For soil improvement, a method using plant fiber has been used since ancient times. In recent years, the construction method using plant fiber has attracted attention as a ground improvement technology with less environmental load. In this work, the soil improvement effect using waste bamboo fiber was experimentally examined. The liquid limit and plastic limit of the mixed soil tended to increase with increasing bamboo fiber content and there was no change in the plasticity index of the mixed soil by the difference of bamboo fiber content. As a result from the compaction test and unconfined compression test, it was revealed that mixing of bamboo fiber resulted in a reduction of soil material required for construction and increasing in strength. The maximum compressive stress of the bamboo fiber mixed soil at the mixing ratio of 0%, 1%, 3% and 5% were 115, 108, 130 and 152 kN/m2, respectively. As the soil with fiber showed the lower stiffness and higher strength than that without fiber in the dry region, it can be judged that the addition of fiber brought ductility to the soil. And it was found that the decrease in the stiffness of the specimen due to the increase of water content was suppressed by the addition of the bamboo fiber. From the results of the observation with the digital microscope, it was observed that the two-layer structure consisting of the main relatively thick fibrous structure and the secondary capillary fibrous structure were formed. Thus, it was found that the complex structure of the bamboo fiber is deeply involved in the strength of the mixed soil.
{"title":"Effect of Waste Bamboo Fiber Addition on Mechanical Properties of Soil","authors":"Motohei Kanayama, S. Kawamura","doi":"10.4236/OJCE.2019.93012","DOIUrl":"https://doi.org/10.4236/OJCE.2019.93012","url":null,"abstract":"For soil improvement, a method using plant fiber has been used since ancient times. In recent years, the construction method using plant fiber has attracted attention as a ground improvement technology with less environmental load. In this work, the soil improvement effect using waste bamboo fiber was experimentally examined. The liquid limit and plastic limit of the mixed soil tended to increase with increasing bamboo fiber content and there was no change in the plasticity index of the mixed soil by the difference of bamboo fiber content. As a result from the compaction test and unconfined compression test, it was revealed that mixing of bamboo fiber resulted in a reduction of soil material required for construction and increasing in strength. The maximum compressive stress of the bamboo fiber mixed soil at the mixing ratio of 0%, 1%, 3% and 5% were 115, 108, 130 and 152 kN/m2, respectively. As the soil with fiber showed the lower stiffness and higher strength than that without fiber in the dry region, it can be judged that the addition of fiber brought ductility to the soil. And it was found that the decrease in the stiffness of the specimen due to the increase of water content was suppressed by the addition of the bamboo fiber. From the results of the observation with the digital microscope, it was observed that the two-layer structure consisting of the main relatively thick fibrous structure and the secondary capillary fibrous structure were formed. Thus, it was found that the complex structure of the bamboo fiber is deeply involved in the strength of the mixed soil.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133463245","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}
A new method for analysis of counter beams is presented in the paper. The analysis has taken into account their stiffness EI, Winkler’s space with modulus of subgrade reaction k and equality deformities of the foundation beam with the ground. The solution is found by using the numerical analysis of the Winkler’s model, with variation of different moduli of the subgrade reaction k2 outside the force zone r, while under the force P exists the modulus of the subgrade reaction k, up to the definition of minimum bending moments. The exponential function k2(r), as the geometric position of the minimum moments is approximately assumed. From the potential energy conditions of the reciprocity of displacement and reaction, the width of the zone r and the modulus of the subgrade reaction k2 are explicitly determined, introducing in the calculation initial and calculation soil displacement wsi successively. At the end of the paper, it presented numerical example in which the influence of k and k2 values on bending moments of the counter beam is analyzed. The essential idea of this paper is to decrease the quantity of the reinforcement in the foundations, beams, i.e. to obtain a cost-efficient foundation construction.
