Pub Date : 2020-01-20DOI: 10.4236/ojce.2020.101002
G. Ganga, N. Malanda, D. Ngoma, T. Nsongo, M. D. Gadet
This study includes the manufacture of cement stabilized clay bricks with embedded mahogany chips. The impact of this waste and its interaction with water in the bricks was evaluated on the mechanical properties. The compressive strength tests using a universal press were carried out on bricks with and without adding wood chips. The results obtained show that the incorporation of wood chips into the bricks decreases the compressive strength. This reduction in compressive strength led us to conduct an analysis of clay and water as intrinsic factors, before and after incorporation of untreated wood waste. Thus, a mineralogical analysis of the clay with and without mahogany chips was made using an X-ray diffractometer, using an anticathode of cobalt with the line Κα, of wavelength λ = 1789Å. After quantification of the mineral constituents, it is noted that the concentration of SiO2 decreases considerably in the clay with addition of wood chips, resulting in the reduction of the compressive strength in these composite materials (from Rc = 9.26 MPa at 0% of chips to 3.55 MPa at 8%). A mathematical model following the interpolations of Lagrange was then proposed. The analysis of the water resulting from the impregnation of dry wood chips in the water, shows that the water becomes strongly acid (pH = 4.3 at the 7th day of immersion), thus contributing to the reduction of resistance. This analysis of intrinsic factors will allow future studies to take into account the treatment of wood waste by different processes in order to increase the mechanical, thermal and acoustic properties of composite bricks with the same contents, thus generating massive support for the use of its composite materials.
{"title":"Impact of pH Water and Mineralogical Microstructure of Soil Mixed with Wood Waste on the Compressive Strength of Composite Bricks; and Bricks Resistance Modeling","authors":"G. Ganga, N. Malanda, D. Ngoma, T. Nsongo, M. D. Gadet","doi":"10.4236/ojce.2020.101002","DOIUrl":"https://doi.org/10.4236/ojce.2020.101002","url":null,"abstract":"This study includes the manufacture of cement stabilized \u0000clay bricks with embedded mahogany chips. The impact of this waste and its interaction \u0000with water in the bricks was evaluated on the mechanical properties. The compressive \u0000strength tests using a universal press were carried out on bricks with and without \u0000adding wood chips. The results obtained show that the incorporation of wood chips \u0000into the bricks decreases the compressive strength. This reduction in compressive \u0000strength led us to conduct an analysis of clay and water as intrinsic factors, before \u0000and after incorporation of untreated wood \u0000waste. Thus, a mineralogical analysis of the \u0000clay with and without mahogany chips was made using an X-ray diffractometer, using \u0000an anticathode of cobalt with the line Κα, of wavelength λ = 1789Å. After quantification of the mineral constituents, it is noted that the \u0000concentration of SiO2 decreases considerably in the clay with addition of wood chips, resulting in the reduction \u0000of the compressive strength in these composite materials (from Rc = 9.26 MPa at \u00000% of chips to 3.55 MPa at 8%). A mathematical model \u0000following the interpolations of Lagrange was then proposed. The analysis of the \u0000water resulting from the impregnation of dry wood chips in the water, shows that \u0000the water becomes strongly acid (pH = 4.3 at the 7th day of immersion), thus contributing \u0000to the reduction of resistance. This analysis of intrinsic factors will allow future \u0000studies to take into account the treatment of wood waste by different processes \u0000in order to increase the mechanical, thermal and acoustic properties of composite \u0000bricks with the same contents, thus generating massive support for the use of its \u0000composite materials.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123904662","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 : 2020-01-13DOI: 10.4236/ojce.2020.101001
I. Tuhin
Overhead sign-support bridges that allow displaying necessary information for travelers across the multiple lanes in highways often use large message sign panels: static message sign (SMS) panels or dynamic message sign (DMS) panels. Along with conventional SMS panel, the use of DMS panel is increasing in highways over time owing to their effective capability to guide the travelers in real-time. A 230-ft long span 4-chord overhead steel truss bridge attached with SMS and DMS panel has been studied through extensive finite element analysis to observe the structural integrity. The static wind load was applied in model truss for four different configurations as per 2016 AASHTO LRFD design specification. The innovative structural detailing approach for truss end support and connection detailing for toll-equipment supporting frame was proposed based on static analysis. The present study will help engineers to design overhead sign support bridges by ensuring both public safety and structural integrity.
