Multiobjective optimization of post-tensioned concrete box-girder road bridges considering cost, CO2 emissions, and safety

This paper presents a multiobjective optimization of post-tensioned concrete road bridges in terms of cost, CO2 emissions, and overall safety factor. A computer tool links the optimization modulus with a set of modules for the finite-element analysis and limit states verification. This is applied for the case study of a three-span continuous post-tensioned box-girder road bridge, located in a coastal region. A multiobjective harmony search is used to automatically search a set of optimum structural solutions regarding the geometry, concrete strength, reinforcing and post-tensioned steel. Diversification strategies are combined with intensification strategies to improve solution quality. Results indicate that cost and CO2 emissions are close to each other for any safety range. A one-euro reduction, involves a 2.34 kg CO2 emissions reduction. Output identifies the best variables to improve safety and the critical limit states. This tool also provides bridge managers with a set of trade-off optimum solutions, which balance their preferences most closely, and meet the requirements previously defined.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (BRIDLIFE Project: BIA2014-56574-R) and the Research and Development Support Program of Universitat Politecnica de Valencia (PAID-02-15).García Segura, T.; Yepes, V. (2016). Multiobjective optimization of post-tensioned concrete box-girder road bridges considering cost, CO2 emissions, and safety. Engineering Structures. 125:325-336. https://doi.org/10.1016/j.engstruct.2016.07.012S32533612

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Integrated framework for the sensitivity analysis of deployable planar scissor arches

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Parametric evaluation of deployable scissor arches

In a dynamic and evolving society there is a need for temporary and mobile structures. For this, deployable scissor structures - structural mechanisms that can transform from a compact state to a fully deployed configuration - are suitable. However, this transformational capacity complicates the design process since there is a strong interaction between geometry, kinematic properties and structural response. In the conceptual design phase there is a need for more structural insight related to geometric aspects of deployable scissor structures. Toward this end, this research evaluates the influence of design parameters (height, span, structural thickness, number of units, and scissor type) on the structural behaviour (stress, deflection and mass) of scissor arches. A sensitivity analysis is first performed which determines the relative influence of each of these parameters. Then a comprehensive parametric structural study is performed to determine the best values for efficient (low mass) scissor systems. The result of this research is a set of guidelines to facilitate the design of competitive scissor structures and enhance further analysis and realisation.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evaluation of design parameters for deployable planar scissor arches

info:eu-repo/semantics/publishe