Improvement In Bearing Capacity Research Articles

Bearing capacity improvement of shallow foundations using a trench filled with granular materials and reinforced with geogrids

Bearing capacity improvement of shallow foundations using a trench filled with granular materials and reinforced with geogrids

Design and experimental study of a buckling-restrained steel plate shear wall with novel buckling-restrained panels for improving bearing capacity and energy dissipation

In this study, a buckling-restrained steel plate shear wall with novel buckling-restrained panels (hereafter referred to as the BRSPSW-NBP) with improved bearing capacity and energy dissipation is proposed. The novel buckling-restrained panel comprises a concrete panel and load-bearing connection steel plates with energy dissipation segments. These steel plates are connected with the boundary frame through connectors for transferring the horizontal and vertical loads to the concrete panel. Therefore, the buckling-restrained panel serves as an additional load-bearing component that increases the bearing capacity and lateral stiffness of the BRSPSW-NBP. To dissipate seismic energy, the energy dissipation segments in the load-bearing connection steel plates are designed to undergo plastic deformation earlier than the inner steel plate such that the BRSPSW-NBP develops a multi-stage energy dissipation characteristic. Theoretical analyses were conducted to investigate the seismic behaviour of the BRSPSW-NBP. The bearing capacity and multi-stage energy dissipation characteristic of the BRSPSW-NBP were studied through quasi-static testing. The results demonstrated that the connection steel plates with energy dissipation segments share the horizontal and vertical loads of the BRSPSW-NBP and undergo plastic deformation earlier than the inner steel plate, thus improving the bearing capacity and energy dissipation performance of the BRSPSW-NBP.

Utilization of Coconut Shell Charcoal to Improve Bearing Capacity of Clay as Subgrade for Road Pavement

Road construction on clay causes many problems with road damage because clay has a low bearing capacity and a large swelling value. The soil stabilization method was used to improve clay soil characteristics by adding cement, lime, fly ash, or other stabilizing agents. One of the stabilizing agents used in this study is coconut shell charcoal. The purpose of this study was to analyze the effect of adding coconut shell charcoal to the CBR value and the swelling index on clay soil. In this study, the coconut shell charcoal used was 0%, 4%, 8%, 12%, and 16% of the dry weight of the soil. The samples used were disturbed soil, and the curing period was 7 days. Testing the physical and mechanical properties of the soil (CBR and Swelling test) refers to the ASTM Standard. The results showed that the addition of coconut shell charcoal by 4% increased the bearing capacity and reduced the swelling index. An optimal CBR value of 14.69% was obtained for the addition of coconut shell charcoal by 4% with the unsoaked condition with a 7-day curing period. Whereas in the soaked soil condition, the optimal CBR value is 8.53% and the swelling value is 0.24%. Increasing the CBR value and decreasing the swelling value will cause the road construction layer to be more stable in supporting the load.

Improving bearing capacity of weak soils: A review

Weak soils, such as soft clay and loose sand, have a poor bearing capacity, making them incapable of bearing the load of superstructures that will be imposed on them. As a result, engineers must have a solution to the issue of poor bearing capacity in weak soils before embanking into building on them. This paper reviewed the use of stone columns, piled rafts, and geogrids for improving the bearing capability of weak soils. Important findings from recent research are also discussed. From the review of the previous researcher’s findings, it was found that modelling approaches such as physical modelling (full scale, centrifuge, laboratory scale) and numerical modelling are used to study bearing capacity improvement.

Improving Bearing Capacity by Skirted Foundation: A Review Study

The difficulty that faces the geotechnical engineers how to find the alternative and effective method to improve bearing capacity and reduce foundation settlement. Therefore, the skirt is considered one of the methods to improving the shallow foundation bearing capacity on different soil. The mechanism of skirt work is confinement soil below the foundation and decrease settlement of the foundation. Soil engineers are worked to devise this method as an alternative to pile foundation for conventional buildings. This paper reviews most of these studies of skirted foundations with different types of soil including laboratory tests, field tests, centrifuge models, numerical method and theoretical analysis; these studies are used in investigation the behaviors skirted foundations.

