The device that connects the bridge superstructure with piers by pre-stressed concrete cables to prevent collapse during large earthquakes is:

• A. Guard rail
• B. Unseating Prevention System
• C. Expansion joint
• D. Bridge Collapse Prevention Device

Answer: (D)

During a powerful earthquake, keeping the deck tied to its piers is essential to maintain a continuous load path and prevent progressive collapse. A device that uses pre-stressed concrete cables to connect the bridge superstructure to the piers acts as a restraint system, tightening the connection so the deck cannot separate from or move excessively with the piers. The pre-stressing provides a clamping effect that remains active during large lateral motions, helping to hold the main structural elements in line and carry forces through the supports rather than allowing a loss of support or uncontrolled sway. This kind of system directly addresses the risk of collapse by enhancing redundancy and the ability to withstand seismic demands, making it the most appropriate option for improving collapse resistance.

Guard rails are safety barriers along the sides and don’t influence the structural load path during a quake. Expansion joints accommodate movement between spans or adjacent structures but don’t restrain the deck to the piers under large seismic forces. An unseating prevention system aims to stop the deck from lifting off supports but isn’t described here as linking the deck to the piers with pre-stressed cables. The term Bridge Collapse Prevention Device matches the role of providing that binding connection to prevent collapse under severe shaking.