关于道路线形设计的几个问题的探讨

分析了道路线形设计的重要性,从路线总体设计和线形几何设计两方面对道路线形设计进行了深入探讨,强调了道路线形设计中应考虑的相关问题,以积累道路线形设计经验,完善道路线形设计。     

山区低等级公路复杂线形安全性检验研究

为研究山区低等级公路复杂线形的安全性,梳理了2种现有低等级公路线型检验的方法。为对实际山区道路的几何设计安全性、行驶速度一致性进行多维度分析,进一步开展了多元化研究,采用行驶动力学仿真的方法,通过Carsim软件构建车辆与道路耦合的仿真试验场景,对实际山区道路的几何设计安全性、行驶速度一致性进行了多维度分析。结果表明,山区道路的连续回头弯、弯坡组合的线形安全性较差,车辆会侵占对向车道,在连续小半径弯道位置处,速度较高时易发生侧翻。     

公路几何设计中协调性初探

公路几何设计中的协调性包括线形设计协调和外部景观环境的协调两个方面，从视觉原理出发，阐述了如何从线形设计的角度改善道路使用性能，提出了景观设置时需要注意的几个要点。     

公路线形的安全与美学设计

通过对构成公路线形的各几何要素的安全与美学效果的分析，论述了公路线形的安全与美观的设计方法和注意事项，为公路的线形设计提供了理论依据。     

关于公路安全设施设计中有关问题的探讨

道路安全影响因素有很多,涉及道路线形、路面状况、气候和天气、车辆种类和数量、安全设施布设等因素,本文主要从护栏、标志、标线等公路安全设施设计角度出发,对公路安全设施设计中存在的一些问题进行了讨论。     

公路线形设计因素对交通安全的影响分析

安全指标是开展公路工程设计首先要关注的关键性因素,当今的改进式线形结构设计对于增强行车的安全性最具有价值,完美的线形结构设计是确保实现行车安全的基本条件。公路工程的设计在启始阶段即需要关注线形结构的安全模式设计。论文从公路的线形结构特征、视距基准以及混合型线形组合形态和道路风景的紧密配合关系上阐释了公路线形结构设计形态对行驶安全的关联性,并指出了公路线形结构设计工作中需关注的若干问题,旨在使线式公路更能满足司机的视距及心态需求,以最大程度地实现交通顺畅。     

改扩建公路工程的线路设计要点研究

分析了改扩建公路设计原则与方法,重点对改扩建公路工程的线路设计要点进行了阐述,包含平面线形、纵面线形和线形组合,对改扩建公路线路的横断面加宽设计要点进行了归纳。通过这些设计要点的总结与分析,为改扩建公路设计提供参考,以促进改扩建公路工程的建设。     

道路线形设计对交通安全的影响

在进行道路线形设计时,设计的合理性对公路通车后的使用性能有着比较大的影响。因此,在进行设计时,需要充分考虑道路线形设计对交通安全造成的影响,并合理地进行设计,降低交通事故的发生概率。本文以实际情况为例,分析了道路线形设计对交通安全产生的影响,并对道路线形设计进行了探讨,达到了预期要求,可为类似工程提供借鉴。     

山区公路改建工程设计新思路

北京周边郊区大部分山区公路等级为3级或4级。由于建造年代较早,受当时经济条件、技术水平及交通量发展等情况制约,这些道路普遍存在平面线形差、曲线半径过小、视距不良、纵断面坡度大及横断布置较窄等问题。这些问题严重影响了公路行车的安全性和舒适性,通行能力也受到限制。以怀长路(九渡河—桥梓镇)改建工程为例,详细阐述了山区公路线形优化、局部路段经济技术比选、道路与周边环境的融合及沿线自然生态保护等设计细节问题,以期为今后类似的山区公路改建工程设计提供参考和借鉴。     

纬地道路辅助设计软件在公路设计中的应用

公路设计是公路工程项目的必要环节,设计质量直接影响工程的实施,公路的线形设计是至关重要的一步。公路线形设计是一项繁重而又十分细致的工作,一款简捷、实用的软件系统是必不可少的工具。本文较详细地介绍了应用纬地道路辅助设计系统软件在公路路线设计中的一些体会和认识。     

