Since the last four decades, the behavior of concrete contains of steel fiber, or often called steel fiber concrete, with a wide range of compressive strength has been carried out. Generally, the results of the experimental program produced a material which has a more ductile compared with normal concrete or concrete without fiber. Due to the ductility properties of the material, it is very suitable for use as an earthquake-resistant structural material. At the same time, the behavior of high-strength steel-fiber concrete has also investigated, one of which is about confined high-strength steel-fiber concrete. Analytical models of confined high-strength steel fiber concrete have been developed in various preliminary studies, with their characteristics derived based on the experimental results. Therefore, this research evaluated the models of confined high-strength steel-fiber concrete proposed by Mansur et al., Hsu and Hsu, and Paultre et al. The evaluation includes stress-strain behavior, strength enhancement of confined concrete (f'cc/f'co) or K value, the increase in confined concrete strain (ε'cc/ε'co), and strain of confined concrete when the stress has dropped by 50 percent against its unconfined strain (εcc50/εc50). The comparison method was carried out using a statistical approach and stress-strain simulation. Evaluation results showed significant predictive differences in confinement models in terms of post-peak behavior and parameters ε'cc/ε’co and εcc50/εc50. Prediction of confinement models on the value of f'cc/f’co to the experimental results has a coefficient of variation above 10%. The result further showed that a modified model of confined high-strength steel-fiber concrete was proposed and able to simulate the stress-strain behavior.
近四十年来，人们对含有钢纤维的混凝土，或常称为钢纤维混凝土的抗压强度进行了广泛的研究。一般来说，实验程序的结果产生的材料比普通混凝土或无纤维混凝土具有更大的延展性。由于材料的延展性，它非常适合用作抗震结构材料。同时，对高强钢纤维混凝土的性能进行了研究，其中一项是对承压高强钢纤维混凝土的性能进行了研究。在各种初步研究中建立了约束高强钢纤维混凝土的分析模型，其特征是基于试验结果得出的。因此，本研究对Mansur et al.、Hsu and Hsu、paulte et al.提出的承压高强钢纤维混凝土模型进行了评价。评估包括应力-应变特性、约束混凝土强度增强(f'cc/f'co)或K值、约束混凝土应变增加(ε'cc/ε'co)以及应力相对于非约束应变下降50%时约束混凝土的应变(εcc50/εc50)。采用统计方法和应力-应变模拟方法进行对比。评价结果表明，约束模型在峰后行为、ε'cc/ε ' co和εcc50/εc50参数方面的预测差异显著。约束模型对f'cc/f 'co值的预测与实验结果的变异系数在10%以上。结果进一步表明，提出了一种改进的约束型高强钢纤维混凝土模型，能够较好地模拟约束型高强钢纤维混凝土的应力-应变特性。
{"title":"A Comparative Study on the Confinement Models of High-Strength Steel Fiber Concrete","authors":"N. F. F. Cholida, Antonius, Lintang Enggartiasto","doi":"10.22146/jcef.4029","DOIUrl":"https://doi.org/10.22146/jcef.4029","url":null,"abstract":"Since the last four decades, the behavior of concrete contains of steel fiber, or often called steel fiber concrete, with a wide range of compressive strength has been carried out. Generally, the results of the experimental program produced a material which has a more ductile compared with normal concrete or concrete without fiber. Due to the ductility properties of the material, it is very suitable for use as an earthquake-resistant structural material. At the same time, the behavior of high-strength steel-fiber concrete has also investigated, one of which is about confined high-strength steel-fiber concrete. Analytical models of confined high-strength steel fiber concrete have been developed in various preliminary studies, with their characteristics derived based on the experimental results. Therefore, this research evaluated the models of confined high-strength steel-fiber concrete proposed by Mansur et al., Hsu and Hsu, and Paultre et al. The evaluation includes stress-strain behavior, strength enhancement of confined concrete (f'cc/f'co) or K value, the increase in confined concrete strain (ε'cc/ε'co), and strain of confined concrete when the stress has dropped by 50 percent against its unconfined strain (εcc50/εc50). The comparison method was carried out using a statistical approach and stress-strain simulation. Evaluation results showed significant predictive differences in confinement models in terms of post-peak behavior and parameters ε'cc/ε’co and εcc50/εc50. Prediction of confinement models on the value of f'cc/f’co to the experimental results has a coefficient of variation above 10%. The result further showed that a modified model of confined high-strength steel-fiber concrete was proposed and able to simulate the stress-strain behavior.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"os-9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87186753","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}
K. A. Utama, T. Harianto, Achmad Bakri Muhiddin, Ardy Arsyad
