Sari Abusharar | University of Palestine (original) (raw)
Papers by Sari Abusharar
Innovative Systems Design and Engineering, 2015
This paper investigates the mechanical properties of concrete containing different particle sizes... more This paper investigates the mechanical properties of concrete containing different particle sizes of crumb rubber. This research have been conducted on 10% replacement of fine aggregates by three different particle sizes of crumb rubber which are 1 mm crumb rubber, 0.4-1 mm fine dust crumb rubber, and 0.2-0.6 mm powder crumb rubber. Laboratory tests include slump test, compressive test, flexural test, bulk density test, water absorption test, porosity test, and ultrasonic pulse velocity (UPV) test were conducted on the concrete mixes. All concrete specimens were tested at the age of 7, 14, 28, and 56 days. The results from laboratory testing on concrete specimens were analyzed. It was found that in the inclusion of crumb rubber into concrete, it will reduce the strength of concrete. The usage of greater particle sizes of crumb rubber which is 1 mm crumb rubber gives better strength of concrete compared to the usage of smaller particle sizes of crumb rubber which is 0.2-0.6 mm powder crumb rubber. Therefore, the rubberized concrete can absorb the impact energy and suitable usage in roads and highways construction such as road divider, road pavement, and others because it can absorb impact from vehicles load, disaster and others.
Engineering Geology, Jun 1, 2011
A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor ... more A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor of safety (FS) against deep-seated failure of embankments over stone column-improved soft clay based on individual column and equivalent area models. In the equivalent area model, the equivalent parameters (unit weight, cohesion, and friction angle) for the improved area were estimated based on the area average of the parameters from stone columns and soft clay. The factors influencing the FS against deep-seated failure of embankments over stone column-improved soft clay were investigated including the spacing, size, and friction angle of stone columns, cohesion of soft clay, friction angle and height of embankment fill, and existence of ground water. Based on the numerical results, a reduction factor was proposed to account for the difference in the FS when the individual column model is converted to the equivalent area model. The effects of the influence factors on the reduction factor were also investigated. The comparative study shows that the FS values obtained by the equivalent area model are higher than those by the individual column model. The results of these analyses are summarized into a series of design charts, which can be used in engineering practice. A reduction factor for FS of 0.90 is appropriate to convert the calculated FS by the equivalent area model to that by the individual column model based on the current study. Furthermore, the existence of the water table results in lower FS values than the cases without considering a water table because the groundwater reduces the shear strength of the improved foundation.
The aim of this study is to assess the most common impacts of construction projects on the enviro... more The aim of this study is to assess the most common impacts of construction projects on the environment in the Gaza Strip and propose the best solutions in curbing down the adverse impacts. To achieve this aim, a structured survey, in the form of a questionnaire was conducted to identify the most critical and important impacts of construction projects on the environment. Environmental impacts were categorized into three safeguard subjects: ecosystems, natural resources, and public impacts. The results showed that dust generation, noise pollution, operations with vegetation removal, and air pollution are the most significant environmental impacts of construction sites in the Gaza Strip. In addition, the public impacts are the most important category that affects the environment in the Gaza Strip. Furthermore, the results demonstrated that the necessity of taking measures to protect labors and residents who are living near to construction sites. It is recommended to enhance the knowled...
This paper investigates the influence of volcanic ash (VA) and vinyl acetate/ethylene copolymer p... more This paper investigates the influence of volcanic ash (VA) and vinyl acetate/ethylene copolymer powder (PVA/VE) as partial cement replacement on the engineering properties of blended binders concretes. The parameters studied included density, workability and compressive strength. A total number of 12 trial mixtures were prepared and tested by varying the proportions of binders. Firstly, VA was used to replace OPC at dosage levels of 5%, 10%, 15%, 20%, 25%, and 50% by weight of the binder. Secondly, PVA/VE was used to replace OPC at dosage levels of 0.5%, 1%, 1.5%, 2% and 2.50% by weight of the binder. Finally, the optimum replacement levels of VA and PVA/VE were determined and used to prepare a new trial mix. The results show that cement replacement up to 15% volcanic ash and 1.5% PVE/VE leads to increase in workability and compressive strength for C30 grade compared with the control mixture.
