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UPCommons - E-prints UPC Universitat Politècnica de Catalunya (82,639 recursos)
E-prints UPC cobreix dues finalitats: per una banda, és el dipòsit institucional de la UPC que recull els articles de revista, les comunicacions de congrés i els reports de recerca generats en les activitats de recerca del personal docent i investigador de la universitat; per l'altra, és una eina que permet accelerar la producció científica, allotjant versions de documents prèvies a la publicació en una revista o a les actes d’un congrés.

Articles de revista

Mostrando recursos 1 - 20 de 198

1. Seismic behavior of medium and high strength concrete buildings - Bairán García, Jesús Miguel; Moreno González, Rosángel; Peguero, J.
Current concrete technology has made higher concrete grades more affordable to mid and high-rise buildings; hence its use has been increasing in the late years as it allows for smaller cross-sections, reduction of the structure’s weight, improve durability, among other benefits. However, it is known that brittleness of plain concrete increases with the strength; therefore, some national codes have limited the concrete’s strength in high seismic zones. In this paper, the seismic behavior of a 10 storey dual frame-wall building, designed with concrete grades C30, C60 and C90 is studied in order to assess the advantages and disadvantages of this material...

2. Numerical analysis of the load-bearing capacity of brick masonry walls strengthened with textile reinforced mortar and subjected to eccentric compressive loading - Bernat Masó, Ernest; Gil Espert, Lluís; Roca Fabregat, Pedro
There is little research about the numerical modelling of brick masonry walls strengthened with Textile Reinforced Mortar (TRM) against second order bending effects. Thus, a numerical model has been implemented to cover this knowledge gap. It has been validated by comparison with experimental cases and applied to enhance the knowledge about the influence of different strengthening variables. The model is accurate at predicting the load-bearing capacity of walls and points out that strengthening both sides might cause a remarkable increase of the load-bearing capacity and that the performance of the TRM is greater for the most slender cases.

3. Preventive intervention in a group of building located in the histotic centre of Manresa (Barcelona) - Díaz Gómez, César; Cornadó Bardón, Còssima; Griera Cura, Antoni; Caselles Magallón, Josep Oriol; Alegre Heitzmann, Vicente; Santamaria Garcia, Pere
The preservation of old downtowns has become a necessity of growing interest. New urban policies have been approved in different countries in order to revive the old city centers and make them economically sustainable. In this global trend, the municipality of Manresa (Barcelona) developed an important urban planning operation in the old district that included the demolition of a group of existing buildings and the construction of a new modern one in close proximity to a group of old residential buildings which are cultural heritage of the city. As a consequence, specific areas of risk were generated which lead to...

4. Experimental and analytical study of concrete blocks subjected to concentrated loads with an application to TBM-constructed tunnels - Liao, Lin; Fuente Antequera, Albert de la; Pialarissi Cavalaro, Sergio Henrique; Aguado de Cea, Antonio; Carbonari, Gilberto
To generate enough thrust for a Tunnel Boring Machine (TBM) to excavate a soil and advance, several jacks are typically used to apply force to the last installed ring that acts as a reaction frame. These loads generate bursting stresses that might cause cracks in the longitudinal direction of the segments. Many studies dedicated to evaluate this phenomenon focus mainly on elements with similar height-to-length ratios. To cover the wide variety of dimensions and load application patterns, additional experimental assessments are required. The objectives of the present paper are to extend the study of with different height-to-length ratios subjected to...

5. Numerical prediction of the behavior, strength and elasticity of masonry in compression - Drougkas, Anastasios; Roca Fabregat, Pedro; Molins i Borrell, Climent
The paper focuses on the numerical prediction of the compressive response of masonry by means of detailed micro-modeling techniques. In such a model, the material constituents (mortar and units) and the unit-mortar interfaces are separately described by means of specific constitutive equations.; The available modeling choices are evaluated through a literature review of related case studies. A systematic approach is proposed and is corroborated by the numerical simulation of a large number of experimental cases from various sources. A total of fifty experimental results are simulated resulting in an overall good prediction of the compressive strength and elastic modulus of...

6. Numerical modelling with experimental validation applied to the study of stud connectors behaviour in concrete and steel composite structures - Bonilla, Jorge; Bezerra, Luciano M.; Larrúa, Rafael; Recarey Morfa, Carlos Alexander; Mirambell Arrizabalaga, Enrique
In this work, the behaviour of stud shear connectors in composite structures is studied, starting from the via numeric simulation of the push out test in a steel beam – with solid concrete slab concrete section is studied. The study considers material non-linearity material of concrete and steel, adopting firstly a bilinear model for both (steel and concrete), and in the second case, to the difference ofdiffering from other authors, the concrete damage plasticity of the concrete. ABAQUS is used to model the push out test. The basis and methodology of the modelmodelling process push out test are explained. The...