Compressive behavior and modelling of engineered cementitious composite (ECC) confined with LRS FRP and conventional FRP

A combination of core engineered cementitious composite (ECC) and external fiber-reinforced polymer (FRP) composites can solve the problems of insufficient ductility and durability of normal concrete (NC) in adverse environments and improve bearing capacity. However, existing studies on the performance of ECC strengthened by FRP are very limited—particularly the research on large rupture strain (LRS) FRP-confined ECC. In this study, an experimental investigation of LRS FRP and conventional glass FRP-confined ECC cylinders with different confinement levels under axial compression is presented. It is found that the application of external FRP jackets leads to a significant improvement in the compressive strength and deformation of the core ECC. LRS FRP-confined ECC exhibits a higher ultimate deformation than conventional FRP-confined ECC. The dilation behavior, axial stress–strain behavior, and energy dissipation capacity between FRP-confined ECC and FRP-confined NC under the same confinement level are compared, and the former exhibits a significantly larger ductility and energy dissipation capacity than the latter. The results also indicate that most existing models are unable to accurately predict the compressive behavior of FRP-confined ECC. To address this, a dilation model and an axial stress–strain model of FRP-confined NC are modified to extend their application to FRP-confined ECC.

Effects of groove-textured surfaces with Sn-Ag-Cu and MXene-Ti3C2 on tribological performance of CSS-42L bearing steel in solid-liquid composite lubrication system

To expand the applications of MXene-Ti3C2 in solid-liquid lubrication system, CSS-42L smooth surfaces (SSs), groove surfaces (GSs), groove with Sn-Ag-Cu composite surfaces (GSs-SAC) and groove with Sn-Ag-Cu-Ti3C2 composite surfaces (GSs-SACT) are prepared. The tribological behaviors of samples under dry friction and oil lubrication are studied. The results show that Sn-Ag-Cu-Ti3C2 has the excellent oil film adsorption capacity. The micro-hydrodynamic effects of oil in the grooves are produced under oil lubrication. The synergistic effects of oil, Sn-Ag-Cu-Ti3C2 and grooves reduce the fluctuation amplitudes of friction force and load, improving bearing capacity of oil film and profile characteristics on the surfaces. GSs-SACT with uniform and smooth profiles shows the tribochemical wear and obtains the excellent antifriction and wear resistance properties.

A Parametric Study on Pavement with Geocell Reinforced Rock Quarry Waste Base on Dredged Soil Subgrade

Dredging produces a vast amount of waste from water bodies worldwide, whose valorization is an environmental problem. Weak dredged soil requires some treatment to provide them with adequate strength for construction applications. In the present study, static plate load tests are conducted to understand the effect of high-density polyethylene geocell reinforcement on limestone aggregates and quarry waste on subgrade (dredged soil). Finite element analysis was carried out to compare the results with the experimental analysis. The dolomitic limestone and crushed quarry waste are waste materials readily available in the near vicinity. Static plate load tests were observed for three different geocell heights (100, 125 and 150 mm) in terms of increase in bearing capacity and vertical stress distribution for three different thicknesses of bases (120, 150 and 170 mm). This study aims to present the results in terms of load versus deformation and vertical stress distribution. The results showed that the reinforced layer had undergone a maximum reduction in deformation in comparison to the unreinforced bases. Due to the inclusion of geocell, the average bearing capacity improvement factor enhances, and the vertical stress distribution increases significantly. The average bearing increases by 50% in the case geocell reinforced test section. The results from this study suggest that rock quarry waste can be used as an alternative base material for pavement construction if proper geocell confinement is provided. The present study results will be used as a reference to support that valorization of waste can be beneficial for both nature and the economy.

