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Accurate determination of the ultimate bearing capacity (UBC) of shallow foundations is vital for the safety of structures and buildings. Due to the inherent spatial variability characteristics of soil properties, some new approaches are needed to accurately determine the UBC of shallow foundations. The objective of this study is to develop a hybrid least squares support vector machine (LSSVM) and an improved particle swarm optimization (IPSO) algorithm for determining the UBC of shallow foundations. To validate the hybrid IPSO-LSSVM model, a comparison of the predictions was carried out among different models and theoretical methods. Three statistical indexes, namely the root-mean-square error (RMSE), the mean absolute error (MAE) and the correlation coefficient (R) were employed to measure and evaluate the performance of these models. The results showed that the developed hybrid IPSO-LSSVM model can be used for determining the UBC of shallow foundations with high accuracy. [ABSTRACT FROM AUTHOR]

Design of modern thin-walled metal structures is widely used around the world. In recent decades, more comprehensive research is carried out to investigate the behaviour of various thin-walled structures. Generally, the structure with regular geometry is investigated. In various countries such as USA, Russia, and the European Union issued the standards on regulation of the construction, design and maintenance of thin-walled structures. The actually used period of tanks usually is longer than recommendatory period. Recommendatory maintenance period of metal tanks is 15-20 years. Therefore, for such structures one of the most considerable questions is the residual load bearing capacity beyond the end of the maintenance period. This phase of using of structures is associated with complex investigation and numerical analysis of thin-walled structures. In this paper the load bearing capacity of the steel wall of the existing over-ground vertical cylindrical tank in volume of 5,000 m3 with a single defect and with a few contiguous local defects of the shape is analyzed. Calculations carried out are taking into account all the imperfections of the wall geometry. A major goal of the research - developing a realistic numerical model of the object analyzed, taking into account all the imperfections, determining the wall stress and strain state, exploring the places of extreme points, calculating the residual load bearing capacity of the tank and scrutinizing possible strengthening schemes for defective areas. [ABSTRACT FROM AUTHOR]

The process of selecting road maintenance technologies for the Pavement Management System (PMS) can use road pavement moduli of deformation as the substantiating information. Assessment criteria based on either pavement or base course moduli of deformation have strong empirical underpinning, since the stiff plate bearing testing (SPBT) is commonly used worldwide. This paper discusses potential practical applications of plate bearing test numerical simula- tion based on Falling Weight Deflectometer (FWD) deflection data, and theoretical model based on flexible pavement. It was proven that including a pavement model with stress dependency, the simulated second load-displacement curves meet reliably plate bearing in-situ test conditions for different layers of either subgrade or base courses of road pave- ment. This methodology is feasible by classifying technical condition of each lower layer of road pavement against requirements towards new pavements. [ABSTRACT FROM PUBLISHER]

In this study a limit equilibrium method is proposed to determine the bearing capacity of strip foundations on geosynthetic reinforced sand soils. A two-layered granular soil was foreseen to represent the loose in situ soil and the compacted fill above the reinforcement. First the modified bearing capacity factorsNqandNγwere derived for the two layered granular reinforced soil. The bearing capacities were also calculated for different reinforcement geometries and soil properties using Finite Element analyses. The bearing capacities obtained from Finite Element and Limit Equilibrium analyses were compared, it was seen a good agreement. Therefore, it was concluded that the new limit equilibrium method proposed in this paper for reinforced two-layered soils can be successfully used in calculating the bearing capacities of geosynthetic reinforced soils. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of single, double, and triple reinforcing layers on the bearing capacity ratio (BCR) of strip footing on a sand slope system. Seventy-two laboratory-loading tests were conducted on a stripfooting model on a reinforced sand slope. Moreover, this study illustrated the effects of the different parameters of two reinforcing layers on the bearing capacity of a double-reinforced sand slope. The BCR increased from 1.06 to 3.00 for single-reinforced slope soils, 1.09 to 7.73 for double-reinforced slope soils, and up to 8.00 for three-layered reinforced systems. For double-reinforced soil slopes, the most effective spacing between the two reinforcing layers is 0.3 B. [ABSTRACT FROM AUTHOR]

The article focuses on the method for evaluation of ultimate bearing capacity for a vibratory pile having acceleration data recorded during the tests. The simulation vibratory pile installation test was performed in the testing stand. Accelerations were recorded on the top of the simulation vibratory pile during the test. The static test was performed for the installed pile. After the review of rheological models of the base, the Smith rheological model was chosen for determination of bearing capacity of the vibratory pile as this model, the rigidity of the final element of the spring is modelled as the finite rigidity of the base. Between the base of the modelled pile and the soil, a finite interface element is used. The interface element transfers only compression but it does not transfer tension to the base rheological model. The general stiffness of spring's finite element in the chosen rheological model is determined from experimental data of the static pile test. During the modelling, the damping coefficients and the ultimate displacements (responses) of the pile's shaft and base, to which the friction element became active, were determined so that the modelled pile accelerations and displacement (response) would coincide as much as possible with measured accelerations and their calculated response. The modelled and measured accelerations and responses showed high similarity. [ABSTRACT FROM AUTHOR]