75504 2712-8172 Magazine of Civil Engineering 8 108 2021 1-197
RAR RUS 10801-10801 0000-0002-6045-9353 Central South University Liu Shouhua 18945087415@163.com
Changsha City, Hunan Province, China
 0000-0002-5905-5175 Cccc Second Harbour Eingineering Company Design & Research Institute Co. Shi Yao 734169065@qq.com
Wuhan, China
 0000-0002-2440-9754 Central South University Zhao Yiding zhaoyiding89@126.com
Changsha City, Hunan Province, China
 0000-0001-7691-2995 Central South University Sun Rui 3617384841@qq.com
Changsha City, Hunan Province, China
 Interaction and control measures of shallow-buried shield twin tunnels with small clear-distance When constructing small clear-distance tunnels in complex geotechnical conditions, there are many challenges including intolerable ground movement, face failure, and potential damage to adjacent tunnel. This paper focused on the study of small clear-distance shield tunnel construction in the typical upper-soft and lower-hard stratum. Numerical analyses are conducted to estimate the influence of the new tunneling on the existing tunnel. In addition, partition wall accompanied by cement-soil mixing pile is adopted as the control measure. The results demonstrate that the construction of the new tunnel has a big impact on the stability of the existing tunnel. The seal roof block should not be placed on the top region. The obviously influenced region of the existing tunnel agrees with the excavation diameter of the new tunnel, so monitoring in this region should be strengthened. Moreover, the safety control effect has been verified by numerical analysis and field test. This study provides a basis for the design and construction of tunnels with shallow buried depths and small clear-distances. 10.34910/MCE.108.1 earth pressure balance (EPB) shield twin tunnels tunnelling interaction finite element method ABAQUS testing https://engstroy.spbstu.ru/article/2021.108.1/
RAR RUS 10802-10802 Department of Civil Engineering, Qazvin Branch, Islamic Azad University Jamalpour Najmabad Saeid saeidjamalpournajmabad@gmail.com
Qazvin, Iran
 Department of Civil Engineering, Qazvin Branch, Islamic Azad University Seyed Razzaghi Mehran razzaghi.m@gmail.com
Qazvin, Iran
 Structural Engineering Research center, International Institute of Earthquake Engineering and Seismology(IIEES) Nateghi Alahi Fariborz nateghi@iiees.ac.ir
Tehran, Iran
 Application of SMA anchors to the seismic performance of tanks This paper is aimed at investigating the feasibility of using shape memory alloy (SMA) materials as anchor bolts in steel liquid storage tanks. The seismic performance of a case study liquid storage tank anchored with steel and SMA bolts is evaluated. For this purpose, a parametric study is performed to determine the optimum length and diameter of the anchor bolts which results in the minimum tank uplift. Furthermore, incremental dynamic analyses (IDAs) are performed to gain insights into the effects of the axial stiffness of the anchor bolts on the uplift of the tank. The uncertainties regarding the seismic input, i.e., the record-to-record variability and seismic intensity, are taken into account by selecting a set of near-field earthquake ground motion records with and without forward directivity. It should be noted that peak ground acceleration (PGA) is chosen as the intensity measure in IDAs. According to the results, using steel anchor bolts significantly reduces the uplift of the tank due to their high axial stiffness, which may result in a severe damage at the connection as a result of high axial forces in the bolts. Conversely, the self-centering feature of SMA anchor bolts allow the tank to undergo a limited uplift, which also leads to significant energy absorption. Furthermore, the Incremental dynamic analysis results show that tanks anchored with SMA bolts are less sensitive to the frequency content of the seismic input compared to the tanks anchored with steel bolts. Based on the findings of this research, it is possible to reduce the required diameter of the anchor bolts and eliminate the residual deformation of the anchorage system after a severe seismic event by using SMA anchor bolts. 10.34910/MCE.108.2 liquid storage tank SMA anchor bolts uplift incremental dynamic analysis (IDA) near-field earthquake records forward directivity https://engstroy.spbstu.ru/article/2021.108.2/
RAR RUS 10803-10803 0000-0002-0510-4015 Thuyloi University Ngo Van-Thuyet thuyet.kcct@tlu.edu.vn
175 Tay Son, Dong Da, Hanoi, Vietnam
