Tatiana García-Segura

Optimization of concrete I-beams using a new hybrid glowworm swarm algorithm

In this paper a new hybrid glowworm swarm algorithm (SAGSO) for solving structural optimization problems is presented. The structure proposed to be optimized here is a simply-supported concrete I-beam defined by 20 variables. Eight different concrete mixtures are studied, varying the compressive strength grade and compacting system. The solutions are evaluated following the Spanish Code for structural concrete. The algorithm is applied to two objective functions, namely the embedded CO2 emissions and the economic cost of the structure. The ability of glowworm swarm optimization (GSO) to search in the entire solution space is combined with the local search by Simulated Annealing (SA) to obtain better results than using the GSO and SA independently. Finally, the hybrid algorithm can solve structural optimization problems applied to discrete variables. The study showed that large sections with a highly exposed surface area and the use of conventional vibrated concrete (CVC) with the lower strength grade minimize the CO2 emissions.

Sustainable design using multiobjective optimization of high-strength concrete I-beams

Sustainable designs require long-term environmental vision. To this end, this study proposes a methodology to design reinforced concrete I-beams based on multiobjective optimization techniques. The objective functions are the economic cost, the CO2 emissions, the service life, and the overall safety coefficient. The procedure was applied to a simply supported concrete I-beam including several high-strength concrete mix compositions. The solution of this 15 m beam was defined by a total of 20 variables. Results indicate that highstrength concrete is used for long-term solutions. Further, the economic feasibility of low-carbon structures remaining in service for long periods and ensuring safety is proven. This methodology is widely applicable to different structure designs and therefore, gives engineers a worthy guide to enhance the sustainability of their designs.

Design Optimization Of Precast-prestressed Concrete Road Bridges With Steel Fiber-reinforcement By A Hybrid Evolutionary Algorithm

In this paper, the influence of steel fiber-reinforcement when designing precast-prestressed concrete (PPC) road bridges with a double U-shape cross-section is studied through heuristic optimization. A hybrid evolutionary algorithm (EA) combining a genetic algorithm (GA) with variable-depth neighborhood search (VDNS) is formulated to minimize the economic cost and CO2 emissions, while imposing constraints on all the relevant limit states. The case study proposed is a 30-m span-length with a deck width of 12 m. The problem involved 41 discrete design variables. The algorithm requires the initial calibration. Moreover, the heuristic is run nine times so as to obtain statistical information about the minimum, average and deviation of the results. The evolution of the objective function during the optimization procedure is highlighted. Findings show that heuristic optimization is a forthcoming option for the design of real-life prestressed structures. This paper provides useful knowledge that could offer a better understanding of the steel fiber-reinforcement in U-beam road bridges.

Computer-support tool to optimize bridges automatically

In bridge design, many variables like material grades, cross-sectional dimensions, passive and prestressing steel need to be modeled to evaluate structural performance. Efficiency gains are intended while satisfying the serviceability and ultimate limit states imposed by the structural code. In this paper, a computer-support tool is presented to analyze continuous post-tensioned concrete (PSC) box-girder road bridges, to minimize the cost as well as to provide optimum design variables. The program encompasses six modules to perform the optimization process, the finite-element analysis, and the limit states verification. The methodology is defined and applied to a case study. A harmony search (HS) algorithm optimizes 33 variables that define a three-span PSC box-girder bridge located in a coastal region. However, the same procedure could be implemented to optimize any structure. This tool enables one to define the fixed parameters and the variables that are optimized by the heuristic algorithm. Moreover, the output provides useful rules to guide engineers in designing PSC box-girder road bridges.

Valoración de las herramientas y metodologías activas en el Grado en Ingeniería de Obras Públicas

Los autores agradecen el apoyo recibido por la Universitat Politecnica de Valencia (Equipo de Innovacion y Calidad Educativa EXCELCON).

Heuristic Design Of A Precast-prestressed Concrete U-beam And Post-tensioned Cast-in-place Concrete Slab Road Bridges

This paper proposes simulated annealing and threshold accepting procedures for the automatic design of two different bridge types. Both cases are prestressed concrete road bridge decks typically used in public road construction. Simulated annealing is first applied to a precast beam of 30–30 meters of longitudinal spans and 12.00 m of width. The beam has a double U-shape cross-section and a beam spacing of 6 m. This problem involves 59 discrete design variables for the geometry of the beam and the slab, concrete grade, reinforcing steel and prestressing steel. The simulated annealing method indicates savings of about 5% with respect to a traditional design. The second bridge case is a 20–36–20 m posttensioned cast-in-place concrete slab road bridge deck. This example needs 33 discrete variables to define the complete structure. The threshold accepting method is used for the optimization. Our findings indicate savings of about 7.5% with respect to the design based on experience. Finally, the results show that heuristic optimization provides other options to reduce the design costs of real prestressed bridge decks.

Desarrollo y evaluación de la competencia transversal "pensamiento crítico" en el grado de ingeniería civil

La comunicacion presenta una metodologia para el desarrollo y evaluacion de la competencia transversal “pensamiento critico” en el grado de ingenieria civil, en el ambito de la asignatura “Procedimientos de Construccion II” de segundo curso. Se presenta una actividad de trabajo individual y en grupo basada en la discusion del procedimiento constructivo de un puente y de sus cimentaciones. Dicha actividad permite la evaluacion de la competencia de “pensamiento critico” basada en una rubrica, asi como la evaluacion de competencias especificas de la asignatura. Se ha realizado un analisis estadistico, de correlacion y de regresion lineal multiple de las calificaciones obtenidas en la actividad y en la prueba de evaluacion continua individual. Los resultados muestran como casi tres cuartas partes de los alumnos han alcanzado suficientemente la competencia. Sin embargo, los resultados muestran cierta desconexion entre los resultados relativos a las competencias especificas y los resultados relativos a la competencia transversal. Estas evidencias manifiestan que la adquisicion de la competencia transversal del pensamiento critico se ve favorecida por los trabajos de discusion en grupo. No obstante, la adquisicion de competencias especificas por parte de los alumnos requiere no solo de trabajos en grupo, sino tambien de trabajos individuales.