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Grout injection is a widely used technique for consolidation of multi-leaves masonries, aimed at increasing the compactness and to create links between the internal and external leaves that will improve shear, flexural and compressive resistances. Grouts can be seen as mixtures of binder with water, admixtures and/or additives, which should present low viscosity and high penetrability. The definition of a grout composition should involve the knowledge of the injection capacity within a specific type of masonry and good physical and chemical compatibility with the original materials present in the historic structures. The flow of the grout through the masonry depends on the fresh grout properties, such as stability, water retention and rheological behaviour. Thus, the evaluation of the performance of the grout as function of a porous medium is firstly started by checking the intrinsic properties of the grout (namely rheological and stability) and then by controlling the injectability of masonry by injection tests on cylinders. Since it is difficult to reproduce a real masonry and to visualize what is happening inside the porous medium being injected, masonry samples were created by filling plexiglass cylinders with a fraction of limestone sands and crushed brick. These materials are sieved to obtain different grain size distributions to enable the simulation of different permeabilities and internal structures for the masonry. The lack of information about the performance of hydraulic lime based grouts as a function of the properties of the porous medium to be injected enhances the need of a detailed research on the subject.

Grouting is a current repair technique for consolidating and strengthening old masonry buildings. Grouts can be seen as mixtures of binder with water, admixtures and/or additives, which should present low viscosity and high penetrability. The grout specification involves the knowledge of the flow capacity within the masonry inner core and physic-chemical compatibility with the original materials. Nevertheless, the grout properties are affected by a large number of parameters, including binder type and composition, mixing procedure, type and dosage of admixture, environmental conditions such as temperature that may lead to different grout injection capacities, as reported by several authors. This paper deals with the effect of environmental temperature over superplasticized hydraulic lime-based grouts with partial replacement of lime by silica fume. Grout performance was analysed in fresh and hardened state by testing its rheological behaviour, injectability as well as its hydration reactions kinetics. In spite of the considerable amount of information that exists for cement based mixtures with superplasticizers, there is little information about the effects of superplasticizers when used in natural hydraulic lime mixtures proportioned with silica fume. This study aims to contribute to a better understanding of the behaviour that superplasticized hydraulic lime grouts present under different temperatures. The results showed that hydraulic lime grouts performance could be improved, regarding rheological parameters and strength capacity if they are properly design and a suitable processing temperature were ensured.

In a recent paper (Goncalves and Camotim, 2013 [1] ), the authors presented an investigation concerning the buckling (bifurcation) behaviour of uniformly compressed thin-walled tubes with regular polygonal cross-sections (RCPS). The present paper complements the previous work by addressing the local and distortional buckling behaviour of RCPS members subjected to bending or torsion and aims at providing a novel insight into these phenomena. In particular, the specialization of Generalized Beam Theory (GBT) for RCPS, as recently proposed in Goncalves and Camotim (2013) [2] , is employed to obtain closed-form analytical solutions and also to carry out parametric studies by means of numerical analyses which are both computationally efficient (due to the small number of d.o.f. involved) and clarifying (due to the modal decomposition features of GBT). For validation purposes, solutions taken from the literature and also standard shell finite element model results are employed.

This paper presents and discusses the results of a GBT-based numerical investigation concerning the local, distortional and global buckling behaviour of lipped channel and zed-section cold-formed steel purlins restrained by steel sheeting and subjected to an uplift loading. Strengthened (lapped) joints, commonly employed at internal supports to preclude the occurrence of local/distortional buckling phenomena, are also investigated and an illustrative application of the use of GBT to determine strengthening lengths is also presented. The sheeting restraint is modelled by means of elastic translational and rotational springs, located at the purlin upper flange, and the joint strengthening is modelled by doubling the cross-section wall thickness. For validation, the GBT-based results are compared with values yielded by A nsys shell finite element analyses.