 Effectiveness of base-isolated low-rise masonry building under excitation from earthquakes Low-rise masonry building is one of the most commonly adopted structural types even in earthquake prone regions in developing countries. The building is generally susceptible to damage due to earthquake induced motion and may suffer partial or total collapse. Un-bonded fiber reinforced elastomeric isolator (U-FREI) is a relatively new seismic base isolator and is expected to be an attractive option for seismic mitigation of low-rise buildings. In this paper, the effectiveness of a base-isolated masonry building supported on U-FREIs subjected to earthquakes is investigated by finite element (FE) analysis using SAP2000. The prototype building is a two-storey masonry building located at Tawang, Arunachal Pradesh State, India and is the first such U-FREIs supported prototype low-rise building constructed anywhere in the world. Mechanical characteristics of U-FREIs obtained from both experiments and FE analysis are utilized in defining the nonlinear property of the model used for simulating U-FREIs. The force-deformation behaviour of the isolator is modelled as bi-linear hysteretic behaviour, which can be effectively used to model all isolation system in practice. Time history analysis of the building for both fixed-base (FB) and base-isolated (BI) conditions under the action of various recorded real earthquakes are investigated. Comparison of the dynamic response of both FB and BI buildings is computed to evaluate the effectiveness of the base isolation system. The FE analysis results show that floor acceleration and inter-storey drift responses of the BI building under earthquakes are significantly lesser than those of the FB building. U-FREIs are recommended for seismic isolation of low-rise masonry building. 10.34910/MCE.108.3 masonry building base isolation seismic isolation technology seismic vulnerability fiber reinforced elastomeric isolator floor acceleration response inter-storey drift response earthquake https://engstroy.spbstu.ru/article/2021.108.3/
RAR RUS 10804-10804 0000-0003-2384-5439 Gayatri Vidya Parishad College of Engineering (Autonomous) Manchikanti Srinivas manchisri@gvpce.ac.in
Madhurawada, Visakhapatnam, India
 Gayatri Vidya Parishad College of Engineering (Autonomous) Pavan Kumar Rangabhatla manchisri@gvpce.ac.in
Madhurawada, Visakhapatnam, India
 Physical and mechanical properties of construction and demolition waste Construction and demolition waste is produced every day around the world posing a great disposal problem. Thus, the idea of using wastes in different forms appears to be an effective approach to waste disposal. The various materials that can be reclaimed from construction and demolition waste include recycled concrete aggregates (RCA), crushed brick (CB), reclaimed asphalt pavement (RAP), waste excavation rock (WR), fine recycled glass (FRG). The assessment of the recycled concrete aggregates is identified by performing various tests, which indicate physical, chemical and mechanical properties of the materials. The physical properties test results indicated that the recycled aggregates showed good performance in comparison with the natural ones. The results of the test assessing mechanical performance of concrete with recycled aggregates also indicated better performance when required measures are taken, such as (i) The aggregates to be used are obtained from recycled materials the sizes of the fine aggregates can be controlled as per the requirement during demolition process and by sieving. (ii) The water absorption capacity of the recycled fine aggregates is higher than the natural fine aggregates and this water absorption capacity can be reduced by wetting and drying the aggregates. (iii) The performance of recycled coarse aggregates can be enhanced by removal and separation of the old hardened mortar which adhered to the aggregates obtained post-demolition. (iv) The performance can also be enhanced by the usage of suitable commercially-available plasticiser to reduce the higher water absorption ratio of the recycled aggregates to attain the required strength. 10.34910/MCE.108.4 recycled aggregates construction and demolition waste concrete compressive strength https://engstroy.spbstu.ru/article/2021.108.4/
RAR RUS 10805-10805 0000-0002-5347-5443 Peoples' Friendship University of Russia (RUDN University) Abdo Shamseldin eng.shamseldin13@hotmail.com
Moscow, Russia
 https://orcid.org/0000-0003-2493-7255 Peoples' Friendship University of Russia (RUDN University) Galishnikova Vera galishnikova-vv@rudn.ru
Moscow, Russia
 0000-0001-5577-1513 Alexandria University Fawzy Ahmed engahmedfawzy90@yahoo.com
Alexandria, Egypt
