Acta Polytechnica最新文献_第5页

Application of strut-and-tie models for assessing RC half-joints not complying with current code specifications 杆系模型在评估不符合现行规范的钢筋混凝土半节点中的应用

IF 0.8

Acta Polytechnica Pub Date : 2022-12-31 DOI: 10.14311/ap.2022.62.0607

G. Kotsovou, E. Vougioukas, D. Cotsovos

{"title":"Application of strut-and-tie models for assessing RC half-joints not complying with current code specifications","authors":"G. Kotsovou, E. Vougioukas, D. Cotsovos","doi":"10.14311/ap.2022.62.0607","DOIUrl":"https://doi.org/10.14311/ap.2022.62.0607","url":null,"abstract":"The work described is concerned with an investigation of the effectiveness of the use of strut-and-tie models for the structural assessment of half joints. Such elements form a part of many existing bridges which, although not complying with current code specifications, have not as yet displayed any significant signs of distress in spite of the increase in traffic volume and loads over the years. The work is based on a comparative study of the predicted and experimentally established values of load-carrying capacity and location and causes of failure of half-jointed beams with reinforcement layouts that replicate those found in structures designed in accordance with previous code specifications. The results obtained show significant shortcomings of the assessment method as this is found not only to underestimate load-carrying capacity by a margin ranging between 40 % and 65 %, but also to often fail to identify the location and causes of failure. Therefore, there is a need for an alternative assessment method that will be based on concepts capable of both providing a realistic description of structural-concrete behaviour and identifying the causes of failure leading to the loss of load-carrying capacity.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49042845","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

Study of surface roughness with MHD and couple stress fluid on porous curved annular plates 多孔弯曲环形板表面粗糙度的MHD和耦合应力流体研究

IF 0.8

Acta Polytechnica Pub Date : 2022-12-31 DOI: 10.14311/ap.2022.62.0574

Salma Alla Baksh, Hanumagowda Bannihalli Naganagowda

引用次数: 1

Conversion of units of length from the Czech state standard to the geodetic baseline Javoriv 将捷克国家标准的长度单位转换为Javoriv大地测量基线

IF 0.8

Acta Polytechnica Pub Date : 2022-12-31 DOI: 10.14311/ap.2022.62.0618

J. Lechner, N. Kosarev, Igor Sergeevich Trevoho

{"title":"Conversion of units of length from the Czech state standard to the geodetic baseline Javoriv","authors":"J. Lechner, N. Kosarev, Igor Sergeevich Trevoho","doi":"10.14311/ap.2022.62.0618","DOIUrl":"https://doi.org/10.14311/ap.2022.62.0618","url":null,"abstract":"Modern society cannot do without high quality geospatial data. This need constantly strengthens with the growth of the information society and the emerging cyber society. Validity and quality of geospatial data is strongly connected to the level of its metrological service. It is necessary to conduct National metrological comparisons, in order to maintain an effective measuring infrastructure both inside a single country and in the whole Europe. The main result of such a comparison is a validation of actual values of key parameters of state standards.The article presents results of a conversion of unit of length of the state standard of the Czech Republic to the geodetic baseline Javoriv (Ukraine), as performed by the staff of the Research Institute of Geodesy, Topography and Cartography (RIGTC). The conversion was realised in cooperation with Lviv Polytechnic National University (Ukraine). High-precision measuring equipment used during the conversion includes: the Leica AT401 laser tracker and the Leica Nova MS50 electronic total station.A comparison of the measured length sections of the geodetic baseline Javoriv, performed by VUGTK employees, with the measurement results performed on a geodetic baseline Javoriv by specialists of the National Science Center (NSC) Institute of Metrology, gave a very good consistency. This is a sign of high quality results of comparative international measurement. It is planned to continue with the common efforts in the field of comparative international measurements between the Czech Republic and Ukraine in order to determine the actual values of the length sections of the geodetic baseline Javoriv.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49503240","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

IF 0.8

Acta Polytechnica Pub Date : 2022-12-31 DOI: 10.14311/ap.2022.62.0654

Linda Veselá

{"title":"Recommended procedure for headroom design according to geometric parameters of building structures","authors":"Linda Veselá","doi":"10.14311/ap.2022.62.0654","DOIUrl":"https://doi.org/10.14311/ap.2022.62.0654","url":null,"abstract":"The system of Czech technical standards for geometric accuracy assumes that the designer determines the functional geometric parameters for a specific building. By calculation, he verifies them in the so-called “geometric plan” in the project documentation. The functional geometric parameters should be determined primarily for critical elements, i.e. for structures whose geometric accuracy is important for the execution of subsequent works, such as technologies requiring high precision and specific structures. The assumption is that designers will incorporate variations in geometric accuracy primarily in the development of the spatial parameters of the structures, which should ensure that the dimensional requirements for the completed structures will be met. One of these parameters is headroom. The design of headroom must respect the minimum height requirements prescribed by legislation, and where appropriate, by technical standards. At the same time, the design must respect the technological possibilities of the construction of individual structures – geometric deviations. To comply with the dimensional requirements for the completed structures, the geometric accuracy deviations should be determined in accordance with the requirements of the technical standards for the execution of the individual parts of the building structures and/or for their design. The aim of this article is to establish a calculation procedure for determining the safe design clearance so that the requirements of the legislation are met after implementation. The increase is determined based on a calculation procedure of the limiting geometric deviations that may affect the resulting headroom.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42764969","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 Novel Study of Dielectric Properties of Discs Fabricated from Nanopowder of Calcined Clams, Periwinkle, and Oyster Shells 煅烧蛤壳、长春花壳和牡蛎壳纳米粉末制备圆盘介电性能的新研究

