Hello, friends what up? Today in this post we will discuss bout the Stone Masonry wall of the building. If you are a civil engineer or overseer this basic information is very important to you. so I have included this topic today. please stay tuned till the end of the page. I hope this post is very helpful for you. Let’s get started:
What is a Stone Masonry wall?
Masonry defines as the construction of a building unit bonded together with mortar when stones use on the building units called stone masonry.
Hello friends, in this article I will explain the Stone Masonry wall. If you need knowledge about the stone or rock you can check out the link click here. But friends in this article about the following topic:
- Technical terms of stone masonry
- Require materials for stone masonry
- Safe permissible load on stone masonry
- Classification of stone masonry
- The observation principle of stone masonry
- Joint in stone masonry.
Some technical terms used in Stone Masonry wall
Natural bed: this term is used in stone masonry only. It is well known that rocks from which stone for masonry obtain distinct planes of division along which stone can easily split. This plane represents the natural bed of the stone. In stone masonry, a natural bed of stone should keep perpendicular to the direction of the pressure.
Course: A horizontal layer of stone is known as a Course. In stone masonry thickness of course cannot be standardized as stones are not available in any one size.
Bed: the lower surface of stones on which the rest in a course is known as a bed.
Hearing: the space of the wall between facing and backing is known as hearing.
Joint: The place where two or more stores meet is called a joint.
The joint between the successive course of stones is known as the bed joint.
The joint between various units in a course is known as a vertical joint.
Through stone: in stone masonry, some stones at regular intervals are placed right across the wall. Such stones are known as through stones or bond stones and sometimes only through. These stones keep both the face of the wall securely held together.
If the thickness of the wall is considerable, two through stones with suitable overlap provide.
The area covered by the through stones should be about 1/4 the to 1/2 of the area of the wall surface in the plan. Through stone should be nonporous to prevent any moisture from getting into the wall.
Plinth course: the topmost course of masonry to attain plinth is known as the plinth course.
String course: it is a continuous horizontal course of masonry generally provided at every floor or sill level. This course remains projecting from the face of a wall and is suitable weathered and throated to through off rainwater, clear off the wall face.
Corbel: it is a projection provided on the inside face of the wall by the projection of one or more course of stones. The projection is used to serve as a support for wall plates for roof trusses, beams, etc. The collet stones should rest at least 2/3rd of their width into the wall to prevent its overturning before trusses make it to rest on them.
Cornice: this molder course of masonry heaving large projection may provide at the junction of a wall and ceiling or near the building. Cornice stone should have sufficient bearing on the wall and also sufficient weight on it to prevent its overturning.
Weathering: is the term used to indicate the level to the surface of the stone, sills, cornices, and coping stones bevel at the top surface in a sloping way to allow easy flow and rainwater.
Throating: Ii is a term that applies to the groove formed on the underside of a cornice, sill, and coping stones. This groove helps to throw away rainwater, and clear the wall surface.
Coping: it is a course of stone, concrete, or brick, provided at the top of the wall to protect the wall from seepage of rainwater through the joints of the topmost course of the wall.
Block in the course: this is a course of stone masonry, provided above the cornice to hold down the cornice against the tendency of overturning. It also adds to the appearance of the structure.
Frieze: it is a course of the stone provided immediately below the cornice. It is gradually kept flush with the wall and may have architectural moldings from the appearance point of view.
Spalls: Stone chips broke off from large size stones during dressing and shaping known as spalls. Spalls use to fill up the empty spaces in the stone masonry with mortar. Spall is known as snecks.
Template: it is a block of stone used under the bearing ends of beams. It distributes the concentrated load transferred by beam reaction over a large area of a load-bearing wall.
Moldings: their ornamental features give constructional members to their aesthetic appearance.
Material for Stone Masonry wall
The stone used for masonry should be hard, durable, tough, sound, and free from weathering, decay, or defect like cracks, sand holes, injuries, patches of loose or soft materials, etc.
The stones should be obtained only from the approved quarry.
The stone unit should obtain by quarrying large massive rocks and not by breaking small size boulders having rounded faces. Rocks from which building stones obtain divided into three groups.
Mortar is the choice and mortar grade for binding masonry units to each other for considerations such as type of masonry, load intensity, situations of use, degree of exposure to weather conditions for bond and durability requirements, and other special considerations like fire resistance, insulation, rate of setting and hardening, etc.
In stone masonry cement mortar, lime mortar, and mud mortar are used.
