Nowadays, excavation in urban environments can have many risks; one of these hazards is improper tail-grouting of Earth Pressure Balance Machine (EPBM) and the consequent ground surface settlement. Failure to fill the tail space with suitable grout significantly affects the surface displacements. Injecting more grout to penetrate deeper around the tunnel will play a more effective role in reducing displacements and permeability of the soil. Therefore, experimentally investigation of the feasibility of increasing the tail-grouting zone during excavation around the tunnel space and the effect of this penetration on the amount of ground surface displacements is the main purpose of this paper. Thus, experimental tests were performed with different grout injection pressure and the effect of each of the pressure on the penetration depth of grout into the soil new laboratory model were examined. Then to study the effect of the grout penetration depth on surface settlement to determination of the adequate amount of grout injection pressure a numerical modeling of Tabriz metro line 2 by FLAC3D software were completed. For this purpose, the results of the laboratory tests (the penetration depth of grout) were used in numerical modeling. The results indicated that the amount of penetration in the implemented granulation has increased due to the increase in pressure, so doubling the pressure causes a 30% increase in grout penetration in the surrounding soil. The results of numerical studies showed that increasing the range of injection in the modeling causes a significant reduction (80 percent) in the ground surface settlement.
{"title":"Investigation of the Feasibility of Increasing the Tail-grouting Zone during Mechanized Tunneling in Sandy Soils","authors":"Faezeh Barri, Hamid Chakeri, Hamed Haghkish, Milad Manafi","doi":"10.3311/ppci.23309","DOIUrl":"https://doi.org/10.3311/ppci.23309","url":null,"abstract":"Nowadays, excavation in urban environments can have many risks; one of these hazards is improper tail-grouting of Earth Pressure Balance Machine (EPBM) and the consequent ground surface settlement. Failure to fill the tail space with suitable grout significantly affects the surface displacements. Injecting more grout to penetrate deeper around the tunnel will play a more effective role in reducing displacements and permeability of the soil. Therefore, experimentally investigation of the feasibility of increasing the tail-grouting zone during excavation around the tunnel space and the effect of this penetration on the amount of ground surface displacements is the main purpose of this paper. Thus, experimental tests were performed with different grout injection pressure and the effect of each of the pressure on the penetration depth of grout into the soil new laboratory model were examined. Then to study the effect of the grout penetration depth on surface settlement to determination of the adequate amount of grout injection pressure a numerical modeling of Tabriz metro line 2 by FLAC3D software were completed. For this purpose, the results of the laboratory tests (the penetration depth of grout) were used in numerical modeling. The results indicated that the amount of penetration in the implemented granulation has increased due to the increase in pressure, so doubling the pressure causes a 30% increase in grout penetration in the surrounding soil. The results of numerical studies showed that increasing the range of injection in the modeling causes a significant reduction (80 percent) in the ground surface settlement.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmad Haydar Awrahman, Necip Altay Eren, Abdulkadir Çevik, Azad Abdulkadir Mohammed
This study primary is to investigate the shear strength of self-compacting concrete (SCC) reinforced by steel-fiber (SF) and polypropylene-fiber (PPF) in different environmental conditions: the air, sulfate (MgSO4 with a concentration of 5%) and acid (H2SO4 with a concentration of 5%). The study also examines the effect of fiber volume fraction on the workability, shear strength, compressive strength, and splitting tensile strength of fiber reinforced SCC. The article aims to determine the durability effects of both fibers and their resistance to aggressive environmental conditions. The contribution of this article is an experimental investigation on the shear strength of SCC reinforced by SF as well as PPF in 3 different environmental conditions after 30 days of exposure. The study also investigated the fresh and mechanical properties of 5 different mixtures of SCC with/out 0.1% and 0.2% fibers. The study also concluded that PPF decreased the workability of SCC badly, and special care must be taken when selecting its volume fraction. Also, it was found that generally shear strength of SCC mixes enhanced with increasing SF and PPF volume fraction. Moreover, it was found that both fibers have good durability effects, and resist aggressive environmental conditions, with the best results obtained from samples containing 0.2% SF. In the air condition, while the compressive strength, shear strength and tensile strength results were 52.6MPa, 6.43MPa and 3.91MPa, in the sulfate condition those were 46.37MPa, 6.55MPa and 3.59MPa, and in the acid condition those were 34.4MPa, 5.5MPa and 3.46MPa, respectively.
