Frank Schanack | Universidad Austral de Chile (original) (raw)

Papers by Frank Schanack

The Indian Concrete Journal, Jan 2009

Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In... more Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In contrast to tied arch bridges with vertical hangers they are mainly subject to axial forces and only little longitudinal bending, leading to possible savings of more than 50% of structural steel. Despite or maybe because of this amazing claim, few network arches have been built. It is the professional experience of the authors that when a network arch is proposed as an alternative to the conventional tied arch bridge with vertical hangers, the responsible persons request an extensive demonstration of its benefits. In this article the authors present a comparative study of conventional tied arch bridges and network arch bridges. Subsequently, the basic structural behavior of a network arch is explained by means of a parametric study of the radial hanger arrangement. This paper concludes that the longitudinal bending moments are about ten times smaller in a network arch than in a tied arch bridge with vertical hangers, leading to important material savings.

Мостостроение мира 2'2008, 2008

ICTB2013–Las Vegas 2nd International Conference on Timber Bridges, Institute for Transportation at Iowa State University, 2013

In certain cases the concrete slab of wood concrete composite beams can crack; deformations will ... more In certain cases the concrete slab of wood concrete composite beams can crack; deformations will
increase and the internal forces will be redistributed. At present, the design recommendations
available vary from ignoring the effect to reducing stiffness by 60%.
In order to characterize more correctly the influence of the concrete cracking on the force
distribution in wood concrete composite beams a research project was conducted involving
theoretical analysis and laboratory tests. First, a parameterized nonlinear FEM model was
elaborated and calibrated by real test data available from the literature. Second, shear tests were
conducted with test specimens that simulate the concrete cracks by a small separation between the
concrete and the timber. The results indicate that the concrete cracking does not only reduce the
stiffness of the concrete slab itself but also leads to a significant stiffness reduction of the shear
connectors embedded in it.

ARCH'04, 4th International Conference on Arch Bridges, 2004, 2004

Network arches have inclined hangers that cross each other at least twice. It seems to happen mor... more Network arches have inclined hangers that cross each other at least twice. It seems to happen more often for railway bridges than for road bridges that structural elements above the bridge deck are acceptable, which justifies investigations of the applicability of network arches. The tie can be a longitudinally prestressed concrete slab. This gives less noise, and the additional self-weight favours the structural behaviour. Alternatives with steel and composite bridge decks are discussed. For double track railway bridges spanning up to 100 metres the arches can be rolled H-sections. For larger spans welded box sections are applicable. For the design of network arches the hanger arrangement is important. Small bending moments in the arches and small hanger forces are obtained when the upper hanger nodes are placed equidistantly and all hangers cross the arch with the same angle. The cross angle's size depends on several parameters. Hints for a good choice are given. The maximum hanger forces vary little, thus all hangers have the same cross-section. To ensure passenger comfort and the stability and continuity of the track, deformations of railway bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic. A network arch railway bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties.

ARCH'04, 4th International Conference on Arch Bridges, 2004, 2004

Network arches are bowstring arch bridges with inclined hangers that cross each other at least tw... more Network arches are bowstring arch bridges with inclined hangers that cross each other at least twice. The use of many hangers reduces bending in the arch and tie and therefore they can be made very slender. Network arches are likely to remain the world's most slender arch bridges. This publication is about the erection of this very efficient structure. For distances between the arches of less then 18 m the tie should be a concrete slab. The tensile force is taken by longitudinal prestressing cables. The arch is very slender. In many cases the small bending moments and the efficient support against buckling by the hangers favours the use of universal columns or American wide flange beams. In the network arches in Norway the tie was cast on formwork resting on timber piles in the riverbed. The arch and hangers were erected from the concrete lane. The hangers were tightened with great care till the arch carried the tie. A light temporary lower chord is suggested to obtain a steel skeleton with enough strength and stiffness to carry the casting of the permanent concrete tie. During erection the steel skeleton can be moved when lifted at the end of the spans. The temporary lower chord can be reused for many spans or modified for different projects. If the network arch is the main span over a navigable waterway, the steel skeleton can be erected on the approaches and be lifted in place by a pontoon or a crane. If the steel skeleton already has the correct shape, no further adjustment of hanger is necessary. In cold climates the steel skeleton can be erected on ice and lifted onto the abutments. Network arches are very efficient structures. They need less structural steel than other bridges. Efficient methods of erection can make them very economical.

