It's Sheer Weight That Keeps a Pier in Place 



Here is an inexpensive way to get the necessary amount 



The new type of pier instead of being cast into a solid block is made in the form of a 

 hollow semi-circle the ends of which are extended backward in the form of two parallel walls 



TRESTLE 

 ■■"^BRIDGE SEAT 



ONLY a few years ago, 

 the piers which sup- 

 ported the shore ends 

 of a highway bridge were 

 made of huge, massive 

 blocks of concrete. The 

 sheer weight of the con- 

 crete steadied them and 

 prevented their slipping 

 away or overturning with 

 the bridge into the river. 

 Upon this principle of op- 

 eration, however, these 

 piers could never be made too large. 

 Indeed, the danger lay in possibly making 

 them too small. Evidently, they were 

 very expensive. 



No wonder then that engineers have been 

 giving the problem of the highway bridge 

 much attention. The result has been most 

 satisfactory. An American engineer has 

 lately brought out a highway pier which 

 works on a more scientific principle. His 

 pier, illustrated in the accompanying photo- 

 graph, is just one half as expensive as the 

 older types, while in some cases, it has even 

 proved better and stronger than they could 

 have been. 



DOWNWARD SLOPE OF 

 ABUTMENT TO CONFORM 

 WITH EARTH FILL 



ABUTMENT PROJECTION 

 COVERED BY EARTH 



Plan of the new type of pier. 

 The convex face of the semi- 

 circular wall faces the river 



Instead of casting the 

 piers into a solid block, 

 those of the new type are 

 being made more in the 

 form of a nollow semi- 

 circle. The ends of this 

 semi-circle are prolonged 

 backwards in the form of 

 two parallel walls. The 

 convex face of the semi- 

 circular wall faces the river. 

 A wide rectangular-shaped 

 notch is left at the top of 

 this part, directly in front. The land-end 

 of the bridge fits into the bridge-seat thus 

 formed. The prolonged ends of the pier 

 slope downwards away from the river. 



The piers are made a foot thick all 

 around. A number of heavy steel rods are 

 cast in the concrete of each pier. These 

 rods run nearly parallel with each other 

 around the piers as shown in the diagram 

 and they greatly reinforce the entire 

 structure. Earth is dumped into the pier 

 to fill up the hollow inside. The two 

 extending walls are then deeply buried in 

 earth also. It is the weight of this earth 

 which prevents the pier from slipping. 



600 



