索承式桥梁吊索钢丝腐蚀疲劳寿命评估

根据吊索镀锌钢丝腐蚀疲劳破坏特点,把镀锌钢丝腐蚀疲劳纹形成和扩展过程分解成镀锌层腐蚀失效、蚀坑萌生、蚀坑形成、短裂纹扩展、长裂纹扩展和断裂破坏等阶段,建立各阶段时间表达式,得到镀锌钢丝疲劳寿命表达式,提出基于断裂力学的吊索钢丝腐蚀疲劳寿命评估研究结果方法。通过算例分析复杂运营条件下腐蚀环境和应力幅等因素对吊索钢丝腐蚀疲劳寿命的影响,研究结果表明：吊索钢丝腐蚀疲劳寿命主要由钢丝镀锌层腐蚀、蚀坑发展和短裂纹扩展等3个阶段组成,为了准确地评估吊索腐蚀疲劳寿命,需要掌握大桥的运营环境和交通荷载。     

考虑时变因素修正的混凝土斜拉桥换索前初态模型

为准确掌握混凝土斜拉桥换索施工前的索力和主梁受力状态,建立的换索施工前的初态分析模型,需要对其运营期间混凝土收缩徐变、预应力索应力松弛、恒载性超载等因素产生的影响进行评估。而混凝土弹性模量、徐变、收缩及预应力筋松弛等因素具有与时间历程和应力历史紧密关联的材料非线性特征,采用有限元增量分析是合理的选择。为此,在时间历程划分的基础上,推导了考虑材料徐变、松弛、收缩影响的弹塑性有限元求解方程,建立了时间增量步内单元计入徐变、收缩、松弛影响的数值函数表达式,给出了斜拉索损伤刚度修正的具体措施和恒载性超载影响计入的分析方法,建立的初态模型分析技术进一步改善了混凝土斜拉桥运营期的桥梁状态评估方法。     

模式识别的斜拉桥损伤诊断动力指纹与识别算法

为有效并准确诊断出斜拉桥损伤,对基于模式识别的斜拉桥损伤诊断方法进行了研究。选取易于测试出的低阶模态频率和部分关键点竖向振型数据为动力指纹,无需模态扩展或模型缩聚。研究并采用全因子设计进行动力指纹库的创建,可精确评估设定的损伤因子及其交互作用对损伤识别结果的影响。设计并增加了带随机误差的动力指纹库样本集。编制了基于Matlab的模式识别的多种算法,重点研究了精确度高的多层感知器识别算法及其提高该算法预测准确率的装袋集成算法。最后给出一座单塔双跨双索面斜拉桥的多种识别算法的损伤诊断过程和结果,得到一种可包容测试随机误差的高精确度斜拉桥损伤诊断评估模型。     

Fault check & safeguard system of optical cable for communication based on GIS

Once fault occurs on the optical cable, it will seriously impair communication. In order to solve the terrible result caused by faults, the system implements the management of the spatial database of the optical cable and the information along it and location fault spots with celerity and legitimacy, according to the spatial and environmental characteristics on geographic distribution of the optical cable network and based on GIS, as it displays the multimedia information around the fault spot, such as landform and physiognomy. Combining the buffer with path analysis function of GIS, the system searches for the optimum path to the fault spot on the optical cable, and also gives emergency schemes to dispose the fault. This application has gained a satisfactory result for effectively managing communication optical cable resources, shortening the repair time, and diminishing the loss caused by faults.     

高烈度区斜拉桥横向约束方案优化分析

为了确定强震作用下斜拉桥合理的横向抗震约束体系,以可克达拉大桥为工程背景,采用非线性时程分析法,分析了4种横向约束体系即横向滑动体系、全限位体系、位移相关型减震体系和速度相关型减震体系对强震区大跨度桥梁地震响应的影响,重点对钢阻尼器的屈服荷载和黏滞阻尼器的位置及相关参数进行优化分析,并与其他体系的地震响应进行了对比。结果表明：在强震作用下,对于大跨度桥梁横向滑动体系和全限位体系均不是理想的抗震体系;而在墩梁、塔梁之间设置减隔震装置可以有效减少横桥向的墩梁、塔梁的相对位移及地震剪力和弯矩;然而,从桥梁正常使用的角度来看,塔梁之间布设横向钢阻尼器装置优于黏滞阻尼器装置。     