{"title":"Bending the Foundation Beam on Elastic Base by Two Reaction Coefficient of Winkler’s Subgrade","authors":"M. Balabušić, B. Folić, Slobodan Ćorić","doi":"10.4236/OJCE.2019.92009","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92009","url":null,"abstract":"A new method for analysis of counter beams is presented in the paper. The analysis has taken into account their stiffness EI, Winkler’s space with modulus of subgrade reaction k and equality deformities of the foundation beam with the ground. The solution is found by using the numerical analysis of the Winkler’s model, with variation of different moduli of the subgrade reaction k2 outside the force zone r, while under the force P exists the modulus of the subgrade reaction k, up to the definition of minimum bending moments. The exponential function k2(r), as the geometric position of the minimum moments is approximately assumed. From the potential energy conditions of the reciprocity of displacement and reaction, the width of the zone r and the modulus of the subgrade reaction k2 are explicitly determined, introducing in the calculation initial and calculation soil displacement wsi successively. At the end of the paper, it presented numerical example in which the influence of k and k2 values on bending moments of the counter beam is analyzed. The essential idea of this paper is to decrease the quantity of the reinforcement in the foundations, beams, i.e. to obtain a cost-efficient foundation construction.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132663881","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 design and construction of tall and slender steel structures is always challenging. This paper discusses several design aspects (structural information, analysis methods, applied loads, cost optimisation) and a case study regarding the design and construction of 10-m-tall windbreak panels for a Greek electricity producer. The purpose of the panels is to reduce wind turbulence and improve the performance of the electricity producer’s air-cooled condenser. In this case, the main wind load acts in the longitudinal direction, with friction inducing only a small amount of wind load in the transverse direction. The steel columns are constructed from 10-m-tall hot-rolled IPE 270 (S235) cross-sections, and are supported by cables in the longitudinal direction and bracing systems in the transverse direction. Concrete anchorages and concrete footings are used for the cables and steel columns, respectively. System optimisation is investigated in terms of the steel weight, cable length, and overall cost, and practical issues are explained regarding technical decisions. Furthermore, the construction details, construction methods, and cost estimation are discussed.
{"title":"Design of Tall Cable-Supported Windbreak Panels","authors":"Chrysanthos Maraveas","doi":"10.4236/OJCE.2019.92008","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92008","url":null,"abstract":"The design and construction of tall and slender steel structures is always challenging. This paper discusses several design aspects (structural information, analysis methods, applied loads, cost optimisation) and a case study regarding the design and construction of 10-m-tall windbreak panels for a Greek electricity producer. The purpose of the panels is to reduce wind turbulence and improve the performance of the electricity producer’s air-cooled condenser. In this case, the main wind load acts in the longitudinal direction, with friction inducing only a small amount of wind load in the transverse direction. The steel columns are constructed from 10-m-tall hot-rolled IPE 270 (S235) cross-sections, and are supported by cables in the longitudinal direction and bracing systems in the transverse direction. Concrete anchorages and concrete footings are used for the cables and steel columns, respectively. System optimisation is investigated in terms of the steel weight, cable length, and overall cost, and practical issues are explained regarding technical decisions. Furthermore, the construction details, construction methods, and cost estimation are discussed.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115324265","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}
Concrete properties can be improved using Fine Blast Furnace Slag (BFS). The latter was used to replace cement in concrete at 10%, 15%, 20%, 25%, and 30% proportions and properties of both fresh and hardened concrete improved. Best workability (evaluated by slump and Table tests) was recorded at 30% of BFS addition. VEBE-time, an indication of workability of concrete, decreased to its lowest value (about 4 seconds at 30% BFS) and compaction factor attained its maximum value of 99% at BFS 25%. For density and unit weight, 30% of fine BFS in concrete mix resulted in maximum density of 2180 kg/m3 for fresh concrete, and 2430 kg/m3 for hardened concrete. Unit weight of concrete achieved a maximum of 23.9 kN/m3 at 30% BFS has achieved specified strength at 1st week and 28 days, also the late strength is high at 56 and 84 days. Bond and flexure loads come high of BFS use. The data of compressive, bond, and flexural strengths are highly related. Results of research are useful and may be applied using fine BFS to improve the properties of concrete materials.
