Pub Date : 2018-11-05DOI: 10.4172/2165-784X.1000325
Marie Judith Kundwa, Constant Mahame, T. Bigirimana, Pascaline Sanga
The government of Rwanda through its Ministry of Infrastructure (MININFRA), the authority in charge of energy has initiated different initiatives aimed at finding long term solutions to energy shortage in the country where no investment has been done the last 20 years in electricity generation. Among these solutions, biogas has been identified as one of the sector to be developed. Energy plays a major role in development process of every country. This research is conducted in order to handle energy shortage problems in secondary schools located in rural areas by using a modern biogas. To achieve the aims of this research, the field survey was conducted at G. S de Ntarama and data about numbers of students and teachers, type and amount of waste produced, and impacts of lack of electricity on education were collected through interviews and questionnaires. The data were analyzed and the size of digester was estimated to be 118.524 m 3 . In addition to reducing the emission of carbon dioxide to 7 times lesser than which is emitted by firewood, it was also found that the use of biogas proves to be economical by covering the cost of firewood consumed in one month to five months. The produced energy allocated both in lighting for 4 hours and cooking for 3 hours was proved to be more advantageous and cost effective. The use of modern biogas contributes to the quality of education, environmental protection, agriculture productivity, and improve the lives of Rwandan people in general.
卢旺达政府通过其负责能源的基础设施部(MININFRA)发起了不同的倡议，旨在为过去20年没有投资发电的国家寻找能源短缺的长期解决方案。在这些解决方案中，沼气已被确定为有待开发的领域之一。能源在每个国家的发展进程中都扮演着重要的角色。本研究是为了利用现代沼气解决农村中学的能源短缺问题。为了实现本研究的目的，在G. S . de Ntarama进行了实地调查，并通过访谈和问卷调查收集了有关学生和教师人数，产生的废物类型和数量以及缺乏电力对教育的影响的数据。经数据分析，估计消化池尺寸为118.524 m3。除了将二氧化碳的排放量减少到木柴排放量的七分之一之外，还发现使用沼气证明是经济的，因为它可以支付一个月至五个月消耗的木柴的费用。4小时的照明和3小时的烹饪所产生的能量被证明是更有利和更经济的。现代沼气的使用有助于提高教育质量、环境保护、农业生产力，并改善卢旺达人民的总体生活。
{"title":"Contribution of Modern Biogas Plant to Energy Source and Environment Protection in Rwanda","authors":"Marie Judith Kundwa, Constant Mahame, T. Bigirimana, Pascaline Sanga","doi":"10.4172/2165-784X.1000325","DOIUrl":"https://doi.org/10.4172/2165-784X.1000325","url":null,"abstract":"The government of Rwanda through its Ministry of Infrastructure (MININFRA), the authority in charge of energy has initiated different initiatives aimed at finding long term solutions to energy shortage in the country where no investment has been done the last 20 years in electricity generation. Among these solutions, biogas has been identified as one of the sector to be developed. Energy plays a major role in development process of every country. This research is conducted in order to handle energy shortage problems in secondary schools located in rural areas by using a modern biogas. To achieve the aims of this research, the field survey was conducted at G. S de Ntarama and data about numbers of students and teachers, type and amount of waste produced, and impacts of lack of electricity on education were collected through interviews and questionnaires. The data were analyzed and the size of digester was estimated to be 118.524 m 3 . In addition to reducing the emission of carbon dioxide to 7 times lesser than which is emitted by firewood, it was also found that the use of biogas proves to be economical by covering the cost of firewood consumed in one month to five months. The produced energy allocated both in lighting for 4 hours and cooking for 3 hours was proved to be more advantageous and cost effective. The use of modern biogas contributes to the quality of education, environmental protection, agriculture productivity, and improve the lives of Rwandan people in general.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76454067","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 : 2018-10-30DOI: 10.4172/2165-784X-C1-015
