Axial shortening of columns due to long term creep and shrinkage is inevitable in tall reinforced concrete buildings. However, calculation of exact values of axial shortening is not a straight forward task since it depends on a number of parameters such as the type of concrete, reinforcement ratio, and the rate and sequence of construction. All these parameters may or may not be available to the design engineer at the preliminary design stage of construction. Furthermore, long term shortening of columns could affect the horizontal structural members such as beams and floors and hence could affect the finishes and partitions. Therefore, a reasonable idea about the probable axial shortening could be important for construction engineers and project managers as well. This paper presents a set of guidelines so that the effect could be taken into account approximately, especially at the preliminary design stage and also during the construction phase. In this study it is assumed, construction stage analysis considers the creep and shrinkage effects of a 40-story building consist of an exterior concrete frame and interior shear walls. The displacements of vertical members are evaluated and compared with the results from conventional analysis (Without construction stage).

1. Fintel, M. , and Khan, F. R. (1969). "Effects of column creep and shrinkage in tall structures-Prediction of inelastic column shortening", ACI Journal, Vol. 66, No. 12, pp. 957-967.
2. Henry G. Russell, ''Shortening of High Strength Concrete Members'', Special Publication, vol 121, 1990.
3. K. Sakata, T. Ayano, K. ImamotoAnd Y. Sato, ''Database of creep and shrinkage based on Japanese Research, RILEM and ACI, this is for JSCE and AIJ, 2005.
4. H. N. Praveen, Moragaspitiya, David. P. Thambiratnam, Nimalparera, Tommy H. T. Chen, "A numerical method to quantify differential axial shortening in concrete buildings", Engineering Structures, 32(8), pp. 2310– 2317, 2007.
5. Tsu-Te Huang, Rodney A. Stewart, Jeung-Hwan Doh,Dennis Song, ''Risk distribution profile for differential column shortening using a possibility theory approach, Fourth international conference on construction in the 21st century(CITC-IV), 2007.
6. O. Esmaili,S. Epackachi, M. Samadzad and S. R. Mirghaderi, "Estimation of long term vertical shortening of tall structure, Concrete Solution 09 paper 6b, 2008
7. Bazant and Z. P, "Practical predication of time dependent deformations of concrete", Material and structures, part I and II, Vol. 11, No 65 pp. 307-328; part III and IV, 1978
8. F. Mola, L. M. pellegrini, Effect of column shortening in tall RC buildings, 35th conference on our world in concrete & structures, 2010
9. Shieh, cang&jong, Structural design of composite super-columns for the Taipei 101 tower, Second Conference on Structural Steel Technology for Taiwan Strait Region. 2010.
10. HN Praveen Moragaspitiya, "A numerical method to quantify differential axial shortening in concrete buildings", journal of engineering structure, 2010 vol. 32 Iss. 8,pp 2310-2317.
11. ACI Committee 209, "prediction of Creep, shrinkage, and Temperature effect in concrete structure (ACI 209R-92)," American concrete institute, Farmington hills, Mich. ,1992, 47pp.

Axial Shortening Concrete Buildings Creep Shrinkage Construction Sequence And Deflection