Applied sciences

Archives of Civil Engineering

Content

Archives of Civil Engineering | 2022 | vol. 68 | No 4

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Abstract

The hyperloop concept is not new, but for many years it was hard for engineers to believe that it could be economically and technically feasible. Nowadays some technical solutions, which could enable construction and operation of a guided transport system based on hyperloop concept, are much more imaginable. Therefore a number of start-up companies are working on comprehensive proposals and chosen technologies aiming at creating the fifth transport mode thanks to innovative concepts, new technologies, and chosen railway, air transport, and space technologies. As new transport mode is expected to offer transport with high speed nearly equal to the speed of sound its feasibility will strongly depend also on coherency between transport means and transport infrastructure in a scale of a future fifth transport mode continent-wide transport network. To meet this challenge railway and start-up companies work together in two streams – in the formal framework of the European standardisation to prepare future hyperloop related EN standards and in research and development projects. The scale of required wide technical coherency on one side and the diversification of products and existence of different developers/producers/contracting entities providing infrastructure and transport means and creating market on the other side contradict if appropriate rules are not set precisely early enough. Such rules in railway transport are based on interoperability concept supported by agreed stable essential requirements and defined in the Railway Interoperability Directive and Technical Specifications for Interoperability. Paper presents findings regarding poor applicability of the railway interoperability to the hyperloop type transport systems at their early stage of development as well as challenges and proposed approaches for the dedicated hyperloop coherency approach – the hyperoperability as it is being discussed in the framework of the Hypernex European project.
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Authors and Affiliations

Agnieszka Kaczorek
1
ORCID: ORCID
Iwona Karasiewicz
1
ORCID: ORCID
Magdalena Kycko
1
ORCID: ORCID
Marek Pawlik
1
ORCID: ORCID
Krzysztof Polak
1
ORCID: ORCID
Wojciech Rzepka
1
ORCID: ORCID

  1. Railway Research Institute, Chłopickiego 50, 04-275 Warsaw, Poland
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Abstract

Worker absenteeism is identified as the greatest threat to not meeting the completion date of a construction project. The purpose of this paper is to quantify the impact of employee absenteeism risk on the probabilistic lead time of a construction project. Calculations of employee absenteeism risk values were performed using data from the Central Statistical Office (Big Data). Probabilistic schedules with probability density functions (Normal, Exponential, Reyleigh, Triangle, Gamma, Cauchy) with and without calculated employee absenteeism risk were prepared. Student’s t-test and MAPE analysis of mean absolute percentage errors were performed to determine differences between groups. It was found that with respect to the probability of completing the task in the range of 75 to 95% for all functions, an unacceptable MAPE error of 32.82% to 69.23% arises. Therefore, the authors postulate that the risk of worker absenteeism should be considered in every construction process when performing probabilistic scheduling, i.e., in the Building Information Modeling BIM methodology.
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Authors and Affiliations

Magdalena Rogalska
1
ORCID: ORCID
Zdzisław Hejducki
2
ORCID: ORCID

  1. Lublin University of Technology, Faculty of Civil Engineering and Architecture, ul. Nadbystrzycka 40, 20-618 Lublin, Poland
  2. Wrocław University of Science and Technology, Faculty of Civil Engineering, Plac Grunwaldzki 11, 50-384 Wrocław, Poland
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Abstract

In this study, direct shear tests were carried out on cement mortar specimens with singleladder, single-rectangular, and double-rectangular step joints. Consequently, the shear strength, and crack shape of specimens with these through-step joints were analyzed, for understanding the influence of the through-step joint’s shape on the direct shear mechanical properties. The results of the investigation are as follows: (1) Under the same normal stress, any increases in the height ℎ of the step joint causes an initial-increase-decrease in the shear strengths of specimens with single-ladder and double-rectangular step joints, causing a type-Wvariation pattern for the specimens with single-rectangular step joint. More essentially, when normal stress and ℎ are constant, the shear strength of specimens with a single-ladder step joint is the greatest, followed by specimens with a double-rectangular step joint, and then specimens with a single-rectangular step joint is the least. (2) Furthermore, given a smallℎ and low normal stress, specimen with a single-ladder step joint mainly experiences shear failure, whereas specimens with single-rectangular and double-rectangular step joints mainly generate extrusion milling in the step joints.
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Authors and Affiliations

