Assessment of the efficiency of prefabricated hybrid composite plates (HCPs) for retrofitting of damaged interior RC beam–column joints

The effectiveness of prefabricated hybrid composite plates (HCPs) as a seismic retrofitting solution for damaged interior RC beam-column joints is experimentally studied. HCP is composed of a thin plate made of strain hardening cementitious composite (SHCC) reinforced with CFRP sheets/laminates. Two full-scale severely damaged interior beam-column joints are retrofitted using two different configurations of HCPs. The effectiveness of these retrofitting solutions mainly in terms of hysteretic response, dissipated energy, degradation of secant stiffness, displacement ductility and failure modes are compared to their virgin states. According to these criteria, both solutions resulted in superior responses regarding the ones registered in their virgin states.

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.

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.

Urban retrofitting: identifying disruptive and sustaining technologies using performative and foresight techniques

Cities, which are now inhabited by a majority of the world's population, are not only an important source of global environmental and resource depletion problems, but can also act as important centres of technological innovation and social learning in the continuing quest for a low carbon future. Planning and managing large-scale transitions in cities to deal with these pressures require an understanding of urban retrofitting at city scale. In this context performative techniques (such as backcasting and roadmapping) can provide valuable tools for helping cities develop a strategic view of the future. However, it is also important to identify ‘disruptive’ and ‘sustaining’ technologies which may contribute to city-based sustainability transitions. This paper presents research findings from the EPSRC Retrofit 2050 project, and explores the relationship between technology roadmaps and transition theory literature, highlighting the research gaps at urban/city level. The paper develops a research methodology to describe the development of three guiding visions for city-regional retrofit futures, and identifies key sustaining and disruptive technologies at city scale within these visions using foresight (horizon scanning) techniques. The implications of the research for city-based transition studies and related methodologies are discussed.

Galeata(FC). Rigenerazione urbana e recupero architettonico di plesso scolastico con retrofitting

Questa tesi si pone come obiettivo la riqualificazione architettonica del plesso scolastico del Comune di Galeata, cittadina della media valle del Bidente conosciuta sia per gli estesi ritrovamenti archeologici dell’antica città romana di Mevaniola e del cosiddetto “Palazzo di Teodorico”, sia per essere la città con la percentuale più alta di immigrati regolari a livello nazionale. Sono proprio queste peculiarità a guidare il progetto verso un intervento mirato non solo alla rigenerazione urbana dell’area ma anche civica e sociale attraverso la dotazione di nuovi servizi e spazi pubblici. Il progetto nasce dall’idea di dare un carattere unitario e riconoscibile ad un’area attualmente caratterizzata da singoli edifici che semplicemente si susseguono l’uno dopo l’altro in modo paratattico. La volontà è invece quella di dar vita ad un vero e proprio “palazzo” dell’istruzione, caratterizzato da spazi privati e spazi pubblici, spazi aperti e spazi chiusi in grado di dare una molteplicità di risposte e soluzioni alla complessità della società odierna galeatese. Proprio lo spazio pubblico è infatti il vero motore dell’intervento; quello spazio pubblico attualmente negato a Galeata, che si è vista mutilata nella parte centrale del suo centro storico sventrato alla fine dell’Ottocento per la costruzione della strada statale bidentina, diventa ora generatore di nuove relazioni con gli edifici dell’area e di nuove dinamiche tra il plesso scolastico e la città grazie alla realizzazione di corti aperte e terrazzate, piazze e strade pedonali che fungono sia da giardini sia da spazi espositivi o comunque spazi polifunzionali che possono accogliere eventi nei vari mesi dell’anno, entrando così a far parte di quella serie di attrezzature a servizio delle manifestazioni culturali in cui è sempre attiva la valle del Bidente e la comunità di Galeata. La scuola d’infanzia e di istruzione primaria viene così a configurarsi non solo come il primo luogo della crescita culturale del bambino, ma anche come primo luogo di integrazione sociale, perché il nuovo progetto genera all’interno e all’esterno degli edifici occasioni di incontro e confronto tra gli scolari grazie all’attenzione riservata agli spazi per le attività di interciclo e per le attività libere. Inoltre l’area viene dotata di un centro maternità/consultorio dove sono collocati servizi di assistenza per le donne in gravidanza e dove le stesse possono confrontare e condividere la propria esperienza con le altre future mamme. L’intero intervento è guidato a livello progettuale anche da criteri di ecoefficienza come educazione alla responsabilità ambientale.

