I-74 over Mississippi River

Design Challenges:

Uplift Restriction. R. J. Watson engineers had to take special consideration in the design of the disc bearings to accommodate a service uplift load of 102 kips, or 13% of the vertical load. Four of the bearings were designed to absorb lateral arch structure loads, while at the same time allowing rotation, and vertical, and longitudinal displacement. The solution was to use disc bearings oriented vertically, and they were called “Wind Tongue Bearings.”

Bearing Technical Information:

327 high load multi-rotational disc bearings with a vertical service load that ranged from 235 kips to 862 kips. The horizontal load ranged between 10% to 33% of the vertical load. The longitudinal displacement for the expansion bearings ranged from 5.25” to 16.125”, and the transverse displacement ranged from 0.250” to 4.5”. The service rotation varied from ± 0.015 radians to ± 0.020 radians.

Expansion Joint Technical Information:

R. J. Watson finger joints were installed at Piers 2, 3, 7, and 13 for a total of 526 linear feet. The finger joints were designed to accommodate 6” of total movement.