Landslides from Mount Bawakaraeng caldera in 2004 has caused high dam sedimentation at the lower reaches of the Jeneberang River. The availability of this large sedimentary material makes this material need to be considered as an alternative to new materials in the geotechnical field. However, the results of laboratory tests applied to sedimentary materials show that the mechanical characteristics of these materials are not sufficient for construction materials. Therefore, it is very important to conduct a study on how to improve the quality of dredged soil by adding Trass as stabilizing agent to improve the quality of the mechanical properties of the dredged soil. This study aims to analyze the mechanical characteristics of the dredged soil stabilized with Trass. The research was conducted by adding Trass with composition 3%; 6%; 9% and 12%; respectively to the dry weight of the dredged soil. The curing time was applied for a period of 3, 7 and 14 days to analyze the significant binding of Trass to the stabilized dredged soil. Laboratory tests was conducted to the density test and unconfined compression test. The results showed that there was an increase in the maximum dry density of the dredged soil between 1.41% - 3.56% due to the addition of trass, and a decrease in the optimum water content between 0.8% - 2.7%. In addition, there was an increase in the value of free compressive strength from 47.76% to 388.89% in the trass stabilized dredged soil during the curing period of 3, 7 and 14 days. The use of dredged soil and trass as stabilizing agent can be an alternative option in soil improvement efforts based on the utilization of waste material and local content potential.
{"title":"Compressive Strength Characteristics of Trass Stabilized Dredged Soil","authors":"K. A. Utama, T. Harianto, Achmad Bakri Muhiddin, Ardy Arsyad","doi":"10.22146/jcef.3463","DOIUrl":"https://doi.org/10.22146/jcef.3463","url":null,"abstract":"Landslides from Mount Bawakaraeng caldera in 2004 has caused high dam sedimentation at the lower reaches of the Jeneberang River. The availability of this large sedimentary material makes this material need to be considered as an alternative to new materials in the geotechnical field. However, the results of laboratory tests applied to sedimentary materials show that the mechanical characteristics of these materials are not sufficient for construction materials. Therefore, it is very important to conduct a study on how to improve the quality of dredged soil by adding Trass as stabilizing agent to improve the quality of the mechanical properties of the dredged soil. This study aims to analyze the mechanical characteristics of the dredged soil stabilized with Trass. The research was conducted by adding Trass with composition 3%; 6%; 9% and 12%; respectively to the dry weight of the dredged soil. The curing time was applied for a period of 3, 7 and 14 days to analyze the significant binding of Trass to the stabilized dredged soil. Laboratory tests was conducted to the density test and unconfined compression test. The results showed that there was an increase in the maximum dry density of the dredged soil between 1.41% - 3.56% due to the addition of trass, and a decrease in the optimum water content between 0.8% - 2.7%. In addition, there was an increase in the value of free compressive strength from 47.76% to 388.89% in the trass stabilized dredged soil during the curing period of 3, 7 and 14 days. The use of dredged soil and trass as stabilizing agent can be an alternative option in soil improvement efforts based on the utilization of waste material and local content potential.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90314163","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}
Erik Wahyu Pradana, A. Triwiyono, A. Awaludin, S. Mandal
Currently, 18,648 bridges with a total length of 510,366 km have been constructed in Indonesia, but only 86% are in good condition, while the rest are damaged. Steel truss bridge damage generally occurs on the RC decks, and its repair is often implemented through deck replacement or redecking using Orthotropic Steel Deck (OSD) panel. In Indonesia, this method has only been applied limitedly at the Citarum I Bridge in 2009 and the Cisadane Bridge in 2013, while the effect on the existing steel truss bridge is unknown. Therefore, this study aims to evaluate the steel truss bridge performance after OSD panel redecking through numerical modeling. The design process of the OSD panel was carried out by micro-modeling on ABAQUS CAE using shell elements with a mesh size of 50x50 mm and pinned boundary conditions. In this stage, the materials were assumed to be elastic with small deformations. The evaluation of steel truss bridge performance was performed on the A-class steel truss bridge Bina Marga design standard with a 60 m span by comparing the existing bridge inventory rating factor (using RC decks) to OSD panel redecking, which is an indicator of bridge self-weight reduction. Based on the structural macro-model developed using SAP2000, the bridge self-weight reduced the axial tension and compression forces on the steel truss bridge mainframe by 20.6%-24.6% and 20.5%-24.5%, respectively. Consequently, this increased the inventory rating factor by 9.3%-9.5%. In other words, using the OSD panels lighter than the existing RC decks increases the steel truss bridge capacity to resist the live load or vehicle rating throughout its service life.
