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International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 6, June 2017, pp. 398–410, Article ID: IJCIET_08_06_044 Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=6 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed

COMPARATIVE STUDY ON THE EFFECT OF

LATERAL STIFFNESS ON DIFFERENT

STRUCTURAL FRAMING SYSTEMS

SUBJECTED TO LATERAL LOADS

Sheethal Mary Jose

PG Student, Manipal Institute of Technology, Manipal University, Manipal, India

Asha U Rao

Associate Professor (Sr. Scale), Manipal Institute of Technology, Manipal University, Manipal, India

Dr. Abubaker KA

Baker Associates and Consultants, Cochin, India

ABSTRACT

In general the overall response of a building subjected to lateral loads like wind

load and earthquake load increases with the increase in height of the building. Lateral

load resisting systems are usually provided to reduce or decrease the load effect. The

resistance may be offered by Frame Action, Core Walls, or combined Walls and

Frames (also known as Dual System). In this study, 3D structural modeling based

software STAAD. Pro V8i will be used to generate and analyze three-dimensional

building models for the assessment of the relative effectiveness of the lateral load

resisting systems under the effect of wind load and earthquake load and the maximum

lateral displacement at the top storey is checked. The purpose of my research is to

compare the stiffness of different structural framing system. Also to find out if we can

neglect the presence of walls (concrete or masonry) if they are together with the frame

system, where the frame system resists all the lateral shear forces and the walls will be

considered just to bear the vertical load, and what are the provisions for these walls

and their effect on the frames load. Ten types of RC frames including a bare frame,

frames with external infill of 230mm thick, 150mm thick, 115mm thick and frames with

both internal and external infills of 115 mm and 230 mm respectively with and without

Staircase and Core wall have been considered. Number of storey has been G+29.

Each model has been analyzed for the calculation of lateral displacement at the top

story. From the study conclusion has been done in the frame analysis considering the

stiffness of different elements i.e. staircase, core walls and infill walls which shows

significant variation in the lateral displacement and graphs have been plotted.

Comparative Study on The Effect of Lateral Stiffness on Different Structural Framing Systems Subjected to Lateral Loads


Index Terms: High Rise Building; Core Walls; Infill Walls; Lateral Loads; Lateral Displacement.

Cite this Article: Sheethal Mary Jose, Asha U Rao, Dr.Abubaker KA Comparitive Study on The Effect of Lateral Stiffness on Different Structural Framing Systems Subjected to Lateral Loads. International Journal of Civil Engineering and

Technology, 8(6), 2017, pp. 398–410. http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=6

1. INTRODUCTION

A multi-story building is said to be tall, when the response becomes significantly high such that the effect of lateral load should also be considered in the design of the structure. Tall buildings are prone to excessive displacements. The lateral load effects on buildings can be resisted by Frame action, Shear Walls, or Dual System. The two parameters that are being used for evaluating the stiffness and lateral stability of lateral force resisting systems of high rise buildings are

1. Lateral Displacement (side sway).

2. Peak inter-story drift.

The types of structural systems for resisting wind and seismic loads are called Shear systems such as:

a) Frames

Framed system of rigid beams are subjected to lateral loads where no moments have been developed at the centre of columns and the shear forces are distributed proportionally with the moment of inertia of the columns and the lateral displacements developed will be proportional to shear forces developed.

b) Shear walls

Framed systems with the shear walls resist the lateral loads whether these walls are connected or separated by beams. Shear forces are distributed proportionally with the moment of inertia of the cross sections of the walls; flexural deformations in the walls results in the displacements in each floor or level.

c) Dual systems

In dual systems to resist the lateral load two latter systems are being combined. Main advantage of this combination is that the frames support the walls at the top and control their displacement and the walls support the frames at the bottom and decrease their displacement.

And the purpose of this research is to find out if the presence of walls (concrete or masonry) can be neglected if they are together with the frame systems where all the lateral shear forces are being resisted by the frame system and the walls are considered just to bear the vertical load, and the provisions for these walls and their effect on the frames load.

2. EFFECT OF LATERAL LOADS ON TALL BUILDINGS

Generally if the ground is subjected to some kind of movement, the building is thrown backwards and the roof is subjected to a force known as Inertia Force..In order to transfer the Inertia Forces in a safe manner, all the structural elements and their connections should be designed in such a way that safe transfer of these forces occurs safely through them. In transferring Inertia Forces walls or columns are the most critical elements. But in traditional type of construction, Floor slabs and beams are being taken into consideration during design

Sheethal Mary Jose, Asha U Rao and Dr. Abubaker KA


and construction than columns and walls. Walls are generally made of masonry which is brittle in nature and are relatively thin and along the direction of their thickness, wall are very poor in carrying the inertia forces generated due to horizontal earthquake. The columns which are designed poorly and constructed are disastrous. In general, lighter buildings can withstand the earthquake shaking better when compared to high rise buildings

3. METHODOLOGY

A. Model Specifications

Building Type: High rise RC frame

Storey Height: 3m

Floor area: 59.20m x 18.73m

No. of Stories: G+29.

