AASHTO HB-17 DIVISION II SEC 14-2002 Division II Construction - Stone Masonry《石砌体》.pdf

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1、Section 14 STONE MASONRY 14.1 DESCRIPTION This work shall consist of the construction of stone ma- sonry structures and the stone masonry portions of com- posite structures in accordance with these Specifications and in reasonably close conformity with the lines and grades shown on the plans or esta

2、blished by the Engineer. 14.1.1 Rubble Masonry Rubble masonry, as here specified, shall include vari- ous classes of roughly squared and dressed stone laid in cement mortar. 14.1.2 Ashlar Masonry Ashlar masonry shall consist of first-class cut stone masonry laid in regular courses and shall include

3、all work in which, as distinguished from rubble masonry, the individual stones are dressed or tooled to exact di- mensions. 14.2 MATERIALS 14.2.1 Stone for masonry shall be tough, dense, sound and durable and free of seams, cracks, inclusions or other structural defects. Stone shall be of the type a

4、nd quality shown on the plans or otherwise specified. Prior to ship- ment of stone to the job site, the Contractor shall obtain approval of the proposed source and shall submit a repre- sentative sample of stone to the Engineer for inspection and, if necessary, testing. The sample shall be dressed a

5、nd finished as specified for use in the work and shall not be less than 6 inches in any dimension. All stone used in the work shall be of a quality comparable to that of the sam- ple submitted. 14.2.1.1 Rubble Stone Stone for mortar rubble masonry shall be free from rounded, worn, or weathered surfa

6、ces. All weathered stone shall be rejected. 597 14.2.1.2 Ashlar Stone Stone for ashlar masonry shall be reasonably fine grained and uniform in color. Preferably, stone shall be from a quarry, the product of which is known to be of sat- isfactory quality. Stone shall be of such character that it can

7、be brought to such lines and surfaces, whether curved or plane, as may be required. Any stone having defects that have been repaired with cement or other materials shall be rejected. 14.2.2 Shipment and Storage of Stone Quarry operations and delivery of stone to the point of use shall be organized t

8、o insure deliveries well ahead of masonry operations. A sufficiently large stock of the spec- ified stone shall be kept on the site at all times, to permit adequate selection of stone by the masons. The stone shall be kept free from dirt, oil, or any other injurious material which may prevent the pr

9、oper adhesion of the mortar or detract from the appearance of the ex- posed surfaces. 14.2.3 Mortar The ingredients used in making mortar shall conform to the following requirements: Portland Cement, Admixtures and Water; Section 8 Masonry Cement; ASTM C 9 1 Hydrated Lime; ASTM C 207 Quick Lime used

10、 to make lime putty; ASTM C 5 Sand Aggregate; AASHTO M 45 (ASTM C 144) The proportions of materials shall be such that the volume of sand in a damp, loose condition is between 2)/4 and 3 times the volume of the cementitious materials. The cementitious materials shall consist of either one part of po

11、rtland cement to between Y4 and YZ parts of hydrated lime or lime putty, or one part of portland cement to between one and two parts of masonry cement. Premixed materials conforming to these requirements may be used. 598 HIGHWAY BRIDGES 14.2.3 Admixtures shall be used only when specified or ap- prov

12、ed by the Engineer. 14.3 MANUFACTURE OF STONE FOR MASONRY 14.3.1 General Each stone shall be free from depressions and projec- tions that might weaken it or prevent it from being prop- erly bedded, and shall be of a shape to meet the require- ments for the class of masonry specified. When no dimensi

13、ons are shown on the plans, the stones shall be furnished in the sizes and face areas nec- essary to produce the general characteristics and appear- ance as indicated on the plans. The thickness of courses, if varied, shall diminish reg- ularly from bottom to top of wall. The size of ring stones in

14、arches shall be as shown on the plans. When headers are required, their lengths shall be not less than the width of bed of the widest adjacent stretcher plus 12 inches. 14.3.2 Surface Finishes of Stone For the purpose of this specification the surface fin- ishes of stone are defined as follows: Smoo

15、th-finished Having a surface in which the varia- tions from the pitch line do not exceed %6 inch. Fine-finished Having a surface in which the varia- tions from the pitch line do not exceed Y4 inch. Rough-Jinished Having a surface in which the varia- tions from the pitch line do not exceed YZ inch. S

16、cabbled Having a surface in which the variations from the pitch line do not exceed Y4 inch. Rock-faced Having an irregular projecting face without indications of tool marks. The projections beyond the pitch line shall not exceed 3 inches and no part of the face shall recede back of the pitch line. 1

