On the Cause of Damages of Side Screen Bulwark

Abstract

Recently in many ships some damages occurred at side screen bulwark. Typical plans of them are shown in Fig. 1. The cause of these damages seems to be related to the difference of the elongations of upper and lower decks. In this paper we study the mechanism, by which these damages occurred, about every case in Fig. 1 and analyse the stress distribution of several cases in order to explain that our studies are correct. In order to prevent these damages, the following measures seem to be effective.For (1), (2) and (3):- To taper the upper end of half round bar and extend them to the height just below the upper deck, not stopping them at the edge of bulwark plate. To make the radius of the corners of bulwark plate more than 250mm in order to avoid the sudden turn of half round bar.For (4), (5) and (6):- To reduce the breadth of side screen bulwark less than 200mm and set the stiffener along its center line. To connect the top angle and lower bulwark plate by close pitch rivets or by weld.Apart from these measures, it seems to be another measure to cut off the construction of side screen bulwark and make loose joint that the force may not be transmitted through this part at all.