topic Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads in Robot Structural Analysis Forum

Unusual Deformation pattern on top portion of Shaft due to uniform lateral loadings

ADPI — Wed, 08 Jun 2022 12:26:22 GMT

In shaft, Elastic supports are defined in panel thickness definitions. In addition high nodal vertical stiffness is provided at bottom of the shaft. All Local Z axis of panels are directed towards outer face of panels. When uniform effective pressure applied from outside, the deformation of shaft moving outwards at top portions as attached in picture below. How to avoid such deformations or correct the model. (model is attached)

Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

ADPI — Wed, 08 Jun 2022 11:10:17 GMT

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

Simau — Wed, 08 Jun 2022 20:40:44 GMT

@ADPI

Are you sure about the earth pressure?

It should be triangular (like below) with a maximum pressure about 130 kPa at the bottom level

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

Simau — Wed, 08 Jun 2022 21:17:23 GMT

max SLS deformation 5 mm

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

Simau — Wed, 08 Jun 2022 23:01:32 GMT

@ADPI

Sorry, forgot to change surcharge load sign.

Modifications made to the model:

- Z local axis pointing toward the cylinder center

- Uz + uplift for all Thickness

- Earth density 18 kN/m² and k=0.33

Max SLS deformation is now 28 mm

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

ADPI — Thu, 09 Jun 2022 03:21:12 GMT

yes.. Earth pressure values are given by Plaxis inputs and agreed with Geotech team. They vary along the height of shaft.

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

ADPI — Thu, 09 Jun 2022 03:16:46 GMT

yes. I Agree with deformation values. But this deformation value should be in opposite direction where big opening is present. Since all lateral loads are pushing shaft towards its center, displacement at top portion should be lean towards center of shaft. But in this case, displacement is moving outwards, which is not practical as per load application.

Re: Unsual Deformation at top edge of Shaft in case of Uniform lateral loads

Simau — Thu, 09 Jun 2022 11:48:40 GMT

@ADPI

The model modified attached for your use