Liangxiao Xiong
1
ORCID: ORCID
Haijun Chen
2
ORCID: ORCID
Haogang Guo
3
ORCID: ORCID
Songhua Mei
1
ORCID: ORCID
Zhongyuan Xu
4
ORCID: ORCID
Bin Liu
5
ORCID: ORCID

  1. Hunan Provincial Key Laboratory of Hydropower Development Key Technology, Power China Zhongnan Engineering Corporation Limited, Changsha 410014, China
  2. Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
  3. Civil and Environmental Engineering Department, Carnegie Mellon University, Pittsburgh 15289, United States
  4. Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
  5. School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China
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Abstract

The technology of single bore multiple anchor is well known and mainly used as a method of providing support for retaining walls of deep excavations in weak soils. Multiple fixed lengths in a single borehole is a major difference to conventional anchors. The purpose of it and the most important facts affecting bearing capacity are presented. Due to the reduction of progressive debonding higher bearing capacities can be achieved and the impact of soil consolidation is decreased. Unique properties of this technology potentially reduce construction costs and increase the reliability and safety of the structure. Single Bore Multiple Anchors in most cases are prestressed by synchronised hydraulic jacks to provide that every anchor unit transfers the same load. The purpose of this paper is to present the results of investigation and suitability tests, which took place at the site of Zlote Tarasy Shopping Centre in Warsaw. The carried out research reveals that prestressing of one fixed anchor causes a decrease in lock-off load of the second fixed anchor, regardless of the order of prestressing. Measured values presents range from 6% to 14%. Results indicate mutual influence between loads of fixed anchors from the separate prestressing.
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Authors and Affiliations

Jan Kalicki
1
ORCID: ORCID
Monika Mitew-Czajewska
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 0-637 Warsaw, Poland
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Abstract

This paper outlines effect of the mix composition on mechanical properties of high–strength concrete based on aggregate size like in of Reactive Powder Concrete (RPC) but without fiber reinforcement. The main purpose which guided the authors choosing proportion of water and superplasticizer (SP) was to achieve a similar consistency in the test slump for various concrete mix. Test results for 3 groups of superplasticizers, designated as D – with chemical base – acrylic polymer, V – with chemical base – polycarboxylate ether, P – with chemical base – modified polycarboxylates, two cement groups, designated as Cem A – with fineness Blaine 3980 cm 2/g, Cem B – with fineness Blaine 4430 cm 2/g and 2 types of aggregate: basalt and granite were presented. After curing for 1, 7 and 28 days samples were tested for compressive strength and flexural tensile strength. The article also presents the study of the elemental composition and structure of the SP with the use of the SEM electron microscope. The amount of solid particles in the SP was also determined by the water vaporization. The assumption of the paper was to maintain the consistency of the mixture at the S2 level according to the Eurocode standard. The paper proposes a method based on SEM analysis in order to select a superplasticizer with the best ductility parameters, and the best results of the compressive and flexural tensile strength of concrete samples were obtained. The best results for compressive strength after 28 days are obtained for concrete series with the polycarboxylate ether superplasticizer and modified polycarboxylate ether superplasticizer in combination with the use of type A cement and it is greater than for the concrete series with type B cement by 11.7%.
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Authors and Affiliations

Jarosław Siwiński
1
ORCID: ORCID
Anna Szcześniak
1
ORCID: ORCID
Barbara Nasiłowska
2
ORCID: ORCID
Zygmunt Mierczyk
2
ORCID: ORCID
Katarzyna Kubiak
3
ORCID: ORCID
Adam Stolarski
1
ORCID: ORCID

  1. Military University of Technology, Faculty of Civil Engineering and Geodesy, 2 gen. S. Kaliskiego Street, 00-908 Warsaw, Poland
  2. Military University of Technol