Unstabilised rammed earth is a recyclable, economical and eco-friendly building material, used in the past and still applied today. Traditionally, its use was based on a long empirical knowledge of the local materials. Because this knowledge was mostly lost or is no longer sufficient, in many countries normative documents have been produced to allow the assessment of rammed earth soils. With the aim of contributing for a refining of these normative requirements, this article presents a research work that included: (i) collection of unstabilised rammed earth samples from six constructions in Portugal; (ii) a literature survey of normative and complementary documents to identify the most mentioned key-properties, the test procedures and the corresponding threshold limits; (iii) a discussion of the test procedures and of the thresholds limits in the light of the experimental results. The analyzed properties are the particle size distribution, maximum particle size, plasticity, compaction, linear shrinkage, organic content and salt content. The work highlights the advantages of taking into account the characteristics of existing constructions as a basis for the establishment and further refining of consistent threshold values. In particular, it shows that it is essential to adjust the requirements to the specificities of local materials. This work was carried out at the National Laboratory for Civil Engineering (LNEC), in Lisbon. M. I. Gomes was supported by a doctoral grant from the Portuguese Foundation for Science and Technology (FCT). 7 12 25p We are grateful to many people from the Geotechnics and the Materials Departments of LNEC who collaborated in the experimental work. We would like to thank, in particular, José Costa, João Júnior and João Ribeiro. We are also thankful to the owners of all buildings that allowed the collection of material. To Raul Almeida and the architects Ines Fonseca and Florbela Vitorino who helped in the search of suitable buildings in Odemira, Avis and Arraiolos. DOI:10.1080/15583058.2012.683133M DM/NPC International Journal of Architectural Heritage

This paper deals with the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer. Preliminary tests were conducted to focus on the grout best able to fill a fibrous network since the goal of this study was to develop an optimized grout able to be injected in a mat of steel fibers for concrete strengthening. The grout composition was developed based on criteria for fresh state and hardened state properties. For a CEMI 42.5R based grout different high range water reducer dosages (0%, 0.2%, 0.4%, 0.5%, 0.7%) and silica fume (SF) dosages (0%, 2%, 4%) were tested (as replacement of cement by mass). Rheological measurements were used to investigate the effect of polycarboxylates (PCEs) and SF dosage on grout properties, particularly its workability loss, as the mix was to be injected in a matrix of steel fibers for concrete jacketing. The workability behaviour was characterized by the rheological parameters yield stress and plastic viscosity (for different grout temperatures and resting times), as well as the procedures of mini slump cone and funnel flow time. Then, further development focused only on the best grout compositions. The cement substitution by 2% of SF exhibited the best overall behaviour and was considered as the most promising compared to the others compositions tested. Concerning the fresh state analysis, a significant workability loss was detected if grout temperature increased above 35 °C. Below this temperature the grout presented a self-levelling behaviour and a life time equal to 45 min. In the hardened state, silica fumes increased not only the grout’s porosity but also the grout’s compressive strength at later ages, since the pozzolanic contribution to the compressive strength does not occur until 28 d and beyond.

The injection of grouts inside multi-leaf stone masonries is a technique widely used for structural consolidation. To ensure an adequate flow of the grout inside the masonry, it is crucial to assure good fresh grout properties, such as good rheological behaviour. The scope of this paper is to provide preliminary indications and valuable data about the effects of specific hydraulic lime grout composition on their rheological behaviour with the purpose of a successful injection process. Through the use of rotational rheometer together with the Taguchi method, it was possible to study the influence of water/binder ratio, the type and dosage of superplasticizer and the partial replacement of hydraulic lime by silica fume, upon the grout rheological properties. The study leads to the conclusion that polycarboxylate-based superplasticizers present better performance from a rheological point of view than the naphthalene-based superplasticizer and that the water/binder ratio and superplasticizer dosage are the most determinant factors in the fresh grout rheological behaviour. On the other hand, silica fume dosage turned out to be the factor with the least contribution to improve the grout rheological behaviour compared to the other two factors reported in this study. The results summarised in this paper are part of a larger study and precede the analysis of the performance of those grouts when injected into different porous media that simulate old masonries.

