土斜连续梁桥的顶推施工监控提供参考。     

多跨连续刚构桥同步合龙顶推优化施工技术

连续刚构桥以其跨度大、施工便捷、节约成本、适应性强、抗震性好等优点在交通领域应用广泛.铜黄高速公路沮河特大桥总长978m,桥面到沟壑底部最低处的高差为181m,总跨度650m,采用薄壁轻型高墩,是当时中国西部最高最大跨度的连续刚构桥.通过对大桥主梁的结构尺寸、竖向预应力筋布置、合龙顺序、跨中预拱度等关键设计进行分析,并用桥梁博士(Doc-tor Bradge)软件进行计算,验证多跨同步顶推一次整体合龙技术的合理性,并对边跨合龙段、次中跨、中跨现浇段模板、钢筋安装、配重设置、顶推、混凝土浇筑、养护等关键工序进行了总结.     

黄冈公铁两用长江大桥钢桁梁主跨主动快速合龙施工技术研究

黄冈公铁两用长江大桥主桥为双塔双索面斜主桁双层桥面大跨度钢桁梁斜拉桥,主跨567m、斜主桁倾斜角度20.3532°,均为世界同类型桥梁之最,主梁设计为上宽下窄的倒梯形截面,全桥设1个合龙口,采用70t全回转架梁吊机散拼架设。发明了一种纵向大位移顶推装置用于满足主动合龙时主梁大范围纵移的需要,通过敏感性分析深入研究各项合龙调整措施的效果及规律,并选出满足主动快速合龙要求的措施去完成主梁合龙,最终只用5h就完成了主桁4根弦杆同步高精度合龙,成桥线形流畅,各项指标完全满足设计要求。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that