Wood Research, 2005

Pinus radiata D. Don growing in Chile, South America, was hydro thermally treated and tested. Wit... more Pinus radiata D. Don growing in Chile, South America, was hydro thermally treated and tested. With an increase of the temperature or the time of treatment an increase on mass loss and a reduction on wood density were determined. A reduction on bending strength and MOE was also detected. The maximum swelling (after conditioning in a water bath) increased and the pH value of water extracts decreases considerably with increasing temperature. The hydrothermal treatments produced a considerable colour change, the wood was turning darker.

11o CONGRESO INTERNACIONALPROVIAL - Valdivia 2014 - Gestión y Patrimonio Vial, 2014

A base de una inspección visual, sin medios de acceso especiales, de los 600 puentes que forman l... more A base de una inspección visual, sin medios de acceso especiales, de los 600 puentes que forman la red vial pública de la Región de Los Ríos, se determinaron sus evidentes daños y deficiencias. Los resultados permiten evaluar el estado de conservación particular de cada puente y en general de los puentes de la Región. Entre los daños más frecuentes se destacan: “No existe / no funciona barrera de contención”, “Separación entre tablones de resistencia”, “Longitud de mesa de apoyo menor que 0,7m + 0,005L”, “Contención del relleno del estribo ineficiente” y “Junta permeable en calzada”. En general, el estado de conservación es bajo y existe una gran cantidad de puentes que requieren a una acción de mitigación inmediata. Esto no es posible dada la cantidad limitada de recursos, por lo que es preciso flexibilizar los criterios de evaluación. Sin embargo, se recomienda el uso de señalética, como restricciones de carga, de velocidad, entre otros. Un problema especialmente severo presentan los así llamados puentes provisorios, los puentes de madera. En la Región de Los Ríos existen 185 puentes provisorios y casi todos presentan alguna deficiencia o daño grave. Considerando además que los puentes provisorios deben ser sustituidos cada 4 a 8 años debido a la descomposición de la madera, esta tipología resulta ser el eslabón más débil dentro de la gestión de la conservación de los puentes.

11o CONGRESO INTERNACIONALPROVIAL - Valdivia 2014 - Gestión y Patrimonio Vial, 2014

Puentes de madera son un elemento importante de la red vial Chilena, dado que aproximadamente un ... more Puentes de madera son un elemento importante de la red vial Chilena, dado que aproximadamente un 20% de todos los puentes carreteros son de este material. Sin embargo, debido a problemas de durabilidad en las tipologías usada habitualmente, los puentes de madera son considerados ser de una calidad inferior; de hecho se catalogan como puentes provisorios. Una tecnología atractiva que extiendo sustancialmente la vida útil de los puentes de madera son las vigas mixtas madera-hormigón, donde las vigas de madera son protegidos por una losa impermeable de hormigón armado. Además, la combinación estructural de ambos materiales conduce a otros beneficios, como una mejor distribución lateral de la carga, la reducción de la armadura necesaria, una menor deformación y mejores propiedades dinámicas. En el marco de un proyecto de investigación, se han realizado ensayos en laboratorio para determinar los parámetros estructurales necesarios para un dimensionamiento de un puente mixto de madera-hormigón bajo normativas vigentes en Chile. En concreto, se ha diseñado un puente de 15 m de luz y 10 m de ancho, para tráfico vehicular sin restricciones, con 7 vigas de madera laminada encolada y una losa de hormigón de 18 cm de espesor. La comparación de este puente con otros puentes definitivos con similares dimensiones demuestra que los costos económicos son muy similares.

11o CONGRESO INTERNACIONALPROVIAL - Valdivia 2014 - Gestión y Patrimonio Vial, 2014

Dentro de una red vial existen numerosos puentes que normalmente presentan algún grado de daño y/... more Dentro de una red vial existen numerosos puentes que normalmente presentan algún grado de daño y/o deficiencia. Dentro de la tarea de conservación de puentes, se deben realizar trabajos de mantención para eliminar los daños, corregir las deficiencias o mitigar los efectos que ambos puedan causar. Normalmente, el costo de la ejecución de todos los trabajos de mantención necesarios supera el presupuesto anual para la conservación de puentes del cual dispone una administración pública. Para el mejor aprovechamiento de los recursos se propone un algoritmo de priorización que tiene en cuenta tanto el grado de daño de cada puente en particular, como también su importancia dentro de la red vial. El grado de daño se determina mediante una inspección del puente y está relacionado con el tiempo máximo recomendado hasta que tenga que ocurrir la corrección del daño. La importancia es determinada a base de 5 criterios: ancho del puente, TMDA, existencia de rutas alternativas, número de habitantes afectados y restricción de peso máximo. El algoritmo y la ponderación de cada criterio han sido calibrados mediante la aplicación a los 600 puentes de la red vial de la Región de Los Ríos. Para ello se programó el Sistema de Gestión de Puentes, una aplicación web para la gestión de datos. Mediante el algoritmo desarrollado se puede tomar decisiones de priorización de mantención basado en criterios objetivos.