7. Double-punch test of fiber-reinforced concrete: effect of specimen origin and size - Aire, Carlos; Carmona Malatesta, Sergio; Aguado de Cea, Antonio; Molins i Borrell, Climent
One of the main advantages of the Barcelona test is that the properties of fiber-reinforced concrete (FRC) can be determined by using cylindrical specimens, thereby permitting the use of cores to control the quality of concrete used in construction.; Using the results of an extensive experimental campaign, this paper establishes the relationship between the unitary load of cracking, residual strength and toughness of molded specimens, and cores of concretes reinforced with different types of fibers but with the same aspect ratio. The fiber diameter is observed to signifidantly influence the properties of molded specimens, whereas in the cores, the number...

8. Computing voter transitions: The elections for the Catalan parliament, from 2010 to 2012 - Corominas Subias, Albert; Lusa García, Amaia; Calvet Puig, Maria Dolors
Purpose: To estimate the transition rates corresponding to the 2010 and 2012 elections to the Catalan Parliament for the four constituencies in which Catalonia is divided for this purpose. The main features of the results, which are obtained by means of mathematical programming, are commented. Design/methodology/approach: Mathematical programming optimization models are formulated in order to find the transition rates that yield a better adjust between the actual results in 2012 and those computed applying the transition rates to the 2010 results. The transition rate matrices are estimated for each one of the four constituencies, since the set of options is...

9. Effect of fine ceramic recycled aggregate (RA) and mixed fine RA on hardened propertiesof concrete - Etxeberria Larrañaga, Miren; Vegas, Iñigo
The ceramic industry is well known for producing large amounts of rejected ceramic waste. During the construction and demolition waste crushing process, a large amount of fine recycled aggregates (FRA) are usually produced. However, little research work has been carried out employing those types of aggregates in recycled aggregate concrete (RAC) production. In this research work, mixed and ceramic FRA in partial replacement of 10, 20, 35 and 50% of natural fine aggregates were used in order to verify their applicability in RAC manufacturing. All the concretes were produced to have the same workability. The physical, mechanical and durability properties...

10. Improved assessment of fibre content and orientation with inductive method in SFRC - Pialarissi Cavalaro, Sergio Henrique; López Carreño, Rubén-Daniel; Torrents Dolz, Josep M.; Aguado de Cea, Antonio
The inductive method is a robust and simple non-destructive test to assess the content and the distribution of steel fibres in FRC. Despite the advantages in comparison with other methods, further studies are still needed to define the accuracy, the theoretical basis and the equations for the conversion of the inductance into fibre content and distribution. In fact, although the test provides an indirect estimation of the fibre distribution, currently no equation exists for the assessment of the orientation number, which is a valuable parameter for the design of structures. The objective of the present paper is to address this...

11. Experimental study about the effects of granular skeleton distribution on the mechanical properties of self-compacting concrete (SCC) - Santos, Ana C. P.; Ortiz Lozano, José Ángel; Villegas, Noe; Aguado de Cea, Antonio
In recent years, the use of self-compacting concrete (SCC) has been increasing. Although methods for designing the mixture proportions usually derive from experience with conventional concretes, some specific procedures still are not universally accepted. The design and characterization of SCC influences not only the mix components (paste volume and nature, binder amount and type, granular skeleton, etc.) but also the testing methods used to validate the self-compactability (usually in terms of rheology, fluidity, viscosity and resistance to segregation). This paper studies the influence on SCC mechanical properties based on the consideration of two types of granular skeleton, discontinuous and continuous,...

12. Influence of barite aggregate friability on mixing process and mechanical properties of concrete - González-Ortega, Martha Alejandra; Pialarissi Cavalaro, Sergio Henrique; Aguado de Cea, Antonio
The main objective of this paper is to evaluate the friability of the barite aggregate during the mixing process and its influence on the fresh and hardened properties of concrete. Three types of aggregates were studied: barite (in two states, dry and wet), limestone and EAF slag. A specific test was designed in which each type of aggregate was exposed to several times of mixing to evaluate possible changes to the grading curves and in the surface of the aggregates grains. Moreover, four types of concretes were designed (two with barite, one with EAF slag aggregate and one with conventional...

13. Experimental analysis of properties of high performance recycled aggregate concrete - Gonzàlez Corominas, Andreu; Etxeberria Larrañaga, Miren
Due to the increase in the demolition of high strength concrete structures and the interest of precast concrete companies in being more competitive, it is necessary to analyse the use of recycled concrete aggregates (RCA) in high performance concrete (HPC). In this study, HPC were produced using 20%, 50% and 100% of RCA on substitution of natural coarse aggregates. Three types of RCA were used, they were produced crushing original concrete of 100, 60 and 40 MPa of compressive strength. The physical, mechanical and durability properties of the recycled aggregates concretes and conventional concrete were analyzed. The results showed that...

