Chapter 25 Flooring-Systems and Their Interaction with Usage of the Floor Lars Pedersen, Christian Frier, and Lars Andersen Abstract Some flooring-system designs might be sensitive to their vibrational performance, as there might be the risk that serviceability-limit-state problems may be encountered. For evaluating the vibrational performance of the flooring-system at the design stage, decisions need to be made by the engineer in charge of computations. On a flooring-system often passive humans and/or furniture are present. Often these masses and their way of interacting with the floor mass are ignored in predictions of vibrational behavior of the flooring-system. The paper explores and quantifies how these masses can influence central parameters describing the dynamic behavior of the flooring-system. Keywords Modal properties of floors • Floor dynamics • Numerical prediction • Serviceability-limit-state • Estimation accuracy Nomenclature f(k) Natural frequency M(k) Modalmass E Young’s modulus M Mass matrix (k) Damping ratio k Mode number Poisson’s ratio K Stiffness matrix !(k) Circular natural frequency n Scenario ·(k) Mode shape vector C Damping matrix 25.1 Introduction When designing flooring systems in buildings, the main focus often is on assuring that ultimate-limit state requirements are satisfied. For flooring systems this often relates to ensuring that a specified static load is acceptable. However there can be other issues apart from the static problem that can be problematic. This paper addresses vibration issues. For a floor, vibration problems can occur as a result of internal or external action. Internal actions may originate from humans in motion on the floor (persons walking), or from machinery placed on the floor area. This issue is addressed in [1]. External actions that can cause floor vibrations could be those arising as a result of nearby activities. This could be pile driving, trains running in a nearby metro system [2], road traffic [3] or similarly where structural and/or ground born vibrations end up bringing a floor of a building into vibration. In any case, the problem can be that humans on the floor can perceive vibration levels as annoying or sensitive equipment on the floor can be exposed to excessive vibrations. L. Pedersen ( ) • C. Frier • L. Andersen Department of Civil Engineering, Aalborg University, Sofiendalsvej 9-11, DK-9200, Aalborg SV, Denmark e-mail: lp@civil.aau.dk © The Society for Experimental Mechanics, Inc. 2017 J. Caicedo, S. Pakzad (eds.), Dynamics of Civil Structures, Volume 2, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-54777-0_25 205
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