粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅰ:双向拟静力试验

设计制作了11个钢筋混凝土箱型截面桥墩缩尺模型,对其进行了粘钢加固后的双向拟静力试验,分析了加固桥墩的荷载-位移滞回曲线、骨架曲线、延性能力、刚度退化和耗能能力等.结果表明,加固墩柱均发生以弯曲破坏为主的延性破坏,破坏塑性铰由未加固时的墩底上移至加固钢板位置的上边缘,加固后墩柱各项抗震性能良好,表明粘钢加固损伤桥墩是一种有效的抗震加固方式.墩柱强轴方向的滞回环饱满,承载力和刚度较大;弱轴方向的滞回环捏缩效应显著,耗能能力较强.初始损伤程度仅对粘钢加固墩柱的刚度退化及耗能能力具有一定影响.随着轴压比的增大,加固试件的承载力变大,极限变形能力降低,延性能力和耗能能力均增强.而随着长细比的减小,加固试件的承载力变大,极限变形能力降低,刚度退化情况严重.     

基于延性性能圆形钢桥墩內填混凝土补强填充高度的简易计算方法

目的探明圆形钢桥墩内填混凝土补强填充高度的计算方法及长细比和钢管径厚比参数对圆形截面钢桥墩承载力、延性等抗震性能的影响.方法在确定有限元分析与试验结果吻合的基础上,采用ABAQUS有限元软件对9组60个不同填充混凝土桥墩模型进行非线性数值模拟分析.结果与空钢管桥墩柱相比,部分填充混凝土圆形钢桥墩具有良好的抗震性能.随着混凝土填充率的增加,该类桥墩的延性和承载力均有所提高,超过最适填充率后,持续增加混凝土填充率,模型的承载力提高但延性下降.结论拟合出的混凝土填充率、承载力及延性与长细比和径厚比的关系公式为圆形钢桥墩内填混凝土补强填充高度的设计提供了依据.     

外包钢板对钢筋混凝土桥墩抗震性能影响的试验研究

分别进行了普通钢筋混凝土桥墩和外包钢板混凝土桥墩的拟静力试验,得到了两类桥墩的滞回曲线、骨架曲线,对比分析了其承载力、延性系数、耗能能力及残余位移,研究了外包钢板对提高钢筋混凝土桥墩抗震性能的效果.结果表明:外包钢板桥墩的屈服荷载与位移、峰值荷载与极限荷载均大于普通钢筋混凝土桥墩的相应值,外包钢板能够提高桥墩的承载力和...     

偏心受压部分填充混凝土圆形钢桥墩横桥方向作用下拟静力试验

目的研究偏心受压及横桥方向往复荷载作用下部分填充混凝土圆形钢桥墩的力学性能.方法在径厚比、长细比等参数相同的条件下,竖向偏心荷载的偏心率为0.1和0.2时,对4个圆形截面部分填充混凝土钢桥墩试件进行试验.分析偏心受压及横桥向荷载作用下部分填充混凝土钢桥墩柱试件试验结果.结果竖向偏心荷载的存在改变了试件的受力性能.当试件的径厚比、长细比参数相同时,偏心率对钢管柱的承载能力影响比较明显.偏心率越大,桥墩的初始水平位移也随着增加.而偏心荷载的存在使得试件在偏心侧的承载力降低了7%~15%,另一侧加强了10%~18%,且偏心率越大,该现象越明显.结论内填混凝土对钢桥墩柱试件的承载力和延性性能有很好地补强效果;而竖向偏心荷载的存在使得试件在偏心侧的承载力降低,另一侧加强.     

特征参数对高速铁路桥墩抗剪性能的影响研究

为了研究特征参数对高铁桥墩抗剪性能的影响特征及规律,以PEER数据库中墩柱为原型,基于OpenSEES平台分别建立了考虑弯剪耦合效应和弹性剪切效应的精细化墩柱模型.经对比验证发现:对于可能发生脆性破坏的墩柱,墩柱的弯剪耦合效应对模拟结果有决定性影响.以京沪高铁某连续梁桥桥墩为对象,建立考虑弯剪耦合效应的精细化分析模型,分析了特征参数对高铁桥墩抗剪性能的影响,结果表明:纵筋率对高铁桥墩抗剪承载力的影响最大,剪跨比次之,轴压比的影响最小;纵筋率的增大使桥墩抗剪承载力最大增加了292%,延性水平降低;随着轴压比的提高,桥墩抗剪承载力有所增大,最高增幅为50%;增大剪跨比可显著提高桥墩延性,但会使抗剪承载力显著降低.     

