Using concrete for filling and bracing is one of the most crucial ways to improve cold-formed steel (CFS) elements' stability behavior and performance. An example is the novel building system made up by CFS encased in ultra-lightweight concrete. The numerical analysis of such structural members using solid finite elements is time-consuming, thus the need for an easy-to-use modelling technique has arisen. As a result, a simple time-efficient equivalent spring model (ESM) has been introduced as a viable method for properly analyzing complex structural behavior in numerous cases, replacing the concrete solid with one-directional springs applying the Winkler foundation. This study aims to examine the validity and limitations of the ESM by comparing it to 3D solid model (SMOD) results for internal plate elements. The analysis results indicate that the ESM could provide accurate results in the b/t range of 100 or less for a wide range of PAC modulus (50–250 MPa) with an error of less than 5%; hence, using spring in modelling PAC within these limits is deemed acceptable. Nevertheless, for larger b/t values up to 175, doubled the calculated spring stiffness is highly recommended. In addition, the results reveal that the applicability of ESM is limited for b/t above 175; the model fails to predict the ultimate failure load, and the failure mode. Finally, this study ends by recommending one equation for calculating equivalent foundation spring stiffness for internal components that ensure optimal performance of the ESM analysis.
{"title":"Assessing the Equivalent Spring Method for Modelling of Lightweight-concrete Encased Cold-formed Steel Elements in Compression","authors":"Ahmed Alabedi, Péter Hegyi","doi":"10.3311/ppci.22803","DOIUrl":"https://doi.org/10.3311/ppci.22803","url":null,"abstract":"Using concrete for filling and bracing is one of the most crucial ways to improve cold-formed steel (CFS) elements' stability behavior and performance. An example is the novel building system made up by CFS encased in ultra-lightweight concrete. The numerical analysis of such structural members using solid finite elements is time-consuming, thus the need for an easy-to-use modelling technique has arisen. As a result, a simple time-efficient equivalent spring model (ESM) has been introduced as a viable method for properly analyzing complex structural behavior in numerous cases, replacing the concrete solid with one-directional springs applying the Winkler foundation. This study aims to examine the validity and limitations of the ESM by comparing it to 3D solid model (SMOD) results for internal plate elements. The analysis results indicate that the ESM could provide accurate results in the b/t range of 100 or less for a wide range of PAC modulus (50–250 MPa) with an error of less than 5%; hence, using spring in modelling PAC within these limits is deemed acceptable. Nevertheless, for larger b/t values up to 175, doubled the calculated spring stiffness is highly recommended. In addition, the results reveal that the applicability of ESM is limited for b/t above 175; the model fails to predict the ultimate failure load, and the failure mode. Finally, this study ends by recommending one equation for calculating equivalent foundation spring stiffness for internal components that ensure optimal performance of the ESM analysis.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136114063","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 use of lateral bearing systems to rehabilitate reinforced concrete frames has been one of the most important research topics in structural engineering. Non-uniform Slit Dampers (NSD), as well as Bar dampers, are two types of novel yielding dampers whose effects on reinforced concrete structures have been evaluated in this research. In this research, three experimental samples with a one-third scale were constructed to assess the effect of the presence of NSD and Bar damper in reinforced concrete frames. Also, 16 numerical models were created to evaluate the number of used dampers in experimental specimens in order to determine the optimal mode of using these dampers. Seismic parameters of stiffness, ultimate strength, ductility, and energy dissipation capacity were investigated in this research. The research results showed that the use of lateral bearing systems with NSD and bar dampers can have a significant impact on the seismic performance of reinforced concrete moment resisting frames. Also, in the numerical models that were made using ABAQUS software, it was concluded that the use of a smaller number of dampers compared to the experimental models can still improve the seismic parameters of the system while the cyclic capacity of the system does not drop.
