Earthquake Disaster Simulation of Civil Infrastructures. From Tall Buildings to Urban Areas

Adam Martínez, JM. (2017). Earthquake Disaster Simulation of Civil Infrastructures. From Tall Buildings to Urban Areas. Engineering Structures. 148:1-1. doi:10.1016/j.engstruct.2017.07.006S1114

Contribución al estudio de soportes de hormigón armado reforzados con angulares y presillas metálicas. Análisis del soporte y del nudo viga soporte sometidos a compresión centrada

Cada vez son más frecuentes las situaciones en las que resulta necesario el refuerzo de estructuras existentes. Sin embargo, las investigaciones relacionadas con este tema son más bien escasas, sobre todo cuando se trata del refuerzo y reparación de soportes de hormigón armado (en adelante HA). Los soportes de una estructura de edificación son los elementos que sustentan el conjunto de la estructura, por lo que los fallos en su comportamiento suponen un riesgo de colapso del edificio completo. Si a esto se une el hecho de que un porcentaje considerable de los daños detectados en estructura de edificación se localiza en estos elementos, queda de manifiesto el problema que implica la falta de recomendaciones de diseño y cálculo, así como de investigaciones relacionadas con el refuerzo de soportes de HA. Considerando que la técnica de reforzar soportes de HA mediante angulares y presillas metálicas es una de las más empleadas en la actualidad, coincidiendo además con que es una de las menos estudiadas hasta la fecha, queda de manifiesto la necesidad de estudiar el comportamiento de esta técnica de refuerzo. Con este objeto, se plantea la investigación "Estudio experimental y numérico de soportes de hormigón armado reforzados con perfiles metálicos sometidos a esfuerzos de compresión y flexo-compresión", financiada por el Ministerio de Ciencia y Tecnología de España con cargo al proyecto de investigación MAT 2003-08075, cofinanciado con fondos FEDER. Esta investigación se desarrolla en el Instituto de Ciencia y Tecnología del Hormigón (ICITECH) de la Universidad Politécnica de Valencia. La presente Tesis Doctoral, se engloba dentro del proyecto de investigación descrito en el párrafo anterior, y en ella se estudia el comportamiento de soportes de HA reforzados mediante angulares y presillas metálicas sometidos a compresión centrada. Se efectúa también el estudio del comportamiento del nudo viga-soporte, analizando diversos modos de resolver dicho nudo. A partir de los rAdam Martínez, JM. (2008). Contribución al estudio de soportes de hormigón armado reforzados con angulares y presillas metálicas. Análisis del soporte y del nudo viga soporte sometidos a compresión centrada [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1982Palanci

Determining corrosion levels in the reinforcement rebars of buildings in coastal areas. A case study in the Mediterranean coastline

This paper describes a study of the damage caused by corrosion to the reinforcement rebars of a 40-year old building used as a car park at a distance of 20 m from the sea. The corrosion levels of the building s structural elements, including beams, joists and columns were analyzed by optical and electron microscopy. Carbonation depths and chloride contents (Volhard method) of the concrete cover were measured in situ. EDX was used to analyze the condition of the reinforcement surfaces and the morpholog and composition of the oxides. A high degree of corrosion was observed in all the above elements, carbonation had reached the depth of the reinforcement in all the samples studied, and the concrete chloride levels were far in excess of the recommended maximums. The study of the reinforcement rebars revealed different types of oxides of varying morphologies, compaction and coloring according to chloride content. A comparison with previous studies allowed us to verify the presence of crystals of at least akaganeite, lepidocrocite and goethite.Moreno, JD.; Bonilla Salvador, MM.; Adam Martínez, JM.; Borrachero Rosado, MV.; Soriano Martinez, L. (2015). Determining corrosion levels in the reinforcement rebars of buildings in coastal areas. A case study in the Mediterranean coastline. Construction and Building Materials. 100:11-21. doi:10.1016/j.conbuildmat.2015.09.059112110

Limitations of Grundy and Kabaila s Simplified Method and Its Repercussion on the Safety and Serviceability of Successively Shored Building Structures

