Pub Date : 2022-12-31DOI: 10.14311/cej.2022.04.0039
Z. Varilová, Kamil Podroužek, Natálie Belisová, J. Horák
The paper presents partial results of the expert cooperation between geologists and historians in the Bohemian Switzerland (Elbe Sandstones) area focused on mapping and documentation of old quarries and mining pits. More than three thousand abandoned quarries for building stone were newly mapped and registered within the study area. Attention was given not only to the preserved relics after mining and their historical context: methods of stone extraction were also described, and the current state of quarries and mining areas was documented. Many of them represent unstable quarry faces prone to rockfall. Catastrophic events have already occurred in some quarries, and some localities had to be technically secured by stabilizing works recently. One of the aims was therefore to create an inventory map of risk related to old quarries and the assessment of the present-day degree of instability. Fresh rockfalls from 2021/2022 were also registered. Three-dimensional models of selected quarry faces were created using modern technology including calculation of cubic capacity of excavated material and collapsed masses. The complete results are included in the map geodatabase, which is under construction.
{"title":"STABILITY DETERIORATION OF CLIFF FACES DUE TO HISTORICAL MINING IN THE ELBE SANDSTONES PROTECTED AREA","authors":"Z. Varilová, Kamil Podroužek, Natálie Belisová, J. Horák","doi":"10.14311/cej.2022.04.0039","DOIUrl":"https://doi.org/10.14311/cej.2022.04.0039","url":null,"abstract":"The paper presents partial results of the expert cooperation between geologists and historians in the Bohemian Switzerland (Elbe Sandstones) area focused on mapping and documentation of old quarries and mining pits. More than three thousand abandoned quarries for building stone were newly mapped and registered within the study area. Attention was given not only to the preserved relics after mining and their historical context: methods of stone extraction were also described, and the current state of quarries and mining areas was documented. Many of them represent unstable quarry faces prone to rockfall. Catastrophic events have already occurred in some quarries, and some localities had to be technically secured by stabilizing works recently. One of the aims was therefore to create an inventory map of risk related to old quarries and the assessment of the present-day degree of instability. Fresh rockfalls from 2021/2022 were also registered. Three-dimensional models of selected quarry faces were created using modern technology including calculation of cubic capacity of excavated material and collapsed masses. The complete results are included in the map geodatabase, which is under construction.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78434850","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0030
Jiawei Wang, Bing Cao, B. Huang, Yihan Du
As a new construction method, the bridge horizontal rotation construction method can reduce the impact of traffic under the bridge. During the horizontal rotation of the bridge, the overall structure will inevitably lead to a vibration response due to the construction error of the contact surface of the spherical hinge. Due to the large weight of the structure and the longer cantilever of the superstructure, the vibration at the spherical hinge will be amplified at the girder end, which will adversely affect the stability of the structure. Taking a 10,000-ton rotating bridge as a reference, a scaled model was made to test the vibration of the girder during the rotating process of the horizontal rotating system.And by analyzing the frequency domain curve of girder vibration and the results of simulation calculation, it is found that the vertical vibration displacement response is related to the first three modes of longitudinal bending of the girder structure, but has nothing to do with the higher modes or other modes. Applying the harmonic response analysis module in ANSYS software method, it is proposed that the structural vibration effect will reach the smallest by controlling the rotating speed in order to control the excitation frequency within the first-order mode frequency of girder. Also in this research, the expression of the relationship between the vertical vibration velocity and acceleration of the girder end of the horizontal rotation system and the vibration frequency of the girder is established. Based on that, it is proposed that the stability of the horizontal rotation can be predicted by monitoring the vertical velocity and acceleration of the cantilever girder end during the horizontal rotation.