 Properties of recycled aggregate pervious concrete modified with Styrene Butadiene Rubber Latex Pervious concrete is a type of concrete mixture that is usually used in pavement with a high range of interconnected voids between large aggregate particles. Herein, an experimental study was conducted in order to figure out the effect of replacing (5 %, 10 % and 15 %) of cement weight by the styrene-butadiene rubber latex (SBRL), in addition to the impact of replacing (0 %, 25 %, 50 %, 75 % and 100 %) of natural coarse aggregates by recycled ones on the mechanical properties of the pervious concrete. The focused parameters in this experimental study were divided into two parts, permeability indices (density, voids ratio and water permeability) and strength indices (compressive, splitting and flexural tensile strengths and concrete potential to degradation). Additionally, since the water permeability is the most important property in the pervious concrete, relations between water permeability and the other mentioned properties were deduced. Generally, it is noticed that the addition of SBRL positively affects the mechanical properties of the pervious concrete. However, there is a slight decrease in permeability indices. It is observed that the addition of 10 % of SBRL to the pervious concrete with 75 % recycled aggregate increased the 28 days compressive, splitting tensile and flexural tensile strength by 70.8 %, 49.4 % and 29.7 %, respectively. In addition, the results showed a reduction in the hardened voids content, water permeability and potential to degradation by 13.3 %, 11 % and 31.7 %, respectively. 10.34910/MCE.108.5 pervious concrete recycled aggregate styrene butadiene rubber latex water permeability mechanical properties degradation https://engstroy.spbstu.ru/article/2021.108.5/
RAR RUS 10806-10806 0000-0003-2797-9805 University of Sciences and Technology Houari Boumediene Cherfa Hayet ha_cherfa@yahoo.fr
Algiers, Algeria
 Laboratory of Environment, Water Geomechanics and Structures LEEGO, University of Sciences and Technology Houari Boumediene Nechnech Ammar nechnech_a@yahoo.fr
Algiers, Algeria
 Département of Civil Engineering, Akli Mohand Oulhadj Uviversity Bouira (UAMOB) Saoudi saoudinacira@gmail.com
Bouira, Algeria
 Laboratory of Environment, Water Geomechanics and Structures LEEGO, University of Sciences and Technology Houari Boumediene Ait Mokhtar Khedidja k.aitmokhtar@laposte.net
Algiers, Algeria
 Mechanical properties of slag sand mixture used in road pavements Today the road has become a necessity and an important factor in the economic and social development of nations. Algeria knows the realization of many grandiose road projects that required large quantities of noble materials such as aggregates and crushed sands and which unfortunately are becoming increasingly rare. The inability of Algerian quarries to supply these materials is a reason for the valorization of industrial waste and local materials that are in abundance. Among these materials, we find granulated slag and dune sand. Our study presents valorization of these two materials through a formulation and characterization of slag sand mixture composed of dune sand treated with different percentages of granulated blast furnace slag, which acts as a hydraulic binder. The results obtained show that this treatment improves the cohesion and mechanical properties of sand dune, which allows its use in road engineering, particularly in the pavement layers. 10.34910/MCE.108.6 mechanical properties local materials slag dune sand pavement road engineering https://engstroy.spbstu.ru/article/2021.108.6/
RAR RUS 10807-10807 0000-0002-5576-7095 Department of Civil Engineering, Indian Institute of Technology (BHU) Shendkar Mangeshkumar mangesh.shendkar94@gmail.com
India
 0000-0001-6089-6716 Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University Beiraghi Hamid h.beiraghi@msh-iau.ac.ir
Mahdishahr, Iran
 57190293831 Department of Civil Engineering, Indian Institute of Technology (BHU) Mandal Sasankasekhar smandal.civ@itbhu.ac.in
India
 Effect of irregularity on seismic design parameters of RC-infilled structures A four-storey reinforced concrete (RC) building is seismically evaluated with the incorporation of different irregularities. Three model systems have been considered, i.e., model I: (RC-infilled regular frame in X and Y direction), model II: (RC-infilled plan irregular frame in X and Y direction), and model III: (RC infilled vertical + plan irregular frame in X and Y direction). Adaptive pushover analyses have been carried out to evaluate the seismic performance of the structure by using seismostruct software incorporating inelastic material behaviour for concrete, steel, and infill walls. Infill walls have been modelled as “double strut nonlinear cyclic models”. The most up-to-date seismic design includes the nonlinearity in the structure through a response reduction factor (R). The ductility reduction factor and overstrength factor are the main components of the response reduction factor. These seismic design parameters were computed from the adaptive pushover analysis, and finally, the response reduction factor has been calculated for all models and compared with the value recommended by IS 1893 part-1 (2016). The result shows that the evaluated R-factors are higher than the value recommended by the BIS code. However, it is observed that R-values are higher than the corresponding values recommended in the BIS code when the irregularity present in the structures. 10.34910/MCE.108.7 masonry walls adaptive pushover analysis response reduction factor ductility irregularity seismic performance https://engstroy.spbstu.ru/article/2021.108.7/