{"title":"Increasing Inventory Rating Factor of Steel Truss Bridge Through Orthotropic Steel Deck Panel Application","authors":"Erik Wahyu Pradana, A. Triwiyono, A. Awaludin, S. Mandal","doi":"10.22146/jcef.3416","DOIUrl":"https://doi.org/10.22146/jcef.3416","url":null,"abstract":"Currently, 18,648 bridges with a total length of 510,366 km have been constructed in Indonesia, but only 86% are in good condition, while the rest are damaged. Steel truss bridge damage generally occurs on the RC decks, and its repair is often implemented through deck replacement or redecking using Orthotropic Steel Deck (OSD) panel. In Indonesia, this method has only been applied limitedly at the Citarum I Bridge in 2009 and the Cisadane Bridge in 2013, while the effect on the existing steel truss bridge is unknown. Therefore, this study aims to evaluate the steel truss bridge performance after OSD panel redecking through numerical modeling. The design process of the OSD panel was carried out by micro-modeling on ABAQUS CAE using shell elements with a mesh size of 50x50 mm and pinned boundary conditions. In this stage, the materials were assumed to be elastic with small deformations. The evaluation of steel truss bridge performance was performed on the A-class steel truss bridge Bina Marga design standard with a 60 m span by comparing the existing bridge inventory rating factor (using RC decks) to OSD panel redecking, which is an indicator of bridge self-weight reduction. Based on the structural macro-model developed using SAP2000, the bridge self-weight reduced the axial tension and compression forces on the steel truss bridge mainframe by 20.6%-24.6% and 20.5%-24.5%, respectively. Consequently, this increased the inventory rating factor by 9.3%-9.5%. In other words, using the OSD panels lighter than the existing RC decks increases the steel truss bridge capacity to resist the live load or vehicle rating throughout its service life.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76087678","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 Palu 28 September 2021 M 7.5 Earthquake has brought several new challenges to the understanding of liquefaction and its following geotechnical phenomena. In addition, that main shock was followed by a series of aftershocks within a short time frame. The common geotechnical conditions of Palu area include layered soils conditions, and the associated variability of geotechnical conditions exists. This paper reports the dynamic effective stress analysis (ESA) study of four different liquefiable layered sand columns, and the above three conditions (layered soils, variability, aftershocks) are explicitly modeled. The dynamic ESA employs the PM4Sand constitutive model for liquefiable sands, implemented in the OpenSees platform. Three ground motion sets (“main shock only”, “main shock plus aftershock”, “aftershock” only) of variable amplitude, single frequency harmonic motions are used. The models are validated by comparing qualitatively their results against laboratory test results and field measurements. The saturated sand layers in all cases subjected to “main shock only” are liquefied with different detailed excess pore pressure (EPP) responses, highlighting the importance of the system response of liquefying sand columns. The cases subjected to “main shock plus aftershock” show a much a longer higher EPP state, while cases subjected to both “main shock plus aftershock” and “aftershock only” indicate a longer liquefaction state during the aftershock. The implication of the longer duration in the higher EPP state and the longer liquefaction state is that a longer duration of lower shear strength conditions would exist. The different EPP responses resulted from different geotechnical conditions represented by the four sand columns suggest that the variability of geotechnical conditions would have an important influence on the system response.
