NOTE: The thickness of beds in dimensioned masonry may vary from 3-inch to 1-inch from the bottom to the top of the work, but in each course the beds shall be of uniform thickness throughout.

Unless shown otherwise on the plans, beds shall not extend in an unbroken line through more than 5 stones, and joints through more than 2 stones.

Joints in dimensioned masonry shall be vertical. In all other masonry, joints may be at angles with the vertical from 0 to 45 degrees.

Each face stone shall bond with all contiguous face stones at least 6 inches longitudinally and 2 inches vertically.

At no place shall corners of four stones be adjacent to each other.

Cross beds for vertical walls shall be level and for battered walls may vary from level to normal to the batter line of the face of the wall. All arch ring joints shall be completely filled with mortar.

610.13 Headers. When headers are required they shall be distributed uniformly throughout the walls of structures so as to form at least one-fifth of the faces.

610.14 Backing. The backing shall be built chiefly of large stones and in a workmanlike manner. The individual stones composing the backing and hearting shall be well bonded with the stones in the face wall and with each other. All openings and interstices in the backing shall be filled completely with mortar or with spalls surrounded completely by mortar.

610.15 Coping. Copings, if called for, shall be as shown on the plans. Where copings are not called for, the top of the wall shall be finished with stones wide enough to cover the top of the wall, from 12 to 5 feet in length, and of random heights, with a minimum height of 6 inches. Stones shall be laid in such a manner that the top course is an integral part of the wall. The tops of the top courses of stone shall be pitched to line in both vertical and horizontal planes.

610.16 Parapet Walls. Selected stones, squared and pitched to line and with heads dressed, shall be used in ends of parapet walls and in all exposed angles and corners. Headers shall be well interlocked and as many as possible shall extend entirely through the wall. Both the headers and stretchers in the two faces of the wall shall be well interlocked in the heart and shall comprise practically the whole volume of the wall. All interstices in the wall shall be completely filled with cement grout or with spalls completely surrounded with mortar or grout.

610.17 Facing for Concrete. Unless otherwise specified, the stone masonry shall be constructed before placing concrete. When provided for in the special provisions or upon the approval of the Engineer, the concrete may be placed before constructing the stone masonry. (a) Stone masonry constructed prior to placing concrete.-Hooked steel anchors consisting of No. 4 bars each bent into an elongated letter S shall be spaced 2 feet apart both horizontally and vertically unless closer spacing is shown on the plans or ordered in writing by the Engineer. To improve the bond between the stone masonry and the concrete backing, the back of the former shall be made as uneven as the stones will permit. Each anchor shall be rigidly embedded in a horizontal joint of the masonry with one end 2 inches from the faces of the stones. The other end shall project approximately 10 inches into the concrete backing. When the stone facing has been laid and the mortar has attained sufficient strength, all surfaces against which concrete is to be placed shall be cleaned carefully and all dirt, loose material, and accumulations of mortar droppings removed. 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 the surface of the masonry shall be cleaned using wire brushes and acid.

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 the work has been completed.

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. One-half 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 554. No direct payment will be made for metal slots, anchors, or other devices placed in accordance with subsection 610.17(b).

611.01 This work shall consist of furnishing and installing horizontal drains and a collector system in accordance with these specifications and in reasonably close conformity with the lines and grades shown on the plans or established by the Engineer.

Materials

611.02 (a) Horizontal drains. The type of pipe and fittings to be furnished shall be selected from one of the following:

(1) Slot-perforated, standard weight, galvanized steel or black iron or steel pipe and nonperforated, standard weight, galvanized steel pipe.

(2) Slot-perforated, schedule 80, PVC pipe and non-perforated, standard weight, galvanized steel pipe.

(3) Slot-perforated and non-perforated, schedule 80, PVC pipe.

The slot-perforated steel pipe shall be furnished without threads or couplings. The entrance end of the pipe shall be cut, shaped and welded for steel, or cemented or plugged for

PVC, to form a rough point and shall be closed to prevent the entrance of foreign material. The pipe shall conform to the Federal Specifications WW-P-404 for steel pipe and L-P-320 for PVC pipe.

The slot-perforations shall be as shown in the contract.

Non-perforated pipe, approximately 6 to 12 feet in length, shall be provided at the mouth of the drain. The exact length will be determined by the Engineer.

(b) Collector system. Elbows, tees, corrugated metal pipe, PVC pipe, and other accessories shall be furnished to construct a collector system as shown on the plans.

Collector pipe shall be either corrugated galvanized metal pipe or PVC pipe. The pipe and accessory materials shall conform to the requirements of Federal Specifications WW-P-405 and L-P-320. All joints shall be water tight.

