Pub Date : 2020-05-24DOI: 10.22075/JRCE.2020.17519.1333
Amir Hoshang Ahakhaveissy, M. Malekshahi
Given the sophisticated nature of the blast phenomenon in relation to structures, it is of significance to accurately investigate the structure behavior under blast loads. Due to its rapid and transient nature, blast loading is one of the most important dynamic loadings on the structures. Since masonry materials are widely used as the partition and bearing walls in the existing and newly-built structures, the current research aims to investigate the buried blast effects on unreinforced masonry structures. In order to apply the blast load on a crater as time history, it is required to determine the maximum free field pressure caused by the blast. Accordingly, Finite Element Model Updating (FEMU) was used to calculate the maximum free-field pressure. Thus, for a non-linear dynamic analysis of a blast-loaded structure, a code written in FORTRAN was used. Mohr-Coulomb yield surface with tensile and compression cap and classic Mohr-Coulomb yield surface were used for the structure and the soil modeling, respectively. The comparison of the numerical analysis results in FEMU to field data shows a good consistency between the numerical results and the field data.
{"title":"Experimental Study of Masonry Structure Under Impact Loading and Comparing it with Numerical Modeling Results via Finite Element Model Updating","authors":"Amir Hoshang Ahakhaveissy, M. Malekshahi","doi":"10.22075/JRCE.2020.17519.1333","DOIUrl":"https://doi.org/10.22075/JRCE.2020.17519.1333","url":null,"abstract":"Given the sophisticated nature of the blast phenomenon in relation to structures, it is of significance to accurately investigate the structure behavior under blast loads. Due to its rapid and transient nature, blast loading is one of the most important dynamic loadings on the structures. Since masonry materials are widely used as the partition and bearing walls in the existing and newly-built structures, the current research aims to investigate the buried blast effects on unreinforced masonry structures. In order to apply the blast load on a crater as time history, it is required to determine the maximum free field pressure caused by the blast. Accordingly, Finite Element Model Updating (FEMU) was used to calculate the maximum free-field pressure. Thus, for a non-linear dynamic analysis of a blast-loaded structure, a code written in FORTRAN was used. Mohr-Coulomb yield surface with tensile and compression cap and classic Mohr-Coulomb yield surface were used for the structure and the soil modeling, respectively. The comparison of the numerical analysis results in FEMU to field data shows a good consistency between the numerical results and the field data.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78056084","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 : 2020-05-23DOI: 10.22075/JRCE.2020.15707.1294
A. Hamzenezhadi, M. Sharbatdar
The application of external post-tensioned steel bars as an effective way to strengthen an existing bridge has been so far used in many different countries. In recent decades, however, they have been replaced by bars made from Carbon Fiber Reinforced Polymer (CFRP), as a material with high tensile strength and corrosion resistance, to address several concerns with steel bars such as their application costs and difficulties, and also their durability. Post-tensioning these sheets can be a new efficient method in strengthening the beams and utilizing the high strength of these materials. This study has focused on the flexural behavior of beams reinforced by Post-tensioned non-bonded CFRP sheets. 15 beams were categorized in 3 groups of 5m-, 10m-, and 15m-span in order to evaluate the effect of some parameters such as level of post-tensioning, sheet length, and beam span on its load capacity, failure mode, ductility, and cracks behavior. The results indicate that even though the increase in post-tensioning levels improves the effectiveness of the method, but this capacity improvement is much more for small span beams especially when CFRP sheets are 90% of the beam span, compared to long-span beams. There has been a noticeable capacity increase around 50% in the beams when decreasing the sheet length from 90% to 45% of the beam span and also causing an 11-14% increase in ductility in various conditions.