{"title":"Pore Pressure Responses of Liquefied Numerical Sand Columns","authors":"W. Prakoso, D. Mazaya, Rumaisha A. Kartika","doi":"10.22146/jcef.3395","DOIUrl":"https://doi.org/10.22146/jcef.3395","url":null,"abstract":"The Palu 28 September 2021 M 7.5 Earthquake has brought several new challenges to the understanding of liquefaction and its following geotechnical phenomena. In addition, that main shock was followed by a series of aftershocks within a short time frame. The common geotechnical conditions of Palu area include layered soils conditions, and the associated variability of geotechnical conditions exists. This paper reports the dynamic effective stress analysis (ESA) study of four different liquefiable layered sand columns, and the above three conditions (layered soils, variability, aftershocks) are explicitly modeled. The dynamic ESA employs the PM4Sand constitutive model for liquefiable sands, implemented in the OpenSees platform. Three ground motion sets (“main shock only”, “main shock plus aftershock”, “aftershock” only) of variable amplitude, single frequency harmonic motions are used. The models are validated by comparing qualitatively their results against laboratory test results and field measurements. The saturated sand layers in all cases subjected to “main shock only” are liquefied with different detailed excess pore pressure (EPP) responses, highlighting the importance of the system response of liquefying sand columns. The cases subjected to “main shock plus aftershock” show a much a longer higher EPP state, while cases subjected to both “main shock plus aftershock” and “aftershock only” indicate a longer liquefaction state during the aftershock. The implication of the longer duration in the higher EPP state and the longer liquefaction state is that a longer duration of lower shear strength conditions would exist. The different EPP responses resulted from different geotechnical conditions represented by the four sand columns suggest that the variability of geotechnical conditions would have an important influence on the system response.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84686473","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}
Several CPT-SPT correlations have been reported worldwide to allow for the estimate of soil physical properties from one set of accessible data to another. Although most correlations are for silty and sandy soils, there is insufficient information on whether these correlations correspond to the silty clay soil conditions in Indonesia. Therefore, this study aims is to validate and enhance the generalized CPT-SPT correlation, with emphasis on Indonesian soil conditions to increase its prediction accuracy. The soil under examination is silty clay layers that cover most of Northern parts of West Java – Indonesia. Known with its expansive clay characteristics, these type of soils are sensitive to volume change as a result of seasonal variations in water content. For this study, data is collected from 8 (eight) locations in Cikarang Area. Each location consists of dedicated SPT and CPT pairs tests at 2 (two) m distance between each other. After analyzed with various statistical regression analysis of data relevant to this type of soil, a simple linear empirical CPT-SPT correlation with a fairly high correlation has been established allowing test findings to be translated and predicted for the relevant soils type. The simple CPT and SPT correlation is in form of n = qc/NSPT = 0.225 (Mpa), with data distribution of n ranges from 0.15 (Mpa) to 0.33 (Mpa). This results shows much lower n values compared to various correlation have been published worldwide. With respect to the clay soil formation, the low of n-value also reflect a lower density and cohesion bonding clay properties.
