BERKELEY, Calif.: The Biswas family was trying to sleep, but the group partying on the balcony a floor above them was too loud. At 12:42 a.m. Tuesday, they heard a crack and the building shuddered. Silvia Biswas jumped out of bed thinking an earthquake had struck and the apartments were about to collapse. When she looked out the window, she saw people lying on the ground. No one was screaming. The street was silent. Six people died and seven were injured when the balcony collapsed and sent them plummeting 40 feet to the ground. The victims were mainly students from Ireland working in the Bay Area for the summer. They were celebrating a woman’s 21st birthday.