[EN] One of the most critical stages for a structure s safety is its construction process, and this problem is even more acute in buildings with reinforced concrete structures. These structures are usually built by shoring successive floors, so that the most recently poured floor rests on the lower floors by means of shores. It is therefore vitally important to have calculation tools available to estimate the loads to which the shores and slabs will be subjected in each stage of construction. A number of calculation methods have been proposed to date, of which the one proposed by Grundy and Kabaila in 1963 is the best known and most frequently used. This paper analyzes the limitations of Grundy and Kabaila s method by means of a parametric study of finite-element method simulations that identified a large number of situations in which this method presented unsafe results in terms of the estimated loads on slabs. In many situations, therefore, applying this method could gravely affect a building s in-service behavior and durability. The paper s final objectives are to make the reader aware of the limitations of Grundy and Kabaila s method and the need to use the more refined methods that are now available to estimate the loads on shores and slabs in reinforced concrete buildings under constructionThe authors would like to express their gratitude to the Spanish Ministry of Education, Culture and Sport for funding received under the FPU Program (FPU13/02466) and to the Generalitat Valenciana (GV/2015/063).Adam Martínez, JM.; Buitrago Moreno, M.; Moragues Terrades, JJ.; Calderón García, PA. (2017). Limitations of Grundy and Kabaila s Simplified Method and Its Repercussion on the Safety and Serviceability of Successively Shored Building Structures. Journal of Performance of Constructed Facilities. 31(5):1-2. doi:10.1061/(ASCE)CF.1943-5509.0001038S1231

Causes of damage to industrial brick masonry chimneys

[EN] From the early 19th to the middle of the 20th century, brick chimneys formed part of the industrial landscape. As technology advanced, factories were abandoned and became absorbed by the cities growing around them but masonry brick chimneys found a new role as part of the historical heritage. A large number of these structures are now protected buildings, which means they have to be maintained in a good state of conservation. Architects and engineers who have to assess the condition or retrofit these structures therefore need to be familiar with the different types of damage that can affect brickwork chimneys, and having access to a classification of the different types of damage they are prone to would be very useful to them. This paper classifies and describes the most common defects found in these structures, compiled after a close inspection of 538 Spanish industrial chimneys. The types of damage were classified according to: a) changes in the materials used in their construction, b) damage caused by repeated actions, c) damage due to extraordinary events, and d) damage caused by living organisms.López Patiño, MG.; Adam Martínez, JM.; Verdejo Gimeno, P.; Milani, G. (2017). Causes of damage to industrial brick masonry chimneys. Engineering Failure Analysis. 74:188-201. doi:10.1016/j.engfailanal.2017.01.014S1882017

Global research continues into strengthening structures against earthquakes

Earthquakes continue to shatter buildings and the people inside them. Jose Adam and Francisco Pallarés of Universitat Politècnica de València report on recent trends in seismic strengthening of building structures.Adam Martínez, JM.; Pallarés Rubio, FJ. (2015). Global research continues into strengthening structures against earthquakes. Proceedings of the ICE - Civil Engineering. 168(4):148-148. doi:10.1680/cien.2015.168.4.148S1481481684D’Ayala, D. F., & Paganoni, S. (2014). Testing and design protocol of dissipative devices for out-of-plane damage. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 26-40. doi:10.1680/stbu.12.00087Faella, C., Lima, C., Martinelli, E., & Realfonzo, R. (2014). Steel bracing configurations for seismic retrofitting of a reinforced concrete frame. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 54-65. doi:10.1680/stbu.12.00072Ghasemi, M. R., & Farshchin, M. (2014). Pareto-based optimum seismic design of steel frames. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 66-74. doi:10.1680/stbu.11.00090Ismail, N., & Ingham, J. M. (2014). Polymer textiles as a retrofit material for masonry walls. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 15-25. doi:10.1680/stbu.11.00084Khoshnoudian, F., & Hemmati T, A. (2014). Impact of structures with double concave friction pendulum bearings on adjacent structures. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 41-53. doi:10.1680/stbu.12.00001Yaman, T. S., & Canbay, E. (2014). Seismic strengthening of masonry infilled reinforced concrete frames with steel-fibre-reinforced mortar. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 167(1), 3-14. doi:10.1680/stbu.11.0007

A numerical study into the evolution of loads on shores and slabs during construction of multistorey buildings. Comparison of partial striking with other techniques