The present work reports the experimental research carried out to study a strengthening method for flat slabs under punching by introduction of new shear reinforcement. Eight specimens were strengthened with the introduction of prestressed vertical bolts, using different anchorage approaches: large anchorage on surface, small anchorage on surface and small embedded anchorage. A reference specimen, unstrengthened, was also tested. The experimental punching loads, failure modes and shear reinforcement contribution are compared with the provisions of EC2, ACI 318-11 and MC2010. The tests results show that using small embedded anchorage plates is viable and efficient method for punching capacity improvement. Additionally is a method also with advantages of better aesthetics for the final strengthened structure.

One of the techniques of old masonry consolidation is the injection of grouts. For a successful injection it is necessary to ensure an adequate flow of the grout inside the porous media, for which it becomes essential to control the grout rheological behaviour and stability. This paper analyses the influence of grout mixing procedures on rheological behaviour, water retention and stability of hydraulic lime grouts with superplasticizer. This research has particular relevance due to lack of information about the use of superplasticizers in hydraulic lime grouts, compared to the amount of information that exists in the case of Portland cement based mixtures. The research showed that fresh grout behaviour can be improved using an appropriate mixing procedure, optimised with the Taguchi method.

This work presents an experimental study concerning the post-punching behaviour of flat slabs strengthened with a new technique based on post-tensioning with anchorages by bonding using an epoxy adhesive. This strengthening technique proved efficient with respect to ultimate and serviceability states. Five slab specimens were tested in the post-punching range and it was found that the post-punching resistance was on average 78% of the punching resistance. This paper reports the development of strand forces and slab displacements from the beginning of the tests, including the bond stresses developed at several stages of the loading process. It was observed that top reinforcement bars were capable of transmitting post-punching loads to the prestressing strands. Taking this into account and based on the load bath envisaged from the column to the slab, expressions for the vertical load capacities corresponding to the parts of the load path are presented and compared with the experimental results, showing their ability to predict both ultimate loads and modes of failure. Compared with other strengthening techniques, the one proposed here not only upgrades ultimate and serviceability behaviour but also adds post-punching resistance, which is a great advantage in the event of progressive collapse, since it may avoid the collapse of an entire structure, thus reducing the risk of material and human losses.

This work aims to study a new flat slab strengthening technique based on post-tensioning with anchorages by bonding using an epoxy adhesive. The main advantages of this technique over the traditional prestress strengthening systems that use mechanical anchorages are that it does not need external permanent anchorages, meaning that the forces are introduced into the concrete gradually instead of being localized, thereby preserving aesthetics and useable space. The seven tested slab models show that this technique meets its objective as it is able to reduce reinforcement strains at service loads by up to 80% if the strengthening technique is applied in two directions and slab deformations by up to 70%, consequently making crack widths smaller. It can also increase punching load capacity by as much as 51% when compared to non-strengthened slabs. The results are compared with the EC2 (2004) [20], ACI 318-08 (2008) [23] and MC2010 (2010) [21] provisions. The main conclusions are that this strengthening technique is effective regarding ultimate and serviceability states and that it represents an advance in RC slab strengthening techniques.

This work presents a procedure for the use of probabilistic modelling techniques in the assessment of safety parameters of existing timber structures, when influenced by two types of actions. The parameters of the models have been defined as probabilistic variables, and Monte Carlo simulation technique was taken into account for safety evaluation. The case study here examined concerns four king post trusses on which a safety evaluation method was conducted to determine a target reliability index. Since the structures presented a high level of deterioration, a model considering the variation of the residual cross-section and the influence of environment in resistance was taken into account. Time dependent deterioration models have also been considered. With the results given by the different used models, it was possible to obtain probabilities of failure and respective reliability indices, as well as time evolution deterioration curves for a deteriorated historical structure.

The purpose of grout injection is to increase the compactness of the masonry and its injection optimization is a task of major importance for masonry consolidation. Fresh grout properties seem to be as important as the ones in the hardened state since grout consistency is an essential characteristic to allow the filling of voids. Since the grout rheological behaviour is associated with its fresh properties, they should be well understood and controlled so that the fluid may be pumped and flow correctly inside the porous media. This paper analyses some relevant rheological properties for natural hydraulic lime grouts, such as yield stress, plastic viscosity, consistency and power-law index. The study envisage to increase the understanding of the influence of environmental temperature and of the addition of fly ash in fresh grouts behaviour. An attempt was made to achieve an optimal grout composition by using the Taguchi method. The paper shows that fly ash is capable of substantially changing the grout rheological parameters, while the effect of temperature is negligible for the parameters tested.

