The way society forgets the past, often within one generation, is really strange. Between past practices, best practices and new practices, it is the past practices that possibly face the first blow from societal forgetfulness.
There was a time when concrete columns did not exist, and now we are going through a time where non-concrete columns are seemingly non-existent, as if they have vanished from our imaginations.
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To state it simply, the wall is nothing but an elongated column and the column is an extremely short wall. Technically though, there are differences in the way they behave and transfer loads, which the structural engineers will consider before deigning them.
Most short span spaces such as verandahs, pavilions, sheds, and small rooms around 10 ft. span do not require RCC columns, but can be managed with columns erected using the same masonry material with which the building walls are built. In the case of higher loads, where we wish to reduce concrete, the brick column can be reinforced with structural steel.
While both the words ‘column' and ‘pillar' are found in common usage, the word ‘ column' is more applicable to RCC while non-RCC ones like stone, wooden or brick ones are referred to as pillars.
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Drawbacks
There are many examples and past attempts towards reinforced pillars using cement water pipes, hollow cement blocks and such others. They all require external plaster finish, may not have the minimum concrete volume to embed the steel or finally end up using high embodied energy materials like cement all over.
Alternatively, hollow clay blocks and jaali bricks are preferable, also due to the availability of internal perforations to run the steel through.
Steel rods
In the chosen hollow block, the number of voids and the distances are fixed; as such the numbers of steel rods have to be designed to take the roof, people and materials' load from upper floors.
Every joint is to be used to have the steel tie called stirrups, placed within the mortar bed.
The rods are first erected from the ground up with some temporary support, each block is inserted from top down, stirrups either slipped down or freshly tied there, and voids and joint finished with mortar. Next, another block is inserted and so goes the process.
Ensuring the rods are held vertical, each block is filled with concrete made with 12 mm jelly. Blocks should be well soaked with water to reduce cement water absorption.
Placing details
The last course often does not match with the desired slab or beam bottom, where concrete packing or blocks cut thin can be considered. Each block has to be placed perfectly horizontal, within the margins of dimensional variations, otherwise joints will visibly appear angular.
Wiping the blocks regularly and externally covering the pillar with construction plastics during roof casting ensures least damage to the surface, later to be left exposed.
Reinforced hollow brick pillar is a simple method to get the best of both worlds – strength and aesthetics.
(The writer is an architect working for eco-friendly designs and can be contacted at varanashi@gmail.com)