Steel Structural Design: Beams, Columns, Base Plates, Lugs, Connections

Base plates are elements required at the end of columns to distribute the concentrated load of the column over a much larger area of the material that supports it. The design of column base plates involves two main considerations: One, spread the load so as to maintain the bearing pressures under the allowable values, and the second is with the connection, or anchorage, of the base plate and column to the concrete foundation.

The software performs the column steel base plate design resting on a concrete support and subjected to any combination of axial load and biaxial bending moments, including uplift loading. In addition, this program computes and checks the maximum bearing stress on the support, as well as the tension and shear forces per anchor rod. The column may be eccentrically placed on the concrete support.

For base plates with moments, the strain compatibility is enforced. ASDIP STEEL performs the anchor bolts design per the latest provisions of the ACI 318-19 Chapter 17 “Anchoring to Concrete”, and it includes checks for all failure modes in both tension and shear, interaction effects, and reinforcing design. Shear lugs can be designed as well. The software considers the ACI and AISC seismic provisions. Load combinations per ASCE 7-05 or 10/16 or user-defined.

Input

The input options are conveniently organized in tabbed pages. The input data required includes the plate, column and pier dimensions, the edge distance from anchor rods, the materials properties and the acting loads, either per ASD or LRFD. Loads cases can be specified to be combined internally, or a set of pre-combined loads can be entered as well. Select the column properties and the anchor rod material from the built-in databases.

Output

ASDIP STEEL structural design software calculates the bearing pressure under the plate and finds the required plate thickness. In addition, it check the bearing capacity of the support. The anchor rods are checked for all failure modes in tension and shear, and the interaction of both. Shear lugs limit states are also checked when specified to resist the shear load.

A detailed step-by-step report is available to the touch of a tab, which is updated with every new change. In addition, ASDIP STEEL uses a pre-formatted colorful text-with-values output for easier identification of the problem areas. ASDIP STEEL generates a graphical view of the designed base plate and the resulting bearing pressures and anchor rod forces, as well as the breakout areas in tension and shear.

Columns are structural members that mostly work in compression and bending. Often buckling, or sudden bending as a result of instability, occurs prior to developing the full material strength.

This steel structural design software performs the steel column design, either sway or non-sway, subjected to axial load an biaxial moments, based on the AISC ASD or LRFD methodology. It checks the axial, bending and combined stresses according to the AISC 360-16 specifications (15th Ed. Manual). Load combinations per ASCE 7-05 or 10/16. The design may either include or ignore the AISC seismic provisions.

Depending whether the source of the loads is a first or a second order analysis, two procedures may be followed:

• Second Order Analysis – It considers the P-Delta and P-delta effects. No further amplification is required.
• Amplified First Order Analysis – In this case the software will calculate the amplified moments per the AISC Moment Magnification Method.

Input

The required input data consists of steel yield strength, member length, and unbraced length. In addition, the effective length K-factors in both directions are required. Either service or factored loads may be specified. Load cases are internally combined, or you may enter a set of pre-combined loads. The software includes the AISC Seismic Provisions.

Output

ASDIP STEEL structural design software calculates the maximum slenderness ratio and the compressive strength. Based on the section properties the software calculates the bending strength in both directions. Finally it checks the combined stress ratio.

Use the Design Manager to find all the steel sections that meet this design criteria. Sort the table if you wish, either by weight or by design ratio. Finally, when you select one of these winner sections, the corresponding properties are transferred automatically to your calculations.

For a quick check of the overall design, click on the “At a Glance” tab. For a more detailed set of step-by-step design calculations click on the “Condensed” or “Detailed” tabs.