{"title":"SPT and CPT Correlation of Expansive Clay in Cikarang, Indonesia","authors":"Eddy Triyanto Sudjatmiko","doi":"10.22146/jcef.3458","DOIUrl":"https://doi.org/10.22146/jcef.3458","url":null,"abstract":"Several CPT-SPT correlations have been reported worldwide to allow for the estimate of soil physical properties from one set of accessible data to another. Although most correlations are for silty and sandy soils, there is insufficient information on whether these correlations correspond to the silty clay soil conditions in Indonesia. Therefore, this study aims is to validate and enhance the generalized CPT-SPT correlation, with emphasis on Indonesian soil conditions to increase its prediction accuracy. The soil under examination is silty clay layers that cover most of Northern parts of West Java – Indonesia. Known with its expansive clay characteristics, these type of soils are sensitive to volume change as a result of seasonal variations in water content. For this study, data is collected from 8 (eight) locations in Cikarang Area. Each location consists of dedicated SPT and CPT pairs tests at 2 (two) m distance between each other. After analyzed with various statistical regression analysis of data relevant to this type of soil, a simple linear empirical CPT-SPT correlation with a fairly high correlation has been established allowing test findings to be translated and predicted for the relevant soils type. The simple CPT and SPT correlation is in form of n = qc/NSPT = 0.225 (Mpa), with data distribution of n ranges from 0.15 (Mpa) to 0.33 (Mpa). This results shows much lower n values compared to various correlation have been published worldwide. With respect to the clay soil formation, the low of n-value also reflect a lower density and cohesion bonding clay properties.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"217 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76772964","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 on expansive soils can easily change in volume due to the influence of water content. This makes it necessary to consider soil improvement methods in the planning process to maintain the variation in the water content. One of these methods includes chemical stabilization, which is carried out by adding materials such as cement or lime. In expansive soils, stabilization efforts aim to reduce the plasticity index and increase the shear strength parameters. Therefore, this study focused on the addition of slaked lime (Ca(OH)2) to expansive soil in Lakarsantri, Surabaya. The stabilizing materials used contain calcium to form pozzolan in the clay and increase the bearing capacity parameter, which is variation in shear strength. The soil was taken at 2 points A and B with a different moisture content of 48.57% and 35.12%, as well as a high plasticity index value > 50% using a percentage (Ca(OH)2) of 6%-24% at a certain curing time. Based on the results, the plasticity index in the soil changed from very high to moderate with an optimum percentage value of 6% at 30 days of curing time. The optimum value of soil shear strength is (Ca(OH)2) 6% at 30 days of age in soil A, the cohesion value is 0.02 kg/cm2, and an internal shear angle of 36°. In soil B, the optimum shear strength obtained (Ca(OH)2) was 6% at the age of 10 days with a cohesion value of 0.14 kg/cm2 and an internal shear angle of 23.80°. Therefore, the results of this study show that the parameter of shear strength of the soil from the cohesion value showed that the cohesion value decreased with the addition of Ca(OH)2, while the internal shear angle increased.
{"title":"The Performance of Ca(OH)2 to Reduce the Plasticity Index and Increase the Shear Strength Parameter for Expansive Soil","authors":"Mila Kusuma Wardani, P. Sari, Mafrita Refionasari","doi":"10.22146/jcef.3455","DOIUrl":"https://doi.org/10.22146/jcef.3455","url":null,"abstract":"The design on expansive soils can easily change in volume due to the influence of water content. This makes it necessary to consider soil improvement methods in the planning process to maintain the variation in the water content. One of these methods includes chemical stabilization, which is carried out by adding materials such as cement or lime. In expansive soils, stabilization efforts aim to reduce the plasticity index and increase the shear strength parameters. Therefore, this study focused on the addition of slaked lime (Ca(OH)2) to expansive soil in Lakarsantri, Surabaya. The stabilizing materials used contain calcium to form pozzolan in the clay and increase the bearing capacity parameter, which is variation in shear strength. The soil was taken at 2 points A and B with a different moisture content of 48.57% and 35.12%, as well as a high plasticity index value > 50% using a percentage (Ca(OH)2) of 6%-24% at a certain curing time. Based on the results, the plasticity index in the soil changed from very high to moderate with an optimum percentage value of 6% at 30 days of curing time. The optimum value of soil shear strength is (Ca(OH)2) 6% at 30 days of age in soil A, the cohesion value is 0.02 kg/cm2, and an internal shear angle of 36°. In soil B, the optimum shear strength obtained (Ca(OH)2) was 6% at the age of 10 days with a cohesion value of 0.14 kg/cm2 and an internal shear angle of 23.80°. Therefore, the results of this study show that the parameter of shear strength of the soil from the cohesion value showed that the cohesion value decreased with the addition of Ca(OH)2, while the internal shear angle increased.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87477436","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}
