Periodica Polytechnica Civil Engineering最新文献_第6页

SEM Image-based Porosity Analysis of Fire Damaged High Strength Concrete 基于扫描电子显微镜图像的火损高强度混凝土孔隙率分析

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-12 DOI: 10.3311/ppci.22917

Diana Andrushia, N. Anand, É. Lublóy, M. Naser, B. Kanagaraj

引用次数: 0

A Comprehensive Investigation of Performance Characteristics, Mechanical Properties and Durability Parameters of Self-compacting Concrete Containing Iron Slag as Coarse Aggregate 含铁矿渣粗集料的自密实混凝土性能特点、机械特性和耐久性参数的综合研究

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-03 DOI: 10.3311/ppci.22846

Ali Poornamazian, Mohsen Izadinia

{"title":"A Comprehensive Investigation of Performance Characteristics, Mechanical Properties and Durability Parameters of Self-compacting Concrete Containing Iron Slag as Coarse Aggregate","authors":"Ali Poornamazian, Mohsen Izadinia","doi":"10.3311/ppci.22846","DOIUrl":"https://doi.org/10.3311/ppci.22846","url":null,"abstract":"In this paper, iron slag is used as partial coarse aggregate substitution in Self-compacting concrete (SCC). The SCC samples tests were conducted after 28 days of water curing for samples with 0%, 10%, 20%, 30%, 40%, 50%, and 60% iron slag as coarse aggregate substitutes. This paper evaluates slump flow, V-funnel, L-box, compressive strength, flexural strength, splitting tensile strength, surface water absorption, capillary water absorption, electrical resistance, acid resistance, and ultrasonic pulse velocity (UPV) of concrete samples. Furthermore, scanning electron microscopy (SEM) of samples was investigated for evaluating cement paste microstructure. Samples containing 20%, 60%, and 60% iron slag as coarse aggregate substitute have higher compressive, flexural, and splitting tensile strength than control samples (about 18.4%, 28.6%, and 16.9% higher, respectively). In addition, using 10%, 20%, 30%, and 40% iron slag as coarse aggregate increased the compressive strength. Moreover, incorporating iron slag as a coarse aggregate decreased the mass loss of samples which were exposed to the acid environment compared to control specimens. Using iron slag as partial coarse aggregate substitution reduced the porosity of the cement matrix compared to control samples (based on SEM images).","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of Breakpoint Chlorination Technologies for Drinking Water Treatment: a Hungarian Case Study 饮用水处理断点氯化技术的优化：匈牙利案例研究

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-03 DOI: 10.3311/ppci.22760

D. Laky, Souha Neguez

{"title":"Optimization of Breakpoint Chlorination Technologies for Drinking Water Treatment: a Hungarian Case Study","authors":"D. Laky, Souha Neguez","doi":"10.3311/ppci.22760","DOIUrl":"https://doi.org/10.3311/ppci.22760","url":null,"abstract":"Ammonium ion is one of the major pollutants found in drinking water sources in Hungary, especially in deep aquifers. under oxidative conditions, ammonium can transform into nitrite ions in the water system, posing potential health risks. In Hungary mostly biological process or breakpoint chlorination are used to eliminate ammonium ion from raw water during the drinking water treatment process. When breakpoint chlorination is applied, harmful by-products are formed. Trihalomethanes concentrations have long been regulated in Hungary, therefore during the design and optimization of the breakpoint technologies trihalomethane concentrations have been considered. However, haloacetic acids (HAA5) and chlorate ion have been recently regulated in accordance with EU Directive 2020/2184. Chlorate is a by-product that appears in treated water when sodium hypochlorite is used in breakpoint chlorination.Experiments were carried out at four Hungarian case study areas to determine the optimal strategy for breakpoint chlorination: applying higher chlorine dosages with lower contact times, or lower chlorine dosages with higher contact times. The investigations concluded that the preferable dosing strategy is to use lower chlorine concentrations and longer contact times. This approach reduces chemical demand (cost-effective) and has a neutral effect on THMs formation. it can be concluded that when the raw water contains ammonium ion concentrations above 0.5 mg/l, the use of sodium hypochlorite may raise concerns due to elevated chlorate ion levels in the treated water, particularly during summer. Further research is required to expand the optimization strategy, considering not only ammonium and trihalomethane concentrations but also chlorate concentrations.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"105 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probabilistic Seismic Performance Assessment of Tall RC Special Moment-resisting Frame Buildings Equipped with Buckling-restrained Braces under Near-field Excitations 近场激励下配备屈曲约束支撑的高层 RC 特殊力矩抵抗框架建筑的概率地震性能评估

