570STONE MASONRY

New Hampshire Department of Transportation Standard Specifications – 2016 Description

1.1This work shall consist of furnishing all materials and constructing masonry of approved stones, laid with or without cement

mortar, as shown on the plans or ordered. Materials

2.1Stone shall be furnished in accordance with Table 570-1.

Table 570-l - Stone for Stone Masonry Finish

Stone

Source

Quality

Dress and Cut Top and Bottom Vertical Face Joints Ashlar approved quarry having the required quantity compact, hard and practically non-absorbent; texture and color as indicated on plans or ordered to exact dimensions fine fine Squared approved quarry having the required quantity compact, hard and practically non-absorbent; texture and color as indicated on plans or ordered roughly squared and to approximate dimensions rough for at least 12” depth rough for at least 9” depth Rubble field, quarry, or rock excavation approved, sound, clean, and free from structural defects unsquared, roughly dressed --- ---

2.1.1 Ashlar and Squared Stone. 2.1.1.1 Stones shall have their edges pitched to a true line with tops and bottoms parallel and cut to lie on their natural beds. The bottom beds shall be the full size of the stone, and hollow beds or overhanging tops will not be permitted. 2.1.1.2 When specified as random or broken-ranged, stone shall have vertical joints unless otherwise indicated on the plans. 2.1.1.3 Size of stone shall be as indicated on the plans. 2.1.1.4 Surface finish shall be as shown on the plans in accordance with the following schedule:

more than 1-1/4”

appearance

2.1.1.5 All stone shall be so finished that no holes or portions of holes will show on surfaces which will be exposed in the finished work.

2.2Cement mortar shall conform to Section 707.

2.3Stone masonry anchors shall be of the shapes and dimensions shown on the plans. The minimum ultimate tensile strength

shall be 42,000 psi. Anchors shall be zinc-coated (galvanized) in accordance with ASTM A 653, coating designation G 90. Construction Requirements

3.1Classification.

3.1.1 Stone masonry shall be classified by pattern: ranged, broken ranged, or random.

New Hampshire Department of Transportation Standard Specifications – 2016

courses is varied, it shall be regularly diminished from bottom to top masonry.

3.1.2 Stone masonry shall be classified by type of stone and thickness of joints, in accordance with Table 570 -2.

3.2Laying Stone.

3.2.1 All shaping and dressing of stone shall be done before it is placed. 3.2.2 When required, the Contractor shall submit details of falsework or centering for approval. 3.2.3 No stone in broken-ranged or random work shall be laid in a structure until at least 50 percent of the amount required for the structure has been delivered at the site. 3.2.4 Stone shall be carefully set without jarring stone already laid and shall be handled with a lewis or other suitable device which will not mar the stone. Rolling or turning of stone on masonry already in place will not be permitted. Table 570-2 - Stone Masonry Classification Class of Masonry Type of Stone Joint Material Max. Thickness Ashlar Ashlar Cement mortar 1/2 Mortar Squared Stone Squared Cement mortar 1 Dry Squared Stone Squared Dry (closely and lightly pinned) ----- Mortar Rubble Rubble Cement mortar 1-1/2 Dry Rubble Rubble Dry (closely and lightly pinned) ----- Copings Squared (Sawn Finish) Cement mortar 1/2 3.2.5 Stone to be laid in cement mortar shall be thoroughly cleaned before being set, and the bed to receive it shall be well cleaned. The thickness of all joints and beds shall be uniform throughout. Spalls shall not be used as pinners in mortar be ds or joints. When any stone is disturbed or mortar joint broken, the stone shall be taken up, and after all mortar has been cleaned from the stone, bed, and joints, it shall be reset in fresh mortar. 3.2.6 All stones shall be well bedded with the face joints properly pointed before the mortar has set, unless otherwise permitted. When permitted, joints to be pointed after mortar has set shall be raked out to a depth of 2 ” before mortar has set and when pointed, shall be moistened and filled with mortar well driven in. All pointing shall be finished with an approved poin ting tool to form the type of joint indicated on the plans or ordered. 3.2.7 The masonry shall be kept wet during the pointing and in hot or dry weather shall be protected from the sun and kept wet for a period of 3 days after completion unless otherwise permitted or ordered. The exposed surfaces of the stones shall not be smeared with mortar. The joints shall be wiped free of loose mortar. Stone shall not be set when containing frost or during freezing weather unless permitted. When permission is granted, the masonry shall be protected in the same manner as concrete in 520.3.7 except that liquid curing compound shall not be used, and the masonry temperature shall be controlled as provided in 520.3.7.4.7 .