Geogrid bridging over existing shallow flexible PVC buried pipe – Experimental study

Protecting existing utility lines in congested urban centers is considered a major challenge especially in cases of new construction bridging over these lifelines. Several innovative techniques have been proposed lately to bridge over existing pipes. This study discusses the use of stiff three-dimensional geogrids to reinforce sandy soils bridging over existing buried Polyvinyl Chloride (PVC) pipe at shallow depth subjected to strip static loading. Twenty-eight large scale laboratory tests were conducted with variable geogrid geometries using single and double layers of geogrid reinforcement. Tests were heavily instrumented to record longitudinal and transverse strains in the pipe wall and geogrids, pipe deflections, pressures within the soil and above the pipe crown, and footing settlement. Optimization of the geogrid geometry was conducted in order to reduce strains and stresses in the PVC pipe subjected to static loading. In general, introducing the geogrid reinforcement has reduced stresses transferred to the pipe crown below the center of the loading. For a given applied stress, the increase in geogrid width has resulted in a reduction in stress transferred to the pipe and longitudinal strains developed in the pipe. Up to 80% reduction in longitudinal strains was observed in the PVC buried pipe as a result of the geogrid reinforcement. Finally, the results have shown up to 150% improvement in soil bearing capacity and nearly 50% reduction in surface settlement as a result of introducing geogrid reinforcement. The main finding in this study is that three-dimensional geogrid reinforcement was effective in reducing the longitudinal strains in existing PVC shallowly buried pipes subjected to static loading.

Bearing capacity of E-shaped footing on layered sand

Purpose: The purpose of this study is to estimate the ultimate bearing capacity of the E-shaped footing resting on two layered sand using finite element method. The solution was implemented using ABACUS software. Design/methodology/approach: The numerical study of the ultimate bearing capacity of the E-shaped footing resting on layered sand and subjected to vertical load was carried out using finite element analysis. The layered sand was having an upper layer of loose sand of thickness H and lower layer was considered as dense sand of infinite depth. The various parameters varied were the friction angle of the upper (30° to 34°) and lower (42° to 46°) layer of sand as well as the thickness (0.5B, 2B and 4B) of the upper sand layer. Findings: The results reveal that the dimensionless ultimate bearing capacity was found to decrease with the increased in the H/B ratio for all combinations of parameters. The dimensionless ultimate bearing capacity was maximum for the upper loose sand friction angle of 34° and lower dense sand friction angle of 46°. The results further reveal that the dimensionless bearing capacity of the E-shaped footing was higher in comparison to the dimensionless bearing capacity of the square footing on layered sand (loose over dense). The improvement in the ultimate bearing capacity for the E-shaped footing was observed in the range of 109.35% to 152.24%, 0.44% to 7.63% and 0.63% to 18.97% corresponding to H/B ratio of 0.5, 2 and 4 respectively. The lowest percentage improvement in the dimensionless bearing capacity for the E-shaped footing on layered sand was 0.44 % at a H/B = 2 whereas the highest improvement was 152.24 % at a H/B = 0.5. Change of footing shape from square to E-shaped, the failure mechanism changes from general shear to local shear failure. Research limitations/implications: The results presented in this paper were based on the numerical study conducted on E-shaped footing made out of a square footing of size 1.5 m x 1.5 m. However, further validation of the results presented in this paper, is recommended using experimental study conducted on similar size E-shaped footing. Practical implications: The proposed numerical study can be useful for the architects designing similar types of super structures requiring similar shaped footings. Originality/value: No numerical study on E-shaped footing resting on layered sand (loose over dense) were conducted so far. Hence, an attempt was made in this article to estimate the bearing capacity of these footings.