Geosynthetics in Civil and Environmental Engineering, 2009
ABSTRACT The vertical reinforcement (pile walls) is combined with the horizontal reinforcement (g... more ABSTRACT The vertical reinforcement (pile walls) is combined with the horizontal reinforcement (geosynthetics) to provide an economical and effective solution for ground treatment of high embankments constructed on soft soil. Theoretical and numerical analyses were conducted to investigate the interaction among geosynthetics, pile walls and soft soil. The differential settlement between pile wall and soft soil will generate soil arching in embankment fill. Soil arching and tensioned membrane of geosynthetics are combined to transfer embankment loads from soft soil to competent substratum (such as bedrock) through pile walls, which minimize the yielding of the soft soil and potentially reduce the total and differential settlements. The soil arching efficiency, the pile wall efficiency, the differential settlement of the embankment, and the distribution of tension force in the geosynthetics have been analyzed with the consideration of four major influencing factors: the elastic modulus of the pile wall, the tensile stiffness of the geosynthetics, the height of the embankment fill, and the area ratio of the pile wall. Some conclusions are drawn as a reference for the design and construction of geosynthetic-reinforced and pile wall-supported embankment over soft ground.
Geosynthetics International, 2009
The construction of high embankments on soft ground faces several challenges, such as potential b... more The construction of high embankments on soft ground faces several challenges, such as potential bearing capacity failure, global slope instability, local failure, large total and/or differential settlements, and large lateral movement during both construction and post-...
Engineering Geology, 2011
A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor ... more A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor of safety (FS) against deep-seated failure of embankments over stone column-improved soft clay based on individual column and equivalent area models. In the equivalent area model, the equivalent parameters (unit weight, cohesion, and friction angle) for the improved area were estimated based on the area average of the parameters from stone columns and soft clay. The factors influencing the FS against deep-seated failure of embankments over stone column-improved soft clay were investigated including the spacing, size, and friction angle of stone columns, cohesion of soft clay, friction angle and height of embankment fill, and existence of ground water. Based on the numerical results, a reduction factor was proposed to account for the difference in the FS when the individual column model is converted to the equivalent area model. The effects of the influence factors on the reduction factor were also investigated. The comparative study shows that the FS values obtained by the equivalent area model are higher than those by the individual column model. The results of these analyses are summarized into a series of design charts, which can be used in engineering practice. A reduction factor for FS of 0.90 is appropriate to convert the calculated FS by the equivalent area model to that by the individual column model based on the current study. Furthermore, the existence of the water table results in lower FS values than the cases without considering a water table because the groundwater reduces the shear strength of the improved foundation.
Computers and Geotechnics, 2009
ABSTRACT A multi-column composite foundation is a new concept utilizing different column types wi... more ABSTRACT A multi-column composite foundation is a new concept utilizing different column types with varying lengths and diameters to support the embankment fill and to mobilize the strength and stiffness of the soil at shallow depths. This study presents the results of finite element analyses using the finite element software PLAXIS to investigate the consolidation behavior of a road embankment constructed on a multi-column composite foundation. The finite element results are calibrated for a period of 200 days. The settlement, horizontal displacement, differential settlement, column axial force, and the development and dissipation of excess pore pressure are presented and discussed in detail. It is concluded that a multi-column composite foundation allows a fast rate of consolidation and significantly increases the embankment stability. A multi-column composite foundation formed by CFG–lime columns is more effective than one formed by SC–lime columns. The CFG–lime columns improve the long-term stability of the embankment because the compression modulus of CFG columns is significantly greater than that of SC columns.