{"title":"Flexural Strengthening of Deficient Reinforced Concrete Beams with Post-Tensioned Carbon Composites using Finite Element Modelling","authors":"A. Hamzenezhadi, M. Sharbatdar","doi":"10.22075/JRCE.2020.15707.1294","DOIUrl":"https://doi.org/10.22075/JRCE.2020.15707.1294","url":null,"abstract":"The application of external post-tensioned steel bars as an effective way to strengthen an existing bridge has been so far used in many different countries. In recent decades, however, they have been replaced by bars made from Carbon Fiber Reinforced Polymer (CFRP), as a material with high tensile strength and corrosion resistance, to address several concerns with steel bars such as their application costs and difficulties, and also their durability. Post-tensioning these sheets can be a new efficient method in strengthening the beams and utilizing the high strength of these materials. This study has focused on the flexural behavior of beams reinforced by Post-tensioned non-bonded CFRP sheets. 15 beams were categorized in 3 groups of 5m-, 10m-, and 15m-span in order to evaluate the effect of some parameters such as level of post-tensioning, sheet length, and beam span on its load capacity, failure mode, ductility, and cracks behavior. The results indicate that even though the increase in post-tensioning levels improves the effectiveness of the method, but this capacity improvement is much more for small span beams especially when CFRP sheets are 90% of the beam span, compared to long-span beams. There has been a noticeable capacity increase around 50% in the beams when decreasing the sheet length from 90% to 45% of the beam span and also causing an 11-14% increase in ductility in various conditions.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84238902","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 : 2020-05-23DOI: 10.22075/JRCE.2020.19922.1392
A. Doostmohamadi, A. V. Oskouei, A. Kheyroddin
One of the common methods to create bond strength in reinforced concrete is providing development length. The bond strength of glass fiber reinforced polymer (GFRP) bar is inherently poor due to its shape, as well as its inadequate mechanical interlocking with concrete. Therefore, providing sufficient development length in this bar is different and more conservative in comparison with steel bars. In this study, three types of concrete are selected, namely normal-weight concrete (NWC), light-weight concrete (LWC), and light-weight fiber reinforced concrete (LFRC). In order to investigate the adequate development length required for GFRP bars and its relation with the concrete type and compressive strength, for Each type of concrete, two different mix designs which have various compressive strengths are considered. 18 cube specimens are fabricated and the direct pull-out test is performed. The results indicate that, in all types of concrete, as the compressive strength increases, the bond strength between concrete and rebar augments. In addition, assessing the bond strength of different types of concrete demonstrates that the use of LWC, due to its inherent weakness of aggregates interlocking, causes pre-mature cracks and loss of the bond strength compared to NWC. Furthermore, LFRC mixtures containing 0.3% and 0.5% macro-synthetic fiber volume fraction reveal that the presence of fibers can be effective in controlling cracks and increases the bond strength between GFRP bars and concrete. As a result, with the increase of the bond strength between the GFRP bar and the concrete, the ultimate capacity of the concrete cross-section augments.
{"title":"An Experimental Study on Effect of Concrete Type on Bond Strength of GFRP Bars","authors":"A. Doostmohamadi, A. V. Oskouei, A. Kheyroddin","doi":"10.22075/JRCE.2020.19922.1392","DOIUrl":"https://doi.org/10.22075/JRCE.2020.19922.1392","url":null,"abstract":"One of the common methods to create bond strength in reinforced concrete is providing development length. The bond strength of glass fiber reinforced polymer (GFRP) bar is inherently poor due to its shape, as well as its inadequate mechanical interlocking with concrete. Therefore, providing sufficient development length in this bar is different and more conservative in comparison with steel bars. In this study, three types of concrete are selected, namely normal-weight concrete (NWC), light-weight concrete (LWC), and light-weight fiber reinforced concrete (LFRC). In order to investigate the adequate development length required for GFRP bars and its relation with the concrete type and compressive strength, for Each type of concrete, two different mix designs which have various compressive strengths are considered. 