This paper analyses and compares the dynamic behavior of superelastic shape memory alloy (SMA) systems based on two different constitutive models. The first model, although being able to describe the response of the material to complex uniaxial loading histories, is temperature and rate independent. The second model couples the mechanical and kinetic laws of the material with a balance equation considering the thermal effects. After numerical validation and calibration, the behavior of these two models is tested in single degree of freedom dynamic systems, with SMAs acting as restoring elements. Different dynamic loads are considered, including artificially generated seismic actions, in a numerical model of a railway viaduct. Finally, it is shown that, in spite of its simplicity, the temperature- and rate-independent model produces a set of very satisfying results. This, together with its robustness and straightforward computational implementation, yields a very appealing numerical tool to simulate superelastic passive control applications.

The transient dynamic response of a beam supported on a foundation with sudden stiffness change and subjected to a force moving with constant velocity is analysed. The abrupt change is located at the mid-section of the beam of finite length. Two analytical approaches are implemented. In the first one, the response is obtained by finite integral transformations incorporating global modes of vibration, while in the second the analytical responses of each half of the beam are linked by continuity conditions. The values obtained are used to study the influence of the abrupt change on the critical velocities. The analyses carried out enable to reach results and draw conclusions directly related to the knowledge of ground vibrations induced by high-speed trains.

This paper presents the derivation, validation and illustration of a generalised beam theory (GBT) formulation intended to perform first-order and buckling analyses of arbitrary thin-walled members, namely members with cross-sections that combine closed cells with open branches. Following a brief overview of the so-called “conventional GBT formulation”, as well as of the available extensions for different specific cross-section types, the paper addresses in detail the modifications that must be incorporated into the GBT cross-section analysis procedure to handle the simultaneous presence of closed cells and open branches. The proposed formulation is then employed to analyse the first-order and buckling behaviours of thin-walled members (mostly beams) with complex cross-sections. For validation purposes, the GBT-based numerical results are compared with values yielded by shell finite element and finite strip analyses.

The purpose of a grout injection technique applied in a multiple leaf wall is to increase the compactness and create links between the internal and external leaves. The correct grout selection should take into account many characteristics, in particular injectability and stability. This paper analyses the variations of some fresh grout properties that may affect injectability and stability—water retention, rheological behaviour and bleeding. The study has sought to increase the understanding of the influence of the mixing procedure in grout behaviour and how it may improve some essential injection characteristics. For this purpose, a natural hydraulic lime grout has been considered. The paper shows that there are differences in the grout behaviour when different mixing procedures are used and that fresh grout properties may be optimized if a proper mixing procedure is chosen.

International bibliography on conservation usually refers that mortars made with lime putty with long extinction periods behave better than others made with the current dry hydrated limes. In order to evaluate this assess, an experimental study of lime mortars was carried out, using dry hydrated lime and two lime putties. It becomes clear that the use of lime putties with long extinction periods in mortars allow better performances, particularly in applicability and resistance to sulphates.

The progressive collapse of structures generally results in the loss of human lives. Experience shows that flat slab structures are very sensitive to progressive collapse, which may cause serious accidents if special detailing is not provided. The post-punching behaviour of a column-supported slab is decisive in the progressive collapse development. This work presents the experimental research carried out to study the post-punching behaviour of prestressed concrete flat slabs. Six reduced-scale prestressed concrete flat slab models were tested. The tests were carried out in two different phases. In the first phase the models were loaded up to failure by punching. Afterwards, the models were loaded again to study the post-punching behaviour changes caused by the presence of unbonded, prestressed tendons and the influences of their distance to the column.

