Behavior of Reinforced Concrete Beams Strengthened with Externally Bonded Hybrid Carbon Fiber–Glass Fiber Sheets

A comparative test program including six beams was carried out. Two strengthening systems, namely hybrid carbon fiber glass fiber-reinforced polymer (H-CF/GF-RP) strengthening and CF-reinforced polymer strengthening were used. The test results showed that the H-CF/GF-RP strengthening led to a significant increase of ductility with a slight influence on stiffness of strengthened beams.     

Nonlinear finite element analysis of reinforced concrete beams strengthened by fiber-reinforced plastics

Numerical analyses are performed using the ABAQUS finite element program to predict the ultimate loading capacity of rectangular reinforced concrete beams strengthened by fiber-reinforced plastics applied at the bottom or on both sides of these beams. Nonlinear material behavior, as it relates to steel reinforcing bars, plain concrete, and fiber-reinforced plastics is simulated using appropriate constitutive models. The influences of fiber orientation, beam length and reinforcement ratios on the ultimate strength of the beams are investigated. It has been shown that the use of fiber-reinforced plastics can significantly increase the stiffnesses as well as the ultimate strengths of reinforced concrete beams. In addition, with the same fiber-reinforced plastics layer numbers, the ultimate strengths of beams strengthened by fiber-reinforced plastics at the bottom of the beams are much higher than those strengthened by fiber-reinforced plastics on both sides of the beams.     

聚乙烯、聚丙烯废塑料回收利用进展

综述了近几年聚乙烯、聚丙烯废塑料回收再生利用技术进展,主要介绍了PE、PP废塑料分选技术、回收再生利用技术,包括物理法回收再生、化学法回收再生、发酵法以及热能再生。     

Development of an Efficient Connector System for Fiber Reinforced Polymer Bridge Decks to Steel Girders

This paper discusses the development of an innovative and efficient connector to be used with fiber reinforced polymer (FRP) decks supported by steel girders. A summary is provided detailing various proprietary connectors currently employed by FRP deck manufacturers. The paper then describes the development and experimental testing of a clamped shear stud-type connector. Experimental testing was conducted in two phases. The first phase consisted of individual connector testing. In this phase, several variations of the connector are tested and evaluated for strength, damage development, and overall performance. Results of this phase of testing are used to select a final connection design to be used in the second phase of testing, which consisted of testing a scale model bridge that incorporates several of the proposed connectors. The bridge is subjected to static load tests and the resulting reactions and deflections from these tests are compared with comprehensive finite element models of the system.     

Modeling of Tension-Stiffening Behavior of Reinforced Concrete Ties Strengthened with Fiber Reinforced Plastic Sheets

A model to analyze the behavior of reinforced concrete tension ties strengthened with fiber reinforced plastic (FRP) laminates is developed that allows introduction of a nonlinear constitutive relationship for materials and bond-slip laws at the steel and FRP interface. Experimental results are introduced and compared with analytical results confirming the model reliability. By using the model, a numerical study is carried out to provide evidence of the influence of the amount of fibers and the tension-stiffening behavior of strengthened elements. Considering elements with the same mechanical percentage of reinforcement but composed of different amounts of steel and fibers, the stiffness is influenced only after steel yielding, even if the crack width is reduced by the external strengthening. Finally, evidence is provided for the reduction of tension stiffening in strengthened elements due to reduction of crack spacing.     

真空成型在电冰箱行业中的应用

介绍了电冰箱塑料内胆生产中的2类真空成型方法即凸模成型和凹模成型，概括了真空成型产品设计、模具设计和加工中的注意事项。     

塑料工业与农业及三大支柱产业的关系

塑料工业与农业、汽车工业、建筑业及机械电子工业是相互发展、相辅相成的。本文分析并预测了至2000年我国农业及这三大支柱产业的前景及其对塑料工业的要求,说明了塑料与这些国民经济重要部门之间的密切关系。     

聚酰胺塑料在汽车工业的应用现状与前景

介绍国内外汽车用聚酰胺塑料的开发及应用现状与前景，对我国汽车聚酰胺塑料的研究和开发提出了相应的建议。     

云南可降解塑料的开发与应用刍议

介绍了可降解塑料技术开发的进展，分析了应用明景，评价了使用可降解塑料地膜的环境与经济效益，提出了云南开发与应用可降解塑料的对策与措施。     

87-SP淀粉塑料降解探索初报

就８７－ＳＰ淀粉塑料膜降解机理研究进行了初步探索，从田间覆膜和埋土试验中得出了该膜的降解速率和覆膜对土壤中蛋白酶活性、转化酶活性和接触酶活性的影响，并作了几十种有关的微生物在不同淀粉品种和不同组分情况试验，为淀粉塑料的工业生产和应用提供了大量必要的基础参数，并显示出值得探讨的有关降解相关的现象，初报表明，降解机理的探索对生产淀粉塑料是有很大意义的。