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SEISMIC PERFORMANCE OF HIGH-RISE BUILDING USING OUTRIGGER AND

DIAGRID STRUCTURAL SYSTEM

MUSTAFA HUSSAINI1 & SANDEEP NASIER2

1Structural Engineering, Department of Civil Engineering, Chandigarh University, Punjab, India

2Assistant Professor, Department of Civil Engineering, Chandigarh University, Punjab, India

ABSTRACT

From ancient times humans were interested in building structures high, and this was grown by revaluation of

technology in 19th century. After revaluation of technology peoples tried to move from urban lives towards cities for

seeking jobs and life opportunities, in this way cities were over populated and the need for high-rise building was

growing day by day because of lack of available land. But as height of structures increases lateral loads govern the

design of structure. To tackle lateral loads in high-rise buildings there are number of lateral load resisting system

without adding to the tonnage of the building or increase its plan dimension. Outrigger is one of the lateral load

resisting structural systems that can be used. Outrigger system build by a core shear wall and belt truss and outrigger

trusses in order to build the structure laterally stiff and increase its strength. Diagrid is another lateral load resisting

that is newly developed mechanism. Diagrid system attracted the interest from both architects and designers because of

its ability to resist lateral load and gravity load at the same time. Diagrid system gives a good aesthetic view to the

building because of its unique geometry. In this paper a 24 storey building is considered using outrigger and diagrid

system, and it is analyzed by response spectrum analysis, that is a linear dynamic analysis by the use of ETABS

software. The objective of this paper is to do response spectrum analysis and compare performance of 6 different

models with same height but different structure geometry. To find out the effect of different outrigger and diagrid on

seismic performance of the structure.

KEYWORDS: Outrigger, Diagrid, Lateral load resisting system, High-rise building & Response spectrum analysis

Received: May 25, 2020; Accepted: Jun 27, 2020; Published: Aug 07, 2020; Paper Id.: IJMPERDJUN2020686

1. INTRODUCTION

Construction of high-rise building is a big asset for human life as well as wild life, as it can be observed that

deforestation is going on around the world and destroying the habitats of wild life and more importantly the main

source of oxygen on earth (forests). But as the height of structures increases design of the structure will be a big

challenge for engineers because of lateral loads that act drastically on the building, to tackle this challenges there

are number of structural system to resist lateral loads without adding to plan dimension or tonnage of the building.

Outrigger is one of these systems that is commonly used as lateral load resisting system in high-rise and super

high-rise buildings. Another system that is newly developed mechanism for resisting lateral load is diagrid

system. These two systems were modeled and analyzed by ETABS software to compare their performance.

2. LATERAL LOAD RESISTING SYSTEMS

Before structure members were considered to carry only gravity loads, but after advancement in structural system

lateral loads (wind and earthquake) was also taken into account especially in high-rise buildings, as slenderness

and flexibility increases the building will be affected mostly by lateral loads. There no of lateral load resisting

Orig

ina

l Article

International Journal of Mechanical and Production

Engineering Research and Development (IJMPERD)

ISSN (P): 2249–6890; ISSN (E): 2249–8001

Vol. 10, Issue 3, Jun 2020, 7257-7266

© TJPR Pvt. Ltd.

7258 Mustafa Hussaini & Sandeep Nasier

Impact Factor (JCC): 8.8746 SCOPUS Indexed Journal NAAS Rating: 3.11

system that are highly effective against lateral load and a stable building can be designed with. It is important to

find an adequate system depending on height of the structure. Following are some of lateral load resisting

systems:

Rigid frame system

Braced frame system

Shear wall system

Disgrid system

Outrigger system

Tube system

Bundled tube system

3. OUTRIGGER SYSTEM

In order to effectively control the excessive lateral deflection due to lateral loads outrigger system can be used as

lateral load resisting structural system. This system can be used in high seismic zone and wind load dominant.

This system comprises a centrally located core shear wall, belt truss and outriggers that connects the core shear

wall with outer columns so that structure can act as a unit against lateral loads. The configuration of bracing

system can be different in outriggers. The further rotation of outriggers can be resist by outer columns (columns at

the periphery) of the structure. The induced tension and compression forces on these columns can create moment

resisting to the horizontal loading. Analysis of will complicated with braced frame and outriggers because

outriggers will be forced to deflect with braced frame that will be subjected to bending and racking shear

deformation. The same assumption that neglect shear deformation in concrete “plane section remain plane” does

not stand for braced frame. Concrete walls will be assumed as simple wide column and its behavior will be

applied on it but this will not work for trusses.

Figure 1: Behavior of Frames with Outrigger

Seismic Performance of High-Rise Building using Outrigger and Diagrid Structural System 7259


3. DIAGRID SYSTEM

Diagrid is a specific form of space truss. The diagonal are provide at the perimeter of the structure made up of

series of triangulated truss system. There are number of famous structures that are built by diagrid structural

system around the world; Swiss Re in London, Hearst Tower in New York, Capital Gate Tower in Abu Dhabi etc.

(a) (b) (c)

Figure 2: a) Swiss Tower in London b) Hearst Tower in New York c) Capital Gate Tower in Abu Dhabi

Diagrid system has a good aesthetic view and easily recognized. It provide a clear view to the outside the

building and less obstruction. Diagrid structural system provides significant flexibility with floor plan because it

avoids interior and corner columns. Diagrid structural system saves almost 20% of structural steel weight as

compare conventional rigid frame structure. The diagonal members of diagrid structural system can carry both

gravity as well as lateral loads due to its triangulated configuration. Diagrid system minimize shear deformation as

diagonal members carry lateral shear by axial action.