Plastic pipe for the outlet shall be PE 3306, Schedule 40, conforming to ASTM D 2447.

Construction Requirements

611.03 Drilling Operations. Holes shall be drilled to the line and grade shown on the plans or as directed by the Engineer. The locations for horizontal drains shown on the plans are approximate only and the exact locations shall be as directed by the Engineer.

Holes shall be drilled with rotary equipment capable of drilling 3-inch to 6-inch diameter holes up to 300 feet in length to the designated lines and grades through soil and rock formations.

Water used for drilling and water developed during drilling operations shall be disposed of by the Contractor in such a manner that no damage will result to the work.

Following completion of the drilling operation, the Contractor shall determine the elevation at the upper end of the completed horizontal drain hole. The measurements may be made by inserting tubes or pipes and measuring liquid levels, or by other means satisfactory to the Engineer.

611.04 Installing Horizontal Drain Pipe. Where the Engineer determines that the installation of the horizontal drains in a drilled hole will be ineffective, no drain pipe shall be installed.

Drain pipe shall be installed by inserting the pipe inside the drill rod and then retracting the drill rod so that the drilled hole is then cased with the drain pipe for the full length of the drilled hole. The upper end of the drain pipe shall be tightly plugged with a rounded or pointed extension which shall not extend more than 0.5 foot beyond the end of the pipe. The installation of the drain pipe shall be done in such a manner that the drain pipe will be connected where necessary to form a continuous tube. Telescoping is not permitted.

Slotted pipe shall be used within 3 to 5 feet of the outlet end. Unslotted drain pipe shall be used for the last 3 to 5 feet of the outlet end and the space between the drilled hole and the drain pipe shall be tightly sealed for a length of at least 3 feet at the outlet end of the hole. 611.05 Installing Outlet Pipe. Outlet drain pipe shall be attached to the ends of all horizontal drains by means of a tee, plug, or street ell. The length of the outlet pipe shall be varied as required and as shown on the plans.

Method of Measurement

611.06 Horizontal drains will be measured by the linear foot for furnishing and installing drain pipe and by the linear foot for drilling holes.

The quantity of drain pipe will include the length of pipe installed regardless of whether slot-perforated pipe or non-perforated pipe is used, including the length of the pipe at outlet end required to connect to collector system.

The quantity of holes drilled will include the length of hole drilled with drain pipe installed. If a hole is drilled and the Engineer determines the drain pipe is not to be installed, the quantity for drilling holes will include 50 percent of the length of the hole drilled. The collector system will be measured by the linear foot, furnished and installed.

Basis of payment

611.07 The quantities, determined as provided above, will be paid for at the contract unit price per unit of measurement for each of the pay items listed below, which prices and payments will be full compensation for furnishing and placing all material, including all water required for drilling holes, and necessary tees, plugs, elbows and other attachments required for construction of, and connection to the collector system, and for all labor, tools, equipment, and other incidentals necessary to complete the work prescribed in this section.

613.01 This work shall consist of Reinforced Earth* walls constructed in accordance with these specifications and in reasonably close conformity with the lines, grades, design, and dimensions shown on the plans or established by the Engineer.

Materials

613.02 General. The Contractor shall make his own arrangements to purchase the face panels, reinforcing and tie strips, fasteners, joint filler, and all necessary attachments from sources listed in the contract documents.

(a) Concrete Face Panels. Cement shall conform to AASHTO M 85. Concrete shall have a minimum compressive strength at 28 days of 4000 psi. Air entraining, retarding or accelerating agents or any additive containing chloride shall not be used without approval of the Engineer.

Tie strips, connecting pins, and PVC tubes and lifting and handling devices shall be set in place to the dimensions and tolerances shown on the plans prior to casting.

(1) Testing and Inspection. Acceptability of the precast units will be determined on the basis of compression tests and visual inspection. The Contractor or his supplier shall furnish facilities and perform all necessary sampling and testing in an expeditious and satisfactory manner. Panels at the option of the Engineer shall be acceptable for placement in the wall when 7-day strengths exceed 65 percent of 28-day requirements.

(2) Casting. The panels shall be cast on a flat area, the front face of the form at the bottom, the back face at the upper part. Tie strip guides shall be set on the rear face. The concrete in each unit shall be placed without interruption and shall be consolidated by the use of an approved vibrator, supplemented by such hand-tamping as may be necessary to force the concrete into the corners of the forms and prevent the formation of stone pocket or cleavage planes. Clear form oil of the same manufacture shall be used throughout the casting operation.

(3) Curing. The units shall be cured for a sufficient length of time so that the concrete will develop the specified compressive strength.

(4) Removal of Forms. The forms shall remain in place until they can be removed without damage to the unit.

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