256 



BRIDGE ABUTMENTS AND PIERS. 



CHAP. VI. 



bottom of the tube, the piles being sawed off below the water line. The piles should extend at 

 least two diameters of the tube above the bottom. The tubes are braced transversely by means 

 of struts and tension diagonals above high water and by diaphragm bracing below high water. 

 Where the piers will be subject to blows from floating drift or logs they should be protected by a 

 timber cribwork or other device. 



Cooper's Standards. The tubular piers in Fig. 14 are from Cooper's "General Specifications 

 for Foundations and Substructures for Highway and Electric Railway Bridges." Cooper specifies 



j WaFfr*** 



Ground, 



OF MASONRY ABUTMENTS 

 WJTH WING WALLS 



Section A~B 



(a) HIGHWAY ABUTMENT WITH WWG WALLS 



iv - center to center oF trusses, 

 /4 ft For sing/e track, 26 Ft- For 

 double track- 



APPROXIMATE QUANTITIES IN Cu> YDS- 



OF ONE MASONRY ABUTMENT 



WITHOUT WING WALLS 



_t 



Ground. 



a-?00ff.5pari 



jjj-- : --- ----;[ At 'any 'po/'nt mm/mum 



^ a -75~ff~5pan &** ''&**. 



(I?) HIGHWAY ABUTMENT WITHOUT WIHG WALLS 



FIG. 7. MASONRY ABUTMENTS FOR ELECTRIC RAILWAY AND HIGHWAY BRIDGES. 



COOPER'S STANDARDS. 



a minimum thickness of f in. for plates below and | in. above the high water. The minimum size 

 of tubular piers are as given in Fig. 14. 



A steel tubular pier with a timber crib protection is given in Fig. 14. The crib is filled with 

 loose rock. 



A steel oblong pier, as designed by Cooper, is given in Fig. 15. The center of the truss is to 

 come a/2 + one ft. from the end of the pier. The width c, as specified by Cooper, is given in 



Fig- 15- 



American Bridge Company Standards. The American Bridge Company's standard tubular 

 piers are shown in Fig. 16. The minimum diameters for a height of 15 feet to carry a single span, 