Field test research on post-grouting effect for super-long cast-in-place bored pile in thick soft foundation

The field static load test method was adopted for two test piles in a project in Zhejiang area of China, analyze the effect of post-grouting technique on super-long cast-in-place bored pile and its internal mechanism. Q-s curves and pile axial force curves were drawn based on test data to show that post-grouting technique played a prominent role in improving bearing capacity of single pile and pile skin friction. In addition, pile skin friction at upper soil layer around super-long pile was fully used, but that at lower soil layer was not. For the design of super-long pile, the compression of pile body should be considered to make the best use of pile skin friction caused by relative displacement between pile and soil.

Effect of soil saturation conditions and helical configurations on compression capacity of screw piles

Helical piles provide many advantages over other conventional piles system. Most studies focuses on the performance of these piles in the dry and fully saturated soils. Rare studies are curried out to evaluate the performance of helical piles in partially saturated soils. Small scale models of steel piles of 600mm length with single, double, and triple helices have been embedded in cohesion less soil a depth of 400mm, the inner pipe diameter (d) was 20 mm and the helix diameter (D) was 50mm with spacing between helices of 3D, (i.e wing ratio (S/D) of 3). The models were tested using different soil saturations conditions (dry, fully saturated, and partially saturated soils). A pipe pile model was tested as a reference for bearing capacity improvement ratio. The results showed that the helical pile models and the pipe pile in fully saturation condition have less ultimate capacity compared to other soil conditions. The increment of bearing capacity increased for partially saturated soils than that of fully saturated soil by 1.5 to 1.8 times. The percentage of improvement of bearing capacity for additional helices single double and triple, embedded within fully saturation soil were 33.3%, 45.0% and 108.3% respectively, than shaft pile only.

Stabilization of Black cotton soil using Fly ash

Expansive Black cotton clay soils are widely distributed worldwide, and are a significant damage to infrastructure and buildigs. It is a common practice around the world to stabilize black cotton soil using fly ash to improve the strength of stabilized sub- base and sub grade soil. Soil stabilization is the improvement of strength or bearing capacity of soil by controlled compaction, proportioning or addition of suitable admixtures or stabilizers. The Black cotton soils are extremely hard when dry, but lose its strength fully when in wet condition. In monsoon they guzzle water and swell and in summer they shrink on evaporation of water from there. Because of its high Swelling and shrinkage characteristics the black cotton soils has been a challenge to the highway engineers.So in this research paper fly ash has been used to improve the various strength properties of natural black cotton soil.The objective of this research paper is to improve the engineering properties of black cotton soil by adding different percentage of fly ash by the weight of soil and make it suitable for construction. A series of standard Proctor tests (for calculation of MDD and OMC) and California Bearing Ratio (C.B.R) tests are conducted on both raw Black cotton soil and mixed soil with different percentages of fly ash (5%, 10%, 20%, 30%) by weight. A comparison between properties of raw black cotton soil, black cotton soil mixed with fly ash are performed .It is found that the properties of black cotton soil mixed with fly ash are suitably enhanced.

Effect of Spacing between Stone Columns on the Behavior of Soft Soil

Soil improvement by stone columns is extensively used, especially for the soft ones. This is because of their efficiency and no environmental impact. Several factors affect its efficiency in improving the mechanical properties of the soil, and the most important of these factors are the spacing, length, and diameter of the stone columns. In this study, the finite element method was used to study the impact of the spacing between the stone columns on the amount of settlement and the bearing capacity of the soil. The study comprises three different spaces (s) that were taken in relation to the columns’ diameter (d), which are (s/d= 3, 4, and 5). In addition, three types of the sectional shape of column involved circular, rectangular, and square sections with different lengths of (L/d=2, 4, 6, 8, and 10). The results showed that the spacing between the stone columns is effective when the vertical load is greater than 30 kN/m2, and below this, there is no effect of the spacing. In general, the settlement decreases, and the bearing capacity increases with the decrease in the spacing between the stone columns. The spacing becomes a more pronounced effect with the longer length of the stone columns. All sections of the stone columns with a short length of (L/d=2) showed the same settlement of 271 mm at a distance (s/d=5), which decreases by 7.4, 6.6, and 8.9% at a distance (s/d=3) for the circular, rectangular and square sections respectively. In the case of long columns (L/d=10), the settlement at (s/d=3) improves by about 27.5% which drop to about 18% at (s/d=5). A slight improvement in the soil's bearing capacity is associated with decreases in the spacing between the stone columns. The improvements in the bearing of soil treated with short columns (L/d=2) are 6.0, 6.5, and 4.7% for circular, rectangular, and square sections, respectively, when changing the distance from (s/d=5) to (s/d=3). Whereas they become greater when increasing the columns’ length to (L/d=10) to be 7.9, 9.2, and 6.4%.

