Researchers from Petrobras and LAMCSO/COPPE/UFRJ are currently involved in the development and implementation of a computational tool, based in Evolutionary Algorithms, for the synthesis and optimization of submarine pipeline routes. In this tool, randomly generated candidate routes are evaluated in terms of several criteria, incorporated in an objective (or fitness) function to take into account the relevant aspects that should be considered in the design of a route. A previous work [1] described the initial steps taken towards the development of such tool. In that work, attention was dedicated to the geometrical representation of a route, and to some of the terms of the objective function associated with a preliminary, global step of the optimization process (such as total pipeline length, and geographical-topographical issues associated with the route geometry and to the seabottom bathymetry and obstacles). Now, this work focuses in other aspects related to the structural behavior of the pipe, under hydrostatic and environmental loadings; more specifically, special attention is dedicated to the implementation of On-Bottom Stability (OBS) criteria such as the proposed in the RP-F109 code [2]. Case studies are presented to illustrate the use of the optimization tool and to assess the influence of the OBS criteria.

This work describes a computational tool, based on an evolutionary algorithm, for the synthesis and optimization of submarine pipeline routes considering the incorporation of on-bottom stability criteria (OBS). This comprises a breakthrough in the traditional pipeline design methodology, where the definition of a route and the stability calculations had been performed independently: firstly, the route is defined according to geographical-topographical issues (including manual/visual inspection of seabed bathymetry and obstacles); afterwards, stability is verified, and mitigating procedures (such as ballast weight) are specified. This might require several design spirals until a final configuration is reached, or (most commonly) has led to excessive costs for the mitigation of instability problems. The optimization tool evaluates each candidate route by incorporating, as soft and hard constraints, several criteria usually considered in the manual design (pipeline length, bathymetry data, obstacles); also, with the incorporation of OBS criteria into the objective function, stability becomes an integral part of the optimization process, simultaneously handling minimization of length and cost of mitigating procedures. Case studies representative of actual applications are presented. The results show that OBS criteria significantly influences the best route, indicating that the tool can reduce the design time of a pipeline and minimize installation/operational costs.

The most common method of pipeline installation in shallow water is the S-Lay method. In this method, the welded pipeline is supported by rollers on the vessel and the stinger, forming the over-bend. Then it is suspended in the water all the way to seabed, forming the sag-bend. The over-bend and sag-bend form the shape of an “S”. This work focus in modeling the interaction between pipeline and lay barge on the over-bend region, considering not only the contact between the pipeline and the launching structure, but also the tensioner behavior. Two numerical models are proposed: (a) a rigorous contact model that provides important information related to the consequences of impact between pipeline and rollers. These consequences can be dents to the pipe or tearing of the coatings; and (b) a model for the simulation of the tensioner behavior. This latter includes a delay between the instant that the tensioner is activated until it effectively starts working. It also considers how fast the tensioner can recover the desired tension level in the pipeline. Several simulations of actual operations are shown, in order to illustrate the application of the proposed model.

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A universalização dos serviços de saneamento é a principal meta das empresas do setor, desde a promulgação da Lei Federal Nº 14.026, em 15 de julho de 2020, que atualiza o Marco Legal do Saneamento Básico. A concretização do leilão de Privatização da Companhia Estadual de Águas e Esgotos do Rio de Janeiro (CEDAE) tem motivado discussões na sociedade que perpassam por política, economia, saúde pública e meio ambiente e, neste sentido, este trabalho vem lançar luz sobre a discussão. Este artigo apresenta dados históricos que retratam a importância da estatal para o saneamento a nível nacional e local, e compara dados de desempenho em quesitos de governança nesta e em outras empresas da iniciativa privada que atuam no ramo. Tais dados mostram que contratos de concessão, bem redigidos, com objetivos bem delimitados e especificação de direitos e obrigações das partes envolvidas, podem ser extremamente benéficos à sociedade e podem contribuir para que o objetivo final do Marco Legal seja alcançado: a universalização dos serviços de saneamento até 2033. A importância do tema analisado neste artigo vai além do notório impacto positivo do saneamento na vida da população, mas provoca uma reflexão acerca da desestatização destes serviços sob a ótica da governança e eficiência técnica.