We have selected rods rather than cables because these bridges are small and the loads to be supported are correspondingly low. Cables, if we were to use them, would be very small in diameter, which would make them vulnerable to vandalism. (查看原文)
...Thus, when we design a cable structure, our task is not to invent a form for the cable, but by means of the force polygon/funicular polygon pair to discover what shapes the cable will take under the assumed condition of support and loading, and to find among these shapes the one that best suits our needs. (查看原文)
On any force polygon/funicular polygon sysem subjected to vertical loads only, a ray drawn from the pole parallel to the closing string will divide the load line into the vertical components of the reactions at the ends of the funicular polygon. (查看原文)
Every parabola that is cut through by a closing string, regardless of whether the string is horizontal or sloping, has the property that lines tangent to the parabola at the points at which it intersects the closing string will intersect each other on the vertical centerline of the parabola. Furthermore, their point of intersection will occur at exactly twice the height of the parabola above the closing string, as measured on the vertical centerline. (查看原文)
作者: Edward Allen, Wacław Zalewski, Nicole Michel, Boston Structures Group 副标题: Designing Efficient,Expressive Structures isbn: 047017465X 书名: Form and Forces 页数: 620 定价: USD 131.21 出版社: John Wiley and Sons Ltd 出版年: 2009-10-23
