The document discusses concrete columns, which are vital structural members that transfer loads from beams and slabs to the ground. It traces the evolution of columns from ancient civilizations, highlighting their significance in Egyptian, Persian, Greek, and Roman architecture, and notes the decline of large structural columns during the Middle Ages. Additionally, it outlines modern concrete column construction requirements, including the use of steel reinforcement and necessary materials and techniques.

1. Concrete Columns
By builtify

2. • Columns are basically rigid vertical structural members designed primarily to
support axial compressive loads coming from beams and slabs and then
transfer it to ground through footing.
• In our human body bones give strength as well as transfer over body weight
to bottom i.e. to over legs, in the same way the different loads that are
generated in a structure are transferred by column to footings and footing to
soil.
• So, column plays an important role in whole load transfer mechanism and
without it structure doesn’t exists.
• Columns has a great history which shows how it evolved in the past to be
very good in providing support to the buildings.

3. History of columns
• Antiquity:-
The antiquity in columns are came mostly from middle east & mediterranian in
iron age civilization.
• Many civilization has many effect in development of columns both in asthetic
& engineering way.
• This column has evolved mostly in egyptian civilization,Persian
civilization,Greek & Roman civilization,middle ages.

4. Egyptian architecture & columns
• In ancient egyptian architecture as early as 2600 B.C architect Imhotep
made use of stone columns whose surface was carved to reflect the
organic form of bundled reeds, like papyrus, lotus and palm; in later
Egyptian architecture faceted cylinders were also common.
• Their form is thought to derive from archaic reed-built shrines. Carved
from stone, the columns were highly decorated with carved and painted
hieroglyphs, texts, ritual imagery and natural motifs.

5. • One of the most important type are the papyriform(lotus) columns.
• They are composed of lotus (papyrus) stems which are drawn together into a
bundle decorated with bands: the capital, instead of opening out into the
shape of a bellflower, swells out and then narrows again like a flower in bud.
• The base, which tapers to take the shape of a half-sphere like the stem of the
lotus, has a continuously recurring decoration of stipules.

7. Persian architecture & columns
• Some of the most elaborate columns in the ancient world were those of the
Persians, especially the massive stone columns erected in Persepolis. They
included double-bull structures in their capitals.
• Many of the ancient Persian columns are standing, some being more than
30 metres tall.

8. • Tall columns with bull's head capitals were used for porticoes and to support
the roofs of the hypostylehall, partly inspired by the ancient Egyptian
precedent.
• Since the columns carried timber beams rather than stine, they could be taller,
slimmer and more widerly spaced than Egyptian ones.

9. Greek & Roman architecure & columns
• This civilization used whole tree-trunks, usually turned upside down in order
to prevent re-growth, stood on a base set in the stylobate (floor base) and
topped by a simple round capital. These were then painted as in the most
famous Minoan palace of Knossos.
• The Egyptians, Persians and other civilizations mostly used columns for the
practical purpose of holding up the roof inside a building, preferring outside
walls to be decorated with reliefs or painting, but the Ancient Greeks,
followed by the Romans, loved to use them on the outside as well, and the
extensive use of columns on the interior and exterior of buildings is one of the
most characteristic features of classical architecture, in buildings like the
Parthenon.

11. Middle Ages
• Columns, or at least large structural exterior ones, became much less
significant in the architecture of the Middle Ages.
• At the end of this middle age period i.e Romanesque period, builders
continued to reuse and imitate ancient Roman columns wherever
possible. Where new, the emphasis was on elegance and beauty, as
illustrated by twisted columns. Often they were decorated with mosaics.

12. • Later on the columns are developed day by day and in today's modern world the
style and the way columns are made totally changed.
• Now a days concrete columns are more liked by people & also accepted by
architectures due to easy construction process as compared to the stone
columns which is previously used.

13. What material required for modern day concrete
column construction

14. Concrete column is load bearing structure which provide strength to
buildings,So for that what materials are required & what are the
important aspects that is discussed in the bellow slides.

15. Steel Rods
• Plain concrete without steel or other reinforcement is strong in compression,
but weak in tension .
• Steel is one of the best forms of reinforcement to take care of stress & to
strengthen concrete to bear loads.
• It forms the basis concrete structure and is generally laid out in a circular
cross section.
• But the steel rods used in making of framework must be of good quality, It
must be free from loose rust, oil paints, mud etc.,& cut, bent & fixed properly.

16. • The bar should be placed & maintained in position by using proper cover blocks,
spacers,supporting bars ,laps etc.
• For general house construction,6-20 mm diameter bars are used .Mild steel
bars and deformed bars are used, with the latter used most commonly now a
days, because of higher strength and the reduced requirement of steel.
• Thermo mechanically treated (TMT) & corrosion-resistant steel bars with added
features have been introduced recently. Remember to purchase ISI certified
steel bars, from reputed manufacturers, regardless of the size you choose.

17. Lap length
• Lap length is provided at the junction where an old bar that terminates and
join new extension bar. Lap length of about 50 times the diameter of the bar
is considered safe. All laps should be staggered and not provided at one
place. A maximum of 50% bars should be lapped per section.
• If the required lap length is not available at the junction owing to space and
other constraints, couplers or the correct method of welding should be used
to join bars.

19. Anchorage length
• This is the additional length of steel of one structural member necessary
for insertion with another member at the junction .
• For example, the beam with the pillar, or the pillar with the foundation.
The required length is similar to the lap length mentioned above or as per
design instructions.

20. Cover Blocks
• Cover blocks are placed to prevent the steel rods from rusting due to
exposure to air, and to fix the bars in place. Sometimes during the correcting
activity,the covers tend to get displaced.
• To prevent this tie the cover block using thin steel wires called binding wires
to the steel bars.
• Cover should be made of cement and sand mortar. The blocks could be
cubical or cylindrical in shape.
• Normally, cubical cover blocks are used. As a thumb rule ,a minimum cover
of 2” in footings,1.5” in columns and ½” to ¾” for slabs and beams is
recommended.

22. Shuttering
• The framework or shuttering should be rigid and closely fitted, with
sufficient strength to support wet concrete.
• It should be leak proof to prevent the cement –sand-water mix from
leaking .
• The face of framework should be treated with form release agents
available in the market or a mixture of diesel and grease.

24. Now a days steel frameworks are used which is very convinient to work.

25. Deshuttering
• Removal of shutters (deshuttering)results in the concrete being subjected
to loads and exposure to the atmosphere.
• If the ambient temperature is above 15 degree centigrade and the
workmanship is good following striking/deshuttereing period is considered
as safe.

26. What is the safe period to remove shuttering

27. Thank you