Reinforced Concrete Tilt-up, Precast, ICF Wall Analysis & Design Software

From shear walls and retaining walls to precast, ICF, and tilt-up walls, engineers worldwide use spWall v5.01 to optimize complicated wall design, reinforcing, and deflections.

spWall, formerly pcaWall/PCA-Tilt/TILT, is a program for design and analysis of cast-in-place reinforced concrete walls, deep beams, coupling beams, tilt-up walls, ICF walls, and precast architectural and load-bearing panels.

Upgraded to ACI 318-14 and CSA A23.3-14, spWall's graphical interface easily generates complex wall models. Wall geometry (including any number of openings and stiffeners), material properties, loads (point, line, and area), and the support conditions are assigned graphically by the user. Also, springs (translational and rotational) can be graphically assigned at any node.

spWall uses a finite element solver and takes into account second-order effects. The wall may include any number of openings and stiffeners. The amount of steel required for flexure is computed based on the selected design standard, and the user can specify one or two layers of reinforcement.

The program calculates the required amount of reinforcement in the plate elements and stiffener elements based on the code selected by the user. For solid walls, spWall can also compare cross-sectional shear forces with calculated in-plane and out-of plane shear strength provided by concrete.

spColumn complements spWall by generating axial/flexure (P-M) diagrams suitable for shear wall design.

User Interface

Tilt-up Walls

Shear Walls

Solid wall with thickened ends

with openings and coupling beams

Retaining Walls

Stem of a Retaining Wall with Pilasters

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Finite element Method

spWall uses the Finite Element Method for the structural modeling and analysis of slender and non-slender reinforced concrete walls subject to static loading conditions. The wall is idealized as a mesh of rectangular plate elements and straight line stiffener elements. Six degrees of freedom exist at each node: three translations (Dx, Dy, Dz) and three rotations (Rx, Ry, Rz) relating to the three Cartesian axes. The bending behavior follows the thin plate theory (Kirchhoff theory).

Finite Element Meshing – Node and Element Numbering

Reinforcement Design

For each plate element, the required areas of horizontal and vertical reinforcement are computed based on the average moments per element and are output along with design forces and governing ultimate load combination. In both horizontal and vertical directions, the reported reinforcement is the total required area of steel per unit length. Half of the reported value applies to each curtain in models with two curtain layout.

For each stiffener element, the required area of longitudinal reinforcement for flexure and axial loads, transverse reinforcement required for shear and torsion, and longitudinal torsional reinforcement are output along with the design forces and governing ultimate load combination.

Plate Element

Stiffener Element

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Wall Contours

Plate Reinforcement

spWall allows specifying one or two layers of reinforcement and reports the total required reinforcement quantities per unit length in both graphical and text results form. The half of the reported value applies to each layer in models with two layer reinforcement layout. The base reinforcement ratio can be specified by the user that is taken into account (base reinforcement shown with blue color in contour views below) by the Program when displaying reinforcement contours.

Shear Wall Model Design Reinforcement (Asy) Vertical

Required Total Reinforcement Along X-Direction (in²/ft)

Required Total Reinforcement Along Y-Direction (in²/ft)

Reinforcement Contour Views – Envelope Values – 4-story Shear Wall

Displacement

spWall reports displacements, both out-of-plane and in-plane, for individual service and ultimate load combinations as well as envelope values. The user may set a user-defined permissible out-of-plane deflection or utilize default H/150 limit.

Displacements (Out-of-Plane), in.

Envelope Service Displacements Out of Plane

Displacements (In-Plane), in.

Service Displacements Contour View – Envelope Values – 4-story Tilt-up Wall with openings

Force Diagrams

Wall Cross-sectional Forces

Diagrams of wall cross-sectional forces (Nuy, Vux, and Vuz) and moments (Mux, Muy, and Muz) at horizontal sections along the wall height are displayed.

Axial Force Diagram– Nuy (kips)

Shear Model Wall cross sectional forces Vux

Shear Force Diagram – Vux (kips)

Shear Wall Model Wall cross sectional forces Muz

Moment Diagram – Muz (ft-kips)

Force Diagrams - Wall cross-sectional forces due to in-plane loading

Tilt up Wall Model Wall cross sectional forces Nuy

Axial Force Diagram– Nuy (kips)

Tilt upWall Model Wall cross sectional forces Vuz

Shear Force Diagram – Vuz (kips)

Tilt upWall Model Wall cross sectional forces Mux

Moment Diagram – Mux (ft-kips)

Force Diagrams - Wall cross-sectional forces due to out-of-plane loading

Stiffener Elements

spWalls allows the use of stiffener elements to model beams or columns that are either embedded in the wall, e.g. lintels, pilasters, and boundary elements of shear walls or as isolated elements placed outside of the wall to model rigid frame structures attached to the wall.

36”x24” Pilasters with 24”x36” DP Lintels

Wall with Stiffeners Stiffener internal forces Nx

Stiffener Axial Force, Nx Diagram (kips)

Wall with Stiffeners Stiffener internal forces Vy

Stiffener Shear Force, Vy Diagram (kips)

Wall with Stiffeners Stiffener internal forces Mz

Stiffener Moment, Mz, Diagram (ft-kips)

Force Diagrams – Stiffener Internal Forces

4-Story Wall with openings under Earthquake loading – Modeled with Stiffeners as Pilasters and Lintel Beams

Wall Shear Strength provided by Concrete

In spWall, the wall shear strength provided by concrete (in-plane and out-of-plane) is calculated allowing the user to determine the need for adding shear capacity.

In-plane Shear, Φ Vcx (kips)

Wall Shear Strength Provided by Concrete Out of Plane

Out-of-plane Shear, Φ Vcz (kips)

Force Diagrams - Wall Shear Strength provided by Concrete

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Second Order Analysis

spWall can perform second-order analysis in which the effect of in-plane forces are taken into account on the out-of-plane deflections. If second order analysis is requested (the default setting), a complete analysis cycle is done for each load combination. In each cycle, the basic stiffness terms of plate elements are modified to account for the effect of membrane forces. For stiffener elements, the basic stiffness matrix is modified to account for the effect of axial forces.

Reactions

spWall reports the restraint and nodal spring reactions for individual service load and ultimate load combinations. Nodal translational reactions Fx, Fy, and Fz, and rotational reactions Mx, My, and Mz are output. The program also reports sum of forces and moments (with respect to wall center of gravity) for applied loads and reactions.

Reactions at the Base – Ultimate Load Combination – U6

Stiffener Element

Stiffener elements can be used to model beams or columns that are embedded in the wall to increase its structural capacity, e.g. lintels, pilasters, and boundary elements of shear walls. Wall piers that are required to be designed as columns can also be modeled using stiffeners. Additionally, isolated stiffener elements placed outside of the wall can model rigid frame structures attached to the wall. The program will calculate internal forces in the stiffener elements and calculate the area of reinforcement required for axial action combined with biaxial bending as well as shear and torsion.

Stiffener Design Criteria – Reinforcement Layout