• Modelling has been done for bare frame, frame with stair case and core wall (with and without infill wall of various thicknesses), frame with infill wall of various thicknesses subjected to lateral loads.

• Comparison has done for Lateral displacements of frames with and without consideration of core wall & Staircase, having infill walls of different thicknesses.

B. Material Properties

• Reinforced concrete with M-30 grade concrete and fe-415 grade reinforcing steel were the materials used for the study.

• As per IS 456:2000 The Stress-Strain relationship has used. The material properties used are as follows:

• Modulus of Elasticity of steel, Es = 21, 0000 MPa

• Yield stress for steel, fy = 415 Mpa

• Ultimate strain in bending, Ƹcu =0.0035

• Characteristic strength of concrete, fck = 30 MPa

C. Modelling Of Structures

Ten types of RC frames with and without Staircase and Core wall have been considered; a bare frame, frames with external infill of 230mm thick, 150mm thick, 115mm thick, frames with external infill of 230mm and internal infill of 115mm thickness. Number of storey has been G+29. The overall plan dimension of RC frame structures is 59.20m x 18.73m. The storey heights are taken as 3m and all the buildings are assumed to be fixed at the ground level. An RCC slab of 120mm thickness has been considered and all the members of the structure are assumed to be homogeneous, isotropic having elastic modulus same in compression as well as in tension, details are shown in Table 1

Table 1: Section details

Member Size (mm)

Plinth Beams 200 X 450 Floor & Roof Beams 200 X 600 Columns 300 X 1200 External Walls 230, 150, 115 Slab 120



D. Building Nomenclature

Nomenclature of the models adopted for analysis is given in Table 2.

Table 2: Building Nomenclature

S.No Type of model Without Staircase &

Core wall

With Staircase &

Core wall

1 Bare Frame BF BFSC 2 Frame with external infill of 230 mm EX230 EX230SC 3 Frame with external infill of 150 mm EX150 EX150SC 4 Frame with external infill of 115 mm EX115 EX115SC 5 Frame with external infill of 230 mm

& internal infill of 115 mm EX230IN115 EX230IN115SC

A typical plan of BFSC is shown in Figure. 1, three dimensional view of BFSC is given in Figure. 2 and for EX230SC is given in Figure. 3

Figure 1 Plan of building BFSC

Figure 2: 3-D view of model BFSC Figure 3. 3-D view of model EX230SC



4. RESULTS AND DISCUSSIONS

A) RC Framed Structures with Different Stiffness Configurations

Case 1: Bare Frame

• The columns are of 300mm x 1200mm size, plinth beams are of 200mm x 450mm, floor & roof beams are 200 x 600mm and size 120mm thick Slab is considered on the all floors & Roof.

• Self-weight, live load, wall loads, slabs Loads, Wind loads and Earthquake loads are considered.

• The structure is analysed for Static analysis.

Figure 4 Lateral Displacement Vs Height for Bare frame

From Figure 4, it is observed that the maximum displacement of 720.714mm occurs at top storey of the building (i.e., 90m level) and it does not satisfy the requirement of permissible lateral displacement (i.e., H/500, H = Height of structure) as per IS 456:2000.

Case 2: Frame with Staircase and Core Wall Only.

• The columns are of 300mm x 800mm size, plinth beams are of 200mm x 450mm, floor & roof Beams are 200 x 600mm and size 120mm thick Slab is considered on the all floors & Roof.

• The Staircase is 4.20m x3.29m and Core wall is 230mm thick.



Figure 5 Lateral Displacement Vs Height for Frame with Core Wall & Staircase

From Figure 5, it is observed that the maximum displacement of 436.569mm occurs at top storey (i.e., 90m level) and it does not satisfy the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.



Case 3: Frame with Only External Infill of 230 mm Thick.


• The External infill of 230mm thickness is provided.



Figure 6 Lateral Displacement Vs Height for frame with only External infill of 230mm thick

From Figure 6, it is observed that the maximum displacement of 182.626mm occurs at top storey (i.e., 90m level) and it does not satisfy the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.

Case 4: Frame with Staircase, Core Wall and External Infill of 230 mm Thick.



• The External infill of 230mm thick provided.



