We wanted a smart dynamic evaluation of form. We knaw that the forces of each knot i a system can be represented by a number of vectors. To achieve static equilibrium the sum of all vectors should be zero. it is relatively easy to describe all forces working at a given point, but it is a harder job to solve the linear algebra to make overall equilibrium of a larger structure. Especially when you want to change things and get the readings dynamically.

the greencoloured knots in the grasshopper file corresponds to the points in rhino. Only the left three points are programmed, the right are slaves, since the figure is symmetrical. The top line represents the bridge deck, the buttom points represents the end of the ribs, where one cable is attached.

The sum of the forces in a knot representet by the distance between the knot and a point drawn at the end of the summation vector is a visual indication of the resulting force in the point. by this method the resulting force changes instantly when the point is manipulated. In a more complex structure this manual aroach wil probably be to complex, but in our case we believe it will become useful, since grasshopper is a plugin to rhino, where we do almost all drawings of the bridge, and since we can make sliders for all input values.

the number slider represent the tension of the wire at the left initial section. Here there is static equilibrium - the red dods appear on top of each other.

The slider is set at a lower value, and the point representing the resulting forces drop below the knot to show, that the support from the cable gets insufficient. The distance between the knot and the resulting force is 10kN for one grid unit (one meter)

The funktion of he bridge weight has the constant weight of the bridge deck and central support and the weight of the rib that corresponds to a reference derived from the distance between the knot and the bridge deck.

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