Pub Date : 2022-07-31DOI: 10.14311/cej.2022.02.0022
Zhang Huijian, Liu Gongning, Liu Weixiong, Miao Longgang
Topography is one of the important factors affecting the distribution of the self-weight stress field. However, granular materials are different from general continuum materials (such as fluids and solids). Only adopting the continuum theory research still has certain limitations, while the use of experimental methods can better reflect the actual stress state of the granular materials. Therefore, in order to further obtain the vertical self-weight stress distribution of single slope with granular materials, the indoor experimental study of quartz sand based on the point source method is carried out in this paper. The research results indicate that: The measured value of the vertical stress on the bottom surface of the quartz sand slope is generally smaller than the γh (Gravity × Buried depth) value of the corresponding point, and the closer the measuring point is to the slope top, the greater the difference between the test value and γh. Besides, the influence of slope heights and slope ratios on the vertical self-weight stress about slope with granular material is also analyzed. Stress depressions appear in some test conditions, that is, the measured stress peak on the bottom of the slope does not appear at the measuring point closest to the slope top. Whether there is a stress depression and the scope of the depression is mainly related to the slope height, while the slope ratio has little effect on it.
{"title":"EXPERIMENTAL STUDY ON THE VERTICAL SELF-WEIGHT STRESS DISTRIBUTION LAW OF SLOPE WITH GRANULAR MATERIALS UNDER DIFFERENT CONDITIONS","authors":"Zhang Huijian, Liu Gongning, Liu Weixiong, Miao Longgang","doi":"10.14311/cej.2022.02.0022","DOIUrl":"https://doi.org/10.14311/cej.2022.02.0022","url":null,"abstract":"Topography is one of the important factors affecting the distribution of the self-weight stress field. However, granular materials are different from general continuum materials (such as fluids and solids). Only adopting the continuum theory research still has certain limitations, while the use of experimental methods can better reflect the actual stress state of the granular materials. Therefore, in order to further obtain the vertical self-weight stress distribution of single slope with granular materials, the indoor experimental study of quartz sand based on the point source method is carried out in this paper. The research results indicate that: The measured value of the vertical stress on the bottom surface of the quartz sand slope is generally smaller than the γh (Gravity × Buried depth) value of the corresponding point, and the closer the measuring point is to the slope top, the greater the difference between the test value and γh. Besides, the influence of slope heights and slope ratios on the vertical self-weight stress about slope with granular material is also analyzed. Stress depressions appear in some test conditions, that is, the measured stress peak on the bottom of the slope does not appear at the measuring point closest to the slope top. Whether there is a stress depression and the scope of the depression is mainly related to the slope height, while the slope ratio has little effect on it.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89178648","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}
Pub Date : 2022-07-31DOI: 10.14311/cej.2022.02.0025
Espoir Kahama, Xie Fuzhe, Ali Abdulkadir Aden, Faisal Iliasu Illo
Defects emanating from the onsite operation of the grouted sleeve connector have a significant impact on the ultimate tensile capacity of the connector. In this research, an experiment on the capacity of the fully grouted sleeve connector considering different configurations of defects was carried out. The experiment results indicated that the connector is highly sensitive to the location of the defects, which engenders a drop of 15% in the ultimate capacity of the connector. Based on the accurate simulation of the experiment model, a series of parametric analyses were conducted to evaluate the interaction of defects with other mechanical properties of the connector. It was found that the different values of the ratio of the sleeve diameter to that of the bar within the design recommended interval significantly influence the connection's performance. The lowest ratio value engenders approximately 10% to 16% of tensile strength recovery in the weakened configuration, while a bigger ratio value engenders a decline in the capacity. This work proposes the incorporation of a safety constant in the average bond expression.
