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Chapter 6 : Damage Estimation (3) Discussion Generally, it is well known that deformation of linear structures such as pipelines is generated by ground deformation during an earthquake. Many cases of heavy damage, such as broken pipes, caused by past earthquakes have been reported due to liquefaction and / or slope failure. In the Boumerdes Earthquake, no damage associated with the sewerage system was reported. However, the pipelines located in the “high risk” and “relatively high risk” areas have the highest priority to be assessed for seismic vulnerability if an aseismic assessment for the sewerage pipeline is undertaken. 6-3-6 Electric Power Supply Cable Electric power supply cables are classified into 3 types by distribution voltage, these being high voltage (220,000V or 60,000V), medium voltage (30,000V for rural areas or 10,000V for urbanized areas) and low voltage (others) cables as described in the section 4-2-7. The high voltage cables are supported by power pylons or buried underground. The design of these installations included aseismic considerations and therefore, there have been only a few records of damage due to past earthquakes. Hence, vulnerability of the high voltage cables for the scenario earthquake was evaluated qualitatively by overlaying the cable locations on the geo-hazard maps. The medium voltage cables will suffer damage due to the scenario earthquake, which will be influenced by various activities. The electric power supply cables in Japan are 6,600V, which is similar to the medium voltage cables in Algiers. Some damage estimation methods for the cables are recommended in Japan. The low voltage cables in the Wilaya of Algiers are very complicated and are distributed generally along the buildings. Damage to these cables due to the scenario earthquake is estimated as being comparable to building damage. Hence, the damage estimation of the cables is beyond the scope of this section. (1) Medium Voltage Cables 1) Damage Function The basic concept of the damage function is based on the Disaster Prevention Council of the Tokyo Metropolitan Area in 1997. The concept recommends 2 damage function curves in which one is for the aerial cables and the other is for underground cables. In this study, the damage functions applied were examined with the counterpart, and then we applied the following damage function curve shown in Figure 6-46. 6-69 Final Report 25 25 Aerial Cable Underground Cable PL=0 PL=0 20 0<PL≤5 20 0<PL≤5 5<PL≤15 5<PL≤15 15<PL 15<PL ) ) 15 15 10 10 Damage Ratio (% Ratio Damage Damage Ratio (% Ratio Damage 5 5 0 0 8.0 9.0 10.0 11.0 12.0 8.0 9.0 10.0 11.0 12.0 MSK MSK Figure 6-46 Damage Function Curve for Medium Voltage Cables In each grid sector, the damage function gives the damage ratio corresponding with an MSK value, and that ratio multiplied by the total length of pipe is the damage cable length. 2) Results and Discussion As a result, the length of damage in each 250 m grid zone was calculated by the damage ratio multiplied by the total length of the cables. Figure 6-47 to Figure 6-48 shows the result of the damage estimation for medium voltage cable by 250 m grid zone. The damage length will be concentrated in the central part of the study area for the Khair al Din scenario and eastern part of the study area for the Zemmouri scenario. Table 6-30 shows the tabulation of damage points by commune. 6-70 Chapter 6 : Damage Estimation Projection: U.T.M. Zone 31 Coordinate System: Nord Sahara 1959 Ellipsoide: Clarke 1880 490000 495000 500000 505000 510000 515000 520000 525000 4075000 4075000 1625 1640 1624 1606 1644 1605 1611 1639 1608 1607 1632 4070000 1601 4070000 1610 1622 1602 1623 1627 1604 1630 1628 1603 1617 1609 1629 1631 4065000 4065000 1618 1619 1621 1612 1616 1613 Legend 1620 Commune Boundary No Cable 2.01 - 4.00 1615 Expressway Slightly Damage 4.01 - 6.00 1626 National Road 0.01 - 2.00 (m/grid) 6.01 - 14.80 4060000 Railway 4060000 Water Body 490000 495000 500000 505000 510000 515000 520000 525000 Figure 6-47 Damage Length of Medium Voltage Cable: Khair