NoTKs UPON Aj'rr.icATiON OF Rkinfokckd Concuetk. 73 



of two 'l in. round steel bars running the whole length of tlie beam. 

 On tlio lower or tension side are three 1 J in. <liaineter steel bars, also 

 running the whole length of the beam. Two bars of 1^ in. diameter 

 steel are placed above these, with the ends turned or trussed up close to 

 the compression side of the beam. These latter, as well as furnishing 

 resistance to tension, tcike up half the shear stresses over the supports. 

 The remainder of the shear tresses are provided for by diagonal wire 

 members. Jiesides the above reinforcement, four rods of 1?, in. 

 diameter are placed over each support to resist the stresses caused by 

 contrary flexure of the continut)us beam. 



The two longitudinal beams on the outer sides, which cany the 

 side-walks and parapet, are almost similarly reinforced to the centre 

 ones, but for obvious reasons are different in shape. 



The crown of the bridge and side-walks are of concrete 6 ins. 

 thick, reinforced with expanded metal ji in. by | in. and mesh 9 ins. 

 by G ins. 



Parapets. — The uprights for the parapets are moulded in sitn 

 around vertical bars cast into the side-walks. Ornamental panels 

 3 ins. thick reinforced were made ashore. They are dropped into 

 position into grooves prepared for them and capped with a coping or 

 lail also reinforced. To complete the bridge, a layer of tar macadam 

 is laid upon the roadway to take; the wear of vehicular tratiic. 



The details of approach roads, fences, kc, are of the usual char- 

 acter, and do not require describing. 



The departmental estimate of cost of the work was ^7000, and 

 the contract was let to Messrs. Knight tt Fulkestad of Port Elizabeth 

 for £6400. 



The author trusts that the introduction into the Cape Colony of 

 these modest examples of reinforced concrete structures w-ill be the 

 forei'unner of more important ones, and draw attention to an excel- 

 lent combination of materials so well adapted for engineering and 

 architectural Avorks, having in addition the properties of resisting the 

 ra\ages of decay and fire. 



As regards economy, there can be no doubt, moi'e especially in the 

 case of architectural work, where a saving of as )uuch as 30 per cent, 

 lias been effected by using reinforced concrete instead of steel struc- 

 tures. There is also the advantage to the community of making use 

 of the labour in the colony instead of sending money away for the 

 manufactured article. 



In conclusion, although mucli has been done towards tlie scientific 

 treatment of reinforced concrete, there is still scope for further research 

 before it can be dealt with expeditiously as homogeneous materials. 

 However, with the testimony of numerous examples of extensive 

 successful works executed in various countries, a considerable amount 

 of confidence can be placed upon reinforced concrete as a safe, cheap 

 and expeditious building material. 