{"title":"STUDY ON THE INFLUENCE OF THE CONFINEMENT EFFECT ON THE BOND STRENGTH RECOVERY IN THE DEFECTIVE GROUTED SLEEVE CONNECTION","authors":"Espoir Kahama, Xie Fuzhe, Ali Abdulkadir Aden, Faisal Iliasu Illo","doi":"10.14311/cej.2022.02.0025","DOIUrl":"https://doi.org/10.14311/cej.2022.02.0025","url":null,"abstract":"Defects emanating from the onsite operation of the grouted sleeve connector have a significant impact on the ultimate tensile capacity of the connector. In this research, an experiment on the capacity of the fully grouted sleeve connector considering different configurations of defects was carried out. The experiment results indicated that the connector is highly sensitive to the location of the defects, which engenders a drop of 15% in the ultimate capacity of the connector. Based on the accurate simulation of the experiment model, a series of parametric analyses were conducted to evaluate the interaction of defects with other mechanical properties of the connector. It was found that the different values of the ratio of the sleeve diameter to that of the bar within the design recommended interval significantly influence the connection's performance. The lowest ratio value engenders approximately 10% to 16% of tensile strength recovery in the weakened configuration, while a bigger ratio value engenders a decline in the capacity. This work proposes the incorporation of a safety constant in the average bond expression.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"96 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81453048","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0003
Dien Vu Kim, Sofya Ildarovna Bazhenova, Trong-Chuc Nguyen, V. Tang, Minh Chien Do, Van Loi Le, V. D. Nguyen, C. Nguyen, Minh Thuan Hoang
The paper presents the blast furnace slag properties at different grinding times by the dry grinding method. The process of fine grinding blast furnace slag is prepared at different times (10 minutes, 20 minutes, 30 minutes, 40 minutes). The results indicated that the main component in BFS is the amorphous structure defined in about 25÷35 degrees (with the appearance of Akermanite at 31.1, Calcite at 29.2 and Aragonite at 26.4). The results also showed that the compressive strength and activity index of blast furnace slag increased significantly after extending the grinding time from 0-40 minutes (corresponding to compressive strength from 51.2 ÷ 7 2.1 MPa at 28 days of age and activity index of blast furnace slag from 91.92% -129.44%). The fine grinding process shows that the particle size of blast furnace slag is significantly reduced. In addition, the paper also presents the effect of finely ground blast furnace slag in 40 minutes on foam concrete properties. Research results show that the use of finely crushed blast furnace slag by the mechanical grinding method to replace sand in foam concrete not only improves the mechanical properties such as compressive strength, flexural strength, the elastic modulus of foam concrete but also protect the environment, reduce product costs.
{"title":"Blast furnace slag properties at different grinding times and its effect on foam concrete properties","authors":"Dien Vu Kim, Sofya Ildarovna Bazhenova, Trong-Chuc Nguyen, V. Tang, Minh Chien Do, Van Loi Le, V. D. Nguyen, C. Nguyen, Minh Thuan Hoang","doi":"10.14311/cej.2022.01.0003","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0003","url":null,"abstract":"The paper presents the blast furnace slag properties at different grinding times by the dry grinding method. The process of fine grinding blast furnace slag is prepared at different times (10 minutes, 20 minutes, 30 minutes, 40 minutes). The results indicated that the main component in BFS is the amorphous structure defined in about 25÷35 degrees (with the appearance of Akermanite at 31.1, Calcite at 29.2 and Aragonite at 26.4). The results also showed that the compressive strength and activity index of blast furnace slag increased significantly after extending the grinding time from 0-40 minutes (corresponding to compressive strength from 51.2 ÷ 7 2.1 MPa at 28 days of age and activity index of blast furnace slag from 91.92% -129.44%). The fine grinding process shows that the particle size of blast furnace slag is significantly reduced. \u0000In addition, the paper also presents the effect of finely ground blast furnace slag in 40 minutes on foam concrete properties. Research results show that the use of finely crushed blast furnace slag by the mechanical grinding method to replace sand in foam concrete not only improves the mechanical properties such as compressive strength, flexural strength, the elastic modulus of foam concrete but also protect the environment, reduce product costs.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73211756","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0005
R. Salini, C. Lenngren
In road industry, the construction of asphalt concrete layers is a dynamic process that, if not properly done, will lead to problems compromising the pavement performance. One of the most common problems is poor compaction leading to air-void volume above the maximum acceptable. This study discusses the impact of compaction/density deficiencies and presents an innovative model to calculate the asphalt pavement service-life loss in a simple and objective way, and in line with the road construction managers needs to calculate price penalty for contractors. The model was optimized for dense graded asphalt concrete, that typically has a maximum acceptable air‑void volume between 4% and 7%.
