Periodica Polytechnica-Civil Engineering最新文献_第9页

Analysis of the Shear Stress State at the Native Material/Repair Material Interface in Cooling Towers 冷却塔原生材料/修复材料界面剪应力状态分析

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-02-02 DOI: 10.3311/ppci.20731

R. Kutyłowski

引用次数: 0

Building Maps Using Monocular Image-feeds from Windshield-mounted Cameras in a Simulator Environment 在模拟器环境中使用安装在挡风玻璃上的摄像机的单目图像馈送构建地图

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-02-01 DOI: 10.3311/ppci.21500

M. Szántó, S. Kobál, L. Vajta, Viktor Győző Horváth, J. Lógó, Á. Barsi

{"title":"Building Maps Using Monocular Image-feeds from Windshield-mounted Cameras in a Simulator Environment","authors":"M. Szántó, S. Kobál, L. Vajta, Viktor Győző Horváth, J. Lógó, Á. Barsi","doi":"10.3311/ppci.21500","DOIUrl":"https://doi.org/10.3311/ppci.21500","url":null,"abstract":"3-dimensional, accurate, and up-to-date maps are essential for vehicles with autonomous capabilities, whose functionality is made possible by machine learning-based algorithms. Since these solutions require a tremendous amount of data for parameter optimization, simulation-to-reality (Sim2Real) methods have been proven immensely useful for training data generation. For creating realistic models to be used for synthetic data generation, crowdsourcing techniques present a resource-efficient alternative. In this paper, we show that using the Carla simulation environment, a crowdsourcing model can be created that mimics a multi-agent data gathering and processing pipeline. We developed a solution that yields dense point clouds based on monocular images and location information gathered by individual data acquisition vehicles. Our method provides scene reconstructions using the robust Structure-from-Motion (SfM) solution of Colmap. Moreover, we introduce a solution for synthesizing dense ground truth point clouds originating from the Carla simulator using a simulated data acquisition pipeline. We compare the results of the Colmap reconstruction with the reference point cloud after aligning them using the iterative closest point algorithm. Our results show that a precise point cloud reconstruction was feasible with this crowdsourcing-based approach, with 54% of the reconstructed points having an error under 0.05 m, and a weighted root mean square error of 0.0449 m for the entire point cloud.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87175244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Size Effect on Flexural and Fracture Properties of Polypropylene Fiber-reinforced Engineered Cementitious Composite 聚丙烯纤维增强工程胶凝复合材料弯曲断裂性能的尺寸效应

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-30 DOI: 10.3311/ppci.21155

Alireza Hosseini Mehrab, Seyedmahdi Amirfakhrian, M. Esfahani

{"title":"Size Effect on Flexural and Fracture Properties of Polypropylene Fiber-reinforced Engineered Cementitious Composite","authors":"Alireza Hosseini Mehrab, Seyedmahdi Amirfakhrian, M. Esfahani","doi":"10.3311/ppci.21155","DOIUrl":"https://doi.org/10.3311/ppci.21155","url":null,"abstract":"The size effect on flexural properties and fracture behavior of polypropylene fiber-reinforced engineered cementitious composite (PPFECC) containing local waste materials was investigated. Geometrically similar notched beams with dimensions of 190 × 70 × 70 mm (small), 380 × 70 × 140 mm (medium), and 760 × 70 × 280 mm (large) were tested using three-point bending to study the size effect on flexural properties, toughness, and fracture behavior in PPFECC and the influence of tensile ductility of PPFECC on the size effect parameter. Two PPFECC mixtures containing 1% (PPFECC1) and 2% (PPFECC2) volume fraction of polypropylene fibers were prepared. The results indicated clear size effect on ductility, flexural strength, normalized deflection, normalized toughness, and fracture energy for both PPFECCs. The flexural properties and fracture behavior in PPFECC1 were more sensitive to the size effect parameter due to its lower tensile ductility compared to PPFECC2. Moreover, according to Bažant’s size effect curve, the behavior of notched beams in PPFECC2 with higher tensile ductility was closer to the strength criterion compared to PPFECC1.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90453204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stabilization of Zeolite and Bentonite with Sewage Sludge Ash 沸石和膨润土在污泥灰中的稳定作用

