Picks, scrapers, and wire brooms shall be used for this purpose if necessary. If compressed air is available on the work, it shall be used to blow out the dust and dirt. Just before the concrete is placed, the surfaces shall be washed thoroughly. Water shall be dashed forcibly against the stones and into the joints. Use of a stream from a hose is preferable for this purpose. In depositing concrete, the top surface immediately adjacent to the stones shall be held slightly low and a neat cement grout of the consistency of cream shall be carried on top of the concrete and against the masonry at all times, so that the entire exposed areas of all the stones are coated with grout. All interstices of the masonry shall be filled and the concrete thoroughly spaded and worked until it is brought into intimate contact with every part of the back of the

masonry.

(b) Concrete placed before constructing masonry.—Except where otherwise shown on the plans, a thickness of 9 inches shall be allowed for facing. Galvanized metal slots with anchors for the stone work, or other approved type of metal anchor, shall be set vertically in the concrete face at a horizontal spacing of not to exceed 24 inches. The slots shall have a temporary filling of felt or other material to prevent them from being filled with concrete. During the setting of the stone facing, the metal anchors shall be fitted tightly in the slots at an average vertical spacing of 24 inches. The Engineer will mark on the concrete backing the approximate location of the anchors, and the anchor shall be placed in the stone joint nearest to the mark. At least 25 percent of the metal anchors shall have a short right-angle bend to engage a recess to be cut into the stone. The anchors shall extend to within 3 inches of the exposed face of the stone work. Where the shape of the concrete face is unsuitable for the use of metal slots, ties consisting of U.S. Standard Gage No. 9 galvanized iron wire shall be placed as directed by the Engineer, but there shall be not less than one wire tie for each 1.5 square feet of exposed stone surface. In laying the stone, the concrete face shall be kept wet continuously for 2 hours preceding the placing of the stone, and all spaces between the stone and concrete shall be thoroughly filled with mortar. Immediately after laying, all exposed stone surfaces shall be cleaned and kept clean of loose mortar and cement stains.

610.18 Pointing. The pointing or finishing of all joints shall be as shown on the plans or as specified in the special provisions.

When raked joints are called for, all mortar in exposed face joints and beds shall be raked out squarely to the depth noted on the plans. Stone faces in the joints shall be cleaned free of mortar.

When weather joints are called for, the beds shall be weather struck. The joints shall be slightly raked to conform to the bed weather joint and in no case shall the mortar be flush with the faces of the stones.

The mortar in joints on top surfaces shall be crowned slightly at the center of the masonry to provide drainage. 610.19 Weep Holes. All walls and abutments shall be provided with weep holes. Unless otherwise shown on the plans or directed by the Engineer, the weep holes shall be placed at the lowest points where free outlets can be obtained and shall be spaced not more than 10 feet center to center.

610.20 Cleaning Exposed Faces. Immediately after being laid, and while the mortar is fresh, all face stone shall be thoroughly cleaned of mortar stains and shall be kept clean until the work is completed. Before final acceptance and if ordered by the Engineer, the surface of the masonry shall be cleaned using wire brushes and acid if necessary.

610.21 Weather Limitations. Placing of stone shall not be done in freezing weather except by written permission from the Engineer and then only by the use of such precautionary methods as he may prescribe for doing the work and protecting it at all times. Such permission and the use of the methods prescribed will not, however, release the Contractor from his obligation to build a satisfactory structure. All work damaged by cold weather shall be removed and replaced. In hot or dry weather the masonry shall be satisfactorily protected from the sun and shall be kept wet for a period of at least 3 days after completion.

Method of Measurement

610.22 Stone masonry. The quantity to be paid for will be the number of cubic yards of stone masonry of the various classes, complete in place and accepted. When shown as a separate pay item in the bid schedule, separate measurement will be made for that portion of any class of masonry contained in a specifically designated part of the structure. Measurement will not include sample sections of wall, unless permitted to be incorporated in the work.

In computing the yardage for payment, the dimensions used will be those determined by the payment lines or payment volumes shown on the plans or ordered in writing by the Engineer. The computed volumes will not include any concrete or stone masonry paid for under any other item. Onehalf the volume of the mortar joint between different classes of stone masonry will be included in the measurement for each adjoining class of masonry. The projections of face stones extending beyond the pitch lines will not be included.

