11 Pillars

11.1 General

11.1.1 Pillars are to be fitted in the same vertical line wherever possible. If not possible, effective means are to be provided for transmitting their loads to the supports below. Effective arrangements are to be made to distribute the load at the heads and heels of all pillars. Where pillars support eccentric loads, they are to be strengthened for the additional bending moment imposed upon them.

11.1.2 Pillars are to be provided in line with the double bottom girder or as close thereto as practicable, and the structure above and below the pillars is to be of sufficient strength to provide effective distribution of the load. Where pillars connected to the inner bottom are not located in way of the intersection of floors and girders, partial floors or girders or equivalent structures are to be fitted as necessary to support the pillars.

11.1.3 Pillars provided in tanks are to be of solid or open section type.

Where the hydrostatic pressure may result in tensile stresses in the pillar, the tensile stress in the pillar and its end connections is not to exceed 45% of the specified minimum yield stress of the material.

11.2 Connections

11.2.1 Heads and heels of pillars are to be secured by thick doubling plates and brackets as necessary. Alternative arrangements for doubling plates may be accepted, provided that they are considered equivalent as deemed appropriate by the Society. Where the pillars are likely to be subjected to tensile loads, the head and heel of pillars are to be efficiently secured to withstand the tensile loads and the doubling plates replaced by insert plate.

The net thickness of doubling plates, when fitted, is to be not less than 1.5 times the net thickness of the pillar. Pillars are to be attached at their heads and heels by continuous welding.