{"title":"The Use of Fine Blast Furnace Slag in Improvement of Properties of Concrete","authors":"H. Al-Baijat, Mohmd Sarireh","doi":"10.4236/OJCE.2019.92007","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92007","url":null,"abstract":"Concrete properties can be improved using Fine Blast Furnace Slag (BFS). The latter was used to replace cement in concrete at 10%, 15%, 20%, 25%, and 30% proportions and properties of both fresh and hardened concrete improved. Best workability (evaluated by slump and Table tests) was recorded at 30% of BFS addition. VEBE-time, an indication of workability of concrete, decreased to its lowest value (about 4 seconds at 30% BFS) and compaction factor attained its maximum value of 99% at BFS 25%. For density and unit weight, 30% of fine BFS in concrete mix resulted in maximum density of 2180 kg/m3 for fresh concrete, and 2430 kg/m3 for hardened concrete. Unit weight of concrete achieved a maximum of 23.9 kN/m3 at 30% BFS has achieved specified strength at 1st week and 28 days, also the late strength is high at 56 and 84 days. Bond and flexure loads come high of BFS use. The data of compressive, bond, and flexural strengths are highly related. Results of research are useful and may be applied using fine BFS to improve the properties of concrete materials.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124995812","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}
Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the resource of aggregate. The properties of aggregate and fine sand were studied (specific gravity, density, absorption, and abrasion). Also, the properties of concrete were studied (density, unit weight, and compressive strength). Samples of coarse and medium aggregates, and fine sand were collected from different areas in Jordan (Ajloun, Amman, Aqaba, Irbid, Jerash, Karak, Ma’an, Madaba, Salt, Zarqa, and Tafila) to be tested and used in concrete mix. Aggregate from South of Jordan has higher values in specific gravity and bulk density (Aqaba, Ma’an, and Karak aggregates). Also, the same aggregate samples have lower values in absorption and abrasion (Ma’an, Aqaba, Karak, and Tafila). For the properties of concrete that include density, unit weight, and compressive strength, all samples have achieved the design properties and strength in the current study. For density and unit weight, samples from South of Jordan have higher values (Ma’an and Aqaba). And for compressive strength, Ma’an, Irbid and Amman concrete samples have the highest values at 7-day, while the 28-day compressive strength comes highest for Zarqa, Ma’an, Irbid and Amman. From the results of the current study, the compressive strength at 7-day and 28-day is related to the density of coarse and medium aggregate, abrasion, and absorption. The higher the density, the higher the compressive strength. And the lower abrasion and absorption, the higher the compressive strength of concrete. Current research will be useful in selecting the source of aggregate to produce a considerable concrete strength.
{"title":"Local Aggregate in Production of Concrete Mix in Jordan","authors":"Mohmd Sarireh, H. Al-Baijat","doi":"10.4236/OJCE.2019.92006","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92006","url":null,"abstract":"Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the resource of aggregate. The properties of aggregate and fine sand were studied (specific gravity, density, absorption, and abrasion). Also, the properties of concrete were studied (density, unit weight, and compressive strength). Samples of coarse and medium aggregates, and fine sand were collected from different areas in Jordan (Ajloun, Amman, Aqaba, Irbid, Jerash, Karak, Ma’an, Madaba, Salt, Zarqa, and Tafila) to be tested and used in concrete mix. Aggregate from South of Jordan has higher values in specific gravity and bulk density (Aqaba, Ma’an, and Karak aggregates). Also, the same aggregate samples have lower values in absorption and abrasion (Ma’an, Aqaba, Karak, and Tafila). For the properties of concrete that include density, unit weight, and compressive strength, all samples have achieved the design properties and strength in the current study. For density and unit weight, samples from South of Jordan have higher values (Ma’an and Aqaba). And for compressive strength, Ma’an, Irbid and Amman concrete samples have the highest values at 7-day, while the 28-day compressive strength comes highest for Zarqa, Ma’an, Irbid and Amman. From the results of the current study, the compressive strength at 7-day and 28-day is related to the density of coarse and medium aggregate, abrasion, and absorption. The higher the density, the higher the compressive strength. And the lower abrasion and absorption, the higher the compressive strength of concrete. Current research will be useful in selecting the source of aggregate to produce a considerable concrete strength.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124744452","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}
Delphine, P. Witte, T. Hartmann, T. Spit, A. Zoomers
Investing in large transport projects affects the (potential) economic development of metropolitan areas. Yet, very little critical research has been performed to understand how to assess these effects. The relationship between infrastructure investments and regional economic development is complex and indirect, and many theoretical and methodological difficulties remain. On the one hand, the assumption that investing in infrastructure is important to sustain economic growth is sometimes doubted. On the other hand, it is argued that investments in infrastructure enhance the accessibility of urban regions and that in the slipstream of such investments, social problems in urban regions can be tackled as well. Despite these contrasting views, there is at least a consensus that transport infrastructure development depends on economic development and vice versa. Yet, in many cases, the method of assessing economic impacts highly affects the results. Therefore, this paper focuses on a critical reflection of methods for estimating economic effects of infrastructure investments. A critical evaluation is made based on Indonesian and Japanese cases. After conducting in-depth desk research on both cases, we found that the broader effects on affected group of people tend to be overlooked due to the problems of time and space dimensions, the chain reaction of effects, and inappropriate data practices. The assessment on the appraisal processes tends to overlook the broader economic implication due to narrow focus and the concept of efficiency of economic theory.
