RISK MANAGEMENT TOOL FOR IMPROVING PROJECT FLOWS FOR CONSTRUCTION PROJECTS ON EXISTING BUILDINGS

Old cores of European cities make more than 35% of the entire building stock in Europe, which and often form the social, financial, and touristic centers of cities. These old buildings require constant investments in terms of renewal and preservation to retain their usefulness. Existing risk management tools do not provide sufficient support when managing these types of projects. Hence, previously developed risk breakdown structures (RBSs) for projects on existing buildings were extended to enable simpler project management and clear visibility of critical risks. Previous studies focused on RBSs for construction projects in general. Research with respect on real life projects showed that some risk sources posed a greater threat and had more risk triggers than other risk sources. This study identified critical risk sources with respect to existing RBS and conducted a further analysis of these risk sources. The results of the study examined the fully developed RBS for existing building construction projects with further structuring of specific risk sources. Furthermore, the study identified stakeholders and assigned their risk resolution responsibilities

METODOLOGIJA ODABIRA TEHNOLOGIJE SEIZMIČKOG OJAČANJA ZIDANIH ZGRADA

When the decision has been made to seismically strengthen a building, in order to mitigate possible damaging effects of an earthquake, choice of seismic strengthening is entirely left to the expert. The choice is often made without any specific analyses of the need and implementation possibilities, but depends completely on the expert’s knowledge and experience. The article presents the development of the innovative approach to strengthening technique selection for existing buildings that incorporates all important elements that influence the strengthening selection process. The presented model is simple, quick, precise, allowing analytically supported decision making. Although the developed model is designed particularly for masonry buildings, decision support model for strengthening technique selection is adaptable to any building type.Kada je donesena odluka o potrebi za ojačanjem zgrade u cilju preventivne zaštite od potresa, kao pravilom, odabir ojačanja prepušten je stručnjaku. Odabir ojačanja se najčešće provodi bez konkretnih analiza mogućnosti i potreba za određenim pothvatom, već isključivo prema nahođenju i prošlom iskustvu stručnjaka. U članku se predstavlja proces razvoja inovativnog pristupa izboru tehnologija ojačanja postojećih zgrada, a kojim se uzimaju u obzir svi bitni elementi koji mogu utjecati na izbor ojačanja. Predstavljeni model je jednostavan, brz i precizan, te dozvoljava donošenje odluka na osnovu analitički dokazanih činjenica. Unatoč tomu što je model izrađen isključivo samo za zidane zgrade, model za izradu potpore odlučivanja pri odabiru tehnologije ojačanja je prilagodljiv bilo kojem tipu građevina

Post-earthquake damage assessment of buildings – procedure for conducting building inspections

Procjene oštećenja i uporabljivosti građevina u Hrvatskoj, iskočile su u prvi plan nakon potresa u Zagrebu 22. ožujka 2020. S obzirom na manjkavosti pripremne faze, pri čemu nije provedena edukacija stručnjaka prije potresa, nego u hodu, procjene su sadržavale dozu subjektivnosti i interpretacije na temelju znanja, iskustva, ali i intuicije pojedinaca. U radu je detaljno prikazana metodologija koja može pomoći u brzim procjenama te kod detaljnih inženjerskih pregleda koji se moraju napraviti prije obnove. Prikazana metodologija se može iskoristiti u slučaju novoga razornog potresa koji se može dogoditi već sutra.Assessments of building damage and usability were of primary importance after the Zagreb earthquake of 22 March 2020. Due to deficiencies of preparatory phase, where education of experts was not carried out before the earthquake, but later on, the assessments contained certain subjectivity and interpretations, based on knowledge and experience, but also on intuition of individuals. Detailed methodology, which should improve rapid assessments and detailed engineering inspections to be performed before reconstruction, is highlighted in the paper. This methodology may be utilized if another devastating earthquake occurs, which could happen already tomorrow

The Role of Disaster Risk Governance for Effective Post-Disaster Risk Management—Case of Croatia

