峡谷河流的挂网式人行悬索桥设计

为了降低峡谷河流人行悬索桥的造价,本文提出一种峡谷河流的双曲抛物面空间缆索挂网式人行悬索桥,将双曲抛物面空间缆索网分散锚固于峡谷河流两侧的悬崖陡壁岩石之上,取消桥塔,取消吊索体系,管桁架式桥面加劲梁直接搁置在双曲抛物面空间缆索网之上,节约造价,装配式施工简便。结合某150m跨径峡谷河流人行景观悬索桥,建立Midas有限元分析模型,开展动力模态特性分析研究,验证了双曲抛物面空间缆索挂网式人行悬索桥结构具有良好的抗风稳定性。     

An investigation into the isolation performance of mono-and bi-stable systems

Motivated by the need for improving the isolation performance, many research studies have been performed on isolators with nonlinear characteristics. Based on the shape of their phase portrait, such devices can be configured as either a mono-or bi-stable isolator. This paper focuses on investigating the relative performance of these two classes under the same excitations. Force transmissibility is used to measure the isolation performance, which is defined in terms of the RMS of the ratio of the transmitted force to the excitation force. When the system is subjected to harmonic excitation, it is found that the maximum reduction of the force transmissibility in the isolation range using Quasi-Zero stiffness is achieved. When the system is subjected to random excitation, it has the same effect of Quasi-Zero stiffness. Further, optimum damping can be changed with stiffness and has minimum value.     

Assessing the impact of the built environment on travel behavior: a case study of Buffalo,New York

Assessing the impact of characteristics of the built environment on travel behavior can yield valuable tools for land use and transportation planning. Of particular interest are planning models that can estimate the effects of ‘smart growth’ planning. In this paper, a post-processor method of quantifying and searching for relationships among many aspects of travel behavior and the built environment is developed and applied to the Buffalo, NY area. A wide scope of travel behavior is examined, and over 50 variables, many of which are based on high-detail data sources, are examined for potentially quantifying the built environment. Linear modeling is then used to relate travel behavior and the built environment, and the resulting models may be applied in a post-processor fashion to travel models to provide some measure of sensitivity to built environment modifications. The study’s findings demonstrate that mode choice is highly correlated to measures of the built environment, and that many of the principles of smart growth appear to be a valid way to encourage non-vehicle travel. Home-based VHT and VMT appear to be affected by the built environment to a lesser degree.