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1.
Introduction
In the literature several reports can be found dealing with soil-structure interaction problems, little to none was found dealing with the respond of the structure to the differential settlement of its foundation. While foundation settlement can be predicted at the design stage (Griffiths and Fenton, 2009; Mohamed et al. , 2013), often excessive and uncalculated settlements may occur during the lifespan of the structure. This is mainly due to changes in the loading and environmental conditions, to include; new construction in the neighboring area (Zhu et al. , 2012; Anastasopoulos, 2013; Camos et al. , 2014), deep excavation (Laefer et al. , 2009; Son and Cording, 2011), excessive flooding, or earthquakes (Bray and Dashti, 2014).
In design manuals, values for the allowable differential settlements were recommended for certain types of structures (Meyerhof, 1947; Zielinski et al. , 1980; Dulacska, 1992). Hanna et al. (1981) and Hanna (2003) examined the effect of differential settlement on high-rise reinforced concrete buildings. They suggested a guideline for assuming the allowable differential settlement for a given structure. Lin et al. (2015) investigated the performance of a ten-storey reinforced concrete building subjected to a differential settlement of its foundation of 25 mm. They reported that within the range assumed, the structure behaved elastically and the differential settlement has significant effects on bending moment in the structure members.
The current practice for the design of building structures in North America, as stipulated in the National Building Code of Canada (NBCC) (NRCC, 2010), does not account for the effects of the differential settlement of its foundation. However, design manuals propose an allowable differential settlement of 0.75 inch (ACI, 1992) for classic structures, which is believed to be tolerated by the factor of safety of the structure.
It is then paramount for foundation and structure engineers to examine the consequences and the remedy of excessive differential settlement on buildings (Boone, 1996; Kim et al. , 2011). It should be made clear that the higher the differential settlement, the lower the cost of the foundation and the higher the additional stresses induced in the superstructure, and accordingly, the higher the cost of the building and vice versa. Given this, a trade-off between the superstructure and its foundation during the design stage should...