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Item A Numerical Study on Interference Effects of Closely Spaced Strip Footings on Cohesionless Soils(Springer Science and Business Media Deutschland GmbH, 2021) Anaswara, S.; Shivashankar, R.Foundations of buildings often need to be placed at close spacings to meet the various structural or functional requirements. In such cases, the combined action of adjacent footings is different from that of a single foundation. The combined effect causes interference of the stress zones. Numerical analysis is carried out on two closely spaced strip footings on sands, by varying the affecting parameters, to study the interference effects. Interference effects are analysed in terms of bearing pressure, settlement and tilt of foundations. In this study, the interference effects of closely spaced strip footings on the surface of cohesionless soils are being investigated. Parametric studies are done for two foundations by varying the clear spacing between the foundations. The results are presented in terms of interference factors. New structures near to the old construction may alter the settlement, pressure and rotational characteristics of the old footing and could lead to its distress. Above all, the load-carrying capacity of the new foundation will be very different from what it would have carried if it were independent—without the interference of the other footing. First footing representing an already existing footing is loaded with half of the estimated failure load of single independent strip footing and second adjacent footing loaded up to failure. The effect of interference of the old foundation is observed to be particularly significant in terms of the settlement and tilt. © 2021, Springer Nature Singapore Pte Ltd.Item Studies on Tilt of Closely Spaced Strip Footings on Unreinforced and Reinforced Sands(Springer Science and Business Media Deutschland GmbH, 2021) Anaswara, S.; Shivashankar, R.Two or more strip footings are quite often built close to each other, due to which there will be overlapping of stresses in zones or at points between the footings. There is a non-uniform pressure distribution in the foundation soil beneath the footings, in the space between the footings and beyond. There is also an increase in confining pressure of the soils between the footings. All these result in the tilt of the footings. This numerical study looks into the tilt of the already existing strip footings due to the construction of an adjacent new strip footing on the surface of cohesionless soils. A parametric study is conducted including the effect of geogrid reinforcement/s beneath the new footing. One of the footings representing an already existing foundation is loaded with half of the estimated failure load of a single-strip footing, and adjacent new strip footing is loaded up to failure. The property boundary line is assumed to be midway between the two footings. Geogrid reinforcement layers beneath the new footing are considered to be extending equally beyond the footing on either side, up to the property line. Both unreinforced and reinforced sands are considered beneath the new footing for analyses. Tilts are observed to increase with the width of footing. At closer spacings, tilt was found to be more in case of loose sand. Results of this study indicate that there is a considerable increase in the tilt of the old footing in the presence of reinforcements beneath the new footing. © 2021, Springer Nature Singapore Pte Ltd.