Damage of Bridges Resulting from Surface Rupture of Faults in the ...

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Photo 15 Damage Evaluation of Pile Foundation the most decks in the west from the fault rupture moved in the west direction while the most decks in the east of the fault rupture moved in the east direction. If it was correct, the direction of movement of the decks was not consistent to the right lateral slip. This requires more detailed survey of the damage and analysis. Photo 12 shows damage of an energy dissipating unit and a viscous damper stopper at Pier 48R. The C-shaped energy dissipating elements suffered damage, as shown in Photo 13, resulting from an excessive movement of the deck. 30mm diameter bolts that connected the elements to the frame ruptured. Photo 14 shows a set of cable restrainers at a deck end. It seemed that although the cable restrainers were effective to prevent collapse of the Viaduct, the gap of the cable restrainers was longer for preventing damage of the energy dissipating unit. Some pile foundations where the fault rupture crossed the Viaduct rotated 9) . Photo 15 shows the survey of damage after removing the soils. 4. CHI-CHI, TAIWAN EARTHQUAKE (1) Tectonic Ground Movement and Ground Motion The earthquake was induced by the Che-Long-Pu Fault. It was a thrust fault, and surface rupture occurred over 70km between Min-Ju and Tungshih. Eastern Taiwan is a tongue of the Philippine Sea tectonic plate that is over-thrusting the Eurasia plate. As shown in Fig. 13, damage occurred in Shihkang region, Tungshih region, Taiping, Wufeng and Tsaotun region, Nantou region, Chi Chi region, and Mingchien and Chushan region. Figs. 14 and 15 show the ground accelerations recorded at Shikhkang (TCU068), Taichung (TCU082) and Nantou (TCU076) and their response acceleration of 0.05 damping ratio, respectively 10) . Longer period pulses were included in the ground accelerations measured at north. In particular, EW component at Shikhkang had a single pulse with peak acceleration of 4.9 m/s 2 . Response acceleration of 0.05 damping ratio was about 1.5g at 0.5 second in the record. Fig. 16 compares the record at Shikhkang (TCU068) with the ground accelerations recorded at Bolu (L-component) and Duzce (L-component) in the Duzce Earthquake (refer to Fig. 11), Sylmar parking lot (NS-component) in the 1994 Northridge Earthquake and JMA Kobe Observatory in the 1995 Hyogo-ken Nanbu Earthquake. It is noteworthy that although the JMA Kobe record had the highest response acceleration at 0.5-1 second, the Shikhkang record had higher response acceleration than any other records at over 2 second. In the Chi Chi Earthquake, at least eight bridges (Bei-Fong Bridge, Chang-Geng Great Bridge, Shc- Wci Bridge, Yi-Jian Bridge, Wu-Shi Bridge, Pin- Ling Bridge, Mou-Loh-Shi Bridge, Min-Ju Great Bridge, and Tong-Tou Bridge) collapsed, and a 1), 11), number of bridges suffered extensive damage 12), 13) . Most of them suffered damage resulting from the fault rupture. Two bridges that suffered damage from the fault movement are described below. (2) Collapse of Bei-Fong Bridge Bei-Fong Bridge was located downstream of the Shikhkang Dam. Resulting from the fault rupture, a waterfall was created about 100m upstream of the bridge. It was of 13-span simply supported I-beam girder constructed in 1991. The south most three spans collapsed as shown in Fig. 17 with other spans being free from damage. The abutments, piers and decks are numbered herein from north to south. A2, P12 and P11 were upheaved about 3-4m, and P12 and A2 were laterally displaced about 3.5m and 4m, respectively, in downstream direction (west) as shown in Photo 16. D13 was resting on the slope of river embankment with the north end being dislodged 6.6m south from the original position. Fig. 18 shows the location of fault investigated by the Taiwan Geological Survey and Otsuki, K., 180
Root 1 Expressway Root 13 Root 3 Fengyuan Bei-Fong Br. Chang-Geng Great Br. Shc-Wci Br. Don-F ong Br. Tungshih Taichung Tali Wufeng Changhua Tsaotun Nantou Yi-Jian Br. Wu-Shi Br. Che-Long-Pu Fault Yen-Fong Br. Pin-Ling Br. Root 14 Mou-Loh-Shi Br. Puli Pin-Ling Br. Nan-Gang Br. Rui-Mei Br. Juin-Gong Br. Chungliao Mingchien Min-Ju Great Br. Chichi Yen-Pin Br. Chushan Shuili Chi-Da Br. Chi-Chi Br. Ling-Mei Great Br. Ling-Mei Br. Sun Moon Lake Tong-Tou Br. 0 10km 20km Fig.13 Damaged Bridges, Chi-Chi Earthquake Tohoku University. Most likely the fault crossed the bridge between A2 and P12 at an angle of about 42- degree. From the fact that P12 was laterally displaced in west, and that D11 and D12 clockwise rotated (20-40-degree), it appeared that the fault rupture crossed the bridge between A2 and P11 as shown in Fig. 19. If one idealizes the fault rupture at south of the fault relative to the north, the transverse and the longitudinal displacements of ground may be represented as (refer to Fig. 19) d TR =−D 0 sinθ d LG =−D 0 cosθ (3) in which D 0 is the fault displacement. Substituting d TR ≈ -4m and θ ≈42-degree into Eq. (3), one obtains D 0 ≈ -6m and d LG ≈ -4.5m. The 181
Page 1 and 2: Seismic Fault-induced Failures, 171
Page 3 and 4: Photo 1 4.3m Offset of a Concrete F
Page 5 and 6: Fig.7 Section of Piers, Arifiye Ove
Page 7 and 8: Acceleration (g) Acceleration (g) A
Page 9: Photo 9 Bolu Viaduct Photo 10 Girde
Page 13 and 14: 2 Acceleration (g) 1.5 1 0.5 NS EW
Page 15 and 16: D13 D12 D11 D10 S N About 25m D1 P1
Page 17 and 18: North Side South Side Root 3 N60E
Page 19 and 20: 4) Bogazici University Kandilli Obs

Damage of Bridges Resulting from Surface Rupture of Faults in the ...

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