I think this is the biggest spider of this species I have ever seen. It is also very ambitious, judging by its decision to build a web across a doorway to my friend's house.
I don't know enough about this species to interpret its behavior, but I suspect it is trying to repair damage caused by recent rain, as evidenced by the droplets on everything. Then again, it is fairly late in the day, and orb weaver spiders tend to eat their old webs before spinning a new one. In fact, as I was writing this, I stepped over the door for another look, and the spider has retreated to the door frame as if to take a nap.