{"title":"Experimental and Numerical Assessment of the Seismic Behavior of Non-uniform Slit Dampers and Bar Dampers in Moment Resisting Reinforced Concrete Frames","authors":"Hemat Rahimi, Javad Esfandari, Mehrzad TahamouliRoudsari","doi":"10.3311/ppci.22993","DOIUrl":"https://doi.org/10.3311/ppci.22993","url":null,"abstract":"The use of lateral bearing systems to rehabilitate reinforced concrete frames has been one of the most important research topics in structural engineering. Non-uniform Slit Dampers (NSD), as well as Bar dampers, are two types of novel yielding dampers whose effects on reinforced concrete structures have been evaluated in this research. In this research, three experimental samples with a one-third scale were constructed to assess the effect of the presence of NSD and Bar damper in reinforced concrete frames. Also, 16 numerical models were created to evaluate the number of used dampers in experimental specimens in order to determine the optimal mode of using these dampers. Seismic parameters of stiffness, ultimate strength, ductility, and energy dissipation capacity were investigated in this research. The research results showed that the use of lateral bearing systems with NSD and bar dampers can have a significant impact on the seismic performance of reinforced concrete moment resisting frames. Also, in the numerical models that were made using ABAQUS software, it was concluded that the use of a smaller number of dampers compared to the experimental models can still improve the seismic parameters of the system while the cyclic capacity of the system does not drop.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112923","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}
Biological filtration is a complex process consisting of two consecutive stages. The nutrient transport stage, which is influenced by various fluid mechanical and surface-physical factors, represents a precondition for the biochemical process taking place within the biofilm. Biological water filtration is based on the catalyzed decomposition of contaminant molecules with the help of enzymes. This article, in addition to describing the conditions and mode of action typical within this second stage, also aims to explore the practical implications of the established results, including the controllability of biological reactors.
{"title":"Processes Occurring within the Biofilm","authors":"Béla Tolnai","doi":"10.3311/ppci.22685","DOIUrl":"https://doi.org/10.3311/ppci.22685","url":null,"abstract":"Biological filtration is a complex process consisting of two consecutive stages. The nutrient transport stage, which is influenced by various fluid mechanical and surface-physical factors, represents a precondition for the biochemical process taking place within the biofilm. Biological water filtration is based on the catalyzed decomposition of contaminant molecules with the help of enzymes. This article, in addition to describing the conditions and mode of action typical within this second stage, also aims to explore the practical implications of the established results, including the controllability of biological reactors.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136113084","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}
In structural construction practice, the use of reinforced concrete slabs is extremely common due to their structural and economic advantages. An important issue is the study of structural behavior given to horizontal effects. The significance of this is centered not only on the scales caused by wind and construction loads, which are considered to be “normal” i.e., the quasi-static, which is essentially one-way monotonically increasing but also the most researched seismic, i.e., cyclically varying, direction and magnitude effects. The most widespread methods for sizing flat plate slabs to unidirectional, quasi-static horizontal loads are the so-called Equivalent Frame Method and the Effective Beam Width Method. In addition to analytical and basically linear numerical theoretical methods, several laboratory experiments have been performed and published. In this paper, we investigate the behavior of column-supported flat plate slabs against unidirectional, monotonically increasing horizontal loads using an advanced nonlinear numerical modeling method. Numerical models constructed with different geometric dimensions were created with ATENA 3D three-dimensional nonlinear finite element software. In the numerical studies, in addition to the vertical loads in the global sense, the horizontal loads were also taken into account. In our studies, we analyzed the global behavior of the structure, crack propagation, and internal stresses. The results were illustrated on force - displacement diagrams and compared with the results of the laboratory experiments used, thus showing the accuracy and limitations of the numerical modeling procedure. The numerical results were also compared with the results determined on the basis of the equivalent framework models.