18 cube specimens are fabricated and the direct pull-out test is performed. The results indicate that, in all types of concrete, as the compressive strength increases, the bond strength between concrete and rebar augments. In addition, assessing the bond strength of different types of concrete demonstrates that the use of LWC, due to its inherent weakness of aggregates interlocking, causes pre-mature cracks and loss of the bond strength compared to NWC. Furthermore, LFRC mixtures containing 0.3% and 0.5% macro-synthetic fiber volume fraction reveal that the presence of fibers can be effective in controlling cracks and increases the bond strength between GFRP bars and concrete. As a result, with the increase of the bond strength between the GFRP bar and the concrete, the ultimate capacity of the concrete cross-section augments.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"1 1","pages":"52-70"},"PeriodicalIF":0.0,"publicationDate":"2020-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88131053","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 : 2020-05-11DOI: 10.22075/JRCE.2020.19043.1358
Y. Sharifi, Mahmoud Hosainpoor
Artificial neural networks (ANNs) as a powerful approach have been widely utilized to demonstrate some of the engineering problems. A three-layer ANN including three neurons in the hidden layer is considered to produce a verified pattern for assessing the compressive strength of concrete incorporating metakaolin (MK). For this purpose, an extensive database including 469 experimental specimens was obtained from the literature. Next, novel equations utilizing the developed ANN approach were developed to measure the compressive strength of concrete mixtures incorporating MK. To examine the model accuracy a comparison between the proposed formulas based ANN and an empirical formula based nonlinear least-squares regression (NLSR) was carried out. The results show that the proposed formula based on the ANN yields a higher correlation coefficient and fewer errors compared to the NLSR method. An analysis based weights incorporating was utilized to show the significance of input variables. Accordingly, the ratio of fine aggregate to coarse aggregate exerts a dominant influence on the compressive strength of the concretes containing MK.
{"title":"Compressive strength assessment of concrete containing metakaolin using ANN","authors":"Y. Sharifi, Mahmoud Hosainpoor","doi":"10.22075/JRCE.2020.19043.1358","DOIUrl":"https://doi.org/10.22075/JRCE.2020.19043.1358","url":null,"abstract":"Artificial neural networks (ANNs) as a powerful approach have been widely utilized to demonstrate some of the engineering problems. A three-layer ANN including three neurons in the hidden layer is considered to produce a verified pattern for assessing the compressive strength of concrete incorporating metakaolin (MK). For this purpose, an extensive database including 469 experimental specimens was obtained from the literature. Next, novel equations utilizing the developed ANN approach were developed to measure the compressive strength of concrete mixtures incorporating MK. To examine the model accuracy a comparison between the proposed formulas based ANN and an empirical formula based nonlinear least-squares regression (NLSR) was carried out. The results show that the proposed formula based on the ANN yields a higher correlation coefficient and fewer errors compared to the NLSR method. An analysis based weights incorporating was utilized to show the significance of input variables. Accordingly, the ratio of fine aggregate to coarse aggregate exerts a dominant influence on the compressive strength of the concretes containing MK.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90419684","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 : 2020-05-01DOI: 10.22075/JRCE.2019.16186.1306
A. Shahabi, Gholamreza Zamani Ahari, M. Barghian
Seismic isolation is a method to reduce the destructive effects of earthquakes on a structure in which the structure is separated from its foundation by devices called seismic isolators. As a result, the horizontal movements of the earthquake transmitted to the structure are reduced. The seismic isolation is used for both newly constructed structures as well as for retrofitting the existing buildings. Due to the appropriate functioning of the isolators in past earthquakes, many structures are now equipped with these earthquake-resistant systems. So far, some review research works have been conducted on the seismic isolation techniques but in the limited and regional application form. In this paper, a historical evolutionary review of the isolation techniques has been conducted in chronological order. The methods of seismic isolation have been categorized based on their mechanism. The advantages and disadvantages of these methods are discussed. In addition, the latest advances and new methods developed in this field have been introduced.
