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I posted the query because I recently read two articles: one is FOUNDATIONS FOR SHEAR WALL STRUCTURES by J.R. Binney and T Paulay, and the other one FOUNDATIONS FOR CAPACITY DESIGNED S T R U C T U R E S by P.W. Taylor and R.L. Williams. @Rana : This is not enough. These details ensure the development of column hinge at the bottom if it is possible. And that "if" depends on the soil-structure interaction and the strength of the soil. If the soil is strong enough to resist bearing pressure corresponding to forces (axial load + moment) that it may experience when the column will be in inelastic range (capacity design approach), and if you have designed the footing for the moment that it may experience when hinge (capacity design approach) will form in the column, which is, of course, greater than the moment that you will get from ETABS for the design Earthquake, then the hinge will form in the column. If the above scenario is not feasible then you may proportion the footing to allow the rocking behavior so that energy may be dissipated provided footing rotation is in permissible limits, which will depend on the soil-rotation relationship. @umer: In MAT, or other connected foundation types, the third option is to allow nonlinear behavior in the foundation. In that case, the foundation should be detailed for attaining necessary ductility levels. These things are not discussed in the ACI code. I have not read these things in RCC books as well.

what else is required in conventional codal design other than proper detailing and developing bars for ductility? I found this useful; https://www.housingauthority.gov.hk/tc/common/pdf/business-partnerships/resources/concrete.pdf

1-as we have To follow simplified approach in structural software to model geotechnical properties,as you are right that modulus of different soil will be different therefore i have uesd a word" accordingly". 2-anyway there are many other ways to incorporate the lateral stiffness/vertical stiffness approxiamately,Thanks .

Does anyone practice the design philosophy that ensures the formation of plastic hinges at the bottom of the column, near the foundation, for isolated footing?

Thanks Umar this will help (y)

Thanks for the great reply. I will just add that modulus of different soil layers is different so the pile to be divided either equally within each layer. Thanks

1-Horizental (lateral stiffness) or vertical spring constant?and it will be better that you you go for point spring in case of pile rather then line spring. 2-multiply the modulus of subgrade reaction with area of pile. 3-divide the pile length into equal parts(to add modulus of subgrade reaction accordingly) and, assign the joint at intervals and then apply joint spring. 4-you will get approximately not exactly bending moments/shear force depending upon the pile end condition fixity or partially fixed ,free whatever you have.

IMO, you must check & verify your design through manual calculations. Following links provide procedure and examples, for designing of strap footings manually: 1. Strap Footing- Shallow Foundations.pdf 2. Special Footings and Beams on Elastic Foundations.pdf 3. Strap Footing Design.pdf Regards.