We are designing a new website template with a global navigation and a child-site navigation. It looks like we are going to use the hamburger icon as the action button to display the menu. One idea that has come up is to use the icon twice, once in each bar, one of them displaying the global nav, one displaying the site nav. Roughly like this:
Are there any existing patterns or sites which could prove that this is a reasonable idea? Or are there specific reasons for not doing this?