DAMAGE TO BRIDGES DURING EARTHQUAKES 639 



The piling, v/hich affords no indication of relative movement from inclosing 

 earth, has dragged attached bents from vertical positions and jerked the super- 

 structure from opposite sides to the center line with violence, v/recking rails, bulg- 

 ing up stringers, forcing up the caps of bents v/hich were mortised with four-inch 

 tenons, and in general affording liberal indications of shortening of the distance 

 separating banks. (Pp. 304, 305.) 



Of culverts and trestles there were many which received serious 

 damage at the time of this earthquake, and all appear to have been 

 deformed by a longitudinal compression.^ 



THE MINO-OWARI EARTHQUAKE OF OCTOBER 28, 1891^ 



This earthquake has furnished some of the best illustrations any- 

 where available of the nature of damage to bridges during a destruc- 

 tive earthquake. 



The Bivfajima-Bashi, a v.'ide wooden carriage bridge across the Schonaigawa, 

 was completely wrecked. It lies in the bed of the river in a curious serpent-like 

 twisted form. The river is very lov/, and the continuity of the bridge v/as nov/here 

 actually broken, so it was possible to v/alk across, though the feat was not an easy 

 one on account of the angle at which the footway was canted. (See Fig. i, B.) 



A brick railway bridge near the Biv/ajima River presented a singular appear- 

 ance. The abutments which ordinarily had been perpendicular, had apparently 

 been pushed backward to the right and left, and the arch v/hich they ordinarily 

 supported lay in tv.'o huge quadrant shaped masses blocking up the roadway 

 betv/een them. (See Fig. 3, D.) 



Speaking of the Kisogawa bridge, Milne and Burton say: 



a) Approaches. — A more important feature is, however, the serpent-like 

 bending of the line. Not only have the metals been deflected, but the embank- 

 ment has suffered a parallel deformation. It seems as if the country here — and 

 similar appearances are presented at other places — had been subjected to a 

 permanent longitudinal compression. At each of these bends, although not 

 shov/n in the present picture, to the right and left of the line, there is generally 

 a slight compression in the general contour of the country which possibly may 

 mark the line of an ancient watercourse, in v/hich we may imagine that the 

 materials are softer than elsewhere. (See Fig. i. A.) 



b) Bridge. — The lateral shifting of the foundations by which the distances 

 between the piers have been reduced, has been the result of a permanent com- 

 pression which, had the bridge been represented by a line across the river bed, 

 would have been contorted into one or more snake-like bends. (See Fig. 3, A.) 



1 Loc. cit., pp 286, 290. 



2 John Milne and W. K. Burton, The Great Earthquake in Japan, 1891, Yoko- 

 hama, (Lane, Crawford & Co., 1892), 2d ed.. 



