预应力梁桥齿板锚固区配筋设计新方法

预应力混凝土梁桥的齿板锚固区,由于存在着几何形体上的突变,集中锚固力的作用以及预应力钢束局部弯曲引起的径向力作用,易产生开裂甚至剥落破坏,因此齿板锚固区的抗裂配筋设计十分重要。以7种典型局部作用效应刻画齿板锚固区内拉应力的集中分布特征,并在此基础上形成了齿板锚固区拉压杆模型,初步形成预应力混凝土梁桥的抗裂钢筋设计新方法。     

后张锚固区抗劈裂配筋设计方法研究

根据主应力迹线构建出后张锚固区的拉压杆模型,在此基础上,利用拉压杆模型中节点力的平衡条件计算劈裂力大小,通过对比拉压杆模型法、美国AASHTO规范公式、以及有限元结果,表明拉压杆模型法考虑的影响因素更为全面,计算精度更高。最后,通过实例示范了抗劈裂钢筋的配筋设计方法。     

拉压杆模型在混凝土梁桥中应用与研究进展

在介绍拉压杆模型的概念和构形的基础上，讨论了混凝土梁桥中的常见D区和拉压杆模型的应用原理和构建准则，给出了应用该方法进行结构D区设计的一般步骤，作为示例，应用拉压杆模型方法并参照美国AASHTO LRFD(2004)规范，对一较典型的预应力齿板锚固区进行了配筋设计。阐述了拉压杆模型的起源、研究现状与进展，概括分析了当前国际上的研究动态和有待深化研究的方向。     

预应力混凝土T梁桥端部锚固区拉压杆模型及配筋设计

根据有限元应力分析结果,抽象出力流传递路径,提出了T梁端部锚固区拉压杆模型的构形方法.通过对劈裂应力的数值积分,计算合力作用点位置,并将其作为拉杆位置确定的依据.分析表明,由于T梁端部锚固力的合力对截面形心的偏心距不大,劈裂应力合力作用点至锚固端的距离与梁高的比值,基本不受锚下预加力大小、梁高以及翼板宽度变化的影响,大小稳定在0.67~0.69之内.最后,应用该构形方法,得到了跨度为20~50m的T梁端部锚固区拉压杆模型,将由拉压杆模型计算出的劈裂力大小与精细化有限元分析结果进行了比较,其比值分布在1.16~1.34范围之内,由此可见,由拉压杆模型给出的劈裂力计算值与有限元分析结果之间相差不大,且偏于安全.     

平武枢纽D匝道1号桥钢混组合梁变更现浇预应力箱梁方案设计

该文分别采用Midas Civil Designer和Ansys软件对桥梁结构进行计算,并以《公路桥涵设计通用规范》（JTG D60-2015）和《公路钢筋混凝土及预应力混凝土桥涵设计规范》（JTG 3362-2018）为标准。Midas Civil Designer软件采用梁格法离散模型,横向通过横向联系及虚拟边横梁连接,车道荷载加载与横向联系上可按实际模拟。该文主要对平武枢纽D匝道1号桥钢混组合梁变更现浇预应力箱梁方案设计进行简单的阐述。     

公路桥梁规范中温度自应力计算方法误差的理论分析

基于弹性力学中三个不同方向的应力通过泊松比耦合在一起的性质,理论分析《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 3362—2018)及《公路桥涵设计通用规范》(JTG D60—2015)中规定的桥梁结构的温度自应力简化计算方法中的误差,并基于热弹性力学中温度应力的Duhamel相似定理,分析温度荷载作用于桥梁结构中的作用方式,即温度自应力的荷载模式,并基于这种思路分析桥梁规范中对温度荷载形式简化的合理性,进一步分析这种简化所可能导致的误差及今后可能的研究方向与解决方案。     