Downhole dynamic compaction (DDC) has been commonly used in China to stabilize collapsible soil through the application of construction and demolition waste material (CDW). DDC basically forms a column inside the soil stratum which is similar to a stone column except DDC materials are put in sequence and then compacted by using DDC hammer. Due to its attractive features such as its big diameter, feasibility of using oversized material particles, rapid and simple construction technique, it is used as one of the ground improvement methods for an airport project in Indonesia. Despite of all the advantages provided by DDC, it is difficult to obtain DDC parameters from laboratory tests as it is difficult to replicate the compaction effort induced by the DDC hammer and laboratory tests are not commonly employed for oversized materials. Hence, alternative method is required to evaluate DDC parameters. In this study, static load test is conducted to determine load-deformation curve of the DDC pile. Soil parameters are first determined through soil test data such as standard penetration test (SPT), laboratory test and also pressure meter tests. Correlation between pressure meter tests and SPT test result is also carried in order to interpret the soil parameter at the site. Axisymmetric finite element analysis is then carried by using MIDAS GTS NX in order to back analyses DDC parameters by matching the simulation curve with load settlement curve of the DDC. In this paper, it is shown that back analysis using hardening soil model for DDC material can be used to match simulation curve with the load-deformation curve.
{"title":"The Determination of Downhole Dynamic Compaction Paramaters Based on Finite Element Analysis","authors":"M. Wijaya, A. Arsyad, Aswin Lim, P. Rahardjo","doi":"10.22146/jcef.3467","DOIUrl":"https://doi.org/10.22146/jcef.3467","url":null,"abstract":"Downhole dynamic compaction (DDC) has been commonly used in China to stabilize collapsible soil through the application of construction and demolition waste material (CDW). DDC basically forms a column inside the soil stratum which is similar to a stone column except DDC materials are put in sequence and then compacted by using DDC hammer. Due to its attractive features such as its big diameter, feasibility of using oversized material particles, rapid and simple construction technique, it is used as one of the ground improvement methods for an airport project in Indonesia. Despite of all the advantages provided by DDC, it is difficult to obtain DDC parameters from laboratory tests as it is difficult to replicate the compaction effort induced by the DDC hammer and laboratory tests are not commonly employed for oversized materials. Hence, alternative method is required to evaluate DDC parameters. In this study, static load test is conducted to determine load-deformation curve of the DDC pile. Soil parameters are first determined through soil test data such as standard penetration test (SPT), laboratory test and also pressure meter tests. Correlation between pressure meter tests and SPT test result is also carried in order to interpret the soil parameter at the site. Axisymmetric finite element analysis is then carried by using MIDAS GTS NX in order to back analyses DDC parameters by matching the simulation curve with load settlement curve of the DDC. In this paper, it is shown that back analysis using hardening soil model for DDC material can be used to match simulation curve with the load-deformation curve.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79141351","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. Rosyidah, Jasun Widiana Putra, Jonathan Saputra
The embedment length influences the adhesion between the cast iron material and the concrete. The concrete's compression strength also contributes to an increase in bond strength. Therefore, this research aims to determine the maximum pullout force on each variation of the anchor and the optimal embedment length. A gauge is modeled as a rod-type with a diameter of 16 mm, and the embedment lengths used are 5D, 10D, and 15D, while the compressive strengths include fc’ 20, 30, 40, 50, and 60 MPa. Furthermore, a finite element-based application was utilized with the ANSYS Workbench student version. The result showed that the concrete with strengths of 20, 30, 40, 50, and 60 MPa has maximum pullout forces of 27.011, 53.536, 68.657, 68.970, and 84.407 kN, respectively at an embedment length of 15D. It was observed that the failure pattern obtained starts from the defect in the concrete cone and ends with the breakage of reinforcement or steel failure at each variation of concrete strength. A combination of two non-parametric techniques was used in this research, which includes Kruskal Wallis and U-Mann Whitney test. The first technique revealed that the chi-square value for strengths 20, 40, 50, and 60 MPa is 9.486, while that of 30 MPa is 9.881. The second test employed showed a significance value below 0.05. In conclusion, the embedment length affected the value of pullout force, and 15D was the optimum embedment length for each variation of concrete strength. The enhancement in tensile strength increases with the strength of the concrete.