Piled embankments provide an economic solution to the problem of constructing embankments over so... more Piled embankments provide an economic solution to the problem of constructing embankments over soft soils. The piles and geosynthetic combination can alleviate the uneven surface settlements that sometimes occur in embankments supported by piles without reinforcement. The main focus of this paper is to present a new method for analysis of an embankment of granular fill on soft ground supported by a rectangular grid of piles and geosynthetic. This method is based on consideration of the arching effect in granular soil and similar to the method proposed by Low, B.. The main refinements are: inclusion of a uniform surcharge load on the embankment fill, individual square caps were used, and taking into account the skin friction mechanism, which contributes to soil–geosynthetic interface resistance. Using this method, the influence of embankment height, soft ground depth, soft ground elastic modulus, and geosynthetic tensile stiffness on efficiency, stress concentration ratio, settlement ratio, tension of geosynthetic, and axial strain of geosynthetic are investigated. The results show that inclusion of a geosynthetic membrane can increase the fill load carried by piles. As a result, both the total and differential settlements of the embankment can be reduced. The new design method was verified against several current design methods. Theoretical solution showed that BS8006 [1995. Code of Practice for Strengthened/Reinforced Soils and other Fills. British Standards Institution, London, p. 162] and Guido, V.A., Kneuppel, J.D., Sweeny, M.A. [1987. Plate loading tests on geogrid-reinforced earth slabs. In: Proceedings of the Geosynthetics '87, New Orleans, USA, IFAI, pp. 216–225] methods overpredict the vertical stress acting on the geosynthetic due to that the reaction of the soft ground on the geosynthetic is not considered in their methods. It also showed that the present method is in good agreement with Low, B.
Cement–Flyash–Gravel (CFG) pile is a widely used ground improvement technique. A CFG–lime multi-p... more Cement–Flyash–Gravel (CFG) pile is a widely used ground improvement technique. A CFG–lime multi-pile composite foundation is a new concept utilizing CFG and lime piles. This study presents the results of finite element analyzes using ANSYS software to investigate the behavior of composite CFG–lime pile foundations under various load distributions. The parameters studied include the length and diameter of piles and the thickness of the cushion. The stress distribution beneath the composite foundation, the influence of the cushion on load-settlement behavior, and the ratio of stresses in the piles to those in the subsoil are also studied. The results show that settlement is much more significantly affected by the length and diameter of the CFG pile rather than that of the lime pile. This suggests that the CFG pile indeed acts as a settlement-reducing pile, which is in accordance with the working principle of such composite foundations. On the other hand, the load distribution between piles and subsoil is significantly affected by the cushion thickness.
Innovative Systems Design and Engineering, 2015
This paper investigates the mechanical properties of concrete containing different particle sizes... more This paper investigates the mechanical properties of concrete containing different particle sizes of crumb rubber. This research have been conducted on 10% replacement of fine aggregates by three different particle sizes of crumb rubber which are 1 mm crumb rubber, 0.4-1 mm fine dust crumb rubber, and 0.2-0.6 mm powder crumb rubber. Laboratory tests include slump test, compressive test, flexural test, bulk density test, water absorption test, porosity test, and ultrasonic pulse velocity (UPV) test were conducted on the concrete mixes. All concrete specimens were tested at the age of 7, 14, 28, and 56 days. The results from laboratory testing on concrete specimens were analyzed. It was found that in the inclusion of crumb rubber into concrete, it will reduce the strength of concrete. The usage of greater particle sizes of crumb rubber which is 1 mm crumb rubber gives better strength of concrete compared to the usage of smaller particle sizes of crumb rubber which is 0.2-0.6 mm powder crumb rubber. Therefore, the rubberized concrete can absorb the impact energy and suitable usage in roads and highways construction such as road divider, road pavement, and others because it can absorb impact from vehicles load, disaster and others.
Engineering Geology, Jun 1, 2011
A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor ... more A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor of safety (FS) against deep-seated failure of embankments over stone column-improved soft clay based on individual column and equivalent area models. In the equivalent area model, the equivalent parameters (unit weight, cohesion, and friction angle) for the improved area were estimated based on the area average of the parameters from stone columns and soft clay. The factors influencing the FS against deep-seated failure of embankments over stone column-improved soft clay were investigated including the spacing, size, and friction angle of stone columns, cohesion of soft clay, friction angle and height of embankment fill, and existence of ground water. Based on the numerical results, a reduction factor was proposed to account for the difference in the FS when the individual column model is converted to the equivalent area model. The effects of the influence factors on the reduction factor were also investigated. The comparative study shows that the FS values obtained by the equivalent area model are higher than those by the individual column model. The results of these analyses are summarized into a series of design charts, which can be used in engineering practice. A reduction factor for FS of 0.90 is appropriate to convert the calculated FS by the equivalent area model to that by the individual column model based on the current study. Furthermore, the existence of the water table results in lower FS values than the cases without considering a water table because the groundwater reduces the shear strength of the improved foundation.