A forward algorithm for prestressed construction process of large-span suspendome based on the equivalent pre-tension

To accurately simulate prestressed construction process of large-span suspendome, the initial state of construction process according to practical construction sequence is established, and the construction mechanical analysis for prestressed construction process is especially studied. Features of prestressed construction process of large-span suspendome are summarized, and the insufficiencies of the application of state variable superposition method, back analysis method, birth and death element method are analyzed. Combined with nonlinear finite element analysis method, forward algorithm for prestressed construction process based on the equivalent pre-tension is proposed, and the specific application method and procedure are given. Changzhou stadium steel roof engineering is taken as an example to verify the practicability and applicability of forward algorithm for prestressed construction process. The conclusion is that, using forward algorithm for prestressed construction process based on the equivalent pre-tension, the structure state of each construction phase can be accurately tracked, and the nonlinear contact of strut and rigid framework, interactive impact of cable force, conversion of temporary structure system, and structural geometric nonlinearity can be comprehensively considered.     

Setting of fire scenarios in performance based characteristic coefficient on the optimal quantity of concrete walls

China has no fire protection regualtion about the ancient buildings, and the research on this issue is limited in China.This paper proposes some very important issues in the setting of fire scenarios for ancient buildings, especially the spread of fire. It discusses the criterion and process of fire scenario setting. The integrity procedure of fire scenario setting includes the fire position set, the fire development curve set and the fire spread analysis. Two ways of the fire spread are proposed.     

不同成膜剂对玉米噻虫啉悬浮种衣剂的持效性及安全性影响

为明确含不同成膜剂的噻虫啉种衣剂处理玉米种子后在土壤和植株中的持效性及其对刺吸式害虫的防治效果,选择3种不同成膜剂加工成的噻虫啉悬浮种衣剂以400 g a.i. 100 kg–1种子浓度包衣处理,分别于室内和田间条件下测定其对玉米出苗率、生长量和生理生化等方面的影响,及噻虫啉在玉米叶片和土壤中的持效期,并评价其对刺吸式害虫的防治效果。结果表明,ZY904-3和ZY904-5成膜剂的噻虫啉种衣剂处理对玉米出苗没有影响,3种成膜剂的噻虫啉拌种对玉米生长量和生理生化活性均有不同程度促进,玉米叶片和土壤中的噻虫啉持效期较未加成膜剂有一定延长,ZY904-1、ZY904-3和ZY904-5处理的噻虫啉悬浮种衣剂(FS)在叶片和土壤中持效期分别延长了20～40d、20～30 d和10～20 d。3种成膜剂处理可有效防治玉米刺吸式害虫, ZY904-1和ZY904-3成膜剂的噻虫啉种衣剂处理对玉米刺吸式害虫数量有很好的控制作用,分别于播种80 d (室内)和60 d (田间)后防效仍达50%以上,但ZY904-1成膜剂的噻虫啉种衣剂推迟出苗时间。综合各个方面, ZY904-3成膜剂的噻虫啉种衣剂拌种...     

植物油替代二甲苯配制的甲维盐EC对“上海青”的安全性影响

作者在观察以精制松树油+棕榈油、精制松树油、棕榈油等三种植物油替代二甲苯为溶剂的1%甲氨基阿维菌素苯甲酸盐EC对“上海青”（Brassica campestris L.）的药害情况的基础上,测定了“上海青”体内蛋白质、氨基酯和叶绿素等营养物质的含量以及对植株株高的影响,以探讨植物油替代二甲苯配制的甲维盐EC对”上海青”的安全性。结果表明,精制松树油+棕榈油、精制松树油两种溶剂配制的甲维盐EC对“上海青”无明显药害;二甲苯、棕榈油两种溶剂配制的甲维盐EC高浓度处理会引发“上海青”药害。二甲苯溶剂配制的甲维盐EC造成“上海青”新叶畸形且不可恢复;棕榈油溶剂配制的甲维盐EC造成“上海青”叶片叶缘枯白、植株萎蔫,但在植株的后续生长中症状消失。植物油溶剂配制的甲维盐EC施用后,高浓度处理会引起“上海青”体内蛋白质含量的明显下降,三种浓度处理均会引起“上海青”体内的氨基酸含量上升,但对“上海青”的叶绿素含量无明显影响。植物油溶剂配制的甲维盐EC施用后对“上海青”的生长无明显影响。