公路边坡培植柠条的探讨

介绍了河曲公路所处的自然环境 ,阐述了人工铲草的利与弊 ,进而提出了边坡培植柠条的效益分析 ,并对培植柠条的苗期管理及与养护生产的关系进行了介绍     

主跨348m+348m三塔单索面PC梁斜拉桥

宜昌市夷陵长江大桥采用三塔斜拉桥，总体布置为(128．08 348 348 120．35)m。介绍了该桥的合理性及结构特点。     

Neural networks for contract bridge bidding

The objective of this study is to explore the possibility of capturing the reasoning process used in bidding a hand in a bridge game by an artificial neural network. We show that a multilayer feedforward neural network can be trained to learn to make an opening bid with a new hand. The game of bridge, like many other games used in artificial intelligence, can easily be represented in a machine. But, unlike most games used in artificial intelligence, bridge uses subtle reasoning over and above the agreed conventional system, to make a bid from the pattern of a given hand. Although it is difficult for a player to spell out the precise reasoning process he uses, we find that a neural network can indeed capture it. We demonstrate the results for the case of one-level opening bids, and discuss the need for a hierarchical architecture to deal with bids at all levels.     

柔性纤维混凝土的疲劳特性研究

将柔性纤维掺入水泥混凝土可以大幅度提高混凝土的弯曲疲劳等路用性能,并通过试验建立了柔性纤维混凝土的疲劳方程.结果表明,柔性纤维不但能使混凝土的强度提高,更主要的是可以在重交通条件下,可成倍地提高混凝土的弯曲疲劳寿命.     

铝电解多功能天车轨道接头磨损的机理分析

分析铝电解多功能天车轨道接头的受力情况、轮轨磨损机理和现场采集的数据照片,指出轨道经过碾压后的硬度变化以及氧化铝灰对天车轨道接头磨损的影响,提出相应措施.     

桥梁颤振气动导数识别的迭代法

本文提出一种利用自由振动响应通过年顿－拉夫逊迭代同时识别出桥梁全部8个颤振气动导的方法。此法具有对迭代初值要求不高，识别结果稳定的特点，并具有一定的抗噪声干扰能力。数字仿真与实物试验结果表明本文方法有效，可行。     

An investigation of the relation between the temperature dependences of the initial unbalance and the output signal of resistance strain sensor bridge circuits

The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage under external physical action. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007.     

阳泉市煤矿采空区地质因素对公路的破坏

介绍了阳泉市煤矿采空区对公路建设所造成的危害，对其上覆岩层变形破坏的地质因素及其破坏机理作了分析，指出应该采取各种措施减少对公路的破坏。     

Assessment of Highway Bridge Upgrading by Dynamic Testing and Finite-Element Model Updating

The Land Transport Authority of Singapore has a continuing program of highway bridge upgrading for refurbishing and strengthening bridges to allow for increasing vehicle traffic and increasing axle loads. One subject of this program has been a short-span bridge taking a busy main road across a coastal inlet near a major port facility. Experiment-based structural assessments of the bridge were conducted before and after upgrading works including strengthening. Each assessment exercise comprised three separate components: (1) a strain and acceleration monitoring exercise lasting approximately one month; (2) a full-scale dynamic test carried out in a single day without closing the bridge; and (3) a finite-element model updating exercise to identify structural parameters and mechanisms. This paper presents the dynamic testing and the modal analysis used to identify the vibration properties and the quantification of the effectiveness of the upgrading through the subsequent model updating. Before and after upgrade, similar sets of vibration modes were identified, resembling those of an orthotropic plate with relatively weak transverse bending stiffness. Conversion of bearings from nominal simple supports to nominal full fixity was shown via model updating to be the principal cause of natural frequency increases of up to 50%. The utility of the combined experimental and analytical process in direct identification of structural properties has been proven, and the procedure can be applied to other structures and their capacity assessments.     

斜拉桥动力特性的参数分析

建立了斜拉桥动力分析的三维有限单元模型 ,研究了单元类型和参数变化对斜拉桥动力特性的影响。详细地讨论了斜拉桥非线性来源 ,并运用 6节点薄壁单元和 4节点索单元分别考虑了斜拉桥弯曲构件和索的非线性特性。通过对一斜拉桥的数值分析 ,得到了关于斜拉桥动力参数敏感性的一般结论。