Vertical Bearing Capacity - Spring Method
The "Vertical bearing capacity" frame allows for verifying the pile vertical bearing capacity. The analysis is performed automatically when switching to this frame. More computations can be performed in the frame. The verification can be performed for individual loads, or the program finds the most critical one (can be selected from a combo list).
The analysis is performed with the help of spring method. The results are automatically updated whenever one of the analysis parameters "Maximal deformation", "Coefficient increasing limit skin friction due to technology" or "Procedure determining influence zone" is changed.
Two options are available to determine influence zone:
- By default, the evaluation of the depth of influence zone below the pile base follows the procedure described in the theoretical part of the help in section "Depth of influence zone". The depth of influence zone on the pile skin is determined as a k-multiple of the pile diameter. The value of k increases from 1 for zero load to the value of 2.5 when exceeding the limit skin friction.
- The second option assumes the depth of influence zone below the foot and on the skin to be set conservatively a kth multiple of the pile diameter, where the value of k can be selected. During a gradual increase of pile surcharge the value of k for the depth of influence zone on the pile skin is continuously changed from 1 at the onset of load to the specified value when exceeding the limit skin friction. The value of k for the influence zone below the pile base remains constant during the analysis.
The second method, originally used in the old version GEO4, with the value of k = 2.5 offers less accurate results and usually underestimates the pile bearing capacity. Therefore a new option that allows for specifying the depth of influence zone through analysis is offered and is also recommended by the default setting.
Switching between results is available in the left part of the frame (load-settlement curve, distributions of internal forces, dependence of shear on displacement). The shear-displacement relationship is derived for a given depth measured from the pile head. The results are updated whenever the depth is changed.
The "In detail" button opens the dialog window, which contains a detailed listing of the results of verification analysis.
Visualization of results can be adjusted in the frame "Drawing Settings".
Frame "Vertical bearing capacity" - analysis using spring method