This paper contains a summary and evaluation of an experimental research project carried out at the ICITECH laboratories, Valencia, Spain. The project consisted of the construction of a full-scale building that included a process of shoring, clearing and striking (SCS). The experimental model was used as the basis for the development of a FE model, including an evolving calculation, with the objective of simulating the construction process used, as well as studying the evolution of concrete properties during the test. The FE model was verified with the results obtained from the experimental model. Two further FE models were then developed from the original model and used to simulate the construction of the same building using two different construction processes: one involving shoring and striking (SS) and the other shoring, re-shoring and striking (SRS). Finally, the SCS was compared to the SS and SRS processes, respectively, and an analysis was made of the advantages and disadvantages of each one. The paper breaks new ground in that for the first time ever a comparative study is made of the three most frequently used shoring techniques. (C) 2010 Elsevier Ltd. All rights reserved.The authors would like express their gratitude to the Spanish Ministry for Science and Technology for funding the project (BIA2004-02085) and also to the Encofrados J. Alsina, Copasa, Lafarge and Ros Casares companies for their invaluable cooperation.Alvarado Vargas, YA.; Calderón García, PA.; Gasch, I.; Adam Martínez, JM. (2010). A numerical study into the evolution of loads on shores and slabs during construction of multistorey buildings. Comparison of partial striking with other techniques. Engineering Structures. 32(10):3093-3102. doi:10.1016/j.engstruct.2010.05.028S30933102321

A numerical model with varying passive confinement for circular and elliptical concrete-filled steel tubular columns

[EN] In this work, a non-linear 3D numerical model to study concrete-filled tubular (CFST) columns is presented. The numerical model is capable to consider the passive confinement that occurs in the concrete core of CFST columns, under which an increase in the strength and ductility of the element is expected. Passive confinement is governed by the volumetric deformation of the concrete core and by the increment of concrete strength, so it was necessary to define both aspects in the constitutive model. In the volumetric deformation, the elastic and plastic components were included, the latter by using the Drucker-Prager model. Different values for the angle of dilatancy were defined for normal and high strength concrete. The model was validated by using experimental tests performed on stub columns and eccentrically loaded columns. In addition, different section geometries were tested. According to the results, the model was able to describe the non-uniform confinement that appears in the concrete core of CFST columns.Lacuesta Carrión, CD.; Romero García, ML.; Lapuebla-Ferri, A.; Adam Martínez, JM. (2018). A numerical model with varying passive confinement for circular and elliptical concrete-filled steel tubular columns. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 409-417. https://doi.org/10.4995/ASCCS2018.2018.7246OCS40941

Masonry bell towers. Dynamic considerations

[EN] The building of masonry bell towers was customary in Europe until the beginning of the twentieth century. At the present time, most of the work carried out on these structures involves either conservation or rehabilitation, owing to their considerable historical value. One of the forces that can have an influence on the behaviour of a bell tower is that caused by the turning/oscillation of the bells themselves. This is a dynamic force and may interact with the tower's natural frequencies. This paper describes the effect of bell-ringing on masonry towers. The towers are classified and a series of data are offered to characterise their behaviour. Finally, a procedure is described that permits an assessment to be made of this type of structure.Pallarés Rubio, FJ.; Ivorra Chorro, S.; Adam Martínez, JM. (2011). Masonry bell towers. Dynamic considerations. Proceedings of the ICE - Structures and Buildings. 164(1):3-12. doi:10.1680/stbu.9.00030S312164

Improving construction processes of concrete building structures using load limiters on shores

This paper analyses the redistribution of maximum loads using a system of load limiters on shores in which the limiters yield at a given load and thus reduce the maximum load absorbed by the shores. For this analysis a finite element modelling (FEM) of an experimental building was developed in which load limiters had been fitted to the shores to restrict their maximum load to a given value. This was designed to: (a) optimise slab construction costs by using shores of lower load-bearing capacities, (b) improve safety during the construction of consecutive concrete slab floors by reducing maximum loads and redistributing loads amongst the shores; and (c) increase structural efficiency by more efficient use of the materials employed due to load redistribution. It has been estimated that using load limiters in this way can reduce total shoring costs in a building project by between 30% and 40%.The authors would like to express their gratitude to the Universitat Politecnica de Valencia for funding this research project (PAID-06-11) and also to the Encofrados J. Alsina Company for their invaluable cooperation.Buitrago Moreno, M.; Alvarado Vargas, YA.; Adam Martínez, JM.; Calderón García, PA.; Gasch, I.; Moragues, JJ. (2015). Improving construction processes of concrete building structures using load limiters on shores. Engineering Structures. 100:104-115. doi:10.1016/j.engstruct.2015.06.007S10411510