{"title":"HIGH AIR-VOID VOLUME IMPLICATIONS FOR ASPHALT CONCRETE SERVICE-LIFE AND PRICE PENALTY","authors":"R. Salini, C. Lenngren","doi":"10.14311/cej.2022.01.0005","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0005","url":null,"abstract":"In road industry, the construction of asphalt concrete layers is a dynamic process that, if not properly done, will lead to problems compromising the pavement performance. One of the most common problems is poor compaction leading to air-void volume above the maximum acceptable. This study discusses the impact of compaction/density deficiencies and presents an innovative model to calculate the asphalt pavement service-life loss in a simple and objective way, and in line with the road construction managers needs to calculate price penalty for contractors. The model was optimized for dense graded asphalt concrete, that typically has a maximum acceptable air‑void volume between 4% and 7%.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78142386","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0007
Abdelkadir Belghit, N. Bouhamou, M. Hamadache, Belkacem Ziregue
Reducing the amount of clinker in cement industry using Supplementary Cementitious Materials (SCMs) is one of the solutions developed by researchers in our field trying to respect environmental requirements, in the same context the present work aim to test the feasibility of new combinations using two sorts of Algerian SCMs and to evaluate their behavior while exposed to hydrochloric acid. To concretize this objective we fabricated a control mortar (based on cement CEMI) and nine other mortars containing modified cements, by a binary and ternary mixtures of Portland Cement CEMI, Calcined Mud (Wastes) of Chofa Dam (CW) and Natural Pouzzolana (NP), all these mixtures were tested at fresh state for consistency and setting time of pastes, and at hardened state for apparent density measure, water absorption and compressive strength of mortars. After that the ten of them were immersed in hydrochloric acid (HCL) 5% during fifteen weeks (105 days), Then they were examined for mass loss, volume loss, density decrease (apparent density) and the visual appearance. The results obtained in the majority of tests showed that the mixtures containing SCMs especially the ternary mixtures are realizable and more advantageous than others and characterized by a higher water demand and a better behavior after both compressive and HCL attack.
{"title":"THE HYDROCHLORIC ACID EFFECTS ON MODIFIED CEMENT WITH NEW COMBINATIONS BASED ON CALCINED DAM’S MUD AND NATURAL POUZZOLANA","authors":"Abdelkadir Belghit, N. Bouhamou, M. Hamadache, Belkacem Ziregue","doi":"10.14311/cej.2022.01.0007","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0007","url":null,"abstract":"Reducing the amount of clinker in cement industry using Supplementary Cementitious Materials (SCMs) is one of the solutions developed by researchers in our field trying to respect environmental requirements, in the same context the present work aim to test the feasibility of new combinations using two sorts of Algerian SCMs and to evaluate their behavior while exposed to hydrochloric acid. To concretize this objective we fabricated a control mortar (based on cement CEMI) and nine other mortars containing modified cements, by a binary and ternary mixtures of Portland Cement CEMI, Calcined Mud (Wastes) of Chofa Dam (CW) and Natural Pouzzolana (NP), all these mixtures were tested at fresh state for consistency and setting time of pastes, and at hardened state for apparent density measure, water absorption and compressive strength of mortars. After that the ten of them were immersed in hydrochloric acid (HCL) 5% during fifteen weeks (105 days), Then they were examined for mass loss, volume loss, density decrease (apparent density) and the visual appearance. The results obtained in the majority of tests showed that the mixtures containing SCMs especially the ternary mixtures are realizable and more advantageous than others and characterized by a higher water demand and a better behavior after both compressive and HCL attack.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90881229","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0001
P. Soroushian, A. Balachandra, R. Weerasiri, N. Darsanasiri, Nastran Abdol
Corrosion is a primary factor compromising the safety and service life of steel structures. Corrosion protection coatings are generally employed for protection of the steel structures that are exposed to different aggressive environments. This research evaluated the use of biobased ion exchangers as a sustainable means of improving corrosion protection coatings. Two base polymer coatings (vinyl and coal-tar epoxy) were considered. The following types and dosages of biobased ion exchangers were evaluated in these coatings: (i) strong-base ion exchange cellulose in OH, PO4, SiO3, BO3, NO2, SO4 and NO3 forms at 1% by weight of resin; (ii) weak-acid starch citrate ion exchanger in H form at 1 wt.%; and (iii) strong-base ion exchange cellulose in OH form at 2 wt.%. In addition, a strong-base ion exchange resin in OH form was considered at 1 and 2 wt.% as control. Different coating formulations were evaluated based on the outcomes of salt-fog corrosion, moisture resistance, pull-off strength, and abrasion resistance tests. The introduction of certain biobased ion exchangers in protective coatings was found to be an effective means of achieving improved levels of corrosion resistance, adhesion capacity, moisture stability and abrasion resistance.
