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A Study on Dynamic Behavior of Natural Draft Cooling Tower Considering the Effect of Soil-Structure Interaction 考虑土-结构相互作用影响的自然通风冷却塔动力特性研究
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0047
Mahesh Kumar Chitrahalli Lingaraju, Shwetha Kotagi Girisha, Shanthappa Bhaktanakatte Channabasappa, Manjunatha Karigowda
Abstract In this present era, the technology in advanced construction has developed to a very large extent. Some parts of the constructions are still in the improving stage which includes Cooling tower Construction. Hyperbolic cooling towers are large, thin shell reinforced concrete structures which Contribute to power generation efficiency, reliability, and to environmental protection. Cooling towers use evaporation of water to eject heat from processes such as cooling the circulating water used in oil refineries and in power plants. Nowadays in many thermal power plants, we can see the Cooling tower. So, preserving this industrial structure is an effort to save the cooling tower from dangerous earthquakes. The present-day cooling towers are exceptional structures in view of their sheer size and complexities. Present paper deals with the study of dynamic response that is modal analysis, seismic analysis of the two different cooling towers varying the H/t ratio and thicknesses with fixity at the base boundary condition, and the soil is modelled as raft for the effect of soil-structure interaction using the direct approach. In this paper, hyperbolic cooling towers are modelled using Ansys software, which is a Finite element Software. Results show that the soil-structure interaction effect significantly modifies the earthquake behavior of Hyperbolic Cooling towers.
在当今时代,先进建筑技术得到了很大程度的发展。部分设施仍处于改进阶段,其中包括冷却塔的建设。双曲型冷却塔是一种大型薄壳钢筋混凝土结构,有利于发电效率、可靠性和环保。冷却塔利用水的蒸发从冷却炼油厂和发电厂的循环水等过程中排出热量。现在在许多火力发电厂,我们可以看到冷却塔。因此,保护这个工业结构是为了保护冷却塔免受危险地震的影响。当今的冷却塔就其庞大的规模和复杂程度而言,是一种特殊的结构。本文研究了两种不同冷却塔的动力响应,即模态分析和地震分析,并在基础边界条件下,采用直接法将土作为筏板模拟土-结构相互作用的影响。本文采用有限元软件Ansys对双曲型冷却塔进行建模。结果表明,土-结构相互作用对双曲型冷却塔的抗震性能有显著影响。
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引用次数: 0
Investigation of the Occurrence of Progressive Collapse in High-Rise Steel Buildings with Different Braced Configurations 不同支撑结构高层钢结构房屋连续倒塌的研究
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0048
H. Saberi, V. Saberi, Abbas Sadeghi, Abbas Pooyasefat, E. N. Farsangi
Abstract The progressive collapse phenomenon refers to a chain of damages in a structure where all or a large part of the structure is destroyed by an initial local collapse in it, which can lead to very disastrous results. Therefore, the prevention of progressive collapse has become a necessary action in the design and analysis of buildings and it is vital to investigate this topic more accurately. This study aims to present a proposed pattern in the configuration of braces at the height of a high-rise steel building for reducing the probability of progressive collapse. In this regard, the vertical displacement of 18-story structure with four scenarios of column removal and five concentric bracing patterns including V, Inverted V, X, discontinuous X-bracing at height, and a combination of Xbracing in the side spans and discontinuous X-bracing at height in the middle spans are investigated and compared. In this study, the Alternative Path Method (APM) is used based on the GSA guideline for the analysis of progressive collapse. The results of this research showed that the use of X-bracing in the side spans and discontinuous X-bracing in the middle spans in nonlinear static and dynamic analyses performed better in reducing the probability of progressive collapse than other bracing configurations. Finally, it is recommended to use discontinuous X-bracing at the height that would place the bracings in one direction and providing alternative paths for force transferring in the structure.