{"title":"Finite Element Analyses of Cast-in-situ RC Flat Slab with an Equivalent Frame for Horizontal Loads","authors":"Zsolt Roszevák, István Haris","doi":"10.3311/ppci.21896","DOIUrl":"https://doi.org/10.3311/ppci.21896","url":null,"abstract":"In structural construction practice, the use of reinforced concrete slabs is extremely common due to their structural and economic advantages. An important issue is the study of structural behavior given to horizontal effects. The significance of this is centered not only on the scales caused by wind and construction loads, which are considered to be “normal” i.e., the quasi-static, which is essentially one-way monotonically increasing but also the most researched seismic, i.e., cyclically varying, direction and magnitude effects. The most widespread methods for sizing flat plate slabs to unidirectional, quasi-static horizontal loads are the so-called Equivalent Frame Method and the Effective Beam Width Method. In addition to analytical and basically linear numerical theoretical methods, several laboratory experiments have been performed and published. In this paper, we investigate the behavior of column-supported flat plate slabs against unidirectional, monotonically increasing horizontal loads using an advanced nonlinear numerical modeling method. Numerical models constructed with different geometric dimensions were created with ATENA 3D three-dimensional nonlinear finite element software. In the numerical studies, in addition to the vertical loads in the global sense, the horizontal loads were also taken into account. In our studies, we analyzed the global behavior of the structure, crack propagation, and internal stresses. The results were illustrated on force - displacement diagrams and compared with the results of the laboratory experiments used, thus showing the accuracy and limitations of the numerical modeling procedure. The numerical results were also compared with the results determined on the basis of the equivalent framework models.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136352580","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}
Eray Yıldırım, Ertan Bol, Eyübhan Avcı, Aşkın Özocak
This study investigates the stabilization performance of clayey soil treated with alkali-activated hybrid slag/cement. Sodium silicate (SS) and sodium hydroxide (SH) are used as alkali activators, whereas ground blast furnace slag (GGBS) and ordinary Portland cement (OPC) are used as sources of aluminosilicate. A total of 27 different types of mixtures are used for stabilization. Unconfined compressive strength (UCS) of untreated clay and stabilized soils are performed at immediately, 3-, 7-, 28-, and 90 days curing times under air-dried and wet-cured conditions. In addition, 90-d volume and mass changes in the samples are measured. Stabilized samples with an SS/SH ratio of 1 under air-dried conditions reveal moistening at early curing ages (≤28 days); afterward, sodium carbonate crystals appear in these samples at longer curing ages. Geopolymer-treated clayey soil exhibits lower volumetric and mass changes compared with OPC. Most of the stabilized clayey soil with alkali-activated hybrid slag/cement exhibits higher strength compared with OPC under air-dried and wet-cured conditions.
{"title":"Stabilization of Clayey Soil with Alkali-activated Hybrid Slag/Cement","authors":"Eray Yıldırım, Ertan Bol, Eyübhan Avcı, Aşkın Özocak","doi":"10.3311/ppci.21964","DOIUrl":"https://doi.org/10.3311/ppci.21964","url":null,"abstract":"This study investigates the stabilization performance of clayey soil treated with alkali-activated hybrid slag/cement. Sodium silicate (SS) and sodium hydroxide (SH) are used as alkali activators, whereas ground blast furnace slag (GGBS) and ordinary Portland cement (OPC) are used as sources of aluminosilicate. A total of 27 different types of mixtures are used for stabilization. Unconfined compressive strength (UCS) of untreated clay and stabilized soils are performed at immediately, 3-, 7-, 28-, and 90 days curing times under air-dried and wet-cured conditions. In addition, 90-d volume and mass changes in the samples are measured. Stabilized samples with an SS/SH ratio of 1 under air-dried conditions reveal moistening at early curing ages (≤28 days); afterward, sodium carbonate crystals appear in these samples at longer curing ages. Geopolymer-treated clayey soil exhibits lower volumetric and mass changes compared with OPC. Most of the stabilized clayey soil with alkali-activated hybrid slag/cement exhibits higher strength compared with OPC under air-dried and wet-cured conditions.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135592358","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}
As a result of the rapid increase in the demand for transportation vehicles recently, the accumulation of waste tires causes environmental problems. One of the methods that can contribute to the reduction of this environmental problem is the recycling of waste tires as a construction material in aggregate form. This research investigated the impacts of waste tire crumb rubber with/out steel fiber (SF) on the two-way punching-shear behavior alkali-activated concrete (AAC) flat slabs and performed center point load tests. In the study, one-type of SF and two kinds of scrap tire waste i.e., crumb rubber (CR) and tire particles, were used on the producing of rubberized AAC slabs obtained by 100% as binder made of ground-granulated blast furnace slag (GGBFS). Also, while both fine crumb rubber (FCR) and coarse crumb rubber (CCR) were used together in the AAC slabs, tire crumb rubber (TCR) was used alone at the same proportion. Additionally, the fine aggregate was substituted with 10% and 15% FCR and CCR, and coarse aggregate was substituted with TCR in the same proportions. Additionally, AAC slabs with recycled tire rubber (RTR) were produced as fibrous and non-fibrous using 1% by volume hook-end SF. In total, nine AAC slabs with sizes of 50 x 50 x 6 cm3 were manufactured for the study. Experimental data showed that the inclusion of RTR only slightly reduced the punching shear strength of AAC slabs and the punching shear strength of the slabs increased when SF was added to the mixtures containing RTR.