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-30 DOI: 10.3311/ppci.21522

Özgür Yıldız, Çiğdem Ceylan

{"title":"Stabilization of Zeolite and Bentonite with Sewage Sludge Ash","authors":"Özgür Yıldız, Çiğdem Ceylan","doi":"10.3311/ppci.21522","DOIUrl":"https://doi.org/10.3311/ppci.21522","url":null,"abstract":"In this study, it is aimed to evaluate the wastewater sludge supplied locally at 100 tons/day in the investigation area. In this context, the geotechnical properties of bentonite, zeolite-type clays and sands, which are common in the investigation area, were determined by mixing with sewage sludge ash (SSA) in specified ratios. Grain size distribution and specific gravity of pure materials and mixtures were determined. Direct shear tests, permeability tests, consistency limits tests, modified proctor tests and PH determination tests were performed with the mixtures. Soils were mixed with 0.5, 7.5, 10 and 12.5 percent SSA in order to determine the physical, chemical and mechanical properties. Mixtures of sand with 40% bentonite (i.e., BS40) and sand with 40% zeolite (i.e., ZS40) were used as host materials for SSA inclusion. As a result of extensive laboratory studies, it was observed that the engineering properties of the specimens changed significantly as a result of the 7.5% and 12.5% mixture of SSA. BS40/SSA7.5 and ZS40/SSA12.5 samples from the mixtures reached 83 kPa and 80 kPa maximum shear strength under 200 kPa normal pressure. The maximum unit weight of specimens was achieved by BS40/S5 and ZS40/S5 specimens as 1.72 and 1.82 g/cm3, respectively. With the addition of SSA, the hydraulic permeability of the mixtures decreased to an order of 10E–8 (cm/s) for BS40/SSA12.5 and ZS40/12.5 specimens. Experimental studies have provided significant engineering and environmental benefit in the evaluation of sewage sludge ash, which is inevitable in residential areas.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88015861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust Vibration Output-only Structural Health Monitoring Framework Based on Multi-modal Feature Fusion and Self-learning 基于多模态特征融合和自学习的鲁棒振动输出结构健康监测框架

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-26 DOI: 10.3311/ppci.21756

Hung V. Dang, Truong-Thang Nguyen

{"title":"Robust Vibration Output-only Structural Health Monitoring Framework Based on Multi-modal Feature Fusion and Self-learning","authors":"Hung V. Dang, Truong-Thang Nguyen","doi":"10.3311/ppci.21756","DOIUrl":"https://doi.org/10.3311/ppci.21756","url":null,"abstract":"Output-only structural health monitoring is a highly active research direction because it is a promising methodology for building digital twin applications providing near-real-time monitoring results of the structure. However, one of the technical bottlenecks is how to work effectively with multiple high-dimensional vibration signals. To address this question, this study develops a two-stage data-driven framework based on various advanced techniques, such as time-series feature extractions, self-learning, graph neural network, and machine learning algorithms. At first, multiple features in statistical, time, and spectral domains, are extracted from raw vibration data; then, they subsequently enter a graph convolution network to account for the spatial correlation of sensor locations. After that, the high-performance adaptive boosting machine learning algorithm is leveraged to assess structures' health states. This method allows for learning a lower-dimensional yet informative representation of vibration data; thus, the subsequent monitoring tasks could be performed with reduced time complexity and economical computational resources. The performance of the proposed method is qualitatively and quantitatively demonstrated through two examples involving both numerical and experimental structural data. Furthermore, comparison and robustness studies are carried out, showing that the proposed approach outperforms various machine learning/deep learning-based methods in terms of accuracy and noise/missing-robustness.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91364983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Accuracy Assessment of “Step-by-Step” Simulation Modeling Method for Rock Breaking by TBM Disc Cutters Assisted with Laser 激光辅助下TBM盘式切割机破岩“分步”仿真建模方法的精度评价