3.3Bond.

3.3.1 Stretchers shall have a depth of bed of not less than 1-1/2 times their height. They shall have a length not less than their height, nor less than 3 ft., nor more than 3-1/2 times their height, unless otherwise indicated on the plans. 3.3.2 Headers shall have a length of 1-1/2 times their height and shall extend entirely through masonry having a thickness of 4 ft. or less. In masonry having a thickness greater than 4 ft., the depth of headers shall not be less than 2 -1/2 times their heig ht when the course is 18” or less in height, and not less than 4 ft. in courses of greater height. Headers shall hold into the heart of the wall the same size shown on the face, bonding not less than 12 ” with the core or backing. Headers shall be placed over stretchers equally dividing the spaces between headers of adjoining courses with no joints coming immediately over or under headers. Headers shall be spaced not more than 8 ft. apart, and there shall be at least 1 header to every 2 stretchers unless otherwise indicated on the plans.

3.4Copings. Stone for copings shall be selected. Copings shall be as shown on the plans.

3.5Cores and backing. Cores or backing shall be of stone or concrete masonry as indicated on the plans.

New Hampshire Department of Transportation Standard Specifications – 2016 3.5.1 Stone backing shall be laid as specified for face stone, with headers interlocking with face headers when the thickness of the masonry permits. Stone in backing or cores shall break joints with the face stone and bond not less than 12” with the face stone and with each other. Stone backing or cores shall be carried up with face stone and at least 50 percent of the stone shall be of the same size and character as the face stone and shall have parallel ends. When stone is laid in cement mortar, the beds shall be full and shall not exceed 1” in thickness, and the joints shall be completely filled and shall not exceed 4” in thickness. 3.5.2 Concrete backing or cores shall be of the class shown on the plans and as specified in 520. The concrete shall be so worked and compacted that all spaces around stones are completely filled and an adequate bond with the stone is secured. Construction joints in the concrete, required by intermittent placing, shall be located not less than 6 ” below the top bed of any course of the stone facing. The concrete shall be so placed that the stone masonry facing is not disturbed.

3.6Metal dowels and cramps. Dowels and cramps shall be of the material, size, and shape, and at the locations indicated on

the plans or as ordered. Holes for dowels or cramps shall be drilled in the stones before they are placed unless otherwise permitted. Cramps shall be countersunk flush with the top of the stone in which they are set. This work shall be subsidiary.

3.7Culvert headwalls and retaining walls. In addition to applicable construction requirements, unless otherwise specified on

the plans or in the special provisions, culvert headwalls and retaining walls to be constructed of mortar rubble masonry or d ry rubble masonry shall conform to the following requir ements: At least 75 percent of the stone shall be larger than 6 by 9 by 12 ” No dressing, finishing, or coursing will be required. The stone shall be set without disturbing stone already in place. Sto ne to be laid in mortar shall be clean and moist and s hall be placed on a full mortar bed. The stones shall be bonded in a workmanlike manner.

3.8Weepers. Unless otherwise indicated on the plans, the Contractor shall furnish and place 4” weepers in all closed abutments

and retaining walls. These weeperss hall be approximately 10 ft. apart and placed at the elevation which will best drain backfill. French drains of stone or coarse gravel shall be placed adjacent to the fill face of such walls and at such elevations as wil l permit drainage to and outletting into the weepers.

3.9Stone Masonry Arches.

3.9.1 Masonry for rings shall be ashlar or mortar squared stone unless otherwise indicated on the plans. Voussoirs shall be full size and shall have a bond of not less than the depth of the stones. Their beds shall be dressed to bring them to radial planes and to permit them to rest properly on the centering. The inside faces of stone backing or spandrel walls and extrados shall be given a finishing coat of 1:2-1/2 cement mortar troweled smooth, and waterproofed as indicated on the plans. 3.9.2 Masonry in arch rings shall be placed in such a manner as to load the ring uniformly about the center or as indicated on the plans. Method of Measurement

4.1Stone masonry, of the class specified, except coping and resetting masonry wall will not be measured, but shall be the cubic

yard final pay quantity in accordance with 109.11 for stone masonry required as shown on the plans.

