抄録
Flat slabs are usually supported by rows of columns distributed at the vertices of a square. In this study several manners of column arrangements in the flat slab structure are compared. Comparison is made by means of the total bending moment M, which is obtained by Eq.1. For this purpose the slab is divided into two areas : the portion of the plate around the column (A in Fig.2) and the middle portion surrounded by the boundaries of the others. Considering the former as the circular plate leads to the the solution M_1 (Eq.3). For the latter M_2 (Eq.4) is obtained. In Figs. 4, 6, 8 the lines indicating M_2=0 are found in fairly good agreement with the boundaries of the portion A. The total bending moment M, provided by M_1+M_2, along the diagonal line of the slab is shown in Fig.5, in which the results given by the membrane experiment (Phot.1) and the finite element method are also presented. For various column arrangements at the vertices of regular triangle and hexagon etc., the total bending moments, M_1+M_2, are obtained in the same fashion. From the above discussion it is advised that the flat slab structures should have column arrangements with small middle portions.