Performance evaluation of construction and demolition waste aggregates as an alternative base course material in highway construction

ABSTRACT Construction and demolition (C&D) wastes are found to be the main source of unwanted materials produced worldwide. Due to the insufficient amount of high-quality fresh limestone aggregates, construction and demolition waste are used as an alternative base course material for highway construction. The stabilization of C&D recycled aggregate waste with ordinary portland cement (OPC) has been repeatedly used by the researchers to improve the performance of the base course in highway construction. The studies related to the geosynthetic-reinforced C&D waste are limited. In this study, the efficacy of geosynthetics reinforced bases was evaluated within the base course with three different base thickness (120, 150 and 200 mm). Two different infill materials, namely, C&D waste and limestone aggregates were used and plate load tests were conducted to simulate traffic loading over geosynthetic reinforced and unreinforced unpaved test sections. This study aims to present the results in terms of load versus deformation and load versus vertical stress distribution. It was observed that the C&D waste improvement factor is more than virgin aggregates (limestone aggregates). Due to the inclusion of geocell and geotextile, the average bearing capacity improvement factor enhances by 62% and the vertical stresses decrease significantly.

Bearing Capacity and Settlement Response of Ordinary and Geosynthetic Encased Granular Columns in Soft Clay Soils: Analysis and Design Charts

This paper discusses the bearing capacity and settlement response of granular columns with and without geosynthetic encasement using the currently available design procedure. The design procedure is modified to include the influence of the geosynthetic encasement. The key parameters influencing the load bearing capacity and settlement are studied through comprehensive parametric analyses. The results portray the advantage of geosynthetic encased granular columns in enhancing the bearing capacity and reducing the settlements compared to granular columns without encasement. Different installation patterns of granular columns were considered in this investigation. The maximum bearing capacity improvement and settlement reduction are observed with granular columns installed in triangular plan arrangement. The hexagonal pattern results in the lowest area replacement ratio and also the lowest improvement factors. It is shown that with geosynthetic encasement, the performance with hexagonal pattern could be improved to match with other more efficient patterns like square and triangular. Some selected results are validated through detailed finite element results. A quick assessment of the settlement improvement with geosynthetic encapsulated granular columns is possible with the design charts presented.

Intrusion of Geomesh in Gypseous Soil Under Single Footing

Methods to improve bearing capacity of footing resting of collapsing soil can, in fact, take two approaches, improving soil strength properties and intrusion of reinforcing sorces into soil. The footing is modeled by a square steel plate 0.1 by 0.1 m. The footing is loaded as to have a stress of 40 kPa and settlement is receded in dry and in soaking conditions. Two depths of the geo-mesh reinforcement are used, one B (B is width of footing) and 0.5B. For one B depth, three different square sizes of geo-mesh are used, 4B, 6B, and 8B. For the reinforcement depth of 0.5B the three sizes of the geo-mesh used are, 3.5B, 5.5B, and, 7.5B. Results reveal that the best improvement obtained is the case of square geo-mesh width of 7.5B and located at depth of B/2 under footing, with an improvement in terms of collapse settlement of 35%, and a settlement reduction in dry condition of 50%. The least improvement is the case of square geo-mesh with width of 4B and depth of one B, and it was really negligible, about 4% decrease in collapse settlement. Other cases varied between the two mentioned ratios. For findings of study, author recommends not to use geomesh size less than size of footing and not to place it in a depth more than half footing width. As such, in a whole, the effectiveness of geomesh in reducing the settlement of collapsing soil is obvious if used in proper way.

