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Number of results: 41
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Abstract

The by-products of wood sawdust and wood fiber are considered to be waste material. It is utilized in the construction of buildings in the form of sawdust concrete or wood fiber concrete. It is used to make lightweight concrete and possesses heat transfer of a long duration. In this study, wood concrete was made at eleven different mix proportions of cement to wood waste by weight, to produce a lightweight concrete aggregate that has the density 1508-2122 kg/m3. The experimental work consists of 330 concrete specimens as 99 cubes (150 * 150 * 150) mm, 165 cylinders (150 * 300) mm, 33 prisms (50 * 100 * 200) mm, and 33 prisms (100 * 100 * 500) mm. Mechanical and thermal properties such as stiffness, workability, compressive strength, static elasticity modulus, flexural forces, splitting tensile strength and density were examined in the specimens after 28 days of 20 oC curing. Also, compressive strength was investigated at 7 and 14 days of curing at 20 oC. The basic observation of the results shows the values with the limitations of ACI and ASTM. Moreover, it is the perfect way to reduce solid wood waste and produce lightweight concrete to be used in industrial construction. It was found that with the increase in the quantity of wood waste, the strength decreased; however, in terms of workability and concrete with a higher quantity of wood waste held very well. Lightweight concrete aggregate is around 25 percent lighter in dead load than standard concrete. Given all the physical and mechanical properties, the study finds that wood concrete can be used in the construction of buildings.

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Authors and Affiliations

Salam Salman Chiad Alharishawi
ORCID: ORCID
Haitham Jameel Abd
Suha Rasheed Abass
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Abstract

Due to demand of tightness, the liquid tanks should be designed with particular care. In addition to the liquid pressure, the imposed concrete strains and thermal actions should be taken into consideration. Furthermore, the verification of the ULS in persistent design situation only is not sufficient. The crack control both in persistent situation as well as in early age transient one is necessary for determination of the reinforcement. In the beginning of the design process some assumptions, influencing the future tank performance must be made. First, the tightness class must be chosen, followed by formulation of conditions for crack width control. Next, the critical age of concrete, proper for early age transient situation should be assumed. This age determines the value of imposed strain on the one hand and the effective tensile concrete strength on the other. Then, it should be decided, if any reduction of the effective tensile strength would be applied (reduction associated with nonuniform imposed strain and reduction due to cracking under other combination of actions). Eventually, the decisions for structural analysis should be made, concerning the values of combination factors for actions both for ultimate and cracking limit state and the possible reduction of cross-section stiffness due to cracking caused by thermal actions in ULS.

The above-mentioned assumptions are listed and discussed in the paper. On the basis of the discussion the algorithm for crack control in concrete tanks is worked out and proposed. The issues are illustrated with practical example of cylindrical tank for liquid.

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Authors and Affiliations

Anna Halicka
ORCID: ORCID
Dominika Franczak-Balmas
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Abstract

The purpose of this paper is to investigate the effects of natural uncertainties and effective parameters on the stability of plate-type rock walls. For this, the effective factors and geo-mechanical properties in the study area were obtained using field experiments. Stability analysis of rock walls was investigated for 40 scenarios in dry and saturated states. These parameters were then evaluated using Easyfit software and Markov chain analysis and Monte Carlo simulation by Rock Plane software. Comparison of the results of numerical and uncertainty methods shows that the rock walls with 60-80 degree slope are stable; and In saturated state they require stability due to the reduction of shear strength. Fixation of the rock walls was also investigated, indicating an optimum angle of 30° for the installation of the rock screw. The results show that the Monte Carlo simulation provides a simpler interpretation and the uncertainty methods are more accurate and reliable than the numerical methods.