{"title":"Base Isolation Systems – A State of the Art Review According to Their Mechanism","authors":"A. Shahabi, Gholamreza Zamani Ahari, M. Barghian","doi":"10.22075/JRCE.2019.16186.1306","DOIUrl":"https://doi.org/10.22075/JRCE.2019.16186.1306","url":null,"abstract":"Seismic isolation is a method to reduce the destructive effects of earthquakes on a structure in which the structure is separated from its foundation by devices called seismic isolators. As a result, the horizontal movements of the earthquake transmitted to the structure are reduced. The seismic isolation is used for both newly constructed structures as well as for retrofitting the existing buildings. Due to the appropriate functioning of the isolators in past earthquakes, many structures are now equipped with these earthquake-resistant systems. So far, some review research works have been conducted on the seismic isolation techniques but in the limited and regional application form. In this paper, a historical evolutionary review of the isolation techniques has been conducted in chronological order. The methods of seismic isolation have been categorized based on their mechanism. The advantages and disadvantages of these methods are discussed. In addition, the latest advances and new methods developed in this field have been introduced.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"57 1","pages":"37-61"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84703902","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 : 2020-05-01DOI: 10.22075/JRCE.2019.16139.1305
M. Ghannadi, S. F. Saghravani, H. Niazmand
Two-phase flow regimes are affected by conduit position, alignment, geometry, flow direction, physical characteristics, and flow rate of each phase as well as the heat flux toward the boundaries. Due to the importance of two-phase flow, numerous regimes have been identified. The first step in studying micro-bubble formation inside a venturi tube is to recognize the type of flow regimes. In this study, which is devoted to the study of micro-bubble formation, a numerical investigation by OpenFOAM software and a VOF model was conducted. Results suggest that flow regime inside the venturi tube is roughly similar to flow regimes inside the horizontal tubes. For having bubble flow and consequently forming micro-bubble, flow rate of gas phase should be very smaller than liquid phase flow rate while the air inlet diameter should be chosen much smaller than water input diameter. Numerical simulations indicate that the best results are achieved for the water velocity of about 1-2m/s.
{"title":"Numerical Analysis of Water and Air in Venturi Tube to Produce Micro-Bubbles","authors":"M. Ghannadi, S. F. Saghravani, H. Niazmand","doi":"10.22075/JRCE.2019.16139.1305","DOIUrl":"https://doi.org/10.22075/JRCE.2019.16139.1305","url":null,"abstract":"Two-phase flow regimes are affected by conduit position, alignment, geometry, flow direction, physical characteristics, and flow rate of each phase as well as the heat flux toward the boundaries. Due to the importance of two-phase flow, numerous regimes have been identified. The first step in studying micro-bubble formation inside a venturi tube is to recognize the type of flow regimes. In this study, which is devoted to the study of micro-bubble formation, a numerical investigation by OpenFOAM software and a VOF model was conducted. Results suggest that flow regime inside the venturi tube is roughly similar to flow regimes inside the horizontal tubes. For having bubble flow and consequently forming micro-bubble, flow rate of gas phase should be very smaller than liquid phase flow rate while the air inlet diameter should be chosen much smaller than water input diameter. Numerical simulations indicate that the best results are achieved for the water velocity of about 1-2m/s.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"6 1","pages":"114-125"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82524151","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 : 2020-05-01DOI: 10.22075/JRCE.2019.10841.1175
Farzad Farokhzad, M. Shabani, A. Hasanpour
There are various methods for stabilizing excavations in urban areas which one of them is the nailing method. Designing a nailing system and analyzing the performance of excavations is done by various software applications. One of these computer programs is PAXIS software which run based on the finite element method (FEM). In the present study, a numerical analysis of the performance of the excavations was investigated under different soil model and the most appropriate model was introduced. In addition, the excavation performance was evaluated based on certain designing conditions affected by the soil resistance specifications (cohesion and internal friction angle) and surcharge. The results indicated that, using an appropriate behavioral model which contains increasing soil stiffness with depth, shows results close to reality. They also indicated that under certain designing conditions, the lateral deformation of the soil nail wall and ground settlement decrease as soil resistance specifications increase.
