Multi‐objective highway alignment optimization using a genetic algorithm

The available highway alignment optimization algorithms use the total cost as the objective function. This is a single objective optimization process. In this process, travel‐time, vehicle operation accident earthwork land acquisition and pavement construction costs are the basic components of the total cost. This single objective highway alignment optimization process has limited capability in handling the cost components separately. Moreover, this process cannot yield a set of alternative solutions from a single run. This paper presents a multi‐objective approach to overcome these shortcomings. Some of the cost components of highway alignments are conflicting in nature. Minimizing some of them will yield a straighter alignment; whereas, minimizing others would make the alignment circuitous. Therefore, the goal of the multiobjective optimization approach is to handle the trade‐off amongst the highway alignment design objectives and present a set of near optimal solutions. The highway alignment objectives, i.e., cost functions, are not continuous in nature. Hence, a special genetic algorithm based multi‐objective optimization algorithm is suggested The proposed methodology is demonstrated via a case study at the end.     

浅谈筑路机械设备管理

文章通过分析筑路机械设备管理的背景和意义,针对目前筑路机械设备管理存在的问题,提出了相关对策,为公路施工企业提高筑路机械设备管理水平提供借鉴。     

姚东大桥悬浇前支点挂篮施工技术

前支点挂篮施工工艺复杂,技术含量高。文章结合余姚姚东大桥施工实践,分析了前支点挂蓝的设计原理和技术难点,介绍了前支点挂篮在混凝土斜拉桥主梁悬浇施工中的工艺及注意事项。     

罗天乐大桥连续刚构0#块施工托架设计方法

文章介绍了罗天乐大桥连续刚构0#块施工托架的设计与计算方法,指出所采用的预埋牛角焊接型钢托架法具有取材方便、组装速度快、变形小、安全性高、经济适用等优点,适合高墩施工和无基础支撑条件的墩桩施工,可供同类型桥梁工程施工参考。     

Augmented Reality Vehicle system: Left-turn maneuver study

Augmented Reality “AR” is a promising paradigm that can offer users with real-time, high-quality visualization of a wide variety of information. In AR, virtual objects are added to the real-world view in real time. The AR technology can offer a very realistic environment for enhancing drivers’ performance on the road and testing drivers’ ability to react to different road design and traffic operations scenarios. This can be achieved by adding virtual objects (people, vehicles, hazards, and other objects) to the normal view while driving an actual vehicle in a real environment. This paper explores a new Augmented Reality Vehicle “ARV” system and attempts to apply this new concept to a selected traffic engineering application namely the left-turn maneuver at two-way stop-controlled “TWSC” intersection. This TWSC intersection experiment, in addition to testing the feasibility of the application, tries to quantify the size of gaps accepted by different driver’s characteristics (age and gender). The ARV system can be installed in any vehicle where the driver can see the surrounding environment through a Head Mounted Display “HMD” and virtual objects are generated through a computer and added to the scene. These different environments are generated using a well defined set of scenarios. The results from this study supported the feasibility and validity of the proposed ARV system and they showed promise for this system to be used in the field-testing for the safety and operation aspects of transportation research. Results of the left-turn maneuver study revealed that participants accepted gaps in the range of 4.0-9.0 s. This finding implies that all gaps below 4 s are rejected and all gaps above 9 s are likely to be accepted. The mean value of the left-turn time was 4.67 s which is a little bit higher than reported values in the literature (4.0-4.3 s). Older drivers were found to select larger gaps to make left turns than younger drivers. The conservative driving attitude of older drivers indicates the potential presence of reduced driving ability of elderly. Drivers’ characteristics (age and gender) did not significantly affect the left-turn time. Based on the survey questions that were handed to participants, most participants indicated good level of comfort with none or small level of risk while driving the vehicle with the ARV system. None of the participants felt any kind of motion sickness and the participants’ answers indicated a good visibility and realism of the scene with overall good system fidelity.     

A model for the visualization and analysis of elevator traffic

ABSTRACT

Analysis of elevator traffic in high rise buildings is critical to the performance evaluation of elevator group control systems (EGCS). Elevator dispatching methods or parking algorithms in an EGCS can be designed or modified according to analyses of traffic flow. However, interpretation of traffic flow based solely on numerical data may not be explicit and transparent for EGCS experts as well as for other non-expert building administration. In this study, we present a model for visualization and analysis of elevator traffic. First, we present an alternative approach for traffic analysis which we call route visualization. In the proposed approach, we initially decompose elevator traffic into its component parts and investigate each component independently. Then, using superposition of components we obtain a reconstructed model of overall traffic. This modeling approach provides component-based traffic analysis and representation of routes with intensities through data visualization. In the second part we introduce a multi-dimensional analysis of time parameters in ECGS. This approach provides a comparative analysis of several control algorithms such as dispatch or park algorithms for different combinations of traffic components.     

静态爆破法在深圳地铁施工中的应用

静态爆破是近年来发展起来的一种新型爆破施工技术,它可在无震动、无飞石,无噪音、无污染的条件下破碎或切割岩石或混凝土构筑物。深圳地铁2号线东延线土建工程安托山站—侨香站区间矿山法施工竖井系选用此工法在2 500 mm×3 000 mm雨水箱涵附近成功地进行了中、微风化花岗岩开挖施工,确保了雨水箱涵的安全性。     

缆索吊装系统在钢桁架拱桥上构施工中的应用

文章以新世纪大桥主桥钢桁架上构施工为例,对施工所需缆索吊装系统的承重主索、塔架、地锚、扣挂体系进行了介绍,并阐述了利用缆索吊装系统进行钢桁架拱桥上构施工的工艺流程及技术要点。     

高速公路“三背”回填施工及质量控制探讨

文章介绍了高速公路桥台背、涵背、挡土墙墙背（简称＂三背＂）的回填施工工艺,阐述了＂三背＂回填的施工、检测要求及质量控制措施。     

施工最大悬臂状态梁桥P-Δ效应有限元分析

文章以赣江大桥和宁海新桥特大桥为研究对象,利用有限元模型对其主桥施工最大悬臂状态下P-Δ效应进行了计算,分析了考虑P-Δ效应时的桥梁位移与应力变化情况,为今后类似工程的设计计算和施工监控提供参考。