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Authors and Affiliations

Sina Mokhtar
Mostafa Yousefira
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Abstract

The aim of this paper is a comparative analysis of the experimental test results of twenty T-section beams reinforced with glass fiber reinforced polymer (GFRP) bars without stirrups with predicted values of the shear capacity according to the following design guidelines: draft Eurocode 2, Japanese JSCE, American ACI 440, Italian CNR- DT-203/2006, British BS according to fib Bulletin 40, Canadian CSA-S806-12 and ISIS-M03-07. Standard procedures for FRP reinforced beams based on traditional steel reinforced concrete guidelines. The longitudinal FRP reinforcement has been taken into account by its stiffness reduction related to the steel reinforcement. A basis of this modification is the assumption that the FRP-to-concrete bond behaviour is the same as it is for steel reinforcement. To assess the compatibility of predicted values (Vcal) with the experimental shear forces (Vtest) the safety coefficient η = Vtest / Vcal was used. The results corresponding to values η < 1 indicates overestimation of the shear capacity, but η > 1 means that shear load capacity is underestimated. The most conservative results of the calculated shear capacity are obtained from the ACI 440 standard. In contrast to them the best compatibility of the calculated shear values to the experimental ones indicated British BS standard, fib Bulletin 40 and Canadian CSA-S806-12 standard.

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Authors and Affiliations

Monika Kaszubska
ORCID: ORCID
Renata Kotynia
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Abstract

The diagnostics of track superstructure, which involves geometric measurements, direct observation and railroad surveillance, provides the basis for making decisions regarding the commencement of repair works. Planning repairs and increasing the probability of making the right decision at the right time also requires knowledge of the basic performance specifications of a given railway line, especially the maximum train speed and the permissible traffic volume. The article discusses a way to plan the repairs of track superstructure using artificial neural networks. It features a description of the process of designing, building and training a neural network, based on which a way to predict the degree of urgency of repairs has been discussed. The conclusions point towards the potential advantages of neurocomputers in the process of track superstructure maintenance.

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Authors and Affiliations

Henryk Bałuch
Iwona Nowosińska
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Abstract

Arch bridges are built since two thousand years at least. Structural materials changed during this time. The design methods were changed also. The biggest impact was noted with development of Finite Element Method and graphical methods of preparation of technical drawings which is strictly combined with development of computers. These processes appeared also in Polish construction industry, especially from the beginning of 90-ties XX century.

But in this paper we do not consider mentioned above problems. We would like to present development of arch bridges from construction technology point of view. This aspect of creation of bridge structures is not very often the subject-matter of analysis. For many investors, design engineers and contractors optimization of structures is most important issue. For most of them the reduction of volume (weight) of structural material is only solution. But sometimes it is not true – the construction technology gives much more efficient results.

We present below examples of realization in Poland medium and large span arch bridges – steel, concrete and hybrid structures.

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Authors and Affiliations

Tomasz Siwowski
ORCID: ORCID
Henryk Zobel
ORCID: ORCID
Thakaa Al-Khafaji
ORCID: ORCID
Wojciech Karwowski
ORCID: ORCID
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Abstract

A theoretical approach was applied to investigate the impact of nonlinear standing waves underneath a horizontal deck. A solution was achieved by applying a boundary element method. The model was applied to predict impact pressure underneath a deck. The results show that the wave impact is a very complex momentary process. The influence of initial boundary conditions, wave parameters and deck clearance on impact pressure are analysed. The analysis shows that purely sinusoidal waves of very small amplitude may cause an impact pressure several orders of magnitude higher than a pressure arising from typical applications of a linear wave theory. The analysis shows that all these non-intuitive outcomes arise from the complexity of a wave impact process and its enormous sensitivity to initial conditions what indicates serious difficulties in a reliable prediction of a wave impact for complex wave fields or other structures. Laboratory experiments were conducted to validate theoretical results.

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Authors and Affiliations

Dawid Majewski
Wojciech Sulisz
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Abstract

This paper includes the behaviour of RC column, using the steel strength data employed by Rafi et al. (2014). Eccentric short columns are studied for this purpose, both tension and compression controlled sections, are analysed considering the current design practice of Pakistan. Three cross sections were analysed using different steel percentages against load-moment interaction and the strength analyses. Concrete strength is also varied in this analysis. The load moment interaction diagrams were observed in major and minor axes and strength analysis is made for compression controlled and tension controlled sections. In this analysis it is observed that a section designed as a tension controlled is giving brittle failure at certain limit which should be avoided. Considering this scenario, several random cross sections are analysed, strength reduction factors for eccentric and pure axial columns are computed. Conclusions are made on behalf of this analysis for different types of column design.

