Computational Technology Resources - CCP

Keywords: cost optimization, reinforced concrete beam, non-linear programming, multi-parametric optimization.

Summary

In the traditional design of reinforced concrete (RC) members a trial and error process is usually applied. An assumed cross-section is checked for strength, serviceability and other requirements of the design code. If the requirements are not satisfied a new cross-section is adopted and repeatedly checked. This design process does not take into account the cost of the structural element and thus usually leads to its unnecessary over dimensioning. However, to be competitive it is inevitable to take into account the cost of the structure. Structural optimisation is an effective technique that yields economical and rational design and leads to effective cost reductions.

The paper presents the cost optimum design of RC floor systems consisting of a RC slab supported by beams of rectangular cross-section. The goal of the research was to find out for which intermediate distances of the beams, i.e. which arrangement will be the whole floor system the most economical.

A detailed objective function of the floor systems manufacturing costs was given including the material and labour cost items. The manufacturing costs include the material costs of the concrete, reinforcement and formwork panels. The labour costs were added together from the costs of the cutting, placing and connecting of the reinforcement as well as from the labour costs for concreting, consolidating and curing of the concrete. The cost objective function is defined in an open manner and thus could be modified to take into account different economical conditions. The structural optimization was performed using the nonlinear programming approach, NLP. The beams and slabs were designed in accordance with Eurocode 2 for both the ultimate and serviceability limit states.

The comparative multi-parametric optimization was carried out for the combinations between six different spans from 3m to 8m, two different uniformly distributed live loads of 2 kN/m² and 5 kN/m² as well as three various distances between the beams from 4 to 8 m. For each combination of the above parameters (spans, loads and intermediate distances), the particular NLP optimization was performed the cost development of the entire floor system was investigated. The result demonstrated that the most economic design is obtained when the beams are arranged at a higher intermediate distances. This could help designers for choosing the competitive (optimal) structural design.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £130 +P&P)

	Computational & Technology Resources an online resource for computational, engineering & technology publications
	not logged in - login
Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 96 PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping and Y. Tsompanakis Paper 146 Competitiveness of Reinforced Concrete Floor Systems I. Merta¹ and S. Kravanja² ¹Institute for Building Construction and Technology, Vienna University of Technology, Austria ²Faculty of Civil Engineering, University of Maribor, Slovenia doi:10.4203/ccp.96.146 purchase the full-text of this paper Full Bibliographic Reference for this paper I. Merta, S. Kravanja, "Competitiveness of Reinforced Concrete Floor Systems", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 146, 2011. doi:10.4203/ccp.96.146 Keywords: cost optimization, reinforced concrete beam, non-linear programming, multi-parametric optimization. Summary In the traditional design of reinforced concrete (RC) members a trial and error process is usually applied. An assumed cross-section is checked for strength, serviceability and other requirements of the design code. If the requirements are not satisfied a new cross-section is adopted and repeatedly checked. This design process does not take into account the cost of the structural element and thus usually leads to its unnecessary over dimensioning. However, to be competitive it is inevitable to take into account the cost of the structure. Structural optimisation is an effective technique that yields economical and rational design and leads to effective cost reductions. The paper presents the cost optimum design of RC floor systems consisting of a RC slab supported by beams of rectangular cross-section. The goal of the research was to find out for which intermediate distances of the beams, i.e. which arrangement will be the whole floor system the most economical. A detailed objective function of the floor systems manufacturing costs was given including the material and labour cost items. The manufacturing costs include the material costs of the concrete, reinforcement and formwork panels. The labour costs were added together from the costs of the cutting, placing and connecting of the reinforcement as well as from the labour costs for concreting, consolidating and curing of the concrete. The cost objective function is defined in an open manner and thus could be modified to take into account different economical conditions. The structural optimization was performed using the nonlinear programming approach, NLP. The beams and slabs were designed in accordance with Eurocode 2 for both the ultimate and serviceability limit states. The comparative multi-parametric optimization was carried out for the combinations between six different spans from 3m to 8m, two different uniformly distributed live loads of 2 kN/m² and 5 kN/m² as well as three various distances between the beams from 4 to 8 m. For each combination of the above parameters (spans, loads and intermediate distances), the particular NLP optimization was performed the cost development of the entire floor system was investigated. The result demonstrated that the most economic design is obtained when the beams are arranged at a higher intermediate distances. This could help designers for choosing the competitive (optimal) structural design. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £130 +P&P)
Back to top	©Civil-Comp Limited 2023 - terms & conditions