spatial reference for I3S format to display in an ESRI web scene

I created a production in I3S format with a spatial reference of WGS84 and orthometric height.  I generated and spk file,  loaded it into ArcGis  Online and created a web scene  however the model displays  below the "ground".  Has anyone run into this and how was it corrected.  I looked at the Orlando sample created by Bentley and it displays properly on the base map.  Any help is appreciated

Farouk Rohoman