pArup Saha Chaudhurip
{"title":"Earthquake resistant sustainable steel green buildings made of wide flange rolled sections","authors":"pArup Saha Chaudhurip","doi":"10.4172/2165-784X-C1-015","DOIUrl":"https://doi.org/10.4172/2165-784X-C1-015","url":null,"abstract":"","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72496432","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}
{"title":"Comparative Study of Equivalent Linear and Non-Linear Ground Response Analysis for Rapar District of Kutch, India","authors":"K. Dave, K. Mohan","doi":"10.5281/ZENODO.1474893","DOIUrl":"https://doi.org/10.5281/ZENODO.1474893","url":null,"abstract":"","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86295191","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 : 2018-07-15DOI: 10.22034/JCEE.2020.13438.1349
محمدرضا روستا, داود صداقت شایگان
شوت های تند مجهز به بارشکن سال ها در پروژه های آبیاری به کار رفته اند و پاسخ مقرون به صرفه ای برای کاهش انرژی بوده اند. در این سرریزها پایه های بارشکن می تواند به صورت مانع عمل کند و سبب استهلاک انرژی آب شود و آب در مسیر حرکت خود دارای سرعت نسبتا کمی خواهد بود. سرعت خروجی کم و اقتصادی بودن ،بدون توجه به بلندی آبشار از محاسن این نوع سرریزها دانست. هدف اصلی از این تحقیق، ارزیابی توانایی نرم افزار Flow3D در شبیه سازی عددی جریان عبوری از سرریزهای دندانه دار می باشد.نرم افزارFlow3D یک نرم افزار قوی در زمینه دینامیک سیالات محاسباتی است که برای حل مسائل با هندسه پیچیده مورد استفاده قرار میگیرد. در این تحقیق برای صحت سنجی نرم افزار به منظور تخمین پارامترهای جریان عبوری از سرریز دندانه دار، از نتایج آزمایشگاهی و همچنین جهت شبیهسازی پروفیل سطح آب از روش حجم سیال (VOF) استفاده شده و با بررسی نتایج آن با نتایج آزمایشگاهی دقت مدل ارزیابی گردیده است. نتایج نشان میدهد که مدل Flow3D با دقت بالایی میتواند جهت شبیهسازی جریان عبوری از سرریزهای دندانه دار مورد استفاده قرار گیرد. همچنین جریان با دبی های مختلف روی شیب مجهز به بارشکن با پنج نوع مانع متفاوت بوسیله نرم افزار Flow3D شبیه سازی شد و پس از تحلیل انرژی مستهلک شده مشخص گردید شوت مجهز به بارشکن با بلوک های نیم دایره افقی بهترین عملکرد را در بین پنج مدل بررسی شده دارا است
{"title":"بررسی اثر تغییر حالت بلوک های سرریزهای دندانه دار بر استهلاک انرژی جریان با مدل Flow3D","authors":"محمدرضا روستا, داود صداقت شایگان","doi":"10.22034/JCEE.2020.13438.1349","DOIUrl":"https://doi.org/10.22034/JCEE.2020.13438.1349","url":null,"abstract":"شوت های تند مجهز به بارشکن سال ها در پروژه های آبیاری به کار رفته اند و پاسخ مقرون به صرفه ای برای کاهش انرژی بوده اند. در این سرریزها پایه های بارشکن می تواند به صورت مانع عمل کند و سبب استهلاک انرژی آب شود و آب در مسیر حرکت خود دارای سرعت نسبتا کمی خواهد بود. سرعت خروجی کم و اقتصادی بودن ،بدون توجه به بلندی آبشار از محاسن این نوع سرریزها دانست. هدف اصلی از این تحقیق، ارزیابی توانایی نرم افزار Flow3D در شبیه سازی عددی جریان عبوری از سرریزهای دندانه دار می باشد.نرم افزارFlow3D یک نرم افزار قوی در زمینه دینامیک سیالات محاسباتی است که برای حل مسائل با هندسه پیچیده مورد استفاده قرار میگیرد. در این تحقیق برای صحت سنجی نرم افزار به منظور تخمین پارامترهای جریان عبوری از سرریز دندانه دار، از نتایج آزمایشگاهی و همچنین جهت شبیهسازی پروفیل سطح آب از روش حجم سیال (VOF) استفاده شده و با بررسی نتایج آن با نتایج آزمایشگاهی دقت مدل ارزیابی گردیده است. نتایج نشان میدهد که مدل Flow3D با دقت بالایی میتواند جهت شبیهسازی جریان عبوری از سرریزهای دندانه دار مورد استفاده قرار گیرد. همچنین جریان با دبی های مختلف روی شیب مجهز به بارشکن با پنج نوع مانع متفاوت بوسیله نرم افزار Flow3D شبیه سازی شد و پس از تحلیل انرژی مستهلک شده مشخص گردید شوت مجهز به بارشکن با بلوک های نیم دایره افقی بهترین عملکرد را در بین پنج مدل بررسی شده دارا است","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76057442","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 : 2018-07-06DOI: 10.4172/2165-784X.1000318
Mahmoud Mazen Hilles and Mohammed M Ziara
