In-plane and out-of plane experimental characterization of rc masonry infilled frames

Seismic investigations of typical south European masonry infilled frames were performed by testing two reduced scale specimens: one in the in-plane direction and another in the out-ofplane direction. Information about geometry and reinforcement scheme of those structures constructed in 1980s were obtained by [1]. The specimen to be tested in the in-plane direction was constructed as double leaf masonry while the specimen for testing in the out-of-plane direction is constructed with only its exterior leaf since the recent earthquakes have highlighted the vulnerability of the external leaf of the infills in out-of-plane direction [2]. The tests were performed by applying the pre-defined values of displacements in the in-plane and out-of-plane directions in the control points. For in-plane testing it was done by hydraulic actuator and for out-of-plane testing through the application of an airbag. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. Mid-point of the infill was assumed as a control point for outof- plane testing. Deformation and crack patterns of the infill confirm the formation of two-way arching mechanism of the masonry infill until collapse of the upper horizontal interface between infill and frame which is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam. This results in the crack opening through a welldefined path and the consequent collapse of the infill.

Seismic-resistant building practices resulting from local seismic culture

Considering that vernacular architecture may bear important lessons on hazard mitigation, this chapter focuses on the European Mediterranean countries and studies traditional seismic-resistant architectural elements and techniques that local populations developed to prevent or repair earthquake damage. This area was selected as a case study because, as a highly seismic region, it has suffered the effect of many earthquakes along the history and, thus, regions within this area are prone to have developed a Local Seismic Culture. After reviewing seismic resistant construction concepts, a wide range of traditional construction solutions that, in many cases, have shown to improve the seismic performance of vernacular constructions of these regions is presented, as a contribution to the general overview of retrofitting building systems provided in this book. The main motivation is that most of these techniques can be successfully applied to preserve and to retrofit surviving examples without prejudice for their identity.

Experimental assessment of an innovative strengthening material for brick masonry infills

The vulnerability of masonry infill walls has been highlighted in recent earthquakes in which severe inplane damage and out-of-plane collapse developed, justifying the investment in the proposal of strengthening solutions aiming to improve the seismic performance of these construction elements. Therefore, this work presents an innovative strengthening solution to be applied in masonry infill walls, in order to avoid brittle failure and thus minimize the material damage and human losses. The textilereinforced mortar technique (TRM) has been shown to improve the out-of-plane resistance of masonry and to enhance its ductility, and here an innovative reinforcing mesh composed of braided composite rods is proposed. The external part of the rod is composed of braided polyester whose structure is defined so that the bond adherence with mortar is optimized. The mechanical performance of the strengthening technique to improve the out-of-plane behaviour of brick masonry is assessed based on experimental bending tests. Additionally, a comparison of the mechanical behaviour of the proposed meshes with commercial meshes is provided. The idea is that the proposed meshes are efficient in avoiding brittle collapse and premature disintegration of brick masonry during seismic events.

Traditional timber frame walls: mechanical behavior analysis and retrofitting

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.

Local seismic cultures: the use of timber frame structures in the south of Portugal

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.

Reducing seismic vulnerablity: Retrofitting historic buildings

The value of preserving historic buildings is increasingly accepted by society, which not only recognizes built cultural heritage as a part of its identity but is also more cognizant of its economic value. In Europe, for example, tourism accounts for 10 percent of the GDP in the EU and 12 percent of employment.1 Built cultural heritage is a fundamental element of what draws tourists to European destinations. To a great extent, the value of historic buildings rests in the integrity of their components as unique products of the technology of their time and place. Unfortunately, cultural heritage buildings are particularly vulnerable to disasters, for a variety of reasons. They are often damaged or in a state of deterioration; they were built with materials with low resistance; they are heavy; and the connections among their various structural components are frequently insufficient. The main causes of damage are lack of maintenance, water-induced deterioration (from rain or rising damp), soil settlement, and extreme events such as earthquakes. Earthquakes have caused hundreds of thousands of deaths in the last decade, in addition to the tremendous losses in built cultural heritage.