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Authors and Affiliations

Safdar Abbas Zaidi
Muhammad Arsalan Saeed
Farhan Haider
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Abstract

The manuscript presents the research results concerning the properties of concrete with non-clinker, low-emission binder composed of by-products from metallurgy and power industry: ground granulated blast furnace slag and fly ash from circular fluidized-bed combustion of brown coal. The binder was added in five proportions. The consistency and air content of the concrete mix were measured, as well as the temperature of the concrete mix during hardening. The compressive strength of the hardened concrete was investigated in three periods of samples’ curing: after 28, 90 and 360 days. Also the penetration depth of water under pressure and freeze and thaw resistance of concrete samples were investigated. The results confirm the possibility of application of slag-CFBC fly ash binder for mass concrete due to low temperature during hardening. The obtained results of the compressive strength and penetration depth of water under pressure reveal the influence of changing the proportion of the binder ingredients, as well as the sample damage during testing the freeze/thaw resistance. The CFBC fly ash-slag binder can be used for mass concrete, hydrotechnical concretes in particular, but excluding the zones exposed to frost.

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Authors and Affiliations

Agnieszka Machowska
ORCID: ORCID
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Abstract

The paper presents development of the new Polish method for performing capacity analysis of basic segments of dual carriageway roads (motorways and expressways). The method is based on field traffic surveys conducted at 30 motorway and expressway sites (class A and S roads) in Poland. Traffic flows, composition and travel times were observed in 15-min intervals at each site using ANPR filming method. These data were used to calibrate a family of traffic speed-flow relationships for different roads, based on Van Aerde model. Free flow speed of traffic and road class are the basic parameters defining the speed-flow relationship and the value of capacity per lane in pcu/h. Traffic density was adopted as the measure of effectiveness for defining the level of service. The paper describes derivation of formulae for estimation of free flow speed for different types of roads as well as determination of equivalent factors for converting vehicles to passenger car units. The method allows us to determine capacity and the level of service based on existing or forecasted traffic flow.

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Authors and Affiliations

Piotr Olszewski
ORCID: ORCID
Tomasz Dybicz
Wojciech Kustra
ORCID: ORCID
Aleksandra Romanowska
Kazimierz Jamroz
ORCID: ORCID
Krzysztof Ostrowski
ORCID: ORCID
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Abstract

The article presents the results of experimental research aimed at recognizing the impact of the design of energy dissipation devices on the formation of bed local scouring below the sluice gate. The experiments were carried out on a model of a sluice gate built in a rectangular flume with a width of 0.58 m, with the outflow of the stream from under the slider to a horizontal bed 0.80 m long. Behind the dam gate valve three different constructions of energy dissipation devices were used: flat, horizontal slab, slab equipped with baffle blocks arranged in two rows and rip-rap. The experiments assumed forming a scour hole in 480 minutes downstream the sluice, where the bed was filled with sorted sand. The depths of the scour were measured in the longitudinal profile after 30, 60, 90, 120, 180, 240, 300, 360, 420 and 480 minutes. The deepest scour holes of the bed, both in terms of depth and length, occurred on the structure model with energy dissipation devices made as a flat, horizontal plate. At the same time, in this case, the hole was developing the most rapidly, and its shape and size posed the greatest threat to the stability of the structure. The use of baffle blocks arranged in two rows or a rip-rap behind the structure slide noticeably reduced the size of the scour and delayed the erosion of the bottom in time, as compared to the course of this process on a model with a flat, horizontal slab.

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Authors and Affiliations

Janusz Urbański
ORCID: ORCID
Marta Justyna Kiraga
Sławomir Bajkowski
ORCID: ORCID
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Abstract

The paper focuses on the development of knowledge about the hot bending of curved architectural glass produced by the slumping process and the challenges as well as the limitations thereof. Due to the complexity of the process, many factors influence the final quality of the glass and the main objective was to better understand the procedure itself in order to improve the control and quality of the slumping process. As a result of the growing interest in this type of glass for architectural applications, the glass processing market is increasingly investing in the required technology. For the moment, this growing niche does not have a large number of direct explanations of the glass behaviour in the furnace in the available literature, which in turn encourages cooperation between the scientific community and manufacturers. This paper presents the conducted experiments that have led to a better understanding of the furnace's work and the impact of specific factors on its operation. Based on the 3D numerical model, a large sample of glass was produced, which was then scanned with a 3D laser using a method developed for the experiment. The results suggested that a more accurate test with usage of a full-size furnace is required. Based on this, the experiment was carried out using a large number of glass samples of different thicknesses. The results of the experiment helped to better understand and demonstrate the need for further research of this technology in order to optimize the quality of the process.