近年来，由于交通运输车辆需求量的迅速增加，废旧轮胎的堆积造成了环境问题。其中一个方法，可以有助于减少这种环境问题是回收废旧轮胎作为建筑材料的骨料形式。研究了废轮胎橡胶渣掺/脱钢纤维(SF)对碱活化混凝土平板双向冲剪性能的影响，并进行了中心点荷载试验。本研究以1种硫化橡胶和2种废轮胎废料，即橡胶屑(CR)和轮胎颗粒，作为磨粒高炉渣(GGBFS)的粘结剂，用于生产100%的硫化AAC板。细粒橡胶(FCR)和粗粒橡胶(CCR)在AAC板中同时使用，轮胎橡胶(TCR)按相同比例单独使用。细骨料分别用10%和15%的FCR和CCR替代，粗骨料用相同比例的TCR替代。此外，AAC板与再生轮胎橡胶(RTR)生产纤维和非纤维使用1%的体积钩端SF。总共制造了9块AAC板，尺寸为50 x 50 x 6 cm3。实验数据表明，RTR的掺入对AAC板的冲切抗剪强度仅略有降低，而在含RTR的混合物中加入SF后，AAC板的冲切抗剪强度有所提高。
{"title":"Effects of Tire Crumb Rubber and Steel Fiber on Punching Shear Behavior of Two-way Alkali-activated Concrete Flat Slabs","authors":"Necip Altay Eren, Abdulkadir Çevik","doi":"10.3311/ppci.21990","DOIUrl":"https://doi.org/10.3311/ppci.21990","url":null,"abstract":"As a result of the rapid increase in the demand for transportation vehicles recently, the accumulation of waste tires causes environmental problems. One of the methods that can contribute to the reduction of this environmental problem is the recycling of waste tires as a construction material in aggregate form. This research investigated the impacts of waste tire crumb rubber with/out steel fiber (SF) on the two-way punching-shear behavior alkali-activated concrete (AAC) flat slabs and performed center point load tests. In the study, one-type of SF and two kinds of scrap tire waste i.e., crumb rubber (CR) and tire particles, were used on the producing of rubberized AAC slabs obtained by 100% as binder made of ground-granulated blast furnace slag (GGBFS). Also, while both fine crumb rubber (FCR) and coarse crumb rubber (CCR) were used together in the AAC slabs, tire crumb rubber (TCR) was used alone at the same proportion. Additionally, the fine aggregate was substituted with 10% and 15% FCR and CCR, and coarse aggregate was substituted with TCR in the same proportions. Additionally, AAC slabs with recycled tire rubber (RTR) were produced as fibrous and non-fibrous using 1% by volume hook-end SF. In total, nine AAC slabs with sizes of 50 x 50 x 6 cm3 were manufactured for the study. Experimental data showed that the inclusion of RTR only slightly reduced the punching shear strength of AAC slabs and the punching shear strength of the slabs increased when SF was added to the mixtures containing RTR.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591715","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}
Samad Narimani, Seyed Motreza Davarpanah, Balázs Vásárhelyi
The value of Poisson's ratio is a crucial parameter in rock mechanics and engineering for both intact rock and rock mass. Poisson's ratio has not gotten the attention it merits compared to other essential mechanical characteristics of intact rock and rock mass. Limited relationships exist between rock mass classification systems (such as RMR, RMQR, Q, and GSI) and Poisson's ratio. This paper provides a comprehensive review of models proposed by various researchers for estimating Poisson's ratio for rock mass. The different methods are compared, and new general equations are derived. The results indicate that the Poisson's ratio value of rock mass is inversely proportional to its quality and strength and depends on the Poisson's ratio value of the intact rock. Specifically, a linear equation is obtained using the RMR or GSI system, showing that the Poisson's ratio increases as the quality and strength of the rock mass decrease. The Q system has a logarithmic link between the rock mass quality and Poisson's ratio. It should be noted that the derived equations are applicable only under the assumption of a homogeneous isotropic rock mass.