{"title":"EXPERIMENTAL RESEARCH ON THE VIBRATION CHARACTERISTICS OF BRIDGE'S HORIZONTAL ROTATION SYSTEM","authors":"Jiawei Wang, Bing Cao, B. Huang, Yihan Du","doi":"10.14311/cej.2022.03.0030","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0030","url":null,"abstract":"As a new construction method, the bridge horizontal rotation construction method can reduce the impact of traffic under the bridge. During the horizontal rotation of the bridge, the overall structure will inevitably lead to a vibration response due to the construction error of the contact surface of the spherical hinge. Due to the large weight of the structure and the longer cantilever of the superstructure, the vibration at the spherical hinge will be amplified at the girder end, which will adversely affect the stability of the structure. Taking a 10,000-ton rotating bridge as a reference, a scaled model was made to test the vibration of the girder during the rotating process of the horizontal rotating system.And by analyzing the frequency domain curve of girder vibration and the results of simulation calculation, it is found that the vertical vibration displacement response is related to the first three modes of longitudinal bending of the girder structure, but has nothing to do with the higher modes or other modes. Applying the harmonic response analysis module in ANSYS software method, it is proposed that the structural vibration effect will reach the smallest by controlling the rotating speed in order to control the excitation frequency within the first-order mode frequency of girder. Also in this research, the expression of the relationship between the vertical vibration velocity and acceleration of the girder end of the horizontal rotation system and the vibration frequency of the girder is established. Based on that, it is proposed that the stability of the horizontal rotation can be predicted by monitoring the vertical velocity and acceleration of the cantilever girder end during the horizontal rotation.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91226340","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0037
Suchun Yang, Qiang Chen, S. Bie, Fubo He
In order to improve the evaluation ability of bearing capacity of offshore large-diameter monopile, the initial high strain detection and repeated high strain detection with an interval of 10-84 days were carried out on 6 large-diameter monopiles with a diameter of 7.2m-7.4m in the offshore wind field dominated by cohesive soil layer. The results show that the time-dependent increase of tip resistance, pile side resistance and total resistance of large-diameter monopiles in the same offshore wind farm has great discreteness, and the axial force increment of pile has a consistent change trend. This paper puts forward the prediction interval of 95% guarantee rate of bearing capacity increment of offshore large-diameter single pile based on depth, which provides a basis for the design of large-diameter monopile.
{"title":"Study on time effect of bearing capacity of Offshore Large Diameter Monopiles","authors":"Suchun Yang, Qiang Chen, S. Bie, Fubo He","doi":"10.14311/cej.2022.03.0037","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0037","url":null,"abstract":"In order to improve the evaluation ability of bearing capacity of offshore large-diameter monopile, the initial high strain detection and repeated high strain detection with an interval of 10-84 days were carried out on 6 large-diameter monopiles with a diameter of 7.2m-7.4m in the offshore wind field dominated by cohesive soil layer. The results show that the time-dependent increase of tip resistance, pile side resistance and total resistance of large-diameter monopiles in the same offshore wind farm has great discreteness, and the axial force increment of pile has a consistent change trend. This paper puts forward the prediction interval of 95% guarantee rate of bearing capacity increment of offshore large-diameter single pile based on depth, which provides a basis for the design of large-diameter monopile.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88519905","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}
In the bending process of semi-parallel steel wire cable, with the increase of the lateral displacement of the bending, the interaction between the steel wires in the cable is remarkable and the mechanical behavior is complicated. In order to study the mechanical behavior of the contact friction between the inner steel wires in the process of cable bending, this paper uses the 37-φ7 semi-parallel steel wire as the research object, and uses the ANSYS to set up the finite element model of the cable bending, and verifies the correctness of the refined finite element model by bending test data. Based on the refined finite element model of the test data verification, the variation rule of the contact friction between the inner steel wires in the semi-parallel steel wire of different boundary conditions in the bending process is studied, and the axial sliding behavior of the steel wires in the cable bending process is analyzed. The results show that the bending and mechanical properties of the semi-parallel steel wire cable can be calculated more accurately by considering the refined finite element model of the contact friction, and the amount of deformation between the steel wires during the bending process of the semi-parallel steel wire cable can be calculated. The contact pressure and the contact friction stress are non-linear with the increase of the lateral displacement of the bending, and there is a maximum value for the contact friction stress for the pre-tension semi-parallel wire cable, and the maximum position of the axial accumulated slip amount between the steel wires is located at the bending cable section of the calculated span of 1/4 or 3/4 times.