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Authors and Affiliations

Andrzej Malewski
Marcin Kozłowski
Wojciech Sumelka
Marek Połedniok
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Abstract

The setback is a frequent type of irregularity expected in complex-shaped buildings. The main purpose of the present paper is to emphasize the influence of setback location on the performance of reinforced concrete building structures under seismic excitation. In this research study, 68 building models with setback values vary from 0.1L to 0.5L, located at various levels, are studied. Non-linear static (pushover) analyses were conducted. All building models are analyzed using a finite element calculation code. The outcomes show that setback irregularity location has a significant effect on the seismic behavior of the structure. Based on the regression analysis of the results obtained in the current study, a mathematical formula is proposed to quantify the effect of setback location on the performance of building structures. The results of this study would aid all professionals in the building sector to anticipate the response of these types of structures during the design phase.

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Authors and Affiliations

Mohamed Mouhine
Elmokhtar Hilali
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Abstract

The physical and chemical properties of cements with slag originated from the storage yards of different age, added as a supplementary cementing material are highlighted. The materials after 20-year storage, the crushed slag after approximately 2-year storage and the new slag from the ongoing production were compared. The materials supplied by the same metallurgical plant were characterized. The blended cements were produced by Portland cement clinker grinding with gypsum and slags added as 5 to 50% of binder mass. The standard properties of cements were examined, as well as some experiments related to the kinetics of hydration and hydration products were carried out. The addition of granulated blast furnace slag (GBFS) stored for a long time, as a component of cement, affects the properties of material in such a way that the early compressive strength is not specially altered but at longer maturing the strength decreases generally with the storage time and percentage of additive. This is related to the reduction of the vitreous component, as well as to the presence of weathered material of altered activity. At the additive content up to 50% the binder complying with the requirements of the European standards for CEM III/A or CEM II/(A,B)-S common cements can be produced. The cements with the old slag meet the requirements of EN 197-1 relating at least to the class 32,5. The role of calcium carbonate, being the product resulting from the slag weathering process, acting as a grindability and setting/hardening modifying agent, should be underlined.

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Authors and Affiliations

Wiktor Pacierpnik
Wiesława Nocuń-Wczelik
Ewa Kapeluszna
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Abstract

The use of old building design codes and improper execution of recent seismic design practices have caused large amount of substandard and vulnerable reinforced concrete RC building stock majority of which are built with weak beam-column joint connections defect (i.e. joint panel having no transverse reinforcement and built in low strength concrete). In order to understand the seismic response and damage behaviour of recent special moment resisting frame SMRF structures with the defect of weak beam-column joints, shake table tests have been performed on two 1:3 reduced scaled, two story RC frame models. The representative reference code design and weak beam-column joint frame models were subjected to uni-directional dynamic excitations of increasing intensities using the natural record of 1994 Northridge Earthquake. The input scaled excitations were applied from 5% to 130% of the maximum input peak ground acceleration record, to deformed the test models from elastic to inelastic stage and then to fully plastic incipient collapse stage. The weak beam-column frame experienced column flexure cracking, longitudinal bar-slip in beam members and observed with cover concrete spalling and severe damageability of the joint panels upon subjected to multiple dynamic excitations. The deficient frame was only able to resist 40% of the maximum acceleration input as compared to the code design frame which was able to resist about 130%. The seismic performance of considered RC frames was evaluated in terms of seismic response parameters (seismic response modification, overstrength and displacement ductility factors), for critical comparison.

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Authors and Affiliations

Muhammad Rizwan
Naveed Ahmad Akhtar
Naeem Khan
Muhammad Fahad
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Abstract

The research paper presents the results of hydraulic conductivity, pore structure, phase composition and microstructural tests of hardening slurries prepared using Portland cement, bentonite, water and fluidized-bed ashes coming from hard coal and lignite combustion. The slurries were subjected to long-term (210 days) exposure to the filtering action of an environment strongly aggressive to a cement binder. A sulphate solution 2- with sodium content of SO4 2- = 6700 mg/l was applied, which modelled sulphate aggression. The comparative base were samples subjected to filtration in tap water (neutral environment).

