Study on Diagrid Structural System Used in High Rise Building by Using Etabs

doi:10.21203/rs.3.rs-2088228/v1

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Study on Diagrid Structural System Used in High Rise Building by Using Etabs

https://doi.org/10.21203/rs.3.rs-2088228/v1

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Now a days. The reinforcement concretes frames are mostly used in the world. With increasing population, the land is scarce and expensive, where the high-rise building is representing the best solution for the solving the problem. The evolution of the tall buildings structural systems based on the new concepts with newly adopted high strength materials and construction methods have to developed the stiffness and lightness. recently diagrid system is adopted in the high rise building to improve efficiency and flexibility in architectural planning. In this study, the 4 models are prepared for the 12-storey building by providing open space core section in the structure is prepared with 4 different angles i.e., 50.2 ⁰ (2-storey connection), 67.4⁰ (4-storey connection module), 74.2 ⁰(6- storey connection module), 82⁰ (12 storey connection) from that finding optimum angle for the 12-storey model in all criteria. After the 12-storey building analysis, compare the results with the optimum angle for the 12-storey building and simple frame building in terms of storey displacement, storey drifts and materials consumption for different model and also apply the optimum angle for the 24-storey building of diagrid system compared with the 24-storey simple frame structure in terms of all criteria.

Diagrid system

optimum angle

stiffness

flexibility

storey displacement

storey drifts and materials consumption

Tal buildings appeared in the late 19th century in the United States. They are what are known as “American building styles”, meaning the most important tall buildings built in the United States. Today, they are a worldwide architectural phenomenon. Many high-rise buildings are being built around the world especially in Asian countries like China, Korea, Japan and Malaysia. According to available and published data in the 1980s, about 49%of the world’s tall buildings are located in north America.

The distribution of tall buildings has changed significantly, with Asia now accounting for the share ate 32% and north America 24% The development of high-rise buildings involves various complex factors such as economies, aesthetics, technology, city regulations and politics. of these, the economy is the main determining factor. For a very tall building, its structural design is often governed by its lateral stiffness. Compared to traditional tall rectangular structures such as framed tubes, diagrid structures carry lateral wind loads much more efficiently due to the axial action of the diagonal members. Today’s architects have lost interest in the aesthetics created by traditional framed tubes consisting of orthogonal and large diagonal elements. Because they are always looking for something new and different. Diagrid system construction offers excellent structural efficiency without the structural loading of vertical columns and also opens up new aesthetics looks for high rise building.

The diagrid looks nice and is easy to find. The structural efficiency of the diagrid system helps reduce Interior and corner pillars, greatly increasing floor plan flexibility. The diagrid system saves about 20% of the weight of structural steel conventional construction. The diagonal bars of the diagrid structural system carry dead loads and lateral forces due to the triangular frame structure. Diagrid can save up to 20–30% on structural steel in high rise buildings. The term diagrid is a combination of the words diagonal and refers toa structure that is essentially of unitary thickness and uses triangulation to obtain structural integrity. Refers to the system. The structure of the diagrid system can be planar, crystalline, or adopt multiple curvatures, crystal shape or curvature is often used to increase stiffness diagonal side carry the lateral and gravity loads of the building and serve to support the floor edges.

There are engineering reasons to recommend using a diagrid of the following:

1. Increased structural stability through triangulation.

2. A combination of dead load, pay load and side load in a storage system can improve efficiency.

3. Provides an alternate load path in the event of structural failure.

4. Lightening of the superstructure may be proportional to the reduction of stresses on the foundation.

In this study from chapter, we study behavior of diagrid system used in tall building by using ETABS and the following objectives are:

To find the optimum angle for the 12-storey diagrid system for the high-rise building by using different angles
To analyse the comparative results of the 12-storey optimum angle diagrid system with 12 storey simple frame structure.
To analyse the 24-storey optimum angle of diagrid system of high-rise building.
To analyse the comparative results of the 24-storey optimum angle diagrid system with 24 storey simple frame structure.

