Complex sentence: After the old bridge deck was demolished, the existing piers were retained but shortened, as the two eastbound lanes descend into the Franklin Tunnel east of the river in the new configuration, passing under the main Highway 63 lanes before connecting to Franklin Avenue.
Split into simpler sentences: After the old bridge deck was demolished, the existing piers were retained but shortened. The two eastbound lanes descend into the Franklin Tunnel east of the river in the new configuration, passing under the main Highway 63 lanes before connecting to Franklin Avenue.