By: Javier Encinas, PE | July 4, 2018

ASDIP RETAIN is a structural engineering software for the design of retaining walls. It includes the design of cantilever retaining walls supported on piles based on the IBC / ACI 318 provisions. This document is a step-by-step design example of a typical retaining wall on piles using ASDIP RETAIN.

As an example, consider the retaining wall shown below, which is part of an access ramp in a parking garage building. Due to the poor soil conditions, the soils report has recommended the use of steel piles HP12x53, with the shown maximum allowable loads. Design the wall.

Design Steps

1.- Enter the geometric dimensions of the wall. In this case, the stem height is 11'-0". Let's try a stem thickness of 12". Since the wall will be supported on piles, let's specify a footing thickness of 30". The minimum spacing between piles should be 3 pile diameters, so the footing length should be about 6 ft long, leaving 1'-6" edge distance each side. The At-a-Glance tab shows a summary of the design for a quick overview of your work as you go.

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2.- Enter the loads on the wall. The backfill will be a select material with density = 120 pcf and internal friction angle = 30 deg. Enter the surcharge and the concentrated loads given as part of the problem. The Condensed tab shows a more complete set of results grouped by topic, great for a more detailed overview of your design.

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3.- Enter the material properties, which include the allowable capacity of the piles in compression, tension, and lateral, as given in the soils report. The Detailed tab shows a complete set of calculations with exposed formulas and with references to the ACI code.

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4.- Enter the rebars in the stem. The vertical rebars can be cut-off at a certain height to optimize the reinforcement. The Stability tab shows graphically the pressures and forces on the wall, as well as the pile reactions per load combination, and the pile capacity ratios.

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5.- Enter the reinforcement information for the footing. The Graph | Footing tab shows graphically the pile cap in plan and elevation views, with the factored loads and the shear and moment diagrams per load combination.

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Takeaway

ASDIP RETAIN includes the design of retaining walls supported on piles, with multiple options to optimize the design easily. This real-life example shows that the design can be completed and optimized within minutes.