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-03 DOI: 10.3311/ppci.20914

Ali Zarif Moghadam Basefat, H. Pahlavan, Jalil Shafaie

{"title":"Probabilistic Seismic Performance Assessment of Tall RC Special Moment-resisting Frame Buildings Equipped with Buckling-restrained Braces under Near-field Excitations","authors":"Ali Zarif Moghadam Basefat, H. Pahlavan, Jalil Shafaie","doi":"10.3311/ppci.20914","DOIUrl":"https://doi.org/10.3311/ppci.20914","url":null,"abstract":"Many tall buildings have already been constructed near faults throughout the world, several of which have sustained casualties and economic losses during strong ground motions. This study investigates the effect of near-fault excitations on the vulnerability of tall, reinforced concrete (RC) special moment-resisting frame (SMRF) buildings equipped with buckling-restrained braces (BRBs) using seismic fragility curves. After attaining the structure’s response modification factor (R), three-dimensional (3D) models of 15-, 25- and 35-story frames were developed by the OpenSees software according to the Iranian code provisions. Thus, the seismic response of the elements was obtained. Subsequently, incremental dynamic analysis (IDA) was conducted by selecting a suitable number of compatible accelerograms in two near-field and far-field groups. Considering the maximum story drift as the demand parameter and selecting the interstory drift ratios (IDR) for the slight, moderate, extensive, and complete collapse seismic performance levels proposed by Hazus, IDA curves were plotted. Then, the seismic fragility curves were produced using the structural reliability relations. The median fragility at complete collapse damage level reduced from 0.73g, 0.62g, and 0.61g to 0.68g, 0.59, and 0.57g for the 15-, 25, and 35-story near-field and far-field earthquake models, respectively. This was attributed to increasing vulnerability and seismic fragility of the structures as a result of both height increase and distance reduction from fault. Based on the results, the most vulnerable structure, i.e., the 35-story near-fault model, experienced a 40, 17, 18, and 6% increase in median fragility at slight, moderate, extensive, and complete collapse damage levels, respectively.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"83 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139388087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Substructure-based Model Updating Method to Damage Detection for Large-scale Structures 基于下部结构的大型结构损伤检测模型更新方法

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-03 DOI: 10.3311/ppci.23010

Jiexin Yu, Wei Lin, Xin Chen, Benfei Xie

{"title":"A Substructure-based Model Updating Method to Damage Detection for Large-scale Structures","authors":"Jiexin Yu, Wei Lin, Xin Chen, Benfei Xie","doi":"10.3311/ppci.23010","DOIUrl":"https://doi.org/10.3311/ppci.23010","url":null,"abstract":"The health monitoring and damage detection of structures are major scientific issues that the civil engineering discipline, which made great achievements in the 20th century, has bequeathed to the 21st century. Despite the installation of health monitoring systems in many large structures, implementing damage detection through finite element model updating is often time-consuming or even infeasible due to the size of the model and the presence of numerous uncertain parameters. To address this issue, this paper proposes a substructure-based model updating method. The entire structure is divided into substructures with reduced degrees of freedom, allowing for the simplification of the motion equation by employing only a small number of low-order modes from each substructure. Consequently, the analysis scale of the structure is effectively reduced. The discarded higher modes are compensated by residual modes to ensure the accuracy of structural response and sensitivity. Subsequently, a damage identification program substructure-based model updating is developed, which is applied to component mode synthesis and damage identification for large structures. By precisely detecting damage in critical areas, accurate diagnosis and evaluation of the global structural safety are achieved. The results validate the implementation, computational efficiency, and accuracy of the proposed substructure-based model updating method. This approach shifts the focus from model updating of the entire structure to model updating of substructures, with the aim of fundamentally resolving the technical challenge of accurate damage detection of large and complex structures. Furthermore, it provides theoretical support for the practical application of damage detection in large civil structures.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"39 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sustainable Concrete: Exploring Fresh, Mechanical, Durability, and Microstructural Properties with Recycled Fine Aggregates 可持续混凝土：探索再生细骨料的保鲜、机械、耐久性和微观结构特性