Structural design relies essentially on tests made on cylinders of small size to estimate the probability of failure of prototype members, since full-scale testing of structures to determine their strength is not feasible. The confidence that such scale modeling deserves in terms of representation of actual behavior needs careful examination, due to such factors as material nonlinearities, difficulties of scale representation of particulate materials, and sometimes the impossibility of simultaneously satisfying independent dimensionless parameters. Some failures explained by linear fracture mechanics are associable with strong size effects, as opposed to the cases where small cracks are a material property. Besides research centered on these problems, a number of studies of scale effects have been associated with the increased probability of finding a flaw in larger objects. In fact, geometric similitude may coexist with microscopic randomness of flaws that cause size effects to appear. The type of materi...

The main objective of a bridge manager is to find the best maintenance plan for a group of bridges over a prescribed time horizon. The bridge manager usually faces conflicting ob- jectives, as nlaintenance plans resulting in safer and less deteriorated structures also lead to higher costs. In general, the problem is posed as a deterministic single-objective optimiza- tion where cost is minimized keeping performance above pre-defined thresholds. However, single-objective optimization results in only one optimal solution that does not provide the advantages or disadvantages of considering other objectives and constraints. In addition, the effects of uncertainties are not taken into account or are included in a very simplified way. The bridge manager obtains, in this way, only one deterministic optimum maintenance plan, and not a set of different probabilistic maintenance solutions from which the best, for each particular situation, can be chosen. In this paper, a full probabilistic multi-objective approach to bridge maintenance con- sidering single maintenance types is developed. This approach is based on the latest de- velopments in bridge management by considering probabilistic continuous performance in- dicators and probabilistically defined objectives and constraints. The problem is solved by using multi-ob jective genetic algorithms and Latin hypercube sampling technique. Multi- objective applications to existing reinforced concrete bridge components under probabilistic deterioration and probabilistic-defined single maintenance types are presented and discussed., United States National Science Foundation - Grant Nos. CMS-0217290; CMS-0509772., United Kingdom Highways Agency., Netherlands Ministry of Transport, Public Works, and Wtaer Management.

The vertical stability of anchored concrete soldier-pile walls is highly influenced by the complexity of the interaction between the different parts of the structure, i.e., wall, anchors, and supported soil mass. The problem is analyzed using upper bound limit analysis through published solutions and proposed closed-form equations. A comparison is made between these equations and numerical limit analyses. An estimate of the theoretical minimum pile resistance required to avoid excavation collapse is presented. Published finite element elastoplastic results are used for comparison.Key words: anchored retaining wall, concrete soldier-pile walls, vertical equilibrium, finite elements, limit analysis, soil-to-wall interface shear forces.

This work deals with the incorporation of equivalent member imperfections in the global analysis of steel frames and, in particular, is intended to clarify the Eurocode 3 (EC3) provisions involved in such procedure. In fact, these provisions stem from the well-known “European column buckling curves”, which means that they are based on the behaviour of simply supported isolated members under uniform compression (columns). First, one addresses the geometrically non-linear behaviour of isolated columns displaying arbitrary support conditions and different initial geometrical configurations. Then, the results obtained are used to propose a systematic and rational method to evaluate the appropriate “equivalent initial imperfections” that need to be incorporated in the second-order global elastic analysis of a frame or isolated compressed member. This method (i) is fully consistent with the EC3 column buckling curves and (ii) adopts critical buckling mode shape initial imperfections with amplitudes determined by means of closed-form analytical expressions. In order to enable a better grasp of the concepts involved and also to illustrate the capabilities of the proposed methodology, several numerical examples are presented and discussed throughout the paper.

