Evaluación del impacto económico del grado de acero de refuerzo y del tipo de empalme en el diseño de edificios con sistema estructural combinado con capacidad de disipación de energía moderada y especial

Abstract

Recently, worldwide, different investigations have been carried out that give viability to high-strength steel (steel grade 80 and grade 100), as an internal reinforcement of concrete and an alternative to traditional steel (steel grade 60), so much so that in the actualization of the document ACI 318-19, it included grade 80 steel for the design of reinforced concrete structures with a special and moderate degree of energy dissipation. In the same way, to replace the overlapping splices of the reinforcing steel, in recent years, due to construction facilities, the use of mechanical splices has also been implemented that allow linking two sections of steel bars, efficiently transmitting the stresses from one section to the other. other. Given the rise of high-strength steel, whose properties are already consigned in the structural design equations; which is already being used in constructions in different countries worldwide and which is expected to soon begin its production and use in Colombian territory, the present project was carried out that sought to evaluate the influence of the grade of reinforcement steel and the type of splice selected in the structural design of buildings in Colombia with a combined structural system of reinforced concrete walls and frames, for which an economic feasibility study was carried out that implies implementing in its design, grade 80 high-strength steel, also evaluate which type of splice satisfy better the requirements of each proposed case study, verifying the impact on the amounts of reinforcement required by varying the energy dissipation capacity between moderate (DMO) and special (DES). This evaluation was carried through the mathematical modeling of the structures in the ETABS software, in which the different structural models were carried out modifying the following five study variables: the yield strength of the reinforcing steel (grade 60 and grade 80), the type of splice for the reinforcing steel (lap splice and mechanical splices), the energy dissipation capacity (DMO and DES), the design spans (6 and 9 meters) and the number of floors (5, 10, 15 and 20 floors). From the commercial DC CAD program, the structural design was carried out and the quantities of steel and mechanical connectors of the primary elements (beams, columns and walls) were obtained according to each case study. For a better interpretation of the results, comparative graphs were made related to the amounts of reinforcing steel and the amount of mechanical connectors, with the respective costs, which are found in the annexes. Finally, when analyzing the results obtained in the structural modeling, it was found that the economic benefit of the use of grade 80 steel in the structural design is reflected only in the beams. Respect to mechanical connectors, the results show that these are a viable alternative exclusively in columns. In relation to the energy dissipation capacity, the estimated cost overruns were relatively low when designing with special energy capacity compared to moderate capacity, which is why it is favorable to design with DES to obtain better structural behavior, providing greater confinement and structural detail complying the requirements stipulated in structural design codes.