The research presented in this thesis endeavors to improve upon the Simplified (Extended) Method for the calculation of shoring/reshoring schedules, while maintaining its ease of use and practicality. The method developed assumes the parameters discussed below, most of which are contrary to those of the Simplified (Extended) Method. (1) The loads applied to the underlying shores are not necessarily uniformly distributed. (2) Shores are not infinitely stiff. (3) The relative stiffness of different age slabs has a contributory effect on the distribution of loads between shores, reshores and slabs. (4) The foundation (at the first level of shores) may not be completely rigid and the load distribution in the shores and slabs above may be affected by the foundation stiffness.
During construction of reinforced concrete flat slab buildings, a freshly cast slab relies on the slabs below it for support. The Simplified Method assumes that this weight is more or less equally shared by all supporting slabs. A methodology was developed to determine more realistic load ratios supported by the slabs in the shoring and reshoring system. A basic description of this methodology is presented below (1) The stiffness characteristics of flat slabs for unit point loads applied at desired shoring and reshoring patterns were determined and stored in an array format in Microsoft Excel 2007. (2) After the stiffnesses at each shore/reshore locations were determined, equations were developed which describe the relationship between slab deflections (function of slab stiffness), shore loads and forces in reshores (unknown). (3) Parameters such as reshore stiffnesses, age adjusted slab stiffnesses, foundation stiffness, determination of load ratios applied to shores from freshly cast slab (i.e. tributary area vs. detailed analysis) and concrete creep and shrinkage were examined.
The work in this thesis shows that neglecting reshore stiffness in calculating shoring/reshoring schedules is an erroneous assumption. Conclusions regarding the importance of taking into account reshore stiffnesses are provided below. (1) Neglecting the elastic stiffness of reshores greatly overestimated the average load supported by reshores for all cases studied. (2) Neglecting the elastic stiffness of reshores generally overestimates the load supported by individual reshores. (3) Using infinite reshore stiffness provided a reasonable approximation of the maximum reshore loads. (4) Neglecting reshore stiffness significantly underestimated the total load supported by the top slab in the reshored system.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/29448 |
| Date | January 2007 |
| Creators | Monette, Luc Jean-Guy |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 158 p. |
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