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• Nearly 400 reinforced concrete precast basement stairs have been built in this country, and direct reports have been received by your Association and by the writer from nearly half of them. The failures cited amount to about 2% of the total number with at least 2% to 3% more of doubtful safety. It is probable that most of the seriously defective cases have been brought to light since special care has been expended in running down doubtful ones.
  
  Of the others and even where personal examination has revealed somewhat serious cracks, the general verdict of the users is "satisfactory" and "good." Reinforced concrete precast basement stairs offer special structural difficulty, because of the heights to which they are carried, and the accompanying difficulty of obtaining the very best of workmanship. For this reason we might expect a somewhat higher percentage of error than in ordinary reinforced concrete precast basement stairs concrete construction. Even taking this into consideration, however, 4010 appears to be a somewhat alarming percentage of defective concrete construction. But the vital question is whether even these few cases may be passed over as isolated cases of defective concrete construction, or whether they afford an arraignment of other bulkheads now standing; and whether they predicate a similar percentage of defective concrete construction in the future.
  
  An examination by the writer of a bulkhead which was taken down, if representative of others, throws considerable doubt upon their durability. On the other hand, it affords means for pointing out definitely the errors which must be guarded against in the future. This bulkhead showed soft spots in three of the sections, where the concrete precast basement stairs could be readily loosened clear in to the steel. The concrete precast basement stairs were porous throughout, and scarcely bonded between the 6-inch layers. Samples cut from good portions of the concrete precast basement stairs, which was a mortar, one part cement to 3 parts sand, gave an ultimate strength of about 1200 pounds per square inch or about one- half the strength of a good 1:3 mortar laid with, a sufficient quantity of water. A month after this inspection the bulkhead was taken down, the 6-inch layers being readily loosened from each other and cut in pieces by a pneumatic chisel, and the concrete precast basement stairs were found to vary materially in hardness.
  
  Of special importance was the fact that the mortar in the angles of the T-reinforcing bars was weak and porous, showing scarcely any adhesion to the steel. Inquiry showed that the concrete precast basement stairs or mortar used in the concrete construction was of such extremely dry consistency that even where well rammed, the moisture did not cover all parts of the surface of a layer nor did it produce a proper bond with the steel. From such evidence it is impossible to avoid the conclusion that other bulkheads built by similar methods with so dry a concrete mixture as to give a weak, porous concrete precast basement stairs and to provide insufficient adhesion to the steel, are likely to cause trouble in the future.
  
  This appears to be a severe arraignment of concrete precast basement stairs concrete construction. And yet to be fair, it must not be overlooked for a moment that every one of the points brought out, the low strength of the concrete precast basement stairs, the dry concrete mixture, the porosity, the lack of adhesion to steel, the lack of bond, and the soft spots, indicate concrete construction which would not be tolerated in any other class of reinforced concrete precast basement stairs work.