Risk assessments on trees in urban areas and roadside plantings have become common practice and a large body of information exists on qualitative aspects on the risks of tree failure. Quantitative analysis of financial damage due to tree failure is generally lacking. The objective of this paper is to determine the amount of tree failure related property damage and to derive possible trends in the number of cases and monetary claims and compensations. This paper presents the analysis of 1610 observations on urban tree failure in the Netherlands. The data originate from two different sources, i.e. jurisprudence (4% of the data) and 21 municipalities (96%). The data covers property damage in urban areas between the early sixties and 2010. Within municipalities, paid compensations due to tree failure are found to range from €0 to € 49,296 with an average of €2,244 per paid compensation. Results demonstrate a significant annual increase in tree failure as well as in paid compensations.
MULTIFILE
Groningen gas field is the largest on-land gas resource in the world and is beingexploited since 1963. There are damaging earthquakes, the largest of which was 3.6 magnitude. The recursive induced earthquakes are often blamed for triggering the structural damages in thousands of houses in the area. A damage claim procedure takes place after each significantly felt earthquake. The liability of the exploiting company is related to the damages and the engineering firms and experts are asked to correlate the claimed damages with a past earthquake. Structures in the region present high vulnerabilities to the lateral forces, soilproperties are quite unfavourable for seismic resistance, and structural damages are present even without earthquakes. This situation creates a dispute area where one can claim that most structures in the region were already damaged because of the fact that the soil is soft, the ground water table oscillates, and structures are vulnerable to external conditions anyhow and deteriorate in time, which can be the main cause of such structural damages. This ambiguity of damage vs earthquake correlation is one of the main sources of the public unrest in the area up until today. This study presents the perspective of people in the region in terms of liveability and the social acceptance of earthquakes in their lives. An attempt has been made to translate these social effects and expectations into structural performance metrics for ordinary houses in the region. A new seismic design and assessment approach, called Comfort Level Earthquake (CLE) has been proposed.
DOCUMENT
Seismic risk assessment of two real RC multi-story buildings, located on similar soil profile in Kocaeli, is conducted in respect to code-based linear and nonlinear approaches, as well as to P25-v2 Method, a recently suggested method for risk evaluation and preliminary assessment of existing buildings against life-loss. Twenty-five different parameters and seven different collapse criteria are taken into consideration in the suggested P25-v2 Method, including soil and topographic conditions, earthquake demand, various structural irregularities, material and geometrical properties, and location of the buildings. After summarizing the different methodologies and describing the case study buildings, 3D linear-elastic and static nonlinear analyses are performed in parallel to the application of the P25 Method-v2. One of the two case study buildings totally collapsed during 1999 Kocaeli Earthquake, while the other survived with negligible damage, noting that both had legal construction and occupation permissions. SAP2000 and SeismoStruct software packages have been utilised for the analysis procedure to find out the damage states of the structural members at critical stories and to determine the performance levels of the case study buildings. The code-based performance levels and the final performance scores obtained by the preliminary assessment technique are compared in order to underline the existence of the correlation between the detailed procedure and the suggested preliminary assessment technique with the real damage state. Consequently, structural inadequacies, weak points of the buildings and failure reasons are also discussed in this paper.
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