Volume 84, 1 February 2015, Pages 362–367, 2015

Concrete cracking in timber–concrete composite beams causes a stiffness reduction of the concrete... more Concrete cracking in timber–concrete composite beams causes a stiffness reduction of the concrete and increases deformations and stresses. The consideration of this effect in design is indispensable, because otherwise an unsafe design is obtained. However, existing design recommendations range from ignoring the effect to suggesting a 60% stiffness reduction of the concrete. A comparison of FEM simulations and reported bending tests reveal that the concrete cracking alone, as proposed in state-of-art literature, is not sufficient to explain measured stiffness reductions. The connector’s slip modulus must be decreased as well when cracking occurs. In novel laboratory shear tests, small gaps simulating the concrete cracking show that the slip modulus can decrease by more than 70%. A comparison of laboratory beam tests with FEM analysis show that initial stiffness and crack initiation is predicted correctly by the standard’s recommendations. However, the FEM results are only conservative if the connectors’ slip modulus is additionally decreased by 60%, when concrete cracking is observed.

Behaviour of Steel Structures in Seismic Areas STESSA 2012, 2012

The February 27, 2010 Chile earthquake is currently the sixth strongest earthquake measured in t... more The February 27, 2010 Chile earthquake is currently the sixth strongest earthquake measured in
the world. There was important damage to the road infrastructure and more than 200 bridges were damaged.
One of the bridges with severe damage was the Cardenal Raúl Silva Henríquez Bridge over the River Maule
in Constitución. This 912.5 m long composite girder bridge showed pier inclination, deck drift, bracing buck-
ling, seismic stopper damage and so on. The most particular damage was found at the fixed bearings at the
abutments. There, the steel girders are directly welded to an anchorage plate, which is anchored to the abut-
ment wall. During the earthquake, the longitudinal seismic forces caused the rupture of the lower flange and
the web of the steel girder leading to the failure of the bearing. This failure was analyzed by both a global and
a detailed FEM model in ABAQUS analysis software. It was possible to replicate the observed damage very
close to reality and to determine the corresponding forces. These results are very useful for the design of the
bridge rehabilitation and for future bridge projects.

V Congreso de ACHE, 2011

El articulo detalla los principales aspectos del proyecto del Puente en Arco sobre el Río Tercero... more El articulo detalla los principales aspectos del proyecto del Puente en Arco sobre el Río Tercero, que tiene por objeto el cruce del río del mismo nombre, vinculando las ciudades de Villa María y Villa Nueva (provincia de Córdoba, Argentina), en reemplazo del puente metálico que se encuentra adyacente al emplazamiento del nuevo puente. La tipología de arco tipo Network empleada para salvar el cauce del río Tercero permite salvar una luz de 120 m con una esbeltez de tablero y de arcos muy notable, junto con una economía de materiales significativa. Se ha desarrollado una solución totalmente prefabricada (tanto en los arcos metálicos como en las vigas longitudinales y transversales de hormigón pretensado) que permite acometer un proceso constructivo rápido y eficaz. Particularmente se ha profundizado en el análisis de estabilidad lateral de los arcos, con arriostramientos tipo Vierendeel.

