“…Cremer and Heckl [1] gave a comprehensive summary of formulas for a number of simple structures, such as beams, plates and shells. Many authors, among them Dyer [2], Eichler [3], Beckmann [4], Heckl [5], Buhlert [6], Ljunggren [7] and Leung and Pinnigton [8], considered various point mobilities of plates in more or less detail. In contrast, very few results are published for point mobilities of more complicated or built-up structures; Lamb [9] and Goyder and White [10] studied beam sti!ened plates, while Peterson [11] addressed the point mobility at an intersection of two perpendicular plates.…”