IF 0.8

Acta Polytechnica Pub Date : 2022-12-01 DOI: 10.1007/s41050-022-00039-z

S. Etuk, Adebayo Olusakin Adeniran, U. Robert, A. Akankpo, O. Agbasi

引用次数: 0

Oil Supply Chain Integrated Planning based on Holonic Agents and Constraint Programming 基于完整代理和约束规划的石油供应链集成规划

IF 0.8

Acta Polytechnica Pub Date : 2022-11-01 DOI: 10.1007/s41050-022-00038-0

F. Marcellino, Jaime Simão Sichman

引用次数: 0

Experimental study of the torsional effect for yarn break load test of polymeric multifilaments 高分子多长丝断裂载荷试验扭转效应的实验研究

IF 0.8

Acta Polytechnica Pub Date : 2022-10-31 DOI: 10.14311/ap.2022.62.0538

Daniel Magalhães da Cruz, F. Clain, C. E. M. Guilherme

{"title":"Experimental study of the torsional effect for yarn break load test of polymeric multifilaments","authors":"Daniel Magalhães da Cruz, F. Clain, C. E. M. Guilherme","doi":"10.14311/ap.2022.62.0538","DOIUrl":"https://doi.org/10.14311/ap.2022.62.0538","url":null,"abstract":"Polymeric multifilaments have gained a significant interest in recent decades. In the studies of mechanical characteristics, although there are different types of tests, such as rupture, abrasion, creep, impact and fatigue, it can be said that the main mechanical characterisation is the tensile rupture strength (Yarn Break Load, YBL), which also serves as a parameter for other tests. The objective of this work is to evaluate the results of breaking strength under different torsional conditions in polymeric multifilaments and to determine optimal twists for failures. The test were carried out with the following materials: polyamide, polyester, and high modulus polyethylene (HMPE), and for torsional conditions: 0, 20, 40, 60, 120, 240, and 480 turns per metre. As a result, for these torsion groups, curves were obtained for the three materials that present an optimal point of maximum rupture value, which was also experimentally proven. The twist that optimises the breaking strength of HMPE is 38 turns per metre, 56 turns per metre for polyester, and 95 turns per metre for polyamide. The twist groups that exceed the optimal torsion have a deleterious effect on the material, where the multifilament ceases to be homogeneous and starts to create an excessive \"spring effect\". The results found differ from the recommendation of the standard that regulates the YBL test, and thus, a relationship is built between groups of optimal torsion and linear density that provides evidence that the increase in linear density causes the optimal torsion for rupture to also increase, while the standard places a condition of 30 turns per metre for linear densities greater than 2200 dtex, and 60 turns per metre for linear densities less than 2200 dtex. In addition to optimal torsion values, this conclusion is paramount, the test procedure makes a general recommendation that does not optimise the breaking strength.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41509711","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: 1

The engineering performance of eco-friendly concretes containing diatomite fly ash and ground granulated blast furnace slag 硅藻土粉煤灰与磨粒矿渣环保型混凝土的工程性能

IF 0.8

Acta Polytechnica Pub Date : 2022-10-31 DOI: 10.14311/ap.2022.62.0505

H. Y. Aruntas, Erkan Yıldız, G. Kaplan

{"title":"The engineering performance of eco-friendly concretes containing diatomite fly ash and ground granulated blast furnace slag","authors":"H. Y. Aruntas, Erkan Yıldız, G. Kaplan","doi":"10.14311/ap.2022.62.0505","DOIUrl":"https://doi.org/10.14311/ap.2022.62.0505","url":null,"abstract":"Approximately 10 % of CO2 is emitted from an ordinary Portland cement production. In cement and concrete production, CO2 emissions can be greatly reduced by using Supplementary Cementitious Materials (SCMs). In addition, the microstructure and durability properties of concrete are greatly improved when silica-rich SCMs are used. In this study, Eco-Friendly concrete design was carried out using three different SCMs. Diatomite, ground granulated blast furnace (GGBFS) and fly ash (FA) were used as the SCM in the concrete mixtures. SCMs were used instead of cement at ratios of 5, 10, 15, and 20 wt %. When diatomite was used at the rate of 20 %, the standard consistency water increased 1.7 times as compared to the reference mixture. With the increase in the replacement ratio, the final setting times of the pastes increased. The high active SiO2 content of diatomite shortened the initial setting time and increased the compressive strength. The use of 5 % diatomite reduced the slump value by 57 % as compared to the reference mixture. The slump and Ve-Be tests of GGBFS and FA mixtures showed similar properties to the reference mixture. The 28-day compressive strength of concrete varied between 29.2–34.6 MPa. With the increase in the curing time of the concrete mixtures, up to 50 % improvements were observed in the compressive strength. Especially on the 180th day, a compressive strength of 44.1 MPa was obtained in concrete mixtures with a 10 % replacement ratio. While using the FA in the mixtures improved the abrasion properties, the opposite result was observed in the case of the GGBFS. It was observed that the mixtures with 5 % FA showed the closest properties to the reference mixture. As a result, it was determined that SCMs with different properties could be used in environmentally friendly concrete mixtures by up to a 20 % replacement ratio.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48118348","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: 1

Low earth orbit nanosatellite: influence of heat dissipation on passive thermal analysis 近地轨道纳米卫星:散热对被动热分析的影响

IF 0.8

Acta Polytechnica Pub Date : 2022-10-31 DOI: 10.14311/ap.2022.62.0498

A. Akka, F. Benabdelouahab, R. Yerrou

引用次数: 0

Determination of fan design parameters for light-sport aircraft 轻型运动飞机风扇设计参数的确定

IF 0.8

Acta Polytechnica Pub Date : 2022-10-31 DOI: 10.14311/ap.2022.62.0549

J. Klesa

引用次数: 0