# Wind Analysis of a Industrial Steel Structure with Varying Connections in the Member

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#### Wind Analysis of a Industrial Steel Structure with Varying Connections in the Member

Prof. Sagar L.Belgaonkar1

Assistant Professor Department of Civil Engineering

1. G. Balekundri Institute of Technology Belgaum, India

Prof. Madhuri N Kesarkar2 Assistant Professor Department of Civil Engineering

Miss. Manisha Balaram Kakatkar3 Post Graduate Student

Department of Civil Engineering

S. G. Balekundri Institute of Technology Belgaum, India

Abstract In this report, type of structure and most feasible type of connection, different types of connections, compare the node displacements and to suggest a suitable type of connection are studied. Analysis is carried out by using STAAD Pro. to see the range of parameters such as node displacement, beam relative displacement, beam end forces, weight and beam forces such as maximum axial forces, bending moments and shear forces of the structure.

KeywordsBolted; welded; shear and moment connections; wind load; maximum node displacement; bending moment; shear force; weight and axial force.

1. INTRODUCTION

Connections are the glue that holds a steel structure together. Connections facilitate flow of moments and different types of forces in members and also allow transfer of forces up to foundation level. The ultimate moto or goals of connection design is to have a economical, safe and not so complex design, so that without any difficulty it can be produced and assembled at site. Connection depends on type of loading, strength, stiffness, economy and difficulty or ease of erection. Connecting materials such as angles, plates etc. are fixed to one member at workshop and other member in the field.

1. Objectives

• To study the range of moments and general connection details.

• To study the type of structure and most feasible type of connection.

• To study different types of connections.

• To compare the node displacements and to suggest a suitable type of connection.

2. CONNECTIONS

1. Bolted connections

• Nuts

Types of nuts

1. Standard : height is approx. 0.8 d

2. High : height is 1.2 to 2 d

3. Low : height is 0.4 d Where, d = diameter of bolt

• Washers

Types of washers

1. Standard washers

2. Standard but hardened for slip-resistant connections

3. Wedge washers for connection to flange of I-sections.

• Bolts

Type of bolts

1. Black bolts

2. Turned bolts

3. Ribbed bolts

4. High-Strength bolts

2. Welded Connections

Types of welds

• Fillet weld

• Groove weld

• Slot and plug weld

3. Shear connections

A connection is required to transfer a force only and there may not be any moment acting on the group of connectors, even though the connection may be capable of transmitting some amount of moment. Such a connection is referred as a shear, simple, pinned, force connection.

Types of simple connections

• Lap and butt joints

• Truss joint connections

• Connections at beam column junctions

1. Web angle connection

2. Seat angle connection

3. Stiffened seat angle connection

4. Header plate connections

• Tension and flange splices

4. Moment Resistant Connections

A connection which is capable of transferring moment, axial force and shear from one member to another is referred as moment resistant connection.

Types of Moment Resistant connections

• Eccentrically loaded connections

• T-stub connections

• Flange angle connections

Table 2: Description of the types of models

 Sl. no Numbers of models Model 1 Model 2 Model 3 Model 4 Model 5 1 Plan size 12m x 12m 12m x 12m 40m x 40m 40m x 40m 40m x 40m 2 Bay size 6m 6m 20m 20m 20m 3 Height 3.2m 3.2m 3.2m 3.5m 3.7m 4 Column size ISWB 600 ISWB 600 ISWB 600 ISWB 600 ISWB 600 5 Beam size ISHB 450 ISHB 450 ISHB 450 ISHB 450 ISHB 450 6 Central beam size – UB610x229x1 39.9 UB610x 229×139.9 UB610 x229 x139.9 UB610x 229×139.9 7 Rectangular concrete plinth beam size 250mmx 600mm 250mm x 600mm 250mm x 600mm 250mm x600m m 250mx600m m

3. Methodology

1. General

The present work is carried to study the difference between structural connections and behavior of structure with different types of structural connections. The software used for the analysis is STAAD Pro V8i. A plan of three storey steel structure building is considered as a model, analysis is done using STAAD Pro V8i. and the design of structural joints is carried manually using excel sheets.

Following studies are carried:

• Difference between bolted and welded connections

• Behavior of structure with different structural connections at different location of structure.

• Different types of structural connections will be checked for wind speed

• The range of moments and general connection details are studied.

• The most feasible type of connection for the type of structure is studied

2. STAAD Pro V8i

STAAD Pro V8i is a full featured program that can be used for the simplest programs or the most complex projects. This software gives better result of steel structures.

3. Modeling And Analysis

• Procedure followed to generate the models

Fifteen different types of framed steel structure of three story industrial building are modeled. Following parameters are considered

Table 1: Physical Properties

Figure 1: Modeling in Staad ProV8i

 Sl.no Material Steel Concrete 1 Yield strength 250 N/mm2. – 2 Modulus of elasticity 2×105 N/mm2 25×103 N/mm2 3 Density 7850 kg/m3 25 kN/m2 4 Grade 250 N/mm2 M25 5 Poissons ratio 0.3 0.2

Figure 4: Model 3 with bay size 40 m X40 m

Figure 2: Model 1 with bay size 12 m X12 m

Fgure 3: Model 2 with bay size 12 m X12 m

Figure 5: Model 4 with bay size 40 m X40 m

Figure 6: Model 5 with bay size 40 m X40 m

Table 3: Calculated Wind Forces

 Sl. No Story no. Height in m FkN/m2 Amount of wind force acting permeter on member in kN/m 1 1st and 2nd floor 3.7 1.5 5.55 2 3rd floor 1.85 1.5 2.775 3 1st and 2nd Floor 3.5 1.5 5.25 4 3rd floor 1.75 1.5 2.625
4. CALCULATION OF FORCES

1. Calculation of wind load

According to IS 875 (Part III) 1987.

