ASDIP CONCRETE is a structural engineering software for design of concrete members. It includes the design of biaxial slender columns based on the latest ACI 318 provisions. But how do you actually enter the information in the program? How do you check the results? How do you optimize the design? How do you print out the reports? Following is an overview of the user-interface and the steps required to design concrete columns using ASDIP CONCRETE.
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Specify the column geometry
ASDIP CONCRETE supports two types of columns according to the shape of the cross section. In the Geometry tab select the column type, either Rectangular or Circular. Enter the dimensions of the section and the reinforcing bars. Note that in ASDIP CONCRETE the rebars are specified as Top/Bottom and Left/Right bars, as shown below for rectangular columns. For circular columns enter the number and size of longitudinal bars and the software will distribute the reinforcement evenly around the column.
Enter the member length and effective length factors in both directions. In addition specify whether the column is sway or non-sway for lateral stability. This information is important to determine the slenderness effects in the column.
The software generates the interaction diagram of the column, which represents the design capacity for a combination of axial load and bending moment.
ASDIP CONCRETE shows a summary of the results in the At-a-Glance tab for a quick overview of the concrete column design as you go. The screen shot below shows the Geometry tab and the At-a-Glance tab. Note that in this page any problem can be identified immediately.
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Specify the material properties
In the Materials tab enter the material properties. ASDIP CONCRETE lets you specify the concrete stress-strain distribution as either the parabolic Hognestad's curve, or the simplified equivalent Whitney's rectangular block.
Likewise, ASDIP CONCRETE lets you specify the steel stress-strain distribution as either the Elasto-plastic bi-linear relationship, or considering the Strain-hardening zone.
Note that the results update instantly after each change in the input data. This allows to do a "what-if" analysis with no effort. This way the design of concrete columns can be optimized easily.
ASDIP CONCRETE generates a condensed presentation of the results, with a more detailed information organized by topic and load combination, for a quick granular check of the column design as you go. The screen shot below shows the Materials tab and the Condensed tab.
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Enter the applied loads
Use the Loads tab to enter the applied loads on the column. ASDIP CONCRETE lets you specify axial loads and bending moments at top and bottom. Loads can be specified either a set of load cases, such as dead, live, roof live, snow, wind, and seismic, to be combined per the specified load combinations, or a set of pre-combined loads. For the latter loads, it's assumed that they were combined somewhere else, and therefore no further load factors are applied. This is useful when you need to use the output loads from another software.
If the Biaxial Column check box is checked, the user interface of ASDIP CONCRETE changes to allow biaxial moments, and it generates a 3D interaction diagram in the Graph tab.
ASDIP CONCRETE generates a detailed presentation of the results, showing step-by-step calculations organized by topic and load combination, with exposed formulas and references to the ACI code. This is excellent for a deep granular check of the design. The screen shot below shows the Loads tab and the Detailed tab.
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Consider the second order effects
The second order moments due to the slenderness effects are considered in two ways: first, if the applied loads come from a second order analysis, no further load modification is required. Second, if the loads come from a first order analysis, then a magnification of the moments is necessary. ASDIP CONCRETE performs this step per the ACI Moment Magnification Method, as shown below.
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ASDIP CONCRETE generates an image of the interaction diagram in 2D and 3D, as shown below. This graphical view can be used to double check the specified rebar sizes, and also check that the points that represent the factored loads fall inside the usable area.
ASDIP CONCRETE includes the design of biaxial slender columns. The graphical user interface is simple and intuitive, with multiple options to optimize the design easily. The results are shown instantly in both text and graphics format.
For engineering background, please read the blog post
Concrete Column Design – Structural Overview. For a design example, please see the blog post Biaxial Column Design Example Using ASDIP CONCRETE. For our collection of blog posts about concrete design please visit Structural Concrete Design.
Javier Encinas, PE
ASDIP Structural Software