{"title":"Investigating Stabilized Excavations Using Soil Nailing Method in Urban Context","authors":"Farzad Farokhzad, M. Shabani, A. Hasanpour","doi":"10.22075/JRCE.2019.10841.1175","DOIUrl":"https://doi.org/10.22075/JRCE.2019.10841.1175","url":null,"abstract":"There are various methods for stabilizing excavations in urban areas which one of them is the nailing method. Designing a nailing system and analyzing the performance of excavations is done by various software applications. One of these computer programs is PAXIS software which run based on the finite element method (FEM). In the present study, a numerical analysis of the performance of the excavations was investigated under different soil model and the most appropriate model was introduced. In addition, the excavation performance was evaluated based on certain designing conditions affected by the soil resistance specifications (cohesion and internal friction angle) and surcharge. The results indicated that, using an appropriate behavioral model which contains increasing soil stiffness with depth, shows results close to reality. They also indicated that under certain designing conditions, the lateral deformation of the soil nail wall and ground settlement decrease as soil resistance specifications increase.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"45 1","pages":"126-138"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74570607","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 : 2020-05-01DOI: 10.22075/JRCE.2019.17394.1325
Z. Sabzi, A. Fakher
One practical excavation support system is the inclined struts connected to adjacent buildings. This method is very common in small excavations, because of simplicity and minimum cost, when soil is cohesive and depth of excavation is less than stability depth (Hcr) but adjacent structures is at risk of damage due to weakness, old age or lack of proper skeleton frame. Although this method has been used in many small excavations, it is not entirely investigated. This study describes the performance of struts based on field observations and the results of numerical analysis. A small strain constitutive model (Duncan-Chang) was used for analysis. The efficiency of struts was evaluated by comparing the movements of the real case of excavation with struts and the same case but without struts. The results indicate that movements are decreased substantially using struts. A mechanism of struts during excavation is proposed and the effect of installation of the inclined strut on deformation patterns is discussed. The study introduces simple instrumentation designed in the course of the study that can be used in common engineering practice for small to medium-sized excavations.
{"title":"An Investigation into the Performance of Excavation with Inclined Struts Connected to Adjacent Buildings","authors":"Z. Sabzi, A. Fakher","doi":"10.22075/JRCE.2019.17394.1325","DOIUrl":"https://doi.org/10.22075/JRCE.2019.17394.1325","url":null,"abstract":"One practical excavation support system is the inclined struts connected to adjacent buildings. This method is very common in small excavations, because of simplicity and minimum cost, when soil is cohesive and depth of excavation is less than stability depth (Hcr) but adjacent structures is at risk of damage due to weakness, old age or lack of proper skeleton frame. Although this method has been used in many small excavations, it is not entirely investigated. This study describes the performance of struts based on field observations and the results of numerical analysis. A small strain constitutive model (Duncan-Chang) was used for analysis. The efficiency of struts was evaluated by comparing the movements of the real case of excavation with struts and the same case but without struts. The results indicate that movements are decreased substantially using struts. A mechanism of struts during excavation is proposed and the effect of installation of the inclined strut on deformation patterns is discussed. The study introduces simple instrumentation designed in the course of the study that can be used in common engineering practice for small to medium-sized excavations.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"356 1","pages":"139-152"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76419170","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 : 2020-05-01DOI: 10.22075/JRCE.2020.18210.1348
S. Karimpour, S. Gohari
The major damage of hydraulic structures at river crossing occurs during floods and culverts is the structure which use as a part of drainage system in ephemeral streams. Failure in structures is caused for different reasons but pier and abutment scour is the main reason. The presence of debris causes larger scours and sediment removal compared to the absence of debris accumulation. In this study, the common problem of the flow blockage at culvert inlets is investigated applying a hydraulic model set in laboratory. Experiments were performed to understand the changes and interaction of scour depth over a range of downstream flow depths, ht and densimetric Froude number, Fo. The debris accumulation is modelled by rectangular plates of constant width (30 cm) and various heights (4, 8, 12, 16 cm) set at the culvert entrance. When culvert inlet area decreased by the smallest solid debris accumulation - which covered 20% of inlet area-, the upstream water level raised up to 12% and by the biggest solid debris size- which covered 80% of inlet area- water level increased up to 60%. Debris accumulation causes larger scours and sediment removal, so the scour hole area extended extremely in flow direction. A new maximum scour depth predictor equation has been proposed to predict the effects of debris accumulation at culvert inlet on downstream scour. This equation is well fitted with the experimental results of the current study and the results of experiments from the previous studies used to analyze presented formula.