渐进性破坏现象是指结构的一系列损伤,其中结构的全部或大部分由结构的局部初始破坏而破坏,其后果是非常严重的。因此,防止连续倒塌已成为建筑设计和分析的必要措施,更准确地研究这一课题至关重要。本研究的目的是提出一种在高层钢结构建筑高度的支撑配置模式,以减少渐进倒塌的可能性。为此,对18层结构在V型、倒V型、X型、高度不连续X型支撑、侧跨X型支撑与中跨高度不连续X型支撑组合4种拆柱方案下的竖向位移进行了研究和比较。本文在GSA准则的基础上,采用可选路径法(APM)对连续塌陷进行分析。研究结果表明,在非线性静力动力分析中,侧跨采用x型支撑,中跨采用不连续x型支撑,能较好地降低连续倒塌的概率。最后,建议在高度处使用不连续的x形支撑,这将使支撑在一个方向上,并为结构中的力传递提供替代路径。
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引用次数: 1
Repair and Renovation of the Historic Church in Ruda Śląska After Many Failures Caused by Mining Exploitation 在因采矿开采而多次失败后,鲁达西隆斯卡历史教堂的修复和翻新
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0051
Ł. Drobiec
Abstract This paper describes a case of the church, which for nearly 70 years was exposed to the impact of 26 mining exploitations conducted under the church or very close to the church at different depths. These caused damage in the form of superficial cracks of vaults and walls as well as the loosening of the front layer of stone façade of towers. The construction has been preserved due to the continuous monitoring and numerous repairs and renovations. Currently, there is no mining exploitation under the church.
摘要本文描述了一个教堂的案例,在近70年的时间里,该教堂受到了在教堂下方或离教堂很近的不同深度进行的26次采矿开采的影响。这些造成了拱顶和墙壁表面裂缝的破坏,以及塔楼前立面石层的松动。由于不断的监测和多次的维修和翻新,该建筑得以保存。目前,教堂下没有采矿开采。
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引用次数: 1
Contracts’ Performance Measurement in Czech Construction Companies 捷克建筑公司的合同绩效衡量
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0058
P. Trtílek, T. Hanák
Abstract Performance measurement of construction contracts belongs to the crucial activities enabling the improvement of processes in a construction company. The main aim of this paper is to evaluate and analyse performance management practices applied by contractors in the Czech construction sector. Original data were collected using a questionnaire survey and quantified through relative frequency of occurrence. These data have been supplemented by interviews with experts in the field in order to assess the importance of the individual criteria and other relevant performance aspects. The main findings illustrate differences in approach with respect to company size, as well as the most frequently used performance indicators and criteria. The study also focused on the performance measurement of subcontractors and the factors influencing contract success. The results show that large companies have already developed elaborate measurement systems and have sufficient staff for this purpose. Companies in the Micro&Small category show worse measurement performance, mainly due to the lack of qualified staff.
摘要施工合同的绩效衡量属于施工企业改进流程的关键活动。本文的主要目的是评估和分析捷克建筑行业承包商采用的绩效管理做法。原始数据是通过问卷调查收集的,并通过相对发生频率进行量化。这些数据得到了该领域专家访谈的补充,以评估个人标准和其他相关业绩方面的重要性。主要调查结果表明,在公司规模以及最常用的绩效指标和标准方面,方法存在差异。研究还重点关注了分包商的绩效衡量以及影响合同成功的因素。结果表明,大公司已经开发出了精细的测量系统,并为此配备了足够的员工。微型和小型公司的衡量表现较差,主要是由于缺乏合格的员工。
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引用次数: 2
Accuracy Characteristics of the Selected Diagnostics Methods and the Adjustment of Geodetic Observations 所选诊断方法的精度特征及大地观测平差
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0055
Martyna Kulupa, Paulina Magda, M. Mrówczyńska
Abstract The article presents the results of the adjustment of the experimental horizontal geodetic network using the classical method and the estimation of strengths in identifying observations with gross error and analyzing the accuracy of the obtained results. The presented analyses were made considering the possibility of their use in implementation networks and measurement and control networks used for monitoring building structures. The paper’s subject was a horizontal network established on the Morasko campus (Poznań). While creating it, the practical needs and economics of measurements were taken into account. The obtained results of numerical analyzes confirmed the benefits of using the methods of estimating strengths in the equalization process, which give satisfactory results in the case of outliers.