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-03 DOI: 10.3311/ppci.22711

Harish Panghal, Awadhesh Kumar

{"title":"Sustainable Concrete: Exploring Fresh, Mechanical, Durability, and Microstructural Properties with Recycled Fine Aggregates","authors":"Harish Panghal, Awadhesh Kumar","doi":"10.3311/ppci.22711","DOIUrl":"https://doi.org/10.3311/ppci.22711","url":null,"abstract":"The growing construction industry and global population have led to increased demand for concrete, resulting in increased waste production. Recycling construction and demolition (C&D) waste as recycled fine aggregates (RFA) in concrete could help reduce waste and conserve natural resources. This research delves into the meticulous examination of particle packing density within specific cylindrical volumes under standard compacting efforts, elucidating an order of compressive strength. The study comprehensively explores various concrete properties, including workability, compressive strength, flexural strength, split tensile strength, drying shrinkage, electrical resistivity, rapid chloride penetration, and microstructural characteristics (analyzed through XRD, SEM, and EDAX). RFA particles, ranging from 0.15 to 4.75 mm, were employed as partial replacements for fine aggregates, with replacement percentages varying from 0% to 100% in increments of 25%. The empirical findings underscore that the incorporation of RFA significantly enhances concrete properties. However, it was observed that surpassing the optimum replacement percentage of 25% (RFA 25) adversely impacts the concrete’s strength and microstructure. Specifically, RFA 25 exhibited remarkable improvements, with a 14.75% increase in compressive strength, a 6.61% boost in flexural strength, and a 13.14% enhancement in split tensile strength compared to conventional concrete (RC). Furthermore, RFA 25 demonstrated a 4.16% increment in drying shrinkage, 17.65% higher electrical resistivity, and an 18.83% superior resistance to chloride penetration compared to RC. The analysis of XRD, SEM, and EDAX results elucidated that at lower replacement percentages, the pozzolanic reaction enhances strength by forming additional hydration products. Conversely, at higher replacement levels, strength diminishes.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"52 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Processes Towards Sedimentation around a Reed Island in a Shallow Lake 浅湖芦苇岛周围的沉积过程

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-02 DOI: 10.3311/ppci.22380

Mariann Biró-Szilágyi, Tamás Krámer, Krisztián Homoródi

{"title":"Processes Towards Sedimentation around a Reed Island in a Shallow Lake","authors":"Mariann Biró-Szilágyi, Tamás Krámer, Krisztián Homoródi","doi":"10.3311/ppci.22380","DOIUrl":"https://doi.org/10.3311/ppci.22380","url":null,"abstract":"There are many studies on the hydromorphological impacts of emergent aquatic vegetation, but many of these focus on gravity-driven flows in riverine or tidal environments. However, an added effect of emergent vegetation in lakes is that it reduces the main external force (wind) significantly and in a spatially coherent way. We performed long Monte Carlo simulations using a 2D hydrodynamic model and a spectral wind wave model to study resuspension dynamics around a 100-m-wide reed island in southern Lake Fertő/Neusiedl. Wave-current interaction, computed in a post-processing step, was found to enhance maximum bed shear stresses only on the leeward side of the reed island, and even there to a small extent. We have found evidence that the present bed topography is close to an equilibrium where simulated combined wave-current shear stresses have a reasonably uniform exceedance probability over the critical shear stress of the bed sediment. We also found that an artificially flattened lakebed around the reed island would start evolving towards the present bed topography and grain size distribution (both of which were surveyed in the field). Despite the limitations of our modelling framework, our results illustrate the importance of how wind climate is translated to an uneven distribution of sediment entrainment around the reed island, explaining tendencies of sediment accumulation and sorting. Our results lead to a better understanding of the complicated processes involving interaction among wind, vegetation, circulation, wind waves, sediment and bathymetry.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"132 34","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shear Strength Evaluation of Concrete Beams with FRP Transverse Rebar 使用 FRP 横向钢筋的混凝土梁的抗剪强度评估

Periodica Polytechnica Civil Engineering Pub Date : 2024-01-02 DOI: 10.3311/ppci.22324

Gökhan Barış Sakcalı, İsa Yüksel

{"title":"Shear Strength Evaluation of Concrete Beams with FRP Transverse Rebar","authors":"Gökhan Barış Sakcalı, İsa Yüksel","doi":"10.3311/ppci.22324","DOIUrl":"https://doi.org/10.3311/ppci.22324","url":null,"abstract":"Rebar corrosion in traditional reinforced concrete (RC) components may lead to a decrease in service life and carrying capacity. This condition is one of the reasons of the growing popularity of Fiber Reinforced Polymer (FRP) rebars as a corrosion-resistant alternative, particularly in RC infrastructure projects. Because the material properties and behavior of FRP rebar are very different from conventional steel rebar, the calculations used for reinforced concrete with conventional steel reinforcement should be updated for this material. The aim of this study is to propose a new shear strength prediction model for RC beams with transverse steel rebar in order to calculate the shear strength of RC beams with FRP transverse rebar according to TS-500, which is the Turkish Building Code. To achieve this goal, Finite Element Method (FEM) models were created for 27 RC beams with FRP transverse rebars and 9 RC beams without transverse rebars. Furthermore, for RC beams with FRP transverse rebars, a prediction model has been developed. Additionally, 13 prediction models obtained from regulations or scientific studies were compared to the proposed prediction model using a database of 105 tests obtained from previous experimental studies. It was observed that the proposed prediction model provides more consistent results with the test database from the literature compared to the models suggested by other regulations or studies. Therefore, by modifying the shear strength relations recommended in TS-500 for RC beams with transverse steel rebar, they can also be applied to RC beams with transverse FRP rebars.","PeriodicalId":512221,"journal":{"name":"Periodica Polytechnica Civil Engineering","volume":"56 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139452760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0