Different types of vertical elements, such as masonry, massive walls and timber frame elements, exhibit a different response exposed to the same loading scenario, in particular when it concerns dynamic loading. It is therefore paramount to investigate the principal response of different types of construction with different materials under a variety of loading scenarios. From there, the design of strengthening techniques against earthquakes can be performed. This paper presents the results from experiments, where various retrofitting techniques were tested. The goals were to define and improve laboratory procedures for evaluating the intervention technologies and specifications for laboratory specimens. From this base tests to characterise the experimental behaviour of original and strengthened masonry walls were performed, in order to obtain information on the system performance and the main constitutive laws relevant for modelling. The test campaigns were focused on static tests as well as cyclic tests of unreinforced and reinforced vertical building elements. The study is part of our work in the framework of the ongoing project NIKER funded by the European Commission dealing with improving immovable Cultural Heritage assets against the risk of earthquakes.
Traditional timber frame walls are an important structural element of many buildings and are usually composed of vertical posts and horizontal beams with bracing diagonal elements. In Portugal the timber frame walls, known as frontal walls, are usually part of Pombalino buildings, which were introduced by the Marquis of Pombal, who was responsible for the reconstruction of Downtown Lisbon after the great earthquake of 1755, which partially destroyed the city.
Given the increasing interest of the research community to this structural system, it is important to promote the discussion of the main findings that can contribute to the advance on the knowledge of the mechanical behaviour of timber frame buildings to seismic action.
Therefore, this paper intends: (1) to give an overview of the different solution of timber frame structures in different countries with special focus on the frontal walls characteristic of Pombalino buildings; (2) provide some examples of the reasonable behaviour of timber frame buildings in past earthquakes; (3) to summarize the experimental research carried out in the recent years in analysis of the behaviour to in-plane cyclic loading.
Half-timbered structures constitute an important cultural heritage of many countries, since they represent a typical anti-seismic construction adopted worldwide ; therefore, their preservation is of the utmost importance. Although recent earthquakes have pointed out the good seismic behaviour of this kind of structures, few experimental studies are available on the performance of traditional half-timbered walls and their retrofitting solutions and mainly only qualitative information is available of the seismic response of such structures. Due to this lack of information, an extensive experimental campaign was carried out, performing in-plane cyclic tests on real scale half-timbered and timber frame walls, adopting connections and dimensions encountered in real structures and considering different infill types (brick masonry and lath and plaster).
Moreover, keeping in mind the great rehabilitation effort that has been carried out in recent years on such buildings, such in the case of the Portuguese Pombalino buildings in Lisbon, it is important to study the effect of strengthening on traditional timber-frame walls. To do this, retrofitting solutions have been applied to traditional walls and tested under cyclic loading. Both traditional and innovative techniques have been considered...
Half-timbered buildings represent an important historical heritage in many countries. They are diffused in various regions for different reasons, such as availability of materials, to lighten a structure, low cost and the strength they offer, and as a construction element able to resist seismic actions. This latter issue is the research topic analysed here, as half-timbered buildings have been specifically used in reconstruction plans as earthquake-resistant buildings
in many countries, such as Portugal, India, Greece, etc. The aim of this paper is to study the behaviour under cyclic loading of such half-timbered walls, with typical connections, materials and geometries encountered in existing buildings.
Traditionally, different types of infill could be applied to half-timbered walls depending on the country, namely brick masonry, rubble masonry, hay, mud, etc. The focus of this paper is to study and compare the seismic behaviour of the walls considering two different infill typologies, as well as the possibility of having no infill, i.e. considering only the timber frame. Cyclic test were performed on traditional walls and their behaviour was studied in terms of ultimate capacity, deformability, energy dissipation and stiffness.; Fundação para a Ciência e a Tecnologia (FCT)
Tese de doutoramento
Engenharia Civil - Estruturas; Timber frame structures constitute an important cultural heritage of many countries, since
they represent a typical anti-seismic construction adopted worldwide. Therefore, the
preservation of these structures is of the utmost importance. Although recent earthquakes
have pointed out the good seismic behaviour of this kind of structures, few experimental
studies are available on the performance of traditional half-timbered walls and their
retrofitting solutions. Aiming at filling this research gap and at better understanding the
behaviour of these historic elements under seismic loads, an extensive experimental
campaign has been carried out, performing in-plane cyclic tests on real scale half-timbered
and timber frame walls, adopting connections and dimensions found in real structures and
considering different infill types (brick masonry and lath and plaster). Moreover, considering
possible damages caused by earthquakes, after the unreinforced tests, the walls were
retrofitted and re-tested to compare the efficiency of the retrofitting solutions in terms of
maximum load, ductility, cyclic stiffness, energy dissipation and equivalent viscous damping.