The test covered dependencies between hydraulic conductivity k10 (filtration coefficient) and the parameters characterizing porous structure in the slurry, as well as the impact of an aggressive medium on slurry tightness (its porosity and hydraulic conductivity). Changes in the phase composition and slurry microstructure were analysed in terms of its corrosion resistance to the action of sulphate aggression.

Observations from other researchers have been confirmed that the use of fluidized fly-ash addition has a positive effect on increasing the resistance of cement matrix exposed to sulphate aggressiveness.

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Authors and Affiliations

Paweł Falaciński
ORCID: ORCID
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Abstract

The problem of uniqueness and representativeness of steel frame fire resistance assessment is considered in this paper. The thesis, that the selection of analysis method determines the result in both qualitative and quantitative terms is given scrutiny. It is also shown, that the differences between computed values may be significant. The selection of an appropriate computational model for an analysis of this type seems to be especially important, as the possible overestimation of the fire resistance determined during computation is equivalent to an unjustified optimism of the user with respect to the safety level warranted. In the considerations presented here the critical temperature determined for the whole bearing structure is considered as the measure of sought resistance. The determined temperature is associated with the bearing structure reaching the bearing capacity limit state subject to fire conditions, treated as accidental design situation. Two alternative computational methods have been applied during calculations: the first one – classical, based on 1st order statics and using the buckling length concept for members of the considered frame, and the second one – taking account of 2nd order phenomena via simple amplification of the horizontal loads applied to the frame. Special attention has been paid to the influence exerted on the final fire resistance of the considered structure by the real joint rigidity, decreasing with increasing temperature of the structural members. The obtained results differ not only in the value of determined temperature but also in the indicated location of the weakest frame component, determining its safety.

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Authors and Affiliations

Mariusz Maślak
ORCID: ORCID
Michał Pazdanowski
ORCID: ORCID
Małgorzata Snela
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Abstract

The implementation of a new, high-performance float flat glass manufacturing technology in Europe, in conjunction with the growing interest in new glass functions expressed by the construction industry, has led to significant developments in the theory of glass structures. Long time research conducted in the EU countries has been concluded by the technical document CEN/TC 250 N 1060, drawn up as a part of the work of the European Committee for Standardization on the second edition of Eurocodes (EC). The recommendations pertaining to the design of glass structures have been foreseen in the second edition of the Eurocodes, in particular the development of a separate design standard containing modern procedures for static calculations and stability of glass building structures (cf. works M. Feldmann, R. Kasper, K. Langosch and other).

In this paper new static analysis methods for glass plates made of monolithic and laminated glass, declared in th document CEN/TC 250 N 1060 (2014) and recommended in the national standarization document CNR-DT 210 (National Research Council of Italy, 2013) are presented. These static analysis methods are not commonly known in our national engineering environment, and thus require popularization and regional verification. Numerical and analytical simulations presented in this paper for rectangular plates made of monolithic and laminated glass and having various support conditions are of this character. The results of numerical calculations constitute a basis for the discussion of new static analysis methods for plates.

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Authors and Affiliations

Marian Gwóźdź
ORCID: ORCID
Piotr Woźniczka
ORCID: ORCID
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Abstract

In the last decade many buildings such as multipurpose buildings, malls, auditoriums, sports halls which have long-span building floor structure. Various research results indicate that in general long-span concrete floor structures have a fundamental frequency of less than 7 Hz. This will risk a resonance if this floor receives dynamic loads of people jogging to follow the song with a frequency of 2-3 Hz. This research was conducted to numerically analyze the long-span building floor model using SAP2000, to determine the fundamental frequency and maximum displacement of the floor structure model. It was also investigated how to increase its fundamental frequency and reduce the maximum displacement. The results have shown that the numerical analysis of the plate model long-span floor building using SAP2000 produces a fundamental frequency of 5.19 Hz. Model III with Reinforcing double equal angles (84x37x10x2.5) steel truss provides the best results, increases the fundamental frequency to be 7.93 Hz, and with a variety of static and dynamic loads, decreases the value of the displacement and far from the allowable displacement.

