This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
Concrete Beams And Lintels. When these are to be made, they should be formed of concrete and twisted iron or steel rods. Fig. 70 indicates the method of construction; a shows the concrete beam carrying the wall e; b, the lower range of twisted bars, 1 inch in diameter; d, other bars placed near the top of each lintel, where it comes over a pier or column, thus practically making a continuous girder; and c, one of the supports of the beam.
136. Fireproof Vaults.
Another of the numerous uses to which concrete is put is in the construction of fireproof vaults, for which it forms a very valuable material, remaining intact even if the building is wholly destroyed. The concrete is laid, as before described, in a monolithic mass. Rails, etc. are frequently embedded in the concrete to stiffen it, as well as to make it difficult to cut through by burglars. The vault is further rendered proof against thieves by laying copper wires at short spaces throughout the concrete, forming a continuous circuit, and suitably connected with an alarm.