UNK RUS 10808-10808 6504446571 0000-0001-6981-7420 Jordan University of Science and Technology Al-Rousan Rajai rzalrousan@just.edu.jo
Irbid, Jordan
 Behavior of CFT steel columns damaged by thermal shock Experimental evaluation of the structural behavior of concrete-filled tubular (CFT) circular steel columns under the combined effects of axial and cyclic lateral loads is costly and challenging. Therefore, this study provides a nonlinear finite element analysis (NLFEA) of fourteen models for thermal shock damaged CFT circular steel columns wrapped with various layers of carbon fiber reinforced polymer (CFRP) composites at its end region, which represents the critical location in terms of the lateral load capacity. Firstly, the column axial load was applied as the first loading step, and then the horizontal load was applied at the top of the column as displacement-controlled loading to guarantee the descending part of the load-displacement behavior. The intent is to confine the column end to avoid outward local buckling of the CFT column and thus developing high strength, larger net drift and more energy dissipation. The NLFEA models were properly calibrated and validated with reputable experimental results, followed by conducting a parametric study to assess the influence of the number of CFRP layers and the impact of thermal shock on the CFT circular steel column performance. For the modeled CFT circular steel column, the use of five to ten layers of CFRP composites resulted in a significant performance enhancement. However, the performance enhancements using 9 and 10 CFRP layers were comparable with 8 CFRP layers. In addition, it was found that the column axial load level significantly affects the CFT circular steel column behavior under lateral loading; better behavior as the axial load level increased. Strengthening of any CFT circular steel column must be optimized through proper NLFEA modeling and the findings of this study represent useful guidelines and methodology for the similar strengthening of CFT steel columns damaged by thermal shock. 10.34910/MCE.108.8 cyclic lateral loads fiber reinforced polymer nonlinear finite element analysis https://engstroy.spbstu.ru/article/2021.108.8/
RAR RUS 10809-10809 57216502974 0000-0002-2600-5526 Ondokuz Mayis University Dushimimana Aloys chenkodu432@gmail.com
Samsun, Turkey
 Pan African University Institute for Sciences, Technology and Innovation Singirankabo Edouard nkabo12edus@gmail.com
Juja, Nairobi
 0000-0001-7827-3090 Pan African University Institute for Sciences, Technology and Innovation Kathumbi Lilies Kathami 06lilies@gmail.com
Juja, Nairobi
 Effective seismic response control of buildings with sliding bearings A complete response investigation on behavior of conventional sliding bearings applicable to seismic-isolated structures has not yet been fully realized, while use of such bearings is a common practice. A Full Structural Response Investigation (FSRI) comprising energy dissipation, bearing’s effective and post-yield stiffness, displacements, story drifts, shear forces, accelerations and time instants for peak responses has been carried out on a ten-story RC building model with varied superstructure stiffness, and isolated by flat and curved surface sliders under different types of earthquakes. Disregarding some of the responses mentioned above FSRI can result in poor control of seismic isolation, since all the responses are observed to be affected by the type of earthquake and bearing’s slider surface. Furthermore, the findings demonstrate that seismic isolation may not provide all desired responses, and in some situations, some responses may need to be of first priority owing to their beneficial effects. 10.34910/MCE.108.9 Seismic isolation friction pendulum bearing flat surface slider restoring force energy dissipation superstructure acceleration story drift shear force near and far-fault ground motion https://engstroy.spbstu.ru/article/2021.108.9/
RAR RUS 10810-10810 57191381045 0000-0002-3021-8591 University of Asia Pacific Miah Md. Jihad jihad.miah@uap-bd.edu
Dhaka, Bangladesh
 57202125889 0000-0001-9112-4049 Technische Universität Dresden Miah Mohammad Shamim mmshamim@iubat.edu
Dresden, Germany