The aim of this study is to assess the most common impacts of construction projects on the enviro... more The aim of this study is to assess the most common impacts of construction projects on the environment in the Gaza Strip and propose the best solutions in curbing down the adverse impacts. To achieve this aim, a structured survey, in the form of a questionnaire was conducted to identify the most critical and important impacts of construction projects on the environment. Environmental impacts were categorized into three safeguard subjects: ecosystems, natural resources, and public impacts. The results showed that dust generation, noise pollution, operations with vegetation removal, and air pollution are the most significant environmental impacts of construction sites in the Gaza Strip. In addition, the public impacts are the most important category that affects the environment in the Gaza Strip. Furthermore, the results demonstrated that the necessity of taking measures to protect labors and residents who are living near to construction sites. It is recommended to enhance the knowled...
This paper investigates the influence of volcanic ash (VA) and vinyl acetate/ethylene copolymer p... more This paper investigates the influence of volcanic ash (VA) and vinyl acetate/ethylene copolymer powder (PVA/VE) as partial cement replacement on the engineering properties of blended binders concretes. The parameters studied included density, workability and compressive strength. A total number of 12 trial mixtures were prepared and tested by varying the proportions of binders. Firstly, VA was used to replace OPC at dosage levels of 5%, 10%, 15%, 20%, 25%, and 50% by weight of the binder. Secondly, PVA/VE was used to replace OPC at dosage levels of 0.5%, 1%, 1.5%, 2% and 2.50% by weight of the binder. Finally, the optimum replacement levels of VA and PVA/VE were determined and used to prepare a new trial mix. The results show that cement replacement up to 15% volcanic ash and 1.5% PVE/VE leads to increase in workability and compressive strength for C30 grade compared with the control mixture.
Geosynthetics in Civil and Environmental Engineering, 2009
ABSTRACT The vertical reinforcement (pile walls) is combined with the horizontal reinforcement (g... more ABSTRACT The vertical reinforcement (pile walls) is combined with the horizontal reinforcement (geosynthetics) to provide an economical and effective solution for ground treatment of high embankments constructed on soft soil. Theoretical and numerical analyses were conducted to investigate the interaction among geosynthetics, pile walls and soft soil. The differential settlement between pile wall and soft soil will generate soil arching in embankment fill. Soil arching and tensioned membrane of geosynthetics are combined to transfer embankment loads from soft soil to competent substratum (such as bedrock) through pile walls, which minimize the yielding of the soft soil and potentially reduce the total and differential settlements. The soil arching efficiency, the pile wall efficiency, the differential settlement of the embankment, and the distribution of tension force in the geosynthetics have been analyzed with the consideration of four major influencing factors: the elastic modulus of the pile wall, the tensile stiffness of the geosynthetics, the height of the embankment fill, and the area ratio of the pile wall. Some conclusions are drawn as a reference for the design and construction of geosynthetic-reinforced and pile wall-supported embankment over soft ground.
Geosynthetics International, 2009
The construction of high embankments on soft ground faces several challenges, such as potential b... more The construction of high embankments on soft ground faces several challenges, such as potential bearing capacity failure, global slope instability, local failure, large total and/or differential settlements, and large lateral movement during both construction and post-...
Engineering Geology, 2011
A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor ... more A two-dimensional (2D) finite difference method was adopted in this study to estimate the factor of safety (FS) against deep-seated failure of embankments over stone column-improved soft clay based on individual column and equivalent area models. In the equivalent area model, the equivalent parameters (unit weight, cohesion, and friction angle) for the improved area were estimated based on the area average of the parameters from stone columns and soft clay. The factors influencing the FS against deep-seated failure of embankments over stone column-improved soft clay were investigated including the spacing, size, and friction angle of stone columns, cohesion of soft clay, friction angle and height of embankment fill, and existence of ground water. Based on the numerical results, a reduction factor was proposed to account for the difference in the FS when the individual column model is converted to the equivalent area model. The effects of the influence factors on the reduction factor were also investigated. The comparative study shows that the FS values obtained by the equivalent area model are higher than those by the individual column model. The results of these analyses are summarized into a series of design charts, which can be used in engineering practice. A reduction factor for FS of 0.90 is appropriate to convert the calculated FS by the equivalent area model to that by the individual column model based on the current study. Furthermore, the existence of the water table results in lower FS values than the cases without considering a water table because the groundwater reduces the shear strength of the improved foundation.
