Zoekresultaten

Computational modelling of damage accumulation in unreinforced masonry Dutch constructions subjected to induced seismicity

This paper aims to quantify the cumulative damage of unreinforced masonry (URM) subjected to induced seismicity. A numerical model based on discrete element method (DEM) has been develop and was able to represented masonry wall panels with and without openings; which are common typologies of domestic houses in the Groningen gas field in the Netherlands. Within DEM, masonry units were represented as a series of discrete blocks bonded together with zero-thickness interfaces, representing mortar, which can open and close according to the stresses applied on them. Initially, the numerical model has been validated against the experimental data reported in the literature. It was assumed that the bricks would exhibit linear stress-strain behaviour and that opening and slip along the mortar joints would be the predominant failure mechanism. Then, accumulated damage within the seismic response of the masonry walls investigated by means of harmonic load excitations representative of the acceleration time histories recorded during induced seismicity events that occurred in Groningen, the Netherlands.

Publicatielijst Harmen Bijwaard

De publicatielijst bevat alle publicaties waar Harmen Bijwaard aan bijgedragen heeft in de periode 1998 - 2013

Review article: Natural hazard risk assessments at the global scale

Since 1990, natural hazards have led to over 1.6 million fatalities globally, and economic losses are estimated at an average of around USD 260–310 billion per year. The scientific and policy communities recognise the need to reduce these risks. As a result, the last decade has seen a rapid development of global models for assessing risk from natural hazards at the global scale. In this paper, we review the scientific literature on natural hazard risk assessments at the global scale, and we specifically examine whether and how they have examined future projections of hazard, exposure, and/or vulnerability. In doing so, we examine similarities and differences between the approaches taken across the different hazards, and we identify potential ways in which different hazard communities can learn from each other. For example, there are a number of global risk studies focusing on hydrological, climatological, and meteorological hazards that have included future projections and disaster risk reduction measures (in the case of floods), whereas fewer exist in the peer-reviewed literature for global studies related to geological hazards. On the other hand, studies of earthquake and tsunami risk are now using stochastic modelling approaches to allow for a fully probabilistic assessment of risk, which could benefit the modelling of risk from other hazards. Finally, we discuss opportunities for learning from methods and approaches being developed and applied to assess natural hazard risks at more continental or regional scales. Through this paper, we hope to encourage further dialogue on knowledge sharing between disciplines and communities working on different hazards and risk and at different spatial scales.

'No way! I'll stay! Who will get me out of here?'

Few studies have investigated staying intentions and house attachment of residents who are confronted with physical damage to their dwelling in a risk area. This paper examines whether and how homeowners who are confronted with human-induced risks and the consequences of gas extraction in the Dutch Groningen rural earthquake region are attached to their damaged dwellings and why they stay. A content analysis was performed on 92 published interviews with homeowners of damaged dwellings. Additionally, three semi-structured interviews were held with key journalists and a homeowner. The results show that the homeowners’ staying intentions are interrelated with their house attachment; moreover, their awareness of their house attachment arises precisely because of the damage. We identify five subdimensions of physical and social house attachment, related to family history, heritage, (agricultural) business, personal refurbishment, and cohabiting family members, which make homeowners want to stay. The family history is especially mentioned by mid-to-later life homeowners, while some younger homeowners emphasize social house attachment to their children.We conclude that a homeowner's decision to stay in a damaged dwelling is a continuous cycle of reconsideration and renegotiation, punctuated by potential new risks and damages influencing the house attachment and staying intentions. Based on the found dimensions of house attachment, policymakers in risk areas could apply different approaches to homeowners in case of damage repair, rebuilding, or relocation plans, as homeowners - even those with damaged dwellings - may prefer to stay.

Versterken "met gezond boerenverstand"

FRP versus traditional strengthening on a typical mid-rise Turkish RC building

This paper investigates the limits and efficacies of the Fiber Reinforced Polymer (FRP) material for strengthening mid-rise RC buildings against seismic actions. Turkey, the region of the highest seismic risk in Europe, is chosen as the case-study country, the building stock of which consists in its vast majority of mid-rise RC residential and/or commercial buildings. Strengthening with traditional methods is usually applied in most projects, as ordinary construction materials and no specialized workmanship are required. However, in cases of tight time constraints, architectural limitations, durability issues or higher demand for ductile performance, FRP material is often opted for since the most recent Turkish Earthquake Code allows engineers to employ this advanced-technology product to overcome issues of inadequate ductility or shear capacity of existing RC buildings. The paper compares strengthening of a characteristically typical mid-rise Turkish RC building by two methods, i.e., traditional column jacketing and FRP strengthening, evaluating their effectiveness with respect to the requirements of the Turkish Earthquake Code. The effect of FRP confinement is explicitly taken into account in the numerical model, unlike the common procedure followed according to which the demand on un-strengthened members is established and then mere section analyses are employed to meet the additional demands.