A frequency-domain regression method for estimating building foundation heat transfer

In this article, the Interzone Temperature Profile Estimation solutions are first utilized to carry out a frequency analysis for the foundation heat transfer to determine the effect of indoor air and ambient air temperature fluctuations on the variation of the foundation heat loss/gain. Then, a frequency-domain regression-based method is used to develop transfer functions for ground-coupled surfaces. The regression frequency-domain method is tested and validated using one-dimensional heat transfer for above-grade walls. It is found that the proposed method provides a more effective alternative than numerical methods to estimate conduction transfer function coefficients for building foundations and thus can be easily implemented in whole-building simulation programs.     

基于主动控制的高层结构最优抗侧刚度

传统的结构抗震设计方法需要设计者凭经验来试算抗侧刚度,被动且耗时、费力.本文基于振型分解反应谱理论,提出了主动控制结构抗侧刚度的计算方法,严格推导出求解控制刚度的迭代公式,并证明高层建筑结构各层层间位移达到最大层位移限值时其刚度分布即为最优.针对实际情况,提出了高层结构优化设计的建议.     

高层建筑结构侧向刚度规则性计算方法研究

GB50011-2001《建筑抗震设计规范》提出的"层间剪力位移比"的计算方法对侧向刚度规则性的判断存在局限性,在一些特殊情况下会得出不正确的结论,为了解决侧向刚度规则性判断的问题,提出了"层间剪力位移角比"的侧向刚度计算方法,结合算例可以看出,对于以弯曲变形为主的结构,此方法结构概念明确,得出的结论符合工程经验,是对规范方法的很好的补充。     

桩的抗压刚度结构

为得到计算受压桩的沉降、承载力并能分析压力在桩中传递规律的方法,对受压桩的物理现象进行研究。运用系统论中的结构方法,将桩和土作为桩-土受压系统,并建立该系统的抗压刚度结构,来揭示桩与桩侧土和桩底持力层三元素抗压功能之间的内在联系,揭示桩的抗压功能的构成方式,创造性地获得桩-土系统的集成抗压刚度数学模型,并且提出了受压桩简明、实用的计算方法。用试验数据进行计算,结果与实测相符。研究表明,建立的桩的抗压刚度结构,具有普遍性,符合客观规律,它的抗压功能,反映了抗压桩的功能;集成抗压刚度在概念上和理论方面,比目前采用的方法要完善得多。桩的抗压刚度结构的建立,是研究抗压桩机理的有效途径,它为桩基的设计计算,提供了新思路,搭设了新的研究平台。     

带边框RC低矮抗震墙实用计算方法

带边框低矮抗震墙在建筑结构设计中应用广泛,其受力性能复杂,在地震作用下一般发生剪切破坏.以试验研究及有限元分析结果为基础,分析了带边框低矮抗震墙的承载机理.利用等效斜压杆的方法,给出了无洞及开洞带周边框架RC低矮抗震墙的受剪承载力和不同受力阶段刚度的计算公式,并与试验结果进行了比较.研究结果可供设计计算时参考.     

多种结构抗侧刚度计算方法对比

对常见的剪切刚度、楼层剪力与层间位移比、剪弯刚度三种结构抗侧刚度计算方法展开分析,探究各方法的适用性及优缺点,结果表明,剪切刚度为剪弯刚度简化计算方法,其可应用于结构方案阶段,当1≤h/b≤4时,计算误差较大;按楼层剪力与层间位移的比值计算侧向刚度时,由于存在无害位移影响,其计算结果往往偏小;采用剪弯刚度可以较为精确合理计算结构抗侧刚度,其计算代价也较高。     

Optimal design method for building energy systems using genetic algorithms

In this paper, a new optimal design method for building energy systems is proposed. This method provides the most efficient energy system, best combination of equipment capacity and best operational planning for cooling, heating, and power simultaneously with respect to certain criteria such as energy consumption, CO₂ emission, etc. Specifically for this paper, the authors apply this method to a sample building as a case study. The “Genetic Algorithms (GA)” optimization method, which can resolve nonlinear optimization problems, is adopted for this optimization analysis. Also its applicability is analyzed in a case study. In order to validate the accuracy of this method, the correct optimum solution based on comprehensive inquiries is also calculated. A comparison of the GA solution with the correct solution demonstrates fairly good agreement. The results show that the proposed method is sufficiently capable of determining the optimal design and has the potential to be applied to very complex energy systems with appropriate modifications.     

大底盘双塔楼结构刚度控制方法研究

结合成都某大厦结构设计，定量分析了大底盘双塔楼结构水平侧移的规律，从而提出对称大底盘双塔楼结构刚度控制的方法。经算例验证，其精度能满足工程要求。     

带转换层结构侧向刚度计算的规范方法研究

根据现行规范,楼层侧向刚度的计算方法有3种。3种刚度的概念不相同,计算结果的差异也较大。本文结合实际工程对3种刚度计算方法进行了定量分析和比较,在此基础上,明确了不同刚度计算方法的适用范围。     

A method for estimating changes in the visibility of land cover

An inventory of resources that includes the contribution made by land cover to the visual landscape can be used in monitoring and assessing the impacts of change in land cover on the visual landscape of an area. A method is presented for assessing the visual resources of the landscape as applied to a case study area in the western part of the proposed Cairngorm National Park in Scotland. The method is based upon measuring the extent of the land from which different land cover types may be visible, on a cell-by-cell basis, using high resolution Digital Elevation Models combined with interpreted land cover data as inputs. The results show a reduction in the overall contribution of scattered, natural woodland to the visual landscape, and an increase in the visual contribution of plantation woodland at the expense of heather moorland. The geographical distribution of the changes in visibility of land cover types is shown and the potential of the method for providing a spatial context for expressing the results of landscape preference modelling is discussed.     