Safe Permissible Loads on Stone Masonry
The strength of stone masonry depends upon the following factors:
- Stone ( i.e sandstone, limestone)
- Masonry (i.e coursed rubble, ashlar, etc)
- Mortar (i.e lime mortar, cement mortar)
The basic stresses are based on the compressive strength of stone units and various types of mortars
Safe Permissible load on stone masonry
Ashlar masonry in 1:3 cement mortar
Granite = 1600 KN/m2
Sand stone = 1100 KN/m2
Lime stone = 700 KN/m2
Ashlar masonry in lime mortar
Granite = 1100 KN/m2
Sand stone = 800 KN/m2
Lime stone = 500 KN/m2
Coursed rubble masonry in 1:3 cement mortar
Granite = 1200 KN/m2
Sand stone = 1000 KN/m2
Lime stone = 600 KN/m2
Coursed rubble masonry in lime mortar
Granite = 900 KN/m2
Sand stone = 700 KN/m2
Lime stone = 400 KN/m2
Random rubble masonry in 1:3 cement
mortar = 600 to 1200 KN/m2
Random rubble masonry in lime mortar = 400 to 600 KN/m2
Classification of stone masonry
Stonemasonry can be classified into main two types. Which is listed below. The classification of stone masonry is in the construction used of the arrangement of stones, shaping of stones, and finishing of stones masonry. Types of stone masonry:
- Rubble masonry
- Ashlar masonry
In the rubble masonry, the blocks of stone that are used are either undressed or comparatively rough dressed.
The stone masonry has a wide joint, till the irregular size and shape stone should be used.
Rubble masonry is also categorized into the following types:
Random Rubble course
This is the roughest and cheapest form of stonewalling. In random rubble masonry, the stones should be used in widely different sizes and shapes.
Since the stones are not of uniform size and shape, greater care and ingenuity have to be exceeded in arranging them in such a way that they adequately distribute the pressure over the maximum area, and at some time long continuous vertical joints are avoided.
Random Rubble Built to course
This method of construction is the same as non-course except the works are roughly leveled up to form a course varying from 30 to 45 thick. For the construction of this type of masonry, quoins are built first and the line is stretched between the tops of quoins. The intervening walling is then brought up to this level by using different sizes of stones.
This type of masonry is better than non-course random rubble masonry.
Square Rubble Uncoursed
Square rubble masonry user stones have straight beds and sides. The shape of stones is usually squared in shape and brought to hammer dressed or straight cut finish of the stone.
In the course square rubble also sometimes known as square snacked rubble, the stones with straight edges and sides are available in different sizes. They are arranged on the face in several irregular patterns.
A good appearance can be achieved by using a (riser) large stone, (leveler) thinner stone, and ( sneck) small stones in a pattern having their depth of 3:2:1 respectively.
R= Riser : 3
L= Leveller : 2
S= Sneck : 1
Square Rubble Built to course
This type of masonry also uses the same stones as used for non-course square rubble. But the work is leveled up to course may consist of quoins, jamb stones built in between them up to the height of the larger stones to complete the course.
Square Rubble Regular Coursed
In this type of masonry, the wall consists of various courses of varying height, but the height of stones in one particular course is the same.
Polygonal walling (polygonal rubble masonry)
In this type of stone, the hammer finished the face to an irregular polygonal shape? These stones are bedded in the partition to show face joints running irregularly in all directions.
Two types of polygonal walling may be there. The first type of stone was only roughly shaped, resulting in only rough fitting, such work is called a rough pick. In the second type, the faces of stones more carefully form so that they fit more closely. such work is called close-pick work.
Flint walling (Flint rubble masonry)
The stones used in this masonry are Flints or cobbles, which vary in width and thickness from 7.5 to 15 cm and in length from 15 to 30 cm.
There are irregularly shaped nodules of silica. The stones are extremely hard. But they are brittle and therefore may break easily. The face arrangement of the cobbles may be either course or non-course or built to course strength of Flint wall may increase by introducing backing courses of either thin long stones.
Dry rubble masonry
Dry rubble masonry is rubble masonry makes to the course in which mortar does not use in the joints. This type of construction is the cheapest and requires more skilled construction. This may use for non-load-bearing walls such as compound walls etc.
Accurately dressed stone blocks with found stone beds and end joints called ashlar masonry.
The block of stone should be square and rectangular shape in this masonry. The height of stones varies from 25 to 30 cm. The height of blocks in each course keep equal but it is not necessary to keep all the courses of the same height. Ashlar masonry may categorize into the following.
- Fine tooled
- Rough tooled
- Rock, rustic, or quarry faced
- Block in the course
Ashlar Fine tooled
This is the finest type of stone masonry work. Each stone is cut to the regular and required size and shape to have all sides rectangular so that the stone gives a perfectly horizontal and vertical joint with adjoining stone.
