Influence of Different Structural Solutions for Dynamic Response of the Modernized Building

During modernization of the building where comfort threshold of people staying inside is exceeded we should solve the problem comprehensively. Implemented solution which fulfilled expectations of the designer is not always correct in the other (apparently similar) conditions. This paper describes an attempt to interference with the stiffness of the floors of a residential building in order to achieve comfort of people staying inside. It is disturbed by car passing the way located 20 meters from building. Investigated object is a two-storey apartment building with basement, typical for the '70s. It is characterized by compact design (block in the form of a cuboid) and low vertical stiffness of floors, where horizontal partitions (walls) are supported by identical system of walls. In the study it is discussed the desirability of interference with the construction of the building and 5 variants of floor structure were carried out. Those variants constituted reinforced concrete slabs with thicknesses of 10, 12, 14 and 16 cm as well as existing reinforced concrete slab supported by steel beams made of IPE 180 spaced every 2 m. This procedure was applied on every residential storey. Criterion to rank applied solution was comfort of the people staying inside the building according standard PN88 / B-02171 - Evaluation of vibrations influence on people in buildings. As follows from the analysis interference in floors stiffness in the present case does not bring the required results. The reason for this is that an essential component of the vibration of the building is its movement as a solid. Change in time of the configuration of internal components constitutes little impact on the comfort of the people staying inside. In addition, based on analysis of the responses floors of the building on two floors, it is concluded that even in the same building in the application of the solution (which in terms of static should be the same) construction does not always result in similar effects. The reason of different floor responses at different levels is that they are separated by elastic damped medium, which change boundary conditions seemingly similar structural components. An additional aspect is the path length of wave propagation affecting the amplitudefrequency characteristics of extortion of selected floor slabs. Therefore, repeating selected structure solution should only occur after completing the calculation.