4.2Stone coping will not be measured, but shall be the linear foot final pay quantity in accordance with 109.11 for stone coping

required as shown on the plans.

4.3Resetting masonry wall will be measured by the cubic yard , to the nearest 0.1 of a cubic yard.

Basis of Payment

5.1Stone masonry, of the class specified, except coping and resetting masonry wall,, are final pay quantity items and will be

paid for at the Contract unit price per cubic yard complete in place in accordance with 109.11 , with the exception that masonry steps including the parapet walls will be paid for at 1.5 times the Contract unit price per cubic yard for the class specified.

5.2Stone coping is a final pay quantity item and will be paid for at the Contract un it price per linear foot complete in place in

accordance with 109.11.

5.3The accepted quantity of resetting masonry wall will be paid for at the Contract unit price per cubic yard complete in place.

Pay items and units:

570.1Ashlar Masonry (F) Cubic Yard

570.2Mortar Squared Stone Masonry (F) Cubic Yard

570.3Dry Squared Stone Masonry (F) Cubic Yard

570.4Mortar Rubble Masonry (F) Cubic Yard

570.5Dry Rubble Masonry (F) Cubic Yard

570.6Stone Coping (F) Linear Foot

570.9Resetting Masonry Wall Cubic Yard

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This work shall consist of reconstructing stone walls where shown on the plans or as ordered.

Materials

Stone from the existing stone wall shall be utilized to reconstruct the wall at the specified location.

2.1.1 Any special stone features such as lintels, gate posts, copings, markers, etc. shall be retained for resetting.

Any added stone shall conform to the type used in the original wall.

Gravel for surface preparation shall meet the requirements of Section 209.

Construction Requirements

The reconstructed stone wall shall match the existing wall as closely as possible.

3.1.1 The Contractor shall, by photographs and measurements acceptable to the Engineer, record the width, height and configuration of the existing wall prior to removal. These photographs and measurements along with the prevailing width, hei ght and configuration shall be used to guide the reconstruction of the wall. These records shall be made at intervals of not more than 500 ft. and at locations where characteristics of the wall change. The photographs shall become the property of the Department at the end of the project. 3.1.2 When existing wall sections designated for reconstruction are in such disrepair that the original wall configuration cannot be determined, these sections shall be rebuilt to match abutting wall segments.

The stone wall reconstruction shall be supervised by a person with experience in dry masonry construction.

Care shall be taken to keep weathered faces exposed.

The Contractor shall retain all stone from existing wall for reuse. Additional stones that may be necessary shall be blended

with the existing stones in order to reproduce the appearance of the existing wall.

The Contractor shall carefully replace chinking, blocking, bond stones and headers, as appropriate to the original style of

wall, to ensure the maximum stability of the wall.

The Contractor shall carefully duplicate special features of the original wall, such as lintels, gate posts, openings, copings,

markers, etc.

The ground surface shall be prepared by removing brush, vegetation, topsoil and unsuitable material. The area shall be rough

graded to obtain a reasonably firm and level surface. Method of Measurement

Reconstructing stone walls will be measured by the linear foot, to the nearest 1 foot, along the center line of the reconstructed

wall.

Clearing and grubbing will be measured as provided in Section 201.

Gravel required for surface preparation will be measured by the cubic yard , complete in place. Limits of gravel will be as

shown on the plans, or as ordered. Basis of Payment

The accepted quantity of reconstructed wall will be paid for at the Contract unit price per linear foot complete in place.

5.1.1 Any additional stone required to complete the reconstruction will be subsidiary. 5.1.2 Reconstruction of special features as defined in 3.6 will be subsidiary. 5.1.3 Photographs and measurement records of the existing wall will be subsidiary.

Ground surface preparation will be subsidiary.

5.2.1 When special site preparation such as clearing and grubbing or gravel base courses are ordered, this work will be paid under appropriate items of the Contract. If appropriate items are not included in the Contract, this work will be paid as pr ovided in 109.04.