al Din Projection: U.T.M. Zone 31 Coordinate System: Nord Sahara 1959 Ellipsoide: Clarke 1880 490000 495000 500000 505000 510000 515000 520000 525000 4075000 4075000 1625 1640 1624 1606 1644 1605 1611 1639 1608 1607 1632 4070000 1601 4070000 1610 1622 1602 1623 1627 1604 1630 1628 1603 1617 1609 1629 1631 4065000 4065000 1618 1619 1621 1612 1616 1613 Legend 1620 Commune Boundary No Cable 2.01 - 4.00 1615 Expressway Slightly Damage 4.01 - 6.00 1626 National Road 0.01 - 2.00(m/grid) 6.01 - 14.80 4060000 Railway 4060000 Water Body 490000 495000 500000 505000 510000 515000 520000 525000 Figure 6-48 Damage Length of Medium Voltage Cable: Zemmouri 6-71 Final Report Table 6-30 Summary of Damage Length of Medium Voltage Cable by Commune Length Damage Length (m) (m) (km) Khair al Din Zemmouri Commune Under- Under- Under- Aerial Total Aerial Total Aerial Total ground ground ground ALGER CENTRE - 59,806 59.8 - 208 208 - 15 15 SIDI M’HAMED - 40,903 40.9 - 80 80 - 0 0 EL MADANIA - 22,833 22.8 - 52 52 - 7 7 HAMMA EL ANNASSER - 42,397 42.4 - 81 81 - 3 3 BAB EL OUED - 10,843 10.8 - 16 16 - 0 0 BOLOGHINE IBNOU ZIRI 728 10,339 11.1 0 15 15 0 0 0 CASBAH - 12,95613.0 - 19 19 - 0 0 OUED KORICHE - 14,017 14.0 - 27 27 - 1 1 BIR MOURAD RAIS - 22,798 22.8 - 35 35 - 0 0 EL BIAR - 33,051 33.1 - 106 106 - 4 4 BOUZAREAH 5,994 39,432 45.4 2 60 62 0 0 0 BIRKHADEM 2,057 2,230 4.3 1 2 3 0 0 0 EL HARRACH 13,151 11,516 24.7 11 29 40 6 19 25 OUED SMAR 3,284 8,468 11.8 3 17 20 3 24 27 BOUROUBA 2,230 2,553 4.8 3 7 10 1 5 6 HUSSEIN DEY - 38,585 38.6 - 93 93 - 31 31 KOUBA 1,914 68,190 70.1 1 118 119 0 18 18 BACHDJARAH - 30,68330.7 - 60 60 - 27 27 DAR EL BEIDA 8,652 11,509 20.2 17 32 49 30 57 87 BEB EZZOUAR 4,751 21,997 26.7 5 61 66 5 72 77 BEN AKNOUN - 35,025 35.0 - 70 70 - 0 0 DELY BRAHIM 3,617 1,789 5.4 3 3 6 0 0 0 EL HAMMAMET 1,908 5,795 7.7 2 9 11 0 0 0 RAIS HAMIDOU 34 6,241 6.3 0 11 11 0 0 0 DJASR KASANTINA 15,646 3,578 19.2 8 6 14 1 2 3 EL MOURADIA - 17,339 17.3 - 39 39 - 2 2 HYDRA - 39,17039.2 - 71 71 - 0 0 MOUHAMMADIA 520 15,526 16.0 1 40 41 0 32 32 BORDJ EL KIFFAN 21,617 4,479 26.1 70 15 85 91 17 108 EL MAGHARIA - 12,780 12.8 - 30 30 - 12 12 BENI MESSOUS 4,298 2,949 7.2 5 4 9 0 0 0 BORDJ EL BAHRI 14,515 8,639 23.2 17 20 37 20 23 43 EL MARSA 3,295 4,976 8.3 5 10 15 6 12 18 AIN BENIAN 15,588 7,936 23.5 45 19 64 0 0 0 Total 123,797 671,326 795.2 199 1,465 1,664 163 383 546 Khair al Din Damage Length of Medium Voltage Cable (m) Zemmouri Damage Length of Medium Voltage Cable (m) 0 20 40 60 80 100 120 140 160 180 200 220 0 20 40 60 80 100 120 140 160 180 200 220 ALGER CENTRE ALGER CENTRE SIDI M'HAMED SIDI M'HAMED EL MADANIA EL MADANIA HAMMA EL HAMMA EL BAB EL OUED BAB EL OUED BOLOGHINE BOLOGHINE CASBAH CASBAH OUED KORICHE OUED KORICHE BIR MOURAD RAIS BIR MOURAD RAIS EL BIAR EL BIAR BOUZAREAH BOUZAREAH BIRKHADEM BIRKHADEM EL HARAACH EL HARAACH OUED SMAR OUED SMAR BOUROUBA BOUROUBA HUSSEIN DEY HUSSEIN DEY KOUBA KOUBA BACHDJARAH BACHDJARAH DAR EL BEIDA DAR EL BEIDA BEB EZZOUAR Aerial Cable BEB EZZOUAR Aerial Cable BEN AKNOUN BEN AKNOUN DELY BRAHIM Underground Cable DELY BRAHIM Underground Cable EL HAMMAMET EL HAMMAMET RAIS HAMIDOU RAIS HAMIDOU DJASR KASANTINA DJASR KASANTINA EL MOURADIA EL MOURADIA HYDRA HYDRA MOUHAMMADIA MOUHAMMADIA BORDJ EL KIFFAN BORDJ EL KIFFAN EL MAGHARIA EL MAGHARIA BENI MESSOUS BENI MESSOUS BORDJ EL BAHRI BORDJ EL BAHRI EL MARSA EL MARSA AIN BENIAN AIN BENIAN 6-72 Chapter 6 : Damage Estimation The commune that is projected to suffer the most damage is Alger Center for the Khair al Din case and Bordj El Kiffan for the Zemmouri case. In the most recent Boumerdes Earthquake, damage to the electric facilities was reported, while there were no reports about damage to the medium voltage cables. It is estimated On the basis of the above mentioned past damage records it is projected that the damage to the medium voltage cable may not be very extensive. The result of the damage estimation also shows that the damage length is not very great (1,664 m for Khair al Din, 546 m for Zemmouri) and the damage ratio is not very high (0.21 % for Khair al Din, 0.056 % for Zemmouri).