Figure 7 Lateral Displacement Vs Height for Frame with Staircase & Core Wall External infill of 230mm thick



From Figure 7, it is observed that the maximum displacement of 132.749mm occurs at top storey (i.e., 90m level) and it satisfies the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.






Figure 8 Lateral Displacement Vs Height for frame with only External infill of 150mm thick

From Fig 8, it is observed that the maximum displacement of 164.448mm occurs at top storey (i.e., 90m level) and it satisfies the requirement of permissible (i.e., H/500, H =Height of structure) lateral displacement as per IS 456:2000









Figure 9 Lateral Displacement Vs Height for Frame with Staircase & Core Wall and External infill of 150mm thick

From Fig 9, it is observed that the maximum displacement of 128.067mm occurs at top storey (i.e., 90m level) and it satisfies the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.






Figure 10 Lateral Displacement Vs Height for frame with only External infill of 115 mm thick





• The External infill of 115mm thick is provided.

0

20

40

60

80

100

0 20 40 60 80 100 120

Hei

gh

t (m

)

Lateral Displacement (mm)

EX230IN115





Figure 11 Lateral Displacement Vs Height for Frame with Staircase & Core Wall and External infill of 115mm thick

From Fig 4.11, it is observed that the maximum displacement of 125.78mm occurs at top storey (i.e., 90m level) and it satisfies the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.

Case 9: Frame with External Infill of 230 mm Thick and Internal Infill of 115 mm Thick.


• The External infill of 230mm thick and internal infill of 115mm thick is provided.



Figure 12 Lateral Displacement Vs Height for frame with only External infill of 230mm thick and Internal Infill of 115mm thick.


0

20

40

60

80

100

0 20 40 60 80 100 120

Hei

gh

t (m

)


EX230I…

0

20

40

60

80

100

0 20 40 60 80 100 120

Hei

gh

t (m

)


EX230I…



Case 10: Frame with Staircase, Core Wall and External Infill of 230 mm Thick and

Internal Infill of 115 mm Thick.


• The External infill of 230mm thick and Internal Infill of 115mm thick are provided.



Figure 13 Lateral Displacement Vs Height for frame with Staircase, Core wall External infill of 230mm thick and Internal Infill of 115mm thick.

From Fig 13, it is observed that the maximum displacement of 75.13 mm occurs at top storey (i.e., 90m level) and it satisfies the requirement of permissible (i.e., H/500, H = Height of structure) lateral displacement as per IS 456:2000.

5. COMPARISONS

Comparison. 1

Table 3 Comparison between Bare Frame and Frame with External infill of 230 mm thickness & Internal infill of 115 mm thickness.

Type of Model Maximum

lateral

displacement

(mm)

Permissible

lateral

displacement

(mm)

Percentage of

variation in lateral

displacement w.r.t to

BF

Bare Frame (BF) 720.714 180

86.6 Frame with External infill of 230 mm thickness and Internal infill of 115 mm thickness (EX230IN115)

96.57

180

From Table 3 it is observed that, there is a reduction in percentage of variation in lateral displacement of 86.6 % at top storey, while comparing with the bare frame.

0

20

40

60

80

100

0 50 100 150

Hei

gh

t (m

)


EX230…



Figure 15 Comparison of Lateral displacement Vs Height for Bare frame (BF) and Frame with External infill 230mm &Internal infill 115mm (EX230IN115)

Comparison 2

Table 4 Comparison between Bare Frame (BF) and Frame with Staircase & Corewall (BFSC).


lateral

displacement

(mm)

Permissible

lateral

displacement

(mm)

Percentage of variation

in lateral displacement

w.r.t to BF


39.42

Frame with Staircase & Corewall (BFSC)

436.569 180

From Table .4, observed that, there is a reduction in percentage of variation in lateral displacement of 39.42 % at top storey, while comparing with the bare frame.

Figure 16 Comparison of Lateral displacement Vs Height for Bare frame (BF) and Frame with Staircase and Core wall (BFSC).

0

20

40

60

80

100

0 200 400 600 800

Hei

gh

t (m

)


BF

EX230IN115

0

20

40

60

80

100

0 200 400 600 800

Hei

gh

t (m

)


BF

BFSC



Comparison 3

Table 5 Comparison between Bare Frame (BF) and Frame with External infill of 230 mm thickness, Core wall & Staircase (EX230SC).


lateral

displacement

(mm)

Permissible

lateral

displacement

(mm)

Percentage of

variation in lateral

displacement w.r.t

to BF


81.58

Frame with External infill of 230 mm thickness, Staircase & Core wall (EX230SC)

132.749

180

From Table 5, observed that, there is a reduction in percentage of variation in lateral displacement of 81.58 % at top storey, while comparing with the bare frame.

