Open access repos are available for a number of schools. For Harvard, go to https://dash.harvard.edu/ . For Caltech, you can find all author's work here: http://authors.library.caltech.edu/ . Try googling "<University> open access repository" to see if you can find it.

However, I couldn't get online access for the UC system, even though they have a policy and "plan". I suspect that things just take longer at public universities due to bureaucracy.

Moreover, none of the university repositories I've found do anything close to a good job of making the articles searchable. For example, even though all of my papers are available through Caltech, google only provides links to arXiv or the actual journal. This is actually the problem: if you can't google it, it may as well not be on the open internet at all.