XVII Jornadas Chilenas del Hormigón, 2009

Para el refuerzo de estructuras de hormigón se utilizan desde hace unas dos décadas hormigones r... more Para el refuerzo de estructuras de hormigón se utilizan desde hace unas dos décadas
hormigones reforzados con fibras de vidrio o carbón, que tienen las ventajas de la
anticorrosividad y de una alta resistencia a pesar de su pequeño espesor. Para
aprovechar estas propiedades de material también para la construcción de nuevas
estructuras, se desarrolló en Alemania un nuevo tipo de material: el hormigón con
armadura textil. Basado en estudios bibliográficos y la propia experiencia del autor
principal se analiza el potencial de este material.
La armadura textil se fabrica de fibras de vidrio o carbono de espesores de pocos
micrómetros. Desde varios cientos hasta más de mil de estas fibras se juntan en hilos,
los así llamados rovings. Los rovings tienen un diámetro de alrededor de 1 mm y
pueden ser colocados en tejidos multiaxiales que forman la armadura del hormigón. El
hormigón se fabrica con áridos finos de 1 a 4 mm de diámetro máximo para adaptarse
al tamaño de los rovings. Al final, el espesor económico de partes estructurales de
hormigón con armadura textil es de 2 a 3 mm hasta unos pocos centímetros.
Este nuevo material permite estructuras de hormigón con espesores mínimos, poco
peso propio, anticorrosivas, que se adapta bien a encofrados de doble curvatura y que
son altamente impermeables. Estas propiedades hacen que el producto, que no
compite directamente con el clásico hormigón armado con acero, enriquezca la gama
de materiales de construcción, especialmente en el campo de estructuras livianas. En la
actualidad el hormigón con armadura textil está siendo aplicado a pasarelas, botes,
elementos de fachada, cubiertas, muebles, etc.
En Chile la aplicación del hormigón con armadura textil puede ser especialmente
interesante para la arquitectura de estructuras livianas y como elemento de fachada en
la edificación.

Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In... more Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In the last five years there has been built a significant number of network arch bridges, maybe initiating a turning away from the traditional tied arches with vertical hangers. When introducing new structures it is important to understand well its structural behavior in order to assure the usual safety and quality level. In arches, the buckling behavior is of particular interest. The existent solution does not explain the in-plane buckling of network arches to a satisfying extent, limiting its application range to a special case. A general parametric study of the in-plane buckling leads to a concept, which allows considering the problem as a curved compression strut with radial elastic support. Then, a simple analytical formula is derived that predicts the critical buckling load and buckling mode for in-plane buckling of network arch bridges with an error of less than 5%.

Calculation of the critical in-plane buckling load of network arches., 2009

Netzwerkbögen sind Stabbogenbrücken mit geneigten Hängern, die sich mehrmals kreuzen. In den letz... more Netzwerkbögen sind Stabbogenbrücken mit geneigten Hängern, die sich mehrmals kreuzen. In den letzten fünf Jahren wurde eine bedeutende Anzahl von neuen Netzwerkbogenbrücken gebaut und vielleicht eine Abwendung von den traditionellen Stabbögen mit vertikalen Hängern eingeleitet. Wenn neue Tragwerke in die Bautechnik eingeführt werden, ist es wichtig, ihr Tragverhalten zu verstehen, um das gewohnte Sicherheits- und Qualitätsniveau zu wahren. In Bögen ist in diesem Zusammenhang das Stabilitätsverhalten von besonderem Interesse. Die einzige existierende Lösung kann das Knicken von Netzwerkbögen in ihrer Ebene nicht in befriedigendem Maße erklären, da ihr Anwendungsbereich auf einen Sonderfall begrenzt ist. Eine allgemeine Parameterstudie des Knickens in Bogenebene führt zu einem Konzept, nach dem das Problem als ein gekrümmter Druckstab mit radialer elastischer Bettung aufgefasst werden kann. Es wird daraufhin eine einfache analytische Formel hergeleitet, die die kritische elastische Knicklast und die kritische Eigenform mit einem Fehler von weniger als 5% voraussagt.

Calculation of the critical in-plane buckling load of network arches.

Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In the last five years there has been built a significant number of network arch bridges, maybe initiating a turning away from the traditional tied arches with vertical hangers. When introducing new structures it is important to understand well its structural behaviour in order to assure the usual safety and quality level. In arches, the buckling behaviour is of particular interest. The existent solution does not explain the in-plane buckling of network arches to a satisfying extent, limiting its application range to a special case. A general parametric study of the in-plane buckling leads to a concept, which allows considering the problem as a curved compression strut with radial elastic support. Then, a simple analytical formula is derived that predicts the critical buckling load and buckling mode for in-plane buckling of network arch bridges with an error of less than 5%.