17、4.3.3 Rubble Masonry 14.3.3.1 Size Individual stones shall have a thickness of not less than 8 inches and a width of not less than 1% times the thick- ness. No stones, except headers, shall have a length less than 1% times their width. 14.3.3.2 Shape The stones shall be roughly squared on joints, be

18、ds, and faces. Selected stone, roughly squared and pitched to line, shall be used at all angles and ends of walls. If spec- ified, all corners or angles in exterior surfaces shall be fin- ished with a chisel draft. Bed surfaces of face stones shall be normal to the faces of the stones for about 3 in

19、ches and from this point may depart from normal not more than 2 inches in 12 inches. Joint surfaces of face stones shall form an angle with the bed surfaces of not less than 4.5“. All shaping or dressing of stone shall be done before the stone is laid in the wall, and no dressing or hammer- ing whic

20、h will loosen the stone will be permitted after it is placed. 14.3.3.3 Dressing Stone shall be dressed to remove any thin or weak por- tions. Face stones shall be dressed to provide bed and joint lines with a maximum variation from true line of 1% inches unless otherwise indicated on the plans or in

21、 the special provisions. 14.3.4 Ashlar Masonry 14.3.4.1 Size The individual stones shall be large and well propor- tioned. They shall not be less than 12 inches nor more than 30 inches in thickness. 14.3.4.2 Dressing Stones shall be dressed to exact sizes and shapes before being laid and shall be cu

22、t to lie on their natural beds with top and bottom truly parallel. Hollow beds will not be permitted. The bottom bed shall be the full size of the stone and no stone shall have an over-hanging top. In rock-face construction the face side of any stone shall not present an undercut contour adjacent to

23、 its bottom arris giving a top-heavy, unstable appearance when laid. Beds of face stone shall be fine-finished for a depth of not less than 12 inches. Vertical joints of face stone shall be fine-finished and full to the square for a depth of not less than 9 inches. Exposed surfaces of the face stone

24、 shall be given the surface finish indicated on the plans, with edges pitched to true lines and exact batter. Chisel drafts 1% inches wide shall be cut at all exterior corners. Face stone forming the starling or nosing of piers shall be rough-finished unless otherwise specified. Holes for stone hook

25、s shall not be permitted to show in exposed surfaces. 14.3.4.3 DIVISION II-CONSTRUCTION 599 14.3.4.3 Stretchers Stretchers shall have a width of bed of not less than 1% times their thickness. They shall have a length of bed not less than twice nor more than 3% times their thickness, and not less tha

26、n 3 feet. 14.3.5 Arch Ring Stones Arch ring stone joint surfaces shall be radial and at right angles to the front faces of the stones. They shall be dressed for a distance of at least 3 inches from the front faces and the soffits, from which points they may depart from a plane normal to the face not

27、 to exceed 74 inches to 12 inches. The back surface in contact with the concrete of the arch barrel shall be parallel to the front face and shall be dressed for a distance of 6 inches from the intra- dos. The top shall be cut perpendicular to the front face and shall be dressed for a distance of at

28、least 3 inches from the front. When concrete is to be placed after the masonry has been constructed, adjacent ring stones shall vary at least 6 inches in depth. Stratification in arch ring stones shall be parallel to the radial joints and in other stones shall be parallel to the beds. When specified

29、 in the special provisions, a full-sized template of the arch ring shall be laid out near the quarry site, showing face dimensions of each ring stone and thickness of joints. The template shall be approved by the Engineer before the shaping of any ring stone is started, and no ring stone shall be pl

30、aced in the structure until all ring stones have been shaped, dressed, and approved by the Engineer. 14.4 CONSTRUCTION 14.4.1 Weather Conditions Stone masonry shall not be constructed in freezing weather or when the stone contains frost, except by writ- ten permission of the Engineer and subject to

31、such condi- tions as he or she may require. 14.4.2 Mixing Mortar The mortar shall be hand or machine mixed, as may be required by the Engineer. In the preparation of hand- mixed mortar, the sand and cement shall be thoroughly mixed together in a clean, tight mortar box until the mix- ture is of unif

32、orm color, after which clean water shall be added in such quantity as to form a stiff plastic mass. Ma- chine-mixed mortar shall be prepared in an approved mixer and shall be mixed not less than 3 minutes nor more than 10 minutes. Mortar shall be used within 1% hours after mixing and before final se

33、t begins. Retempering of mortar shall be done as necesiary to maintain proper con- sistency during placement. 14.4.3 Selection and Placing of Stone 14.4.3.1 General When masonry is placed on a prepared foundation bed, the bed shall be firm and normal to, or in steps normal to, the face of the wall,

