From Engineering and Contracting, 1909. ]
=126. Specifications.=—The following abstracts have been taken from the specifications on Excavation by the Baltimore Sewerage Commission as illustrative of good practice. In conducting the work the contractor shall:
... remove all paving, or grub and clear the surface over the trench, whenever it may be necessary and shall remove all surface materials of whatever nature or kind. He shall properly classify the materials removed, separating them as required by the Engineer; and shall properly store, guard, and preserve such as may be required for future use in backfilling, surfacing, repaving or otherwise. All macadam material removed shall be separated and graded into such sizes as the Engineer may direct and materials of different sizes shall be kept separate from each other and from any and all other materials.
All the curb, gutter, and flag-stones and all paving material which may be removed, together with all rock, earth and sand taken from the trenches shall be stored in such parts of the carriageway or such other suitable place, and in such manner as the Engineer may approve. The Contractor shall be responsible for the loss of or damage to curb, gutter and flag-stones and to paving material because of careless removal or wasteful storage, disposal, or use of the same.
... When so directed by the Engineer the bottom of the trench shall be excavated to the exact form of the lower half of the sewer or of the foundation under the sewer.
The bottom width of the trench for a brick or concrete sewer shall be ... not less in any case than the overall width of the sewer, as shown on the plans. In case the trench is sheeted this minimum width will be measured between the interior faces of the sheeting as driven, but in no case shall bracing, stringers, or waling strips be left within any portion of the masonry of the sewer except by permission of the Engineer; and such braces, stringers and waling strips shall not, in any case, be allowed to remain within the neat lines of the masonry as shown on the plans. In case that the distance between faces of the sheeting is less than that called for by the width of the sewer to be laid in the trench, the Engineer may direct the sheeting to be drawn and redriven, or otherwise changed and altered; or he may direct that the sewer be reinforced in such manner and to such an extent as he may deem necessary without compensation to the Contractor, even though such narrower trench was not caused by negligence or other fault on the part of the Contractor.