Measurements of units were added

StructureHelperCommon/Infrastructures/Enums/UnitTypes.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Infrastructures.Enums
+{
+    public enum UnitTypes
+    {
+        Length,
+        Area,
+        Stress,
+        Force,
+        Moment
+    }
+}

StructureHelperCommon/Infrastructures/Strings/ErrorString.cs

@@ -15,5 +15,6 @@ namespace StructureHelperCommon.Infrastructures.Strings
         public static string ShapeIsNotCorrect => "#0004: Shape is not valid";
         public static string LimitStatesIsNotValid => "#0005: Type of limite state is not valid";
         public static string LoadTermIsNotValid => "#0006: Load term is not valid";
+        public static string IncorrectValue => "#0007: value is not valid";
     }
 }