Both traditional and innovative retrofitting techniques were adopted...
Traditional timber frame walls are constructive elements representative of different timber frame
buildings that are well known as one of the most efficient seismic resistant structures in the world.
Timber frame walls were also used in the reconstruction of buildings of the old town of Lisbon after
the earthquake of 1755 aiming at improving their seismic global behaviour. As it is important to
preserve these structures, a better knowledge about their behaviour under seismic actions is
important and can give some indications about possible retrofitting techniques to be used to
improve the seismic performance. Due to the great rehabilitation effort currently carried out in
many countries, a better understanding of retrofitting techniques is also needed. Therefore, this
paper aims at providing a study on possible retrofitting techniques adopting traditional solutions
such as bolts and steel plates. Static cyclic tests have been performed on retrofitted traditional
timber frame walls in order to study their seismic performance. The experimental results showed
the overall good seismic performance of steel plates and the more ductile behaviour of retrofitted
timber frame walls with bolts.; Fundação para a Ciência e a Tecnologia (FCT)
This paper deals with a numerical study on the structural performance of masonry-to-timber connections in ancient buildings. The work is supported on an experimental campaign carried out at University of Minho, which aims at characterising a strengthening solution based on the use of injected anchors for the improvement of the connection between masonry and timber frame walls. The numerical study resorts to a detailed 3D finite element model, which reproduces the experimental test setup and proce- dure. The modelling approach adopted allows an accurate characterisation of the behaviour of all struc- tural elements, in terms of stress field and displacement distribution. The 3D model was validated against the available experimental results, which was then used to perform parametric analyses in order to eval- uate the influence of key parameters. Finally, simplified analytical approaches to estimate the strength capacity of injected anchors on masonry are presented and discussed.
Tabique construction corresponds to a relevant Portuguese heritage. Urban and rural tabique construction exists all over the country. This traditional building technique started to be in disuse after the massive introduction of the reinforced concrete. Therefore, tabique buildings are already aged and, in general, they show signals of degradation. Recent research works have concluded that this degradation stage is essentially caused by the absence of a regular proper maintenance process. The fact that tabique buildings are mainly private property, that there are economical limitations and that there is still a lack of knowledge concerning this traditional building technique, have been the main reasons identified. In order to contribute solving this problem this paper intends to give an input on the characterization of timber frame structural system of tabique walls. In fact, a tabique building element is a structural system formed by a timber frame coated with an earthy render. The elements of the timber frame are nailed to each other. It has been noticed that there are different types of timber frames. Given technical information related to these alternative traditional structural solutions may be helpful in future rehabilitation processes. At the same time...
The use of plastered straw bale walls in residential construction is growing as builders and owners seek environmentally friendly alternatives to typical timber construction practices. Straw has excellent insulation properties and is an agricultural bi-product which is annually renewable, and is often considered a waste product of grain production.
This thesis presents new models for predicting the compressive strength of plastered straw bale assemblies subjected to concentric and eccentric load. A constitutive model for lime-cement plaster is adapted from a stress-strain model for concrete, available in the literature. Twenty-two cylinder tests on plasters typically used for straw bale construction were used to verify the constitutive model.
The models for plastered straw bale assemblies were verified by testing plastered straw bale assemblies under concentric and eccentric compressive loads. An innovative steel frame test jig was designed to facilitate fabrication and testing of the specimens. Using this jig, 18 specimens of height 0.33 m, 0.99 m, 1.05 m or 2.31 m were subjected to concentric or eccentric compressive load until failure. The experimental strengths of the assemblies ranged from 23 kN/m to 61 kN/m, depending on the eccentricity of the load...
Timber frame buildings are well known as an efficient seismic resistant structure
and they are used worldwide. Moreover, they have been specifically adopted in codes and
regulations during the XVIII and XIX centuries in the Mediterranean area. These structures
generally consist of exterior masonry walls with timber elements embedded which tie the
walls together and internal walls which have a timber frame with masonry infill and act as
shearwalls. In order to preserve these structureswhich characterizemany cities in theworld it
is important to better understand their behaviour under seismic actions. Furthermore, historic
technologies could be used even in modern constructions to build seismic resistant buildings
using more natural materials with lesser costs. Generally, different types of infill could be
applied to timber frame walls depending on the country, among which brick masonry, rubble
masonry, hay and mud. The focus of this paper is to study the seismic behaviour of the walls
considering different types of infill, specifically: masonry infill, lath and plaster and timber
frame with no infill. Static cyclic tests have been performed on unreinforced timber frame
walls in order to study their seismic capacity in terms of strength...