Figure 17 Comparison of Lateral displacement Vs Height for Bare frame (BF) and Frame with Staircase and Core wall (EX230SC).

6. CONCLUSIONS

The lateral displacement of R.C framed structure with and without considering Staircase, Core wall & infill walls have been investigated using the static analysis. Following were the major conclusions drawn from the study.

• The lateral displacement in Bare frame (BF) is observed to be the highest and Frame with External infill of 230 mm thickness and Internal infill of 115mm thickness , Staircase and Corewall (EX230IN115SC) is observed to be the case with minimum lateral displacement among the ten lateral load resisting systems that were investigated.

• For all the models that have been taken into consideration, the values of story lateral displacements are within the permissible limits as per codal provisions except for Bare Frame (BF) and Frame with staircase & core wall (BFSC). However, it is observed that there was a considerable variation in the lateral displacement of frame with staircase & core wall when compared with bare frame.

• There is a reduction in percentage of variation in later displacement of 86.6% at top storey (i.e., 90m level) of frame with staircase, core wall and external infill 230mm thick and Internal infill 115mm thick (EX230IN115) when compared with bare frame (BF).

• It can be concluded in such a way that, consideration of stiffness of different elements (i.e., staircase, corewall and infill walls) in the frame analysis shows significant variation in the lateral displacement.

0

20

40

60

80

100

0 200 400 600 800

Hei

gh

t (m

)

Lateral displacement (mm)

BF

EX230SC



REFERENCES

[1] Karl Hermann Mathias., Bjornland (2013) “Wind-induced Dynamic Response of High Rise Buildings” Journal of Structural Engineering, ASCE, Volume 111, No. 11.

[2] P. Mendis, T. Ngo., N. Haritos. and A. Hira (2007) “Wind Loading on Tall Buildings”EJSE Special Issue: Loading on Structures (2007).

[3] D. Boggs and J. Dragovich (2003) “The Nature of Wind Loads and Dynamic Response” Eng. Struct., 29 11 2641–2653.

[4] Lawrence G. Griffis (2008) “Serviceability Limit States Under Wind Load” Engineering Journal / American Institute Of Steel Construction.

[5] Ámundi Fannar Sæmundsson (2007) “Wind effects on high rise buildings” Journal of Wind Engineering and Industrial Aerodynamics, 36.

[6] Masoud Sanayei, Lewis Edgers, Joseph Alonge& Paul Kirshen (2003) “Effects of Increase Wind Loads on Tall Buildings” Civil Engineering Magazine, ASCE.

[7] J. Lavado, M.L. Gonzalez, (2004) Influence of Stair Slabs in Reinforced Concrete Buildings under Seismic Loads", in B.H.V. Topping, C.A. MotaSoares, (Editors), "Proceedings of the Seventh International Conference on Computational Structures Technology", Civil- Comp Press, Stirlingshire, UK, Paper 273, 2004. doi:10.4203/ccp.79.273

[8] Mohd Danish, Shoeb Masood and Zaid Mohammad (2013) “Performance of Masonry Infill in RC Frame Structures” 2nd International Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013 College of Engineering, Teerthanker Mahaveer University.

[9] Hideo Takabatake (2000) “A Simplified Analytical Method for High-Rise Buildings” Proc., 11th Int. Conf. on Wind Engineering, 2381–2388.

[10] Guoqing Huang, Xinzhong Chen (2007) “Wind load effects and equivalent static wind Loads of tall buildings based on synchronous pressure measurements” Engineering Structures 29 (2007) 2641–2653.

[11] Tashi Dorji Tamang, Visuvasam J and Simon J, Effect of Infill Stiffness on Seismic Performance of Moment Resisting RC Structure. International Journal of Civil Engineering and Technology, 8(3), 2017, pp. 1023–1033.

[12] Ashok Shaji and N. Lokeshwaran, Comparative Analytical Investigation of 2D Steel Frames Subjected To Lateral Load Using Steel Cable Bracing. International Journal of Civil Engineering and Technology, 8(4), 2017, pp. 734–743.

[13] I. Jaswanth Reddy and S. Kesavan, Lateral Load Behaviour of Interlocking Block Masonry Wall. International Journal of Civil Engineering and Technology, 8(3), 2017, pp. 831–841.

[14] Edoardo Cosenza, Gerardo Mario Verderame and Alessandra Zambrano Seismic (2008) “Performance of Stairs in the Existing Reinforced Concrete Building” World Conference On Earthquake Engineering October 12-17, 2008, Beijing, China.

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