Formwork system is a significant constituent and a basic requirement for high-rise cast-in-place reinforced concrete buildings. Usually, the builders are confronted with the decision to choose the safe, optimum number of levels of shores/reshores for a predetermined safety factor and given grade of concrete, giving due consideration to the cost of formwork system. In this study, MATLAB program is developed to calculate the load distribution between the interconnected slabs and levels of shore/reshore of a slab formwork based on a simplified method. This program is further modified by incorporating genetic algorithm for the optimization of cost of construction for high-rise building. The cost of level of shores and reshores per floor is defined as a function of cycle time which directly reflects the increase in the cost of construction. Various combinations of shore and reshore levels with several grades of concrete for various safety factors are checked to minimize the cost of construction. The optimization equation is solved using genetic algorithm considering appropriate constraints to practically ensure feasible solutions. The case of one level of shores and numerous levels of reshores is better than one level of reshores and numerous levels of shores. The result of certain combination of shore and reshore levels is not the same when the level numbers are reversed. A comparative study is carried out to check the optimum cost for various safety factors. The program is useful for the designers to decide the levels of shores and reshores with minimized cost without compromising the safety of construction.

ACI 209R-92. (1997). Predictions of Creep, Shrinkage and Temperature Effects in Concrete Structures. Committee 209 Report, American Concrete Institute, Farmington Hills, MI, USA, p. 4.

ACI 347.2R-05. (2005). Guide for Shoring/Reshoring of Concrete Multistory Buildings. Committee 347 Report, American Concrete Institute, Farmington Hills, MI, USA, p. 9.

Al-Tabtabai, A. L., Alex, H. A. P., & Jemes, R. (1999). Slab formwork design using genetic algorithm. Journal of National Research Council Canada, 8(3), pp. 2407-2418.

Al-Tabtabai, H. M. (2000). Genetic algorithm optimal model for slab formwork cost and design. Engineering Journal of the University of Qatar, 13, pp. 177-192.

ANSI10.9. (2003). Safety Requirements for Concrete and Masonry Work - American National Standard for Construction and Demolition Operations, p. 11.

Azkune, M., Puente, I., & Santilli, A. (2010). Shore overloads during shoring removal. Engineering Structures, 32, pp. 3629-3638.

Beeby, A. W. (2001). The forces in backprops during construction of flat slab structures. Structures and Buildings, 146(3), pp. 307-317.

Calderón, P. A., Alvarado, Y. A., & Adam, J. M. (2011). A new simplified procedure to estimate loads on slabs and shoring during the construction of multi-storey buildings. Engineering Structures, 33, pp. 1565-1575.

Coello, C. A. C., Christiansen, A. D., & Hernández, F. S. (1997). A simple genetic algorithm for the design of reinforced concrete beams. Engineering with Computers, 13, pp. 185-196.

Dongping, F., Haifeng, X., Xiaoming, W., Chuanmin, Z., & Tingsheng, Z. (2009). Load distribution assessment of reinforced concrete buildings during construction with structural characteristic parameter approach. Tsinghua Science and Technology, 14(6), pp. 746-755.

DSR 2016. (2016). Delhi Schedule of Rates. Central Public Works Department, Government of India, New Delhi, India.

Duan, M. Z., & Chen, W. F. (1995). Improved Simplified Method for Slab and Shore Load Analysis During Construction. Purdue University, West Lafayette, IN, USA.

Fang, D. P., Zhu, H. Y., Geng, C. D., & Liu, X. L. (2001). On-site measurements of structural characteristics of reinforced concrete buildings during construction. ACI Journal, 98(2), pp. 157-163.

Grundy, P., & Kabaila, A. (1963). Construction loads on slabs with shored formwork in multi-story buildings. ACI Journal Proceedings, 60(12), pp. 1729-1738.

Hanna, A. S., & Senouci, A. B. (1995). Design optimization of concrete-slab forms. Journal of Construction Engineering and Management, 121(2), pp. 215-221.

IS 456:2000. (2000). Indian Standard Plain and Reinforced Concrete - Code of Practice. Bureau of Indian Standards (BIS), New Delhi, India.

Jha, K. N. (2011). Formwork for Concrete Structures. Tata McGraw Hill Publisher, Delhi, India.

Kaveh, A., & Behnam, A. F. (2012). Cost optimization of a composite floor system, one-way waffle slab, and concrete slab formwork using a charged system search algorithm. Scientia Iranica Transactions A: Civil Engineering, 19(3), pp. 410-416.

Kaveh, A., & Shakouri Mahmud Abadi, A. (2010). Harmony search algorithm for optimum design of slab formwork. Iranian Journal of Science and Technology Transaction B: Engineering, 34(4), pp. 335-351.

Liu, X. L., Lee, H. M., & Chen, W. F. (1988). Analysis of construction loads on slabs and shores by personal computer. American Concrete Institute, 10, pp. 21-30.

Malasri, S., Halijan, D. A., & Keough, M. L. (1994). Concrete beam design optimization with genetic algorithms. Proceedings Arkansas Academy of Science, 48, pp. 111-115.

Nawy, E. G. (2008). Concrete Construction Engineering Handbook. CRC Press, Taylor & Francis, FL.

Rao, S. S. (1973). Minimum cost design of concrete beams with a reliability based constraint. Building Science, 8, pp. 33-38.

Sahab, M. G., Ashour, A. F., & Toropov, V. V. (2005). Cost optimization of reinforced concrete flat slab buildings. Engineering Structures, 27, pp. 313-322.

Senouci, A. B., & Al-Ansari, M. S. (1996). Optimum design of concrete slab forms. Engineering Journal of the University of Qatar, 9, pp. 79-93.