锈蚀钢筋混凝土墩柱的双向拟静力试验

为探讨钢筋锈蚀对混凝土桥墩抗震性能的影响,对2组共10个具有不同锈蚀率的钢筋混凝土墩柱模型进行双向拟静力试验,得到在两个不同轴压比下、钢筋不同腐蚀程度时的滞回曲线.分析了钢筋锈蚀率和轴压比对墩柱模型承载力、刚度、位移延性和滞回耗能等的影响,给出墩柱模型的骨架曲线和刚度退化曲线.结果表明,钢筋锈蚀在一定程度上可改变钢筋混凝土墩柱的破坏形态,尤其是在较大的轴压比下;钢筋锈蚀对钢筋混凝土墩柱的水平承载力和位移延性均有较大影响.     

钢筋混凝土十字形截面柱曲率延性的研究(英文)

钢筋混凝土十字形截面柱在不同荷载角下的力学性能差别很大,在工程实践中应给予足够的重视.在充分考虑荷载角对十字形截面柱曲率延性影响的基础上,提出两种曲率延性的概念.通过对10 800根十字形截面柱的曲率延性进行计算机模拟计算,分析了中和轴角、轴压比、混凝土强度、纵筋强度、体积配箍率、肢高肢厚比以及不等肢长等各种参数对其曲率延性影响,得出各因素对曲率延性的影响规律,建立了中和轴角曲率延性和荷载轴角曲率延性的计算公式,成果可供结构设计和工程实践参考.     

高阻尼混凝土钢板暗支撑双肢剪力墙数值分析

在试验研究的基础上,用非线性有限元分析软件MSC.Marc对高阻尼混凝土带钢板暗支撑双肢剪力墙进行了低周反复荷载下的数值模拟,并分析了轴压比、配钢率、高宽比和连梁刚度等对高阻尼混凝土带钢板暗支撑双肢剪力墙承载力和变形性能的影响规律.分析结果表明,数值模拟结果和试验结果吻合较好,当轴压比大于0.4时,高阻尼混凝土钢板暗支撑双肢剪力墙的延性显著下降,相对暗支撑配钢率为0.96~6.73时,能较好地改善双肢剪力墙的极限承载力.连梁跨高比、高宽比主要影响双肢剪力墙的承载力和变形性能.研究结果对高阻尼混凝土暗支撑双肢剪力墙的地震弹塑性计算具有一定的参考价值.     

竖向偏心部分填充混凝土圆形钢桥墩的抗震性能

目的探析竖向偏心受压部分填充混凝土圆形钢桥墩柱在横桥方向往复荷载作用下的抗震性能.方法以城市高架桥倒L型桥墩为研究对象,利用有限元分析软件ABAQUS建立了该类钢桥墩的有限元分析简化模型,根据计算得出的力与位移(H-δ)滞回曲线结果,对其在竖向偏心荷载及横桥方向往复荷载作用下的柱两侧水平承载力及无偏心和偏心桥墩柱之间的承载力关系进行了研究.钢桥墩柱的长细比参数取0.2、0.3和0.4,钢管部分截面径厚比参数取0.07、0.08和0.09,竖向荷载的偏心率e则取0、0.1、0.15和0.2.结果部分填充混凝土钢桥墩在偏心一侧的水平承载力降低,相反在另一侧的水平承载力则得到增强,呈明显的不对称性,且随着偏心率的增加,抗震性能降低.拟合得出一个关于无偏心受压钢桥墩柱与偏心受压钢桥墩柱之间H-δ滞回曲线关系的经验公式.结论经验公式计算得出的骨架曲线和滞回曲线与有限元分析直接得到的骨架曲线和滞回曲线结果无论在弹性阶段还是在塑性阶段吻合性均较好,经验公式的有效性得到验证,该公式将为偏心受压部分填充混凝土圆形钢桥墩横桥方向的抗震性能设计提供理论依据.     

钢筋混凝土异形柱非线性全过程分析方法研究

为了研究十字形柱的抗弯承载力和曲率延性比的一些变化规律,根据双向偏压作用下钢筋混凝土异形柱的工作基理,以平截面假定为基础,选用了合理的钢筋和混凝土本构关系模型.提出了基于条带划分法的非线性全过程分析方法,以十字形柱为例进行了分析计算,并通过正交试验分析了混凝土强度、体积配箍率、轴压比和荷载角对异形柱截面抗弯承载力及截面曲率延性比的影响.同时,本方法亦适用于其他钢筋混凝土异形截面柱在双向偏压作用下的非线性全过程分析,也可用于工程实际.     

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