| what force act on a bridge? why must engineers be certain that these forces are balanced?

what force act on a bridge? why must engineers be certain that these forces are balanced?

iErO q asked:


what are balanced and unbalanced forces….

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One Response to “what force act on a bridge? why must engineers be certain that these forces are balanced?”

  1. vballnumbnutz on April 7th, 2009 10:34 pm

    Definately normal force from the surface(s) it is contacting, probably forces applied by the waves and the wind, weight of the object(s) that are on the bridge, weight of the bridge itself. If it is a suspension bridge; the tension of the cable holding the bridge together.

    If the net forces on the bridge is NOT zero, then the bridge will accelerate; meaning it starts to move. It either twists or sways.

    Engineers have taken into account all acceptable movement ie due to wind, thermal expansion, capacity, etc. If the movement goes beyond the “safety regulations” made by the engineer, the bridge will collapse.

    Something similar to the I-35W Mississippi River Bridge in Minneapolis during the summer of ‘07. A collapsed bridge also causes mental anguish to people; gephysrophobia/gephydrophobia - phobia of crossing bridges.