Buckling strength verification of cantilevered cylindrical shells subjected to transverse load using Eurocode 3

At present, there are only a few studies concerning the application of different types of buckling strength verification according to Eurocode 3 at combined loading. Besides the stress design as classical hand calculation method of checking cylindrical steel shells against buckling failure, the new Eurocode 3 also offers two global numerical analyses at different modelling levels. The linear buckling analysis (LBA) combined with a materially nonlinear but geometrically linear analysis (MNA) is the simpler concept from the perspective of the modelling and calculation effort. The more sophisticated method is a geometrically and materially nonlinear analysis of the imperfect structure (GMNIA). This paper presents the application of both numerical concepts to the cantilevered shell subject to a transverse load at the free edge. The results are compared to those from stress design. There are specific features at both types of numerical analysis: As the determination of the plastic reference resistance and the buckling parameters is the main focus at MNA/LBA, the choice of proper equivalent geometric imperfections demands special diligence at GMNIA. The presented analyses show that the GMNIA concept in connection with consistent equivalent geometric imperfections may lead to a safe and economic design of cylinders subject to combined loading. At the particular load case the MNA/LBA concept currently suffers from the lack of proper regulations concerning the determination of the overall buckling reduction factor.     

弹性与弹塑性动力时程分析方法中若干问题探讨

依据大量实际工程弹性、弹塑性动力时程分析经验,结合实际工程应用,探讨了弹性、弹塑性动力时程分析方法中的一些基本问题。针对性地分析了动力时程分析方法中地震波的离散性;地震波如何与反应谱曲线在统计意义上相符;人工模拟地震波方法及其工程应用;弹性、弹塑性时程分析法选取地震波的基本原则;弹性时程分析法地震波的选取数量;如何将反应谱分析结果与时程分析结果取较大值等方面的问题。通过大量的算例分析可以看出,正确地应用弹性、弹塑性动力时程分析方法需要从多个方面进行准确理解和把握,教条地应用很难发挥弹性、弹塑性动力时程分析应有的作用。     

常州市体育馆椭圆抛物面弦支穹顶稳定性研究

常州市体育馆椭圆抛物面钢屋盖采用由Levy索杆系和单层网壳构成的弦支穹顶结构,与已研究的常规弦支穹顶相比,其具有体量大,矢跨比高和外形为椭圆抛物面的特点。将弦支穹顶与单层网壳进行稳定性对比研究,包括构件屈曲、线性屈曲和几何非线性屈曲等,分析了高矢跨比弦支穹顶中索杆系的作用以及对结构设计起控制作用的破坏形式。研究结果表明,索杆系增加了弦支穹顶的整体性,降低了其对初始几何缺陷的敏感性,但对结构刚度、基本自振周期和模态、构件屈曲荷载、线性屈曲荷载、无初始缺陷的非线性屈曲荷载、屈曲模态等影响不大。高矢跨比弦支穹顶仍对初始缺陷较为敏感,稳定性仍是结构设计控制因素之一。此外,由于椭圆抛物面外形,活荷载布置形式对结构屈曲模态影响较大,且满跨活荷载并不一定是最不利的活荷载布置形式。     

A graph- and feature-based building space recognition algorithm for performance simulation in the early design stage

This paper presents a graph- and feature-based building space recognition algorithm for a boundary representation format (B-rep) geometric model, which can identify the building element type and space. The flow of the algorithm is described in detail, including the construction of a building geometric topology relation graph (BTG), the recognition of building element type, and the extraction of building space based on graph and local feature. The algorithm can be applied to the design of a building scheme; it can quickly identify and transform the geometric model into the input model required by the performance simulation software. This is a key step in realizing a performance-oriented design in the early design stage. We implemented this algorithm using SketchUp for testing its performance. Through the case study, it is proved that the algorithm can recognize the model and extract all the building spaces accurately. There is linear correlation between the recognition time and number of faces. Moreover, at the time of analysis, a model composed of 500 spaces and 3001 faces did not exceed 1.69 s, which meets the requirements of most applications well. Compared to previous works, this algorithm performs well in both recognition accuracy and time efficiency simultaneously, and can better serve the actual demand of automatic real-time building performance feedback in the early design stage. Finally, the future work regarding performance-oriented design based on model recognition is proposed.     