肋环型索穹顶初始预应力分布的快速计算法

肋环型索穹顶是美国工程师Geiger根据Fuller的张拉整体结构思想开发的一种新型预张力结构,并最早应用在汉城奥运会的体操馆和击剑馆。考虑到该结构是一种轴对称结构,本文提出了确定初始预应力分布的快速计算法．该法从平面径向桁架节点平衡关系入手,推导了不设和设有内拉环的肋环型索穹顶预应力杆内力一般性的计算公式．对特定参数的索穹顶结构还给出了内力计算用表．通过本文提供的分析方法、计算公式和内力计算用表,可方便快速的确定肋环型索穹顶结构的初始预应力分布,为该类结构的进一步设计和力学性能分析提供基础．     

单桩竖向抗压刚度的集成刚度法

本文通过力学基本原理分析了文献[4]所述单桩竖向抗压刚度的集成刚度法的物理本质,验证了集成刚度法中力学概念的合理性,完善了计算公式中某些未确定参数的取值方法,以集成刚度法分别计算了科特迪瓦阿比让奥林匹克体育场、科特迪瓦阿比让VIRID集装箱码头轨道试验桩的单桩竖向抗压刚度kp,通过与工程桩静载检测数据直接计算所得kp相...     

A simple method for estimating energy saving in buildings

This paper introduces a method of selecting the most energy-saving heating system without resorting to too complex and heavy analysis requiring large computers.

The method described uses an imaginary ‘year’ of 52 days picked at random, to enable designers to calculate diary heating needs in the various cases to be considered.

In the paper the method is applied to a swimming pool for which several heating and management systems liable to be used are studied and compared.     

Lateral restraint forces in Z-section roof systems using the component stiffness method

The component stiffness method is a method to predict lateral restraint forces in roof systems supported by Z-sections. The method approximates a bay of Z-sections as a single degree of freedom system and uses a stiffness formulation to determine the contribution of the different components in the system to the resistance of lateral movement. The forces generated by the roof system requiring restraint are derived from mechanics.     

A data fusion scheme for building automation systems of building central chilling plants

Accurate and reliable building load measurement is essential for robust chiller sequencing control, building air-conditioning system performance monitoring and optimization. This paper presents a scheme adopting the data fusion technique to improve the quality of building cooling load measurement of building automation systems. The strategy uses two types of measurement information on the cooling load, i.e., “direct measurement” of building cooling load, which is calculated directly using the differential water temperature and water flow rate measurements, and “indirect measurement” of building cooling load, which is calculated using a model using the instantaneous chiller electrical power input. Capitalizing their own advantages and disadvantages, a data fusion algorithm is developed to merge these two types of data to remove outliers and system errors as well as to reduce the impacts of measurement noises. Meanwhile, a method is implemented to provide quantitative evaluation of the degree of reliability of the merged measurement. Validation of the data fusion algorithm is conducted using field data collected from a chiller plant in a high-rising building in Hong Kong.     

房屋框架抗震墙与底层侧移刚度比控制分析

结合工程实际中的一些问题和建筑抗震设计规范，提出了底层框架抗震墙砖房第二层与底层侧移刚度的控制措施指标和设计方法，达到合理布置抗震墙，减少底层的薄弱程度，提高底层框架房屋的抗震能力的目的。     

Analysis and design guidance for the lateral stiffness of bellows expansion joints

Thin-walled bellows expansion joints are frequently applied in piping systems for absorbing thermal and mechanical movement. There have been several failures in service due to the lateral buckling of bellows under pressure, the most notable case being the Flixborough disaster in 1974. The problem of bellows squirming, as the phenomenon is more commonly termed, was first investigated by the Dutch engineer J. A. Haringx in 1952. In the intervening years there has been little additional research carried out and consequently there is a paucity of experimental data and practical theories on the subject. The present paper offers guidance to avoid bellows squirming and provides the design engineer with simple procedures for evaluating the stability of a pressurised bellows subject to either small or large lateral displacements. Formulae are also presented in order to determine the strength of bellows supports which limit and control the amount of bellows movement in service.     

A method for reliability-based economic design of building structures

In limit states design codes for building structures, the load and resistance factors are derived based on a ‘;target’ reliability index, which is determined based on a code calibration process. It is not clear whether the target reliability index selected through the code calibration is optimal with respect to the cost, because through calibration the structural safety is achieved quantitatively while the economic aspects are only considered qualitatively. The intention of the present paper is to formulate a basic approach to reliability-based economic design, based on structural reliability theory. The focus of the paper is to derive an analytical solution to optimized reliability index. A parametric study is conducted for sensitivity analysis of the optimal reliability index to different variables. Finally, the application of the solution to design codes, i.e. determining load and resistance factors in design formulae, is outlined.

Dans les codes de conception d'états limite se rapportant à la construction des structures de bâtiments, la charge et les facteurs de résistance reposent au départ sur un index de fiabilitié ‘cible’, qui est basé sur un processus de calibrage de code. Il n'est pas possible de savoir si l'index de fiabilitié cible choisi par le calibrage de code est optimal en ce qui concerne le coût parce que lors du calibrage, la sécurité structurelle est évaluée de façon quantitative. L'objectif de cet article est de formuler une appréciation de référence sur la conception reposant sur la fiabilité économique, basée sur la théorie de fiabilité structurelle; le point fort de ce texte est de trouver une solution analytique afin d'optimiser l'index de fiabilité. Une étude paramétrique est conduite pour analyser la sensibilité de la fiabilitié optimale de l'index par rapport aux diffeérentes variables. Au total, est proposée une solution consistant à concevoir des codes, c'est-à-dire la détermination de la charge et des facteurs de résistance sous l'aspect de formules.