Soil, Foundation, and Superstructure Interaction (II): Superstructure and Foundations’ Tie Beams Analyses: Fid-Bau Portal

Soil, Foundation, and Superstructure Interaction (II): Superstructure and Foundations’ Tie Beams Analyses

Farouk, Hany / Farouk, Mohamed

The first of these companion papers shows the effect of footing rigidities on the distribution of contact stresses under footings and presents the effect of footing rigidities on increasing maximum flexural moments under footings to be more than that calculated using uniform contact stress. The assumption of uniform contact stresses is widely used in Egypt and overseas when analyzing foundations. Since early implementations, footings were designed and did not collapse due to this problem. Therefore, a study of the factors that are not considered in foundation analyses is required. In this paper, the effects of superstructure rigidity and a foundation’s tie beams, or “semmels”, on the design of foundations are investigated. The superstructure rigidity has significant effects on the redistribution of column loads and the damping of the differential settlements between columns. Superstructure rigidity also affects the values of the modulus of subgrade reactions, which are presented by the geotechnical engineer without considering superstructure rigidity. Therefore, cooperation between the structural and geotechnical engineers is essential to obtain the appropriate straining actions on the superstructure and foundation members. The semmels affect the shape of the contact stress under footings and change the static system of footings. Semmels have minor effects on differential settlement damping, which is not commonly known. The superstructure rigidity also affects the strap foundations, and has a major effect on the redistribution of inner and outer column loads. The strap beam prevents the overturning of outer footings and makes the contact stress under outer footings near uniform.