{"title":"Experimental Study on Direct Shear Strength of Fiber Reinforced Self Compacting Concrete under Acid and Sulfate Attack","authors":"Ahmad Haydar Awrahman, Necip Altay Eren, Abdulkadir Çevik, Azad Abdulkadir Mohammed","doi":"10.3311/ppci.22519","DOIUrl":"https://doi.org/10.3311/ppci.22519","url":null,"abstract":"This study primary is to investigate the shear strength of self-compacting concrete (SCC) reinforced by steel-fiber (SF) and polypropylene-fiber (PPF) in different environmental conditions: the air, sulfate (MgSO4 with a concentration of 5%) and acid (H2SO4 with a concentration of 5%). The study also examines the effect of fiber volume fraction on the workability, shear strength, compressive strength, and splitting tensile strength of fiber reinforced SCC. The article aims to determine the durability effects of both fibers and their resistance to aggressive environmental conditions. The contribution of this article is an experimental investigation on the shear strength of SCC reinforced by SF as well as PPF in 3 different environmental conditions after 30 days of exposure. The study also investigated the fresh and mechanical properties of 5 different mixtures of SCC with/out 0.1% and 0.2% fibers. The study also concluded that PPF decreased the workability of SCC badly, and special care must be taken when selecting its volume fraction. Also, it was found that generally shear strength of SCC mixes enhanced with increasing SF and PPF volume fraction. Moreover, it was found that both fibers have good durability effects, and resist aggressive environmental conditions, with the best results obtained from samples containing 0.2% SF. In the air condition, while the compressive strength, shear strength and tensile strength results were 52.6MPa, 6.43MPa and 3.91MPa, in the sulfate condition those were 46.37MPa, 6.55MPa and 3.59MPa, and in the acid condition those were 34.4MPa, 5.5MPa and 3.46MPa, respectively.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135678867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aggregates are essential materials in civil engineering, they are used for railway and road constructions, for hydraulic engineering but they are also the base material of concrete. The crushed stones are exposed to several effects during their lifespan. Therefore, several tests were developed to evaluate their performance. One of the most important aspects is the resistance to degradation. However, degradation tests require special types of equipment and usually take longer than common strength tests which are more likely to be available for rock materials. Therefore, the empirical connections between strength and degradation values can be extremely useful in practice. The paper aimed to collect all available relationships and datasets from the literature that presents the relations between these different parameters – such as Aggregate Impact Value (AIV), Aggregate Crushing Value (ACV), Ten Percent Fines Value (TFV), Los Angeles Abrasion Value (LAAV), and micro-Deval Coefficient (MDE) – and rock strength parameters – such as Uniaxial Compressive Strength (UCS) and Point Load Strength Index (IS(50)) – and to provide the best-fit formula for different rock types. The paper also highlights the difficulties and limitations of the compared relationships.
