diff --git a/src/app/calculators/parallel-structures/parallel-structures.config.json b/src/app/calculators/parallel-structures/parallel-structures.config.json
index 0a1504b21786497a7b0a66dc9ba7eeab0abe8384..7ad7220356096c69b137d9fd54ce0edcd7034248 100644
--- a/src/app/calculators/parallel-structures/parallel-structures.config.json
+++ b/src/app/calculators/parallel-structures/parallel-structures.config.json
@@ -32,6 +32,7 @@
                     "VanneRectangulaire_GateCem88d": "structures/cem_88_d.html",
                     "VanneRectangulaire_GateCem88v": "structures/cem_88_v.html",
                     "Orifice_OrificeSubmerged": "structures/orifice_noye.html",
+                    "Orifice_OrificeFree": "structures/orifice_denoye.html",
                     "SeuilRectangulaire_WeirSubmergedLarinier": "structures/fente_noyee.html",
                     "SeuilRectangulaire_WeirFree": "structures/kivi.html",
                     "SeuilTriangulaire_TriangularWeirFree": "structures/dever_triang.html",
@@ -52,7 +53,8 @@
             "ZRAM",
             "alpha2",
             "BT",
-            "ZT"
+            "ZT",
+            "Zco"
         ]
     },
     {
diff --git a/src/locale/messages.en.json b/src/locale/messages.en.json
index 896554a7a145ed42c645e12d82357a4a01fe8916..3dffe393904b2cc14068fa1b3547bc3dbc600a1a 100644
--- a/src/locale/messages.en.json
+++ b/src/locale/messages.en.json
@@ -273,6 +273,7 @@
     "INFO_LIB_Z": "Water level",
     "INFO_LIB_Z1": "Upstream water level",
     "INFO_LIB_Z2": "Downstream water level",
+    "INFO_LIB_ZCO": "Orifice center elevation",
     "INFO_LIB_ZDV": "Crest weir elevation or gate base",
     "INFO_LIB_ZF2": "Downstream bottom elevation",
     "INFO_LIB_ZRAM": "Upstream apron elevation",
diff --git a/src/locale/messages.fr.json b/src/locale/messages.fr.json
index 82647a3b73f1b164b64b520b02acecab4d728be8..0c195e665f6f7bb78d9bb9ebfaf8ce752a64d2f7 100644
--- a/src/locale/messages.fr.json
+++ b/src/locale/messages.fr.json
@@ -272,6 +272,7 @@
     "INFO_LIB_Z": "Niveau d'eau",
     "INFO_LIB_Z1": "Cote de l'eau amont",
     "INFO_LIB_Z2": "Cote de l'eau aval",
+    "INFO_LIB_ZCO": "Cote du centre de l'orifice",
     "INFO_LIB_ZDV": "Cote de la crête du déversoir ou du radier de la vanne",
     "INFO_LIB_ZF2": "Cote de fond aval",
     "INFO_LIB_ZRAM": "Cote du radier amont",