Effects of alkali resistant glass fiber reinforced polymer (AR-GFRP) with various proportions on the mechanical behavior of high strength concrete (HSC) were investigated on this study. Concrete mixtures were prepared with various proportions of AR-GFRP typically 0.3, 0.6, 0.9, and 1.2 by weight of cement. The mixtures were cast and tested for compressive, splitting tensile and flexural strengths in accordance to ASTM standards. The experimental results showed that the strengths increase as fiber percentage increases; the compressive strength increased from 57.85 to 66.6 MPa, the splitting tensile strength increased from 3.06 to 4.92 MPa, and the flexural strength increased from 4.84 to 7.27 MPa when fiber percentage increased from 0.0 to 1.2 respectively. In comparison with plain HSC control specimens that showed destructive sudden failure, the formation of cracks that led to failure in the specimens with AR-GFRP was gradual as the fiber percentage increases. Hence it can be concluded that the presence of fibers in the matrix has contributed towards prevent sudden crack formation and thus enhancing concrete ductility.
{"title":"Mechanical Behavior of High Strength Concrete Reinforced with GlassFiber Reinforced Polymer","authors":"Mahmoud Mazen Hilles and Mohammed M Ziara","doi":"10.4172/2165-784X.1000318","DOIUrl":"https://doi.org/10.4172/2165-784X.1000318","url":null,"abstract":"Effects of alkali resistant glass fiber reinforced polymer (AR-GFRP) with various proportions on the mechanical behavior of high strength concrete (HSC) were investigated on this study. Concrete mixtures were prepared with various proportions of AR-GFRP typically 0.3, 0.6, 0.9, and 1.2 by weight of cement. The mixtures were cast and tested for compressive, splitting tensile and flexural strengths in accordance to ASTM standards. The experimental results showed that the strengths increase as fiber percentage increases; the compressive strength increased from 57.85 to 66.6 MPa, the splitting tensile strength increased from 3.06 to 4.92 MPa, and the flexural strength increased from 4.84 to 7.27 MPa when fiber percentage increased from 0.0 to 1.2 respectively. In comparison with plain HSC control specimens that showed destructive sudden failure, the formation of cracks that led to failure in the specimens with AR-GFRP was gradual as the fiber percentage increases. Hence it can be concluded that the presence of fibers in the matrix has contributed towards prevent sudden crack formation and thus enhancing concrete ductility.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74803255","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 : 2018-06-28DOI: 10.4172/2165-784X.1000314
C. Bob
The paper presents a new approach for obtained the sustainability of the construction works. In the technical literature there are a lot of models which evaluate the sustainability performance of the construction works with high applicability and very comprehensive. In many cases such models show some disadvantage: some models do not cover all three dimensions of the sustainability; all of them include a great number of criteria and many of them are difficult or impossible to quantify; they are focused manly on entire buildings and they can be applied with some difficulties on other types of construction works and activities. The first step to avoid such disadvantages was by proposal a so called specific model with some advantages: high degree of utilization includes only quantitative parameters, covers the three dimensions of sustainability. The second step is presented in this paper by a new approach which takes into account the price of each parameter and finally, the sustainability cost is established. The application of new model is presented on three different construction works. Using of the new approach some advantages are obtained: such calculation is easy understandably by specialists; by using the correction of the mechanical characteristics the most sustainable solution is obtained: costs of main parameters where taken from Romanian practice, but for different zones and countries, such costs will have to be used.
