遗传算法在桥梁体外预应力加固设计中的应用

在桥梁加固设计中,体外预应力筋的设置受多种因素的影响.笔者运用基于实数编码的遗传算法,以水平筋的截面面积最小作为优化目标,提出体外预应力筋合理设置问题的优化方法.     

外、体内预应力混合配筋与节段预制拼装技术

体外、体内预应力混合配筋结构与节段预制拼装施工工艺相结合的解决方案具有广阔的发展前景，这种结构施工工艺简单、施工迅速、耐久性好，克服了一般后张预应力混凝土工艺复杂、耐久性差的缺点。结合凫洲大桥引桥工程（普通后张法施工的连续梁）进行对比分析。     

城市机动车出行交通总成本研究

通过分析机动车交通的社会成本构成要素,提出外部成本为交通的社会成本中不可忽视的部分,并界定各要素具体边界及范围,由此所构建的各组成部分的计算模型,可为政府部门制定相关的交通政策提供依据.     

一种前方车辆后轮接地点检测算法

现有车辆定位算法通常通过检测车辆底部阴影来定位车辆,该算法受阴影形状大小变化的影响较大,定位精度较低。该文提出了一种通过检测前方车辆后轮接地点来精确定位车辆的方法。首先通过垂直边缘和对称性测度实现路面车辆的初定位;然后利用车辆垂直边缘和后部水平边缘显著性的特点获得后车轮可能存在的感兴趣区(ROI);最后在该ROI中通过Tamura纹理特征的粗糙度对车轮和地面进行区分,精确地得到车轮接地点位置。     

Hepatic CT image query based on threshold-based classification scheme with gabor features

Hepatic computed tomography(CT) images with Gabor function were analyzed.Then a threshold-based classification scheme was proposed using Gabor features and proceeded with the retrieval of the hepatic CT images.In our experiments, a batch of hepatic CT images containing several types of CT findings was used and compared with the Zhao's image classification scheme, support vector machines(SVM) scheme and threshold-based scheme.     

Analysis Method of External Traffic Demand in City Area

To overcome the disadvantages of the existing method, a “dual four-stage” method” is put forward to analyze external traffic demand in city area considering the characteristics of external traffic. The method is carried out by two steps, and in the first step the city area is regarded as an overall traffic zone and the “four-stage” method of regional traffic demand analysis is used to obtain the total generation volumes of internal-external (IE) & external-internal (EI) trips of city area as well as the traffic volumes of both directions of all the arterial highways through the city in planning years. In the second step, the planning area of city is divided into several parts as internal traffic zones, and the external traffic zones are set near the junctions of highways and cordon line, then the “four-stage” method is applied for the second time to obtain the trip generation and distribution of IE & EI trips and (external-external) EE trips for internal traffic zones and external traffic zones in planning years. The application of the analysis on external traffic demand for comprehensive transportation planning of Zhenjiang City shows that the proposed method combines the advantages of influence area method and Cordon Line method it overcomes disadvantages of the two methods, and the results are more consistent with the real situation.     

具有值机功能的轨道交通机场线车站布局方案

近年来,随着国内机场客流量的高速增长及城市轨道交通建设步伐的加快,各大、中城市也开启了轨道交通机场线的建设。结合国内外机场提前值机的概念,以西安北客站至咸阳国际机场的轨道交通机场线为例,分析了值机客流的特征,研究了具备提前值机功能的轨道交通机场线车站布局的3个可行性方案,并指出了实现机场功能外移所存在的问题。     

绞吸式挖泥船外力计算软件及应用

介绍了绞吸式挖泥船外力计算软件的基本原理和功能,以2 000 m3/h绞吸式挖泥船为研究对象,把软件计算得到的结果与实际测量结果作比较,两者非常接近.设计者可以参考该软件计算得到的外力值合理选取相关的设计参数,同时也为结构计算提供了依据.     

桥梁体外预应力筋极限应力计算方法的评价与分析

根据现有的体外预应力混凝土试验梁数据,在理论分析的基础上对既有的多组体外预应力筋极限应力简化计算公式进行验证分析。通过对比分析可找出一组与试验结果吻合最好的极限应力计算公式。在此基础上再考虑现行桥梁结构设计的安全系数,可用以指导桥梁体外预应力结构的工程设计。