{"title":"Estimation of the Poisson's Ratio of the Rock Mass","authors":"Samad Narimani, Seyed Motreza Davarpanah, Balázs Vásárhelyi","doi":"10.3311/ppci.22689","DOIUrl":"https://doi.org/10.3311/ppci.22689","url":null,"abstract":"The value of Poisson's ratio is a crucial parameter in rock mechanics and engineering for both intact rock and rock mass. Poisson's ratio has not gotten the attention it merits compared to other essential mechanical characteristics of intact rock and rock mass. Limited relationships exist between rock mass classification systems (such as RMR, RMQR, Q, and GSI) and Poisson's ratio. This paper provides a comprehensive review of models proposed by various researchers for estimating Poisson's ratio for rock mass. The different methods are compared, and new general equations are derived. The results indicate that the Poisson's ratio value of rock mass is inversely proportional to its quality and strength and depends on the Poisson's ratio value of the intact rock. Specifically, a linear equation is obtained using the RMR or GSI system, showing that the Poisson's ratio increases as the quality and strength of the rock mass decrease. The Q system has a logarithmic link between the rock mass quality and Poisson's ratio. It should be noted that the derived equations are applicable only under the assumption of a homogeneous isotropic rock mass.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135590685","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}
Studies show that design codes did not provide a reliable way to consider the effects of successive earthquakes on the behavior of the RC buildings. A lot of research are underway in this field, but the effect of shear wall placement in the regular and irregular structures under the seismic sequences and the imposing the vertical acceleration component to them has not been considered. For this purpose, in this study, the Christchurc earthquakes have been employed to observe the effects of seismic sequences on the location of the shear wall in the regular and irregular 3- and 8-story structures. The studied reinforced concrete structures have a dual system of flexural frames with shear walls. In this study, the designed shear wall with ACI code 318-14 is located in the different openings of structures. To model the frame of the structures of concrete flexural frame with wall, the Ibarra and Krawinkler concentrated joint behavioral model has been considered. The Hazus code is utilized to provide the fragility curves and also to indicate the failures based on the four drift-based performance levels. The IDA analysis is then performed on the models and the results are acquired. The failure index is considered as the maximum drift between the floors of the structures. The IR_3S_MO structure under main earthquakes at the three performance levels (Slight, Moderate, Complete) can withstand 11%, 14% and 88% spectral acceleration more than the IR_3S_LO structure, respectively. This ratio is approximately 10%, 12% and 42% for the IR_3S_RO structure, respectively.
{"title":"The Effects of Sequential Aftershocks on the Behavior of the Irregular RC Buildings","authors":"Farhad Hosseinlou, Mojtaba Labibzadeh","doi":"10.3311/ppci.20795","DOIUrl":"https://doi.org/10.3311/ppci.20795","url":null,"abstract":"Studies show that design codes did not provide a reliable way to consider the effects of successive earthquakes on the behavior of the RC buildings. A lot of research are underway in this field, but the effect of shear wall placement in the regular and irregular structures under the seismic sequences and the imposing the vertical acceleration component to them has not been considered. For this purpose, in this study, the Christchurc earthquakes have been employed to observe the effects of seismic sequences on the location of the shear wall in the regular and irregular 3- and 8-story structures. The studied reinforced concrete structures have a dual system of flexural frames with shear walls. In this study, the designed shear wall with ACI code 318-14 is located in the different openings of structures. To model the frame of the structures of concrete flexural frame with wall, the Ibarra and Krawinkler concentrated joint behavioral model has been considered. The Hazus code is utilized to provide the fragility curves and also to indicate the failures based on the four drift-based performance levels. The IDA analysis is then performed on the models and the results are acquired. The failure index is considered as the maximum drift between the floors of the structures. The IR_3S_MO structure under main earthquakes at the three performance levels (Slight, Moderate, Complete) can withstand 11%, 14% and 88% spectral acceleration more than the IR_3S_LO structure, respectively. This ratio is approximately 10%, 12% and 42% for the IR_3S_RO structure, respectively.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135834658","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}
A large amount of fly ash with a high loss on ignition (over the maximum allowance value stipulated by ASTM C618) is being released and increasing daily in Vietnam. The recycling of this fly ash is still limited, while a big remaining part is disposed of in storage yards, causing environmental pollution. On the other hand, the demand for high-strength mortar as a repair material is increasing for high-rise buildings and important projects, gradually depleting natural resources. However, the application of this fly ash in the production of mortar is restricted in the literature. In this study, local fly ash with a high loss on ignition is used to replace 0%, 15%, 30%, 45%, and 60% cement content in producing high-flowability and high-strength mortar. Changes in the fresh and hardened mortar properties were systematically investigated using samples produced with various fly ash contents. Test results indicate that the effect of impurities in fly ash on the mortar’s workability can be neglected due to the spherical shape of fly ash. The unit weight, thermal conductivity, and drying shrinkage of mortars decreased with increasing fly ash content. Although some other properties of mortar are reduced due to the use of high loss-on-ignition fly ash, all mortars produced in this study still showed good quality with the presence of silica fume. In addition, the relationships between compressive strength and flexural strength with ultrasonic pulse velocity were established to predict the strength of mortar in a non-destructive method.
