In this thesis a plug cementation of a 16" casing string is investigated. What happened was that during primary cementing of a 16" casing string at a depth of 2440 m, the string failed. It was assumed that the bottom plug plugged the float valve and thus the cement column was immediately stopped on its way downhole (water hammer phenomenon). Task was to investigated if this water hammer effect causes a suffiecent high load to damage the casing string. It could be figured out that the string faced a maximum load of 61,53 bar but out of this only 11,3 bar were generated by the water hammer. The remaining 50,3 bar were caused due to the hydrostatc difference between the annulus and the casing. Further it could be proved that larger casing sizes do not increase the impact of a water hammer. Concerning pipe dimensions the ratio between wall thickness and inner diameter is decisive. The whole study is supported with a simulation software called Wanda 3.