 International University of Business Agriculture and Technology Paul Suvash Chandra suvashpl@iubat.edu
Dhaka, Bangladesh
 57208875766 0000-0003-3321-7989 Monash University Malaysia Kong Sih Ying kong.sih.ying@monash.edu
Selangor, Malaysia
 https://orcid.org/0000-0002-6232-6642 Stellenbosch University Babafemi Adewumi John ajbabafemi@sun.ac.za
Stellenbosch, South Africa
 0000-0002-8246-2174 University of Asia Pacific Ali Md Kawsar kawsar.uap@gmail.com
Dhaka, Bangladesh
 0000-0002-9475-7869 University of Asia Pacific Patoary Md Munir Hossain 3dcometdesign@gmail.com
Dhaka, Bangladesh
 Waste iron powder as aggregate and binder in mortar production This paper study the feasibility of reusing waste iron powder (WIP) in mortar as both natural fine aggregate (NFA) and cement replacement material. Within this context, the physical and mechanical properties of mortar made with five percentage replacements of 0 %, 25 %, 50 %, 75 %, and 100 % for NFA by WIP and 0 %, 2.5 %, 5 %, 7.5 %, and 10 % for cement by fine waste iron powder (FWIP) are studied at 7, 14 and 28 days. Cube, briquette, and prism specimens for compression, tension, and flexural strength, respectively, tests were used. It is found that the workability decreases, and the density of mortar increase with the increased replacement percentage of NFA by WIP. The compressive, tensile, and flexural strength of mortar made with WIP are significantly higher than NFA. The maximum increase in strength of mortar is observed for 75 % WIP, which is 30 % for compressive, 35 % for tensile, and 37 % for flexural strength, respectively, relative to the control at 28 days. Conversely, when FWIP is used as a cement replacement material, all strength decreases with an increase in FWIP. The maximum decrease in strength is observed for 10 % FWIP, which is 40 % for compressive and tensile, and 16 % for flexural strength, accordingly, relative to the control at 28 days. The results presented in this study demonstrate that, to some extent, WIP and FWIP can be used in concrete/mortar production. Successful application of these waste materials may add economical benefit in the production of sustainable building material as well as conserve the natural aggregates. 10.34910/MCE.108.10 waste iron powder fine aggregate mortar compressive strength tensile strength flexural strength https://engstroy.spbstu.ru/article/2021.108.10/
RAR RUS 10811-10811 36637640300 0000-0002-2705-6528 Mataram University Kencanawati Ni Nyoman nkencanawati@unram.ac.id
Mataram, Indonesia
 Mataram University Rofaida Aryani aryanirofaida@unram.ac.id
Mataram, Indonesia
 Mataram University Sugiartha I Wayan sugiartha88@gmail.com
Mataram, Indonesia
 Mataram University Beriman Anfal anfalberiman27@gmail.com
Mataram, Indonesia
 Mataram University Putri Aisya Intan Tajina aisyaaintan@gmail.com
Mataram, Indonesia
 Properties of tropically sourced timber subjected to elevated temperature Char layer is an important parameter for the fire-resistance design of timber. The char-layer insulates the inner layer (core) from high temperature to prevent further damage due to fire. This paper assesses the post-fire properties of tropical solid and laminated timber originating from Indonesia. The species are white teak, bayur, rajumas, and sengon. The timber was exposed to fire at time interval of 30, 45, and 60 min. The temperature growth was set according to ISO 834 standard heating curve. The result shows that the average of charring rate of species with greater density and longer time of exposure is smaller than that of species with smaller density and shorter time of exposure. The charring rate of tropical solid and glulam timber has a linear inverse relationship to the density at each time of exposure. The average experimental data linear regression suggests that tropically sourced timber with a density of more than 400 kg/m3 meets the charring rate of European standard. However, all experimental results agree with the Australian standard. Furthermore, according to post-fire mechanical properties examination, the solid timber core shows increased strength after fire; meanwhile, a strength decrease exists in glulam core. 10.34910/MCE.108.11 Elevated temperature tropical hardwood charring rate timber glulam https://engstroy.spbstu.ru/article/2021.108.11/
RAR RUS 10812-10812 57192662909 0000-0003-0162-2699 Don State Technical University Mailyan Levon lrm@aaanet.ru
Rostov-on-Don, Russia
 57197736878 0000-0002-0364-5504 Don State Technical University Stel'makh Sergei sergej.stelmax@mail.ru
Rostov-on-Don, Russia
 57197730793 0000-0001-5376-247X Don State Technical University Shcherban' Evgenii au-geen@mail.ru
Rostov-on-Don, Russia
