Recently, number of new constructions and engineering projects increased in Georgia, especially in Tbilisi, the capital of Georgia. Because of significant seismic activity of Caucasus region, seismic hazard assessment is very important issue for seismic-designing of engineering projects. Due to modern building codes, complex study of the local area is crucial for proper design of any type of constructions. Among them, following studies should be performed: probabilistic seismic hazard assessment, geological, geotechnical, geophysical, etc. After that, all information should be merged to each other and taken into account while designing of the project. In this paper, location of one construction site was selected as an application of complex study in order to show how can be merged different studies to each other. At the beginning, geological survey (well drilling) and geotechnical studies including laboratory tests were performed. Then geophysical profiling and downhole tests in wells were done by obtaining direct and shear wave velocities including estimation of physical-mechanical parameters. Next, probabilistic seismic hazard assessment and site-depended seismic hazard assessment were performed based on all information obtained by different studies. As a result, influence of local soil amplification on seismic hazard assessment is shown for the study area.