Timber frame buildings are well known as an efficient seismic resistant structure popular all over the world not only due to their seismic performance, but also to their low cost and the strength they offer. These constructions still exist today and it is important to be able to preserve them, so a better knowledge on their behaviour is sought. Furthermore, historic technologies could be used even in modern constructions to build seismic resistant buildings using more natural materials with lesser costs.
A great rehabilitation effort is being carried out on this type of buildings, as their neglect has led to decay or their change in use and alterations to the structure has led to the need to retrofit such buildings; only recently studies on their behaviour have become available and only a few of them address the issue of possible strengthening techniques for this kind of walls.
In this scope, an innovative retrofitting technique (near surface mounted steel flat bars) is proposed and validated on traditional timber frame walls based on an extensive experimental program. The results of the static cyclic tests on distinct wall typologies retrofitted with the NSM technique are herein presented and discussed in detail. The main features on deformation...
Fonte: Universidade de CambridgePublicador: Universidade de Cambridge
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Drawing; similar to watercolour engraved by Cook J.W. as `P[un]t[a] Arena[s] -- San Carlos, Chilo? ?? reproduced facing Narrative 1: 300. "About 1840 the Governor of Chile established a penal colony at Punta Arenas and Port Famine, which miserably failed in consequence of a mutiny." Narrative "P 300. Vol 1 --" [top centre]; "RF" FitzRoy [top right corner]; The main feature, standing in the left and left centre of the picture, is a timber frame thatched single storey building, with six somewhat irregularly spaced wooden uprights, a small barred window between the third and fourth uprights from the left, and a veranda at the right end. The thatched roof is `anvil'-shaped, i.e., the lower part pitched inwards and the upper part back outwards. The walls appear to be of horizontal timber boarding. In the foreground there are two treestumps, the left-hand one below the window, sawn off, the right-hand one closer to the viewer, leaning and broken, with new foliage beginning to sprout. To the left of both stumps there are tall tufts of grass. To the right of the building, two human figures stand close to the veranda, at the upper end of ground which slopes downwards from the centre to the right centre of the picture to lower rough level ground in the right of the picture...
The acoustic and aesthetic design of a ceremonial dinner gong for the fiftieth anniversary of University House at the Australian National University is described. The gong is made from polished stainless steel with a walnut frame constructed from the same timber used in building the Great Hall, and the shape of the frame echoes the slightly sloping walls of the Hall in which it will be housed and used.
Timber frames are commonly adopted as a structural element in many countries with specific
characteristics varying locally, in termsof geometry and materials.Their diffusion in Southern European countries
is linked to their good seismic-resistant capacity, but only in the last decade interest has grown for this structural
typology, and studies have been performed to better understand their behaviour. In this contribution, a brief
state of the art on existing timber frame building typologies is presented, focusing on their seismic-resistant
characteristics. Additionally, an overview of possible strengthening solutions, adopted both in practice, and
tested experimentally are presented. Their performance when applied to walls and connections is also discussed.
Timber frame construction is characteristic of several historic city centres as well as of vernacular architecture in several countries around the world, either motivated by the availability of materials and construction traditions or by the need of reducing the seismic vulnerability of buildings, namely in south European countries, where this construction technique was adopted for seismic-resistance purposes. From past earthquakes, it has been seen that timber frame construction can be viewed as an interesting technology as it has exhibited a very reasonable behaviour when compared to other traditional construction techniques such as masonry walls.
This chapter provides an overview of the main insights on the seismic performance of timber frame buildings from the evidences of past earthquakes and provides the main results of recent research focused on the in-plane cyclic behavior of timber frame walls with distinct geometrical configurations. Additionally, the main seismic performance indexes of timber frame walls, both unreinforced and retrofitted, are presented and discussed in detail.
Given the fact that using timber frame structures has proven to improve the seismic behavior of
vernacular architecture, as has been reported in past earthquakes in many countries, its
preservation as a traditional earthquake resistant practice is important. This paper firstly intends
to evaluate whether the use of timber frames as a traditional seismic resistant technique for
vernacular architecture in the South of Portugal, traditionally a seismic region, is still active.
Secondly, the city of Vila Real de Santo António was selected as a case study because it also
followed a Pombaline development contemporary to the reconstruction of Lisbon. The plan
included the provision of timber frame partition walls for some of the buildings and, thus, an
overview of the type of constructions originally conceived is provided. Finally, the alterations
done in the original constructions and the current state of the city center are described and the
effect of these changes on the seismic vulnerability of the city is discussed.