ConcreteBucklingCalculator was added

StructureHelperLogics/NdmCalculations/Buckling/CriticalForceSP63Logic.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperLogics.NdmCalculations.Buckling
+{
+    internal class CriticalForceSP63Logic : ICriticalBucklingForceLogic
+    {
+        double concreteFactor, reinforcementFactor;
+
+        public double GetCriticalForce()
+        {
+            throw new NotImplementedException();
+        }
+
+        public double GetEtaFactor()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}