• Breaking Change
  
• AASHTO LRFD Bridge Design
  
• Moment-Curvature
  
• Eurocodes Accidental Situation for Interaction Surface
  

---

Breaking Change

The Structural Bridge Design Automation solution SBDAutomationLibrary, a sample solution installed with the software that provides access to the design section and beam parameters, has been revised to migrate from using the Newtonsoft.Json package to System.Text.Json. Newtonsoft.Json was a popular choice before the introduction of System.Text.Json, but it's no longer the recommended approach for new development. Any user solutions utilizing these automation library classes may require code changes. The two example projects in the solution have been updated accordingly.

Many properties are no longer initialized in the base classes.

• SBDDesignSection library change example (2025 on the left and 2026 on the right)
  

• Resulting code change to Example 2

---

AASHTO LRFD Bridge Design

Automation of Structural Bridge Design now supports the American AASHTO LRFD Bridge Design Specifications. The key components supported by this automation are:

• Design Sections
• Steel Composite Design Beams
• Pretensioned Prestressed Design Beams.

Refer to the documentation here for more information on automation of Structural Bridge Design.

---

Moment-Curvature

Automation of Design Section analysis now includes Moment-Curvature.

Here is an example of the command needed to run this type of analysis:

"process" : {
  "bridgeName" : "My bridge",
  "commands" : {
    "commandArray" : [
      {
        "commandType" : "SECTION_ANA_MOM_CURVE",
        "commandID" : "C1",
        "wantReport" : true,
        "analysisDetails" : {
          "sectionRef" : "SS1",
          "axial": 125.5,
          "momentType": "MY",
          "curvePoints": 12,
          "wantCurve" : true,
          "includeUnits" : false
        }
      }
    ]
  }

Other optional analysisDetails parameters:

"ratio": "1.2",
"neutralAxisType": "DEFINED",
"neutralAxisAngle": 5.25,
"isAccidental": true

These parameters are documented in the Automation Schema, and also in the SBDAutomationLibrary sample project:

SBDControl.cs
public class AnalysisDetails

---

Eurocodes Accidental Situation for Interaction Surface

The Eurocodes ULS Accidental situation option has been added to interaction surfaces.

For automation, to Eurocodes for commandType of SECTION_ANA_SURFACE, there is now a need to add the boolean property isAccidental to
#/properties/control/properties/process/properties/commands/properties/commandArray/items/properties/analysisDetails.
If omitted, the ULS persistent/transient design situation will be assumed.

---