INTRODUCTION. 



In preparing this book we have not attempted to give 

 tables which would enable an inexperienced person to 

 ilcsimi in reinforced concrete. To do so would, in our 

 opinion, be questionable engineering. We have endeavored 

 to collect such standard data as the designing engineer, 

 the engineer contractor and the superintending engineer 

 require for reference. In consequence we have omitted aJJ 

 unnecessary material, referring frequently to the most re- 

 cent and best works on reinforced concrete, and tho best 

 general handbooks. We do not claim to have made tests, 

 but we give, in the form of tables, many of the recent 

 tests, from which a comparative study may be made. 

 We have collected from the handbooks such data as is 

 universally required in this kind of construction. We have 

 prepared a special table for computing beams, which we 

 believe has advantages over other tables. We wish to 

 say to the reader, as a final word of caution: Unless you 

 are certain that you have analyzed all stresses in de- 

 signing your various members, don't attempt to design In 

 reinforced concrete. 



GENERAL NOTES. 



Capt. Sewell says concrete Is only affected by fire to a 

 depth of 14 to % In., except at exposed corners where 

 there Is a tendency to rounding off 3 in. radius. 



Use of flints is dangerous. 



Concrete should be mixed wet when applied to the 

 metal. Mixed too wet, concrete never attains its full 

 strength. 



To insure Impermeability a concrete must be made very 

 rich. Addition of slaked lime ensures closing of the pores. 

 Many use soft soap or caustic potash and alum. 2 Ibs. 

 soft soap, 12 Ibs. alum, and 30 gals, of water per cu. yd. 

 of mortar. 



Heads greater than 70 ft. are not advisable for large 

 diameter concrete pipes. 



Reinforced concrete is heavier than steel or Iron-work 

 for supporting the same load. There is a high percentage 

 of dead to live load. 



After the ultimate strength of the concrete is reached, 

 its modulus of elasticity becomes nil. 



On account of the monolithic nature of a structure, 

 heavy machinery causes little or no vibration. The driv- 

 ing of concrete piles also shows the resistance to shocks. 



Dampness causes elongation; dryness, a contraction of 

 concrete. The richness of the mixture plays a greater 



