Abstract:
It is known that the ultimate strength and carrying capacity of columns depends on
pattern of loading, cross-sectional shape of columns, diameter of reinforcement, and
cross-sectional area of the columns. Hollow-core systems are cost effective, allow
construction to remain on budget and on schedule, require less maintenance, and create
less environmental impact than conventional building materials. Hollow core columns
having circular holes shall be better performance as it creates smooth configuration to
cross-section of columns.
The behavior of reinforced concrete columns with holes under axial load is not
understood, and researches in the subject are needed to help designers and structural
expert officials. Holes drilled out to install additional services or equipment, such
as ducts through columns, beams, or walls, can lead to loss of strength and possible
structural failure. Until now little work has been done on effect of holes in columns and,
hence, this study aims to examine the amount of capacity and strength lost due to the
presence of holes in columns. Nonlinear finite element analysis on 14-columns (7-
squares; 7-rectangulars) specimens is conducted by using ABAQUS software. The
nonlinear finite element analysis program ABAQUS is used owing to its capabilities to
predict either the response of reinforced concrete columns in the post-elastic range or in
the ultimate strength range of reinforced concrete columns. An extensive set of
parameters is investigated including; dimensions of the holes with diameter of (20mm,
50mm), and different relative position of the holes in the columns. The shapes of holes are
circular for both columns.
The carrying capacity and ultimate strength of reinforced concrete short-braced columns
with different position of longitudinal openings are discussed in the lesson of study. The
effect of the electric wiring through the columns with help of ducts are adequately
assessed under the effects of axial loading; because the structural response of the
members with a hole under pure axial loading may be significantly different from that of
solid column due to existence of avoid section.
In conclusion, the analysis result shows significant reduction in load carrying capacities
for both square and rectangular columns with duct of wiring compare to their respective
solid columns due to reduction of their effective cross-sectional area. The study also
reveals that, square columns are sensitive in reduction of capacity than rectangular
columns of the same size of the holes at the same position in the columns cross-section.
For instance, the peak reduction for rectangular column is 5.55 % (case-d) and 7.75 %
(case-d) for square columns compare to their respective control specimens.
