The expansion bearing is located at the bottom of the deck.
The expansion bearing is a rocker-type expansion bearing which consists of a pin at the top that facilitates rotations.
Caption: Figure 1: Photographs of the bridge system: (a) Chulitna River Bridge and (b) expansion bearing condition.
Researches in [5-7] demonstrated that the friction coefficient of expansion bearings together with other factors should be considered during the fragility analysis of the bridge system.
Typically, heavier duty conveyors have a non-expansion bearing placed on the drive end of the pulley and an expansion bearing
placed on the driven end.
A fixed bearing permits rotational movement and prevents translation in one or more directions, while an expansion bearing
permits both rotation and translations.
Valva elongate, with broad in distal part and round apex; costa expanded at basal 1/4 anteriorly, followed by deep emargination, then nearly straight beyond 2/5; ventral margin with 2 expansions sub-basally and medially, median expansion bearing dense setae; comb-like plate arising from beyond median expansion of ventral margin, short, as long as width of distal part of valva, slightly bent downward; apex round, with dense setae along termen; sacculus narrow, sclerotized, extending to middle of valva.
Valva elongate, wider basally, roundly expanded in distal part; costa strongly concave before middle and then straight obliquely; apex round; ventral margin nearly straight to middle, then strongly expanded; median expansion bearing dense setae; comb-like plate arising from middle of median expansion and terminate at its distal end; outer margin of distal part rounded; sacculus narrow, heavily sclerotized, extending to middle of valve, with dilated part at middle.
reinforced concrete decks with precast concrete deck planks and a waterproof bituminous overlay; cast-in-place median barriers, bridge parapets, and deck joints; repairing fixed bearings and replacing expansion bearings
with elastomeric bearings; and upgrading drainage and illumination systems.