the first and the second wall may also be evacuated in regions thus with the end wall module according to fig1 a it is the case of an end wall module with a first and second wall and respective rib structures wherein the rib structures are formed such that in the undeformed condition of the end wall module of installation shown in fig1 a the first and second rib structure are distanced to one another later it will be discussed see fig2 how given a bending load of the end wall module the oppositely lying webs 8 a and 8 b of the rib structures become engaged with one another the distance between the individual webs 8 a as indicated in fig1 a at x 1 is between 3 and 6 mm the web width t to be selected depends on the distance x 2 and the angle u03b1 of the web tips with u03b1 90 u00b0 as well as x 2 1 mm the minimal web width t is preferably larger than 3 mm all web pairs shown in fig1 a have identical dimensions fig1 b shows an alternative embodiment form of an end wall module 1 u2032 here a first wall 3 a u2032 and a second wall 3 b u2032 are likewise shown in contrast to the end wall module according to fig1 a the webs 8 a u2032 of the first rib structure 4 a u2032 in the direction perpendicular to the plane of the surface of the first wall 3 a u2032 do not have the same length but the webs here in an alternating and changing manner have different web lengths the same applies for the lengths of the webs 8.