Determination of Actual Design Moment in Ultradeep Reinforced Concrete Rafts
by Muhammad Tariq Amin Chaudhary, Ph.D., P.E., M.ASCE, (3942 Acorn Crescent, Windsor, ON N8W 5R4, Canada. E-mail: mtariqch@hotmail.com)
Practice Periodical on Structural Design and Construction, Vol. 13, No. 4, November 2008, pp. 186-188, (doi: http://dx.doi.org/10.1061/(ASCE)1084-0680(2008)13:4(186))
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| Document type: |
Journal Paper |
| Abstract: |
This paper deals with determination of actual design moment in the flexural design of ultradeep reinforced concrete rafts. Due to diagonal crack in concrete, the workpoint of the internal tension-compression couple resisting the applied moment is shifted by a distance equal to the effective depth of the member. This shift in the workpoint necessitates that the design moment at a particular section shall also be shifted accordingly. The case is highlighted with the example of a 9.0 m (29.5 ft) deep circular raft that is acted upon by upward buoyant forces as well as downward gravity loads. Design moments in various regions of the raft increased by 1.3 to 248% after application of the moment shift rule described in the paper. The substantial increase in moment values signifies the importance of the phenomena for ultradeep reinforced concrete rafts. |
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