Natural bed of stones-Civillearners
Importance of Natural bed of stones
In stone masonry structures, generally, the rules observed are that the line or direction of the natural bed stones should be nearly so to the direction of pressure or perpendicular or Such an arrangement gives maximum strength to stonework. Natural beds of stones can be examined by pouring water and examining the directions of layers. A magnifying glass may also be used for this purpose. An experienced worker can easily locate and check the direction of the natural bed of stones from the resistance offered to the chisel. Stones break easily along these natural beds. With respect to natural bed, stones are placed in different situations as follows:
In this type of stone arches, the stones are placed with their natural beds radial as shown in fig. With such an arrangement, the thrust or the force of the arch weight above acts normal or perpendicular to the direction of the natural bed stone arch.
2) Cornices, string courses, etc.:
In the case of cornices, stones are partially unsupported, string courses, etc. Hence they should be placed with the direction of natural beds as vertical. This principle will not hold good for cornerstones. It would be desirable, in such cases, to adopt stones without natural beds.
Stones should be placed in walls with the direction of their natural beds horizontal as shown in fig.