Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones

IJSTE - International Journal of Science Technology & Engineering | Volume 4 | Issue 5 | November 2017 ISSN (online): 2349-784X

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones Vinamra Bhushan Sharma PG Student Department of Civil Engineering GGITS, Jabalpur, India- 482003

Y. K. Bajpai Associate Professor & HOD Department of Civil Engineering GGITS, Jabalpur, India- 482003

Satyendra Dubey Assistant Professor Department of Civil Engineering GGITS, Jabalpur, India- 482003

Gourav Sachdeva Assistant Professor Department of Civil Engineering SRIT, Jabalpur, India- 482002

Abstract To find Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones. In India there are 4 seismic zones and several high rise multistory framed structures have been constructed now-a-days. For the structural behavior of framed structure, it is mandatory to analyze the behavior of structure for all possible conditions. In this work, total 48 models are taken into consideration and analyzed them to find out the behavior of RC framed structure for different seismic zones. Total three different soils types are taken as soft, medium and hard. G+4,G+5, G+6 & G+7 are taken of 15m, 18m, 21m & 24m respectively are considered in this work and analyzed for seismic zones II,III,IV & V. SMRF(Special Moment resisting Frame) is used for all 48 models. IS 1893-2002/2005 is used in STAAD PRO. (V8i) series 4 to analyze all models. This work consist of the analysis of framed structure for Maximum Node displacement (mm) in X direction for all soil types in various seismic zones. This is to configure the variation of Maximum Node Displacement for all types of heights and to find the most severe model among all. In this work steel framed structure can also be used instead of using RC framed structure. Height can also be extended beyond 24m for further research point of view.

Keywords: SMRF, Multistoried framed structures, Maximum Node Displacement, IS 1893-2002/2005) s, STAAD PRO, (V8i) series 4 ________________________________________________________________________________________________________ I.

INTRODUCTION

When earthquakes occur a building undergoes dynamic motion .This is because the building is subjected to inertia force that act in opposite direction to the acceleration of earthquake excitations. These inertia force called seismic loads. The purpose of this paper is to find maximum the node displacement for rigid supports under various zones considering differ soil types.

The present study is limited to RC multi-storied building in different zones II, III IV&V. The analysis is carried out the help of STAAD PRO. (V8i) series. The building model in the study has G+4,G+5,G+6& G+7 stories of 15m, 18m, 21m & 24m heights respectively. Three dimensional (3D) models of building were developed to analyze and compare the effect of seismic forces on multistory building by available computer program, STADD PRO. II. LITERATURE REVIEW There are many Research works has been done in the direction of seismic forces on multistory buildings.

V Ratna Priya and N jitendra Babu[1] analyzed building frame under various seismic zones considering flexible and rigid supports. They worked for vertical and lateral support reactions for rigid and flexible supports. Then they examined models for earthquake loadings.

They only worked for G+4 framed structures.

Sudhir K. Jain and R.K. Ingle [4] discussed Ductile Detailing of RC Building. The ductile detailing of structural members are considered which are listed below.

1) Beam Design of an RC Frame Building in Seismic Zone V, 2) Beam Design of an RC Frame Building in Seismic Zone II, 3) Interior Column Design of an RC Frame Building in Seismic Zone V, 4) Exterior Column Design of an RC Frame Building in Seismic Zone V etc.

5) They actually focused on all the points regarding shear force & moment in beam and axial force and moment in columns.

All rights reserved by www.ijste.org

53

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

For all seismic zones and soil conditions, there is not much work has been done much.

III. OBJECTIVE 1) 2) 3) 4)

Modeling of different building frames of different heights.

To work on STAAD PRO to analyze the structure.

To analyze the structure for different soil conditions i.e., soft, medium & hard.

To find node displacement –mm(x-direction) for various seismic zones.

IV. METHODOLOGY

This work is carried out to figure out the variation of values of node displacement for different heights.

Steps to carry out this task in STAAD Pro, are given below: Firstly go to Run Structure Wizard and select Bay Frame.

Then follow the following steps given below: It consist of 2 steps in this work which are:  MODELING  POST – PROCESSING Modeling: By using following steps the modeling of building frame can be done. The steps are: General  Properties General  Support General  Load & definitions And then assign them to structure Post-Processing: The results after modeling can be checked.

The below given table shows the data & dimensions used in analysis of work, Table – 1 Data & Dimensions Number of storey for different frames G+4, G+5, G+6 & G+7.