In this study, the 3 models are prepared. From those models, the 12-storey model is prepared by 4 different uniform angles i.e., 50.20⁰, 67.4⁰, 74.2⁰, 82⁰ by doing analysis, find the optimum angle for the 12-storey model in all criteria and observe the results of reactions, storey displacement, storey drifts, materials consumption etc. For the 4 different angles for given 12 storey building. After the 12-storey building analysis, find the optimum angle for the 12-storey building and compare results with the 12-storey simple frame building and also apply the optimum angle for the 24-storey building of diagrid system compared with the 24-storey simple frame structure in terms of all criteria. Three models are prepared

1. 12 storeys with 4 different angles

2. 12 storey optimum angle and compared with 12 storey conventional building

3. 24 storey optimum angle and compared with 24 storey conventional building

Geometrical data

In this study, the construction shape of the structural model was considered, and the following data were used for modeling for all models.

Structural configuration

Table 2.1

Structural configuration
Parameter	Configuration
Structure type	Concrete structure
Plan dimension	36 x36 m
Height of storey	3.6 m
Slab thickness	120 mm
Grade of steel	40 N /mm²
Yield strength of steel	15 N/ mm²

Seismic specifications

Zone: II
Zone factor: 0.16
Response reduction factor :5
Type of soil: II (medium soil)

Loading specifications

Dead load
Live load
Floor load :1.2 KN/mm²
Top storey load :2.1 KN/mm²

Model:1

12 storey model with 4 different angles

Table 3.1

Sizes of 12 storey with different angles models
			Model-A
Member	No	A-1mm	A-2 mm	A-3 mm	A-4 mm
Beam	B1	300x600	300x600	300x600	300x600
	B2	300x600	300x600	300x600	300x600
	B3	300x600	300x600	300x600	300x600
Column	C1	700x700	700 x 700	700x700	700x700
Diagrid	D	500x500	500x500	450x450	500x500

Model: 2

12 storey optimum angle diagrid system and 12 storey conventional building

Table 3.2

Sizes of members for 12 storey buildings
	Member No’s	Diagrid system of 67.4⁰ angle in mm	Simple frame structure in mm
	B1	300x450	300 x 450
Beam	B2	300x400	300 x 450
	B3	300x400	300x400
Column	C1	500 x 500	750 x 750
Diagrid	D1	300x300	450x450

Model: 3

24 storey optimum angle diagrid system and 24 storey conventional building

Table 3.3

sizes of members for the 24-storey building
Member	Member No’s.	Diagrid Structure of 67.4⁰ angle in mm	Simple Frame Structure in mm
	B1	300 x500	300 x 500
Beam	B2	300x500	300 x 500
	B3	300x450	300x450
Column	C1	700 x 700	750 x 750
Diagrid	D1	300x300	450x 450

4.1 Model 1

1. Displacement Results: As we considered the four corners of the diagrid system for a 12-storey building, we can get the result as shown in the below Fig. 4.1 has a smaller offset for the loft angle of 50.2⁰ for the A-1 model for a 12-storey building. But from the results of A-2, A-3, the displacement results are lower for the angles of 67.4⁰ and 74.5⁰ than for the others. Therefore, the optimal for diagrid building in the region of 65⁰ to 75⁰

2. Storey Drifts Results: According to the phase deviation results shown in Fig. 4.2, models A-2 and A-3 are better, which clearly shows that the angular region from 65⁰ to 75⁰

3. Storey Shear Results: Storey shear results clearly shown in Fig. 4.3 that models A-2 and A-3 give better results, clearly indicating that the angle range of 65⁰ to 75⁰ is optimal storey height for 12 storey building.

