make the aforesaid needed repairs; provided, however, (B) The Contractor hereby further agrees that all the structures built by him under this contract shall be kept in good and satisfactory condition for the period of one year after the completion of the work to be done under this contract. Should any defects in the work or structures become evident before the expiration of the above guarantee the Contractor shall within five days from the date of the receiving of personal notice or the mailing of a notice by the Engineer to the Contractor proceed to remedy such defects of whatever nature or extent or whenever and wherever found in a proper manner and to the satisfaction of the Engineer and at the expense of the Contractor. In the event of the failure of the Contractor to begin such repairs within the five days above noted (the Owner) that the surety bond attached to and made a part of this contract shall be in full force until the expiration of one year from the date of the payment of the final amount due the Contractor for work done and materials furnished under this contract. CHAPTER XII SPECIFIC CLAUSES In the preparation of the specific or technical clauses, it is well to observe a few simple but important directions, in addition to those given in Chapter V, which the student should review at this point. For the distinction between specific and general clauses see Chapter II. 60. Grouping. It is much easier to refer to these clauses as a whole if they be segregated from the general clauses and preceded by a proper heading. 61. Sequence. As far as is practicable, they should be arranged, for convenience of reference, in chronological sequence (the order in which it is natural to expect the work to be done). This does not, of course, restrict the Contractor to the order observed in the specifications. In some specifications the clauses relating to materials are further segregated from those referring to workmanship. 62. Indefinite Terms. Descriptive terms or units, unless perfectly definite, should be studiously qualified so as to make them definite. (a) For the measurement of masonry, units such as cubic feet or cubic yards would appear to be, and in the case of many engineering structures are, perfectly definite. Certain well established trade rules, varying somewhat locally, affect the measurement of masonry in buildings. Such rules not infrequently provide for the double measurement of corners (or returns), and for the complete or partial disregard of openings (such as doors and windows). Building stone is frequently required to be furnished by the cubic unit. In such cases it should be made clear as to whether ΙΟΙ the measurement is to be based on the volume of each separate stone, or of a heap of stone, or of the finished wall.* (b) As applied to earth, the handling of some of which is necessitated in almost every engineering project, the term "cubic yard" needs qualification, for earth may be and is measured in one of three ways: (i) Before it has been disturbed (in situ), as in railroad grading and similar work.† (ii) In transit, as in a scow on dredging contracts, or in a cart. (iii) In its final resting place, as in certain kinds of filling, for example the reclaiming of marsh land by the hydraulic process. In such cases the date of measurement and other points may need careful attention in the specifications, as some material continues to change volume for a long period of time. (c) The lack of a proper differentiation of earth and rock in the specifications has occasioned a vast amount of unpleasant feeling and of litigation in connection with contract work of a certain character. Geologists make no real distinction between the two. In common parlance earth is soft and rock hard, but these adjectives lose much of their force where there is an almost imperceptible gradation between the two materials in situ. Three methods of classification follow: (i) The distinction most commonly made is that anything requiring blasting for its removal will be estimated as rock. Not infrequently boulders of a certain minimum volume, and tree stumps, both of which it might be possible - though perhaps not economical to remove in some other way, are * Such units as "perch" should never be used by Engineers. A perch of masonry properly contains 24 cubic feet (161⁄2 by 1 by 1). In country districts where it is still in use as a unit a perch of masonry is variously assumed to contain anywhere from 22 to 25 cubic feet of stone. Of interest in this connection is a publication of the Bureau of Standards, Department of Commerce and Labor, Washington, D. C., 1912, entitled State and National Laws Concerning the Weights and Measures of the United States." † The measurement of rock excavation is almost invariably made in situ. classed as rock. In many instances "loose rock" is classified separately.* "No soft, loose or broken rock, impacted boulders or hardpan, but only such solid rock as may be approved by the Engineer in advance as requiring blasting for its removal, and boulders of one half (1) cubic yard or more found in and removed from the excavation, are to be considered as rock excavation." (ii) Another plan for differentiation is based on the possibility of removing the material with a plow. "Dry excavation of rock will include the removal of all ledge rock and hardpan which, in the opinion of the resident Engineer, cannot be plowed, and all boulders measuring one-half a cubic yard or more." (N. Y. State Canals, 1904.) (iii) A recent specification fixes the dividing line between earth and rock at three on the scale of mineral hardness (sometimes called the "Mohs" scale). The student should point out two difficulties apparently involved. "Whenever the word 'rock' occurs in these specifications, it shall be interpreted to mean any material geologically in place and of a hardness when first exposed of three or greater in the scale of mineral hardness, which corresponds to the hardness of the transparent variety of calcite. Other material will not be classed as rock, although it may be more economical to remove the same by blasting." (Chicago Sewers, 1911.) The student should note that certain materials, such as hardpan or quicksand, while properly classed as earth, may in reality be more expensive to excavate than some grades of rock, and further, that it is sometimes advisable to classify earth or rock according to depth of excavation, length of haul, number of times it must be handled, amount of contained moisture, or in other respects. While it is practically impossible to draft a clause covering earth and rock which will be applicable to all local conditions geological and otherwise, painstaking definition in the specifications, and provision for special prices will lead to mutual understanding and often to lower bids. On large and important excavation contracts the expedient of using, as illustrations, samples obtained from borings may * Solid rock has been defined in some specifications as rock which rings when struck with a light hammer. prove to be the only solution of the problem. The Contractor, in such case, bids on the classification as shown by the samples kept on file.* (d) Among other indefinite terms may be noted "a barrel of cement," "parts" (in expressions intending to give the proportions of a concrete or similar mixture), "ton," "ounce," "overhaul," "first (or second or third) class masonry," etc. The student may discuss the uncertainty involved in each of the above terms. Reference to the construction news columns of engineering periodicals will enable the student to familiarize himself with the units in common use for the measurement of different sorts of work. He should prepare a list of the units employed in the measurement of the various parts of the work outlined in Chapter XIII. 63. Stock Articles. where practicable. Specify commercial sizes and patterns Certain sizes of lumber are commonly carried in stock by dealers, while odd sizes must be especially ordered, unless they can be turned out from stock (which may mean a large percentage of waste). Rolling mills make a specialty of certain weights of rolled shapes, the patterns of pipe are becoming somewhat standardized, and in many other departments the Engineer will find that a knowledge on his part of the contents of trade catalogues may effect a saving for his clients. 64. Special Brands. Where possible avoid requiring special brands or patented articles.† (a) Otherwise those who furnish the particular article have a monopoly, and they might take advantage of the situation. Some patented articles are relatively expensive, at best. * It is a simple matter to use such a plan when the necessity arises for defining, for example, an unusual surface finish for concrete or stone masonry. The specifications might in such cases refer with equal propriety either to a prepared sample or to features of an already completed structure. †This rule is not to be regarded as inflexible. Certain articles of standard price are of such excellence that they cannot be duplicated. The requiring of patented or monopolized articles on public work is wholly prohibited by some city charters and state laws; in others the qualification "except in case of absolute necessity" is added, while many contain no reference whatever to the matter. (See Art. 45.) |