{"title":"Overview of the Empirical Relations between Different Aggregate Degradation Values and Rock Strength Parameters","authors":"Eszter Kuna, Gyula Bögöly","doi":"10.3311/ppci.22396","DOIUrl":"https://doi.org/10.3311/ppci.22396","url":null,"abstract":"The aggregates are essential materials in civil engineering, they are used for railway and road constructions, for hydraulic engineering but they are also the base material of concrete. The crushed stones are exposed to several effects during their lifespan. Therefore, several tests were developed to evaluate their performance. One of the most important aspects is the resistance to degradation. However, degradation tests require special types of equipment and usually take longer than common strength tests which are more likely to be available for rock materials. Therefore, the empirical connections between strength and degradation values can be extremely useful in practice. The paper aimed to collect all available relationships and datasets from the literature that presents the relations between these different parameters – such as Aggregate Impact Value (AIV), Aggregate Crushing Value (ACV), Ten Percent Fines Value (TFV), Los Angeles Abrasion Value (LAAV), and micro-Deval Coefficient (MDE) – and rock strength parameters – such as Uniaxial Compressive Strength (UCS) and Point Load Strength Index (IS(50)) – and to provide the best-fit formula for different rock types. The paper also highlights the difficulties and limitations of the compared relationships.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yielding dampers are often selected as a cost-effective solution for improving steel structures compared to other energy dissipation systems. The objective of this research study was to investigate the cyclic behavior of the angled U-shaped yielding damper (AUSYD) on a steel frame using numerical method. The numerical model was first verified using two experimental samples. Next, the influence of the number of dampers on the cyclic behavior of the steel frame was examined. The parametric model outcomes included energy dissipation, elastic stiffness, strength, and equivalent viscous damping ratio (EVDR). Additionally, an analytical equation was proposed for calculating the ultimate strength of the AUSYD, which correlated well with the experimentally obtained results. The study findings revealed that the increase in elastic stiffness and strength of the frame equipped with the AUSYD was nearly equivalent to the sum of the elastic stiffness and strength of the bare frame and its supplementary dampers. Furthermore, the results showed that models with 8 to 12 dampers had comparable energy dissipation and EVDR. Adding 8 dampers to the frame increased the energy dissipation and damping coefficient of the frame by 42% and 67%, respectively.
{"title":"Numerical Investigation of Cyclic Behavior of Angled U-shaped Yielding Damper on Steel Frames","authors":"Kambiz Cheraghi, Mehrzad TahamouliRoudsari, Sasan Kiasat, Javad Esfandiari","doi":"10.3311/ppci.23213","DOIUrl":"https://doi.org/10.3311/ppci.23213","url":null,"abstract":"Yielding dampers are often selected as a cost-effective solution for improving steel structures compared to other energy dissipation systems. The objective of this research study was to investigate the cyclic behavior of the angled U-shaped yielding damper (AUSYD) on a steel frame using numerical method. The numerical model was first verified using two experimental samples. Next, the influence of the number of dampers on the cyclic behavior of the steel frame was examined. The parametric model outcomes included energy dissipation, elastic stiffness, strength, and equivalent viscous damping ratio (EVDR). Additionally, an analytical equation was proposed for calculating the ultimate strength of the AUSYD, which correlated well with the experimentally obtained results. The study findings revealed that the increase in elastic stiffness and strength of the frame equipped with the AUSYD was nearly equivalent to the sum of the elastic stiffness and strength of the bare frame and its supplementary dampers. Furthermore, the results showed that models with 8 to 12 dampers had comparable energy dissipation and EVDR. Adding 8 dampers to the frame increased the energy dissipation and damping coefficient of the frame by 42% and 67%, respectively.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amir Meysam Giahi, Jafar Asgari Marnani, Mohammad Sadegh Rohanimanesh, Hassan Ahmadi
Determining the optimal location of sensors in order to identify modal parameters in large structures such as dams is one of the most important and widely used topics in damage detection and health monitoring of structures. In this research, the modal parameters including the natural frequency and mode shape of two arched concrete dams have been calculated using the finite element method for healthy and damaged dams. The reduction of the elastic modulus of concrete in different parts and percentages has been used as the degree of damage. Then, using the modal confidence criterion (MAC) method, the optimal location of the sensors is determined, then the results of this method are compared with the new method. The results show that in both dams, the new method matches the MAC method with 90% accuracy. This new method is a fast and suitable measure to determine the optimal location of sensors in arched concrete dams.