Retrofitting boreholes contaminated with iron in rural Uganda

During my Peace Corps service as a community health liaison in rural Uganda I noticed that many improved water wells in our area had been abandoned. The communities described the water in these wells as being reddish in color, having a foul taste and odor, discoloring clothes and food, and not able to produce lather for washing. Personal investigations and an initial literature search suggested that the primary contaminant was iron. The water in these wells had a low pH and a rusty metallic smell. The water produced early in the morning appeared very red but the water became more transparent as pumping continued. The iron components of many of these wells experienced accelerated corrosion resulting in frequent pump failure. This rapid corrosion coupled with the timing of the onset of iron contamination (months to years after these wells were completed) suggests that the most likely cause of the poor quality water was iron related bacteria and/or sulphate reducing bacteria. This report describes a remedy for iron contamination employed at 5 wells. The remedy involved disinfecting the wells with chlorine and replacing iron pump components with plastic and stainless steel. Iron concentrations in the wells were less than 1 mg/L when the wells were drilled but ranged from 2.5 to 40 mg/L prior to the remedy. After the remedy was applied, the total iron concentrations returned to levels below 1 mg/L. The presence of iron related bacteria was measured in all of these wells using Biological Activity Reaction Tests. Although IRB are still present in all the wells, the dissolved iron concentrations remain less than 1 mg/L. This remedy is practical for rural areas because the work can be performed with only hand tools and costs less than US $850. Because the source of iron contamination is removed in this approach, substantial follow-up maintenance is not necessary.

Low-cost retrofitting solutions for RC frames using masonry infill panels

A large number of reinforced concrete (RC) frame structures built in earthquake-prone areas such as Haiti are vulnerable to strong ground motions. Structures in developing countries need low-cost seismic retrofit solutions to reduce their vulnerability. This paper investigates the feasibility of using masonry infill walls to reduce deformations and damage caused by strong ground motions in brittle and weak RC frames designed only for gravity loads. A numerical experiment was conducted in which several idealized prototypes representing RC frame structures of school buildings damaged during the Port-au-Prince earthquake (Haiti, 2010) were strengthened by adding elements representing masonry infill walls arranged in different configurations. Each configuration was characterized by the ratio Rm of the area of walls in the direction of the ground motion (in plan) installed in each story to the total floor area. The numerical representations of these idealized RC frame structures with different values of Rm were (hypothetically) subjected to three major earthquakes with peak ground accelerations of approximately 0.5g. The results of the non-linear dynamic response analyses were summarized in tentative relationships between Rm and four parameters commonly used to characterize the seismic response of structures: interstory drift, Park and Ang indexes of damage, and total amount of energy dissipated by the main frame. It was found that Rm=4% is a reasonable minimum design value for seismic retrofitting purposes in cases in which available resources are not sufficient to afford conventional retrofit measures.

A damage model for seismic retrofitting of structures

Numerous damage models have been developed in order to analyse the seismic behavior. Among the different possibilities existing in the literature, it is very clear that models developed along the lines of Continuum Damage Mechanics are more consistent with the definition of damage like a phenomenon with mechanical consequences as they include explicitly the coupling between damage and mechanical behavior. On the other hand, for seismic processes, phenomena such as low cycle fatigue may have a pronounced effect on the overall behavior of the frames and, therefore, its consideration turns out to be very important. However, many of existing models evaluate the damage only as a function of the maximum amplitude of cyclic deformation without considering the number of cycles. In this paper, a generalization of the simplified model proposed by Flórez is made in order to include the low cycle fatigue. Such model employs in its formulation irreversible thermodynamics and internal state variable theory.

A computer program for bridge retrofitting

This paper summarizes the work developed in order to establish a framework for seismic retrofitting of bridges. In this context, the first objetive is to find a numerical model to evaluate the damage induced in a structure, under seismic action, as an index of its vulnerability. The model used has the adventage that is based on concepts of fracture mechanics and concentrated plasticity. As a result, the work is based on basic principles. The performance of this model is being evaluated. Some results of the computer program developed for this purpose are shown.

Construction cost and energy consumption resulting from energy retrofitting in an apartment building in Madrid (Spain).

This theoretical study analyzes the relation between the measures necessesary for the energy retrofitting of a residential building constructed in Madrid, their cost and the improvement of the energy rating of the dwellings. The aim of this work is to establish an evaluation methodology that allows developers and architects to obtain conclusions and orientates therm in the decisioin-making process. It will allow finding the most suitable cost-effective solutions in each case. This paper describes the methodology and the findings obtained. Energy retrofitting and the improvement of the energy behaviour of the building depend on the selection of the retrofitting solutions and also on the investment. In this case study to achieve the best energy rates it is necessary to improve the thermal performance of the envelope as well as the energy systems. Energy retrofitting means an increase in property value but it can't only be considered in economic terms. It is necessary to take into account unquantifiable aspects as increased comfort, improved sound insulation, livability, health, or the elimination of energy poverty situations.