Peat Soil Improvement Method Using Woven Bamboo and Cerucuk

Most of the land in South Sumatera is the problematic soil, one of that is peat. Peat has low soil bearing capacity, and it becomes a problem when construction is built. Before the installation process, it is necessary to handle that soil. Soil improvement that can be done on peat to increase the bearing capacity value is the reinforcement method or physical stabilization. The results of research on woven bamboo and cerucuk are used as reinforcement material, which is expected to be an alternative to improve soil bearing capacity. The research methodology used was on the scale of the laboratory and analyzed by comparing the soil bearing capacity without reinforcement in bearing capacity ratio (BCR). The maximum bearing capacity with cerucuk reinforcement and without woven bamboo is 39.33 kPa with variations of the two outer rods of the left and right sides from 750 angle toward the foundation plane. However, using the 3 layers of reinforcement woven bamboo that is combined with cerucuk, which has diameter 1,5 cm and length 60 cm generates the highest soil bearing capacity value. The maximum of bearing capacity is 58 kPa. The BCR is 10,88 or in percentage is 988,2%, or 10 times greater than bearing capacity without reinforcement. So, it can be inferred that woven bamboo and cerucuk are used as an alternative to improve bearing capacity on peat soil.

Effect of Multi-Directional Reinforcements on the Settlement and Heave Characterstics of Foundations on Sand

Laboratory plate load tests are conducted on model footings resting on sand bed reinforced with plastic multi-directional reinforcements. The bearing capacity, settlement and heave are evaluated and the effect of depth to first layer, spacing between reinforcements in a layer, number of layers and spacing between layers are investigated. The bearing capacity at 25 mm settlement improved by almost 1.3 times for a single layer of reinforcement, placed at an optimum depth of 0.5B. An increase in number of layers beyond four resulted in a reduction in improvement of bearing capacity. Three layers of reinforcement, spaced vertically apart at 0.5B resulted in a maximum increase of 185% in the bearing capacity. For the same area, the multi-directional reinforcing elements provide additional confinement to the soil mass due to the three dimensional projections. Comparing the economic aspects, the multi-directional elements prove to be a viable alternative to the conventional planar geosynthetics. An artificial neural network based model has been developed in order to effectively predict the ultimate bearing capacity and settlements of the model footing, resting on reinforced sand.

Effect of geosynthetic reinforcement on the bearing capacity of strip footing on sandy soil

Due to the increasing presence of problematic soils, expansive clays and highly compressive sand engineers are using a verity of soil improvement techniques to treat such soils. While geosynthetics are extensively used for improving soil characteristics in roads, pavements and embankments, it can also be used to increase the lack of bearing capacity of residential housing or lightweight structures constructed on sandy soils. In order to simulate site conditions in the laboratory environment, a laboratory-scale testing platform has been manufactured to assess the behaviour of geosynthetics reinforced and un-reinforced strip footing. The first group of tests were performed on the unreinforced compacted sandy soils with different densities where the other group of tests were carried out in the soil that has been reinforced individually with three different types of geosynthetic materials having distinct tensile strengths. Furthermore, interface direct shear tests and consolidated undrained triaxial tests have been carried out to determine the shear parameters which is directly influencing the bearing capacity a strip footing. Geosynthetic reinforcement has considerably enhanced the mechanical behaviour of sandy soil in regarding the type of geosynthetic. Furthermore, it was observed that coir geosynthetic has provided increased interfacial friction when compared to other geosynthetic types and improved bearing capacity. Moreover, the adopted testing method found to represent well the behaviour of such materials in the laboratory environment.