• Design wind speed, Vz = Vb x k1 x k2 x k3

Vb = 33 m/s k1 = 1.0

k2 = 1.10

k3 = 1.0

Vz = 33 x 1.0 x 1.10 x 1.0

Vz = 36.3 m/s

• Wind pressure, pz = 0.6 x Vz2

pz = 0..6 x 36.32

pz = 790.614 N/m2

• Design wind pressure, pd = kd x ka x kc x pz

pd = 0.9 x 0.9 x 1 x 790.614 pd = 640.397 N

• Wind load on individual members, F = (Cpe Cpi) A x pd

F = (0.7 (-0.2)) A x 640.397

F = 576.35 A N F = 0.576 kN/m2

As calculated wind loads are nominal a minimum wind load of

1.5 kN/m2 is considered for analysis.

Table 4: Results for Displacements ant relative Displacement

 Plan size in m Height in m Self-weight in kN Displacement in mm Relative Displacement inmm 12 x 12 3.2 4146.83 3.368 1.025 12 x 12 3.2 4082.39 40.76 1.84 40 x 40 3.2 41521.33 37.884 126.567 40 x 40 3.5 41531.93 41.426 551.469 40 x 40 3.7 41538.99 43.786 551.469 12 x 12 3.2 4142.45 63.128 4.275 12 x 12 3.2 4146.83 3.423 1.025 40 x 40 3.2 41521.33 37.945 126.567 40 x 40 3.5 41531.93 41.499 551.47 40 x 40 3.7 41538.99 43.868 551.47 12 x 12 3.2 4142.45 26.842 3.711 12 x 12 3.2 4146.83 3.328 1.025 40 x 40 3.2 41521.33 37.917 126.567 40 x 40 3.5 41531.93 41.462 551.14 40 x 40 3.7 41538.99 43.824 551.14

Table 5: Results for Bending Moment and Shear Forces

 Plan size in m Height in m Beam Force in kN Bending moment in kNm Shear force in kN 12 x 12 3.2 1888.31 16.54 15.90 12 x 12 3.2 1492.79 387.91 198.68 40 x 40 3.2 21126.15 176.71 53.01 40 x 40 3.5 21122.07 176.71 53.01 40 x 40 3.7 21119.4 176.71 53.01 12 x 12 3.2 1540.83 221.90 69.34 12 x 12 3.2 1914.55 15.90 15.90 40 x 40 3.2 21155.24 176.71 53.01 40 x 40 3.5 21153.42 176.71 53.01 40 x 40 3.7 21152.23 176.71 53.01 12 x 12 3.2 1587.43 455.02 284.04 12 x 12 3.2 1868.04 30.65 17.88 40 x 40 3.2 21142.17 176.71 `68.92 40 x 40 3.5 21137.71 176.71 66.43 40 x 40 3.7 21134.79 176.71 64.92
5. RESULT AND DISCUSSIONS

After the analysis significant change in parameters such as node displacement, beam relative displacement, beam end forces, weight and beam forces such as maximum axial forces, bending moments and shear forces of the structure are noticed.

6. DISCUSSION AND CONCLUSION.

1. In the first model the connections are fixed. Hence the node displacements observed in this model are minimum.

2. In the sixth model, the joints are hinged (releases are provided). Here maximum displacements are observed.

3. In the eleventh model, only the joints where the columns overlap or have a joint are hinged. It is observed that the values of node displacement range between the first and sixth model. All the three models have the same geometry and member sizes.

4. These trials were taken for different models, different member sizes, different length and span sizes. However the results are similar to first trial.

5. From the above results, we can conclude that the fixed connections are best suited as the node displacements are minimum and are less than H/250 mm. which is the minimum requirement for a structure to be safe under displacements.

REFERENCES

1. Tsioupanis Kyriakos, January 2012, Moment Capacity of Simple Steel Connections, Department of Civil Engineering, Frederick University.

2. Charleys W. Dolan et al., March April 1987, Moment Resistant Connections and Simple Connections, Specially Founded R & D Program, PCI Journal.

3. Erik Anders Nelson, 2011, Simple Shear Connections-Not So Simple, Structures Congress, ASCE.

4. Jaswant N. Arlekar and C. V. R. Murty, August 2004, Shear Moment Interaction for Design of Steel Beam to Column Connections, 13th World Conference on Earthquake Engineering Vancouver, B. C., Canada, Paper No. 635.

5. IS: 875 (Part 1) 1987, Indian Standard, Code of Practice for Design Loads (Other than Earthquake) for Buildings and Structures, For Dead Loads.

6. IS: 875 (Part 2) 1987, Indian Standard, Code of Practice for Design Loads (Other than Earthquake) for Buildings and Structures, For Imposed Loads.

7. IS: 875 (Part 3) 1987, Indian Standard, Code of Practice for Design Loads (Other than Earthquake) for Buildings and Structures, For Wind Loads.