As of noon today, 311 is awaiting replies from various entities who may be responsible for the blocked access.
I do not know what, if any, authority 311 has to address the problem, but their operator was already familiar with this issue, and receptive to my complaint.
Took previous poster's advice and contacted my City Counsel Person, via e-mail at her website.
Requested she dispatch a city employee with bolt cutters to remediate what appears to be an unlawful installation of gate and lock.