Just as context is important, so too are the various frames the inhabitants of that context choose to adopt. The series of bars welded on to the metal plate aren’t readily identifiable as intentional affordances (as opposed to more easily “perceived affordances”). Out of context and after working hours, there is essentially nothing that would tip an outsider off to this object’s designed function. Consider several ways this object could be subjectively framed, depending upon the motives of the individual doing the framing.
For drivers of the large cargo trucks that keep the construction site behind the gates functioning smoothly, it is a safety measure for their wheels to afford them additional traction under heavy loads.
For a construction worker, this plate may act as a physical (and mental) gateway, a tactile marker of entry into a new space, and a signal that he or she must recalibrate their thresholds of safety, sociability, etc.
For pedestrians, it is a caveat, introducing the possibility of the coming and going of massive, (over)loaded vehicles.
For an urban planner walking by, it may function as a reminder of the eventual need to redraw their mental map of that street/district/city to accommodate the structure being built there.
For a municipal work crew, it shelters the sidewalk beneath from the crushing loads of vehicles above, prolonging the length of the (nonetheless inevitable) cycle of wear and repair upon sidewalks.
For the cement salesmen, it is a thief.
What is this to you?