{"title":"ANALYSIS OF CONTACT FRICTION BEHAVIOR IN THE BENDING PROCESS OF SEMI-PARALLEL STEEL WIRE CABLE","authors":"Jianxi Yang, Hongyu Fei, Quansheng Sun, Xiang Wei Hao","doi":"10.14311/cej.2022.03.0034","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0034","url":null,"abstract":"In the bending process of semi-parallel steel wire cable, with the increase of the lateral displacement of the bending, the interaction between the steel wires in the cable is remarkable and the mechanical behavior is complicated. In order to study the mechanical behavior of the contact friction between the inner steel wires in the process of cable bending, this paper uses the 37-φ7 semi-parallel steel wire as the research object, and uses the ANSYS to set up the finite element model of the cable bending, and verifies the correctness of the refined finite element model by bending test data. Based on the refined finite element model of the test data verification, the variation rule of the contact friction between the inner steel wires in the semi-parallel steel wire of different boundary conditions in the bending process is studied, and the axial sliding behavior of the steel wires in the cable bending process is analyzed. The results show that the bending and mechanical properties of the semi-parallel steel wire cable can be calculated more accurately by considering the refined finite element model of the contact friction, and the amount of deformation between the steel wires during the bending process of the semi-parallel steel wire cable can be calculated. The contact pressure and the contact friction stress are non-linear with the increase of the lateral displacement of the bending, and there is a maximum value for the contact friction stress for the pre-tension semi-parallel wire cable, and the maximum position of the axial accumulated slip amount between the steel wires is located at the bending cable section of the calculated span of 1/4 or 3/4 times.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86325137","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0032
Ming-yi Zhang, Nannan Li, Min Yang
When the surcharge preloading method is used in the treatment of soft soil subgrade, it is necessary to squeeze for more preloading drainage consolidation time under the premise of controlling the subgrade stability during the filling period. Considering the mutation of each monitoring indices and their interrelation when instability occurs in the fill subgrade, the inflection point analysis method through monitoring indices to control the subgrade stability comprehensively was proposed in this paper. The thin-layer rotary adding method was used to determine the ultimate filling depth and the loading plan for the highway soft soil subgrade during the filling period, with the inflection point analysis method in analyzing and evaluating the subgrade stability. The results showed that: (1) The ultimate fill height of the subgrade sections was obtained from the stability analysis results on the basis of the three indices of pore water pressure increment, settlement and lateral displacement, which was close to the prediction results of the thin-layer rotary adding method. (2) The stability control standard of the subgrade construction in the filling method was that the single-stage pore pressure coefficient should be within 1.2. (3) The subgrade stability control standard contained the maximum settlement rate of 20mm/d and the maximum lateral displacement rate of 3mm/d. (4) The geotextile setting in the highway subgrade effectively improved the ultimate bearing capacity of the subgrade, reduced the lateral displacement, improved the anti-slip stability, and increased the ultimate filling height and filling rate.
{"title":"THE MULTI-FACTOR CONTROL AND EVALUATION OF HIGHWAY SOFT SOIL SUBGRADE STABILITY","authors":"Ming-yi Zhang, Nannan Li, Min Yang","doi":"10.14311/cej.2022.03.0032","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0032","url":null,"abstract":"When the surcharge preloading method is used in the treatment of soft soil subgrade, it is necessary to squeeze for more preloading drainage consolidation time under the premise of controlling the subgrade stability during the filling period. Considering the mutation of each monitoring indices and their interrelation when instability occurs in the fill subgrade, the inflection point analysis method through monitoring indices to control the subgrade stability comprehensively was proposed in this paper. The thin-layer rotary adding method was used to determine the ultimate filling depth and the loading plan for the highway soft soil subgrade during the filling period, with the inflection point analysis method in analyzing and evaluating the subgrade stability. The results showed that: (1) The ultimate fill height of the subgrade sections was obtained from the stability analysis results on the basis of the three indices of pore water pressure increment, settlement and lateral displacement, which was close to the prediction results of the thin-layer rotary adding method. (2) The stability control standard of the subgrade construction in the filling method was that the single-stage pore pressure coefficient should be within 1.2. (3) The subgrade stability control standard contained the maximum settlement rate of 20mm/d and the maximum lateral displacement rate of 3mm/d. (4) The geotextile setting in the highway subgrade effectively improved the ultimate bearing capacity of the subgrade, reduced the lateral displacement, improved the anti-slip stability, and increased the ultimate filling height and filling rate.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"146 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79960695","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0033
Qingming Xiang, Youqian Gao, Jiaxuan Su, Xiaoshuang Li, Xuansheng Cheng
In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form.
{"title":"STRATA SUBSIDENCE CHARACTERISTICS OF SHIELD TUNNELING IN COASTAL SOFT SOIL AREA","authors":"Qingming Xiang, Youqian Gao, Jiaxuan Su, Xiaoshuang Li, Xuansheng Cheng","doi":"10.14311/cej.2022.03.0033","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0033","url":null,"abstract":"In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89443572","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0038
Wei Fang, Huijian Zhang, S. Gao, Yuchao Zheng, Liu Gongning
At present, the research considering multi-factor softening conditions is rarely performed, and the research on the deformation law and mechanical properties of the tunnel in diatomite is even rarer. Diatomite is easy to soften in water, and its physical and mechanical properties change greatly after softening. Therefore, take the high-speed railway tunnel that passes through the diatomite stratum in East China as an example, considering various softening conditions (including softening degree and softening position), the deformation law and mechanical characteristics of the tunnel are obtained, and corresponding suggestions are also put forward according to different softening conditions. The results show that the deformation law and mechanical characteristics of the tunnel are greatly affected by the symmetry of softening part. The deformation of the inverted arch caused by the lower surrounding rock softening of the tunnel is the largest, and the maximum stress occurs at the arch foot when the upper surrounding rock of the tunnel softens. Different softening degrees and positions have a great influence on the mechanical characteristics and deformation law of the tunnel. The results obtained in this paper may provide some important references for similar projects in the future.
