Air carrier pilot reported receiving a terrain alert during approach. Flight crew corrected course and continued to landing.

Narrative

During the approach brief; I briefed the possibility of a change to visual approach to runway 15 from the river visual 19 approach. I briefed the necessary items for a visual approach using the RNAV 15 plate and taxi chart. I remember covering the nearly 3 degree offset of the course to the runway for the buildings on centerline.While we were between SUNEY and RORRK we were asked by tower if we could take the change to 15 for departure of company traffic on 19. We determined we were still in a position to accept the visual approach to runway 15. We accepted the transition to 15.Given that we were short on time; we didn't load the gps approach into the FMS. That contingency was pre-briefed. The runway and PAPIs were clearly in sight. While approaching the runway at roughly 1000' we received an EGPWS alert of 'obstacle; obstacle.' I determined that while lining up with the runway; I wasn't offset enough to avoid the buildings from setting off the EGPWS. As I did not hear the 'Pull Up' aural warning; I took positive corrective action by turning right and sidestepping the buildings to provide more separation between our aircraft and the buildings.Once clear of the buildings we landed without further abnormalities.One thing I feel I should note here: I think the PAPIs on 15 need readjusted. It was nearly impossible to maintain a two red/two white approach angle on the PAPIs. The PAPIs presented mostly either three white or three red during that approach and 15 approaches I have done since then.