{"title":"Incorporation of High Loss-on-ignition Fly Ash in Producing High-strength Flowable Mortar","authors":"Si-Huy Ngo, Ngoc Tan Nguyen, Thi-Hong Mai","doi":"10.3311/ppci.22604","DOIUrl":"https://doi.org/10.3311/ppci.22604","url":null,"abstract":"A large amount of fly ash with a high loss on ignition (over the maximum allowance value stipulated by ASTM C618) is being released and increasing daily in Vietnam. The recycling of this fly ash is still limited, while a big remaining part is disposed of in storage yards, causing environmental pollution. On the other hand, the demand for high-strength mortar as a repair material is increasing for high-rise buildings and important projects, gradually depleting natural resources. However, the application of this fly ash in the production of mortar is restricted in the literature. In this study, local fly ash with a high loss on ignition is used to replace 0%, 15%, 30%, 45%, and 60% cement content in producing high-flowability and high-strength mortar. Changes in the fresh and hardened mortar properties were systematically investigated using samples produced with various fly ash contents. Test results indicate that the effect of impurities in fly ash on the mortar’s workability can be neglected due to the spherical shape of fly ash. The unit weight, thermal conductivity, and drying shrinkage of mortars decreased with increasing fly ash content. Although some other properties of mortar are reduced due to the use of high loss-on-ignition fly ash, all mortars produced in this study still showed good quality with the presence of silica fume. In addition, the relationships between compressive strength and flexural strength with ultrasonic pulse velocity were established to predict the strength of mortar in a non-destructive method.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135345090","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}
Ikhlasse Kheira Asmouni, Mohammed Mekki, Mohammed Bensafi
Pounding between buildings that are not sufficiently separated has been observed several times during earthquakes. This destructive impact may severely damage the structure and lead to its collapse. Although it is impossible to completely eliminate such losses, measures can be taken to minimize them. This article investigates the effect of the variability of structural parameters, soil parameters, and seismic action on the seismic response of two colliding buildings, taking the soil-structure interaction (SSI) into account. Two adjacent structures closely separated, modeled as inelastic lumped mass systems with different structural characteristics, were considered in this study. Both structures were modeled in the analysis using multi-degree-of-freedom (MDOF) systems, and the pounding was simulated using the modified linear viscoelastic model. The analysis was conducted in two cases: probabilistic analysis and deterministic analysis. Probability curves were established to analyze the effect of the variability of the parameters on the responses of the two colliding buildings. The comparison between the two analyses indicates that the probabilistic analysis is more precise than the deterministic analysis. It has been indicated that taking into account the variability of structural parameters, soil parameters, and seismic action is efficient in determining the realistic behavior of colliding buildings. Additionally, pounding is more critical in the case of buildings founded on very soft soil, followed by those on soft soil, then on hard soil, and finally on rocky soil.
{"title":"Seismic Behavior of Colliding Buildings, Incorporating Soil-structure Interaction and Accounting for Variability in Structural Parameters, Soil Parameters, and Seismic Action","authors":"Ikhlasse Kheira Asmouni, Mohammed Mekki, Mohammed Bensafi","doi":"10.3311/ppci.22921","DOIUrl":"https://doi.org/10.3311/ppci.22921","url":null,"abstract":"Pounding between buildings that are not sufficiently separated has been observed several times during earthquakes. This destructive impact may severely damage the structure and lead to its collapse. Although it is impossible to completely eliminate such losses, measures can be taken to minimize them. This article investigates the effect of the variability of structural parameters, soil parameters, and seismic action on the seismic response of two colliding buildings, taking the soil-structure interaction (SSI) into account. Two adjacent structures closely separated, modeled as inelastic lumped mass systems with different structural characteristics, were considered in this study. Both structures were modeled in the analysis using multi-degree-of-freedom (MDOF) systems, and the pounding was simulated using the modified linear viscoelastic model. The analysis was conducted in two cases: probabilistic analysis and deterministic analysis. Probability curves were established to analyze the effect of the variability of the parameters on the responses of the two colliding buildings. The comparison between the two analyses indicates that the probabilistic analysis is more precise than the deterministic analysis. It has been indicated that taking into account the variability of structural parameters, soil parameters, and seismic action is efficient in determining the realistic behavior of colliding buildings. Additionally, pounding is more critical in the case of buildings founded on very soft soil, followed by those on soft soil, then on hard soil, and finally on rocky soil.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134958026","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}
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