 Differential characteristics of concrete in centrifugally spun and vibrospun building structures This paper presents research into the variatropic structural characteristics of experimental circular-section concrete specimens as well as the related differential (varying depthwise) structural characteristics of concrete subjected to centrifugal spinning and vibrospinning. The researchers sought to assess how the production technology (centrifugal spinning or vibrospinning) could affect the differential (varying depthwise) characteristics of concrete: density; cube and prism axial compressive strength; ultimate axial compressive strain; axial tensile strength and tensile bending strength; ultimate axial tensile strain; the elastic modulus; the strain-stress curve for compression and tensioning. The researchers made and tested six basic centrifugally spun and vibrospun circular-section specimens that had an outer diameter D of 450 mm, an inner diameter d of 150 mm, and a total height H = 1200 mm. The manufacturing technology differed in the experiments, as the team used both centrifugal spinning and vibrospinning. Experimental research into the differential characteristics of centrifugally spun and vibrospun concrete aged 7, 28, and 180 days as exposed by compression and tension revealed that the outer concrete layer had the best characteristics, while the inner layer was the worst. The experiments thus back the three-layer model of the variatropic structure in centrifugally spun and vibrospun concrete. The following differentiation was observed in variatropic concrete: the outer layer had the best strength and elastic modulus, while being less deformable; the inner layer had the least strength and elastic modulus, while being more deformable; the mid-layer concrete was average in terms of everything. Stress-strain curves of centrifugally spun and vibrospun concrete did differ by layer, too, further proving that such concrete had a variatropic structure. The curves showed the greatest strength for the outer layer and the lowest for the inner layer, while the mid layer had average values. 10.34910/MCE.108.12 concretes mechanical properties compressive strength tensile strength bending strength elastic moduli strain-stress curves https://engstroy.spbstu.ru/article/2021.108.12/
RAR RUS 10813-10813 S-1676-2017 6507460407 0000-0002-8907-7869 Tashkent Institute of Irrigation and Agricultural Mechanization Engineers Mirsaidov Mirziyod theormir@mail.ru
39, Kori Niyoziy St., Tashkent, Uzbekistan, 100000
 55586710000 0000-0002-6498-5043 Tashkent Institute of Irrigation and Agricultural Mechanization Engineers Sultanov Takhirjon tz-sultanov@mail.ru
Tashkent, Republic of Uzbekistan
 57209303565 0000-0003-2070-0058 Tashkent Institute of Irrigation and Agricultural Mechanization Engineers Yarashov Javlon zhavlon.yarashov@bk.ru
Tashkent, Uzbekistan
 Strength of earth dams considering elastic-plastic properties of soil The paper provides a detailed analysis of known publications devoted to various models and methods, as well as the results of the study of the stress state of structures, taking into account the elastoplastic properties of soil. A mathematical model, methods, and an algorithm to assess the stress-strain state of earth dams were built considering elastoplastic properties of soil, inhomogeneous structural features and the filling level of the reservoir under various influences. A variational equation of the principle of virtual displacements, and the finite element method and the method of elastic solutions were used to solve the problem. The reliability assessment of the results obtained was verified by studying the practical convergence of various model problems. The stress-strain state of three earth dams (of different heights) was investigated taking into account the elastic, elastoplastic properties of soil at different filling levels of the reservoir. At that, various mechanical effects were revealed, i.e., the appearance of additional strains in the most stressed places inside the dam body, and the occurrence of significant plastic shear strain in the slope zones and the smoothing of the arch effect in the core zone. It was found that an account of elastoplastic properties of soil at a completely filled reservoir significantly changes the pattern of shear stresses distribution in the body of the dam, i.e. they increase both in the upper retaining prism and in the lower prism. 10.34910/MCE.108.13 optimal design earthquake engineering soil mechanic soil-structure interaction seismic response https://engstroy.spbstu.ru/article/2021.108.13/
