Page 18 - DOUCE HYDRO 2013

18
ShockTransmission Units
AB Series
Shock Transmission Unit (STU), also called Dynamic Connector, is designed to be connected between
bridge structure components to form a rigid link under dynamic loads induced by forces such as vehicle braking
and earthquakes. At the same time, the structure will be able to move freely under slowly applied loads such
as thermal expansion and creep shrinkage.
The unit is connected between elements of bridge structures at expansion joints, or near the bearings between
the superstructure and the substructure.
The use of STU allows the load sharing of a suddenly applied force.
A
A special valve is fixed between the 2 chambers
F
X P1, P2 internal pressure into the chambers
V<Vcut : F<10% x Fmax (thermal expansion possible)
V>Vcut : F=Fmax (the structure is locked under a
minimal displacement)
STU acts as a very stiff spring in dynamic
loading (during earthquake or braking)
Working Principle:
A STU should block the deck of a bridge during a quick motion and behave like a spring with a very high stiffness
to reduce the displacement. At the same time, the Shock Transmission Unit should deliver a low reaction force
during the slow displacements of thermal expansion or contraction of the deck.
GENERAL
FVD: FLUIDVISCOUS DAMPER
STU: SHOCK TRANSMISSION UNIT
PSD: PRELOAD SPRING DAMPER
AVE SERIES
Vcut
V>Vcut