{"title":"A SUSTAINABLE APPROACH TO IMPROVEMENT OF CORROSION PROTECTION COATINGS FOR STEEL STRUCTURES","authors":"P. Soroushian, A. Balachandra, R. Weerasiri, N. Darsanasiri, Nastran Abdol","doi":"10.14311/cej.2022.01.0001","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0001","url":null,"abstract":" Corrosion is a primary factor compromising the safety and service life of steel structures. Corrosion protection coatings are generally employed for protection of the steel structures that are exposed to different aggressive environments. This research evaluated the use of biobased ion exchangers as a sustainable means of improving corrosion protection coatings. \u0000Two base polymer coatings (vinyl and coal-tar epoxy) were considered. The following types and dosages of biobased ion exchangers were evaluated in these coatings: (i) strong-base ion exchange cellulose in OH, PO4, SiO3, BO3, NO2, SO4 and NO3 forms at 1% by weight of resin; (ii) weak-acid starch citrate ion exchanger in H form at 1 wt.%; and (iii) strong-base ion exchange cellulose in OH form at 2 wt.%. In addition, a strong-base ion exchange resin in OH form was considered at 1 and 2 wt.% as control. Different coating formulations were evaluated based on the outcomes of salt-fog corrosion, moisture resistance, pull-off strength, and abrasion resistance tests. The introduction of certain biobased ion exchangers in protective coatings was found to be an effective means of achieving improved levels of corrosion resistance, adhesion capacity, moisture stability and abrasion resistance.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88722798","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0012
Guojiang Zhang, G. Guo, Wei Wei, Sifeng Zhang, Gu Yao
In the western of china, the deep mining area with super-thick and weak cementation overburden is vast, sparsely populated and the ecological environment is extremely fragile. With the large-scale exploitation of deep coal resources, it is inevitable to face green mining problem, whose essence is the surface subsidence control. Therefore, it is necessary to study the control technology for the regional mining based on the evolution law of subsidence movement and energy-polling of super-thick and weak cementation overburden, and put forward the economically design scheme that can control strata movement and surface subsidence in a certain degree. Based on the key strata control theory, this paper puts forward the subsidence control scheme of partial filling -partial caving in multi-working face coordinated mining, and further studies its control mechanism through the numerical simulation and then analyzes the control effect of the strata movement and energy-polling in the fully caving mining, backfill mining, wide strip skip-mining and mixed filling mining method etc., the following conclusions are detailed as follows: (1) The maximum value of energy-polling occurs on the coal pillars or on both sides of goaf. With the width of goaf, the maximum value of energy-polling increases in a parabola. (2) In the partial filling-partial caving multiple working faces coordinated mining based on the main key stratum, the stress distribution of the composite backfill in the filling working face is parabolic, and it is high on both sides and low in the middle. Moreover, in the composite backfill, the stress concentration degree of a outside coal pillar is greater than that of the inside coal pillar. (3)The control mechanism of partial filling-partial caving harmonious mining based on main key layer structure is the double-control cooperative deformation system, formed by the composite backfill and the main and sub-key layers structure. They jointly control the movement and energy accumulation of overlying strata by greatly reducing the effective space to transmit upward, and absorb the wave subsidence trend of the overburden until it develops into a single flat subsidence basin. (4) Considering the recovery rate, pillar rate, area filling rate, technical difficulty and subsidence coefficient etc., the partial filling-partial caving multiple working faces coordinated mining based on the main key stratum is the most cost-effective mining method to control surface subsidence. This paper takes a guiding role in controlling the regional strata movement and surface subsidence of deep mining with super-thick and weak cementation overburden.