{"title":"A New Optimal Sensor Location Method for Double-curvature Arch Dams: A Comparison with the Modal Assurance Criterion (MAC)","authors":"Amir Meysam Giahi, Jafar Asgari Marnani, Mohammad Sadegh Rohanimanesh, Hassan Ahmadi","doi":"10.3311/ppci.22031","DOIUrl":"https://doi.org/10.3311/ppci.22031","url":null,"abstract":"Determining the optimal location of sensors in order to identify modal parameters in large structures such as dams is one of the most important and widely used topics in damage detection and health monitoring of structures. In this research, the modal parameters including the natural frequency and mode shape of two arched concrete dams have been calculated using the finite element method for healthy and damaged dams. The reduction of the elastic modulus of concrete in different parts and percentages has been used as the degree of damage. Then, using the modal confidence criterion (MAC) method, the optimal location of the sensors is determined, then the results of this method are compared with the new method. The results show that in both dams, the new method matches the MAC method with 90% accuracy. This new method is a fast and suitable measure to determine the optimal location of sensors in arched concrete dams.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135634106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Local soil conditions play a significant role in the intensity variations of seismic waves during earthquakes. These variations can be either amplified or de-amplified depending on the specific soil conditions. This study aimed to assess the impact of different soil profiles on seismic site responses. The study considered four types of site profiles: sand (Sa), clay (Cl), sand overlying clay (SaCl), and clay overlying sand (ClSa) profiles. To simulate the ground motion, we selected seven sets of strong earthquake records from the European Strong-Motion Database. These records were selected according to Eurocode-8 with a peak ground acceleration (PGA) of 0.24 g, site class A using REXEL computer program. The records were then applied to the bedrock at a depth of 30 meters. Subsequently, a series of 1-D equivalent linear (EQL) response analyses were performed using the STRATA. Amplification factors (AFs) and surface acceleration time histories provided quantitative evaluations for our analysis results. The results demonstrated that site profiles with clay overlying bedrock (SaCl and Cl profiles) exhibited higher seismic amplification and peak ground acceleration in comparison to site profiles with sand overlying bedrock (Sa and ClSa profiles). The maximum median AF is calculated from the SaCl site profile, while the minimum median AF was calculated from the ClSa profile. The relative difference between the maximum and the minimum median AFs was about 33.7%. Based on these results, we can conclude that soft local soils have a pronounced effect on the amplification of seismic waves compared to stiff local soils.
{"title":"Effects of Local Soil Profiles on Seismic Site Response Analysis","authors":"Ayele Chala, Richard Ray","doi":"10.3311/ppci.22148","DOIUrl":"https://doi.org/10.3311/ppci.22148","url":null,"abstract":"Local soil conditions play a significant role in the intensity variations of seismic waves during earthquakes. These variations can be either amplified or de-amplified depending on the specific soil conditions. This study aimed to assess the impact of different soil profiles on seismic site responses. The study considered four types of site profiles: sand (Sa), clay (Cl), sand overlying clay (SaCl), and clay overlying sand (ClSa) profiles. To simulate the ground motion, we selected seven sets of strong earthquake records from the European Strong-Motion Database. These records were selected according to Eurocode-8 with a peak ground acceleration (PGA) of 0.24 g, site class A using REXEL computer program. The records were then applied to the bedrock at a depth of 30 meters. Subsequently, a series of 1-D equivalent linear (EQL) response analyses were performed using the STRATA. Amplification factors (AFs) and surface acceleration time histories provided quantitative evaluations for our analysis results. The results demonstrated that site profiles with clay overlying bedrock (SaCl and Cl profiles) exhibited higher seismic amplification and peak ground acceleration in comparison to site profiles with sand overlying bedrock (Sa and ClSa profiles). The maximum median AF is calculated from the SaCl site profile, while the minimum median AF was calculated from the ClSa profile. The relative difference between the maximum and the minimum median AFs was about 33.7%. Based on these results, we can conclude that soft local soils have a pronounced effect on the amplification of seismic waves compared to stiff local soils.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amirhesam Taghipour, Jabbar Ali Zakeri, Seyed Ali Mosayebi
Nowadays, attention to railways has been increased as one of the important transportation methods. Various factors can cause longitudinal forces on the railway tracks, so the most important factors are the temperature changes due to the rail contraction and expansion (thermal forces), train braking system forces and acceleration, etc. Increasing longitudinal force can lead to buckling phenomena in railway tracks. In this paper, the effects of tensile and compressive longitudinal forces on the parameters of rail, sleeper, and ballast layers under vertical moving loads are investigated by using the finite element method. In this regard, by performing sensitivity analyses for different values of longitudinal forces and train speeds dynamic responses (displacement, velocity, and acceleration) of railway track components like rail, sleeper, and ballast have been studied. The results show that increasing the values of longitudinal axial force from –2000 [kN] up to 2000 [kN] as well as increasing the train speed from 10 [m/s] (36 [km/h]) up to 100 [m/s] (360 [km/h]) increases the rail displacement and velocity in the range of 25% up to 37% also the rail acceleration in the range of 9% up to 14%. The velocity and acceleration of the sleeper also the ballast velocity increase in the range of 24% up to 30% and 7% up to 9%, respectively, by increasing the speed of the train from 10 [m/s] (36 [km/h]) to 100 [m/s] (360 [km/h]) in all three modes without applying axial force, considering compressive and tensile one in the train-track interaction system.
