Performance Of Footings Research Articles

Effect of isolated footing on fly ash subgrade reinforced with PET bottles: An experimental and analytical study

The continuous and significant excavation of subsurface soil and rock for structural backfilling, impacts the environment negatively. The present study attempts on the exploitation of non-biodegradable and hard-to-dispose waste materials (in different capacities) such as fly ash (FA), rock quarry dust (RQD), and refurbished Polyethylene Terephthalate (PET) bottles were used as an alternative for structural backfill and reinforcement. For model testing, two phase novel methodology was proposed (Unreinforced and reinforced FA system). A total of 29 systems were examined, encompassing a broad range of boundary conditions like FA subgrade system, unreinforced FA system (FA + RQD) with varying RQD layer thickness “H”, and reinforced FA system (FA + RQD with PET bottle mattress as an interface between the FA subgrade and the RQD layer). The parameters pertaining to the reinforcement (width “b”) are varied with respect to the constant value of “H”. Loading was applied on isolated footings for both phases. The model testing demonstrates that the performance of footings resting on RQD laid over stabilized FA subgrade with PET bottle mattress as an interface outperforms other systems significantly. Optimum values for boundary conditions were obtained in case of both the systems. It is observed that in case of reinforced FA system with optimum boundary conditions, the bearing capacity was increased by 10 % and the RQD layer’s thickness was reduced by 47 % as compared to optimum values of an unreinforced FA system. Further, the optimized values of the phases were validated by using PLAXIS 3D software.

Therapy of Sensory Integration Disorders in Pre-School and Early School-Age Children (Based on the Results of Pilot Experimental Studies)

The concept of sensory integration, developed by Jean Ayres, is currently receiving considerable attention among specialists working with children experiencing developmental problems resulting from sensory integration disorders. Developmental problems arising from sensory integration disorders are exemplified, among others, in the acquisition of skills and abilities necessary for proper functioning, including those related to cognitive development and education. Therefore, during the course of the pilot experimental studies, presented in this article, an attempt was made to establish the effectiveness of plastic footbridges and those made with natural materials on the sensory integration therapy in pre-school and early school-age children. The studies concentrated on selected aspects of children’s functioning, including tactile performance of feet, motor coordination of the hands and legs with regard to gross motor skills, motor coordination of the hands with regard to fine motor skills, fitness and ability to maintain body balance. The research was carried out in four experimental groups: the first two groups included children of early school age with and without sensory integration disorders, and the other two included pre-school and early school-age children with deeper intellectual disabilities and sensory integration disorders. The two experimental groups carried out a series of five therapeutic classes using plastic footbridges, while two others used footbridges made of natural materials. The obtained data allowed a preliminary conclusion to be formulated about the superiority of footbridges made of natural materials over plastic footbridges in the context of effective influence on the therapy of sensory integration disorders in the examined children. However, it is necessary to continue research in more numerous groups and with a larger number of therapeutic classes.

Study on Behaviour of Two Adjacent Strip Footings on Unreinforced/Reinforced Granular Bed Overlying Clay with Voids

This paper numerically studies the behaviour of two adjacent strip footings on unreinforced and reinforced granular bed (RGB) overlying clay having voids. The influence of different parameters such as granular bed thickness, length of reinforcement/s, number of layers of reinforcement, presence of void/s beneath the footing/s in the weak soil, on the behaviour of footings are carried out in this study. It is found that there is a certain optimum spacing between the two adjacent strip footings at which the footing/s carry the maximum load. The voids could be formed in weak soil due to various reasons and the presence of voids may affect the performance of footings. Such voids tend to reduce the load carrying capacity of the footing/s. However, providing a RGB over weak soil can be used as an effective method to maintain the good performance of footings, even when voids could be formed in future.

Seismic Performance of Footings on Stone Columns Treated Dry Sand Beds

An extensive experimental study has been carried out to study the seismic performance of footings on stone columns treated dry sand beds. Physical models have been prepared in a laminar shear box of size 1 m3 on the shaking table which has a single degree of freedom motion for representing horizontal shaking action under seismic vibrations. Effect of the configuration of stone columns, aspect ratio of footing, relative density of sand bed, frequency and peak ground acceleration (PGA) of cyclic input motion on vertical settlement of footing has been studied. Optimum length of stone columns has been found to lie between 13–16 times the diameter. Direction of shaking perpendicular to length of footing has been found to be more critical. Effect of aspect ratio has been found to be more pronounced at larger PGA. Influence of the frequency on response of footings has also been quantified.

Study on Behaviour of Two Adjacent Strip Footings on Granular Bed Overlying Clay with a Void

This paper numerically examines the behaviour of two adjacent strip footings on granular bed over weak soil having a void. Voids could be formed in weak soil strata due to various reasons such as due to water leakage from the water supplying lines or sewer lines, poor drainage and erosion of soil, animal burrows, etc. A parametric study is carried out to understand the influence of granular bed thickness, width of footings, spacing between the footings, and the presence of a void beneath the footing in the weak soil, on the behaviour of footings. To understand the failure mechanism, shear strain contours, for different cases, are being studied. It is observed that there is a certain critical spacing between the two adjacent footings at which the footing/s carry the maximum load. This critical spacing depends on the type of loading, whether equal and simultaneous loading or unequal and sequential loading. The presence of voids also affects the performance of footings. Such voids tend to reduce the load carrying capacity of the footing/s and alter failure pattern.