{"title":"Mechanical characteristics and deformation law of tunnel in diatomite considering various softening conditions","authors":"Wei Fang, Huijian Zhang, S. Gao, Yuchao Zheng, Liu Gongning","doi":"10.14311/cej.2022.03.0038","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0038","url":null,"abstract":"At present, the research considering multi-factor softening conditions is rarely performed, and the research on the deformation law and mechanical properties of the tunnel in diatomite is even rarer. Diatomite is easy to soften in water, and its physical and mechanical properties change greatly after softening. Therefore, take the high-speed railway tunnel that passes through the diatomite stratum in East China as an example, considering various softening conditions (including softening degree and softening position), the deformation law and mechanical characteristics of the tunnel are obtained, and corresponding suggestions are also put forward according to different softening conditions. The results show that the deformation law and mechanical characteristics of the tunnel are greatly affected by the symmetry of softening part. The deformation of the inverted arch caused by the lower surrounding rock softening of the tunnel is the largest, and the maximum stress occurs at the arch foot when the upper surrounding rock of the tunnel softens. Different softening degrees and positions have a great influence on the mechanical characteristics and deformation law of the tunnel. The results obtained in this paper may provide some important references for similar projects in the future.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78436918","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0029
Sukang Wang, Sun Quansheng, Yu Haitao, Wang Hongyang
Due to the swivel construction, the structural redundancy of cable-stayed bridge is reduced, and its seismic vulnerability is significantly higher than that of non-swirling construction structure and its own state of formation. Therefore, it is particularly important to study the damage changes of each component and stage system during the swivel construction of cable-stayed bridge under different horizontal earthquakes. Based on the construction of Rotary Cable-stayed Bridge in Haxi Street, the calculation formula of damage exceeding probability is established based on reliability theory, and the damage calibration of cable-stayed bridge components is carried out, and the finite element model of cable-stayed bridge rotating structure is established. The vulnerable parts of the main tower and the stay cable components of the cable-stayed bridge are identified and the incremental dynamic analysis is carried out. Finally, the seismic vulnerability curves of the main tower section, the stay cable and the rotating system are established. The results of the study show that the vulnerable areas of the H-shaped bridge towers are the abrupt changes in the main tower section near the upper and lower beams, and the vulnerable diagonal cables are the long cables anchored to the beam ends and the short cables near the main tower；At the same seismic level, the damage exceedance probability of main tower vulnerable section of cable-stayed bridge under transverse earthquake is greater than that under longitudinal earthquake, the damage exceedance probability of vulnerable stay cables under transverse seismic action is less than that under longitudinal seismic action；On the premise of the same damage probability, the required ground motion intensity of the system can be reduced by 0.35g at most compared with the component；Under the same seismic intensity, the system damage probability is 6.60 % higher than the component damage probability at most. The research results have reference significance for the construction of rotating cable-stayed bridges in areas lacking seismic records.
