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41.
连续刚构0#块处于墩梁固结处,该梁段构造复杂,内有大量的预应力束通过。为揭示其在各种不利工况下的空间应力分布情况,需建立相应的空间有限元模型进行分析。文章以一座连续刚构桥为工程背景,运用ANSYS有限元软件对0#块进行局部应力分析,结果表明0#块局部位置应力分布较复杂,应进行钢筋补强。  相似文献   
42.
水泥消石灰对OGFC路用性能的影响   总被引:1,自引:0,他引:1  
通过在OGFC混合料中加入水泥或消石灰的试验,研究水泥和消石灰取代部分或全部矿粉后对OGFC 混合料路用性能的影响,并寻求最佳掺量.试验结果表明:在OGFC混合料中加入了水泥或消石灰后,对OGFC的马歇尔稳定性、水稳定性和高温稳定性均有明显的改善作用,水泥的最佳掺量为矿料总质量的2.8%,消石灰的最佳掺量为矿料总质量的4.2%.  相似文献   
43.
依托新建北京至张家口高速铁路延庆下行联络线跨大浮坨村烽火台特大桥主跨连续梁0^#段工程施工,详细地介绍了连续梁0^#段预制完成后吊装就位的施工技术,并制定了安装过程施工质量和安全控制措施。采用该技术,连续梁0^#段和桥梁主墩可同时施工,不仅能保证工程施工质量和工期,而且在北方寒冷地区高空中无法实现冬施措施的项目中具有很强的推广价值。通过新建京张高速铁路桥梁工程的连续梁工程的快速施工,验证了该技术的可行性。  相似文献   
44.
荷麻溪特大桥主梁特大型0号块采用贝雷架作支架、水平分三层浇筑等施工技术,采用超宽三角斜拉式后支点挂篮现浇部分斜拉桥大型箱梁施工技术,以及斜拉索采用环氧涂层钢绞线成品索,工厂加工成品,现场整束安装整束悬浮式张拉技术。  相似文献   
45.
本文简略介绍了抗横倾系统的功能,对其系统组成和工作原理进行详尽的说明,并介绍我厂对抗横倾‘0’位的检验方法。  相似文献   
46.
An experimental sediment dumping was carried out in the southern part of the Mecklenburg Bight in June 2001. Foraminiferans and ostracods from superficial sandy sediment were studied in a time series from before dumping until March 2004 in order to assess changes in associations and recolonization patterns of both groups. Additionally, an area sampling covering the dumping site and its surroundings from 15.5 to 20.7 m water depth made it possible to compare associations inside and outside the dumping area as well as the water depth dependent distribution of foraminiferans and ostracods. Salinity values vary within the high alpha-mesohaline and low polyhaline range. The dominating species are Ammotium cassis (Foraminifera) and Sarsicytheridea bradii (Ostracoda). The diversity is low (Fisher alpha index from 0.4 to 3.2 for foraminiferans and 1.0 to 2.5 for ostracods), but higher within the dumping site samples. These higher values are explainable by input of allochthonous tests and valves representing additional species. After the sediment dumping it took two and a half years to re-establish the total foraminiferan association and the total foraminifer/ostracod ratio within the dumping site. Total foraminiferan abundance increases remarkably with water depth (mean 83 tests in 100 ml) driven by higher nutrient availability and more suitable salinity and temperature values within the zone of the oscillating halocline. The distribution of shallow water species such as Cribroelphidium excavatum, Eucythere argus and Hirschmannia viridis, within the transient water layer A. cassis, Nodulina dentaliniformis, S. bradii and Palmoconcha laevata and below Eggerella scabra indicate the depth position of the halocline. Water depth and sediment dumping influence are the main driving factors for the distribution of foraminifer and ostracod associations within the study area. However, a significant sedimentological difference between samples inside and outside the dumping area is not recognizable.  相似文献   
47.
The key features of the western Galician shelf hydrography and dynamics are analyzed on a solid statistical and experimental basis. The results allowed us to gather together information dispersed in previous oceanographic works of the region. Empirical orthogonal functions analysis and a canonical correlation analysis were applied to a high-resolution dataset collected from 47 surveys done on a weekly frequency from May 2001 to May 2002. The main results of these analyses are summarized bellow. Salinity, temperature and the meridional component of the residual current are correlated with the relevant local forcings (the meridional coastal wind component and the continental run-off) and with a remote forcing (the meridional temperature gradient at latitude 37°N). About 80% of the salinity and temperature total variability over the shelf, and 37% of the residual meridional current total variability are explained by two EOFs for each variable. Up to 22% of the temperature total variability and 14% of the residual meridional current total variability is devoted to the set up of cross-shore gradients of the thermohaline properties caused by the wind-induced Ekman transport. Up to 11% and 10%, respectively, is related to the variability of the meridional temperature gradient at the Western Iberian Winter Front. About 30% of the temperature total variability can be explained by the development and erosion of the seasonal thermocline and by the seasonal variability of the thermohaline properties of the central waters. This thermocline presented unexpected low salinity values due to the trapping during spring and summer of the high continental inputs from the River Miño recorded in 2001. The low salinity plumes can be traced on the Galician shelf during almost all the annual cycle; they tend to be extended throughout the entire water column under downwelling conditions and concentrate in the surface layer when upwelling favourable winds blow. Our evidences point to the meridional temperature gradient acting as an important controlling factor of the central waters thermohaline properties and in the development and decay of the Iberian Poleward Current.  相似文献   
48.
49.
现有工程建设大多面临着直接、机械式的制约后续工程建设用地、后续工程建设持续发展困难的问题。文中从虚工作既不占用时间、也不占用社会生活环节的资源,但它具有时间指标、时间属性虚资源这个角度.提出采用无机动时差的双代号网络进度计划图所实现的“虚工作”的虚特性,解决占地、后续工程持续发展困难等问题的方法。它从虚工作(具有时间属性)的维系客观背景所带来的新的工程客观条件和合乎社会的时代步伐、节拍基础上,解决了工程占地、资源重复利用方面的困扰。它能够满足地区或国家建设领域的稳定、安全发展需要。  相似文献   
50.
武汉西四环汉江特大桥主桥为(77+100+360+100+77)m预应力混凝土梁斜拉桥,主梁为π形结构,两边为单箱双室、中间为纵横梁加桥面板结构形式。主梁0号块宽44m、长22m,采用钢管桩贝雷梁支架现浇施工。支架由底模系统、横梁(贝雷梁)、桩顶分配梁、砂筒、钢管支架组成,支架施工完后采用反力架预压钢管桩,边箱室顶板底模采用透水模板布施工。通过混凝土配合比优化,配制高耐久性、稳定性的C55高性能混凝土,并采用天泵和地泵从两个方向分层浇筑,桥面纵、横坡采用提浆整平机控制。在0号块混凝土强度成长期预张拉横向预应力,纵向预应力待1号和1′号块施工完采用连接器连接构成整束一次性张拉;预应力采用智能张拉系统张拉、智能压浆系统压浆。实践表明,该桥采用该施工技术成功克服了支架不均匀沉降,有效控制了裂纹的产生,保证了主梁0号块的施工质量与施工安全。  相似文献   
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