{"title":"Structural Behavior of Long Span Overhead Sign Support Bridges","authors":"I. Tuhin","doi":"10.4236/ojce.2020.101001","DOIUrl":"https://doi.org/10.4236/ojce.2020.101001","url":null,"abstract":"Overhead sign-support bridges that allow displaying necessary information \u0000for travelers across the multiple lanes in highways often use large message \u0000sign panels: static message sign (SMS) panels or dynamic message sign (DMS) \u0000panels. Along with conventional SMS panel, the use of DMS panel is increasing \u0000in highways over time owing to their effective capability to guide the \u0000travelers in real-time. A 230-ft long span 4-chord overhead steel truss bridge \u0000attached with SMS and DMS panel has been studied through extensive finite \u0000element analysis to observe the structural integrity. The static wind load was \u0000applied in model truss for four different configurations as per 2016 AASHTO LRFD design specification. The \u0000innovative structural detailing approach for truss end support and connection \u0000detailing for toll-equipment supporting \u0000frame was proposed based on static analysis. The present study will help \u0000engineers to design overhead sign support bridges by ensuring both public \u0000safety and structural integrity.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127099616","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 : 2020-01-13DOI: 10.4236/ojce.2020.101004
T. Hromadka, P. Rao, M. Battoei
Effectively managing floods in urban regions requires effectively designed and well-maintained runoff collection system. The absence of such a system and intense rainfall event will have the potential to disrupt the urban life and cause significant economic loss to properties. Grated inlets, which are a key component in urban drainage network, are used to capture the runoff. In this work, a three dimensional CFD model was developed based on open-source CFD tool, OpenFOAM®, to model flow over a grated inlet. An incompressible, transient, multiphase flow, Volume of Fluid (VOF) simulation was performed to predict the water flow rate through the grate inlet. The predicted flow rates are compared with the HEC-22 monograph values. The close agreement between the results shows the potential of using CFD modeling approach to test the reliability of existing drainage inlets for different flow scenarios.
{"title":"CFD Analysis of Flow in a Grated Inlet","authors":"T. Hromadka, P. Rao, M. Battoei","doi":"10.4236/ojce.2020.101004","DOIUrl":"https://doi.org/10.4236/ojce.2020.101004","url":null,"abstract":"Effectively \u0000managing floods in urban regions requires effectively designed and \u0000well-maintained runoff collection system. The absence of such a system and \u0000intense rainfall event will have the potential to disrupt the urban life and \u0000cause significant economic loss to properties. Grated inlets, which are a key \u0000component in urban drainage network, are used to capture the runoff. In this \u0000work, a three dimensional CFD model was developed based on open-source CFD tool, \u0000OpenFOAM®, to model flow over a grated inlet. An incompressible, \u0000transient, multiphase flow, Volume of Fluid (VOF) simulation was performed to \u0000predict the water flow rate through the grate inlet. The predicted flow rates \u0000are compared with the HEC-22 monograph values. The close agreement between the \u0000results shows the potential of using CFD modeling approach to test the \u0000reliability of existing drainage inlets for different flow scenarios.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132249542","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 : 2020-01-13DOI: 10.4236/ojce.2020.101003
Séverin Jean Maixent Loubouth, L. Ahouet, R. Elenga, Sylvain Ndinga Okina, Paul Louzolo Kimbembe
This work consisted in determining the geotechnical properties of the soil of the Cubitermes termite mound soil treated with lime for use in road construction in accordance with the relevant standards. The raw soil is composed of 29.45% clay, 45.12% silt and 25.43% sand, and its granulometric curve is above the relevant standard curve. The addition of lime up to 9% decreases the fine fraction content from 75% to 60%, and the maximum dry density from 1.62 t/m3 to 1.36 t/m3. The reduction of the fine fraction should reduce the soil sensitivity to water, and the emission of dust from the road. The compressive strength of the raw soil (3.89 MPa) is higher than that of most cohesive soil, and is probably one the causes of the longevity of the rural road paved with this soil. Treated soil with 6% in lime content has the highest compressive strength (5.95 MPa), and the lowest deformation at failure. Until 28 days, the improvement of the compressive upon the curing time is almost the same for untreated and treated termite mound soils. Thus, this improvement could be mostly attributed to the drying of the samples instead to the pozzolanic reactions. Besides, adding lime also enhances the shear strength of soil. Therefore, adding lime up to 6% in content to the termite mound soil should improve its behavior as surface roads.