Risk governance is mostly viewed through the lens of disaster or emergency management departments, agencies, or organizations. Visible in times of crises, risk governance is rarely seen as part of everyday public or private functions such as planning, social welfare, investments, or fiscal responsibilities. This paper emphasizes the importance of disaster risk governance in disaster risk management activities on the example of the post-disaster recovery of Croatia after a series of strong seismic events in mainland Croatia. The analysis is made based on a thorough review of national documents of Croatia and other selected countries overlapped with the national journals reporting on the situation from the affected areas. In accordance with the authors’ opinion, the necessary elements of disaster risk governance are clearly stated through the four Sendai framework priorities, and this statement is supported by the facts from the case study. Without either the political will or the enabling surrounding the disaster, risk management is next to impossible. The Croatian case study emphasizes the importance of disaster risk governance, showcasing the adaptation process for the post-disaster recovery process to start

Sustainability in architectural heritage: review of policies and practices

If sustainable development goals are to be achieved, it is necessary to consider refurbishment of architectural heritage buildings as well! As just 1% of buildings in the European Union have been built since 2006, it is essential to turn towards refurbishment of existing buildings if goals of sustainable development are to be achieved. Therefore, this article explores the ways in which sustainable development in construction is encouraged and achieved, especially concentrating on architectural heritage buildings. The idea of sustainable development revolves solely around carbon emissions, and therefore, historic buildings in Europe face the key issue of sustainability. Recently, there has been an increasing interest in reusing existing buildings through refurbishment and adaptive reuse where possible, as building reuse should offer environmental savings over demolition and new construction. In addition, despite popular belief, older buildings are capable of adapting to the new energy efficiency norms. This study explores the possibilities of encouraging complete refurbishment (including both sustainable renovation and strengthening) of historical buildings by exploring incentives used in Europe, the USA, Canada and New Zealand. Based on the literature review and best practices, the article concludes with recommendations on how to increase the positive investment flow of private capital into architectural heritage buildings, thus ensuring both preservation of heritage and achievement of sustainable development goals. The findings help both the user of the initiative on gaining insight into the intervention process that can be expected, as well as the local and regional governments interested in boosting adaptive reuse and refurbishment of existing buildings in order to achieve sustainable development goals

Methodologies for structural damage identification by means of dynamical testing

Modeliranje ponašanja stvarnih konstrukcija je složeno i sadrži mnoge nepoznate veličine: način gradnje, ugrađeni materijal, raspodjela mase i krutosti, stanje konstrukcije, itd. koje je nužno pretpostaviti. Ove nepoznanice čine nerazumnima primjenu složenih matematičkih modela, jer loši ulazni rezultati vode ka lošim izlaznim rezultatima, bez obzira na točnost primijenjenih matematičkih modela. Pojednostavnjeni modeli koji se baziraju na primjeni eksperimentalnih rezultata daju bolje uvide u stanje materijala i konstrukcija. Kvantitativno određivanje stvarnog stanja konstrukcije moguće je mjerenjem dinamičkog odgovora na ograničenom broju mjernih mjesta. Dinamičkim ispitivanjem dobivaju se: vlastite frekvencije, forme i koeficijenti prigušenja koji predstavljaju osobnu iskaznicu konstrukcije i sadrže u sebi sve bitne podatke o konstrukciji. Poznato je da se praćenjem stanja dinamičkih karakteristika dobiva dobra informacija o trenutnom stanju konstrukcije u eksploataciji. Moguće je na temelju razlike stanja dinamičkih karakteristika između dvaju razdoblja odrediti promjene krutosti konstrukcije odnosno ocijeniti mjesto i intenzitet oštećenja koja su u međuvremenu nastala. U radu su prikazane metodologije za identifikaciju i kvanitifikaciju intenziteta oštećenja na stvarnoj konstrukciji, a koja su bazirane na provedenim dinamičkim mjerenjima ambijentalnim vibracijama. Metodologije su kalibrirane i provjeravane na jednostavnim matematičkim i eksperimentalnim modelima s jednim i s tri stupnja slobode.Dynamic characteristics of the structure represent its personal card. By monitoring them it is possible to get relevant information about the structural state and its degradation. The differences in measured dynamic characteristics at two stages in the life of structure reveal change in the stiffness/mass of the structure, location of the change and it is possible to conclude about the size of change in regard to the initial state. Outlined are two methodologies for structural damage identification by means of dynamical testing. They have been calibrated on the simple models and have proven its applicability to the real building structure for which only a limited amount of measured data is available. Methodology 1 requires knowledge of the measured dynamical characteristics of a structure at its initial state and after the damaging event. By means of the structural identification from the measured dynamical characteristics and comparing the change of relative shear stiffness between the neighboring stories the location and amount of structural change/damage is estimated. Methodology 2 is used when there are no data about the initial structural dynamic characteristics. A structural model with the use of finite element is made for the structure in its undamaged state. Measured dynamic properties such as frequencies and mode shapes of the structure in its damaged state are also needed. Using system identification techniques on both data sets and using the method of relative shear stiffness or the method of residual forces the location and amount of the structural damage could be estimated. It is applicable for the structures that could be described by the FEM

