This research presents the development and implementation area of algorithms for geometric dimensioning rigid-foot-isolated reinforced concrete subjected to the under biaxial bending. The area algorithms are valid for square footing, homothetic to the pillar with equal Bludgers and a rectangular dimension unrelated to the pillar. In the development of algorithms, it is considered that the load is positioned within the central core footing inertia, i.e., applicable only in cases of small eccentricities. This issue is relevant when considering that normally the geometry of footing subjected to under biaxial bending with poor accuracy is calculated, resulting in inaccurate dimensions therefore may increase the cost of the element. In addition to the assumptions and analyzes used in the development algorithms, several numerical examples are shown to demonstrate their efficiency. Examples were prepared considering the concrete consumption for each geometric type of footing. Ultimately, a comparison is made between the results, setting the most economical type of geometry in terms of consumption of concrete.

A flexão oblíqua composta é definida pela ocorrência simultânea de força axial e momento fletor oblíquo. Para tal situação, as verificações de estado-limite último e de serviço possuem certa complexidade. O presente trabalho apresenta um método de cálculo dos esforços solicitantes da flexão oblíqua composta de uma seção transversal de formato poligonal em concreto armado ou protendido partindo de deformações impostas. Para isso, calcula-se a integral analítica da relação tensão-deformação para cada solicitação, partindo da relação entre as diversas variáveis que definem a forma e a relação constitutiva. Obtém-se uma equação para cálculo de cada solicitação interna, que são aplicadas para construção do diagrama de momentos resistentes para dada força axial, construção da relação momento-curvatura e verificações de serviço. Estas aplicações constam em forma de fluxograma e compilados num programa gratuito e aberto chamado OblqCalco, que é disponibilizado. Expõe-se exemplos destas situações obtendo resultados concordantes e exposto graficamente.

Este trabalho analisa a vida útil à fadiga da armadura longitudinal em vigas de pontes de concreto armado considerando-se o número real de veículos pesados de 2 a 6 eixos em um trecho rodoviário do estado de São Paulo, Brasil. Utilizou-se modelos teóricos com um sistema estrutural com pontes com duas vigas biapoiadas com vãos de 10, 15 e 20 metros. Para determinação dos esforços emprega-se o software Ftool e na estimativa da vida útil à fadiga o método do dano acumulado. Ao fim, verifica-se que o tempo de vida útil à fadiga da armadura longitudinal varia de acordo com o tamanho do vão, sendo que nas três pontes analisadas a vida de serviço à fadiga é inferior a 30 anos.

This paper provides an experimental investigation on the moment-rotation response of typical moment resisting beam-column connections, employing continuous negative bars consolidated with cast in place concrete over the precast beam and passing through grouted corrugated sleeves into an intermediate column. According to [1], the relative beam-column rotation is highly dependent on the elongation mechanism of the negative bars related to both the embedment length into the grouted sleeves and the development length over the beam end, being also inversely dependent on the vertical distance between the position of the top bars and the centre of rotation at end beam section. The flexural secant stiffness of the moment-rotation response is caused by a sum of the joint opening mechanisms at the beam-column interface and crack propagation within the connection zone, wherein the bond-slip at crack positions occurs prior to the first yielding of the negative bars. Therefore, the semi-rigid behaviour of the beam-column connections is associated with deformation mechanisms that occur at the SLS, but which also affects the global behaviour and stability analysis of precast frames at the ULS.Cruciform tests of full scale beam-column connections were carried out at the Precast Research Centre of the Federal University of Sao Carlos (Brazil), where 6 prototypes were studied varying the detailing of the positive connectors over the concrete corbel. The first pair of connectors employed elastomeric bearing pads with 2 vertical dowel bars, the second pair of connectors employed horizontal joints filled with grout with 2 vertical dowel bars and the last pair of connectors employed positive welded plates. The comparison between the experimental results showed that the smallest secant stiffness, which was obtained from the connector with elastomeric bearing pad, was corresponded to 89% and to 82% of the highest secant stiffness obtained for the connectors with welded plates and grouted joint, respectively. Therefore, the experimental results indicate that the major deformation mechanism within the beam-column connections is mostly dependent on the elongation of the top bars. Finally, a simplified analytical equation has been calibrated against the experimental results of the studied beam-column connections.

In project practice, the search for optimal solutions is based on the traditional process of trial and error, which consumes much time and does not guarantee that solutions found are the optimal solutions for the problem. Many studies have been developed in recent years with the aim of solving problems in various fields of structural engineering with the aid of intelligent algorithms; however, when it comes to the optimization of structural designs, the approaches considered by the authors involve a large number of variables and constraints, making the implementation of optimization techniques difficult and consuming significant processing time. This research aims to evaluate the efficiency of intelligent algorithms when associated with structural optimization approaches that are simpler to implement. Therefore, a Genetic Algorithm in Real Coding was built to serve as an auxiliary tool for pre-dimensioning prestressed concrete beams. With this, the problem becomes simpler to implement, as it depends on a smaller number of variables, leading to less processing time consumption. Simulations were performed to calibrate the Genetic Algorithm and find the optimal solution later. The solution found by the algorithm was compared with the real solution of a project that had already gone through a traditional optimization process. Even in these circumstances, the proposed Genetic Algorithm was able to find, in 210 s, a more economical solution. Our studies found that even with more straightforward approaches, intelligent algorithms can help in the search for optimal solutions to structural engineering problems; in addition, using real coding in fact proved to be a great strategy due to the nature of the problem, making the implementation of the algorithm simpler and ensuring answers with little processing time.