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1.
施随着经济和科学技术的迅速发展,为了适应现公路运输的要求,公路桥梁建设的力度在不断加大,T梁桥型在公路建设中已经得到普遍应用.本文简单阐述了中小跨径T梁预制的施工顺序,包括台座设置、模板制作与安装、钢筋加工与安装、混凝土浇筑与养护、预应力张拉、孔道压浆及封端等施工过程.  相似文献   

2.
根据桥梁和挂篮的结构特点,论述了挂篮在施工过程中的安装方法和安装后的加载试验过程.  相似文献   

3.
《科技风》2016,(22)
在连续刚构0号段施工成熟方法中,通常采用支架法施工和堆载法压或承台中预埋钢绞线反拉预压的施工方法,用堆载法预压支架优点是模拟受力情况较为逼真,但存在耗费材料多、加载时间长、加载墩位难以精确控制的问题;采用承台预埋钢绞线千斤顶反力预压施工方法,存在钢绞线使用量较大,费用高,成本大的缺点。为了克服这些缺点,结合现场实际情况,经多方咨询和论证,采用墩顶固定贝雷梁反力架,托架上千斤顶顶升贝雷梁反力预压0#块托架的预压方法,将面荷载模拟成等效的多点集中荷载。采用此方法具有材料用量少、受力明确、容易控制、预压时间短、施工方便、费用节省等优点。  相似文献   

4.
混凝土结构浇筑完毕经过一段时间后,混凝土强度达到一定要求时可进行模板拆除,达到模板周转使用的目的。在当今的建筑施工技术中,模板的安装和拆除都已成为建筑工程施工的主要手段和方法,其施工工艺和技术已被广泛应用。本文现就模板拆除施工技术进行简要分析。  相似文献   

5.
龙冈互通区A匝道桥为十孔一联连续箱梁,在处理后的地基上搭设满堂式钢管支架施工,并对地基处理、支架搭设、模板安装及支架拆除等各个施工环节进行细致设计,保证了工程质量及施工安全。  相似文献   

6.
建筑行业的飞速发展带来了施工技术的不断创新,楼虽然越盖越高,质量却无法得到保证。人们对建筑的安全也产生了隐忧。如今建筑的结构是以混凝土剪力墙为主。在施工中混凝土模板的安装工艺与安装质量与整个建筑的安全稳定有着重大关系。本文将探讨建筑施工中模板的安装工艺以及对施工质量进行控制的方法,以提高整个建筑工程的质量。  相似文献   

7.
《科技风》2016,(7)
通过黄家岭隧道洞内的二衬、仰拱快速施工技术的应用,介绍了隧道二衬、仰拱端头模板的加工与现场安装的施工方法,分析了二衬、仰拱端头模板在长大单线隧道的应用价值,阐述了二衬、仰拱端头模板在长大单线隧道中的使用,能有效的控制二衬、仰拱的施工质量。以黄家岭隧道为例,表述了二衬、仰拱端头模板的加工与安装的一般施工工艺、方法。  相似文献   

8.
结合工程实例,介绍分析高层建筑高空及弧悬挑结构施工技术难点,对其模板支撑体系的造型及结构计算进行了详细阐述,并从模板设计安装混凝土浇捣等方面进行了深入分析和总结。  相似文献   

9.
在西藏地区为有效的降低施工强度,达到快速、高效且保证混凝土施工外观质量高的目的,现提出一种塑钢模板的施工方案,通过对塑钢模板的制作要求、面板处理、重量控制、模板拼接装置设计、模板安装及加固、模板的拆除及修复措施等几方面研究和改进,模板重量降低极大减轻了工人作业强度并且减少辅助机械使用数量,模板的拼接和加固技术促进了模板的施工速度。模板面板采用高分子材料减少模板的清理,基本不用脱模剂就可以保证混凝土结构的外观质量,达到混凝土结构表面平整、光滑、光亮的效果。此外模板为可修复再利用、可回收再利用材料,保证了模板循环次数,模板再回收降低了施工成本。经施工效果分析,塑钢模板可循环使用30次,计算其经济效果显著,前期购置成本投入与传统钢模板相当,后期的施工经济性显著优于钢模板,而施工效果显著优于木模。  相似文献   

10.
结合工程实例,介绍分析了高层建筑高空及弧悬挑结构施工技术难点,对其模板支撑体系的造型及结构计算进行了详细阐述,并从模板设计安装混凝土浇捣等方面进行了深入探讨和总结。  相似文献   

11.
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.  相似文献   

12.
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.  相似文献   

13.
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.  相似文献   

14.
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.  相似文献   

15.
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.  相似文献   

16.
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China's science enterprise by making S&T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party's Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.  相似文献   

17.
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."  相似文献   

18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.  相似文献   

19.
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment.  相似文献   

20.
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.  相似文献   

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