4. MODELING AND ANALYSIS OF 24 STOREY BUILDING

4.1 Modeling of 24 Storey Building

The 24 storey building has (40x40)m plan dimension. The height of each storey is 3.5m. the angle of inclination is

kept the same through the height for diagrid structure. The inclined columns for diagrid structure is provided at

10m spacing. The design dead load and live loads are shown in the table 1. Seismic parameters are given as below

in table 2. Modeling and analysis of all models are carried out using ETABS software. For linear static and linear

dynamic analysis the beams and columns are modeled by beam element, and braces are modeled by truss element.

Table 1: Loading Parameter

S. No Live load in KN/m2 Imposed dead load in KN/m2

1 3 1

Table 2: Seismic parameter

S. No Importance

factor I

Zone Factor

Z

Response Reduction

Factor R

Type of Soil Damping Ratio

1 1 0.24 5 II 5%



Table 3: Diagrid parameters

S. No Column size in

mm

Beam size in

mm

Bracing size in

mm

Slab thickness in

mm

Angle

Degree

1 700x700 450x450 450x450 200 54

Table 4: Outrigger Parameter

S. No Column size in

mm Beam size in mm

Bracing size in

mm

Core shear wall & slab

thickness in mm

1 700x700 450x450 450x450 200

(a) (b)

Figure 1: (a) Diagrid with an angle of 54o (b) Diagrid in Diagrid with angle of 54o

(a) (b)



Figure 2: (a) Diagrid in diagrid (b) Outrigger with X-bracing

(a) (b)

Figure 3: (a) Outrigger with K-bracing (b) Outrigger with E-bracing

4.2 Analysis Results of 24 Storey Building

The analysis result will be shown in terms of time period, base share, dispalcement and overturning moment. The

time period of the models will be shown in table 4 and fig 4. Base share of the building will be shown in table 5

and fig 5. Displacement will be displayed in table 6 and fig 6, and overturning moment will be shown in table 7

and fig 7.

Table 4: Time period



Figure 4: Time period in sec

Table 5: Base shear in KN

Figure 5: Base shear in KN

Table 6: Displacement in mm



Figure 6: Displacement in mm

Table 7: Overturning Moment



Figure 7: Overturning Moment

5. CONCLUSIONS

In this paper modeling and analysis of 24 storey building with outrigger and diagrid system is presented in details.

A regular floor paln of 40x40 m has been considered for modeling and analysis purpose. All seismic parameters

were drawn from IS 1893:2016 considering all load combinations.

In diagrid system it was observed that all lateral loads are resisted by diagonal memnbers and gravity

loads were resisted by both diagonal members and vertical members as well.

Because of increase in lever arm of diagonal members, this system is very effective in resisting lateral

load.

Outrigger system is also very effective in resisting lateral loads as it can be observed in the results we

obtained but it make disturbance in planning interior and façade of the building. In this paper an attempt has been

made to reduce this disturbance by providing K and E bracing instead of X-bracing, that the result were satisfying

without lose of strenght and stiffness.

But diagrid system provide much more flexibility in terms of planning interior and façade of the

building.

REFRENCES

1. Akshat, & Singh, G. (2018). Dynamic analysis of diagrid structural system in high rise steel buildings. International

Journal of Civil Engineering and Technology, 9(8), 71–79.

2. Chavan, A. V, & Shelar, P. V. V. (2017). Pushover Analysis of High Rise Building and Outrigger System With or

Without In-Filled Walls. International Research Journal of Engineering and Technology(IRJET), 4(7), 1439–1445.

3. Etemad, A. H., & Kumar Tiwary, A. (2019). Article ID: IJCIET_10_03_196 Cite this Article: Abdul Halim Etemad

and Aditya Kumar Tiwary, Comparison of Tubular, Outrigger and Bracing System for Stabilization of High-Rise

Buildings. International Journal of Civil Engineering and Technology (IJCIET), 10(03), 1968–1977.

4. Jani, K., & Patel, P. V. (2013). Analysis and design of diagrid structural system for high rise steel buildings.

Procedia Engineering, 51, 92–100. https://doi.org/10.1016/j.proeng.2013.01.015

5. Kala, A., Mangulkar, M., & Jain, I. (2017). The use of outrigger and belt truss system for high-rise RCC building.



International Journal of Civil Engineering and Technology, 8(7), 1125–1129.

6. Kumar, R., & Sharma, P. (2019). Comparative Study of Diagrid Structure System in High Rise Buildings With

Braced Frame Structure. International Journal of Civil Engineering and Technology (IJCIET), 10(3), 1826–1831.

7. Naik, S. R., Desai, S. N., & Naik, M. P. (2018). Article ID: IJCIET_09_13_154 Ratio Considering Seismic Non-

Linear Time History Analysis. International Journal of Civil Engineering and Technology (IJCIET), 9(13), 1532–

1539.

http://www.iaeme.com/IJCIET/index.asp1532http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=9&IT

ype=13http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=9&IType=13http://www.iaeme.com/IJCI

ET/index.asp1533

8. Sapkota, B., Surumi, R. S., & Jeyashree, T. M. (2017). Comparative study on seismic performance of high-rise

building with energy dissipation and outrigger belt truss system. International Journal of Civil Engineering and

Technology, 8(4), 1539–1545.

9. Shadhan, K. K. (2015). Optimal Diagrid Angle To Minimize Drift in High-Rise Steel Buildings. 6(11), 1–10.

10. Sharma, P., & Singh, G. (2018). Dynamic analysis of outrigger systems in high rise building against lateral loading.

International Journal of Civil Engineering and Technology, 9(8), 61–70.

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