FAQs

What is the difference between spColumn and pcaColumn?

pcaColumn, also formerly known as PCACOL and IRRCOL, was renamed spColumn to better relate and support the registered trade name of the publisher, StructurePoint, formerly the PCA's Engineering Software Group.

Which design codes does spColumn support?

spColumn supports latest American (ACI 318-19) and Canadian (CSA A23.3-19) design codes. For complete list of supported design codes please visit spColumn features and advanced features.

What kind of sections can spColumn handle?

spColumn can design and investigate regular (rectangular, circular) sections with predefined reinforcement patterns (all sides equal, equal spacing, and sides different). The Program can also investigate irregular sections with irregular reinforcement patterns using sophisticated section editor built with easy and simple user interface.

More information about this topic can be found in Section 4.1.3 of spColumn Manual.

How does spColumn handle irregular sections?

spColumn can investigate any irregular sections (solid or hollow) with reinforcement size and locations specified by user. Only Investigation option is provided for irregular sections. Irregular shapes and reinforcement patterns can be easily modeled using design assistant, templates, section editor and DXF import options provided in spColumn. Irregular sections may be modeled with multiple solids with multiple openings in them. This is useful for building core walls, elevator shafts, and unique bridge piers

I've downloaded spColumn, but how I can get the manual?

spColumn Manual can be accesses in one of the three ways: From the program help menu; from the spColumn installation folder; or from this web link.

Can I import the loads obtained from third-party structural analysis programs into spColumn?

Yes. Service or factored loads from third-party structural analysis programs can be imported into spColumn in a text file format. See Appendix section of spColumn Manual for more information on file format. Also load data from ETABS can be imported allowing faster interoperability and design iterations. See Section 5.6.4 of spColumn Manual

What is the method of solution of spColumn for biaxial bending of concrete columns, e.g. PCA Load Contour method or Exact Integration method?

spColumn utilizes neither PCA Load Contour Method nor Exact Integration Method for biaxial runs. Instead, predetermined values of axial loads are calculated and for each level of axial loads, spColumn rotates the section in 10-degree increments (there will be a total of 36 rotations for a 360 degree run) and the values of Mx and My moment capacities are calculated and thus an Mx-My contour is developed. Repeating this for the entire range of axial loads, the three-dimensional failure surface is created.

The comparison between the approximate procedures and spColumn procedure is discussed in details in "Manual Design Procedure for Columns with Biaxial Bending" design example.

What is a CTI file?

CTI file is the Text Input format for spColumn. This file contains all the information that spColumn needs to run and produce results. It can be created easily using spColumn by defining a simple section with basic reinforcing and then save the file as a CTI file (extension). This will save the format which can then be used as a template for any future CTI files.

More information about this topic can be found in Appendix A.3 in spColumn Manual.

How is CTI file used?

CTI files are generally used by the batch mode. spColumn user manual has a detailed section designed to help users modify and develop their CTI files for detailed section designed to help users modify and develop their CTI files for batch mode analysis. Many users devised in-house scripts to further leverage this feature and connect with other software tools and BIM programs.

More information about this topic can be found in Appendix A.3 in spColumn Manual.

What is Batch Mode run in spColumn?

The batch mode feature of the program is a great automation tool to streamline the column design/investigation process. Intended for integration with 2D/3D structural analytical models, the batch mode enables the execution of hundreds of column text input files that include all of the column properties and loading conditions in a single click and produces results like interaction diagrams, interaction diagram data, column section dxf files, and all graphical results.

More information about this topic can be found in Section 6.2 in spColumn Manual.

Can I export the interaction diagram to a Word document?

Yes. Open spColumn report by selecting the Reporter command from the View menu. After opening spColumn report, press "Word" type then click the "Export" button. spColumn report (including interaction diagrams) can be exported in 5 different formats: Word (.docx), PDF (.pdf), Text (.txt), Excel (.xlsx), and CSV (.csv).

Alternatively, open a Word file first, then after the calculation is done select Menu View | Copy Diagram to Clipboard. Go back to Word, select Paste from the Edit menu.

How can I find the values of axial load, P, and moment, M_x (or M_y), of each load points in P-M_x (or P-M_y) interaction diagram?

There are two ways to do this:

You can move the mouse cursor along the P-M interaction diagram, the P and M coordinates of the point where the current mouse point is located are shown in the status bar, as well as the eccentricity. If status bar is hidden, select menu View | Status Bar to make it visible.

