Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Two distinct sections of research are presented in this thesis. The first section summarizes research conducted on laboratory-built floors. Floors were built and tested to determine the plywood contribution to increasing the bending stiffness, number of joists effective in resisting applied load, and calculation of fundamental frequency. The second section summarizes research conducted on in-situ floors. Procedures were developed to numerically integrate acceleration and velocity data to obtain displacement values. Tests were conducted on 86 subjectively rated wood floors to determine average frequency and peak displacement values. From these tests, a design criterion was developed to predict acceptability of a wood floor system to vibrations. / Master of Science

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M.Ing. / This research project was initiated by a well-known international company (MAKRO SA), which had experienced floor joint problems occurring in their industrial floors. Floor joint problems i.e. joint damage and spalling of the joint area result, from a combination of construction workmanship and quality control problems, as well as from operational hard wheeled vehicle loading conditions. Damaging and spalling of joint edges are general problems occurring on warehouse floor slabs because of hard wheeled loads trafficking joints. In addition, joint filler detachment from the joint wall surface looks aesthetically poor and leaves the possibility of hygienic problems developing. In the case of MAKRO SA stores, the above problems are not acceptable and should be avoided at all costs. The objective of the report is to investigate solutions to solve the problem of joint damage in industrial floors due to problems occurring in practice, as described below. Floor joint edge problems are a result of three main reasons. First, subsoil quality. The quality of the subsoil is determined by the compaction effort and type of filler materials used, which in turn determine the amount of deflection that will be detected at joint edges. Subgrade quality determines whether deflection of the top concrete layer will occur. Poor compaction and filler material contributes to excessive deflection occurring due to inadequate support of the concrete floor slabs. Water penetration through the floor slab results in the fines of the subsoil being eroded or washed out, resulting in a less dense material, which will deflect under large vehicle and store racking loads. It is concluded that good quality subsoil conditions will result in less deflection and level irregularities of the top concrete floor slab, resulting in less joint damage and spalling. Secondly, the effect of floor and joint workmanship on damage and joint edge spalling. Level irregularities occur due to poor troweling or floating efforts at the joint area. Poor joint edge workmanship results from incorrect formwork removal from the joint wall resulting in a damaged joint edge and additional spalling of the joint to that occurring from wheel load impact. Joints undergo damage as forklifts traffic the joint area as wheel load and energy

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This thesis investigates the footfall excitation of higher modes of vibration in low-frequency floor structures. This is motivated by the increased number of floors reportedly failing to meet the required occupants comfort level although being designed in accordance with the current state-of-the-art design guidelines. In particular modern, lightweight, and slender floor structures. The contribution to knowledge of this thesis can be summarised as: quantifying the signal energy of measured walking forces within and above the natural frequency cut-off proposed by the current state-of-the-art design guidelines; quantifying the contribution of higher modes of vibration to the overall response of low-frequency floors to human walking; propose measures to judge the response nature of low-frequency floors, these are the relevant change of the point stiffness and the shape of frequency response functions; proposing a frequency-domain approach that enables designers to include higher modes of vibration in the design against human-induced vibration. It was found that the signal energy of walking forces is distributed well beyond the natural frequency cut-off proposed by the current state-of-the-art design guidelines. Also, the contribution of localised, higher, modes of vibration to the overall response of ultra-lightweight floors was significant. Moreover, it was found that higher modes affect the response of floors of various construction types in one way or another. Hence, it was recommended to consider their contribution in the design of floors against human-induced vibration. Also, it was found that the higher the relative change of the point stiffness the more higher modes contribute to the overall response of floors. Finally, the frequency-domain analysis was found less expensive than time-domain analysis and could result in similarly useful information.

Typescript, etc. / Digitized by Kansas State University Libraries

published_or_final_version / Civil Engineering / Master / Master of Philosophy