The thickness of courses is generally not less than 15 cm.
The width of the stone does not keep less than 15 cm.
The thickness of the mortar joint keeps uniform throughout and it should not be more than 5 mm. The exposed joints finely point.
Ashlar Rough Tooled
In this type of masonry, the beds and sides of each stone block are finely chiseled dressed first in the same manner as for ashlar fine, but the exposed face is dressed by rough tooling.
The thickness of the joint in this masonry doesn’t exceed 6 mm.
Ashlar Rock Faced ( rustic or quarry faced)
In this type of masonry, the face of the stone in the exposed face is not dressed but the stone gives in to the rock facing.
However, a strip of about 25 mm wide, made using a chisel, provides around the perimeter of the exposed face of every stone.
Projection on the face exceeding 8 cm remove with the help of a hammer. Such projection (exceeding 8 mm) is also called bushing.
The height of each block may vary from 15 cm to 30 cm.
In this masonry 2.5 cm, chisel drafting around the face, not leff plane but it chamfer or bevel at an angle of 45° with the help of a chisel.
Another chisel drafting about 10 mm to 12 mm wide again develops around the perimeter inside the chamfered drafting.
The remaining enclosed space is left as such. However, a projection of more than 8 cm removes with the help of hammers.
Ashlar block in the course
This masonry is intermediate between rubble masonry or ashlar masonry.
The faces of each stone hammer dress and the height of blocks keep the same in any course, though it is not necessary to keep uniform height for all the courses.
This type of masonry adopts in heavy works such as retaining walls bridges etc.
This facing masonry provides along with brick or concrete block masonry to give a better appearance.
The sides and bed of each block are properly dressed to make the truck shape.
The stone exposes the face rough tool and chamfered.
The backing of the wall may make of brick masonry.
General principles that should observe in the Stone Masonry wall
- The stone used should be strong, tough, hard, and should confine to the specification of work. The stones should be free from defects like cracks, flaws, cavities, etc.
- The stones should be well-watered before use so that they do not observe water from the mortar.
- All the stones should lay on their natural bed.
- Stones to use should dress properly according to the type of masonry.
- A proper bond should maintain. Formation of the vertical joint should avoid.
- No tensile stress should allow development in the masonry.
- Masonry work should raise uniformly so that the nonuniform distribution of load on the foundation avoid.
- Broken stone, small pieces, and chips should not use for facing and backing. However, this may use in hearting for proper packing with mortar.
- The facing and backing of the wall should be well bound by stones. The through stones should lay staggered in the successive courses. The center-to-center distance between them should not exceed 1.5 m.
- The mortar to use for the work should be of proper quality and proportion. Masonry work may do in mud mortar, lime mortar, or cement mortar.
- Quoins used to form the joints for windows, doors and other openings should of the full height of the course. The breath and length of quoin should at least be 1.5 times and twice its depth respectively.
- The vertical surface of the wall should construct perfectly is plumb. They should frequently check.
- The joint in stone masonry should be properly filled with mortar and stone chippings.
- Where it requires raising new construction over the old or dry one it should be well cleaned and wetted before starting construction.
- Double scaffolding should adopt to carry out the stone masonry construction at a high level.
- The exposed joint of the masonry should properly point by cement mortar or lime mortar, by racking them first up to a depth of about 2 cm.
Joints in Stone Masonry wall
The junction of adjacent units of stones is known as a joint. Parallel to the bed of brick or stones is the bed joint. Bet joints are thus horizontal mortar joints upon which stones are laid.
Joints perpendicular to the face of the wall is known as cross joints or vertical joints.
Following are the common types of joints provided in stone masonry wall:-
Butt joint or square joint
Most commonly used.
The dressed edge of two adjacent stones is placed side by side.
Rebated or lapped joint
This type of joint is provided in arches copings etc.
The length of the rebate or lap should not be less than 70 mm.
Tongue and groove joint or joggle joint
This type of joint provides to prevent sliding along the side joints
Tabled or bed joint
This joint is used to prevent lateral movement of stones such as in sea walls where the lateral pressure is heavy.
The height of the projection keep 30-40 mm and the width keeps equal to 1/3rd of the width of the stone.
The joint uses a mental cramp.
Cramps are usually non-corrosive metals.
Length =20-30 cm
Width =2-4 cm
Thickness =5-10 mm
Cramp prevents the tendency of the joints to open out.
The joint form by cutting rectangular holes in each stone and inserting dowels.
The stonemasonry wall is the wall of the building. The wall of the building should be made with the help of Stone which is a stone masonry wall. I hope this post is very helpful for you. If you like and are helpful please share this post with your friend and comment in the comment section.
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