Stahlbau, 2009

ABSTRACT Asymmetrische Netzwerkbögen eröffnen dem entwerfenden Ingenieur neue gestalterische Mögl... more ABSTRACT Asymmetrische Netzwerkbögen eröffnen dem entwerfenden Ingenieur neue gestalterische Möglichkeiten bei gleichzeitig guter Wirtschaftlichkeit und hoher Effizienz des Tragwerks. Im Gegensatz zu Stabbogenbrücken mit vertikalen Hängern befindet sich die Stützlinie in Netzwerkbögen ohne Hängerausfall für alle Lastfälle im Bogen. Daher muss die Bogenform nicht einem bestimmten Lastfall angepasst werden und kann asymmetrisch sein. Voraussetzung ist, dass auch dann eine Hängeranordnung entworfen wird, die Hängerausfall vermeidet. Die Schrittgrößen und die technische Machbarkeit entsprechen im Wesentlichen denen von symmetrischen Netzwerkbögen. Mögliche Anwendungsgebiete umfassen asymmetrische Brückenstandorte sowie schiefwinklige Brücken und Brücken mit veränderlicher Breite.Asymmetric network arch bridges.Asymmetric network arch bridges offer new possibilities to the design engineers. At the same time they ensure both, economic and static efficiency. In contrast to tied arch bridges with vertical hangers, in network arches without hanger relaxation the line of thrust lies within the arch for all load cases. Therefore, the arch shape does not have to be adapted to a special load case and may be asymmetric. The requirement for this is, that a hanger arrangement is designed, which avoids hanger relaxation. Internal forces and technical feasibility are basically the same as in symmetric network arches. Possible applications are asymmetric bridge locations, skew bridges or bridges with variable width.

Asymmetric network arch bridges offer new possibilities to design engineers. At the same time, th... more Asymmetric network arch bridges offer new possibilities to design engineers. At the same time, they ensure both economic and static efficiency. In contrast to tied arch bridges with vertical hangers, in network arches without hanger relaxation, the line of thrust lies within the arch for all load cases. Therefore, the arch shape does not have to be adapted to a special load case and may be asymmetric. In order to design an asymmetric network arch, a hanger arrangement that prevents hanger relaxation has to be found. Internal forces and technical feasibility are basically the same as in symmetric network arches. Possible applications are asymmetric bridge locations, skew bridges or bridges with variable width.

Journal of Bridge Engineering, 2010

This work describes some of the most important results of the experimental and numerical analyses... more This work describes some of the most important results of the experimental and numerical analyses of Escaleritas Viaduct, Spain. Before the inauguration of this composite cable-stayed bridge in 2006, the bridge authority required a dynamic load test identifying, for instance, the natural vibration modes, the dynamic magnification factor, and the maximum vertical acceleration. The dynamic test was accompanied by numerical simulation performed in two different three-dimensional finite-element models, one of them composed of 145,000 shell elements. The correlation of test and analysis data is good and allows several interesting general conclusions to be drawn. It is shown that Escaleritas Viaduct complies with the requirements on the dynamic structural behavior defined in the standards.

Bautechnik, 2015

Despite of widely implemented advances in TCC bridge technology, there are still no satisfying de... more Despite of widely implemented advances in TCC bridge technology, there are still no satisfying design recommendations that consider the influence of concrete cracking on the distribution of forces and deformation. A research project at Universidad Austral de Chile studied several aspects of concrete cracking in TCC bridges with timber beams of greater depth than width using elastic dowel-type shear connectors. One of the results of concrete cracking is a reduction of the slip modulus of the connectors. This weakening was simulated in shear tests by a small gap between the timber and the concrete. A test calibrated FEM model was used for a parametric study of 120 different cases, most of which did not show concrete cracking. Where concrete cracking occurred, it caused an increase in the timber tensile stresses and beam deflection of up to 20 %. We conclude that concrete cracking occurs when the timber-concrete depth ratio is less than four times the cubic root of the effective flange width of the concrete slab.

Beitrag zur Berücksichtigung des Einflusses der Rissbildung im Beton in Holz-Beton-Verbundbrücken