{"title":"A New Approach of a Specific Sustainability Model","authors":"C. Bob","doi":"10.4172/2165-784X.1000314","DOIUrl":"https://doi.org/10.4172/2165-784X.1000314","url":null,"abstract":"The paper presents a new approach for obtained the sustainability of the construction works. In the technical literature there are a lot of models which evaluate the sustainability performance of the construction works with high applicability and very comprehensive. In many cases such models show some disadvantage: some models do not cover all three dimensions of the sustainability; all of them include a great number of criteria and many of them are difficult or impossible to quantify; they are focused manly on entire buildings and they can be applied with some difficulties on other types of construction works and activities. The first step to avoid such disadvantages was by proposal a so called specific model with some advantages: high degree of utilization includes only quantitative parameters, covers the three dimensions of sustainability. The second step is presented in this paper by a new approach which takes into account the price of each parameter and finally, the sustainability cost is established. The application of new model is presented on three different construction works. Using of the new approach some advantages are obtained: such calculation is easy understandably by specialists; by using the correction of the mechanical characteristics the most sustainable solution is obtained: costs of main parameters where taken from Romanian practice, but for different zones and countries, such costs will have to be used.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86872612","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 : 2018-05-29DOI: 10.4172/2165-784X.1000312
M. Maali, Mahmut Kılıç, Merve Sağıroğlu, A. Aydın
In this research, new connection types were suggested, and their behaviors were determined using full-scale experiments. T-shaped combinations created using the IPE standard profile and T-shaped elements are different from those in the literature, which utilize welded plates. Thus, problems occurring at the welds of connections such as the occurrence of fracture points and inability to perform well in place are expected to be eliminated. To recommend the use of weld-less T connections, knowledge of the behavior of the connections was needed. In addition, in this research, the effects of changes in the dimensions of the connection members on the connection behavior were examined for the T-connection type. This provided information about the optimum sizes of the connection elements. The main parameters observed were the evolution of the resistance, stiffness, rotation capacity, ductility of a joint, and energy dissipation. The aim was to provide the necessary data to improve Eurocode 3 and efficiently use residue IPE standard profiles, rather than send them back to the consumption cycle.
{"title":"Experimental Behavior of Bolted T-Stub Connections with IPE Standard Profile","authors":"M. Maali, Mahmut Kılıç, Merve Sağıroğlu, A. Aydın","doi":"10.4172/2165-784X.1000312","DOIUrl":"https://doi.org/10.4172/2165-784X.1000312","url":null,"abstract":"In this research, new connection types were suggested, and their behaviors were determined using full-scale experiments. T-shaped combinations created using the IPE standard profile and T-shaped elements are different from those in the literature, which utilize welded plates. Thus, problems occurring at the welds of connections such as the occurrence of fracture points and inability to perform well in place are expected to be eliminated. To recommend the use of weld-less T connections, knowledge of the behavior of the connections was needed. In addition, in this research, the effects of changes in the dimensions of the connection members on the connection behavior were examined for the T-connection type. This provided information about the optimum sizes of the connection elements. The main parameters observed were the evolution of the resistance, stiffness, rotation capacity, ductility of a joint, and energy dissipation. The aim was to provide the necessary data to improve Eurocode 3 and efficiently use residue IPE standard profiles, rather than send them back to the consumption cycle.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83404601","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 : 2018-05-24DOI: 10.4172/2165-784X.1000311
G. Hekal
The subject of the overall structural collapse under hazardous loads in reinforced concrete frames has been addressed in various researches. However, most of those studies have examined the column removal scenario where one of columns is removed and the load of this column is applied vertically on the upper face to assess the behavior of the frame until failure. One of the shortcomings of the previous mechanism is that it neglects the main reason for the failure of the column and the impact of that reason on the different elements of the structure. The current work presents a numerical investigation of frame collapse as a result of sudden column failure due to an explosive wave. The frame of study has already been tested in a previous work of the author. It was a reinforced concrete frame that has been cast without an intermediate column and then dynamically loaded in the position of the missing column until collapse. In this study, the behavior of that frame is re-evaluated under the effect of instantaneous removal of the middle column due to explosion loads. Analysis was performed using Abaqus software where frame capacity and failure mode were monitored considering different locations of application of incident wave on the target column. Comparing the obtained results with the original model indicated that both capacity and mode of failure differ significantly by changing the location of application of incident wave.