Or values of axial and moment capacities together with corresponding neutral axis locations, maximum steel strains, and strength reduction factors (ACI code only) for each calculated point on the interaction diagram or 3D failure surface can be found by exporting current interaction diagram or the whole 3D failure surface to a text file (comma separated or tab-delimited). To do so, select Menu File | Export | Diagrams - To CSV/TXT | Factored Interaction Diagram [File | Export | Diagrams - To CSV/TXT | Nominal Interaction Diagram] or File | Export | Diagrams - To CSV/TXT | Factored 3D Failure Surface [File | Export | Diagrams - To CSV/TXT | Nominal 3D Failure Surface].

Where can I find the neutral axis depth in result report?

For uniaxial runs, neutral axis depth (along with maximum steel strain and strength reduction factor for ACI code) of each point corresponding to calculated capacity will be listed in the table on the bottom of the result report. The same applies to biaxial runs when Control Points are selected as load type.

For other load types in case of biaxial bending, neutral axis location, maximum steel strain, and strength reduction factor (ACI code only) for each calculated point on the 3D failure surface can be found by exporting current interaction diagram or the whole 3D failure surface to a text file (comma separated or tab-delimited).

How can I change the default strength reduction factors used by the program?

Select Define | Properties | Reduction Factors. Select Other in the Confinement drop down list, then the text boxes for ϕ_(a), ϕ_(b), and ϕ_(c) are editable.

I would like to know where in the manual I can find the Moment Signs adopted for single or double curvature at columns.

In the Loads | Service Loads Menu there is a diagram indicating the sign convention. If Moment @ Top and Moment @ Bottom values are entered as same sign, this results in double curvature. If these values are entered as opposite sign, then it results in single curvature. Detailed information on sign conventions can be found in Section 2.1.2 in spColumn Manual.

Can I get the area of reinforcement, or the ratio of "A_s,provided/A_s,required" ?

The program calculates the ratio of the moment capacity to the applied moment, ϕM_n/M_u, at each axial load level which assesses safety of the section similarly to how the ratio of A_s,provided/A_s,required would.

The total area of provided steel, A_s, for the selected bars (design mode) or the input bars (investigation mode) is displayed on the screen and is also reported in the text output. The area of required steel, however, is not a parameter used in spColumn and is not reported.

All of my slenderness menu items are disabled. Why?

In spColumn main screen, select "Yes" for the "Consider slenderness?" under "Run Options" in the "Project" left panel. More information about slenderness can be found in "Slender Concrete Column Design in Sway Frames" design example, "Slenderness Effects for Columns in Non-Sway Frame" design example and Section 5.3.5 in spColumn Manual.

The "Axial Load Points" menu item is disabled. Why?

"Axial Load Points" are not supported when "Biaxial" is selected in the "Project" left panel. Select "About X-Axis" or "About Y-Axis" to enable it.

Where can I enter the cracked-section coefficients?

Select Slenderness | Slenderness Factors. More information about slenderness factors can be found in Section 5.3.5.4 in spColumn Manual.

How can I get the capacity of a column section without any load input?

After the geometry and reinforcement are defined, select Menu Input | Loads | Control Points. In Control Points Mode, the Program calculates the interaction diagram (capacity diagram) and reports several key points on the interaction diagram. More information about control points can be found in Section 4.27 in spColumn Manual.

Which axis does I_x or I_y refer to?

I_x or I_y refers to the x or y axis going through the centroid of the section. It does NOT refer to the x or y axis shown in the section window and section editor.

Can I import sections from AutoCAD to spColumn? Can I export sections from spColumn to AutoCAD?

Yes, you can import sections from any drafting software, such as AutoCad, to spColumn using DXF files. To import DXF files, select File | Import | Section - From DXF.

Also, you can export sections from spColumn to any drafting software, such as AutoCad, using DXF files. To export DXF files, select File | Export| Section - To DXF.

Why am I getting the spColumn error "Section layer is empty. - Add solid shape" when I import a section using DXF file even though the section is defined?

The section should be defined in a layer that contains a closed polyline entity (either LWPOLYLINE or POLYLINE) in the DXF file to be identified by spColumn as a solid section. To solve this issue, convert or redraw the section as a closed polyline entity (either LWPOLYLINE or POLYLINE). More information about importing DXF files can be found in Section 5.6.2 in spColumn Manual.

Why am I getting the spColumn warning "Cannot achieve desired accuracy"?

For members with large cross-sectional area, spColumn sometimes warns the user with the following message "Cannot achieve desired accuracy". This results when the program cannot meet the predefined convergence criteria and the corresponding point on the interaction diagram may be slightly off. The convergence criteria is more stringent than required in engineering practice, however, the shape of the interaction diagram should be verified to be relatively smooth and free of unexpected discontinuity.

