We can't say whether the original design or the seismic retrofits had a flaw that could have been prevented.

我们不能说原始设计或抗震改造是否存在可以避免的缺陷。

Starting in 2000 and continuing all the way through 2015, seismic retrofits were added to the bridge to help it withstand a major earthquake and serve as a post-earthquake lifeline link for emergency vehicles and the public.

从2000年开始，一直持续到2015年，大桥进行了抗震改造，以帮助其抵御大地震，并成为应急车辆和公众的震后生命线。