{"title":"Improvement of the Geotechnical Properties of the Soil of Lime-Treated Cubitermes Mound Soil","authors":"Séverin Jean Maixent Loubouth, L. Ahouet, R. Elenga, Sylvain Ndinga Okina, Paul Louzolo Kimbembe","doi":"10.4236/ojce.2020.101003","DOIUrl":"https://doi.org/10.4236/ojce.2020.101003","url":null,"abstract":"This work consisted in determining the geotechnical properties of the \u0000soil of the Cubitermes termite mound soil treated with lime for use in \u0000road construction in accordance with the relevant standards. The raw soil is \u0000composed of 29.45% clay, 45.12% silt and 25.43% sand, and its granulometric curve is above the relevant standard curve. \u0000The addition of lime up to 9% decreases the fine fraction content from 75% to \u000060%, and the maximum dry density from 1.62 t/m3 to 1.36 t/m3. \u0000The reduction of the fine fraction should reduce the soil sensitivity to water, \u0000and the emission of dust from the road. The compressive strength of the raw \u0000soil (3.89 MPa) is higher than that of most cohesive soil, and is probably one the causes of the longevity of the rural \u0000road paved with this soil. Treated soil with 6% in lime content has the highest \u0000compressive strength (5.95 MPa), and the lowest deformation at failure. Until \u000028 days, the improvement of the compressive upon the curing time is almost the \u0000same for untreated and treated termite mound soils. Thus, this improvement could \u0000be mostly attributed to the drying of the samples instead to the pozzolanic reactions. Besides, adding \u0000lime also enhances the shear strength of soil. \u0000Therefore, adding lime up to 6% in content to the termite mound soil should \u0000improve its behavior as surface roads.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"8 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124363286","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 : 2020-01-13DOI: 10.4236/ojce.2020.101006
R. Kassa, T. Workie, Alyu Abdela, Mikiyas Fekade, M. Saleh, Yonas Dejene
Expansive clay soils are the types of soils whose volume changes with the change in water content. They have a behavior of swelling and shrinking that is a serious hazard to structures built over them. Expansive soils are abundantly existing soil types in Ethiopia, particularly Addis Ababa. This paper shows the outcomes of an attempt to reinforce and stabilize expansive clay soil with plastic bottle strips. The plastic strips were prepared and added at three different mixing ratios (0.5%, 1% and 2%) by weight and in three different aspect ratios (5 mm × 7.5 mm, 10 mm × 15 mm, 15 mm × 20 mm). The experimental results showed that there was a significant improvement in shear strength parameters. The swelling and desiccation cracking behavior of the soil were also expressively reduced. There was a substantial reduction in the optimum moisture content and slight increment in maximum dry density. The optimum plastic size (aspect ratio) and plastic content that results in optimum result can be selected based on the importance of the selection parameter for a specified engineering work. Stabilizing expansive clay soils with waste plastic bottles simultaneously solves the challenges of improper plastic waste recycling that is currently a teething problem in most developing countries. The results obtained from this study favorably suggest that inclusion of this material in expansive soils would be effective for ground improvement in geotechnical engineering.