{"title":"For the Greater Good?—A Critical Reflection on Assessing Indirect Economic Effects Caused by Large Transport Projects","authors":"Delphine, P. Witte, T. Hartmann, T. Spit, A. Zoomers","doi":"10.4236/OJCE.2019.92010","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92010","url":null,"abstract":"Investing in large transport projects affects the (potential) economic development of metropolitan areas. Yet, very little critical research has been performed to understand how to assess these effects. The relationship between infrastructure investments and regional economic development is complex and indirect, and many theoretical and methodological difficulties remain. On the one hand, the assumption that investing in infrastructure is important to sustain economic growth is sometimes doubted. On the other hand, it is argued that investments in infrastructure enhance the accessibility of urban regions and that in the slipstream of such investments, social problems in urban regions can be tackled as well. Despite these contrasting views, there is at least a consensus that transport infrastructure development depends on economic development and vice versa. Yet, in many cases, the method of assessing economic impacts highly affects the results. Therefore, this paper focuses on a critical reflection of methods for estimating economic effects of infrastructure investments. A critical evaluation is made based on Indonesian and Japanese cases. After conducting in-depth desk research on both cases, we found that the broader effects on affected group of people tend to be overlooked due to the problems of time and space dimensions, the chain reaction of effects, and inappropriate data practices. The assessment on the appraisal processes tends to overlook the broader economic implication due to narrow focus and the concept of efficiency of economic theory.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"326 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123094347","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 estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 - 0.53 for sand soil slope, 0.46 - 0.55 for silt soil slope and 0.42 - 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.
{"title":"Experimental Study of Runoff Coefficients for Different Hill Slope Soil Profiles","authors":"D. Khadka","doi":"10.4236/OJCE.2019.92011","DOIUrl":"https://doi.org/10.4236/OJCE.2019.92011","url":null,"abstract":"The estimation of peak discharge from a catchment due to intense rainfall is a difficult task that may occur in a return period. If cannot be estimated accurately, it may lead to serious problem in hydraulic structure design like bridge, culvert across a river and drainage system. The main parameter which affects the peak flow is runoff coefficient of the catchment which directly depends on the soil type, its slope and land use pattern with vegetation covers. For the purpose, this study was carried out to estimate maximum runoff coefficients for different land profiles and soil types in hill slope model developed in 10 degree with the horizontal to the rainfall simulator rig (Basic Hydrology system-S12) experimentally which can give more reliable value than the real field test method as it is easier than field test especially in hill slope. The soil slope preparation was made of sand, silt and clay separately and the experiments were carried out in a controlled system. The slope prepared represented a small catchment on a plot of 2.02 meter length, 1 meter wide and 0.15 m depth soil plots (at the slope of 10° to the horizontal plane). From the experiment in different soil plots, the rainfall runoff coefficients were observed as 0.428 - 0.53 for sand soil slope, 0.46 - 0.55 for silt soil slope and 0.42 - 0.51 for clay soil slope under uniform rainfall rate of 4 lpm to 13 lpm in each soil slope. Rainfall runoff correlation equation was found with the values of R above 90% in each soil slope. The value observed is within the range of rational value of 0.05 to 0.95 as standard which concluded that the performance of simulator was found good to deal with rational values. And the runoff coefficients for these soil types can be taken within the range obtained to estimate peak discharge in any small catchment area depending on the soil types.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131277950","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}
N. Malanda, P. Louzolo-Kimbémbé, L. Ahouet, Jarlon Brunel Makela, G. Mouengue
The present work consisted in carrying out a study on the effective formulation of concrete for an optimal resistance to compression (fc28) between 20 and 30 MPa for the sites animated by the actors of the informal and semi-informal sectors of the construction. Studies have been carried out on projects under construction, by taking samples of fresh concrete in order to evaluate their real compressive strengths. These surveys show that there is a problem in the concrete formulation, as nearly 2/3 of the results show the lack of technical knowledge on concrete formulation practices. Indeed, on eight sites surveyed and whose fresh concrete samples were taken, only two sites (7 and 8) report fairly consistent results. Their 28-day compressive strength values are respectively 35.36 and 22.18 MPa. In addition, various formulations proposed with aggregates from different quarries or extracts from the bed of the Congo River, were determined in the laboratory. This study allowed us to obtain fairly objective results overall, which is characteristic of concretes of required quality. Of the six (06) formulation proposals, average resistances of 19.6 MPa at 07 days and 25.28 MPa at 28 days were obtained. These results at 28 days are in the range of 20 to 30 MPa, set as objective in this study. These formulations can be a reliable source for concrete manufacturers in these construction sectors. Similarly, the statistical study based on principal component factor analysis tests has shown that the most appropriate formulation, in terms of mechanical resistance, is that proposed with sand extracted from the Congo River (formulation 3). This is justified by the fact that this sand is consistent and has a good granular distribution.
