Empirical modelling of shear strength of RC deep beams by genetic programming

This paper investigates the feasibility of using genetic programming (GP) to create an empirical model for the complicated non-linear relationship between various input parameters associated with reinforced concrete (RC) deep beams and their ultimate shear strength. GP is a relatively new form of artificial intelligence, and is based on the ideas of Darwinian theory of evolution and genetics. The size and structural complexity of the empirical model are not specified in advance, but these characteristics evolve as part of the prediction. The engineering knowledge on RC deep beams is also included in the search process through the use of appropriate mathematical functions.The model produced by GP is constructed directly from a set of experimental results available in the literature. The validity of the obtained model is examined by comparing its response with the shear strength of the training and other additional datasets. The developed model is then used to study the relationships between the shear strength and different influencing parameters. The predictions obtained from GP agree well with experimental observations.     

Effect of electricity tariff on the optimum insulation-thickness in building walls as determined by a dynamic heat-transfer model

Thermal insulation is one of the most effective energy-conservation measures in buildings. Despite the widespread use of insulation materials in recent years, little is known regarding their optimum thickness under dynamic thermal conditions. Insulated concrete blocks are among the units most commonly used in the construction of building walls in Saudi Arabia. Typically, the insulation layer thickness is fixed at a value in the range 2.5–7.5 cm, regardless of the climatic conditions, type and cost of insulation material, and other economic parameters. In the present study, a numerical model based on a finite-volume, time-dependent implicit procedure, which has been previously validated, is used to compute the yearly cooling and heating transmission loads under steady periodic conditions through a typical building wall, for different insulation thicknesses. The transmission loads, calculated by using the climatic conditions of Riyadh for a west-facing wall, are fed into an economic model in order to determine the optimum thickness of insulation (L_opt). The latter corresponds to the minimum total cost, which includes the cost of insulation material and its installation plus the present value of energy consumption cost over the lifetime of the building. The optimum insulation thickness depends on the electricity tariff as well as the cost of insulation material, lifetime of the building, inflation and discount rates, and coefficient of performance of the air-conditioning equipment. In the present study, the effect of electricity tariff on the computed optimum insulation thickness is investigated. Different average electricity tariffs are considered; namely, 0.05, 0.1, 0.2, 0.3 and 0.4 SR/kWh (designated as Cases 1–5, respectively; 1 US$ = 3.75 Saudi Riyals). Results using moulded polystyrene as an insulating material show that the values of L_opt are: 4.8, 7.2, 10.9, 13.7 and 16.0 cm for Cases 1–5. Under the conditions of optimal insulation thickness for each electricity tariff, Case 1 gives the lowest total cost of 17.4 SR/m², while Case 5 gives the highest total cost of 53.1 SR/m². Corresponding thermal performance characteristics in terms of yearly total and peak transmission loads, R-value, time lag and decrement factor are presented.     

当前宁波地区住宅产品可持续发展浅析

文章从居住社区的规划设计和建筑设计两方面以低能耗的角度分析了城市居住功能的分布、社区住宅建筑布局的合理性、社区景观设置的合理性以及停车、中水处理与被动式太阳能住宅建筑的相关先进生态理念,希望通过居住社区的生态可持续性设计改善社区的舒适性和能源的可持续性.     

高层建筑结构设计的分析判断与优化

对高层建筑设计而言,设计前期的初步结构方案需通过结构软件的计算分析,判断该方案是否正确与合理,从而对其进行有针对性的修改和优化。文章结合具体实例,介绍了分析判断计算结果的主要几项内容及可采取的相应优化措施,从而可以提高设计的准确性和工作效率。     

与环境友好的绿色建筑材料

实施绿色建筑的主要途径之一是开发和使用绿色建筑材料，使得建筑与人和环境的关系和谐融洽。本文介绍了建筑材料对环境和人类健康的不利影响，并对绿色建筑材料的设计和开发作了探讨。     

利用微机设计保护煤柱

根据保护煤柱设计原理 ,利用微机采用垂线法留设保护煤柱的数学模型、程序流程以及得到的算例结果。利用该方法 ,只要将有关资料输入计算机 ,就能快速准确地自动计算出煤柱角点坐标、煤柱面积和压煤量。     

多层砖砌体房屋震害分析及抗震措施

介绍了我国砖砌体房屋历年来遭受震害的程度以及砖砌体的抗震性能，针对一些震害现象，分别从建筑布置和抗震措施加强对砖砌体的抗震性能进行论述。     

现代智能建筑防雷措施浅析

主要介绍系统防雷技术的具体防护方法。包括电源系统、UPS电源系统、终端设备电源、通讯网络系统、电话线及专线、局域网线路、卫星接收天馈线的防护以及接地保护系统。     

电信建筑在岩溶发育地区的地基基础设计

结合新密电信综合生产楼工程和贵阳第二长途电信枢纽楼工程的设计，介绍在岩溶发育场地上，对浅层岩溶地基的处理方法及基础类型的选择思路。     

节能建筑中人体传热模型和计算公式

讨论人体新陈代谢发热率及其影响因素;论述节能建筑中舒适的环境温度、空气相对湿度、空气流速以及新鲜空气供给量的最佳值范围;同时考虑皮肤和肺部的显热散热和蒸发潜热散热,建立了传热模型,得出了计算公式。