Comparative study on the behavior of square foundations resting on confined sand

2009 ◽  
Vol 46 (4) ◽  
pp. 438-453 ◽  
Author(s):  
Hisham T. Eid ◽  
Omar A. Alansari ◽  
Abdelfattah M. Odeh ◽  
Mohannad N. Nasr ◽  
Husam A. Sadek

The behavior of shallow foundations resting on laterally and (or) vertically confined sand has been investigated using physical and numerical modeling. The models were designed to simulate the frequently constructed raft foundations that are surrounded by sheet-pile walls to support excavation sides of sand underlain by a rock bed. Laboratory tests were carried out utilizing a square foundation model surrounded by rigid steel walls with different depths, resting on sand that was underlain by a rough rigid layer. Varying sand-layer thicknesses and relative densities were utilized. A three-dimensional finite element analysis was conducted to verify the physical-model test results and to infer the performance of full-scale foundations. Based on the results of the experimental and numerical analyses, charts are presented to estimate the enhanced bearing capacity of square foundations resting on confined sand. These charts are presented in terms of bearing capacity of the surface foundation resting on extended sand, sand relative density, wall width to foundation width ratio, and rigid layer depth. Charts are also presented to estimate settlement reductions due to the bearing sand lateral and (or) vertical confinement.

2018 ◽  
Vol 175 ◽  
pp. 01036
Author(s):  
Xudong Hua ◽  
Xingwei Xue ◽  
Junlong Zhou ◽  
Hai Zhang

The actual bearing capacity of a bridge in active service is crucial to the structure, but such data is generally difficult to obtain. In order to obtain the actual ultimate bending capacity of the used hollow slab, a destructive test of a hollow slab, which has been used ten years, has been carried out. Moreover, based on the experimental analysis of the material parameter data, a three-dimensional finite element nonlinear analysis model of the used hollow slab was established. Through the experiment and finite element analysis of the used hollow slab, the comparisons of the failure mode, crack propagating and ultimate bending capacity were focused on. The main conclusions obtained through the study are as follows: (1) Strand is a kind of stable prestressed material, which can maintain good mechanical properties for a long time; (2) The used hollow slab still maintains good ultimate bending capacity, although underwent a decreased rigidity due to long-term cumulative damage; (3) The total strain fracture model is qualified for simulating the nonlinearity of concrete material, and can obtain the ultimate bearing capacity of reinforced concrete structure effectively as well as simulates the development of cracks well.


2014 ◽  
Vol 488-489 ◽  
pp. 689-695
Author(s):  
Shuai Liu ◽  
Wen Bai Liu ◽  
Liang Yang

The ABAQUS software is used for simulating the vertical bearing capacity of bucket foundation of different ratios of diameter to height and the analysis for the stress and displacement distribution and load-displacement curve. When the bucket foundation is under pressure, the vertical stress of the soil distribution changes from the bottom to the top, and then spreads to most part of the soil in the bucket foundation. The vertical displacement of the soil develops from the top of foundation and spreads inside, then expands to the outside range, the maximum displacement occurs both at the bottom and inside. According to the analysis of the ultimate bearing capacity of the bucket foundation, it could be found that when the height of the bucket foundation remains unchanged, the ultimate bearing capacity increases with the increasing ratio of diameter to height. If the ratio of diameter to height is less than 1.2, the ultimate strength increases significantly. If the ratio of diameter to height is greater than 1.2, the increasing speed of the ultimate bearing capacity changes slowly. When the diameter of the bucket foundation is constant, the ultimate bearing capacity decreases as the ratio of diameter to height gradually increases, and it decreases at a homogeneous speed. So the ratio of diameter to height 1.2 can be used as the optimum point of the ratio of diameter to height of the bucket foundation.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


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