5. Cantilever Retaining Wall Foundation Analysis and Design - spMats Software

spMats uses the Finite Element Method for the structural modeling, analysis, and design of reinforced concrete slab systems or mat foundations subject to static loading conditions.

The slab, mat, or footing is idealized as a mesh of rectangular elements interconnected at the corner nodes. The same mesh applies to the underlying soil with the soil stiffness concentrated at the nodes. Slabs of irregular geometry can be idealized to conform to geometry with rectangular boundaries. Even though slab and soil properties can vary between elements, they are assumed uniform within each element. Piles and/or supporting soil are modeled as springs connected to the nodes of the finite element model.

For illustration purposes, the following figures provide a sample of the input modules and results obtained from an spMats model created for the cantilever retaining wall foundation in this design example.

5.1. Cantilever Retaining Wall Foundation Model Input

Figure 17 - spMats Interface

Figure 18 - Assigning Soil Lateral Moment for Cantilever Retaining Wall Foundation (spMats)

Figure 19 - Assigning Soil Toe Load for Cantilever Retaining Wall Foundation (spMats)

Figure 20 - Assigning Soil Heel Load for Cantilever Retaining Wall Foundation (spMats)

Figure 21 - Assigning Surcharge Load for Cantilever Retaining Wall Foundation (spMats)

Figure 22 - Assigning Wall Load for Cantilever Retaining Wall Foundation (spMats)

Figure 23 - Solve and Mesh Options (spMats)

5.2. Cantilever Retaining Wall Foundation Results Contours

Figure 24 - Vertical (Down) Displacement Contour (spMats)

Figure 25 - Vertical (Up) Displacement Contour (spMats)

(Note: figure indicates no uplift in the wall base)

Figure 26 - Soil Bearing Pressure Contour for Case 1 (spMats)

Figure 27 - Soil Bearing Pressure Contour for Case 2 (spMats)

Figure 28 - Moment Contour along X-Axis (Max for Toe) (spMats)

Figure 29 - Moment Contour along X-Axis (Max for Heel) (spMats)

5.3. Cantilever Retaining Wall Foundation Required Reinforcement

Figure 30 - Required Reinforcement Contour along X Direction (Bottom - Toe Design) (spMats)

(Note: minimum reinforcement governs)

Figure 31 - Required Reinforcement Contour along X Direction (Top - Heel Design) (spMats)

(Note: minimum reinforcement governs)

5.4. Soil Reactions / Pressure

Figure 32 - Soil Service Reactions

Figure 33 - Soil Bearing Pressure

5.5. Cantilever Retaining Wall Foundation Mesh Status

Since spMats is utilizing finite element analysis to model and design the foundation. It is useful to track the number of elements used in the model to optimize the model results (accuracy) and running time (processing stage). spMats provides mesh status to keep tracking the mesh sizing as a function of the number of elements, minimum and maximum element sizes, and maximum aspect ratio.

Figure 34 - Mesh Status