{"title":"Collapse Analysis of a Reinforced Concrete Frame Due to Middle Column Loss by Explosion","authors":"G. Hekal","doi":"10.4172/2165-784X.1000311","DOIUrl":"https://doi.org/10.4172/2165-784X.1000311","url":null,"abstract":"The subject of the overall structural collapse under hazardous loads in reinforced concrete frames has been addressed in various researches. However, most of those studies have examined the column removal scenario where one of columns is removed and the load of this column is applied vertically on the upper face to assess the behavior of the frame until failure. One of the shortcomings of the previous mechanism is that it neglects the main reason for the failure of the column and the impact of that reason on the different elements of the structure. The current work presents a numerical investigation of frame collapse as a result of sudden column failure due to an explosive wave. The frame of study has already been tested in a previous work of the author. It was a reinforced concrete frame that has been cast without an intermediate column and then dynamically loaded in the position of the missing column until collapse. In this study, the behavior of that frame is re-evaluated under the effect of instantaneous removal of the middle column due to explosion loads. Analysis was performed using Abaqus software where frame capacity and failure mode were monitored considering different locations of application of incident wave on the target column. Comparing the obtained results with the original model indicated that both capacity and mode of failure differ significantly by changing the location of application of incident wave.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75790327","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 : 2018-04-26DOI: 10.4172/2165-784X.1000309
M. Maali, A. Aydın, H. Showkati, S. M. Fatemi, Merve Sağıroğlu
Buckling and post-buckling are among the most important failure factors in thin walled structures. The loadcarrying behavior of cylindrical thin-walled shell structures under external pressure load is strongly dependent upon the nature and magnitude of the initial imperfections. These imperfections are invariably caused by an assortment of manufacturing processes like installing or welding. One of the most important imperfections caused by welding that has been reported to have an essential detrimental effect on the buckling resistance of these shells under external pressure load is longitudinal imperfections. Buckling and post buckling capacity of the shells depend on the H/R and t/ R ratios (H the height, R the radius and t the thickness of a cylindrical shell). The present work discusses the finiteelement models labeled as SS (Shallow Slim), DS (Deep Slim), ST (Shallow Thick) and DT (Deep Thick). The samples of first group are modified to include a line longitudinal imperfection, amplitudes of 0.5t, 1t, 2t, 3t, 4t and 8t in depth (t is the thickness of cylindrical shell). The results presented are in agreement with international codes and theories concerning buckling.
{"title":"Longitudinal Imperfections on Thin Walled Cylindrical Shells","authors":"M. Maali, A. Aydın, H. Showkati, S. M. Fatemi, Merve Sağıroğlu","doi":"10.4172/2165-784X.1000309","DOIUrl":"https://doi.org/10.4172/2165-784X.1000309","url":null,"abstract":"Buckling and post-buckling are among the most important failure factors in thin walled structures. The loadcarrying behavior of cylindrical thin-walled shell structures under external pressure load is strongly dependent upon the nature and magnitude of the initial imperfections. These imperfections are invariably caused by an assortment of manufacturing processes like installing or welding. One of the most important imperfections caused by welding that has been reported to have an essential detrimental effect on the buckling resistance of these shells under external pressure load is longitudinal imperfections. Buckling and post buckling capacity of the shells depend on the H/R and t/ R ratios (H the height, R the radius and t the thickness of a cylindrical shell). The present work discusses the finiteelement models labeled as SS (Shallow Slim), DS (Deep Slim), ST (Shallow Thick) and DT (Deep Thick). The samples of first group are modified to include a line longitudinal imperfection, amplitudes of 0.5t, 1t, 2t, 3t, 4t and 8t in depth (t is the thickness of cylindrical shell). The results presented are in agreement with international codes and theories concerning buckling.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88514617","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 : 2018-04-12DOI: 10.4172/2165-784X.1000308
A. Agha, M. H. Rashid
This research presents a theoretical study to determine the effect of the load eccentricity on the reinforced concrete column strength taking into account the variables: amount of eccentricity ratio (e/h=0.1 and 1.0); amount of longitudinal reinforcement ρ%=1% to 8%; concrete compressive strength ( ' 21,28,35,42,63 84 ); c f = and MPa steel yielding strength ( 414 525 ); y f = and MPa the steel reinforcement distance ratiocondition of loading (Uniaxial and Biaxial bending); shape of the cross section (rectangular and circular) and finally the distribution of the reinforcement on two opposite sides and on four sides. Generally the strength of columns is reduced with existing the load eccentricity and amount of losses in strength increased with increasing the eccentricity amount. The average strength ratio in case of biaxial bending condition is about (82%) of the uniaxial condition in case of (e/h=0.1) and become (55%) in case of (e/h=0.1). For uniaxial bending condition, the average relative column strength is about (75%) in case of (e/h=0.1) and (14%) in case of (e/h=0.1); while for biaxial bending condition, the ratio is (60%) in case of (e/h=0.1) and (8%) in case of (e/ h=0.1). Increasing of concrete compressive strength ( ' ) c f , steel yielding strength ( ) s γ , steel distance ratio ( ) s γ and amount of longitudinal reinforcement (ρ%) cause increasing in column strength and reducing the losses in column strength. Also the results show great effect of the load eccentricity ratio (e/h) and bending condition (uniaxial and biaxial) on the reduction of column strength. The distribution of the reinforcement on two opposite sides gives upper limit results and maximum column strength, compared with the case of when the reinforcement distributed on four sides and rectangular section with circular distribution of the reinforcement, while circular columns gives lower limit results and minimum column strength compared with other cases mentioned above.