The volumes of stones labeled on the plans as "cap stones" will be their actual volumes. No deductions will be made for weep holes, drain pipe, or other openings of less than 2 square feet in area, or for chamfers or other ornamental cuts that amount to 5 percent or less of the volume of the stone in which they occur.

610.23 Other Items. The quantities of concrete, reinforcing steel, and other contract items which constitute the completed and accepted structure will be measured for payment in the manner prescribed for the several items involved.

Basis of Payment

610.24 The quantity, determined as provided above, will be paid for at the contract price per unit of measurement, respectively, for each of the particular pay items listed below that is shown in the bid schedule, which price and payment will be full compensation for all work included in this section except furnishing and placing steel S-bar anchors, which will be measured and paid for under section 602. No direct payment will be made for metal slots, anchors, or other devices placed in accordance with subsection 610.17(b). Payment will be made under:

When more than one pay item is specified for one class of stone masonry, letter suffixes will be added to the item number and identification inserted in parentheses after the pay name.

Section 611.-STEEL STRUCTURES

Description

611.01 This work shall consist of steel structures and the steel structure portions of composite structures, constructed in reasonably close conformity with the lines, grades, and dimensions shown on the plans or established by the Engi

neer.

The work will include the furnishing, fabricating, erecting,

and painting of structural metals called for in the special provisions or shown on the plans. Structural metals will include structural, rivet, welding, special, and alloy steels, metallic electrodes, steel forgings and castings, and iron castings. This work will also include any incidental metal construction not otherwise provided for, all in accordance with these specifications, plans and special provisions.

Construction Requirements

611.03 Shop Inspection. The contractor shall give the Engineer ample notice of the beginning of work at the mill or in the shop, so that inspection may be provided. The term "mill” means any rolling mill or foundry where material for the work is to be manufactured. No material shall be manufactured or work done in the shop before the Engineer has been so notified.

The Contractor shall furnish the Engineer with as many copies of mill orders as the Engineer may direct.

611.04 Fabrication:

General.-Riveted construction shall be followed except where welded or bolted construction is indicated on the plans or in the special provisions. The Contractor may, however with approval of the Engineer, substitute high tensile

strength steel bolts equivalent to the rivets in any connection.

Workmanship and finish shall be in accordance with the best general practice in modern bridge shops. Portions of the work exposed to view shall be finished neatly. Shearing, flame cutting, and chipping shall be done carefully and accurately. Structural material, either plain or fabricated, shall be stored at the bridge shop above the ground upon platforms, skids, or other supports. It shall be kept free from dirt, grease, or other foreign matter, and shall be protected as far as practicable from corrosion.

Rolled material, before being laid off or worked, must be straight. If straightening is necessary, it shall be done by methods that will not injure the metal. Sharp kinks and bends will be cause for rejection of the material.

Steel or wrought iron may be flame cut, provided a smooth surface free from cracks and notches is secured and provided that an accurate profile is secured by the use of a mechanical guide. Free-hand flame cutting shall be done only where approved by the Engineer. The cutting flame shall be so adjusted and manipulated as to avoid cutting beyond (inside) the prescribed lines. Members with excessive cracking or cracks of depth exceeding 3/16 inch will not be acceptable. Flame cut surfaces shall meet the USASI surface roughness rating value of 1,000 for material 4 inches or less in thickness and 2,000 for material greater than 4 inches in thickness. Edges shall have their corners rounded to 1/16inch radius by grinding after flame cutting.

Re-entrant cuts shall be filleted to a radius of not less than 4 inch. Occasional notches, cracks and surface roughness, not more than 3/16 inch deep on otherwise satisfactory cut surfaces, may be removed by planing or grinding. Defects of flame cut edges shall not be repaired by welding except with the express approval of the Engineer for occasional notches or gouges less than 3/8 inch deep in types of steel considered weldable in the "Specifications for Welded Highway and Railway Bridges" of the AWS. Such weld repair shall be made by suitably preparing the defect, welding with low hydrogen electrodes not exceeding 5/32 inch in diameter, observing the applicable requirements of subsection 611.12 and grinding the completed weld smooth and flush with the adjacent surface to produce a workmanlike finish. Corrections of the defects must be faired with the surfaces of the cuts on a bevel of 1 to 6 or less.

At least one bend test shall be made of flame cut edges to qualify the procedures and workmanship for each grade of steel used for main members, in the greatest thickness of each grade to be flame cut on the finished edges in manu