Architecture & Civil Engineering

Architecture & Civil Engineering


Pages: 11  ,  Volume: 40  ,  Issue: 1 , November   2019
Received: 16 Nov 2019  ,  Published: 20 November 2019
Views: 163  ,  Download: 71


# Author Name
1 Dipa Sarker
2 Ariful Islam
3 Mirajul Alam
4 Mohammad Arman Ullah


The flat plate system has been adopted in many buildings in Bangladesh specially in garments factory buildings. However,
it is observed that extra cantilevers sides which are not conforming to the actual plan and design are constructed to take
advantage of the extra floor space to meet the economical demands. Many structures in Bangladesh differ from their
actual plan due to the extra cantilever portion provided by the developers. So the various effects that take place in the
building due to this phenomenon are discussed in this research. The axial force, deflection, punching shear, horizontal &
vertical displacement of columns has been analyzed for increasing cantilever of 2ft, 4ft, 6ft, 8ft and 10 ft respectively.
Deflection at mid-point of a panel of a particular slab, column strip and middle strip are also determined. Percentage of
increase in column load for 2ft, 4ft, 6ft, 8ft & 10 ft is compared and their variability is observed. Factor of safety is OK for
a structure with no cantilever. For 2 ft. extra cantilever, the exterior column fails. For 4ft, 6ft, 8ft & 10ft, the factor of
safety for exterior and corner column is unsafe and thus fails. But it does not affect much to the interior columns and they
are found safe in every condition. It has been observed in all cases that corner and exterior columns are more susceptible
to extra cantilevers than interior column. According to the punching shear check, no shear reinforcement is required for
corner column and exterior column. Flat plates are also used by the engineers because it provides more space and stability.
Structural engineers commonly use manual calculations for the analysis of flat plate structures. The software STAAD.Pro
V8i has been used in this paper for the design and analysis of a six storied garments factory building. For the analysis, 3
load combinations are used in this paper. To understand the structural behavior of the slab due to increase in the cantilever
portion of the slab, different parameters are evaluated using the software. The manual calculations for axial force,
horizontal and vertical displacements, deflection and punching shear are also performed in order to compare them with the
results obtained from STAAD Pro. The obtained results are plotted against the various load combinations for a graphical
representation of effect of structural behavior of the columns and slabs. The analysis is done for a concrete structure and
slab thickness is also defined as per calculation.


  • extra cantilever
  • structural behavior
  • STAAD.Pro V8i
  • References

    Ahmed, F., Kumar, B., Chandrashekhar,Y. (2012) Comparative Analysis of Flat Plate Structures Under wind load, International Journal
    of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-2, Issue-1, October 2012
    Borges, L. Guilherme, S. and Gomes, B. (2013) Punching Shear of reinforced flat plates with openings, ACI Structural Journal/JulyAugust 2013
    Charlebois, K.(2011) Structural Design of a cantilevered building
    Cheng, M. (2009) Punching shear strength and deformation capacity of fiber reinforced concrete slab-column connections under
    earthquake type loading.
    Erberik, M. and Elnashai, S.(2003) Seismic Vulnerability of Flat Plate Structures Mid-Americana Earthquake Center DS-9 Project(Risk
    Assessment Modelling) University of Illinois at Urbana-Champaign
    Lelekakis, S. George E., Birda , Athina T., Mitoulis, Stergios A (2006) Application of Flat Plate Structures in seismic regions, Aristotle
    University of Thessaloniki, Department of Civil Engineering,
    Moehle, J., Diebold, W. and Zee, H.(2004) Experimental Study of a Flat Plat Building Model
    Nilson H. A., Darwin D., Dolan W. C., 2010-2011, “Design of Concrete Structures.”(Thirteenth Edition), McGraw Hill
    Richard, M. (1996) Shear flow past flat plates
    Song, J. and Kim, J.(2012) Effective punching shear and moment capacity of flat plate-column connection with shear reinforcements for
    lateral loading. International Journal of Concrete Structures and Materials Vol.6, No.1, pp.19~29, March 2012
    Shin, Woo-seung (2013) Seismic Retrofit of flat plate structures, 1CS Structural Engining Inc., Sungnam 462-807, Korea
    World Academy of Science, Engineering and Technology Vol:3 2009-11-21