Design Of Footings For Tilt-Up Panels At Boundaries

When a traditional shallow and wide footing is provided for tilt-up construction along the boundary of a property, the centreline of the footing falls on the inner side of the tilt-up panel thereby introducing a large moment due to load eccentricities. It is beneficial to provide a narrow and deep footing for tilt-up panels on a boundary for optimum utilisation of space. This study investigates the moment capacity of such footings with due consideration of the additional resistance provided by soil pressures on the vertical faces of the footings. A method for prediction of moment capacity was developed for narrow and deep footings that are subjected to eccentric loads. Three footings were tested at a construction site to develop the required insight for comparison of the failure load from field tests with the allowable load from the suggested method. Significant increase in eccentric load carrying capacity is possible if the resistance to moment due to the soil pressures on the vertical faces are included in the design equations. The suggested method to predict the allowable load of such footings for a given eccentricity is briefly outlined.