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Authors and Affiliations

Bambang Supriyadi
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Abstract

To promote the application of aeolian sand resources for steel-concrete composite structures, an aeolian sand reinforced concrete column with I-shaped structural steel is proposed in this study. Four specimens are designed and manufactured with different replacement rates of aeolian sand. The seismic behaviour and damage evolution process of the specimens are studied by low-cycle repeated loading tests. Based on the test results, the mechanical characteristics, failure modes, hysteresis curves, skeleton curves, energy dissipation capacity, displacement ductility, and stiffness degradation of the specimens with different replacement rates of aeolian sand are analysed. In addition, the effects of the design parameters on the seismic behaviour of the specimens are also studied. The results show that the indexes of the seismic behaviour can be significantly improved by adding steel. Moreover, a revised damage model is proposed, to better reflect the evolution law of seismic damage of aeolian sand reinforced concrete columns with steel. The proposed model can provide an important reference for seismic damage assessment of the columns.

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Authors and Affiliations

Yaohong Wang
Heyan Wang
Yanpeng Wang
Meng Zhao
Jin Qi
Guangzong Huo
Peiqi Liu
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Abstract

The paper presents the results of research concerning the assessment of dynamic resistance of existing industrial hall structures located in areas with different seismic activity. The basis for analyses was a three-nave industrial hall with a steel structure. Numerical calculations were performed using the finite element method (FEM), using the response spectrum method in dynamic analysis. The calculations were carried out in variants, using standard accelerated response spectra according to Eurocode 8 and those determined for the Upper Silesian Coal Basin (USCB) and Legnica-Glogow Copper District (LGCD) area. Using the author's procedure for the assessment of the dynamic resistance, for each of the extortion analysed, the structure's response to the dynamic excitation was compared with the effects of load combinations adopted at the design stage, thus establishing the limit values of the design horizontal ground acceleration a max/g,h understood as the structure's resistance to tremors. This allowed to assess the impact of seismic activity from a specific area on the dynamic resistance of the subjected object. The article also discusses the way of interpretation and the scope of application of the obtained results and proposed procedure.

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Authors and Affiliations

Janusz Rusek
ORCID: ORCID
Leszek Słowik
ORCID: ORCID
Karol Firek
Michał Pitas
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Abstract

Ballast layer has weighty share in the lifecycle costs of railway track. The strict standards and maintenance rules of ballast grading significantly contribute to the ballast costs. One ways to the costs reduction is differential demands to ballast grading for the secondary and low loaded railway lines. Additional one is the different ballast grading over the ballast height. This study presents a full scale laboratory investigation of technical efficiency of such railway ballast under the long-term cyclic loading in comparison with the standard ballast layer. The double layer is presented with standard grading ballast upper layer and bottom sub ballast layer consists of ballast mixture. Pressure distribution under the ballast layer and permanent settlements of the layers are measured during the loading cycles. The reference measurements with standard grading ballast material are carried out. The study shows that initial settlement accumulation of the double layer railway ballast are lower to that of the standard ballast layer. However, the settlements accumulation intensity of the ballast is higher. The analysis of the pressure distribution measurements under the ballast layer and the settlements inside the ballast layer explain the causes of the different settlement accumulation.

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Authors and Affiliations

Mykola Sysyn
Ulf Gerber
Olga Nabochenko
Stefan Dehne
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Abstract

International scales describing the intensity of tornadoes are investigated along with reports from the Polish Government Security Centre on all types of wind storms in Poland. Then, collected tornado reports for the years 1899–2019 in Poland, a set of the annual maximum gust wind speeds measured at 39 meteorological stations from 1971 to 2005 (35 years), descriptions of Poland’s strongest wind storms in the 21st century, estimating the risk of significant strong and extreme winds in Poland, and classification of maximum wind speeds by Lorenc (2012) are presented. Based on these data, i.e. measured and estimated wind speeds, this paper proposes two separate intensity scales to categorize synoptic, thunderstorm, and downslope winds (in the Tatra and Karkonosze regions), derechos, tornadoes, and downbursts, i.e. all types of wind storms. These scales are simpler than the one put forward by Lorenc (2012). These two scales cover a range of maximum wind speeds from 20 to 90 m/s. This proposal is only applicable to Poland. Other countries may determine whether it applies to them.

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Authors and Affiliations

Tadeusz Chmielewski
Henryk Nowak

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