American Society of Civil Engineers


Partial Loss of Support and Frame-Soil Interaction


by Mehter M. Allam, (Lect., Dept. of Civ. Engrg., Indian Inst. of Sci., Bangalore, India), Kanakapura S. Subba Rao, (Prof., Dept. of Civ. Engrg., Indian Inst. of Sci., Bangalore, India), and B. V. V. Subramanya, (Res. Scholar, Dept. of Civ. Engrg., Indian Inst. of Sci., Bangalore, India)

Journal of Structural Engineering, Vol. 113, No. 12, December 1987, pp. 2488-2499, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9445(1987)113:12(2488))

     Access full text
     Permissions for Reuse  

Document type: Journal Paper
Abstract: An interaction analysis has been conducted to study the effects of a local loss of support beneath the beam footing of a two-bay plane frame. The results of the study indicate that the magnitude of increase in the bending moment and axial force in the structure due to the presence of a void are dependent, not only on the extent of support loss, but also on the relative stiffnesses between foundation beam and soil; and between superstructure and soil. The increase in bending moment even for a void span of 1/12 of the foundation beam length can become so significant as to exceed the safety provisions. The study shows that the effect of a void on the superstructure moments can be greatly minimized by a combination of rigid foundation and flexible superstructure.


ASCE Subject Headings:
Foundations
Soil-structure interactions
Stiffness
Superstructures
Voids