膨胀粘土是一种体积随含水量变化而变化的土。它们有一种膨胀和收缩的行为，这对建在它们上面的结构是一个严重的危害。膨胀土是埃塞俄比亚大量存在的土壤类型，特别是亚的斯亚贝巴。本文介绍了用塑料瓶条加固和稳定膨胀粘土的试验结果。制备并添加3种不同重量混合比(0.5%、1%和2%)和3种不同长宽比(5 mm × 7.5 mm、10 mm × 15 mm、15 mm × 20 mm)的塑料条。试验结果表明，抗剪强度参数有明显改善。土壤的膨胀和干燥开裂行为也明显降低。最佳含水率显著降低，最大干密度略有增加。根据具体工程选择参数的重要程度，可以选择产生最佳效果的最佳塑性尺寸(长宽比)和塑性含量。用废塑料瓶稳定膨胀粘土同时解决了塑料废物回收不当的挑战，这是目前大多数发展中国家的一个初期问题。本研究的结果表明，在膨胀土中加入这种材料对岩土工程中的地基改善是有效的。
{"title":"Soil Stabilization Using Waste Plastic Materials","authors":"R. Kassa, T. Workie, Alyu Abdela, Mikiyas Fekade, M. Saleh, Yonas Dejene","doi":"10.4236/ojce.2020.101006","DOIUrl":"https://doi.org/10.4236/ojce.2020.101006","url":null,"abstract":"Expansive clay soils are the types of soils whose \u0000volume changes with the change in water content. They have a behavior of \u0000swelling and shrinking that is a serious hazard to structures built over them. \u0000Expansive soils are abundantly existing soil types in Ethiopia, particularly \u0000Addis Ababa. This paper shows the outcomes of an attempt to reinforce and \u0000stabilize expansive clay soil with plastic bottle strips. The plastic strips \u0000were prepared and added at three different mixing ratios (0.5%, 1% and 2%) by \u0000weight and in three different aspect ratios (5 mm × 7.5 mm, 10 mm × 15 mm, 15 mm \u0000× 20 mm). The experimental results showed that there was a significant \u0000improvement in shear strength parameters. The swelling and desiccation cracking \u0000behavior of the soil were also expressively reduced. There was a substantial \u0000reduction in the optimum moisture content and slight increment in maximum dry \u0000density. The optimum plastic size (aspect ratio) and plastic content that \u0000results in optimum result can be selected based on the importance of the \u0000selection parameter for a specified engineering work. Stabilizing expansive \u0000clay soils with waste plastic bottles simultaneously solves the challenges of \u0000improper plastic waste recycling that is currently a teething problem in most \u0000developing countries. The results obtained from this study favorably suggest \u0000that inclusion of this material in expansive soils would be effective for \u0000ground improvement in geotechnical engineering.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130935905","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 : 2020-01-13DOI: 10.4236/ojce.2020.101007
Kossi Bolanigni Amey
This study aims at analyzing the repartition of the quantities of shells of sand sediments of Togolese littoral, and at determining the law underlying their longitudinal and transversal distributions. Samples (210), collected all along Togolese littoral starting from Togo-Ghana border up to Togo-Benin border, are subject to the test of sieving. Each refusal on sieve is tested against construction of shells by hydrochloric acid. The determination of the quantity of shells according to their size and to longitudinal and transversal distributions on the littoral is completed. As a conclusion, the quantity of shells in the sediments is getting lower and lower starting from the aerial mid-beach (14.2%) to the mid-foreshore (11.80%), and getting higher and higher from the mid-foreshore (11.80%) to the low-foreshore (13.32%). It is getting lower and lower according to the direction of sediments’ transportations. This quantity of shells is high (40.87%) in the fine-grained sands (Ø Ø > 2 mm) and low (>24.26%) in the average-grained sands (0.125 mm ≤ Ø ≤ 2 mm). The average quantity of shells of 12.67% is lower than the recommended maximum quantity (30%) for the sands used for concrete. Thus, for the concrete works, the littoral sands might be seen as useful since they are granulating for concrete.
