Dynamic and Static Stability and Safety Limitations of Lift Slab Structures

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9504541 Masih Theoretical evidence as well as practical accidents have pointed out that under certain loading conditions the lift-slab structures are at the threshold static and dynamic instability. The instability of the structure is created by stacking the heavy mass of several slabs at high levels, while the structure cannot be braced laterally, since the bracing will inhibit the lifting process. During construction stage or under lateral loads, such an instability situation becomes highly undesirable. This project undertakes an investigation to the limitations within which the structure remains statically and dynamically stable. The project would also include a study of the ways and means of the safety precautions used and necessary recommendations to improve them. Theoretical studies to improve the design of lift-slab structure, performance against earthquake forces, and to recommend ways to strengthen the existing lift-slab structures to withstand possible future earthquakes will be conducted. Such improvement should help to avoid tragedies like those which happened in Armenia during the 1988 earthquake. Computer analysis will be made to study limitations as: the stacking schemes of the parked slabs, the safe relationship of those schemes with the geometry of the structure, the limits of safe dynamic load and its frequency to maintain safe lifting process, and the safe temporary connection of the parked slab to the columns. ***