User data for cracks were added

StructureHelperLogics/NdmCalculations/Cracking/SofteningLogics/ICrackSofteningLogic.cs

@@ -0,0 +1,21 @@
+using StructureHelperCommon.Infrastructures.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperLogics.NdmCalculations.Cracking
+{
+    /// <summary>
+    /// Logic of calculating of factor of softening in crack of RC structures
+    /// </summary>
+    public interface ICrackSofteningLogic : ILogic
+    {
+        /// <summary>
+        /// Returns softening factor
+        /// </summary>
+        /// <returns></returns>
+        double GetSofteningFactor();
+    }
+}