Investigation of the Performance of Foot and Eye Care in Patients with Type II Diabetes in Fasa: An Application of the Theory of Planned Behavior

Investigation of the Performance of Foot and Eye Care in Patients with Type II Diabetes in Fasa: An Application of the Theory of Planned Behavior

Performance of circular footings on sand by use of multiple-geocell or -planar geotextile reinforcing layers

This paper describes a series of reduced scale tests, at unit gravity, performed on circular footings supported by reinforced sand. Reinforcement by multiple layers of geocell was investigated and the performance of the footing was compared to one on the same sandy soil containing multi-layered planar geotextile reinforcement. The comparison used geocell and geotextile layers formed from the same parent geosynthetic material having the same characteristics but with a lower geocell mass. Results show that the efficiency of the reinforcement (described in terms of the load carrying and subgrade modulus enhancement) decreased as the number of layers increased. In tests at moderate and low footing settlements, significant improvements in bearing capacity and subgrade modulus were obtained with the application of three layers of geocell. On the whole, multi-layered geocell-reinforced soil provides a more effective and much stiffer system capable of delivering greater foundation loads and subgrade modulus than multi-layered planar-reinforced soil, even when less parent geosynthetic material is used in the multi-layered geocell arrangement. Furthermore, reinforcement benefit is achievable at settlements as small as 0.2–0.4% of the footing diameter for the geocell installations, whereas settlements 4 to 5 times larger are needed before benefit is gained from a comparable planar geotextile system. To achieve comparable performances, the multi-layered geocell requires 1/4 to 1/2 the mass of geosynthetic material as that needed for multi-layered planar geotextile reinforcement (depending on the settlement allowable). The multi-layered geocell reinforcement requires considerably less parent geosynthetic material (reducing transport and, perhaps supply costs), and because the size of reinforcement zone required is considerably smaller, the amount of excavation and backfill required is also significantly reduced.

Laterality judgments in people with low back pain – A cross-sectional observational and test–retest reliability study

BackgroundDisruption of cortical representation, or body schema, has been indicated as a factor in the persistence and recurrence of low back pain (LBP). This has been observed through impaired laterality judgment ability and it has been suggested that this ability is affected in a spatial rather than anatomical manner. ObjectivesWe compared laterality judgment performance of foot and trunk movements between people with LBP with or without leg pain and healthy controls, and investigated associations between test performance and pain. We also assessed the test–retest reliability of the Recognise Online™ software when used in a clinical and a home setting. DesignCross-sectional observational and test–retest study. MethodsThirty individuals with LBP and 30 healthy controls performed judgment tests of foot and trunk laterality once supervised in a clinic and twice at home. ResultsNo statistically significant group differences were found. LBP intensity was negatively related to trunk laterality accuracy (p = 0.019). Intraclass correlation values ranged from 0.51 to 0.91. Reaction time improved significantly between test occasions while accuracy did not. ConclusionsLaterality judgments were not impaired in subjects with LBP compared to controls. Further research may clarify the relationship between pain mechanisms in LBP and laterality judgment ability. Reliability values were mostly acceptable, with wide and low confidence intervals, suggesting test–retest reliability for Recognise Online™ could be questioned in this trial. A significant learning effect was observed which should be considered in clinical and research application of the test.

Mapping Potential Risk for Housing Damage from Ground Movement Due to Climate Change

The performance of footings in residential construction is influenced by the degree of ground movement, particularly in reactive soils, which is driven by the magnitude of change in soil moisture. New patterns of climate are affecting residential foundations and causing serious and expensive damage. This paper produces a map of potential risk for housing damage from ground movement due to climate change. Using a geographic information system, it combines information on (1) soil moisture change related to climate, using TMI as the indicator, and (2) population growth. Preliminary results, having Victoria, Australia, in the last decade as the case study, suggest that effects of climate change on soil, and resulting impacts on house foundations, are not being taken into consideration in current planning strategies for urban development. Most of the urban growth priority zones in the study area are susceptible to medium and high risk for damage. Producing new and renovated buildings that are durable in the long term is essential for the economy, environment and social welfare. The map presented here can assist policies and strategies towards urban resilience in the context of climate change.

An Improved Experimental Test Set-up to Study the Performance of Granular Columns

Abstract This paper describes an innovative design of a newly developed large test setup for testing the performance of footings supported on soft clay reinforced with granular columns. This advanced testing method is used to examine the settlement of footings supported on granular columns. Two important features of the equipment are (a) the axial loading system which allows samples to be consolidated under Ko condition while the load is applied onto a small foundation area of the sample, and (b) a relatively large sample size of 300-mm diameter and 400-mm high. The system is also equipped with pressure cells located beneath the footing and top cap to measure the pressure distribution with respect to foundation displacement and a lateral strain gage to monitor boundary effects. This paper reports on some of the early findings from the preliminary tests carried out using this equipment. Samples for testing were prepared by consolidating kaolin slurry in a large one-dimensional consolidation chamber. The granular columns were installed using the replacement method by compacting crushed basalt (uniformly graded with 90 % between 1.5–2-mm particle sizes) into a preformed hole. The preliminary tests have yielded promising results, validating the functionality of the equipment and support the prospect of increasing the knowledge with respect to settlement response and design of a footing supported on granular columns.