Bridge Collapse FIU - Negligence?

Recently in the news, Flordia International University's bridge collapsed killing 6 people five days after the bridge was repaired. Workers had begun adjusting the tension in two rods threaded through diagonal bridge trusses on the north side, near the C-4 canal, just before the collapse. The collapse they claimed could have been due to the cracks in the concrete reported two days prior to the collapse. Engineers that did not partake in the construction of the bridge, claim due to the cracks tension between the rods could have adjusted causing the incident. A Miami-Dade police homicide squad is conducting a criminal investigation to determine whether any negligence occurred. But prosecuting such a case would be difficult, it will come down “to science and the experts.” Throughout history we see negligence taken place throughout countries from the violation of not punishing the violation of human rights and laws. So if negligence occurred what would the sentencing be?