{"title":"A NEW METHOD TO CONTROL THE REGIONAL STRATA MOVEMENT OF SUPER-THICK WEAK CEMENTATION OVERBURDEN IN DEEP MINING","authors":"Guojiang Zhang, G. Guo, Wei Wei, Sifeng Zhang, Gu Yao","doi":"10.14311/cej.2022.01.0012","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0012","url":null,"abstract":"In the western of china, the deep mining area with super-thick and weak cementation overburden is vast, sparsely populated and the ecological environment is extremely fragile. With the large-scale exploitation of deep coal resources, it is inevitable to face green mining problem, whose essence is the surface subsidence control. Therefore, it is necessary to study the control technology for the regional mining based on the evolution law of subsidence movement and energy-polling of super-thick and weak cementation overburden, and put forward the economically design scheme that can control strata movement and surface subsidence in a certain degree. Based on the key strata control theory, this paper puts forward the subsidence control scheme of partial filling -partial caving in multi-working face coordinated mining, and further studies its control mechanism through the numerical simulation and then analyzes the control effect of the strata movement and energy-polling in the fully caving mining, backfill mining, wide strip skip-mining and mixed filling mining method etc., the following conclusions are detailed as follows: (1) The maximum value of energy-polling occurs on the coal pillars or on both sides of goaf. With the width of goaf, the maximum value of energy-polling increases in a parabola. (2) In the partial filling-partial caving multiple working faces coordinated mining based on the main key stratum, the stress distribution of the composite backfill in the filling working face is parabolic, and it is high on both sides and low in the middle. Moreover, in the composite backfill, the stress concentration degree of a outside coal pillar is greater than that of the inside coal pillar. (3)The control mechanism of partial filling-partial caving harmonious mining based on main key layer structure is the double-control cooperative deformation system, formed by the composite backfill and the main and sub-key layers structure. They jointly control the movement and energy accumulation of overlying strata by greatly reducing the effective space to transmit upward, and absorb the wave subsidence trend of the overburden until it develops into a single flat subsidence basin. (4) Considering the recovery rate, pillar rate, area filling rate, technical difficulty and subsidence coefficient etc., the partial filling-partial caving multiple working faces coordinated mining based on the main key stratum is the most cost-effective mining method to control surface subsidence. This paper takes a guiding role in controlling the regional strata movement and surface subsidence of deep mining with super-thick and weak cementation overburden.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86940736","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0011
Abigail Klejchová, M. Dohnal, M. Tesař
The snow water equivalent is an important snow characteristic as it provides hydrologically relevant information on the amount of water stored in the snowpack. The experimental catchment in the Jizera Mountains was equipped with the gamma-ray spectroscope CS725. The sensor uses emitted electromagnetic signals of isotopes 40K and 208Tl to remotely and continuously measure the snow water equivalent (SWE). Two winter seasons, 2018-2019 and 2019-2020 were monitored, and the obtained data were analyzed together with the complementary measurements available (snow depth, precipitation, air temperature). The sensor was tested in contrasting conditions of the precipitation-rich winter period 2018-2019 and the mild winter period 2019-2020. Our measurement showed that the SWE values derived from both isotopes are very similar and logically correspond well with the other measurements at the site. As far as we know, the first use of the sensor in the Czech Republic has proven usability in the conditions of the temperate montane catchment.