{"title":"An Experimental Study on the Effects of Debris Accumulation at the Culvert Inlet on Downstream Scour","authors":"S. Karimpour, S. Gohari","doi":"10.22075/JRCE.2020.18210.1348","DOIUrl":"https://doi.org/10.22075/JRCE.2020.18210.1348","url":null,"abstract":"The major damage of hydraulic structures at river crossing occurs during floods and culverts is the structure which use as a part of drainage system in ephemeral streams. Failure in structures is caused for different reasons but pier and abutment scour is the main reason. The presence of debris causes larger scours and sediment removal compared to the absence of debris accumulation. In this study, the common problem of the flow blockage at culvert inlets is investigated applying a hydraulic model set in laboratory. Experiments were performed to understand the changes and interaction of scour depth over a range of downstream flow depths, ht and densimetric Froude number, Fo. The debris accumulation is modelled by rectangular plates of constant width (30 cm) and various heights (4, 8, 12, 16 cm) set at the culvert entrance. When culvert inlet area decreased by the smallest solid debris accumulation - which covered 20% of inlet area-, the upstream water level raised up to 12% and by the biggest solid debris size- which covered 80% of inlet area- water level increased up to 60%. Debris accumulation causes larger scours and sediment removal, so the scour hole area extended extremely in flow direction. A new maximum scour depth predictor equation has been proposed to predict the effects of debris accumulation at culvert inlet on downstream scour. This equation is well fitted with the experimental results of the current study and the results of experiments from the previous studies used to analyze presented formula.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"47 1","pages":"184-199"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78224257","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 : 2020-05-01DOI: 10.22075/JRCE.2019.17206.1319
A. Mortezaei, M. B. Payganeh
The significance of the seismic rotational components have been overlooked in the seismic evaluation of structural behavior. As researchers have measured seismic components more accurately using sensitive rotational velocity sensor, it was observed that the magnitude of rotational components is considerable and could not be neglected. Hence, some parts of seismic damage or failure of structures cannot be exclusively attributed to the translational components. In this regard, this paper used seven accelerograms in which rotational components were measured by advanced sensors. The considered RC buildings which designed as per intermediate moment-resisting frame system were analyzed using OpenSees in nonlinear dynamic domain. In the numerical modeling, lumped plasticity model was used to simulate the behavior of RC component members considering the rotational motions and soil-structure interaction as main parameters. The results of numerous nonlinear time history analyses showed that the contribution of rotational components to the seismic behavior of RC frames is considerable and should be included in the seismic design codes.
{"title":"Seismic Damage Assessment of RC Buildings Subjected to the Rotational Ground Motion Records Considering Soil-Structure Interaction","authors":"A. Mortezaei, M. B. Payganeh","doi":"10.22075/JRCE.2019.17206.1319","DOIUrl":"https://doi.org/10.22075/JRCE.2019.17206.1319","url":null,"abstract":"The significance of the seismic rotational components have been overlooked in the seismic evaluation of structural behavior. As researchers have measured seismic components more accurately using sensitive rotational velocity sensor, it was observed that the magnitude of rotational components is considerable and could not be neglected. Hence, some parts of seismic damage or failure of structures cannot be exclusively attributed to the translational components. In this regard, this paper used seven accelerograms in which rotational components were measured by advanced sensors. The considered RC buildings which designed as per intermediate moment-resisting frame system were analyzed using OpenSees in nonlinear dynamic domain. In the numerical modeling, lumped plasticity model was used to simulate the behavior of RC component members considering the rotational motions and soil-structure interaction as main parameters. The results of numerous nonlinear time history analyses showed that the contribution of rotational components to the seismic behavior of RC frames is considerable and should be included in the seismic design codes.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"17 1","pages":"62-80"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86244456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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