Trotz des hohen Entwicklungsstands der Holzverbundbrückentechnologie, fehlen ausreichende Entwurfsgrundlagen für die Berücksichtigung des Einflusses der Rissbildung auf die Schnittkraft- und Verformungsverteilung. Im Rahmen eines Forschungsprojekts an der Universidad Austral de Chile werden verschieden Aspekte der Rissbildung in Holzverbundbrücken mit Holzbalken mit größerer Höhe als Breite und elastischen stiftförmigen Verbindungsmitteln untersucht. Dabei wurde festgestellt, dass sich die Rissbildung auf den Schubmodul del Verbindungsmittel auswirkt. Dieser Einfluss wurde in Scherversuchen durch einen kleinen Spalt zwischen Holz und Beton simuliert. Anhand eines mit Versuchen kalibrierten FEM-Modells wurden eine Parameterstudie mit 120 verschieden Fälle durchgeführt. In den meisten Fällen tritt keine Rissbildung auf. Wenn es zu Rissbildung kommt, vergrössern sich die Holzzugspannungen und die Durchbiegung um bis zu 20 %. Wir stellen fest, dass Rissbildung auftritt, wenn das Bauhöhenverhältniss von Holz und Beton kleiner als die vierfache Kubikwurzel der mitwirkenden Plattenbreite der Betonplatte ist.

The Indian Concrete Journal, Jan 2009

Мостостроение мира 2'2008, 2008

ICTB2013–Las Vegas 2nd International Conference on Timber Bridges, Institute for Transportation at Iowa State University, 2013

ARCH'04, 4th International Conference on Arch Bridges, 2004, 2004

Wood Research, 2005

11o CONGRESO INTERNACIONALPROVIAL - Valdivia 2014 - Gestión y Patrimonio Vial, 2014

Volume 84, 1 February 2015, Pages 362–367, 2015

Behaviour of Steel Structures in Seismic Areas STESSA 2012, 2012

V Congreso de ACHE, 2011

XVII Jornadas Chilenas del Hormigón, 2009

Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In... more Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In the last five years there has been built a significant number of network arch bridges, maybe initiating a turning away from the traditional tied arches with vertical hangers. When introducing new structures it is important to understand well its structural behavior in order to assure the usual safety and quality level. In arches, the buckling behavior is of particular interest. The existent solution does not explain the in-plane buckling of network arches to a satisfying extent, limiting its application range to a special case. A general parametric study of the in-plane buckling leads to a concept, which allows considering the problem as a curved compression strut with radial elastic support. Then, a simple analytical formula is derived that predicts the critical buckling load and buckling mode for in-plane buckling of network arch bridges with an error of less than 5%.

Calculation of the critical in-plane buckling load of network arches., 2009

Calculation of the critical in-plane buckling load of network arches.

Stahlbau, 2009

Journal of Bridge Engineering, 2010

Bautechnik, 2015

Beitrag zur Berücksichtigung des Einflusses der Rissbildung im Beton in Holz-Beton-Verbundbrücken

IABSE Madrid Symposium: Engineering for Progress, Nature and People, 2014

In the frame of a contract between the Chilean National Highway Authority, APIA XXI IAC S.A. and ... more In the frame of a contract between the Chilean National Highway Authority, APIA XXI IAC S.A. and the Universidad Austral de Chile, all bridges of the Los Rios Region have been inspected for structural, functional and durability damages or deficiencies. The total number of bridges inspected is 600 and includes 95 composite bridges, 98 reinforced and prestressed concrete bridges, 238 timber bridges, 168 hybrid timber-steel bridges and 1 steel bridge. The overall service conditions of the bridges are relatively low, mainly due to non-conformity with today's standards. These defects often affect the traffic safety, which requires immediate repair actions. 88% of all bridges require inmediate or short-term repairs. Due to limited funding it is not possible to fulfil these demands at once. It is very important to implement a regular maintenance program in order to increase the level of service conditions.

IABSE Madrid Symposium, 2014

TCC bridges are a more durable alternative to the very high number of conventional timber bridges... more TCC bridges are a more durable alternative to the very high number of conventional timber bridges en Chile's road network. In a research project, numerical analyses and laboratory tests were conducted in order to obtain the influence of concrete cracking in TCC beams. The results from the FEM simulations and from the shear tests indicate that the influence of the concrete cracking is not limited to a stiffness reduction of the concrete slab, but it the stiffness of the shear connectors is reduced, too. No other parameter was found to significantly improve the correlation between simulations and real tests. Laboratory tests validate that small concrete cracks can cause significant connector stiffness reductions. Good correlations on the safe side between numeric simulation and test results is obtained, if the connectors' slip modulus is reduced by 60%, in addition to the theoretic concrete cracking.