4. Materials Consumption: This observation also directly affects the amount of the building. Therefore, from the Fig. 4.4 the optimum angle in between 65⁰ to 75⁰.From the above results it can be seen that consumption in following regions between 65⁰ to 75⁰ of the optimal angles, but as the number of floor increases, minimal concrete consumption is observed. This also directly affects the cost of the building. Therefore, the optimal angle is in between 65⁰ and 75⁰

4.2 Model 2

Comparison between 12 Storey Diagrid System with 12 storey Conventional Building

1. Displacement Results

Table 4.1

The displacements for the 12-storey diagrid system and simple frame system
	Case	Diagrid system	Simple frame structure	Permissible values
Top storey displacement	WLX/WLY	45.6 mm	78.3mm	86.4mm

2. Storey Drifts Results

Table 4.2

The storey drifts for the 12-storey Diagrid system and conventional building
	Case	Diagrid system	Simple frame structure	Permissible values
Storey Drifts	EQX/EQY	1.098 mm	1.2 mm	14.4mm

3. Storey Shear Result

4. Material Consumption

5. Reaction forces Results

Table 4.2

Reaction Forces
Loading (KN)	Reaction force in diagrid system (KN)	Reaction force in simple frame(KN)
downward loads (DL + LL)	50486.412	57862.235
Earthquake load in X- direction	543.078	598.095
Earthquake load in Y- direction	543.078	598.095
Wind load in X- direction	1386.06	1386.066
Wind load in Y- direction	1386.06	1386.066

4.3: Model 3

Analysis of 24 storey diagrid system and 24 storey simple conventional building

1. Displacement Results

Table 4.3

The displacement for the 24-storey diagrid structure and conventional frame structure
	Case	Diagrid system	Simple frame structure	Permissible values
Top storey displacement	WLX/WLY	152.5 mm	154mm	172.8mm

2. Storey Drift Results

Table 4.4

The storey drifts values for the 24-storey Diagrid system and traditional frame building
	Case		Diagrid system		Conventional building	Permissible values
Storey Drifts		EQX/EQY		1.0878 mm	1.32 mm	14.4mm

3. Storey Shear Results

4. Materials Consumption

Concrete quantity and steel consumption are calculated for two structures. It can be seen that the material consumption of simple frame buildings is higher that the of diagonal structures as shown in the figure above, the difference in concrete consumption for buildings is 13 .01% and steel is 57.9%.

It emerges from this study, considering different angles of the diagonal grid and different floors of the building. Four different diagonal lines are recorded on the 36 x 36 m floor plan. Here we present a comparative analysis of diagrid structural systems and simple frame buildings of 50.2, 67.4, 74.5, 82.1 for 12 and 24 storeys. Model and analysis the structure using ETABS 9.7.4 software. Analysis results of top floor reaction force displacement, floor movement, floor shear and materials consumption are posted. In addition, designs for both structure IDs are performed and optimal element sizes are selected to meet code standard.

From this study, we conclude

Finally, the optimum angle for the diagrid system for the any storey in region of 65⁰ to 75⁰.
More stiffness and less storey displacement in angle of 65⁰ to 75⁰ for the diagrid structures.
It gives the best results in terms of top layer displacement, storey drift, floor shear and material consumption in the optimal storey area as the number of stories increases.
The consumption of materials for the conventional building is higher than the diagrid system in the value of 13.01% in concrete and 20% in steel.
In the diagrid system, the lateral resistance is more when compared to the conventional building when the stories are increased.
Basically, the sizes of the both structures are assumed to the same but failures to be occurred in the top storey in the simple frame structure. So that the selected higher sizes in the simple frame structure.
The storey displacement is less in the diagrid structure because of the lateral loads are resisted by the diagrids in the structure.

So, from the results we understand that the compared to conventional building, the diagrid system gives the better lateral resistance in zone II

“The authors declare that no funds, grants or other support were received during the preparation of this manuscript.”

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No competing interests reported.

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Study on Diagrid Structural System Used in High Rise Building by Using Etabs

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Abstract

Figures

1. Introduction

2. Design Concept

3. Modelling

4. Results And Discussion

4.1 Model 1

4.2 Model 2

5. Conclusions

Declarations

References

Additional Declarations

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