Page 45 - ICJ Jan 2023

TECHNICAL PAPER COLLECTOR’S EDITION

Specimen Cracking stage Ultimate stage P um Type of TPercentage Percentage
failure ultimate ultimate
Lo.cation Cracking Ultimate Location P cr load load as
of load load with solid per IS code
first crack P cr P um beam

B 3 Opening 3.9 9.0 Midspan 2.3 Flexure 99 115
B 4 Opening 3.5 6.0 Opening 1.7 Shear 66 115

B 5 Opening 4.5 8.0 Opening 1.8 Shear 88 142
Secondary
hinging
mechanism

B 6 Midspan 2.5 8.0 Opening 3.2 Flexure 88 138
(11.5)* (126)*
B 7 Midspan 4.5 11.5 Midspan 2.5 Flexure 126 119

B 8 Midspan 5.0 13.8 Opening 2.8 Flexure 151 140
B 9 Midspan 4.5 9.1 Midspan 2.0 Flexure 100 80

(v) Trimming opening with reinforcement does 2. Gene Corley, W., Parmelee, Hanson. M., and
not have any effect either on ultimate capacity Barney. B., -Behaviour and design of prestressed
or crack pattern. concrete beams with large web openings’. PCI-
(vi) Vertical strrrups and hooks provided adjacent Journal November/December 1977. Vol 22. pp.
to openings contain cracking. 32-61.
(vii) Compressive struts and tensile struts carry 3. Abdus Salam and Jack Harop.. ‘Prestressed
the external shear in proportion to their cross- concrete beams with transverse circular holes’,
sectional areas. Journal of the SIntetural Division. ASCE, March
(viii) Deflections of beams with openings are well 1979, pp. 635.
within those allowed by the I.S. codes: the
4. Nasser. W.. Acavalos. A and Daniel. H. R..
influence of openings on deflection is minor
‘Behaviour and design at large openings in
in properly reinforced beams.
Reinforced concrete beams’. ACI- Journal, January
References 1967. Vol 64, pp. 25-33.

1. Ragan. H. S.. and Warwaruk. J. ‘Tee members with 5. Barker. M., ‘Discussion on behaviour and design
large web openings. PCI-Journal . August 1967, of large opening in reinforced concrete beam’,
Vol. 12 pp. 52-65. ACI-Journal, July 1967, Vol 64, pp. 418422.

V. Dinakaran, Consulting Engineer. Bangalore.
M. K. L. N. Sastry. Faculty of Civil Engineering, Bangalore University, Bangalore

46 The Indian Concrete Journal | November 2018