SPECIFICATIONS FOR STONE MASONRY. 271 



f concrete. 



46. Backing. Backing shall consist of j large stone, shaped to fit the arch bonded to the spandrel 



(. and laid in full bed of mortar. 



47. Where waterproofing is required, a thin coat of mortar or grout shall be applied evenly 

 for a finishing out, upon which shall be placed a covering of approved waterproofing mutt-rial. 



4,s. Out i TS >hull not be struck until directed by the engineer. 



41). Bench Walls, Piers, Spandrels, etc. Bench walls, piers, spandrels, parapets, wing walls 

 ami copings shall be built under the specifications for Bridge and Retaining Wall Masonry, 

 Ashlar Stone. 



ARCH MASONRY RUBBLE STONE. 



50. Arch Masonry, Rubble Stone. Voussoirs shall be full size throughout, and shall have 

 bond not less tli.iu thickness of voussoirs. 



51. Dressing. Beds shall be roughly dressed to bring them to radial planes. 



52. Mortar joints shall not exceed one (i) in. 



53. tface or Surface. Exposed surfaces of the ring stone shall be rock-faced, and edges 

 pitched to true lines. 



54. Voussoirs shall be placed in the order indicated on the drawings. 



[ concrete. 



55. Backing. Backing shall consist of j large stone, shaped to fit the arch, bonded to the span- 



[ drel, and laid in full bed of mortar. 



56. Where waterproofing is required, a thin coat of mortar or grout shall be applied evenly 

 for a finishing coat, upon which shall be placed a covering of approved waterproofing material. 



57. Centers shall not be struck until directed by the engineer. 



58. Bench Walls, Piers, Spandrels, etc. Bench walls, piers, spandrels, parapets, wing walls 

 and copings shall be built under the specifications for Bridge and Retaining Wall Masonry, 

 Rubble Stone. 



CULVERT MASONRY. 



59. Culvert Masonry. Culvert Masonry shall be laid in cement mortar. Character of 

 stone and quality of work shall be the same as specified for Bridge and Retaining Wall Masonry, 

 Rubble Stone. 



60. Side Walls. One-half the top stone of the side walls shall extend entirely across the 

 wall. 



61. Cover Stones. Covering stone shall be sound and strong, at least twelve (12) in. thick, 

 or as indicated on the drawings. They shall be roughly dressed to make close joints with each 

 other, and lap their entire width at least twelve (12) in. over the side walls. They shall be doubled 

 under high embankments, as indicated on the drawings. 



62. End Walls, Coping. End walls shall be covered with suitable coping, as indicated on 

 the drawings. 



DRY MASONRY. 



63. Dry Masonry. Dry Masonry shall include dry retaining walls and slope walls. 



64. Retaining Walls. Retaining Walls and Dry Masonry shall include all walls in which 

 rubble stone laid without mortar is used for retaining embankments or for similar purposes. _ 



65. Dressing. Flat stone at least twice as wide as thick shall be used. Beds and joints 

 shall be roughly dressed square to each other and to face of stone. 



66. Joints shall not exceed three-quarters (J) in. 



67. Disposition of Stone. Stone of different sizes shall be evenly distributed over entire 

 face of wall, generally keeping the larger stone in lower part of wall. 



68 The work shall be well bonded and present a reasonably true and smooth surface, free 

 from holes or projections. 



69. Slope Walls. Slope Walls shall be built of such thickness and slope as directed by the 

 engineer. Stone shall not be used in this construction which does not reach entirely through the 

 wall. Stone shall be placed at right angles to the slopes. The wall shall be built simultaneously 

 with the embankment which it is to protect. 



