The coils rest on two beams of 15 x 15 cm crosssection and a length of t = 140 cm. The loaded length from each coil is r = 90 cm. With the extension of (t  r) = 50 cm and the load of 4.5 t the necessary section modulus for each beam is taken from the diagram in Figure 16 with about 280 cm³.
The beams have a section modulus of 513 cm³ (Table 1). Also the extension of 50 cm is well within permissible limits.
Figure 16: Required section modulus for timber beam bedding
dimensions in cm 
10 x 10 
12 x 12 
15 x 15 
20 x 20 
section modulus in cm³ 
152 
263 
513 
1217 
Table 1: Section modules of timber beams (with 3 % shrinkage)
