SPF级实验动物房的压差控制及节能设计

结合SPF级实验用动物房的洁净空调设计实例,探讨了在满足工艺要求的前提下,采用三级压差控制和变风量系统所达到的理想的压力梯度及节能效果;实际工程测试数据表明,采用上述方法并结合BA技术,可实现系统运行自动控制和设计目标.     

深圳茂宝大厦边坡加固设计与施工

深圳茂宝大厦采用毛石砌筑的建筑边坡挡土墙,设计、施工以及周边环境等因素导致墙体出现鼓肚、开裂.为改善边坡的安全状况,消除隐患,采用对墙体灌浆、喷锚、预应力锚索和格构梁等综合加固方法.试验证明,采用多种方法对危险挡土墙进行加固是可行的,且节约了成本.     

高等院校教授委员会的构建

教授委员会是高等学校“教授治校”的重要体现,其设置和运行应当与一个国家的教育体制相适应,并应对国家的高等教育产生推动作用。通过对不同教育体制下的教授委员会的分析比对,提出了在高校构建“教授委员会”的架构形式和基本准则。     

速度脉冲型地震动瞬时输入能特性研究

近断层地震动最显著的特点是由方向性效应和滑冲效应引起的脉冲型地面运动。通过建立单自由度体系瞬时输入能计算模型,输入速度脉冲地震记录进行了弹塑性时程分析,计算出地震动对结构的瞬时输入能量,研究了具有速度脉冲型地震动这种荷载形式的瞬时输入能特性及与结构最大位移反应的关系。研究结果表明,对于12次强地震动中109条具有速度脉冲的地震记录,输入结构的最大瞬时输入能总处于速度脉冲发生位置,说明速度脉冲波形对地震动最大瞬时输入能具有决定作用,并由最大瞬时输入能量与结构最大位移反应的对应关系,验证了近断层地震动对结构的破坏作用与速度脉冲有关。此外,与无速度脉冲地震动相比,具有速度脉冲会增大长周期结构的瞬时输入能,并且输入结构的最大瞬时输入能随地面峰值速度(PGV)和峰值加速度(PGA)的比值增大而增大。     

不同旋转曲面网架搭接的结构设计

通过对江西新余文化健身中心训练馆网架的设计,对两个不同曲率的旋转曲面网架是否搭接计算进行论证,经过详细的计算比选,确定两网架应搭接计算,以达到受力合理、位移协调、经济美观的目的,且连接形式采用空间杆件连接为宜。同时介绍多义线旋转曲面网架的建模过程。     

水位变化对库区某岩质边坡的稳定性影响分析

三峡水库岩质边坡的结构十分复杂、所处的地质环境多样,极易发生失稳破坏。传统的极限平衡理论的分析方法在对岩质边坡的稳定性分析上存在一定的局限性,分析结果存在一定偏差。文章采用有限元强度折减法,分析了库水位变化及岸坡结构面宽度改变与边坡稳定性影响的关系。研究表明,库水位变动速度的增加和结构面宽度的增大都会使得岸坡稳定性降低,两者变化均存在一个临界值,当变化超过这一临界值时,滑动面由浅层向深层发展,安全系数骤降。     

硫酸盐侵蚀下轴心受压钢筋混凝土柱应力时变过程的数值分析

针对荷载和硫酸盐耦合作用过程中钢筋混凝土柱的应力分析问题,在已有混凝土内硫酸根离子扩散反应模型的基础上,进一步给出了硫酸盐侵蚀引起的混凝土损伤程度与硫酸根离子浓度及腐蚀时间之间的关系,建立了与损伤程度相关的混凝土腐蚀本构模型及轴压混凝土柱截面应力的计算方法,并通过数值模拟分析了柱截面内硫酸根离子传输、腐蚀损伤程度变化、截面应变和应力分布规律。结果表明:硫酸根离子浓度和混凝土损伤程度在柱截面内呈梯度分布,且受二维交互效应的影响明显;随腐蚀时间的增加,截面损伤区逐渐向内移动且其宽度增加,而混凝土应力在损伤区呈先增加后逐渐降低、在未损伤区基本呈线性增加的趋势。硫酸盐侵蚀过程中,轴压混凝土柱截面应力发生了明显的重分布现象。     

A Bayesian Network model for predicting cooling load of commercial buildings

Cooling load prediction is indispensable to many building energy saving strategies. In this paper, we proposed a new method for predicting the cooling load of commercial buildings. The proposed approach employs a Bayesian Network model to relate the cooling load to outdoor weather conditions and internal building activities. The proposed method is computationally efficient and implementable for use in real buildings, as it does not involve sophisticated mathematical theories. In this paper, we described the proposed method and demonstrated its use via a case study. In this case study, we considered three candidate models for cooling load prediction and they are the proposed Bayesian Network model, a Support Vector Machine model, and an Artificial Neural Network model. We trained the three models with fourteen different training data datasets, each of which had varying amounts and quality of data that were sampled on-site. The prediction results for a testing week shows that the Bayesian Network model achieves similar accuracy as the Support Vector Machine model but better accuracy than the Artificial Neural Network model. Notable in this comparison is that the training process of the Bayesian Network model is fifty-eight times faster than that of the Artificial Neural Network model. The results also suggest that all three models will have much larger prediction deviations if the testing data points are not covered by the training dataset for the studied case (The maximum absolute deviation of the predictions that are not covered by the training dataset can be up to seven times larger than that of the predictions covered by the training dataset). In addition, we also found the uncertainties in the weather forecast significantly affected the accuracy of the cooling load prediction for the studied case and the Support Vector Machine model was more sensitive to those uncertainties than the other two models.     

Selection of risk response actions with consideration of secondary risks

Secondary risk in project risk management refers to the risk that arises as a direct result of implementing a risk response action (RRA). It is important for project managers (PMs) to consider the effects caused by the secondary risks in the process of RRA selection. The purpose of this paper is to propose an optimization method to address the problem of selecting risk response actions (RRAs) with consideration of secondary risk which is seldom considered in the existing studies. The optimization model aims to minimize the total risk costs with time constraint being placed on the project makespan. By solving the model, an optimal set of RRAs along with the earliest start time for each activity can both be obtained. The results show that secondary risk plays an important role in the process of RRA selection. Project managers should allocate more budget for responding the project risk when the secondary risk is considered, and consider all factors relating to both time and cost so as to select appropriate RRAs to mitigate primary risk and secondary risk.     

基于钢结构厂房事故的破损与原因分析

通过收集大量的事故资料,总结出钢结构厂房屋盖系统、吊车梁系统和柱子的破损现象、位置及原因,总结经验教训,为建筑物的安全提供保证。