What is Curve Section Brick wall?
The straight masonry brick wall can be easily constructed with the help of the threads and plumb bob (for verticality check) or simply with help of spirit levels.
But the curve section of the brick wall cannot be simply made as a straight section wall by the simple alignment of bricks. Sprit levels, gauges,s, and templates are used for curve brick wall construction.
And the mortar joints for straight masonry brick walls ranges can be of 10mm to 20 mm of uniform thickness between the two joints of bricks. But for curved bricks joints can range from 6mm to 15 mm between the same two bricks due to the radial arrangement needed to gain curvature.
The radius of curvature or say degree of curvature affects the use of brick size needed to be useful and also types of bonding structure.
For larger curve section (having greater radius) the full bricks can be aligned simply along with some radial arrangement of joint gaps and bricks i.e. more joint gap at outer face and tapering toward the end.
But for a higher degree of curvature (having less radius) walls bricks must be cut into smaller units with the radially reduced structure giving trapezoidal structure. However, it can also be done by adopting the brick bonding pattern, like using header bonds.
Generally, stretcher bonds are preferred to be used for larger radii of 3.5m to 4m and header bond for 2.5m to 3m.
According to IS – SP 20 (S & T):1991, the ordinary brickwork can be adopted for the curve section having a radius of curvature greater than 6m with simple alteration on the joint gap.
But for a curve having less than 6m of the radius of curvature, the bricks are needed to be specially designed or cut into required shapes, and then the arrangement of bricks is done to obtain a smooth curve. But for the rough works like pit holes and septic tanks, the bricks are simply struck by the sharp object instead of cutting into definite shapes.
Moreover, the joints greater than 15mm also can be constructed but for this, some modification in mortar is required by adding the coarser aggregates.
How to build a curved brick wall? – Procedure
The curve is first set out with help of the compass or ruler with the marking edges, by calculating the required radius needed for the required curvature of the wall.
The external curve of required curvature is first set out and then internal is set out by finding internal radius by deducing width of wall on the external radius.
i.e Internal radius ( r ) = External radius ( R ) – Thickness of wall (W)
or, vice versa process can be attained.
The bricks are arranged along with joint space in the boundary of the drawn curve to check whether the bricks are needed to cut for small pieces of required shapes or not for smooth curvature.
This is based on the principle that; the circle is a polygon with infinite numbers of sides or line segments. The polygon with more than 16 sides almost looks like a circle from far.
Then after that required shapes of bricks are cut if necessary. While arranging bricks radially along with curvature the inner side between the brick might have less space for mortar joint formation.
So, the bricks are cut radially as much as possible or simply the corner of bricks at inner face are knocked out to form space for mortar.
The space for mortar can be also geometrically designed, but the process is very precise and only use for precise work and theoretical calculation and are not suitable for the practical approach of manual construction.
After removing initially laid brick without mortar and required processing of brick, the mortar is initially laid to the drawn curve.
Then the bricks are laid over the mortar layer arranging in the required curvature as before along with the mortar joints. The level of bricks is checked along with spirit level and curvature using the templates.
The upraised bricks are struck with the back end of the trowel so that the mortar displaces and the required level is achieved.
After confirming the uniform level of the first laid bricklayer the mortar is overlaid over the layer.
The mortar should be serrated or formed a rough structure with the help of a trowel before laying the bricks.
Then the bricks are laid over it. The brick can be of similar size and shape as in of first layer (for uniform thickness and vertical curved walls), so the need for estimating the size and shapes is done before this time.
During the laying, the brick in the next layers great care should be taken, so that no joints of the above layer coincide with joints on its adjacent layers.
This will help to prevent failure through the joint of the masonry wall during the application of loads over it. Also, each layer is check for level. Verticality and curvature with help of spirit level and templates.
The consecutive layers are similarly placed one above another along with checking of levels and curvature of brick alignment.
The wall must be constructed up to 100cm – 150cm at a time and remaining work must be carried out only after drying of mortar.
I hope this article on “how to build a curved brick wall step by step?” remains helpful for you.
Happy Learning – Civil Concept
Civil Engineer – Rajan Shrestha