{"title":"Chemical Anchor Pullout Force Modeling with Variation of Anchor Embedment Length in Concrete and Concrete Strength","authors":"A. Rosyidah, Jasun Widiana Putra, Jonathan Saputra","doi":"10.22146/jcef.3769","DOIUrl":"https://doi.org/10.22146/jcef.3769","url":null,"abstract":"The embedment length influences the adhesion between the cast iron material and the concrete. The concrete's compression strength also contributes to an increase in bond strength. Therefore, this research aims to determine the maximum pullout force on each variation of the anchor and the optimal embedment length. A gauge is modeled as a rod-type with a diameter of 16 mm, and the embedment lengths used are 5D, 10D, and 15D, while the compressive strengths include fc’ 20, 30, 40, 50, and 60 MPa. Furthermore, a finite element-based application was utilized with the ANSYS Workbench student version. The result showed that the concrete with strengths of 20, 30, 40, 50, and 60 MPa has maximum pullout forces of 27.011, 53.536, 68.657, 68.970, and 84.407 kN, respectively at an embedment length of 15D. It was observed that the failure pattern obtained starts from the defect in the concrete cone and ends with the breakage of reinforcement or steel failure at each variation of concrete strength. A combination of two non-parametric techniques was used in this research, which includes Kruskal Wallis and U-Mann Whitney test. The first technique revealed that the chi-square value for strengths 20, 40, 50, and 60 MPa is 9.486, while that of 30 MPa is 9.881. The second test employed showed a significance value below 0.05. In conclusion, the embedment length affected the value of pullout force, and 15D was the optimum embedment length for each variation of concrete strength. The enhancement in tensile strength increases with the strength of the concrete.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81903031","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}
Rice husk ash (RHA) is an industrial waste obtained from raw material that is processed into ash through the combustion process. It is a solid waste in fine powder form, which contains a large amount of silica and can promote RHA through combustion under certain conditions. Furthermore, it has a high pozzolanic activity due to a large amount of silica, which is a kind of supplementary cementitious material (SCM). According to ASTM C618, RHA has potential as sustainable material that meets the specification of the chemical configuration of pozzolan compound that can be used in cement products and concrete mixing. The use of RHA as SCMs in concrete construction contributes to sustainability and eco-material. Therefore, this study aims to evaluate the application of RHA as SCM on the strength base performance of concrete. The sample was directly collected from the rice field after the natural combusting process without additional treatment, controlled burning temperature, or time. RHA was used as an admixture for cement substitute and the mechanical characteristics were evaluated using a cylindrical concrete specimen made with 100-mm diameter and 200-mm height. After 24-hours, the concrete specimens were demolded and immediately immersed curing in fresh water with uncontrolled laboratory condition until the day of testing. The results showed that RHA with a replacement ratio of 7.5% obtained an optimum compressive strength of 40.65 MPa and 48.79 MPa at 28 and 91 days, respectively. The split tensile test also gave an optimum replacement ratio of RHA is 10% with 4.57 MPa at 28 days. These results provide good input on using RHA as SCM for concrete strength base performance and future sustainable material.