After an enormous investment in construction of highway networks undertaken in the second half of the 20th century, the highway networks of most European and North American countries are now completed or close to completion. As a result, the need in funding changed from building new highway structures to repair, rehabilitation, and replacement the existing ones. In this paper, a model for analyzing the evolution in time of probabilistic performance indicators of existing structures, in terms of condition, safety, and cost under no maintenance, preventive maintenance, and essential maintenance, is presented. This model integrates the current practice in bridge management systems based on visual inspections (condition index) with structural assessment (safety index) during the lifetime of existing structures. The proposed model allows the consideration of uncertainties in the performance deterioration process, times of application of maintenance actions, and in the effects of maintenance actions on the condition, safety, and life-cycle cost of structures by defining all parameters involved in the model as random variables. Interaction between condition and safety profiles is defined through probabilistic and deterministic relations. The probabilistic characteristics of the condition, safety, and cost profiles of deteriorating structures are computed by Monte-Carlo simulation. Several realistic examples, based on data on highway bridge components gathered in the United Kingdom, are presented.

Gravity loads can affect a reinforced concrete structure’s response to seismic actions, however, traditional procedures for testing the beam behaviour do not take this effect into consideration. An experimental campaign was carried out in order to assess the influence of the gravity load on RC beam connection to the column subjected to cyclic loading. The experiments included the imposition of a conventional quasi-static test protocol based on the imposition of a reverse cyclic displacement history and of an alternative cyclic test procedure starting from the gravity load effects. The test results are presented, compared and analysed in this paper. The imposition of a cyclic test procedure that included the gravity loads effects on the RC beam ends reproduces the demands on the beams’ critical zones more realistically than the traditional procedure. The consideration of the vertical load effects in the test procedure led to an accumulation of negative (hogging) deformation. This phenomenon is sustained with the behaviour of a portal frame system under cyclic loads subject to a significant level of the vertical load, leading to the formation of unidirectional plastic hinges. In addition, the hysteretic behaviour of the RC beam ends tested was simulated numerically using the nonlinear structural analysis software – OpenSees. The beam–column model simulates the global element behaviour very well, as there is a reasonable approximation to the hysteretic loops obtained experimentally.

An analytical description of the behaviour of a connection has to cover all sources of deformabilities, local yielding, local instabilities, etc. Due to the multitude of influencing parameters, a macroscopic inspection of a complex connection — by subdividing it into components — has proved to be most appropriate. This is the approach recently proposed by the Eurocode 3. One of the basic components is the equivalent T-stub, which adequately models several parts of a connection: column flange in bending, end plate in bending and flange cleat in bending. Reliability techniques combined with non-linear analysis of structures have been applied to interpret the effects of parameter variability on the T-stub behaviour. Simplified safety rules are derived from this probabilistic high-level approach.

Grouting is currently a repair technique for consolidating and strengthening old masonry structures. Grouts can be seen as mixtures of binder with water, admixtures and/or additives, which should present low viscosity and high penetrability. The grout specification involves the knowledge of the flow capacity within the masonry inner core and physic-chemical compatibility with the original materials present in the historic structures. Nevertheless, the grout properties are affected by a large number of parameters, including binder type and composition, mixing procedure, admixture type and dosage, environmental conditions, like temperature that may lead to different grout injection capacities, as reported by other studies. This paper deals with the effect of environmental temperature over superplasticised hydraulic lime-based grouts with partial replacement of lime by silica fume. Grout performance was analysed in fresh and hardened state by testing its rheological and mechanical behaviour, as well as its hydration reactions kinetics. In spite of the considerable amount of information that exists for cement based mixtures with superplasticisers, there is little information about the effects of superplasticisers when used in natural hydraulic lime mixtures proportioned with silica fume. This study aims to contribute to better understand the behaviour that superplasticised hydraulic lime grouts present under different temperatures. The results showed that hydraulic lime grouts performance could be improved, regarding rheological parameters and strength capacity if they are properly design and a suitable processing temperature were ensured.