{"title":"Law of Distribution of Quantities of Shells on Togolese Littoral","authors":"Kossi Bolanigni Amey","doi":"10.4236/ojce.2020.101007","DOIUrl":"https://doi.org/10.4236/ojce.2020.101007","url":null,"abstract":"This study aims at analyzing the repartition of the quantities of shells \u0000of sand sediments of Togolese littoral, and at determining the law underlying \u0000their longitudinal and transversal distributions. Samples (210), collected all \u0000along Togolese littoral starting from Togo-Ghana border up to Togo-Benin border, \u0000are subject to the test of sieving. Each refusal on sieve is tested against \u0000construction of shells by hydrochloric acid. The determination of the quantity \u0000of shells according to their size and to longitudinal and transversal \u0000distributions on the littoral is completed. As a conclusion, the quantity of \u0000shells in the sediments is getting lower and lower starting from the aerial \u0000mid-beach (14.2%) to the mid-foreshore (11.80%), and getting higher and higher \u0000from the mid-foreshore (11.80%) to the low-foreshore (13.32%). It is getting \u0000lower and lower according to the direction of sediments’ transportations. This \u0000quantity of shells is high (40.87%) in the fine-grained sands (Ø Ø > 2 mm) and low (>24.26%) in the average-grained sands (0.125 mm ≤ Ø ≤ 2 mm). The average quantity of shells of 12.67% is lower than the \u0000recommended maximum quantity (30%) for the sands used for concrete. Thus, for \u0000the concrete works, the littoral sands might be seen as useful since they are granulating \u0000for concrete.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122067044","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 : 2020-01-13DOI: 10.4236/ojce.2020.101005
Zhenzhen Wang, Y. Lou, Benxiao Zhang, Bin Shi
At present and for a long time in the future, urbanization in China will maintain a rapid development speed. After the rainstorm, the phenomenon of “sea views” is common. The direct reason is that the urban drainage system and the ground drainage system cannot afford the large flow of water in a short period of time, but the most fundamental reason is that the artificial construction environment changes the water storage and drainage function of the ground under the natural state. “Sponge city construction” came into being. This paper mainly analyzes and studies the sponge city construction in Pingxiang City, Jiangxi Province, and uses the method of field investigation and literature data to clarify the ideas of the sponge city construction in Pingxiang City and summarize the successful experience, which can provide a reference for the subsequent “sponge city development” ideas.
{"title":"Thoughts and Strategies of Sponge City Construction Planning: A Case Study of Pingxiang, Jiangxi Province","authors":"Zhenzhen Wang, Y. Lou, Benxiao Zhang, Bin Shi","doi":"10.4236/ojce.2020.101005","DOIUrl":"https://doi.org/10.4236/ojce.2020.101005","url":null,"abstract":"At \u0000present and for a long time in the future, urbanization in China will maintain \u0000a rapid development speed. After the rainstorm, the phenomenon of “sea views” \u0000is common. The direct reason is that the urban drainage system and the ground \u0000drainage system cannot afford the large flow of water in a short period of time, \u0000but the most fundamental reason is that the artificial construction environment \u0000changes the water storage and drainage function of the ground under the natural \u0000state. “Sponge city construction” came into being. This paper mainly analyzes and studies the sponge city \u0000construction in Pingxiang City, Jiangxi Province, and uses the method of field \u0000investigation and literature data to clarify the ideas of the sponge city \u0000construction in Pingxiang City and summarize the successful experience, which \u0000can provide a reference for the subsequent “sponge city development” ideas.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126201917","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}
Kong-liang Chen, G. Yuan, L. Wang, Wen-zhong Zhang, Xiaoke Wang
The steel roof of Jiangmen gymnasium is the large-span spatial pipe truss structure, which is composed of main truss, secondary truss and stable truss. This paper systematically expounds the construction simulation analysis, the composition of the construction monitoring system, the monitoring method, and the arrangement of measuring points. The construction simulation analysis simulates the whole process of the main truss cumulative lifting installation, the secondary truss and auxiliary structure hoisting, and then the main truss for overall unloading, which is the difficulty of the whole project. The results of the structural construction monitoring show that the roof structure is in a safe state, and the fine construction simulation analysis provides a theoretical basis for the construction process, and the theoretical value of the simulation analysis is in good agreement with the measured data. In addition, vertical displacement and stress are obvious mutations in the unloading stage of roof support, but the stress of each measuring point is in elastic working condition, which meets the design requirements, indicating the correctness of the model and method in construction simulation analysis and calculation, and also provides reference for the design and construction of related projects in the future.