摘要本文介绍了用经典方法平差实验水平大地测量网的结果,并利用强度估计方法识别观测值的粗误差,分析所得结果的精度。提出的分析是考虑到它们在用于监测建筑结构的实施网和测控网中使用的可能性。这篇论文的主题是在Morasko校园(波兹纳斯)建立的一个横向网络。在创建它时,考虑了实际需要和测量的经济性。数值分析的结果证实了在均衡过程中使用强度估计方法的优越性,在存在异常值的情况下得到了满意的结果。
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引用次数: 1
Improvement of the Mechanical Behavior of Composite Materials with Different Binders Based on Local Plant Fibers Alfa and Diss 基于本地植物纤维Alfa和Diss的不同粘结剂对复合材料力学性能的改善
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0053
Zohra Belkhir, M. Merzoud
Abstract Concerned about the environmental and economic impact, composite materials are increasingly used in the construction sector. Indeed, the use of plant fibers as reinforcement in construction materials have been the subject of several researches in recent years; the main motivation is the weight gain combined with high mechanical characteristics. The objective of this research concerns the study of the physicomechanical properties of composite materials with cement and clay matrices reinforced with Alfa and Diss fibers with dimensions ranging from 2 to 8 cm. This involves evaluating the performance of these materials according to the formulation, for a volume ratio (Alfa or Diss / Matrix fibers equal to 4), using dry fibers and pre-wetted fibers. The study of the mechanical properties showed a drop of the performance for both compression and bending strength compared to the reference material without adding fibers (cement or clay paste). It should be noted that the best mechanical performance is obtained for the case of composites materials with cementitious matrix with pre-wetted fibers. On the other hand, in the case of composites with clayey matrices, pre-wetting does not improve the mechanical characteristics. It is also noted that the best dimensions of fibers which improve the mechanical characteristics in bending are generally 6 cm for composites with a clay matrix and between 2 and 4 cm for cementitious composites. In all cases, the fibers in composite materials with cement or clay matrix create a bridging effect, making it possible to limit the progression of cracks during loading. This phenomenon gives to the various composite materials a ductile behavior.
摘要考虑到对环境和经济的影响,复合材料越来越多地用于建筑行业。事实上,近年来,在建筑材料中使用植物纤维作为增强材料已经成为一些研究的主题;主要动机是体重增加与高机械特性相结合。本研究的目的是研究尺寸为2至8cm的Alfa和Diss纤维增强水泥和粘土基质复合材料的物理力学性能。这包括根据配方评估这些材料的性能,体积比(Alfa或Diss/基质纤维等于4),使用干纤维和预润湿纤维。力学性能的研究表明,与不添加纤维的参考材料(水泥或粘土浆)相比,压缩和弯曲强度的性能都有所下降。应该注意的是,对于具有预润湿纤维的胶结基质的复合材料,获得了最佳的机械性能。另一方面,在具有粘性基质的复合材料的情况下,预润湿并不能改善力学特性。还应注意的是,对于具有粘土基质的复合材料,改善弯曲力学特性的纤维的最佳尺寸通常为6cm,而对于水泥基复合材料,纤维的最佳尺度在2~4cm之间。在所有情况下,具有水泥或粘土基质的复合材料中的纤维都会产生桥接效应,从而有可能限制加载过程中裂纹的发展。这种现象使各种复合材料具有延性。
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引用次数: 1
Geometry Optimalization of the Ventilated Insulating Panel 通风隔热板的几何优化
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0050
A. Wójcik, Jakub Wójcik, Witold Grymin, P. Konca, D. Gawin
Abstract An EPS ventilated panel, which may be applied as an external insulation to humid walls, is investigated. Dimensions of the air channel sections have been determined using the Ansys software. Afterwards, the drying rate of the walls externally insulated with EPS, mineral wool and EPS ventilated panel has been compared using the WUFI software. The ventilated panel increases the drying rate when compared with the standard polystyrene panel and increases the heat loss through the wall by less than 20%.