{"title":"USE OF PROXIMAL GAMMA-RAY SPECTROSCOPY FOR NEAR REAL-TIME DETECTION OF SNOW WATER EQUIVALENT IN JIZERA MTS.","authors":"Abigail Klejchová, M. Dohnal, M. Tesař","doi":"10.14311/cej.2022.01.0011","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0011","url":null,"abstract":"The snow water equivalent is an important snow characteristic as it provides hydrologically relevant information on the amount of water stored in the snowpack. The experimental catchment in the Jizera Mountains was equipped with the gamma-ray spectroscope CS725. The sensor uses emitted electromagnetic signals of isotopes 40K and 208Tl to remotely and continuously measure the snow water equivalent (SWE). Two winter seasons, 2018-2019 and 2019-2020 were monitored, and the obtained data were analyzed together with the complementary measurements available (snow depth, precipitation, air temperature). The sensor was tested in contrasting conditions of the precipitation-rich winter period 2018-2019 and the mild winter period 2019-2020. Our measurement showed that the SWE values derived from both isotopes are very similar and logically correspond well with the other measurements at the site. As far as we know, the first use of the sensor in the Czech Republic has proven usability in the conditions of the temperate montane catchment.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74080943","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0015
Z. Poloprutský, Eva Frommeltová, Josef Münzberger, Kateřina Sedlická
This paper deals with the specifics and working procedures for 3D digital reconstructions of defunct buildings of rural architecture. The resulting 3D models are to be used for presentation and educational activities intended for the lay and professional public and are based on archival sources - archival 2D metric survey documentation (drawings and photographs), written sources. Another requirement is the possibility of presentation on the internet within a parallel developing web platform. SketchUp 2021 Pro software, extended by plug-ins, is used for the 3D modelling process.
{"title":"3D DIGITAL RECONSTRUCTION OF DEFUNCT RURAL BUILDINGS BASED ON ARCHIVAL SOURCES","authors":"Z. Poloprutský, Eva Frommeltová, Josef Münzberger, Kateřina Sedlická","doi":"10.14311/cej.2022.01.0015","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0015","url":null,"abstract":"This paper deals with the specifics and working procedures for 3D digital reconstructions of defunct buildings of rural architecture. The resulting 3D models are to be used for presentation and educational activities intended for the lay and professional public and are based on archival sources - archival 2D metric survey documentation (drawings and photographs), written sources. Another requirement is the possibility of presentation on the internet within a parallel developing web platform. SketchUp 2021 Pro software, extended by plug-ins, is used for the 3D modelling process.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89349668","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}
Pub Date : 2022-04-30DOI: 10.14311/cej.2022.01.0008
Long Liu, Songqiang Wan, Shuwen Yao, Xinzhen Zhao, Jinyan Ma
UHPC is different from ordinary concrete for mechanical properties. To study the stress state of stud connector when UHPC is used to strengthen RC beam and its influence on bearing capacity of the strengthened beam, in this paper, ABAQUS was adopted first to simulate the push-out test of stud to verify accuracy of the finite element model. The nonlinearity of materials and contact conditions was considered in the model, and then three parameters including concrete strength, stud length and stud diameter were studied. Results showed the finite element model established by surface to surface contact method was possible to simulate the force and failure of the stud connector. UHPC could improve the bearing capacity of the stud specimens obviously, and the length of stud had little effect on bearing capacity of stud while failure of the stud may occur if length of the stud was too small. The increase of stud diameter could improve bearing capacity of elastic working stage.
{"title":"FINITE ELEMENT ANALYSIS OF MECHANICAL PROPERTIES OF SPECIMEN WITH UHPC AND STUD CONNECTOR","authors":"Long Liu, Songqiang Wan, Shuwen Yao, Xinzhen Zhao, Jinyan Ma","doi":"10.14311/cej.2022.01.0008","DOIUrl":"https://doi.org/10.14311/cej.2022.01.0008","url":null,"abstract":"UHPC is different from ordinary concrete for mechanical properties. To study the stress state of stud connector when UHPC is used to strengthen RC beam and its influence on bearing capacity of the strengthened beam, in this paper, ABAQUS was adopted first to simulate the push-out test of stud to verify accuracy of the finite element model. The nonlinearity of materials and contact conditions was considered in the model, and then three parameters including concrete strength, stud length and stud diameter were studied. Results showed the finite element model established by surface to surface contact method was possible to simulate the force and failure of the stud connector. UHPC could improve the bearing capacity of the stud specimens obviously, and the length of stud had little effect on bearing capacity of stud while failure of the stud may occur if length of the stud was too small. The increase of stud diameter could improve bearing capacity of elastic working stage.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90835800","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}
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