Here's another interesting photo/design/failure. Note the highway bridging behind the failed section, which appears to be of similar design, but it didn't fail.
The foreground on the right appears to differ from the rear by pinning in the highway on the right, while the left slabs slid off their corbels / ledger, sliding to the left and dropping off the ledger. Vehicles on the far lane drove off the elevated highway, while those closer slammed into the exposed ledger.
It’s a directional thing. The Indian Plate moves horizontally north, sliding under the Asian, with nominal vertical motion. Someplace to the north there was probably vertical “bucking” similar to the Fukushima and the Banda Aceh which were vertical motion. It’s clear from the pics available so far that the primary motion was sideways-—just basically flinging the buildings sideways. One can only design for that by making a pretty good guess which way the shove is coming from. Incidentally, the roadway pics I’ve seen show much more sliding sideways than bucking.