14. Properties of high performance concrete made with recycled fine ceramic and coarse mixed aggregates - Gonzàlez Corominas, Andreu; Etxeberria Larrañaga, Miren
There are various means of obtaining waste for the production of recycled aggregates. In this study the waste material has been obtained from building demolition and also from the ceramic industry (known for the production of large amounts of rejected ceramic wastes). High performance concretes (HPC) was produced using fine ceramic aggregates (FCA) in substitution of 15% and 30% of natural sand, and using 20%, 50% and 100% of coarse mixed aggregates (CMA) on substitution of natural coarse aggregates. The physical, mechanical and durability properties of the recycled aggregate concretes were determined and compared to those of the results of...

15. Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures - Kou, Shi-Cong; Poon, Chi-Sun; Etxeberria Larrañaga, Miren
In this paper, the effects of high temperature exposure of recycled aggregate concretes in terms of residual strengths, capillary water absorption capacity and pore size distribution are discussed. Two mineral admixtures, fly ash (FA) and ground granulated blast furnace (GGBS) were used in the experiment to partially replace ordinary Portland cement for concrete production. The water to cementitious materials ratio was maintained at 0.50 for all the concrete mixes. The replacement levels of natural aggregates by recycled aggregates were at 0%, 50% and 100%. The concretes were exposed separately to 300 °C, 500 °C and 800 °C, and the compressive...

16. Shear design of reinforced concrete beams with FRP longitudinal and transverse reinforcement - Oller Ibars, Eva; Marí Bernat, Antonio Ricardo; Bairán García, Jesús Miguel; Cladera Bohigas, Antoni
The shear resisting mechanisms of reinforced concrete (RC) beams with longitudinal and transverse FRP reinforcement can be affected by the mechanical properties of the FRP rebars. This paper presents a mechanical model for the prediction of the shear strength of FRP RC beams that takes into account its particularities. The model assumes that the shear force is taken by the un-cracked concrete chord, by the residual tensile stresses along the crack length and by the FRP stirrups. Failure is considered to occur when the principal tensile stress at the concrete chord reaches the concrete tensile strength, assuming that the contribution...

17. Shear-flexural strength mechanical model for the design and assessment of reinforced concrete beams subjected to point or distributed loads - Marí Bernat, Antonio Ricardo; Cladera Bohigas, Antoni; Bairán García, Jesús Miguel; Oller Ibars, Eva; Ribas, Carlos
A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction...

18. An algorithm for simulation of concrete cable-stayed bridges built on temporary supports and considering time dependent effects - Lozano Galant, Jose Antono; Turmo Coderque, José
The time-dependent phenomena effects might play an important role in the structural behavior of a cable-stayed bridge during construction and in service. In fact, because of these effects the target state of stresses (Objective Service Stage, OSS) can only be achieved at a certain target time. In the literature, a number of software have been presented to study creep and shrinkage effects during cantilever erection of cable-stayed bridges. Nevertheless, the effects of these phenomena in the alternative erection technique, the temporary support erection method, have received little attention. Furthermore, none of the presented software are able to: (1) Define a...

19. Creep and shrinkage effects in service stresses of concrete cable-stayed bridges - Lozano Galant, Jose Antono; Turmo Coderque, José
Most of the methods presented in the literature to define the target service stresses (Objective Service Stage, OSS) of cable-stayed bridges rarely include the time-dependent phenomena effects. Nevertheless, especially in concrete structures, this assumption might be on the unsafe side because time-dependent phenomena usually modify service stresses. To fill this gap, this paper studies the time-dependent phenomena effects into service stresses of concrete cable-stayed bridges. After illustrating the important role of these phenomena in an asymmetrical cable-stayed bridge without backstay, a new method to include their effects into the OSS is presented. An important issue to be considered in this...

20. Modification of the stress-state of cable-stayed bridge due to staggered erection of their superstructure - Lozano Galant, Jose Antono; Ruiz Ripoll, Lidia; Payá Zaforteza, Ignacio Javier; Turmo Coderque, José
In current practice, the effects of the evolutionary erection of cable-stayed bridge superstructure are rarely included into the simulation of its tensioning process. In fact, stay forces in service are usually defined in early stages of design, when the construction process has not even been conceived in detail yet. In order to fill this gap, the effects of the evolutionary erection of cable-stayed bridge superstructure throughout the tensioning process are studied in this paper. This study is focused on steel cable-stayed bridges erected on temporary supports. For the very first time a new criterion to include the effects of the...

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