Computers and Geotechnics, 2009
ABSTRACT A multi-column composite foundation is a new concept utilizing different column types wi... more ABSTRACT A multi-column composite foundation is a new concept utilizing different column types with varying lengths and diameters to support the embankment fill and to mobilize the strength and stiffness of the soil at shallow depths. This study presents the results of finite element analyses using the finite element software PLAXIS to investigate the consolidation behavior of a road embankment constructed on a multi-column composite foundation. The finite element results are calibrated for a period of 200 days. The settlement, horizontal displacement, differential settlement, column axial force, and the development and dissipation of excess pore pressure are presented and discussed in detail. It is concluded that a multi-column composite foundation allows a fast rate of consolidation and significantly increases the embankment stability. A multi-column composite foundation formed by CFG–lime columns is more effective than one formed by SC–lime columns. The CFG–lime columns improve the long-term stability of the embankment because the compression modulus of CFG columns is significantly greater than that of SC columns.
Piled embankments provide an economic solution to the problem of constructing embankments over so... more Piled embankments provide an economic solution to the problem of constructing embankments over soft soils. The piles and geosynthetic combination can alleviate the uneven surface settlements that sometimes occur in embankments supported by piles without reinforcement. The main focus of this paper is to present a new method for analysis of an embankment of granular fill on soft ground supported by a rectangular grid of piles and geosynthetic. This method is based on consideration of the arching effect in granular soil and similar to the method proposed by Low, B.. The main refinements are: inclusion of a uniform surcharge load on the embankment fill, individual square caps were used, and taking into account the skin friction mechanism, which contributes to soil–geosynthetic interface resistance. Using this method, the influence of embankment height, soft ground depth, soft ground elastic modulus, and geosynthetic tensile stiffness on efficiency, stress concentration ratio, settlement ratio, tension of geosynthetic, and axial strain of geosynthetic are investigated. The results show that inclusion of a geosynthetic membrane can increase the fill load carried by piles. As a result, both the total and differential settlements of the embankment can be reduced. The new design method was verified against several current design methods. Theoretical solution showed that BS8006 [1995. Code of Practice for Strengthened/Reinforced Soils and other Fills. British Standards Institution, London, p. 162] and Guido, V.A., Kneuppel, J.D., Sweeny, M.A. [1987. Plate loading tests on geogrid-reinforced earth slabs. In: Proceedings of the Geosynthetics '87, New Orleans, USA, IFAI, pp. 216–225] methods overpredict the vertical stress acting on the geosynthetic due to that the reaction of the soft ground on the geosynthetic is not considered in their methods. It also showed that the present method is in good agreement with Low, B.
Cement–Flyash–Gravel (CFG) pile is a widely used ground improvement technique. A CFG–lime multi-p... more Cement–Flyash–Gravel (CFG) pile is a widely used ground improvement technique. A CFG–lime multi-pile composite foundation is a new concept utilizing CFG and lime piles. This study presents the results of finite element analyzes using ANSYS software to investigate the behavior of composite CFG–lime pile foundations under various load distributions. The parameters studied include the length and diameter of piles and the thickness of the cushion. The stress distribution beneath the composite foundation, the influence of the cushion on load-settlement behavior, and the ratio of stresses in the piles to those in the subsoil are also studied. The results show that settlement is much more significantly affected by the length and diameter of the CFG pile rather than that of the lime pile. This suggests that the CFG pile indeed acts as a settlement-reducing pile, which is in accordance with the working principle of such composite foundations. On the other hand, the load distribution between piles and subsoil is significantly affected by the cushion thickness.