Product(s):	RAM Connection
	Version(s):	Any
	Environment:	N/A
	Area:	Design
	Original Author:	Bentley Technical Support Group

Problem Description

After assigning a base plate connection, the Results Report indicates that a solution was not found for one or more load conditions. See below:

Reason

The program cannot find an equilibrium solution using the assumptions for concrete compressive stress and anchor tension. Typically, these errors occur when large moments or uplift forces transferred to the base plate.

Solution

1.  Exclude the load cases, so that the base plate is designed using load combination forces only. See the frequently asked question, "Why is the controlling load condition reported as a single load case?" here for details: RAM Connection Capabilities and Modeling FAQ

2.  Edit the connection and check the box for "Consider Strain Compatibility" (see below). When strain compatibility is not considered, the analysis assumes that the maximum concrete compressive stress equals the code allowable concrete bearing capacity and then calculates the anchor forces to achieve force equilibrium. When strain compatibility is considered, the analysis assumes that the base plate is fully rigid and the compression and tension strains are calculated assuming a lineal relationship. More information on this option can be found here: Biaxial Analysis of General Shaped Base Plates

3.  If Steps 1 and 2 do not prevent the errors from occurring, edit the connection and change the Pressure Distribution from "Uniform" to "Triangular" (see below). "Uniform" assumes a uniform bearing stress on the base plate and follows from AISC Design Guide 1. "Triangular" assumes a triangular pressure distribution on the base plate and follows the alternate procedure discussed in Appendix B of AISC Design Guide 1.