Análise experimental do comportamento ao corte de paredes reforçadas em alvenaria de BTC

Dissertação de mestrado integrado em Engenharia Civil

Desenvolvimento de materiais auxéticos para aplicações estruturais

Dissertação de mestrado integrado em Engenharia Civil

Связь почвенного радона и электропроводности воздуха с землетрясениями

განხილულია საქართველოს პირობებში მიწისძვრების ეფექტი ნიადაგის რადონის შემცველობის და ჰაერის ელექტროგამტარობის ცვალებადობაში

Крупные оползнево-гравитационные явления, как подтверждающий феномен ареала возможного возникновения сильных землетрясений (на примере южного кавказа)

ნაშრომში წარმოდგენილია საქართველოს ტერიტორიაზე ცალკეული მონაკვეთებისათვის არსებული მასალების განზოგადებისა და საველე გეოლოგიურ-გემორფოლოგიური და სეისმოტექნიკური გამოკვლევების რეზულტატები. ამ გამოკვლევების შედეგად გამოვლენილ იქნა აქამდე უცნობი სრულიად ახალგაზრდა ტექტონიკური დეფორმაციული, როგორც ტერასულ დანალექ, ასევე ძირითად კლდოვან ქანებში და მათთან დაკავშირებული სეისმოგენური მეწყერულ-გრავიტაციული წარმონაქმნები.

Деформациоонная энергия земной коры, высвобождаемая при сильных землетрясениях

მიწისძვრის დროს გამოთავისუფლებული ენერგიის სიდიდე შეიძლება მიღებულ იქნეს დეფორმაციის კომპონენტების სიდიდეების გამოყენებით. მნიშვნელოვანი დეფორმოგრაფიული ჩანაწერები იქნქ მიღებული თბილისის მიმოქცევების მიწისქვეშა ლაბორატორიაში ფარავნის (13.5.1986) და სპიტაკის (1.12.1988) მიწისძვრებისათვის.

Остаточные наклоны поверхности Земли при некоторых близких землетрясениях

მნიშვნელოვანი დახრმზომითი ჩანაწერები იქნა მიღებული თბილისის მიწისქვეშა მიმოქცევით ლაბორატორიაში რამდენიმე ახალი ძლიერი მიწისძვრისათვის. შეფასებულ იქნა ნარჩენი დახრები, რომელთა შედარებით, რღვევის გარკვეულ თეორიულ მოდელთან საშუალება მოგვეცა გამოგვეთვალა რღვევის სიგრძე კერაში.

Остаточные смещения, деформации и наклоны поверхности земли, связанные с сильными землетрясениями

ძლიერი მიწისძვრებით გამოწვეული ნარჩენი გადაადგილებების, დეფორმაციების და დახრების გამოსათვლელად გამოყენებულია სტეკეტის, ჩინერის და მარუიამის მიერ შემოთავაზებული რღვევების დისლოკაციის თეორია.

Некоторые статистические результаты для выявления экзогенных факторов землетрясений Кавказа

ნაშრომში შესწავლილია პლანეტებისა და მათი წყვილების ცის თაღზე განაწილება კავკასიის ძლიერი მიწისძვრების მოხდენის მომენტში.

Sequencing lifeline repairs after an earthquake: an economic approach

Recoveries after recent earthquakes in the U.S. and Japan have shown that large welfare gains can be achieved by reshaping current emergency plans as incentive-compatible contracts. We apply tools from the mechanisms design literature to show ways to integrate economic incentives into the management of natural disasters and discuss issues related to the application to seismic event recovery. The focus is on restoring lifeline services such as the water, gas, transportation, and electric power networks. We put forward decisional procedures that an uninformed planner could employ to set repair priorities and help to coordinate lifeline firms in the post-earthquake reconstruction.