12m x 12m Plan size (Each grid size 3m x 3m) Size of columns 450mm × 450 mm Size of beams 300mm × 300 mm Wall thickness thick including Plaster 230mm Depth of slab 180 mm Height for different frames 15m,18m, 21m & 24m Floor to floor height 3.0m Grade of Concrete and steel M25 and Fe 415 Support condition Fixed Brick walls( outer and inner) 230mm & 115mm Seismic zones II, III, IV & V Soil conditions Soft, Medium & Hard

All rights reserved by www.ijste.org

54

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

V. RESULTS & DISCUSSIONS

Fig. 1: Model-I (Height: 15m)

Fig. 2: Model-II (Height: 18m)

Fig. 3: Model-III (Height: 21m)

All rights reserved by www.ijste.org

55

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

Fig. 4: Model-IV (Height: 24m)

For Seismic Zone: 2 Table - 2 Max. Node Displacement – Mm (X - Direction) MAX. NODE DISPLACEMENT – mm ( X - Direction )

SOIL CONDI TION

MOD EL-1

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

SOFT

12.83

-

-

MEDIU M

12.83

0

0

HARD

12.83

0

0

MOD EL-2

19.58 8 19.58 8 16.78 3

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

-

-

0

0

2.805

14.31

MOD EL-3

24.31 2 24.31 2 17.85 2

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

-

-

0

0

6.46

26.57

MOD EL-4

37.73 4 32.95 3 24.24

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

-

-

4.781

12.67

13.49

35.76

Fig. 5: Graph between Maximum Node Displacement & Model.

1) The maximum percentage of decreasing maximum node displacement (i.e., 35.76%) is found for Model-4 when compared hard soil strata with soft soil strata.

2) The values of maximum node displacement for Model-1 are same for all types of soil strata.

3) For Model-2, Model-3 & Model-4, the values of maximum node displacement are decreasing in hard soil strata when compared with soft soil strata & found the least for the same.

All rights reserved by www.ijste.org

56

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

For Seismic Zone: 3 Table – 3 Max. Node Displacement – mm (X - Direction)

SOIL CONDI TION

Soft Medium Hard

MO DEL1 20.51 1 20.51 1 20.51 1

DECRE ASED VALUE W.R.T. SOFT SOIL

MAX. NODE DISPLACEMENT – mm ( X - Direction ) % DECRE % DECRE % DECR ASED DECR ASED DECR MO MO EASE VALUE EASE VALUE EASE DELDELW.R.T. W.R.T. W.R.T. W.R.T. W.R.T. 2 3 SOFT SOFT SOFT SOFT SOFT SOIL SOIL SOIL SOIL SOIL

-

-

0

0

0

0

31.32 3 31.32 3 26.83 4

-

-

0

0

4.489

14.33

38.87 8 38.87 8 28.54 4

-

-

0

0

10.334

26.58

MO DEL4 60.35 2 52.70 4 38.76 2

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECR EASE W.R.T. SOFT SOIL

-

-

7.648

12.67

21.59

35.77

Fig. 6: Graph between Maximum Node Displacement & Model.

1) The maximum percentage of decreasing maximum node displacement (i.e., 35.77%) is found for Model-4 when compared hard soil strata with soft soil strata.

2) The values of maximum node displacement for Model-1 are same for all types of soil strata.

3) For Model-2, Model-3 & Model-4, the values of maximum node displacement are decreasing in hard soil strata when compared with soft soil strata & found the least for the same.

For Seismic Zone: 4

SOIL CONDI TION

Soft Medium Hard

MOD EL-1

30.75 2 30.75 2 30.75 2

DECRE ASED VALUE W.R.T. SOFT SOIL 0 0

Table – 4 Max. Node Displacement – mm (X - Direction) MAX. NODE DISPLACEMENT – mm ( X - Direction ) % DECRE % DECRE % DECRE ASED DECRE ASED DECRE ASE MOD VALUE ASE MOD VALUE ASE W.R.T. EL-2 W.R.T. W.R.T. EL-3 W.R.T. W.R.T. SOFT SOFT SOFT SOFT SOFT SOIL SOIL SOIL SOIL SOIL 46.96 58.30 9 1 46.96 58.30 0 0 0 0 0 9 1 40.23 58.30 0 6.734 13.47 0 0 5 1

MOD EL-4

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

90.51

-

-

11.47

12.67

32.38

35.78

79.03 7 58.12 5

All rights reserved by www.ijste.org

57

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

Fig. 7: Graph between Maximum Node Displacement & Model.

