CrackWidthCalculator has been added

StructureHelperCommon/Infrastructures/Enums/SectionStressStates.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Infrastructures.Enums
+{
+    public enum SectionStressStates
+    {
+        Tension,
+        Compressed,
+        Combined
+    }
+}