For section capacity, what is the difference between "Moment-Capacity Method" and "Critical-Capacity Method"?

Moment-Capacity Method calculates the section capacity as the ratio of moment demand, M_u to moment capacity, ϕM_n. When a unique value of ϕM_n cannot be calculated for a given load point, this method gives the capacity ratio as "> 1" or "< 1" depending on the location of the point.

Critical-Capacity Method calculates the section capacity based on the closest distance to a load-point from the normalized interaction diagram.

More information about section capacity methods can be found in Section 2.4 in spColumn Manual.

What is "Irregular" section editor for?

"Irregular" section editor enables the user to investigate irregularly shaped reinforced concrete sections subject to a combination of loadings. "Irregular" section editor considers a polygonal section reinforced with bars located at any location. The section may contain one or multiple openings.

More information about "Irregular" section editor can be found in Section 4.1.3 in spColumn Manual.

What is "Reporter" module for?

"Reporter" module enables the user to view, customize, print and export reports in different formats.

"Reporter" module is accessed from within spColumn. Once a successful run has been performed, you can open the "Reporter" module by pressing the F7 key or by clicking on the "Reporter" button in the program toolbar. Immediately after opening "Reporter" module, you can export and/or print the default report by pressing Export/Print button. Various options to customize the report before printing and/or exporting it are also provided. Once the work in "Reporter" module is completed, click the close button in the top right corner to exit the "Reporter" window.

More information about "Reporter" module can be found in Section 3.4 in spColumn Manual.

What is "Diagrams" Module for?

"Diagrams" Module enables the user to view and analyze 2D interaction diagrams and contours along with 3D failure surfaces in a multi viewport environment. "Diagrams" Module is accessed from within spColumn. Once a successful run has been performed, you can open the "Diagrams" Module by clicking "Diagrams" button in the program toolbar.

More information about the "Diagrams" Module can be found in Section 7.2 in spColumn Manual.

Why am I getting the spColumn note "Reinforcement ratio is less than 1%. Consider column as Architectural?"? And why does spColumn distinguish between structural columns and architectural columns?

Columns are generally designed with reinforcement ratio between 1% to 8% of the gross section area. Oversized columns, widely referred to as "Architectural Columns", are often needed for functional purposes resulting in reinforcement ratios below 1%. spColumn will recommend to consider columns with reinforcement ratios between 0.5% and 1% as architectural columns where the axial and flexural capacities will be reduced based on the selected code provisions. For ratios below 0.5% and more information about this topic refer to "Columns with Low Reinforcement - Architectural Columns" technical article and Secion 2.2.3 in spColumn Manual.

Why am I getting the spColumn error "Magnified (second-order) moment exceeds 1.4 times first-order moment. Revise design!"

For spColumn calculations in accordance with ACI 318-19/14/11/08, the value of total magnified moment including second-order effects (combined magnification at ends and along length of compression member) cannot exceed 1.4 times the corresponding moment due to first order effects. Columns with second-order moment to first-order moment ratios exceeding 1.4 do not meet requirements of ACI 318-19/14/11/08.

More information about this topic can be found in "Slenderness Effects for Concrete Columns in Sway Frame - Moment Magnification Method" design example and Section 2.3.5 in spColumn Manual.

Does spColumn check AASHTO code provisions?

Load factors, load combinations, and capacity reduction factors for AASHTO LRFD code may be entered into spColumn to run the column section.

To modify capacity reduction setting, the user may change the design code specific default capacity reduction factors used by the program by selecting "Other" in the Confinement drop down list under Define | Properties | Reduction Factors. Once "Other" is selected, then the text boxes for ϕ_(a), ϕ_(b), and ϕ_(c) become editable and values from other codes can be inserted.

AASHTO LRFD standard will be incorporated in an upcoming release.

Does spColumn provide the maximum steel strain for my load point?

For each point on a P-M interaction diagram or on a 3D failure surface, spColumn calculates the location of the neutral axis (expressed in terms of depth and angle of the neutral axis), maximum steel strain, and (for ACI codes only) the strength reduction factor. These results are reported for the maximum capacity of the section based on the ultimate limit states and not for the given loading input. More information about this topic can be found in "Column Section Demand-Capacity Ratio Determination" technical article.
 

How do I use Command Line Interface (CLI) in spColumn

spColumn solver can be run in batch mode from the command line prompt. Command line runs can be done by invoking spColumn.CLI.exe after navigating to the directory in which spColumn is installed. Input data file, output data file, and run options can be passed to the program via parameters. More information about this topic can be found in Section 6.3 of spColumn Manual.