Under these items the Contractor shall provide the system of drains shown on the plans or ordered.

Excavation. - All excavations shall be made in open trenches unless otherwise ordered. No tunneling will be allowed except by written permission or order obtained from the Engineer prior to the commencing of the work in tunnel, and the right is reserved to countermand this order or permit at any time during the progress of the work.

The Contractor must assume the risk of encountering quicksand, hardpan, rock, rubbish, unforeseen obstacles, etc., in his excavation, and no claim for payment other than the price bid per lineal foot will be allowed on account of the character of the ground in which the excavations are made.

Where rock is encountered, the Contractor shall excavate to a depth of six inches below grade, and shall fill the trench to grade with gravel or other acceptable material. The compensation for the material thus removed will be included in and paid for at the price bid per lineal foot.

The width of the excavation shall be six (6) inches greater on each side than the extreme outside diameter of the drains.

Unauthorized Excavation. - So far as the nature of the ground will admit, the bottom of the excavation shall have the shape and dimensions of the outside lower half of the drain pipe. If the trench is excavated below the limits thus prescribed, the Contractor shall, at his own expense refill this space to the proper grade with concrete or other suitable material, as directed.

Extra Excavation and Refill. - If the character of the excavation is deemed unsuitable for a foundation, the Contractor shall excavate below the bottom of the drain to the extent required and other material satisfactory to the Engineer shall be deposited in its place. If the price for such additional excavation and refill is not included in the schedule, the price shall be determined as provided for in these specifications.

Sheeting and Bracing. - For the protection of the work and adjacent property the Contractor shall furnish, place and maintain at his own expense suitable sheeting and bracing in the trench. Additional sheeting or bracing shall be placed at the expense of the Contractor, if deemed necessary, and the compliance with such orders shall not relieve or release the Contractor from his responsibility for the sufficiency of such support.

Sheeting and bracing may be left in place in the trench at the option of the Contractor unless otherwise ordered by the Engineer. When sheeting is left in place it must be cut off at an elevation at least three feet below the surface of the street unless otherwise permitted.

The Engineer may order sheeting and bracing left in place when deemed necessary for the protection of the drain. In such cases only, a charge will be allowed for the same at a rate of twenty ($20.00) dollars per thousand feet B. M.

Protection of Pipes, etc. - In addition to the necessary sheeting and bracing of the trench all pipes or conduits encountered in the trench shall be carefully supported, protected, and if injured shall be repaired and replaced as directed, and at the expense of the Contractor.

Where it is necessary to alter the alignment or dimensions of a drain because of sub-surface condition, such change shall be made by direction of the Engineer, and without extra cost to the City.

Trench Open. - The length of trench open at any one time shall be controlled by the use of the street or way by the public, but shall always be confined to the limits prescribed by the Engineer.

Pumping, Draining, etc - The Contractor shall do all pumping, bailing, draining, or other work necessary to keep the trench clear of all water regardless of its source, ground water, sewage or storm water, during the progress of the work and until the cement mortar is sufficiently set to be safe from injury.

Whenever deemed necessary under-drains shall be laid for the purpose of draining the trenches during construction. These pipes shall be laid with open joints entirely surrounded by gravel or broken stone and at a depth below the main drain, as directed by the Engineer. If the price for such. under-drain is not included in the schedule, the price shall be determined as provided for in these specifications.

Surplus Excavation. - All surplus materials excavated from the trench shall be removed from the ground as the work progresses or shall be deposited in other places along the line of work as directed.

Pipe. - All pipe and specials shall be of the best quality salt-glazed vitrified clay sewer pipe of the hub and spigot pattern. The pipe shall be free from cracks, warps, fire cracks, blisters, and other serious imperfections.

Each pipe shall have a socket of sufficient diameter to receive the spigot of the next following pipe without any chipping of either pipe, and shall have a clearance all around for the purpose of a joint of at least one-half (1/2) inch.

Double strength pipe shall be used. Both body and hub shall have a thickness not less than one-twelfth (1-12) inside diameter of the pipe. The depth of the hub shall be at least one and one-half (1 1/2) inches greater than the required thickness of the pipe.

All pipe will be inspected upon delivery and those which do not conform to the requirements of these specifications will be rejected and shall be immediately removed by the Contractor.

Pipe Laying. - Each pipe shall be laid on a firm bed in conformity to the lines and grades given, and shall form a close joint with the next adjoining pipe. The trench shall be carefully prepared so that the pipe shall rest uniformly for the length of the barrel and ample room shall be made at the sides and below the bells to allow first-class work being done in jointing the pipes. The joints shall be made with a gasket of jute or hemp and Portland Cement mortar, the mortar being mixed in the proportion of one part cement to one part sand. The gasket shall be soaked in a mixture of neat Portland Cement and water and then inserted between the bell and spigot and carefully caulked into place. The remainder of the joints shall be filled with cement mortar applied with the hands, well pressed and caulked into place, after which the joint shall be leveled off with mortar for a distance of two inches from the outer edge of the bell. The joint shall be wrapped in unbleached cotton cloth, securely tied to prevent the mortar from slipping or being otherwise injured. The inside of the pipe shall be satisfactorily cleaned of all surplus mortar or other foreign substances.

Pipe must be laid in a "dry trench; no work shall be done in freezing weather, except where permitted by the Engineer, and in the manner specified by him.

Pipe shall be laid only in the presence of the Inspector.

Branch pipes shall be provided and laid where and as directed. The open ends of pipe and branches shall be sealed with stoneware stoppers, cemented into place in an acceptable manner.

Backfilling or Filling. - Backfilling around the drain shall be done very carefully to insure an even and continuous support to the bottom and sides, a special tamping iron being provided by the Contractor for this purpose. No walking on the drain after it is laid will be permitted until it is covered with earth, thoroughly tamped to a depth of 12 inches above the top of the drain.

Above this point the earth shall be deposited in the trench in layers not over six (6) inches in depth. Each layer will be carefully leveled off and worked into the inequalities in the sides of the trench and will' then be thoroughly tamped. After the completion of the backfilling to the sub-grade of the street the trench' will be thoroughly flushed with water.

Wherever the sewer is constructed in tunnel, the Contractor shall refill the space between the drain and the sides of the tunnel with sand, gravel or concrete thoroughly rammed into place, unless otherwise directed by the Engineer. The cost of such work shall be included in the price bid.

In places where the drain projects above the natural surface of the ground, the drain shall be covered with earth to a depth of not less than three feet. Where the trenches do not furnish sufficient material the Contractor shall supply such deficiency at his own expense. Such filling shall1 be placed and tamped as described hereunder for "Backfilling."

Measurements. - Payments will be based on horizontal center line measurements. The interior diameter of special structures and four (4) feet for each manhole will be deducted from the gross length of drain.

Payment. - Unless otherwise specified, the price bid for drains per lineal foot shall include excavating, sheeting and bracing, all pumping, bailing, draining, the furnishing of all materials and the placing or removal of same, and backfilling or refilling.