H(2)-Unknotting Operation Related to 2-Bridge Links

This paper concerns the H(2)-unknotting numbers of links related to 2-bridge links. It consists of three parts. In the first part, we consider a necessary and sufficient condition for a 2-bridge link to have H(2)-unknotting number one. The second part concerns an explicit form of composite links with H(2)-unknotting number one. In the last part, we develop a method of studying the H(2)-unknotting numbers of some tangle unknotting number one knots via 2-bridge knots.Comment: 14 pages, 9 figure

Design of RC-active oscillators using composite amplifiers

The design of composite opamp Wien-Bridge oscillators is systematically approached by using a general model including amplitude control issues. Two different design criteria are presented and their main features summarized. A general composite opamp topology from which a catalog of structures can be obtained in a systematic way is presented. Experimental data are included illustrating the performance of the proposed design criteria

Parametric Studies on Composite Bridges: Bending Moment Analysis

The research is about parametric studies on composite bridge and integral composite bridge that are designed by using Eurocodes. Besides, the research will also show the comparison between BS and Eurocodes by using composite bridge as example. In Malaysia today, most engineering firms are still using British Standards as their code of practice whereas worldwide firm may have shifted to Eurocodes. On the other hand, bridges in Malaysia are mostly purely composite types which needed much maintenance cost if compared to integral composite bridge. The research will show all the methods used to design both types of bridges with two different codes. Specific graphs, diagrams and flow charts are used to help readers get better understanding when reading through. Design calculation is done by using manual calculation, working example and also spreadsheet. For software modeling, CSI Bridge 2014 and Oasys GSA have been used. These software helps on designing of composite bridges on Eurocodes which were used for comparison. Results of the research show the live loading of Eurocodes bridge design is lesser than the British Standard bridge design. Results also show that with different parameters used on the bridge, different value of stresses will acting on the bridge structures. Future recommendations have also been show in the later part of this report

Lateral distribution calculation of multi-I beam composite curved bridge with slip effect

This paper presents a modified rigid cross beam method to study the lateral distribution of multi-I beam composite curved bridge with slip effect. First, the effective stiffness expression of single composite curved beam with slip effect were established and calculated by the FEM. Secondly, the lateral load distribution of multi-I beam composite curved bridge is obtained by substituting the effective stiffness of the main composite curved beam into the rigid cross beam method. Finally, The FEM numerical examples show that this method can accurately describe the load distribution characteristics of multi-I beam composite curved bridge with slip effect

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

INE/AUTC 12.0

Design and Testing of a Concrete Safety Barrier for Use on a Temporary FRP Composite Bridge Deck

Fiber-reinforced polymer (FRP) composite materials can be used for the fabrication of lightweight, corrosion-resistant honeycomb sandwich panels, representing a convenient and economical alternative to traditional steel RC for bridge decks. Composite panels are particularly advantageous for the construction of temporary bridge structures in terms of both ease of construction and reusability of panels. Although FRP sandwich panels have been considered for the construction of bridge decks, no barrier system has been developed and crash tested for use with this specific type of deck. The objective of this research project was to develop a crashworthy concrete barrier system for use with temporary FRP composite bridge decks. Upon failure of a full-scale crash test with a New Jersey concrete safety shape barrier, an accurate analysis of the potential problems led to a series of design modifications to the barrier as well as to the attachment between the composite deck and both the bridge structure and the barrier. The second design, which used a vertical-faced barrier, was successfully crash tested according to Test-Level 3 impact safety standards set forth in the AASHTO Manual for Assessing Safety Hardware (MASH)

Evaluation of safety performance during construction and servicing stages of Liuxi river bridge

Prestressed concrete continuous beam-arch composite bridge with concrete-filled steel tube is a new type of bridge developed in recent years. It has the characteristics of strong spanning ability and large in-plane stiffness, but the lateral stiffness of the arch ribs for this type of bridge is relatively weak. In order to effectively improve the construction quality and structure stability, and optimize the mechanical properties, and in addition of realize the design of large span continuous beam-arch composite bridge, a comprehensive safety assessment of the Liuxi River bridge during construction and serving stages located in China was conducted in this paper. The results show that the bridge had favorable safety margin during the construction and severing stages. The outcomes of this study can provide technical support for the safety and smooth implementation of the bridge’s safeguard, which has important theoretical significance and engineering application value