{"title":"SEISMIC VULNERABILITY ANALYSIS OF CABLE-STAYED BRIDGE DURING ROTATION CONSTRUCTION","authors":"Sukang Wang, Sun Quansheng, Yu Haitao, Wang Hongyang","doi":"10.14311/cej.2022.03.0029","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0029","url":null,"abstract":" Due to the swivel construction, the structural redundancy of cable-stayed bridge is reduced, and its seismic vulnerability is significantly higher than that of non-swirling construction structure and its own state of formation. Therefore, it is particularly important to study the damage changes of each component and stage system during the swivel construction of cable-stayed bridge under different horizontal earthquakes. Based on the construction of Rotary Cable-stayed Bridge in Haxi Street, the calculation formula of damage exceeding probability is established based on reliability theory, and the damage calibration of cable-stayed bridge components is carried out, and the finite element model of cable-stayed bridge rotating structure is established. The vulnerable parts of the main tower and the stay cable components of the cable-stayed bridge are identified and the incremental dynamic analysis is carried out. Finally, the seismic vulnerability curves of the main tower section, the stay cable and the rotating system are established. The results of the study show that the vulnerable areas of the H-shaped bridge towers are the abrupt changes in the main tower section near the upper and lower beams, and the vulnerable diagonal cables are the long cables anchored to the beam ends and the short cables near the main tower；At the same seismic level, the damage exceedance probability of main tower vulnerable section of cable-stayed bridge under transverse earthquake is greater than that under longitudinal earthquake, the damage exceedance probability of vulnerable stay cables under transverse seismic action is less than that under longitudinal seismic action；On the premise of the same damage probability, the required ground motion intensity of the system can be reduced by 0.35g at most compared with the component；Under the same seismic intensity, the system damage probability is 6.60 % higher than the component damage probability at most. The research results have reference significance for the construction of rotating cable-stayed bridges in areas lacking seismic records.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89292007","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0035
Yao Liu, Jintian Chen, Wu Li
With the over-exploitation of high-quality coastlines, the site selection and construction of new ports have to be expanded to silt coast, which will bring about quite many technical difficulties in the construction of wharves and revetments, and the cost of investment will also rise sharply. In this paper, a kind of combined design scheme of the high-pile wharf and the bucket structure is proposed to solve the problems mentioned above. The high-pile wharf structure is meant to adapt to the silt foundation, while the bucket can help to improve the ground bearing capacity. The stability and displacement of the bucket structure, and the influence of displacement on high-pile wharf during the service period are analyzed using a finite element model. Analysis results indicate that the horizontal and vertical displacements of the bucket structure in the service period are reduced to sme extent compared with those in the construction period, and the maximum horizontal displacements of the lower barrel structure are 0.4cm more than those of the upper part.The difference between the vertical displacement on the seaside and the portside is 10.5cm, and a rotation of 0.2° occurred in the bucket. Besides, the working loads above the bucket have a significant influence on the horizontal displacement and sliding stability of the bucket in the service period. It can be known from the above conclusion that the composite structure is a kind of structure that can adapt to the conditions of soft soil underwater, and it has advantages of the construction period and cost when used in water depth and silt area, which provides useful experience for the silt coastal projects.
{"title":"Research on the application of Pile-bucket composite structure in the Silt Coast","authors":"Yao Liu, Jintian Chen, Wu Li","doi":"10.14311/cej.2022.03.0035","DOIUrl":"https://doi.org/10.14311/cej.2022.03.0035","url":null,"abstract":"With the over-exploitation of high-quality coastlines, the site selection and construction of new ports have to be expanded to silt coast, which will bring about quite many technical difficulties in the construction of wharves and revetments, and the cost of investment will also rise sharply. In this paper, a kind of combined design scheme of the high-pile wharf and the bucket structure is proposed to solve the problems mentioned above. The high-pile wharf structure is meant to adapt to the silt foundation, while the bucket can help to improve the ground bearing capacity. The stability and displacement of the bucket structure, and the influence of displacement on high-pile wharf during the service period are analyzed using a finite element model. Analysis results indicate that the horizontal and vertical displacements of the bucket structure in the service period are reduced to sme extent compared with those in the construction period, and the maximum horizontal displacements of the lower barrel structure are 0.4cm more than those of the upper part.The difference between the vertical displacement on the seaside and the portside is 10.5cm, and a rotation of 0.2° occurred in the bucket. Besides, the working loads above the bucket have a significant influence on the horizontal displacement and sliding stability of the bucket in the service period. It can be known from the above conclusion that the composite structure is a kind of structure that can adapt to the conditions of soft soil underwater, and it has advantages of the construction period and cost when used in water depth and silt area, which provides useful experience for the silt coastal projects.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88899263","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 : 2022-10-30DOI: 10.14311/cej.2022.03.0031
Chiraz Kechkar, Leila Kherraf, Assia Abdelouahid, H. Hebhoub
The main objective of this study of research is to initiate and develop a comparative study of fresh and hardened properties of concretes made from recycled sand from three types of waste: marble waste, tiling waste and cinder block waste. And this, in the intention of contributing to the world effort relating to the preserve of natural aggregate resources and limit landfill to the ultimate waste thresholds. To do this, in the composition of a current concrete with a water / cement ratio equal to 0.55, an equivalent volume of sand from the three wastes respectively replaced a volume of 15% of the ordinary sand. The properties in the fresh state: workability, air content and density and in the hardened state: compressive strength, Flexural tensile strength, compressive strength determined with non-destructive tests, water absorption by immersion, absorption by capillarity and chloride penetration of the various concretes produced are analyzed, and compared to those of the control concrete. The results obtained show that the concretes containing the waste sands have acceptable characteristics. However, tiling waste sand performs better than the other two recycled sands.
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