{"title":"Research on Construction Monitoring of Large-Span Steel Pipe Truss Structure","authors":"Kong-liang Chen, G. Yuan, L. Wang, Wen-zhong Zhang, Xiaoke Wang","doi":"10.4236/ojce.2019.94018","DOIUrl":"https://doi.org/10.4236/ojce.2019.94018","url":null,"abstract":"The steel roof of Jiangmen gymnasium is the large-span \u0000spatial pipe truss structure, which is composed of main truss, secondary truss and stable truss. This paper systematically \u0000expounds the construction simulation \u0000analysis, the composition of the construction monitoring system, the monitoring \u0000method, and the arrangement of measuring points. The construction simulation \u0000analysis simulates the whole process of the main truss cumulative lifting \u0000installation, the secondary truss and \u0000auxiliary structure hoisting, and then the main truss for overall unloading, \u0000which is the difficulty of the whole project. The results of the structural \u0000construction monitoring show that the roof structure is in a safe state, and \u0000the fine construction simulation analysis provides a theoretical basis for the \u0000construction process, and the theoretical value of the simulation analysis is \u0000in good agreement with the measured data. In addition, vertical displacement \u0000and stress are obvious mutations in the unloading stage of \u0000roof support, but the stress of each measuring point is in elastic working \u0000condition, which meets the design requirements, indicating the correctness of \u0000the model and method in construction simulation analysis and calculation, and \u0000also provides reference for the design and construction of related projects in the \u0000future.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133266490","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}
The dry-separation method is an alternative to the wet-preparation in the current European Standard for the determination of particle size distributions by the sieving of soils. Due to the risk of error, dry-separation is cautioned against in the standard; however, there is no additional guidance as to when it is unsuitable nor for the magnitude of error that it may introduce. This study investigates the dry-separation method as an alternative by comparing with the conventional method of Wet-preparation in terms of particle-size distributions of eight cohesionless sand-gravel soils with varying amounts of nonplastic fines. The findings indicate a gradually increasing sieving error for fractions at minus 0.5 mm with the amount of fines in the soil, and depending on the fines content of the soil, dry-separation introduced errors upwards of 45% in silt-sand-gravel soils. An empirical best-fit formula is proposed for the estimation of the error using the dry-preparation method on this type of soil. Furthermore, to avoid sieving errors, the results suggest that the dry-separation method should not be used for silt-sand-gravel soils exceeding 2% silt size fractions.