{"title":"Concrete Formulation Study for Informal and Semi-Informal Construction Sectors","authors":"N. Malanda, P. Louzolo-Kimbémbé, L. Ahouet, Jarlon Brunel Makela, G. Mouengue","doi":"10.4236/OJCE.2019.91005","DOIUrl":"https://doi.org/10.4236/OJCE.2019.91005","url":null,"abstract":"The present work consisted in carrying out a study on the effective formulation of concrete for an optimal resistance to compression (fc28) between 20 and 30 MPa for the sites animated by the actors of the informal and semi-informal sectors of the construction. Studies have been carried out on projects under construction, by taking samples of fresh concrete in order to evaluate their real compressive strengths. These surveys show that there is a problem in the concrete formulation, as nearly 2/3 of the results show the lack of technical knowledge on concrete formulation practices. Indeed, on eight sites surveyed and whose fresh concrete samples were taken, only two sites (7 and 8) report fairly consistent results. Their 28-day compressive strength values are respectively 35.36 and 22.18 MPa. In addition, various formulations proposed with aggregates from different quarries or extracts from the bed of the Congo River, were determined in the laboratory. This study allowed us to obtain fairly objective results overall, which is characteristic of concretes of required quality. Of the six (06) formulation proposals, average resistances of 19.6 MPa at 07 days and 25.28 MPa at 28 days were obtained. These results at 28 days are in the range of 20 to 30 MPa, set as objective in this study. These formulations can be a reliable source for concrete manufacturers in these construction sectors. Similarly, the statistical study based on principal component factor analysis tests has shown that the most appropriate formulation, in terms of mechanical resistance, is that proposed with sand extracted from the Congo River (formulation 3). This is justified by the fact that this sand is consistent and has a good granular distribution.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114468350","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}
S. Arhin, A. Gatiba, Melissa F. Anderson, Melkamsew Ribbisso, Babin Manandhar
In this research, a strategy to improve mobility and reduce delay on road segments is explored via modeling and simulation. Thirty selected corridors with combination of signalized and unsignalized intersections were identified for this study. Each segment consists of at least one AWSC and two signalized intersections at which field data were obtained (lane configurations, signal timing, traffic volumes, etc.). The selected AWSC intersections on the segments were within 305 m (1000 feet) from the upstream or downstream signalized intersections. Synchro software program was utilized to model the existing condition of the segments based on which the strategy for mobility improvement was explored. The field data were used as input in Synchro software application to model two scenarios: existing or the “before” scenario, and the “after” scenario. The unsignalized intersections were signalized (and optimized) in the “after” scenario. The measures of effectiveness used to assess the efficiency of the strategy were average travel speed, control delay and 95th percentile queue length. The analyses were conducted for both the morning (AM) and evening (PM) peak periods. The results of the analyses showed reductions in control delay and 95th percentile queue lengths that were statistically significant, while the average travel speed of vehicles significantly increased at 5% level of significance. The evaluation determined that the signalization of some unsignalized intersections (which are 305 m or less from existing signalized intersections) may improve mobility despite the fact that these locations do not meet the MUTCD warrants for signalization. These findings would aid transportation engineers and planners to consider and evaluate this option when making decisions on signalization of intersections in urban areas.