Kiewitt型单层球面网壳结构风振响应分析

采用随机模拟时程分析方法,对Kiewitt6-6型单层球面网壳结构的风振性能进行了系统的参数分析,考察了几何、气动、结构等参数变化对结构风振响应规律的影响。通过对计算结果的进一步统计处理,给出了可供该类结构抗风设计参考的风振系数拟合公式。研究结果表明,该类结构的风振响应规律性较好,风振系数取值为3.0左右。     

曲线桥梁几何设计

公路桥梁设计中位于曲线上的桥梁几何设计比较繁琐，既要照顾到纵横线形符合规范要求，又要与布孔及桥梁结构设计相适应，还要考虑到施工的可操作性。主要介绍了含有直线、缓和曲线、圆曲线的曲线桥梁几何设计，并结合工程实例提出了装配式梁桥在设计和施工中处理桥面超高，加宽的一些实用办法。     

A parametric investigation of the acoustical performance of contemporary mosques

Acoustics is an important factor in mosque prayer halls that had not been given extensive concern during the architectural design stages. Eventually, the importance of speech intellig- ibility became more important, given the integration of other activities into the prayer halls, such as the holy Quran recitation, speeches, and lectures. Early attempts have been made to control the propagation of sound and to maintain good acoustic quality within the prayer spaces. Architects during the conceptual design stage had barely paid attention to the design issues that affect the acoustic environment inside the prayer zones, which is either due to lack of time during the project development or, in most cases, a lack of simple design guidelines to overcome any drastic acoustical defects arising from the incorrect design, shape, or material selection. The basic guidelines for designers to select the appropriate shape, geometry, size, and finishing materials are an essential design tool. This work examines the three common design topologies of mosques, which differ in size, shape, and finishing materials. In this study, a geometric and material parametric analysis was conducted based on the shape, surface area, volume, and finishing materials of each of the three designs. For the geometric acoustics, a computer model employing the ray tracing theory was employed to investigate the three configurations. Different acoustic treatments were tested relative to the geometric disposition of each design. Finally, basic recommendations and design guidelines were presented.     

钢管桁架屋盖结构的极限承载力分析

对某体育馆的钢管桁架屋盖结构进行极限承载力分析,取用两种不同的模型,同时考虑几何非线性及材料非线性,采用逐步加载的方法,得到了荷载一位移全过程曲线。分析结果表明,该屋盖结构具有一定的安全储备,对结构的局部进行优化设计,既能满足承载力要求,又能取得较好的经济效益。     

Geometric proportions: The underlying structure of design process for Islamic geometric patterns

This paper discusses geometric proportions which serve as a design tool, especially for Islamic pattern design. The key role of geometry in Islamic patterns is discussed with relation to proportions which act as the underlying structure of the design process. Evaluations based on spatial structure and esthetic criteria are integrated into the conceptual phase of the design process. Proportions serve two objectives; firstly, in pattern design, proportions are strongly linked to geometry, which can be viewed as a self-guiding method of esthetically proven design. Secondly, geometric proportions regulate primarily the order of patterns; while at the same time they mediate between the two poles of order and diversity as well as among different esthetic levels. This paper analyzes geometric principles and design features of traditional Islamic patterns, involving geometric proportion analysis. It also describes the syntheses of Islamic patterns from the perspectives of Islamic cosmology, philosophy and metaphysics of geometry, which can be seen as following a pre-established principle of geometric and proportional design with high accuracy and great precision. Furthermore, the underlying relationship between cosmology and geometry is manifested in Islamic patterns where geometry acts as the vocabulary underpinning the pattern language. These findings support the argument that geometry was independently discovered and applied by Islamic culture as a universal language, constituting one of the most important multicultural symbols in design.     

非线性体：表现复杂性

文章试图从20世纪建筑理论系统演化的规律,说明非线性建筑探索代表了世界建筑发展的方向。这一新的建筑探索是复杂科学理论在建筑设计上的反映,并依靠计算机技术手段解决综合性复杂问题,建筑设计的结果表现为非线性形体,即具有动态趋向的流动性不规则体量。文章同时强调这一设计方法的起点应回到地段并从现象出发,以避免陷入新的形式主义的误区;并指出图解是这一设计方法的核心逻辑。