Secant pile example with DeepXcav
A secant pile wall example will be analyzed with DeepXcav. The following data is available:
a) Soil properties: Sand, friction angle = 30 degrees, total unit weight 120 pcf, loading modulus of elasticity Eload= 300 ksf, reloading modulus of elasticity Eur = 900 ksf. Ultimate bond resistance for ground anchors 40 psi.
b) Excavation depth: 25 ft, cantilever stage 10ft, ground anchor at 8ft depth at 15 degrees. Reinforced piles spaced at 6ft off center, while pile diameter is 2.5ft. Include 600 psf traffic surcharge 1ft behind the wall for a length of 20ft.
Objective: Design the secant pile and the ground achors with allowable stress methodology and obtain a wall embedment safety factor of 1.5. Use reinforced concrete and steel rebars.
By double clicking on the wall and selecting edit properties we can change the wall type and other wall properties as shown in the following figure.
Initial wall properties, with 8 bars #9, piles are spaced at 4 ft O.C.
Next we set the design code standards to US allowable (AISC ASD, and ACI with safety factor)
We then apply 50% wall friction as shown in the next figure:
Ground anchor data Surcharge data
We add a ground anchor and change the properties as shown above. A surface surcarge is also drawn and the vertical magnitude qZ is changed to 0.6 ksf.
Then we perform the analysis by selecting the calculation button. When the analysis is completed the summary tables appear (foollowing image contains snapshots).
Here, we can see that the minimum obtained embedment safety factor is above 1.5. Since it is desired to have a smaller safety factor and realize savings on the wall length, we manually reduce the wall length to 42ft. We then re-analyze the model, and the obtained minimum wall embedment safety factor reduces to 1.532 which is deemed adequate.
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