The aim of this work is to provide new contributions in order to define more accurately the structural robustness concept, particularly when it is applied to corroded reinforced concrete (RC) structures. To fulfill such task, several robustness indicators are analyzed and discussed with special emphasis given to the structural performance based measures. A new robustness definition and a framework to assess it are then proposed, based on the structural performance lost after damage occurrence. The competence of the proposed methodology is then tested comparing the robustness of two reinforced concrete foot bridges under corrosion. Damage considered is the longitudinal reinforcement corrosion level and load carrying capacity is the structural performance evaluated. In order to analyze corrosion effects, a finite element based two step analysis is adopted. On the first step a cross section analysis is performed to capture phenomenons such as: expansion of the reinforcement due to the corrosion products accumulation; damage and cracking in the reinforcement surrounding concrete; steel-concrete bond strength degradation; and effective reinforcement area reduction. The results obtained are then used to built a 2D structural model, in order to assess the maximum load carrying capacity of the corroded structure. For each foot bridge, robustness is finally assessed using the proposed methodology. Fil: Cavaco, Eduardo. Universidade Nova de Lisboa; Portugal Fil: Casas, Joan R.. Universidad Politecnica de Catalunya; España Fil: Neves, Luis A. C.. Universidade Nova de Lisboa; Portugal Fil: Huespe, Alfredo Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico. Centro de Investigación de Métodos Computacionales; Argentina

Major similarities between robustness assessment and seismic design exist, and significant information can be brought from seismic design to robustness design. As will be discussed, although some methods and limitations considered in seismic design can improve robustness, the capacity of the structure to sustain limited damage without disproportionate effects is significantly more complex. In fact, seismic design can either improve or reduce the resistance of structures to unforeseeable events, depending on the structural type, triggering event, structural material, among others. Based on a case study, the influence of redundancy and ductility on the seismic behavior and robustness of a long-span timber structure is assessed., COST E 55

The goal of this research was to develop a methodology for grout composition optimization concerning specific applications. It could be developed for masonry consolidation or bonded prestressed tendon grout, pre-placed aggregate grout, among others. The grout development does not only depend on its intrinsic properties but also on the nature and features of the support. The purpose of a grout injection technique applied in a multiple leaf wall is to increase the compactness and create links between the internal and external leaves, which improve not only shear and flexural resistance but also the compressive strength. In practice, the variability of voids within masonries requires an ability to fine tune the rheological properties of the grout in order to optimally fill the voids. The methodology proposed here for testing grout injectability in a porous media like masonry is a logical tool to use in grout optimization. It shows that several grout parameters should be controlled for a successful injection. Concerning the support and its typology, the mortar between stones plays a fundamental role in the effectiveness of the intervention, due to its reduced porosity and composition. Besides that, earth and mortar, for example, can be present in the interior of masonry and make difficult, with their absorption, the injection. Thus, the water retention capacity of grout should be controlled to prevent that problem, as it was made in this work, using the optimized mixing procedure that takes into account that and other fresh grout properties. This study analyses some relevant grout properties such as yield stress, plastic viscosity, flowability and injectability for natural hydraulic lime based grouts in different porous media. The research shows that there are differences in the grout behaviour, especially in rheological properties, when different mixing procedures and/or grout composition (different water/binder or fly ash/binder ratios) are used and that fresh grout properties may be optimized for injection purpose.

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This paper provides an overview of the Generalised Beam Theory (GBT) fundamentals and reports on the novel formulations and applications recently developed at the TU Lisbon: the use of conventional GBT to derive analytical distortional buckling formulae and extensions to cover (i) the buckling behaviour of members with (i1) branched, closed and closed/branched cross-sections and (i2) made of orthotropic and elastic-plastic materials, and (ii) the vibration and post-buckling behaviours of elastic isotropic/orthotropic members. In order to illustrate the usefulness and potential of the new GBT formulations, a few numerical results are presented and briefly discussed. Finally, some (near) future developments are briefly mentioned.

Superelasticity, a unique property of shape memory alloys (SMAs), allows the material to recover after withstanding large deformations. This recovery takes place without any residual strains, while dissipating a considerable amount of energy. This property makes SMAs particularly suitable for applications in vibration control devices. Numerical models, calibrated with experimental laboratory tests from the literature, are used to investigate the dynamic response of three vibration control devices, built up of austenitic superelastic wires. The energy dissipation and re-centering capabilities, important features of these devices, are clearly illustrated by the numerical tests. Their sensitivity to ambient temperature and strain rate is also addressed. Finally, one of these devices is tested as a seismic passive vibration control system in a simplified numerical model of a railway viaduct, subjected to different ground accelerations.