1) The maximum percentage of decreasing maximum node displacement (i.e., 35.78%) is found for Model-4 when compared hard soil strata with soft soil strata.

2) The values of maximum node displacement for Model-1 are same for all types of soil strata.

3) For Model-2 & Model-4, the values of maximum node displacement are decreasing in hard soil strata when compared with soft soil strata & found the least for the same.

For Seismic Zone: 5

SOIL CONDI TION

Soft Medium Hard

MOD EL-1

46.11 4 46.11 4 46.11 4

DECRE ASED VALUE W.R.T. SOFT SOIL 0 0

Table – 5 Max. Node Displacement – mm (X - Direction) MAX. NODE DISPLACEMENT – mm ( X - Direction ) % DECRE % DECRE % DECRE ASED DECRE ASED DECRE ASE MOD VALUE ASE MOD VALUE ASE W.R.T. EL-2 W.R.T. W.R.T. EL-3 W.R.T. W.R.T. SOFT SOFT SOFT SOFT SOFT SOIL SOIL SOIL SOIL SOIL 70.43 87.43 8 4 70.43 87.43 0 0 0 0 0 8 4 60.33 64.18 0 10.101 14.34 23.25 26.59 7 1

MOD EL-4

135.7 46 118.5 38 87.17

DECRE ASED VALUE W.R.T. SOFT SOIL

% DECRE ASE W.R.T. SOFT SOIL

-

-

17.2

12.67

48.57

35.78

Fig. 8: Graph between Maximum Node Displacement & Model.

All rights reserved by www.ijste.org

58

Seismic Behavior of Framed Structures with Different Soil Conditions and Different Seismic Zones (IJSTE/ Volume 4 / Issue 5 / 012)

1) The maximum percentage of decreasing maximum node displacement (i.e., 35.78%) is found for Model-4 when compared hard soil strata with soft soil strata.

2) The values of maximum node displacement for Model-1 are same for all types of soil strata.

3) For Model-2, Model-3 & Model-4, the values of maximum node displacement are decreasing in hard soil strata when compared with soft soil strata & found the least for the same.

VI. CONCLUSIONS 1) As the height of the building frame is increases the values of maximum node displacements are increases.

2) For maximum node displacements, Seismic Zone-2, Seismic Zone -3 & Seismic Zone -5 shows almost same increase in percentages.

3) In Seismic Zone - 2, Seismic Zone - 3 & Seismic Zone – 5: For Model-2, Model-3 & Model-4, the values of maximum node displacement are decreasing in hard soil strata when compared with soft soil strata & found the least for the same.

4) For Seismic Zone- 4: In Model-3 , there is no variation in maximum node displacement among soft, medium & hard soil strata.

REFERENCES [1]

V Ratna Priya and N jitendra Babu,(2017), Seismic reaction of building frame under various zones considering flexible and rigid supports, IJCIET, Volume 8, Issue 1.

[2] Girum Mindaye and Shaik Yajdani, (2001),Seismic Analysis of a Multi-storey RC Frame Building in Different Seismic Zones , IJIRSET, Volume 5, Issue 9.

[3] Ashis Debashis Behera, K.C. Biswal “3d Analysis Of Building Frame Using Staad Pro.” NIT ROURKELA [4] Dr. Sudhir K Jain (IIT Kanpur) and Dr. H.J.Shah (M.S.University of Baroda, Vadodara) “Design Example of a Six Storey Building” IITK-GSDMA-EQ26V3.

[5] Dr. Sudhir K Jain (IIT Kanpur) and Dr. R.K. Ingle (VNIT, Nagpur) “ Explanatory Examples For Ductile Detailing Of RC Building” IITK-GSDMA-EQ22V3.0 [6] IS: 456-2000(Indian Standard Plain Reinforced Concrete Code of Practice)– Fourth Revision [7] IS: 1893-2002 (part-1) “criteria for earthquake resistant design of structures” fifth revision, Bureau of Indian Standards, New Delhi.

[8] IS: 875-1987 (part-2) for Live Loads or Imposed Loads, code practice of Design loads (other than earthquake) for buildings and structures [9] P. C. Varghese, Advanced Reinforced Concrete Design, Second Edition.

[10] N. Krishna Raju - “Advanced Reinforced Concrete design”

All rights reserved by www.ijste.org

59