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-23 DOI: 10.3311/ppci.21569

Kui Zhang, Ming Kuang, Jin-gang Liu, Xuejun Zheng, Shuo Qiao

{"title":"Accuracy Assessment of “Step-by-Step” Simulation Modeling Method for Rock Breaking by TBM Disc Cutters Assisted with Laser","authors":"Kui Zhang, Ming Kuang, Jin-gang Liu, Xuejun Zheng, Shuo Qiao","doi":"10.3311/ppci.21569","DOIUrl":"https://doi.org/10.3311/ppci.21569","url":null,"abstract":"Rock breaking by laser-assisted disc cutters is a novel high-efficiency rock breaking mode that combines mechanical stress induced by the disc cutters with thermal cracking by laser. This paper presented a “step-by-step” simulation modeling concept, and conducted an in-depth study on potential influencing factors of simulation accuracy at each key step. First, the prediction accuracy of laser holes in laser drilling simulation was discussed. Second, the SHPB simulation and experiment were carried out to evaluate the accuracy of the selected material constitutive model in simulating the dynamic fracture damage of rock. Then, taking the laser-assisted rock-penetrating process of the scaled disc cutter as an example, the simulation prediction accuracy of rock-breaking by the disc cutter was analyzed. Finally, the simulation and experiment of laser-assisted disc cutter penetration into rock was carried out, and then the feasibility of the “step-by-step” concept was analyzed. The results show that: (1) in the laser drilling simulation, the predicted accuracy of laser hole size is higher when the power is low; with the laser power increases, the large amount of glass glaze will affect the subsequent modeling accuracy; (2) the HJC model can be used to simulate the transient nonlinear fracture damage behavior of granite; (3) the damage morphology of the granite obtained by the penetration simulation is highly similar to the experimental results, and the load curve should be corrected by the peak point fitting method. The results show the application prospects of the proposed numerical modeling method in future laser-assisted TBM tunnelling.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85210106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Residual Durability Performance of Glass Fiber Reinforced Concrete Damaged by Compressive Stress Loads 压应力作用下玻璃纤维混凝土的剩余耐久性研究

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-19 DOI: 10.3311/ppci.21387

M. Yıldırım, Hacer BİLİR ÖZHAN

{"title":"Residual Durability Performance of Glass Fiber Reinforced Concrete Damaged by Compressive Stress Loads","authors":"M. Yıldırım, Hacer BİLİR ÖZHAN","doi":"10.3311/ppci.21387","DOIUrl":"https://doi.org/10.3311/ppci.21387","url":null,"abstract":"Concrete is exposed to a variety of stresses throughout its service life, which can result in cracks and damage. The use of fibers in concrete mixtures is known to improve the mechanical and durability properties of the concrete. In this study, glass fiber-reinforced concrete cube specimens were produced and stressed at 70 and 90 percent of their maximum compressive strength. The effects of stress loading-induced cracks and glass fiber reinforcements on mechanical and durability properties of concrete specimens were investigated using UPV, capillary water absorption, acid effect, and high-temperature effect tests. Glass fibers increased compressive strength and reduced water absorption in specimens that were not stressed. On the other hand, glass fibers increased the durability of stressed specimens at both degrees of compressive load stress. The bridging effects of glass fibers reduced crack creation, resulting in improved UPV test results. Glass fibers did not dissolve in acid solution due to their chemical resistance, resulting in less weight loss and higher compressive strength in concrete specimens. In the high-temperature effect tests, decreasing compressive strength values were observed as the stress load and temperature levels increased. However, such reductions were lower for glass fiber reinforced concrete than for control concrete without glass fiber. As a result of the present findings, glass fiber reinforcements prevent stress-induced cracks, making the concrete more durable and stronger against external forces.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90879031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Determination of Reinforced Fly Ash Concrete Columns’ Resistance Using Nonlinear Models of Materials 用非线性材料模型确定加筋粉煤灰混凝土柱的阻力

