An explosion on a typical offshore installation is a critical, however rare accidental event which may result in damage and loss of property, and in the worse case loss of lives. Top-side sections on an offshore installation which are exposed to an explosion blast should be designed to withstand such an event in a way that further escalation of the damage on personnel or property is avoided. There is however limited information on the modeling and analysis procedures for dealing with such events, and most classification rules on this subject give limited information and guidelines on the practical implementation of such effects for general analysis purposes. This thesis has been an investigation on these matters.The basis of this Master thesis has been on a pipe rack structure from one of Aker Solutions' top-side projects. It has been assumed that this structure is exposed to an accidental hydrocarbon explosion, and the resulting structural response has been investigated. A parameter study has been performed by varying blast load levels and durations. The effects due to the weight of the piping on the structure have also been studied. The main task of this thesis has been to compare simplified, static analysis models against dynamic analysis models as to calculate dynamic amplification factors (DAF), the purpose of this is to better understand the dynamic behavior of the structure due to the blast loading. The intention is that the dynamic amplification factors are to be used further by the engineers at Aker Solutions for dimensioning and designing of similar structures.Results showed that the blast loads as used in the analyses did not cause any structural responses within the material's plastic range. Further on, it was found that the magnitude of dynamic amplification is depending on both the blast duration emph{and} the weight of the pipes on the pipe rack. Typical results indicated that this dynamic amplification was reduced with increased blast duration.