During the past few decades, nondestructive damage evaluation (NDE) techniques are widely applied in industries, such as architecture, power plant equipment, and mechanical manufacture, etc. non-destructive damage detection techniques being applied to experimental data where it becomes a hotspot and challenging matter. Each of the NDE methods developed to date can be classified into different levels according to their performance and application. This paper will focus on the application of a Two Points-Condensation (TPC) technique. The TPC technique this method detect the damage based on vibration. The TPC technique reduces the structural system to two degrees of freedom system. The current stiffness matrices obtain from optimization the equation of motion of two degree of freedoms system using the measured test data. The current stiffness matrices compare with original (undamaged) stiffness matrices. The large percentage changes in matrices' coefficients lead to the location of the damage. The improvement occurs in the reduction method, where the static condensation method replaced by the system equivalent reduction expansion process (SEREP) condensation method that provides a dependable result. The method allows fewer sensors than those required in the mentioned methods. The technique is applied to the experimental data of a steel truss bridge model structure after inducing the damage by removing an element from the specimen. The results show that the method detects the damage location area.