Arturo N. Fontán

Improved Optimization Formulations for Launching Nose of Incrementally Launched Prestressed Concrete Bridges

The conventional design process of a launching nose of an incrementally launched bridge is based on trial-and-error methods to reduce bending moment of prestressed concrete deck at the foremost support during launch. With this method, there is no guarantee that the obtained solution is the best among all the possible solutions, since they all depend on the experience and intuition of a designer, and they are also restricted by a limited number of possible iterations. Given that launched bridges constitute an important constructive typology, all the available capacities of design innovation should be incorporated, including numerical optimization. This research work proposes an objective and rigorous formulation to optimize the launching nose of a launched bridge under real constraints that a bridge designer can encounter in practice. Comparing the results obtained by conventional process and those obtained by optimization techniques allows us to verify that some of the assumptions considered in classical design methods of a launching nose are not based on any theoretical foundation. This fact demonstrates the utility of numerical optimization to improve a design.

Design optimization of steel portal frames

A computer code written by the authors at the University of Coruna and aimed to produce optimum design of portal frames is presented in this paper. The PADO software provides the least weight design for the most common types of planar frames. The code incorporates the complete set of constraints considered in the Spanish code of practice for steel structures. The software has a graphical interface to provide a user-friendly communication. Some application examples are presented in this paper to make clear the capabilities of PADO code.

VTOP. An improved software for design optimization of prestressed concrete beams

Optimum tendon layout of prefabricated prestressed concrete beams was an early application of design optimization methodologies. But most of the approaches found in the literature were not suitable to be implemented in real life bridge engineering. To fill the existing gap a research has been conducted in the past years by the authors to optimize prefabricated concrete beams formulating the problem in such a way that could be applied directly by bridge designers in beam and slab bridge decks. The software produced, labelled VTOP, contains the necessary capabilities for daily applications and possesses a user friendly graphical interface. This paper describes the problem formulation carried out and includes several examples to show the efficiency of the computer code implemented. Some of them are examples of single prefabricated concrete beams and also an example showing the overall analysis of a bridge deck and the subsequent optimization of the prefabricated beam subjected to the internal forces produced by the external loading is included in the paper.

Simultaneous Cross Section and Launching Nose Optimization of Incrementally Launched Bridges

The conventional design process of the launching nose of an incrementally launched bridge is usually based on parametric models with great limitations and the use of a trial and error technique to improve the design. Facing the disadvantages of traditional approaches, the use of numerical optimization techniques permits the development of objective, rigorous, and complete formulations. This work solves the design optimization problem of an incrementally launched prestressed concrete bridge during construction, searching simultaneously for the optimum cross section dimensions and the prestressing forces of the concrete deck, as well as the most adequate characteristics of the launching nose for the best economic solution. A computer code that allows the generation of a deck was developed, under real design constraints similar to those a bridge designer may encounter in practice. This code is very useful for preliminary phases of a project. The results obtained with this innovative formulation show the benefit of considering numerical optimization tools.

Shape Optimization Of Steel Standard Profiles

In this paper a specific application of shape optimization related with finding the optimal values of the internal dimensions of wide flange steel profiles. Two different problems have been solved in this piece of research by using a computer code SAFO written by the authors. This software has a user friendly graphic interface which allows the user to be comfortable with the code. According with the results of the research work carried out new series of wide flange profiles more efficient than the current one are included in this paper.

A computer code for finite element analysis and design of post-tensioned voided slab bridge decks with orthotropic behaviour

This paper presents a computer software which allows the generation of a complete structural model of a concrete bridge with a voided slab deck, a common design for medium span bridges. The code implements the orthotropic plate paradigm and provides a graphical user interface, which allows both preprocessing and post-processing, linked to a commercial finite element package. A description of the code is presented, along with the formulation of the orthotropic plate. Verification and comparison examples demonstrate the performance and features of the software and also the applicability of the formulation.

Shape Optimization of Steel Standard Profiles

In this paper a specific application of shape optimization related with finding the optimal values of the internal dimensions of wide flange steel profiles. Two different problems have been solved in this piece of research by using a computer code SAFO written by the authors. This software has a user friendly graphic interface which allows the user to be comfortable with the code. According with the results of the research work carried out new series of wide flange profiles more efficient than the current one are included in this paper.

PADO. A Computer Code For Design Optimization Of Steel Portal Frames

The paper described a software developed by the authors to optimize planar steel portal frames. Several morphologies and geometries can be tackled by the code including elements of tapered cross section. Loading considered are the whole set required by the Spanish code of practice. Additionally several mobile cranes can be also considered. The software interacts with the user by means of a graphical interface very friendly that can encourage the engineers to add this methodology to their design tools.