ScienceDirect Risk Breakdown Structure for construction projects on existing buildings

Abstract Governments and private investors are increasingly becoming aware of the marketing power and the importance of seismic safety of old cores of their cities. Hereby the interest in preserving the original look and often even the original, but improved construction of the buildings becomes imperative and a demanding task for engineers and project managers. The main goal of project management is controlling the outcome of a project through control of elements like quality of the final product, costs and time, whereas practice shows that these types of projects very often overrun cost and time limits. Therefore these are the main research questions: Can construction projects on strengthening and preserving existing buildings be successfully governed with existing risk management tools? If not, how can we improve the existing risk management tools? In this paper development of a new risk breakdown structure for construction projects on existing and historical buildings is presented. The risk breakdown structure is developed based on previous project experiences and in collaboration with a series of experts

Eksperimentalno istraživanje zaštite erozijom ugroženih vodenih slapova na naslagama sedre - prirodne pejzažne, povijesne i kulturne vrijednosti na primjeru grada Jajaca

The possibilities of technical interventions in waterfall area formed in heterogeneous tuff sediments are described in this paper. The river Pliva\u27s waterfall was chosen for the test site, as it is a unique natural phenomenon placed in the middle of the old town of Jajce. The applicable methods for technical stabilization of waterfall are conditioned by natural, urban, architectural, historical and specific values of the town landscape. That is why that concrete or reinforced concrete structure should be avoided and priority given to binders for natural tuff detritus that do not change the shape or color of naturally hardened tuff are preferred. Laboratory experiments on a large number of samples have shown good results when micro-cement was injected into tuff beds, but the usability of other injection suspensions was also examined on the research region. The injection suspensions were adjusted to the tuff lithological composition. Comparisons of the control samples in laboratory and on site have shown acceptable results of the applied methods.U članku se opisuju mogućnosti prihvatljivih tehničkih intervencija u prostoru slapova formiranih u heterogenim naslagama sedre. Kao istražni poligon odabran je slap rijeke Plive, izuzetan prirodni fenomen smješten u samom središtu povijesnog grada Jajca. Metode istraživanja primjenjivosti tehničkih rješenja stabilnosti slapa uvjetovane prirodnim urbanističkim, arhitektonskim, povijesnim, te specifičnim pejzažnim vrijednostima gradskog prostora zbog čega betonske i armirano betonske konstrukcije treba izbjegavati, a prioritet dati stabiliziranju prirodnog sedrenog detritusa vezivima koja ne mijenjaju izgled i boju prirodno očvrsle sedre. Laboratorijski eksperimenti na velikom uzorku pokazali su dobru injektibilnost mikrocementa u sedreni detritus, a primjena ostalih suspenzija ispitivana je na istražnom poligonu gdje su injekcijske suspenzije prilagođavane litološkom sastavu sedrenih naslaga. Kontrolna ispitivanja u laboratoriju i na istražnom poligonu potvrdila su uspješnost primijenjenih metoda