Which type of joints accommodate total motion ranges in excess of about 130 mm?

• A. Expansion joints
• B. Large movement joints
• C. Seismic joints
• D. Sliding joints

Answer: (B)

Joints are chosen based on how much relative movement they must accommodate between adjacent spans. When the total motion between deck segments is large—exceeding about 130 mm—you need a joint designed to handle that much travel. Large movement joints are built for big displacements, using modular or sliding elements that can telescope or slide relative to each other while still transferring loads and keeping out water and debris. They provide the necessary range for movements from temperature effects, differential settlement, or long-span expansion, without the seals or bearings failing under heavy travel. Expansion joints, seismic joints, and sliding joints each serve different ranges and conditions, but they aren’t optimized for such large total movements, which is why the large movement type fits this scenario.