{"title":"Strength Performance of Concrete Using Rice Husk Ash (RHA) as Supplementary Cementitious Material (SCM)","authors":"D. Patah, A. Dasar","doi":"10.22146/jcef.3488","DOIUrl":"https://doi.org/10.22146/jcef.3488","url":null,"abstract":"Rice husk ash (RHA) is an industrial waste obtained from raw material that is processed into ash through the combustion process. It is a solid waste in fine powder form, which contains a large amount of silica and can promote RHA through combustion under certain conditions. Furthermore, it has a high pozzolanic activity due to a large amount of silica, which is a kind of supplementary cementitious material (SCM). According to ASTM C618, RHA has potential as sustainable material that meets the specification of the chemical configuration of pozzolan compound that can be used in cement products and concrete mixing. The use of RHA as SCMs in concrete construction contributes to sustainability and eco-material. Therefore, this study aims to evaluate the application of RHA as SCM on the strength base performance of concrete. The sample was directly collected from the rice field after the natural combusting process without additional treatment, controlled burning temperature, or time. RHA was used as an admixture for cement substitute and the mechanical characteristics were evaluated using a cylindrical concrete specimen made with 100-mm diameter and 200-mm height. After 24-hours, the concrete specimens were demolded and immediately immersed curing in fresh water with uncontrolled laboratory condition until the day of testing. The results showed that RHA with a replacement ratio of 7.5% obtained an optimum compressive strength of 40.65 MPa and 48.79 MPa at 28 and 91 days, respectively. The split tensile test also gave an optimum replacement ratio of RHA is 10% with 4.57 MPa at 28 days. These results provide good input on using RHA as SCM for concrete strength base performance and future sustainable material.","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78833242","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}
P. T. Simatupang, Idrus M. Alatas, Ayu K. Redyananda, Eko A. Purnomo
The use of weathered clay shale often has the potential to cause geotechnical problems as an embankment material, especially slope failures. In order for weathered clay shale to be used as embankment material, the weathered clay shale must be mixed with other materials. An example of a widely used mix is a mix with a Portland cement (PC). In general, this mixture will increase the shear strength of the embankment material. In addition to shear strength, it is very important to investigate whether the material mixture is susceptible to durability. Therefore, this study aims to evaluate the shear strength and durability behaviors of weathered clay shale mixture, using PC. The percentage of this cement was varied and did not exceed 20%, with the mixing material also compacted based on Proctor Standard procedure. This test included the determination of shear strength and durability index at the smaller and larger (dry and wet sides) than optimum moisture content (OMC). Shear strength and durability index were determined by Triaxial and slake durability index tests, respectively. The results showed that the weathered clay mixture with 10% PC and 8% larger OMC led to an increase in the normalized shear strength (∆σ/σ) and durability index at approximately 300% and 24%, respectively, compared to the original clay shale. This indicated that the optimum shear strength and durability of this shale mixture were highly observed at 10% PC and 8% larger OMC (wet side). This verified also although the durability index increased by 97% with the addition of 20% PC, whose utilization was found to be unrealistic
{"title":"Shear Strength and Durability Behaviors of Compacted Weathered Clay Shale Mixture Using Portland Cement","authors":"P. T. Simatupang, Idrus M. Alatas, Ayu K. Redyananda, Eko A. Purnomo","doi":"10.22146/jcef.3491","DOIUrl":"https://doi.org/10.22146/jcef.3491","url":null,"abstract":"The use of weathered clay shale often has the potential to cause geotechnical problems as an embankment material, especially slope failures. In order for weathered clay shale to be used as embankment material, the weathered clay shale must be mixed with other materials. An example of a widely used mix is a mix with a Portland cement (PC). In general, this mixture will increase the shear strength of the embankment material. In addition to shear strength, it is very important to investigate whether the material mixture is susceptible to durability. Therefore, this study aims to evaluate the shear strength and durability behaviors of weathered clay shale mixture, using PC. The percentage of this cement was varied and did not exceed 20%, with the mixing material also compacted based on Proctor Standard procedure. This test included the determination of shear strength and durability index at the smaller and larger (dry and wet sides) than optimum moisture content (OMC). Shear strength and durability index were determined by Triaxial and slake durability index tests, respectively. The results showed that the weathered clay mixture with 10% PC and 8% larger OMC led to an increase in the normalized shear strength (∆σ/σ) and durability index at approximately 300% and 24%, respectively, compared to the original clay shale. This indicated that the optimum shear strength and durability of this shale mixture were highly observed at 10% PC and 8% larger OMC (wet side). This verified also although the durability index increased by 97% with the addition of 20% PC, whose utilization was found to be unrealistic","PeriodicalId":31890,"journal":{"name":"Journal of the Civil Engineering Forum","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88049450","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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