{"title":"Improving Mobility on Segments with Closely Spaced Intersections in Urban Areas","authors":"S. Arhin, A. Gatiba, Melissa F. Anderson, Melkamsew Ribbisso, Babin Manandhar","doi":"10.4236/OJCE.2019.91004","DOIUrl":"https://doi.org/10.4236/OJCE.2019.91004","url":null,"abstract":"In this research, a strategy to improve mobility and reduce delay on road segments is explored via modeling and simulation. Thirty selected corridors with combination of signalized and unsignalized intersections were identified for this study. Each segment consists of at least one AWSC and two signalized intersections at which field data were obtained (lane configurations, signal timing, traffic volumes, etc.). The selected AWSC intersections on the segments were within 305 m (1000 feet) from the upstream or downstream signalized intersections. Synchro software program was utilized to model the existing condition of the segments based on which the strategy for mobility improvement was explored. The field data were used as input in Synchro software application to model two scenarios: existing or the “before” scenario, and the “after” scenario. The unsignalized intersections were signalized (and optimized) in the “after” scenario. The measures of effectiveness used to assess the efficiency of the strategy were average travel speed, control delay and 95th percentile queue length. The analyses were conducted for both the morning (AM) and evening (PM) peak periods. The results of the analyses showed reductions in control delay and 95th percentile queue lengths that were statistically significant, while the average travel speed of vehicles significantly increased at 5% level of significance. The evaluation determined that the signalization of some unsignalized intersections (which are 305 m or less from existing signalized intersections) may improve mobility despite the fact that these locations do not meet the MUTCD warrants for signalization. These findings would aid transportation engineers and planners to consider and evaluate this option when making decisions on signalization of intersections in urban areas.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134556187","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 paper discusses the design, fabrication and the execution of the cladding supported by steel trusses and curtain wall of a sports club. The cladding and the curtain walls were subjected to a wind load of 1.2 Kpa considering basic wind speed of 25 m/s as per the project specifications. The first part of the paper deals with the cladding work of the canopy that consist of a 4 mm thick aluminium composite panels supported by steel trusses extended from the main structure. Two types of steel trusses were provided, the main truss connected to the space truss, whereas the intermediate truss connected to channels. Both trusses were spaced at 2.5 m centre to centre. These trusses were fabricated at factory and transported to the site for installation. The second part of the paper is related to the curtain wall design having Maximum Mullion spacing of 2 m, considered as worst scenario for the design calculations. The maximum Mullion height was 5.55 m, adopted in the calculations with bottom and top pinned connection. The Technal system was adopted for the design of mullions and transoms. Design was carried out using numerical modeling with CSI SAP2000 for cladding and its supporting structures. The bracket was realized and checked for the corresponding induced forces. All the structural systems were found safe according to different acceptance criterion.
{"title":"Design and Fabrication of Aluminum Cladding and Curtain Wall of a Sports Club","authors":"M. Naqash","doi":"10.4236/OJCE.2019.91001","DOIUrl":"https://doi.org/10.4236/OJCE.2019.91001","url":null,"abstract":"The paper discusses the design, fabrication and the execution of the cladding supported by steel trusses and curtain wall of a sports club. The cladding and the curtain walls were subjected to a wind load of 1.2 Kpa considering basic wind speed of 25 m/s as per the project specifications. The first part of the paper deals with the cladding work of the canopy that consist of a 4 mm thick aluminium composite panels supported by steel trusses extended from the main structure. Two types of steel trusses were provided, the main truss connected to the space truss, whereas the intermediate truss connected to channels. Both trusses were spaced at 2.5 m centre to centre. These trusses were fabricated at factory and transported to the site for installation. The second part of the paper is related to the curtain wall design having Maximum Mullion spacing of 2 m, considered as worst scenario for the design calculations. The maximum Mullion height was 5.55 m, adopted in the calculations with bottom and top pinned connection. The Technal system was adopted for the design of mullions and transoms. Design was carried out using numerical modeling with CSI SAP2000 for cladding and its supporting structures. The bracket was realized and checked for the corresponding induced forces. All the structural systems were found safe according to different acceptance criterion.","PeriodicalId":302856,"journal":{"name":"Open Journal of Civil Engineering","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122113544","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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