Production Scenario "Basispad Kabinet"
Yüklə 9,41 Mb. Pdf görüntüsü
|
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018 59
5 Risk Assessment 5.1 Local Personal Risk The Minister of Economic Affairs and Climate Policy has confirmed that he has adopted the Meijdam Norm for Groningen gas production related risks, this norm states that buildings should meet the same 10 -5 /year level as is generally used in the Netherlands, but that for a transition period a level of 10 -4 /year should apply. This report shows the number of houses where the risk exceeds one of these two levels, without addressing which of the two levels applies for an individual house, as such is the domain of the NCG who currently directs the strengthening effort.
Figures 5.1a and 5.1b show the number of buildings exceeding a mean annual Local Personal Risk (LPR) for each year of the 10-year period 2018 to 2027. The grey bands in these LPR-graphs indicate the uncertainty range. Figure 5-2 shows the LPR-graphs for the three five-year periods 2018 to 2022, 2023 to 2027 and 2028 to 2032. The impact of the buildings already strengthened to date has not been incorporated in this assessment. The development of the mean LPR for the Groningen building stock over the period 2018 to 2027 is shown in figure 5.3. The number of buildings exceeding the Meijdam norm of mean LPR 10 -5 /year shows a declining trend from 2021 onwards. This is particularly evident for the years 2021 to 2024 the number of buildings exceeding this norm declines noticeably, as a result of the decline in gas production when the nitrogen blending plant comes on stream. For each year in the period 2018 to 2027, tables 5-1a and 5-1b, show the number of buildings for three different probabilistic assessments: ▪
-5 /year level ▪
-4 /year level During the period 2021 to 2023, the number of buildings where the 10 -5 /year norm is not met is assessed to decrease from just over 1,100 in 2021 to about 250 in 2023 and less than one hundred in 2024. The data captured tables 5-1a and 5-1b is also shown in figures 5-4 and 5-5. In figure 5-4 shows number of buildings where the LPR exceeds the 10 -4 /year and 10 -5 /year, for different scenarios. The average temperature scenario and several cold and warm weather scenarios are shown. For instance, the cold temperature scenario for the gas-year 2018/2019 is shown with all following years being average temperate years. Cold and warm temperature scenarios for other gas-years are also shown. For comparison the results for the 24 Bcm/year scenario from November 2017 are also shown. In figure 5-5, the cold and warm temperature scenario as specified in the Expectation Letter are shown. The cold temperature (and the warm temperature) scenarios are based on the individual year being cold (or warm), but all preceding years and following years being average temperature years. The LPR results can be disaggregated to show the separate contributions of the different building typologies (shown in figure 5-6d) as well as their collapse states to the LPR. Collapse State 1 refers for most typologies to partial collapse of façade walls, typically out-of-plane and generally to the outside of the building. Collapse State 2 and 3 are typically more severe, with collapse State 3 leading to global collapse of a significant part of the building. The measures required to strengthen the building will depend on the collapse state that contributes most to the LPR for each building typology. The numbers of buildings (for each building typology) exceeding a given average annual collapse rate for collapse states 1, 2 and 3 are shown in figure 5-6 (a-c). The building typologies with the highest average annual collapse rate for global collapse (i.e. collapse state 3) across the field are predominantly terraced buildings with large openings at the ground floor (URM4L), precast reinforced concrete buildings (PC4M) and barns (W2L).
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018 60
We note that the second paragraph of the above text is only valid for the 2022, 2024 and 2026 plots if the same three building typologies are highest on the y axis.
2018 2019 2020
2022 2023 Figure 5.1a Local Personal Risk graphs for the years 2018 to 2023. These show the number of houses that are exposed to a LPR. The black lines denote the mean and the dark grey areas the uncertainty bands. The two horizontal bands in light grey denote the LPR levels of the Meijdam-Norm.
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018 62
2025 2026
Figure 5.1b Local Personal Risk graphs for the years 2024 to 2027. These show the number of houses that are exposed to a LPR. The black lines denote the mean and the dark grey areas the uncertainty bands. The two horizontal bands in light grey denote the LPR levels of the Meijdam-Norm.
Yüklə 9,41 Mb. Dostları ilə paylaş:
|