{"title":"Sieving Error from Dry-Separating Silt-Sand-Gravel Soils","authors":"H. Rönnqvist","doi":"10.4236/ojce.2019.94022","DOIUrl":"https://doi.org/10.4236/ojce.2019.94022","url":null,"abstract":"The dry-separation method is an alternative to the wet-preparation in the \u0000current European Standard for the determination of particle size distributions \u0000by the sieving of soils. Due to the risk of error, dry-separation is cautioned \u0000against in the standard; however, there is no additional guidance as to when it \u0000is unsuitable nor for the magnitude of error that it may introduce. This study \u0000investigates the dry-separation method as an alternative by comparing with the conventional method of Wet-preparation in terms of particle-size distributions of eight cohesionless sand-gravel \u0000soils with varying amounts of nonplastic fines. The findings indicate a \u0000gradually increasing sieving error for fractions at minus 0.5 mm with the amount of fines in the \u0000soil, and depending on the fines content of the soil, dry-separation introduced \u0000errors upwards of 45% in silt-sand-gravel soils. An \u0000empirical best-fit formula is proposed for the \u0000estimation of the error using the dry-preparation method on this type of soil. \u0000Furthermore, to avoid sieving errors, the results suggest that the dry-separation method should not be used for silt-sand-gravel \u0000soils exceeding 2% silt size fractions.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128748853","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}
The Earthquake can be considered as a natural phenomenon or a disaster based on the seismic response of structures during a severe earthquake that plays a vital role in the extent of structural damage and resulting injuries and losses. It is necessary to predict the performance of the existing structures and structures at the design stage when it subjected to an earthquake load. Also, it is needed to predict the repair cost required for the rehabilitation of the existing buildings that is insufficient in seismic resistance, and the construction cost and the expected repairing cost for the structures at the design stage that designed to have a ductile behavior with acceptable cracks. This study aims to propose a method for seismic performance evaluation for existing and new structures depending on the width of cracks resulted from the seismic exposure. Also, it assesses the effect of building performance during earthquakes on its life cycle cost. FEMA 356 criteria were used to predict the building responses due to seismic hazard. A case study of seven-story reinforced concrete building designed by four design approaches and then analyzed by static nonlinear pushover analysis to predict its response and performance during earthquake events using Sap 2000 software. The first design approach is to design the building to resist gravity loads only by using ECP code. The second one is to design the building to resist gravity loads and seismic loads by using static linear analysis according to ECP code. The third one is to design the building to resist gravity loads and seismic loads by using static linear analysis according to the regulations of the Egyptian Society of Earthquake Engineering (ESEE). Finally the fourth one is to design the building as the second approach but with ground acceleration greater by five times than it or by using ductility factor R = 1. The methodology followed in this study provides initial guidelines, and steps required to assess the seismic performance and the cost associated with using a variety of design methods for reinforced concrete structures resisting earthquakes, selecting the retrofitting strategies that would be indicated to repair the structure after an earthquake.
{"title":"Proposed Method for Cost Assessment of Seismic Mitigation Designs for Reinforced Concrete Buildings According to ECP Code","authors":"Yasser Fayed, M. Sobaih, Yasser El Hakem","doi":"10.4236/ojce.2019.94023","DOIUrl":"https://doi.org/10.4236/ojce.2019.94023","url":null,"abstract":"The Earthquake can be considered as a natural phenomenon or a disaster \u0000based on the seismic response of structures during a severe earthquake that \u0000plays a vital role in the extent of structural damage and resulting injuries \u0000and losses. It is necessary to predict the performance of the existing structures \u0000and structures at the design stage when it subjected to an earthquake load. \u0000Also, it is needed to predict the repair cost required for the rehabilitation \u0000of the existing buildings that is insufficient in seismic resistance, and the \u0000construction cost and the expected repairing cost for the structures at the \u0000design stage that designed to have a ductile behavior with acceptable cracks. \u0000This study aims to propose a method for seismic performance evaluation for existing and new structures depending on the \u0000width of cracks resulted from the seismic exposure. Also, it assesses the effect of building performance during \u0000earthquakes on its life cycle cost. FEMA 356 criteria were used to predict the \u0000building responses due to seismic hazard. A case study of seven-story reinforced concrete building \u0000designed by four design approaches and then analyzed by static nonlinear \u0000pushover analysis to predict its response and performance during earthquake events using Sap 2000 software. The \u0000first design approach is to design the building to resist gravity loads only by \u0000using ECP code. The second one is to design the building to resist gravity \u0000loads and seismic loads by using static linear analysis according to ECP code. \u0000The third one is to design the building to resist gravity loads and seismic \u0000loads by using static linear analysis according to the regulations of the \u0000Egyptian Society of Earthquake Engineering (ESEE). Finally the fourth one is to design the building as the second approach \u0000but with ground acceleration greater by \u0000five times than it or by using ductility factor R = 1. The \u0000methodology followed in this study provides initial guidelines, and steps \u0000required to assess the seismic performance and the cost associated with using a \u0000variety of design methods for reinforced concrete structures resisting earthquakes, selecting \u0000the retrofitting strategies that would be indicated to repair the structure \u0000after an earthquake.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126488753","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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