Tapered Pile with PyPile

Compared to uniform piles, tapered pile has a varied pile width and varied bending stiffness along the pile length. Since usually the angle of tapering is relatively small, the lateral soil resistance affected by the pile width variation is relatively small. To analyze tapered pile under lateral load with PyPile 0.8.5, one can simply changes the pile bending stiffness along the pile length through User Defined Function bending stiffness type.

The User Defined Function uses embedded JavaScript to define the pile bending stiffness at any location below the pile top. The following code shows an example for a tapered pile with a tapering angle of 1 degree, a top diameter of 610 mm, and an elastic modulus of 24 GPa.

function moment(len2top, curvature) {
	var E = 24.0 // GPa
	var D_top = 0.610 // m
	var tapering_angle = 1.0 // degree
	var radius = D_top * 0.5 - len2top * Math.tan(tapering_angle / 180.0 * Math.PI)
	var m = Math.PI / 4.0 * Math.pow(radius, 4) * E * 1e6 * curvature
	return m