ICTB2013–Las Vegas 2nd International Conference on Timber Bridges, 2013

Estética Propiedad deseable/imprescindible de un puente El valor estético, el aspecto visual, de ... more Estética
Propiedad deseable/imprescindible de un puente
El valor estético, el aspecto visual, de todos los puentes importa, ya que todos forman parte de nuestra vida
Los ingenieros diseñan los puentes, ellos deben encargarse del diseño estético
No existen recetas ni reglas para el diseño estético
El diseño es producto de un proceso creativo (se crea)
Hay que preguntares siempre a sí mismo: ¿Me gusta?

ARCH'04, 4th International Conference on Arch Bridges, 2004, 2004

Radial hanger arrangement for network arch bridges.

ARCH'04, 4th International Conference on Arch Bridges, 2004, 2004

Network arches have inclined hangers that cross each other at least twice. It seems to happen mor... more Network arches have inclined hangers that cross each other at least twice. It seems
to happen more often for railway bridges than for road bridges that structural elements above
the bridge deck are acceptable, which justifies investigations of the applicability of network
arches.
The tie can be a longitudinally prestressed concrete slab. This gives less noise, and the
additional self-weight favours the structural behaviour. Alternatives with steel and composite
bridge decks are discussed. For double track railway bridges spanning up to 100 metres the
arches can be rolled H-sections. For larger spans welded box sections are applicable.
For the design of network arches the hanger arrangement is important. Small bending
moments in the arches and small hanger forces are obtained when the upper hanger nodes
are placed equidistantly and all hangers cross the arch with the same angle. The cross
angle’s size depends on several parameters. Hints for a good choice are given. The maximum
hanger forces vary little, thus all hangers have the same cross-section.
To ensure passenger comfort and the stability and continuity of the track, deformations of
railway bridges are constricted. A network arch is a stiff structure with small deflections and
therefore suitable to comply with such demands even for high speed railway traffic.
A network arch railway bridge with a concrete tie usually saves more than half the steel
required for tied arches with vertical hangers and concrete ties.

11o CONGRESO INTERNACIONALPROVIAL - Valdivia 2014 - Gestión y Patrimonio Vial, 2014

Mesa Redonda “Reflexiones sobre el Terremoto del 27/02: De la Peligrosidad Sísmica a la Acción”, 2010

XXVI Congreso Chileno de Educación en Ingeniería, 2013

Behaviour of Steel Structures in Seismic Areas STESSA 2012, 2012

XV Congreso Nacional de Estudiantes de Ingeniería Civil, 2011

XVII Jornadas Chilenas del Hormigón, 2009

2009 World Steel Bridge Symposium, 2009

Bridges Latam 2011 - Chile Edition, 2011

Primer encuentro de exalumnos de Ingeniería Civil en Obras Civiles, 2014

In this work the results of investigations into how to optimise a network arch for the special d... more In this work the results of investigations into how to optimise a network arch for the special
demands of railway traffic are presented. Network arch bridges have inclined hangers that cross
each other at least twice. The beneficial structural behaviour leads to slender bridge members
mainly subjected to axial forces. Structural parts above the bridge deck are therefore more likely to
be tolerated. Furthermore, the high stiffness and therefore small deflections favour the application
of network arches for railway bridges. Stress ranges caused by the load character of railway
bridges require special considerations for the design. Adequate solutions are elaborated
considering as an example a double track railway bridge spanning 100 meters.
The arrangement of the hangers has considerable influence on the structural behaviour. It
decides on the forces and force variations within the network arch depending on many parameters,
as for example span, rise, number of hangers, loading or arch curvature. A new introduced type of
hanger arrangement is involved in an optimisation process with regard to the mentioned
parameters. This improved hanger arrangement provides a simple method of designing network
arches with small hanger forces and small bending moments in the chords.
The hanger connection details call for special attention to fatigue strains. The fatigue design
check is decisive for the hanger cross section. Various designs of hanger connection details for
circular hangers are tested by numeric analysis. A hanger connection detail is derived from the
results satisfying the special demands of slender arches as they are found in network arches.
The structural behaviour of a network arch favours a lower chord consisting of a concrete slab.
Its vertical deflections are limited to ensure passenger comfort and track stability. Alternatives with
and without transverse prestressing are compared considering the deformation behaviour and
economic differences. Several other construction details such as arch root point, bearings or
drainage are elaborated on and the solutions are presented. An erection method using a temporary
lower chord is assessed and described in detail.
The investigations confirm the suitability of network arches for railway bridges. Economic
advantages due to significant savings of steel compared to other arch bridges contribute to the
overall convincing performance.