RAR RUS 10814-10814 Earth Cryosphere Institute SB RAS Ivanov Konstantin sillicium@bk.ru Thermal conductivity of granular insulation in conditions of soil freezing Thermal insulation materials are widely used in engineering practice to reduce the depth of seasonal freezing. The effective thermal conductivity of the material is the main criterion for predicting the freezing depth of the structure base and determining the required thickness of the thermal insulation layer. However, the effective thermal conductivity of granular thermal insulation materials can significantly depend on the seasonal temperature, hydrological conditions of the soil and the degree of water content of the material. In this regard, calculating the effective thermal conductivity of granular thermal insulation materials in natural conditions is an urgent scientific and practical task. Granular foam-glass ceramic with a bulk density of 250 kg/m3 was used in the study. To solve the problem, we employed an experimental set to simulate the natural conditions of heat transfer in a horizontal layer, which makes it possible to change the magnitude and direction of the temperature gradient. It was established that the magnitude and direction of the temperature gradient have no significant influence on the layer of granules with a size of 5–10 mm. A predictive calculation of the temperature fields of the roadbed using experimental values depending on the water content degree was carried out. It was found that the depth of freezing of the roadbed covered with a 20 cm layer of foam-glass ceramic with effective thermal conductivity of 0.075, 0.111 and 0.138 W/(m·°C), respectively, is 12, 3.8 and 3 times lower than without the thermal insulation layer. A graphical interpretation of the temperature field in the form of -2°C isotherms shows that there is a dangerous zone of intense frost heaving with a depth of 58 cm forming at the roadbed without thermal insulation. Complete absence of zones of intense frost heaving in the roadbed covered with granular foam-glass ceramic was confirmed. 10.34910/MCE.108.14 insulating materials frost protection glass ceramics aggregates frozen soils https://engstroy.spbstu.ru/article/2021.108.14/
RAR RUS 10815-10815 0000-0002-1606-6456 Peter the Great St.Petersburg Polytechnic University Alhimenko Aleksey 9586435@mail.ru
St.Petersburg, Russia
 57204708134 Peter the Great St.Petersburg Polytechnic University Shaposhnikov Nikita shaposhn_no@spbstu.ru
St.Petersburg, Russia
 56989733400 Peter the Great St.Petersburg Polytechnic University Kharkov Alexander harkov_aa@spbstu.ru
St.Petersburg, Russia
 57211407884 0000-0001-9965-7966 Peter the Great St.Petersburg Polytechnic University Strekalovskaya Darya darya.strek@gmail.com
St.Petersburg, Russia
 57200040985 0000-0002-8996-1507 Peter the Great St.Petersburg Polytechnic University Alekseeva Ekaterina alexeeva__ekaterina@mail.ru
St.Petersburg, Russia
 57211409697 Peter the Great St.Petersburg Polytechnic University Kovalev Mark kovalev_ma@spbstu.ru
St.Petersburg, Russia
 Peter the Great St.Petersburg Polytechnic University Shishkova Margarita shishkova_ml@spbstu.ru
St.Petersburg, Russia
 Corrosion resistance of steel structures in marine conditions he article is devoted to the study of the corrosion resistance of steel pile supports made of pipe steel 09Mn2Si (09G2S), under conditions of cyclic wetting (conditional waterline), where conditions are created for the occurrence of corrosion processes at maximum speeds, and also a study of the protective ability of zinc coating applied to the railing (balustrade) of a steel bridge made of carbon steel of normal quality (St3). It was the bridge structures that became the subject of research. We considered the effects of cyclic wetting, wear, and climatic factors on the materials of piled supports, fences, and coatings intended for operation in the marine structure. We investigated the corrosion resistance of the 09Mn2Si steel used as pile supports of offshore structures. We have found that the corrosion rate of the 09Mn2Si steel does not exceed 0.32 mm/year in the zone of cyclic wetting. We have confirmed that the corrosion rate of steel practically does not change in the sections with damaged coatings and does not depend on the area of the uncoated zone. Measuring the electrochemical potential of 09Mn2Si steel, we have found that short-term friction against a solid only weakly affects the corrosion rate of steel in seawater. We have proposed a methodological approach to assessing the service life of hot-dip galvanized coatings on components of steel structures made of carbon steel of normal quality (St3) intended for operation in marine conditions. A forecast of the durability of 120 μm-thick zinc coatings, expected to provide anti-corrosion protection of steel products for 60 years, was made based on the proposed technique. 10.34910/MCE.108.15 steel corrosion corrosion rate corrosion resistance steel structures coating corrosion protection corrosion resistant coatings zinc coating marine environment https://engstroy.spbstu.ru/article/2021.108.15/