共查询到10条相似文献，搜索用时 328 毫秒
1.
软木伸缩缝填料用作水电站钢蜗壳垫层材料的探讨 总被引：1，自引：0，他引：1
就软木伸缩缝填料用作水电站钢蜗壳垫层材料进行探讨,分析其作用和效果;介绍软木的特性以及软木伸缩缝填料的生产工艺;并对几种常用的垫层材料进行试验对比分析.试验结果表明,软木伸缩缝填料适合作大、中型水电站钢蜗壳外包垫层的材料. 相似文献
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本文通过对几种桥梁伸缩缝的测试,并分析了测试的数据,认为最新生产的江苏毛勒伸缩缝既可满足桥梁梁端变形需要,又可起到防水作用,同时还具有良好的舒适性和耐用性。 相似文献
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Anna Pousette 《Journal of Wood Science》2006,52(4):358-362
Joints in traditional wooden stairs can be constructed in many different ways. Connections between tread and string are commonly
made with tenons and screw joints. It is often hard to know which joint rigidity should be used in calculations. To study
this type of stair, a total of 12 small straight stairs with three steps each were tested. The stairs were loaded and the
deformation was measured. Modeling of the stairs with a finite element program was also performed, using linear elastic models
in the analysis. The conclusion derived from the study is that the tested tread-to-string connections are not very rigid.
Tolerances and accuracy of manufacture of the stair parts are important for the behavior of the joints. Comprehensive knowledge
about stair joints can be used for development of new cost-effective and reliable design tools for stairs. In a computer program
for stair design based on beam elements, the treads in this type of staircase should, according to this study, preferably
be calculated as being hinged to the string, or else the rigidity of the joint should be a function of joint parameters. 相似文献
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旧水泥混凝土路面加铺改造前,应对原路面进行综合处治,包括换板、裂缝修补、更换填缝料等,本文就某二级公路水泥混凝土路面改为沥青混凝土路面前,对旧水泥混凝土路面进行综合处治进行了分析和论述。 相似文献
6.
Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002 相似文献
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Bambang Subyakto Toshimitsu Hata Isamu Ide Shuichi Kawai 《Journal of Wood Science》2001,47(3):199-207
Creep under fire of laminated veneer lumber (LVL) joined with metal connectors was studied. The fire-resistant performance of LVL butt joints connected with metal plates protected with graphite phenolic sphere (GPS) sheeting was discussed. The GPS sheeting was overlaid on the joint in different sizes and locations. The joint was exposed to a burner with a top flame temperature of 800°C and loaded with a load of 200 N to test for creep under fire. The results showed that the fire-resistant performance of the joint was markedly improved by the sheeting. The size and location of the GPS sheet significantly affected the time to rupture of the specimen, which was six times longer than that without GPS. Temperature measurements at the joint showed that the GPS sheeting distributed the heat along the surface and delayed failure. Thermographic images and analyses clarified the improvement in fire-resistant properties due to GPS. 相似文献
9.
Masashi Konoshima Charles W. McKetta Atsushi Yoshimoto 《Journal of Forest Research》2008,13(6):331-337
Forestry joint production choices require clear relative values for multiple, and often conflicting, management objectives.
Optimization is most difficult where values of forest attributes are: intangible, non-market, or sensitive. When most mathematical
programming models are adapted for non-commensurable objectives, there is little guarantee that vague relative preference
sets are met. We demonstrate how an iterative multiple objective programming approach finds preferred joint solutions in a
Native American tribal forestry case where marketable outputs are managed in the context of traditional culturally based forest
values. Without a priori specification of traditional tribal cultural values, conducting a series of feedback processes does
appear to identify more preferable solutions than other types of multiple-objective models that do not use feedback. 相似文献
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文章阐述了中澳合作青海林业资源管理项目实施过程中,引进和应用参与式方法和流域管理的理念,进行林业活动的设计和实施,全面总结了项目开展的主要林业活动,取得的成效和经验。项目的成功实施,为我们带来新的理念、新的管理方法和新的技术,取得的经验和做法值得我们在今后的生态环境保护和建设中借鉴。 相似文献