Ductility 



Its 

 Importance 



(2) The diamonds, or quadrilaterals, of the sheet under severe loading tend to close. The 

 effect of this contraction in the meshes is to give the fabric a ductility unencountered in any 

 other reinforcement having a high elastic limit. As this closing up of the meshes does not take 

 effect except under severe loading, to the advantages of a high elastic limit are added those of a 

 ductile material. Unless the slab is under-reinforced, when "Steelcrete" Expanded Metal fails, 

 it fails slowly. This feature will be appreciated by engineers and experts in building construction. 



(3) The effect of this closing up of the diamonds, in addition to giving the fabric ductility, 

 is to introduce a Compression into the concrete which at this point is in tension. This, as will be 

 noted at once, is highly beneficial to the slab, and greatly adds to its strength. This feature is 

 entirely unique with Expanded Metal. It is encountered in no other reinforcement, and is recog- 

 nized and highly commended by concrete experts everywhere who have tested this material to 

 destruction. 



To these three distinctive features of Expanded Metal may be added many others, such as 

 the perfect bond attained between the steel and the concrete; perfect distribution of the steel, 

 whereby the designer is assured that it will be located just where his calculations assumed it to 

 be, and numerous others. These points will now be taken up separately, that the importance of 

 each may be properly emphasized. We are able to satisfy the most skeptic in every case. We 

 have data and the results of tests on hand covering every feature. It is not possilble to give such 

 data in a brief circular such as this, owing to its volume. We will be glad to correspond with 

 any one who is sufficiently interested to go into the matter further with us. 



THE HIGH ELASTIC LIMIT. 



That the high elastic limit is an advantage in concrete reinforcement is a statement which 

 must be accompanied with certain reservations. In general, it may be stated that steel is a 

 ductile material in comparison with concrete. In concrete this quality is greatly lacking. If 

 concrete and steel are to work together, it is plain that they must stretch together. After the 

 steel has passed its elastic limit its elongation becomes so pronounced that the concrete cracks 

 and breaks, and to all intents and purposes the. beam has failed. Until this critical point has 

 been reached the deflection on a beam is negligible, and on a slab of small span is scarcely per- 

 ceptible. Evidently, high elastic limit .adds greatly to the load-bearing powers of the slab, sup- 

 plying a factor of safety not found in a soft steel. As long as tests are regarded as the basis 

 of comparison for steel reinforcements, so long will the materials possessing a high elastic limit 

 be regarded as superior. 



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