Review of Analysis of Irregular Building

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Review of Analysis of Irregular Building

Jerin Mathew Jose1, Kesiya Josy V2, Likhith Koruthe Varghese3, Nayana P P4

1,2,3,4UG Students, Department of Civil Engineering Mangalam College of Engineering, Kottayam,India

Adithya Viswambaran5

5Assistant Professor, Department of Civil Engineering Mangalam College of Engineering,

Kottayam,India

AbstractThis paper deals with the review of structural behavior of irregular building for different plans like rectangular,C,L and I shape. Modeling of 15- stories RCCframed building to be a done on the ETABS software for analyze. maximum shear forces, bending moments, and maximum story displacement are computed and then compared for all the analyzed structure.

Keywords: – Irregular building, ETABS software, shear force, story displacement,story drift.

  1. INTRODUCTION

    ETABS provides both static and dynamic analysis for a wide range of gravity, thermal and lateral loads. Dynamic analysis may include seismic response spectrum or accelerogram time history. This analysis mainly deals with the study of a rectangular, L, C and I shaped plan using ETABS.

    The behaviour of any building depends on the arrangement of structures present in it.Irregularity in structures is alack of symmetry or eccentricity between geometry,mass,stiffness etc.Irregularities are introduced in real design for both aesthetic and utility.Irregularities in the distribution of mass, stiffness, and geometry along the height of the building grouped as vertical irregularities.The system having physical discontinuityis termed as irregular building.

    A 32m x 24m 15- stories structure having 4m x 4m bays are modeled using ETABS. The height of each story is taken as 3m, making the total height of the structure 45m. Loads considered are accepted by the IS-875(Part1, Part2), IS- 1893(2002) code,and combinations are acc. to IS-875(Part5). Analysis of the structure, maximum shear forces, bending moments, story drift, and maximum story displacement, are computed and then compared for all the analyzed system.

  2. LITERATURE REVIEW

    Abhay guleria studied the structural analysis of multi-storey irregular building with different plans. It emphasizes on the structural behavior of multi-storey buildings for different plan configurationslikerectangular, C, L, and I shape. Help to give an idea about the story overturning moment varies inversely with storey height. Dynamic analysis, mode shapes are generated, and it can be asymmetrical plans undergo more deformation thansymmetricalplans. Modeling is to be done by using this journal.

    SIVA NAVEEN E (2018) also studied the dynamic analysis of irregular buildings under earthquake loads.The structural behavior of multi -story frames with single and combination of irregularities.Help incorporating abnormalities in structures without compromising their performance the regular and irregular models. The Idea about the response spectrum analysis was conducted to clarify these models by taking the results of maximum displacement, inter-story drift, and story shear to compared. Response spectrum method allows a clear understanding of the contribution of different modes of plans.It is also useful for approximate evaluation of seismic reliability of structures.

    From the above papers the problem, was learnt, analyzed and solved. Thispaper, focused on the dynamic analysis of an irregular buildings using grid slabs for different plan configurations. The topic which we are doing has very few articlespublished

  3. METHODOLOGY

    A. Modelling of RCC frames

    An RCC framed structure is an assembly of slabs, beams, columns, and foundations inter-connected to each other, as a unit. The load transfer mechanism in these structures is from slabs to rays, from beams to columns, and then,ultimately, from columns to the foundation, which in turnpasses the load to the soil. In this study, we have adopted four cases:

    1. Rectangular Plan

    2. L-shape Plan c)I-shape Plan

    1. C-shape Plan

      Fig. 1: Plans of buildings

      The building is 32m x 24m in plan with columns spaced at 4mfrom center to center. A floor-to-floor height of 3m is assumed.

      TABLE1

      Building Description

      Length x Width

      32mmx24mm

      No. of stories

      15

      Story height

      3m

      Beam dimensions

      450mmx450mm

      Column 1-5 stories dimensions

      600mmx600mm

      Column 6-12 stories dimensions

      500mmx500mm

      Slab thickness

      125mm

      Thickness ofthe main wall

      230mm

      Thickness of the parapet wall

      115mm

      Support conditions

      Fixed

      TABLE 2

      Material Specifications

      Grade of Concrete

      M30 fck= 30N/mm2

      Grade of Steel

      fy= 415N/mm2

      TABLE 3

      Loads

      PARAMETERS

      DETAILS

      Dead load

      15.87kN/m2

      Live load

      8 kN/m2

      Seismic zone

      V

      Soil type

      I

      Importance factor

      1

      Response reduction factor

      5

      Damping

      5%

      Codes

      IS 875 (part 1)

      IS 875 (part 2)

      IS 875 (part 5)

  4. RESULTS

    TABLE 4

    Story displacement

    The above table shows that the story displacement increaseswith the increase in story.

    Fig.2 Displacement diagram

    The above graph, it represents the graphical representation of the story displacement with different stories.

    Shear force

    Fig. 3 shear force diagram

    As per the above figure it has been concluded that the story shear decreases with the increase in story height.

    Story drift

    Fig.4 story drift diagram

    The above graph, it represents the graphical representation of story drift with various heights. It increases initially and decreases with increasing the height.

    The above results show that, the displacement of building is increased with increasing the height but the shear force is decreased with increasing height and the story drift increasing

    with increasing the height and reach the maximum point and slowly decreased with increasing the height.

  5. CONCLUSIONS

Dynamic analysis, mode shapes are generated and it can be concluded that asymmetrical plans.

    • Validation of the software has been done by selecting suitable journal

    • Comparison of modal mass participation ratios was done usingETABS software. A very less variation was found

    • Comparison of story displacement values resultedin

      0.35 variation

    • The comparison of story drift value resulted in the difference of 1.27mm

    • The story shear results we obtained were nearly 2800kN.

TABLE 5

COMPARISON OF RESULTS

Parameters

Journal

ETABS

Story displacement

32.39

32.04

Story shear

2876.87

/td>

2865.65

Story drift

9.5

10.77

The above table shows that the difference between journal structure and analytical structure.

REFFERENCES

  1. Poonam, Anil Kumar and A. K. Gupta, Study of Response ofStructural Irregular Building Frames to Seismic Excitations,International Journal of Civil, Structural, Environmental andInfrastructure Engineering Research and Development, Vol.2,Issue 2 (2012) 25-31

  2. B. K. Sanghani and P. G. Patel, Behaviour of BuildingComponent in Various Zones,International Journal of Advancesin Engineering Sciences, Vol. 1, Issue 1(Jan. 2011)

  3. P. Prashanth, S. Anshuman, R.K. Pandey, Herbert Arpan,Comparison of design results of a Structure designed usingSTAAD and ETABS Software, INTERNATIONAL JOURNALOFCIVIL AND STRUCTURAL ENGINEERING, Volume 2, No3, 2012

  4. Salahuddin Hammad, Habib Saqib, Rehman Talha, Comparisonof design of a building using ETABS V 9.5 & STAAD PRO,2005

  5. Bureau of Indian Standards: IS-875, part 1 (1987), Dead Loads onBuildings, and Structures, New Delhi, India.

  6. Bureau of Indian Standards: IS-1893, part 1 (2002), Criteria forEarthquake Resistant Design of Structures: Part 1 GeneralProvisions, and Buildings, New Delhi, India.1485

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