{"title":"Investigations on the Effects of Rail Longitudinal Forces in Train-Track Dynamic Interaction","authors":"Amirhesam Taghipour, Jabbar Ali Zakeri, Seyed Ali Mosayebi","doi":"10.3311/ppci.22964","DOIUrl":"https://doi.org/10.3311/ppci.22964","url":null,"abstract":"Nowadays, attention to railways has been increased as one of the important transportation methods. Various factors can cause longitudinal forces on the railway tracks, so the most important factors are the temperature changes due to the rail contraction and expansion (thermal forces), train braking system forces and acceleration, etc. Increasing longitudinal force can lead to buckling phenomena in railway tracks. In this paper, the effects of tensile and compressive longitudinal forces on the parameters of rail, sleeper, and ballast layers under vertical moving loads are investigated by using the finite element method. In this regard, by performing sensitivity analyses for different values of longitudinal forces and train speeds dynamic responses (displacement, velocity, and acceleration) of railway track components like rail, sleeper, and ballast have been studied. The results show that increasing the values of longitudinal axial force from –2000 [kN] up to 2000 [kN] as well as increasing the train speed from 10 [m/s] (36 [km/h]) up to 100 [m/s] (360 [km/h]) increases the rail displacement and velocity in the range of 25% up to 37% also the rail acceleration in the range of 9% up to 14%. The velocity and acceleration of the sleeper also the ballast velocity increase in the range of 24% up to 30% and 7% up to 9%, respectively, by increasing the speed of the train from 10 [m/s] (36 [km/h]) to 100 [m/s] (360 [km/h]) in all three modes without applying axial force, considering compressive and tensile one in the train-track interaction system.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134909335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sándor Szalai, Péter Szűcs, István Lemperger, Mohamed Zubair, Mohamed Metwaly, Katalin Gribovszki, Krisztián Baracza
Pressure Probe (PreP) is in effect a simplified penetrometer: it measures the mechanical resistivity of the soil at shallow depths dropping the probe always from the same height. The resolution of this technique is very good. It is able to detect e.g., fractures due to their decreased mechanical resistance if they are covered, but in a shallow depth with a reasonable sampling distance. An example will be demonstrated where fracture system of a slowly-moving landslide was characterized enabling also its delineation. In spite of that its maximal penetration is only about 0.5 m it may also give information from remarkable depths in case if fractures reach close to the surface indicating the borders of geological structures in larger depth. An example from India will be shown to present such results. All results have been verified by geoelectric measurements. PreP may also indicate any kind of hidden holes indirectly.
