Is it ok to install an elliptical pipe with the longer dimension in the vertical position? The city needs to replace an existing 18" drain tile but there is no room for a wider pipe. 18" x 27" elliptical pipe will work.
This type of elliptical pipe is made by RCP casters with the lift hole in the long axis. Get the the flow chart curves for various slopes to check hydralic capacity.
In addition to Civilperson's suggestions, also get the load bearing tables from the manufacturer. The short answer to your question is "probably yes" but check with the pipe manufacturer.