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-18 DOI: 10.3311/ppci.20626

V. Dang, Vongchith Sykhampha, Truong-Thang Nguyen

{"title":"Determination of Reinforced Fly Ash Concrete Columns’ Resistance Using Nonlinear Models of Materials","authors":"V. Dang, Vongchith Sykhampha, Truong-Thang Nguyen","doi":"10.3311/ppci.20626","DOIUrl":"https://doi.org/10.3311/ppci.20626","url":null,"abstract":"This article introduces experimental and analytical studies on the resistance under eccentric loads of reinforced fly ash concrete (RFAC) columns, in which fly ash (FA) is used to partially replace ordinary Portland cement (OPC) with a by-mass ratio of 20%. Based on experimental results of concrete specimens with mean 28-day cylinder strength of 30 MPa, modifications on simplified bi-linear and tri-linear models of stress-strain relationships of OPC concrete specified in the Russian and Vietnamese design standards are proposed. These nonlinear deformation models are incorporated into an analytical approach to establish the resistance of RFAC columns in the form of interaction surface, associated with an assessment method for safety factor based on the principle of inverse distance weighted average (IDWA). Parameters of the proposed analytical approach are determined by test results obtained from eight RFAC column specimens having 150 × 200 (mm) rectangular cross-section, 1600 mm-height, and 4Φ14 longitudinal rebars with yield strength of 362.6 MPa. In the tests, the specimens were loaded with uniaxial eccentricities ranging from 0 to 80 mm until failed. It is shown that with ε’b1 = 0.0022 and kE = 0.91, the corresponding safety factors of bi-linear and tri-linear models validated for the tested specimens are conservative and nearest to unity, proving that the proposed analytical approach is capable of closely predicting the RFAC columns’ resistance.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89926237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Experimental Study of Axially Loaded Pile Group Near a Sloping Ground 坡地附近轴向荷载群桩试验研究

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-18 DOI: 10.3311/ppci.18334

Reza Alinejad, M. Bayat, B. Nadi, M. S. Pakbaz

{"title":"Experimental Study of Axially Loaded Pile Group Near a Sloping Ground","authors":"Reza Alinejad, M. Bayat, B. Nadi, M. S. Pakbaz","doi":"10.3311/ppci.18334","DOIUrl":"https://doi.org/10.3311/ppci.18334","url":null,"abstract":"Understanding the axial loading response of pile group located near the crest of the slope is of practical value to structural design. In this paper, a large-scale test setup (1.8 m × 0.90 m × 0.90 m) has been developed to investigate the response of pile group (2 × 2) located near the crest of the slope under axial loading. This paper presents a series of physical modelling tests performed to investigate the effects of slope angles, distance of the pile group from the slope crest, embedment length of the pile group and pile diameter on the axial loading response of pile groups. The results show that the response of pile group located near the crest of the slope approaches to the level ground condition with increasing edge distance from slope crest. In addition, the horizontal displacement of pile group towards the slope face increases with decreasing distance of pile group from the slope crest or embedded length of piles or with increasing slope angle. Furthermore, increasing pile diameter results in a low increase in the horizontal displacement for edge distances less than 3 dp (dp = pile diameter). However, the horizontal displacement is almost independent of pile diameter at edge distances greater than 3 dp. Higher embedded length results in the response of pile group approaches to the response of pile group located on the level ground at a shorter edge distance from the slope crest.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84200320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development Process of Workplace Mobility Planning in Three Pilot Locations 三个试点地区工作场所流动规划的发展过程

IF 1.8 4区工程技术

Periodica Polytechnica-Civil Engineering Pub Date : 2023-01-13 DOI: 10.3311/ppci.20485

D. Esztergár-Kiss

{"title":"Development Process of Workplace Mobility Planning in Three Pilot Locations","authors":"D. Esztergár-Kiss","doi":"10.3311/ppci.20485","DOIUrl":"https://doi.org/10.3311/ppci.20485","url":null,"abstract":"A prospective way to make transportation more sustainable is changing the commuters’ travel behavior, which can be realized by creating mobility plans for institutions. A new approach related to workplace mobility planning is developed in three pilot locations in Hungary. As a first step, a roadmap is established including current situation analysis as well as collecting potential measures, setting up a mobility team, and developing pilot actions. The paper presents the planning process taking several aspects, such as commitment, vision, stakeholders’ involvement, situation analysis, measure implementation, and recommendations, into account. In the process, several stakeholders are involved to provide useful inputs through online surveys, personal interviews, and focus group meetings. The pilot development process covers three institutions in three locations with such specific parameters as the size of the city, the number of employees, location, and accessibility. As a result, it is seen that most measures aim at cycling infrastructure development, bike fleet introduction, and electric charger deployment. The proposed process is easily transferable and applicable in any location and any institution. The results not only support the commuters but show a potential to serve long-term societal goals, as well.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87687593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0