Fig. 3.3.2.2 shows the definition for a reinforced concrete shell with two faces with different thicknesses, materials and reinforcement definitions. The geometry corresponds to that of fig. 3.3.2.1. A standard reinforced concrete cross sections consists of five layers: Layer zero is the concrete cross section. The layers one to four correspond to reinforcement. The top layer (with respect to where the local z-axis points to) comes first, the bottom layer last. Their orientation with respect to layer zero is 0°, 90°, 90° and 0°.