先简支后连续混凝土梁负弯矩区UHPC “T形”湿接缝试验研究

为了提高普通混凝土连续梁负弯矩区湿接缝的抗裂性能,简化施工工艺,提出了混凝土梁桥负弯矩区UHPC新型湿接缝方案.以某跨径为30 m的普通混凝土连续梁桥为背景,根据法国UHPC结构设计规程和《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG3362-2018)对该桥进行正常使用极限状态下的配筋设计,并参照配筋设计结果对UHPC新型湿接缝构造进行1∶2缩尺模型试验研究.试验结果表明:取消负弯矩区预应力束、取消焊接的负弯矩区UHPC新型湿接缝方案的抗裂性能和承载能力均满足工程要求,且试验值与数值模拟值拟合良好;UHPC的引入能有效限制普通混凝土的裂缝宽度,显著提高普通混凝土截面的刚度,改善混凝土连续梁跨中区的内力及竖向挠度的重分布现象.与不考虑负弯矩预应力束的传统湿接缝构造相比,UHPC新型接缝构造能降低混凝土连续梁内力及跨中竖向挠度的重分布系数至其30％～50％.参数分析表明:对于负弯矩区采用UHPC新型湿接缝构造的混凝土连续梁桥,UHPC沿纵桥向的长度宜取0.27倍计算跨径,负弯矩区纵向受拉主筋直径可统一为20 mm,UHPC层的厚度取60 mm即可.     

伸缩装置UHPC锚固构造设计与静力性能研究

为综合解决桥梁伸缩缝锚固区混凝土易破损及预埋件焊接工艺繁琐的难题,提出两种现场零焊接UHPC（Ultra-high Performance Concrete）伸缩缝锚固接头优化构造方案：优化构造1中锚板一侧布置锚筋另一侧布置短栓钉;优化构造2中锚板两侧均布置短栓钉,且型钢侧向加设长栓钉;两种优化构造中锚板与预埋钢筋均错开布置,锚固区浇筑UHPC. 新方案简化了现场施工操作,使伸缩装置安装质量可视化. 为探究新方案的锚固性能,并与传统焊接形式进行对比,即锚板一侧布置锚筋另一侧与预埋钢筋现场焊接,锚固区浇筑SFRC（Steel Fiber Reinforced Concrete）,对8个1∶1伸缩缝接头模型进行锚固性能静力拔出试验研究. 结果表明：两种优化伸缩缝接头构造的结构刚度、强度、抗裂性能及锚固性能均有明显提升,优化构造1、2的初裂荷载为传统焊接构造的2.2倍,极限承载能力分别为传统焊接构造的1.38倍和2.33倍;UHPC表面裂缝分布相对集中,数量少且细,而SFRC表面裂缝分布较为分散,数量多且宽;优化构造2中长栓钉的加设有效限制了界面裂缝的发展. 对比研究表明,两种优化方案提高了伸缩装置的受力性能和锚固性能,现场零焊接、安装容差性高,可为桥梁伸缩缝设计提供参考.     

自锚式悬索桥主缆锚固区空间应力分析

目的对典型的锚固区局部节段进行分析,以解决自锚式悬索桥主缆锚固区结构复杂,平面杆系程序无法把握锚固区复杂受力状态的问题,为桥梁设计和施工提供参考依据.方法运用MIDAS/FEA建立浑河景观桥锚固区局部有限元模型,分析最不利索力设计值下的局部应力状态及不同荷载下的极限承载力.结果锚固区在主缆索力T=50 000 kN作用下,产生的最大位移为4.91 mm;锚垫板的索孔周围的von Mises应力在110 MPa左右.随着荷载的增加,锚固区von Mises应力不断增大.当索力为设计荷载的3.5倍时,锚固区各板件的应力均达到了468 MPa以上,位移最大值为24 mm.结论主缆锚固区各构件的刚度和强度均满足要求,锚固区的极限承载力为设计荷载的3.5倍,结构的安全系数较高.     

公路桥涵新旧设计规范的安全比较探讨

随着工程经验的总结和科学理论的发展,公路桥涵的设计规范一直处于不断的完善修改之中,本文以预应力板梁和普通钢筋混凝土梁为例,通过对结构中配筋的不同、预应力损失的不同、抗裂验算要求等方面的对比分析,对公路桥涵新、旧设计规范的安全进行了比较探讨,从而促进新规范的推广使用。     

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.     

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.     

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.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.