本文对考虑偏心比量(e/h=0.1和1.0)的荷载偏心对钢筋混凝土柱强度的影响进行了理论研究;纵向配筋量ρ%=1% ~ 8%;混凝土抗压强度(21、28、35、42、63 84);c f =和MPa钢的屈服强度(414 525);y f =和MPa为钢筋距离比加载条件(单轴和双轴弯曲);截面形状(矩形和圆形)，最后在两个相对的边和四个边的钢筋分布。一般情况下，柱的强度随偏心荷载的存在而降低，强度损失量随偏心荷载的增加而增大。当e/h=0.1时，双轴弯曲条件下的平均强度比约为单轴弯曲条件下的82%，当e/h=0.1时，平均强度比变为55%。单轴弯曲条件下，当e/h=0.1时，柱的平均相对强度约为75%，当e/h=0.1时，平均相对强度约为14%;双轴弯曲条件下，(e/h=0.1)为(60%)，(e/h=0.1)为(8%)。混凝土抗压强度(′)c f、钢筋屈服强度(′)s γ、钢筋间距比(′)s γ和纵向配筋量(ρ%)的增大使柱强度增大，柱强度损失减小。荷载偏心比(e/h)和弯曲条件(单轴和双轴)对柱强度降低有较大影响。相对两侧配筋可得到柱强度的上限结果和最大值，与四周配筋和矩形截面配筋圆形分布的情况相比，圆形柱可得到柱强度的下限结果和最小值，与上述其他情况相比。
{"title":"Effect of Load Eccentricity on the Strength of Concrete Columns","authors":"A. Agha, M. H. Rashid","doi":"10.4172/2165-784X.1000308","DOIUrl":"https://doi.org/10.4172/2165-784X.1000308","url":null,"abstract":"This research presents a theoretical study to determine the effect of the load eccentricity on the reinforced concrete column strength taking into account the variables: amount of eccentricity ratio (e/h=0.1 and 1.0); amount of longitudinal reinforcement ρ%=1% to 8%; concrete compressive strength ( ' 21,28,35,42,63 84 ); c f = and MPa steel yielding strength ( 414 525 ); y f = and MPa the steel reinforcement distance ratiocondition of loading (Uniaxial and Biaxial bending); shape of the cross section (rectangular and circular) and finally the distribution of the reinforcement on two opposite sides and on four sides. Generally the strength of columns is reduced with existing the load eccentricity and amount of losses in strength increased with increasing the eccentricity amount. The average strength ratio in case of biaxial bending condition is about (82%) of the uniaxial condition in case of (e/h=0.1) and become (55%) in case of (e/h=0.1). For uniaxial bending condition, the average relative column strength is about (75%) in case of (e/h=0.1) and (14%) in case of (e/h=0.1); while for biaxial bending condition, the ratio is (60%) in case of (e/h=0.1) and (8%) in case of (e/ h=0.1). Increasing of concrete compressive strength ( ' ) c f , steel yielding strength ( ) s γ , steel distance ratio ( ) s γ and amount of longitudinal reinforcement (ρ%) cause increasing in column strength and reducing the losses in column strength. Also the results show great effect of the load eccentricity ratio (e/h) and bending condition (uniaxial and biaxial) on the reduction of column strength. The distribution of the reinforcement on two opposite sides gives upper limit results and maximum column strength, compared with the case of when the reinforcement distributed on four sides and rectangular section with circular distribution of the reinforcement, while circular columns gives lower limit results and minimum column strength compared with other cases mentioned above.","PeriodicalId":52256,"journal":{"name":"Tumu yu Huanjing Gongcheng Xuebao/Journal of Civil and Environmental Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86981107","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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