Load Carrying Capacity Of Footing Research Articles

Influence of Geometrical Parameters of Geocell Reinforcement on the Load Carrying Capacity of Footing

Influence of Geometrical Parameters of Geocell Reinforcement on the Load Carrying Capacity of Footing

The Effect of Geotextile Layers and Configuration on Soil Bearing Capacity

The term "reinforced soil" refers to a composite material with high tensile-strength components that enhance the soil's tensile strength. One of the most common kinds of geosynthetic fabric utilized for soil reinforcement is geotextiles. This article investigates woven geotextile's potential benefits in enhancing the maximum load-carrying capacity of footings resting upon silty sand soil. The foundation was constructed of a 10 mm thick strong carbon steel plate of 100 mm×100 mm. The factors examined in this research were the first geotextile layer's depth, the geotextile layer's width, the number of layers of reinforcing material, and the vertical spacing between geotextile layers. The impact of geotextile strengthening configurations on the load-carrying capacity of strengthened soil foundations was also studied. The results of the experiments indicated that geotextile reinforced soil could help to grow the soil bearing capacity. The testing findings revealed that the system with three geotextile layers, 0.25B vertical distance among geotextile layers, and a geotextile width of 5B, B denotes the plate's width, achieves the most significant bearing capacity. The test findings also revealed that the reinforcement configuration greatly impacted the reinforced silty sand on the foundation's behavior.

Numerical investigation for strengthened RC footings with square concrete jacketing

Strengthening of existing isolated footings using concrete jacketing is a traditional method to increase the load-carrying capacity and to enhance the performance of isolated footings. This paper presents a parametric study and a numerical validation for full-scale square footings strengthened with concrete jacketing, using either dowels and bonding agent or bonding agent only, to connect the existing and new concrete surfaces. A nonlinear finite element program “ABAQUS” was used for the numerical validation and the parametric investigation for various parameter's effect on the load-carrying capacity and contact stress redistribution underneath the strengthened footings. The parameters used in the parametric analysis include the ratio of the concrete jacket depth to the concrete footing depth, concrete compressive strength, spacing between dowels, and the ratio of the concrete jacket width to the concrete footing width. The effect of dowels on load carrying capacity of footings strengthened using a full concrete jacket is insignificant for jacket width smaller than the footing width. In footing strengthened using a full concrete jacket, the load carrying capacity increases by 9% compared to the non-strengthened footing.

Groundwater Effect Factors for the Load-Carrying Behavior of Footings From Hydraulic Chamber Load Tests

Abstract The presence of groundwater level (GWL) causes changes in stiffness and strength of soil, affecting the bearing capacity and settlement of shallow foundations. In the present study, the load-carrying capacity and settlement of footings in sands under various GWL conditions were investigated. For this purpose, a series of model footing load tests and cone penetration tests (CPTs) were conducted using the hydraulically controlled chamber system. Different GWL and soil conditions were considered in the tests. The load-carrying capacity of footings became lower with increasing GWL, which was most significant within the depth of GWL (dw) equal to footing width (1.0B). Larger reductions in the bearing capacity with GWL were observed for looser soils with lower relative density. Based on the test results, design equations and correlation parameters for the GWL effects on the bearing capacity and settlement were proposed as a function of GWL, applied load, and relative density. It was confirmed that the existing CPT-based correlations to footing bearing capacity are valid and applicable for soils with GWL.

Strength of reinforced concrete footings without transverse reinforcement according to limit analysis

Isolated footings are reinforced concrete elements whose flexural and punching shear strengths are usually governing for their design. In this work, both failure modes and their interaction are investigated by means of the kinematical theorem of limit analysis. Previous works in this domain have traditionally considered failure mechanisms based on a vertical penetration of a punching cone. In this work, two enhanced failure mechanisms are investigated considering not only a vertical penetration of the punching cone, but also a rotation of the outer part of the footing, allowing to consider the role of both bottom and top reinforcements on the failure load. A rigid-plastic behavior with a Mohr–Coulomb yield criterion is considered for the concrete and a uniaxial rigid-plastic behavior is assumed for the reinforcement bars. The analysis shows that a smooth transition between flexural and punching shear failure occurs, corresponding to a flexural-shear regime. With respect to the punching shear failure regime, it is shown that the top reinforcement might play an important role (a fact usually neglected by previous investigations). Simplified formulations, allowing easy calculation of the load carrying capacity of footings, are derived and compared to the solutions according to limit analysis. Both theoretical and approximated solutions are finally compared with experimental results, showing consistent agreement.

A STUDY ON THE PERFORMANCE OF CIRCULAR FOOTING EMBEDDED IN GEOGRID REINFORCED FLYASH BEDS UNDER CYCLIC LOADING

The concepts of reinforced soil foundation (RSF) have been widely used in various geotechnical engineering applications. Most of the research work has been carried out by making use of frictional soil as a backfill material and fewer attempts have been made by making use of fly ash as backfill material. In the present study fly ash is used as a backfill material. This study highlights the performance of circular footing resting in reinforced fly ash beds under repeated loads. A series of tests were conducted on embedded circular footing resting on polyethylene geogrid reinforced fly ash beds under repeated loading. The experimental results demonstrated that the fly ash can be used as a backfill material in place of any other frictional fill. This is indicated by the higher load carrying capacity of footings resting in fly ash reinforced beds.

Experimental estimate of Nγ values and corresponding settlements for square footings on finite layer of sand

Any structure constructed on the earth is supported by the underlying soil. Foundation is an interfacing element between superstructure and the underlying soil that transmits the loads supported by the foundation including its self weight. Foundation design requires evaluation of safe bearing capacity along with both immediate and long term settlements. Weak and compressible soils are subjected to problems related to bearing capacity and settlement. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. A number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footings. The reliability of any theory can be demonstrated by comparing it with the experimental results. Results from laboratory model tests on square footings resting on sand are presented in this paper. The variation of bearing capacity of sand below a model plate footing of square shape with variation in size, depth and the effect of permissible settlement are evaluated. A steel tank of size <TEX>$900mm{\times}1200mm{\times}1000mm$</TEX> is used for conducting model tests. Bearing capacity factor <TEX>$N_{\gamma}$</TEX> is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesic's <TEX>$N_{\gamma}$</TEX> values. From the experimental investigations it is found that, as the depth of sand cushion below the footing (<TEX>$D_{sc}$</TEX>) increases, ultimate bearing capacity and settlement values show an increasing trend up to a certain depth of sand cushion.

Finite Element Study Using FE Code (PLAXIS) on the Geotechnical Behavior of Shell Footings

This study describes a study on the geotechnical behavior of shell footing using a non-linear finite element analysis with a finite element code, PLAXIS. The shell footing is found to have a better load carrying capacity compared with the conventional slab/flat footing of similar cross sectional area. The FE analysis also showed a reasonably good agreement with the laboratory experimental results. The effect of adding edge beams at the bottom of the shell footings has been studied numerically and found to be beneficial in increasing the load carrying capacity of the footing. The effect of increasing the embedment ratio is found to increase the load carrying capacity of the shell footings