{"title":"Fracture system characterization by Pressure Probe","authors":"Sándor Szalai, Péter Szűcs, István Lemperger, Mohamed Zubair, Mohamed Metwaly, Katalin Gribovszki, Krisztián Baracza","doi":"10.3311/ppci.19916","DOIUrl":"https://doi.org/10.3311/ppci.19916","url":null,"abstract":"Pressure Probe (PreP) is in effect a simplified penetrometer: it measures the mechanical resistivity of the soil at shallow depths dropping the probe always from the same height. The resolution of this technique is very good. It is able to detect e.g., fractures due to their decreased mechanical resistance if they are covered, but in a shallow depth with a reasonable sampling distance. An example will be demonstrated where fracture system of a slowly-moving landslide was characterized enabling also its delineation. In spite of that its maximal penetration is only about 0.5 m it may also give information from remarkable depths in case if fractures reach close to the surface indicating the borders of geological structures in larger depth. An example from India will be shown to present such results. All results have been verified by geoelectric measurements. PreP may also indicate any kind of hidden holes indirectly.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134910249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hamidreza Aghani, Kambiz Cheraghi, Mohammad Bakhshipour
During an earthquake, yielding dampers yield before the main members of the structure and with their plastic deformations, they dissipate part of the earthquake energy. Therefore, ductile materials are a suitable option for this type of dampers. In this research, numerical studies were conducted to investigate the effect of aluminum yielding damper (AYD) on semi-rigid steel frame. First, the steel frame and the AYD were verified based on experimental samples and analytical equations. An approximate equation for estimating the elastic stiffness of the damper was also presented. Parametric studies were conducted in order to investigate the effect of the number of dampers and the axial force of the column on the stiffness, ultimate strength, ductility and energy dissipation parameters of the frame. The additional forces applied to the connections, beams and columns of the frame due to the addition of dampers were also calculated, which is important in the design of the frame. The results showed that the addition of the damper increased the frame's stiffness, energy dissipation, ultimate strength, and ductility, and also reduced the negative effect of the column's axial force on energy dissipation of the frame.
{"title":"Numerical Investigation of the Effect of Aluminum Yielding Damper for the Retrofitting of Semi-rigid Steel Frames","authors":"Hamidreza Aghani, Kambiz Cheraghi, Mohammad Bakhshipour","doi":"10.3311/ppci.23119","DOIUrl":"https://doi.org/10.3311/ppci.23119","url":null,"abstract":"During an earthquake, yielding dampers yield before the main members of the structure and with their plastic deformations, they dissipate part of the earthquake energy. Therefore, ductile materials are a suitable option for this type of dampers. In this research, numerical studies were conducted to investigate the effect of aluminum yielding damper (AYD) on semi-rigid steel frame. First, the steel frame and the AYD were verified based on experimental samples and analytical equations. An approximate equation for estimating the elastic stiffness of the damper was also presented. Parametric studies were conducted in order to investigate the effect of the number of dampers and the axial force of the column on the stiffness, ultimate strength, ductility and energy dissipation parameters of the frame. The additional forces applied to the connections, beams and columns of the frame due to the addition of dampers were also calculated, which is important in the design of the frame. The results showed that the addition of the damper increased the frame's stiffness, energy dissipation, ultimate strength, and ductility, and also reduced the negative effect of the column's axial force on energy dissipation of the frame.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135779314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seyedeh Maryam Dashti Zand, Vahidreza Kalatjari, Nader K. A. Attari
Unstiffened steel plate shear walls have low buckling strength, which caused development diagonal tension field under lateral load. Corrugated plates have higher out-of-plane stiffness and improved buckling stability. Combining corrugated and flat plates in steel shear wall web could be effective. In this paper a new steel shear wall system reinforced with trapezoidal corrugated steel plates were proposed. In this study, the behavior of the system was experimentally studied under cyclic loading. Four specimens with the one-third scale were evaluated, which were control unstiffened specimen, the specimen with vertical 45° trapezoidal corrugated web, specimen with a corrugated web plate reinforced with two flat plates, and specimen with a flat web plate reinforced with two corrugated plates. In all four specimens, the total thicknesses of steel plates were the same; therefore, the thickness of each plate in specimens with three plates was one-third of the specimen with one plate. The studied parameters were the bearing capacity, maximum base shear, stiffness, ductility, energy absorption, and modification factor for the dissipation capacity of the specimens. The results revealed the maximum lateral load capacity of specimen with a flat web plate reinforced with two corrugated plates increased about 17%, 37%, and 19%, comparly to unstiffened specimens, vertical 45° trapezoidal corrugated web, and corrugated web plate reinforced with two flat plates, respectively. According to the results, the behavior of the seismic parameters of the proposed specimen with a flat web plate reinforced with two corrugated plates was clearly better than that of the other specimens.
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