Bharasamarpanam is a process of explicit surrender which is done by Vadakalai sub-sect of Sri Vaishnavism. Bharasamarpanam or Bharanasyam is done after Samashrayanam
Is there any evidence of Purvaachrayas performing Bharasamarpanam(before the split between vadakalai and thenkalai sects occurred).
Note: Pancharatra Agamas approve of Bharasamarpanam so there is no doubt about its authenticity.