摘要:研究了一种EPS通风板,它可以作为潮湿墙壁的外保温材料。利用Ansys软件确定了风道截面的尺寸。然后利用WUFI软件对EPS、矿棉和EPS通风板外保温墙体的干燥速率进行比较。与标准聚苯乙烯板相比,通风板提高了干燥速度,并使穿墙热损失增加不到20%。
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引用次数: 0
Identification of the Key Causes and Measures to Prevent Building Collapses in Nigeria 确定尼日利亚建筑物倒塌的主要原因和预防措施
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0049
Chiemezie Chisom Nwosu, K. Zima
Abstract Buildings collapse in the Nigerian major urban cities continues to engender an excessive number of fatalities, injuries and property damage. The collapse of building infrastructure, though prominent in developing economies, is a worldwide issue. Building developments collapse at the construction stages and in some cases after commissioning. Examples abound in recent times in Abuja and Lagos. The major problem is the unquantifiable resources wasted when building construction development collapses. If the answer to this endemic problem is proper project management, it becomes imperative to institutionalize its activities in Nigeria. Building Collapse is an occurrence that has been notorious over the decades. It is caused by many factors which have their great impact on the lives and properties of man. This study reviews current causes in the building industry. In view of this development, this study is aimed at demonstrating how real estate project management strategy helps in building collapse. Data from the primary source were basically from the designed instrument, which were distributed to the population of 100 professionals in the building industries. In this paper, it was concluded that the key causes of building collapse are weak/faulty foundations, inefficient stringent quality control in material utilization, and management, boycotting the professionals, absence of proper site investigation, the absence of proper site investigation and the engagement of inexperienced personnel. The aim of the study was to identify the factors influencing the occurrence of construction disasters in Nigeria in order to prevent them in the future. However, the analysis of the results gathered, reveal that, there was variance in opinions, as to the causes of building collapse among professionals in an attempt to exonerate themselves from the blame for building collapse. These were classified as the areas in the building sector that were prone to building collapse. Therefore, this study claims that the above-listed causes of building collapse are predominant in the Nigerian construction industry.
尼日利亚主要城市的建筑物倒塌继续造成大量人员伤亡和财产损失。基础设施建设的崩溃,虽然在发展中经济体很突出,但却是一个全球性的问题。楼宇发展项目在建造阶段或在某些情况下在投入使用后倒塌。最近在阿布贾和拉各斯的例子比比皆是。主要问题是建筑建设发展崩溃造成不可量化的资源浪费。如果解决这一地方性问题的办法是适当的项目管理,那么就必须使其在尼日利亚的活动制度化。几十年来,建筑物倒塌一直是臭名昭著的事件。它是由许多因素造成的,这些因素对人类的生活和财产有很大的影响。本研究回顾了目前建筑行业的原因。鉴于这一发展,本研究旨在展示房地产项目管理策略如何帮助建筑物倒塌。主要来源的数据基本上来自设计的工具,这些工具被分发给100名建筑行业的专业人员。本文认为,建筑物倒塌的主要原因是基础薄弱/缺陷、材料利用质量控制不严格、管理不善、抵制专业人员、缺乏适当的现场调查、缺乏适当的现场调查和缺乏经验的人员参与。该研究的目的是确定影响尼日利亚建筑灾害发生的因素,以便在未来预防它们。然而,对收集到的结果进行分析,发现专业人员对建筑物倒塌的原因存在分歧,试图为自己开脱责任。这些区域被归类为建筑部门中容易发生建筑物倒塌的区域。因此,本研究认为上述建筑物倒塌的原因在尼日利亚建筑业中占主导地位。
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引用次数: 0
