How can you set webform to create a new relationship rather than update an expired relationship when the relationship type and person is the same?
This has been resolved in https://github.com/colemanw/webform_civicrm/pull/75

This PR provides a field on the Additional options tab under CiviCRM on your webform so you can set it on a per webform basis. If you check the box then if there is an existing relationship of the same type with the other contact then it will create a new relationship record with the new start date rather than updating the old one.