34、and approved by the Engineer before any stone is placed, When it is placed on foundation ma- sonry, the bearing surface of the foundation masonry shall be cleaned thoroughly and in a saturated-surface dry con- dition when the mortar bed is spread. All masonry shall be constructed by experienced work

35、- men. Face stones shall be set in random bond to produce the effect shown on the plans. Care shall be taken to prevent the bunching of small stones or stones of the same size. When weathered or col- ored stones, or stones of varying texture, are being used, care shall be exercised to distribute the

36、 various kinds of stones uniformly throughout the exposed faces of the work. Large stones shall be used for the bottom courses and large, selected stones shall be used in the corners. In general, the stones shall decrease in size from the bottom to the top of work. Each stone shall be cleaned and th

37、oroughly saturated with water before being set and the bed which is to receive it shall be clean and well moistened. All stones shall be well bedded in freshly made mortar. The mortar joints shall be full and the stones carefully settled in place be- fore the mortar has set. No spalls will be permit

38、ted in the beds. No pinning up of stones with spalls will be permit- ted in beds. Stone shall not be dropped upon, or slid over the wall, nor will hammering, rolling, or turning of stones on the wall be allowed. They shall be carefully set without jarring the stone already laid and they shall be han

39、dled with a lewis or other appliance that will not cause disfigurement. In case any stone is moved or the joint broken, the stone shall be taken up, the mortar thoroughly cleaned from bed and joints, and the stone reset in fresh mortar. 14.4.3.2 Rubble Masonry Rubble masonry shall be laid to line an

40、d in courses roughly leveled up. The bottom or foundation courses shall be composed of large, selected stones and all courses shall be laid with bearing beds parallel to the natural bed 600 HIGHWAY BRIDGES 14.4.3.2 of the material. The vertical joints in each course of rub- ble masonry shall break w

41、ith those in adjoining courses at least 6 inches. In no case shall a vertical joint be so located as to occur directly above or below a header. 14.4.3.3 Ashlar Masonry The stones in any one course of ashlar masonry shall be placed so as to form bonds of not less than 12 inches with the stones of adj

42、oining courses. Headers shall be placed over stretchers and, in general, the headers of each course shall equally divide the spaces between the headers of adjoining courses, but no header shall be placed over a joint and no joint shall be made over a header. 14.4.4 Beds and Joints Beds and joints in

43、 rubble masonry shall have an aver- age thickness of not more than 1 inch. Beds and joints in ashlar masonry shall be not less than YE inch nor more than YZ inch in thickness and the thickness of the joint or bed shall be uniform throughout. The thickness of beds in ashlar masonry may vary as shown

44、from the bottom to the top of the work. However, in each course the beds shall be of uniform thickness throughout. Beds shall not extend in an unbroken line through more than five stones. Joints in ashlar masonry shall be vertical. In all other masonry, joints may be at angles with the vertical from

45、 O“ to 45“. Each face stone shall bond with all contiguous face stones at least 6 inches longitudinally and 2 inches verti- cally. Ring stone joints on the faces and soffits shall be not less than Y4 inch nor more than 1% inches in thickness. Cross beds for vertical walls shall be level and for bat-

46、 tered walls may vary from level to normal to the batter line of the face of the wall. All joints shall be completely filled with mortar. 14.4.5 Headers Headers shall hold in the heart of the wall the same size shown in the face and shall extend not less than 12 inches into the core or backing. They

47、 shall occupy not less than one-fifth of the face area of the wail and shall be evenly distributed. Headers in rubble masonry walls 2 feet or less in thick- ness shall extend entirely through the wall. Headers in ashlar masonry shall be placed in each course and shall have a width of not less than 1

48、% times their thickness. In walls having a thickness of 4 feet or less, the headers shall extend entirely through the wall. In walls of greater thickness, the length of headers shall be not less than 2% times their thickness when the course is 18 inches or less in height, and not less than 4 feet in

49、 courses of greater height. Headers shall be spaced not fur- ther apart than 8 feet center to center. There shall be at least one header to every two stretchers. 14.4.6 Cores and Backing 14.4.6.1 General Cores and backing shall consist either of roughly bed- ded and jointed headers and stretchers, as specified above, or of Class B or C concrete, as may be specified. The headers and stretchers in walls having a thickness of 3 feet or less shall have a width or length equal to the full thickness of the wall. No backing will be allowed. 14.4.6.2 Stone #en stone is used for cores or backing, at l