The Application of Sentinel-2 Data for Automatic Forest Cover Changes Assessment – Białowieża Primeval Forest Case Study Sentinel-2数据在森林覆盖变化自动评估中的应用——Białowież原始森林案例研究
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0054
R. Pelc-Mieczkowska
Abstract Sentinel-2 mission, as a part of European Space Agency Earth Observation Program Copernicus, designed specifically for Earth surface observations provides images in 13 bands. That imaging is used to analyse many subject areas as Land monitoring, Emergency management, Security and Climate change. In the presented paper the application of Sentinel-2 data for automatic forest cover changes detection has been analysed. As input data, B02, B03, B04 and B08 bands have been used to compute Normalized Difference Vegetation Index (NDVI) and Enhanced Normalized Difference Vegetation Index (ENDVI). To track changes in the forest cover over the years, for each pixel the difference in the value of vegetation indices between consecutive years have been calculated. Then the threshold was set at the level of 0.15. The values of differences above the threshold mean a significant decrease in the quality of vegetation and may be considered areas of deforestation.
摘要哨兵2号任务是欧洲航天局地球观测计划哥白尼的一部分,专门为地球表面观测设计,提供了13个波段的图像。该图像用于分析土地监测、应急管理、安全和气候变化等许多主题领域。本文分析了Sentinel-2数据在森林覆盖变化自动检测中的应用。作为输入数据,B02、B03、B04和B08波段已被用于计算归一化差异植被指数(NDVI)和增强归一化差异植被指标(ENDVI)。为了跟踪森林覆盖率多年来的变化,对每个像素计算了连续年份之间植被指数值的差异。然后将阈值设置在0.15的水平。高于阈值的差异值意味着植被质量显著下降,可以被视为森林砍伐地区。
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引用次数: 0
Resistance to Seawater of a New Cement Mortar Based on Additions of Recycled Product 掺加再生产品的新型水泥砂浆的耐海水性能
IF 0.7 Q4 ENGINEERING, CIVIL Pub Date : 2021-12-01 DOI: 10.2478/ceer-2021-0060
R. Harbi, Riad Derabla, Z. Nafa
Abstract This paper aims to explore some sustainability indicators including mainly the resistance to seawater of mortars containing 5% kaolin filler in the sand and different types of ecoproducts as cement additions. To this end, an experimental study was carried out with the aim of evaluating the effects of three types of cement additions (glass powder (GP), metakaolin (MK) and brick waste (BW)) with contents of 5, 15 and 25% as well as binary and ternary combinations of these same additions. The results obtained made it possible to show the effectiveness of filler and cement additions (glass powder (GP) or / and metakaolin (MK) compared to brick waste (BW)) in improving the durability of mortars against aggressive agents such as seawater. In the end, the cement mortars made from 25% MK, 25% GP and this compound of 5% GP and 25% MK showed good resistance to attack by seawater.
摘要:本文旨在探讨砂中掺5%高岭土填料和不同类型生态产品作为水泥添加物的砂浆的耐海水性能等可持续发展指标。为此,开展了一项试验研究,旨在评估三种水泥添加物(玻璃粉(GP)、偏高岭土(MK)和废砖(BW))的效果,分别为5%、15%和25%,以及这些添加物的二元和三元组合。所获得的结果表明,填料和水泥添加剂(玻璃粉(GP)或/和偏高岭土(MK)与砖废料(BW)相比)在提高砂浆抗腐蚀性剂(如海水)的耐久性方面是有效的。结果表明,由25% MK、25% GP和5% GP、25% MK组成的水泥砂浆具有良好的耐海水侵蚀性能。
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引用次数: 1
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Civil and Environmental Engineering Reports
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