ACCESSSTEEL_Scheme development Primary beams for multi storey buildings for commercial and residential use.pdf

8/13/2019 ACCESSSTEEL_Scheme development Primary beams for multi storey buildings for commercial and residential use.pdf

1/7

Scheme Development: Primary beams for multi-storey buildings for commercial andresidential use

SS014a-EN-EU

Scheme Development: Primary beams for mult i-storeybuildings for commercial and residential use

Outlines the different types of primary beams used for multi-storey buildings. Summarisestheir benefits, describes the key issues for design and presents information for initial

design.

Contents

1. Form of Construction 2

2. Application Benefits 3

3. Design Aspects 3

Page 1

Scheme Development: Primary beams for multi-storey buildings for commercial and residential use

CreatedonFriday,

June

23,

2006

Thismaterialiscopyright-allrightsreserved.

Useofthisdocumentissu

bjecttothetermsandconditionsoftheAccessSteelLicenceAgreement


2/7


SS014a-EN-EU

1. Form of Construction

Primary beams support secondary beams, and by their loading, tend to be heavier or deeperthan secondary beams of the same span. They are subject to one or more point loads at a

spacing given by the span of the floor slab. Primary beams can be of two generic forms:

Hot rolled steel sections (using IPE or UB sections)

Fabricated sections (from welded plates)

For long spanning primary beams (span > 12 m), illustrated in Figure 1.1, it is possible to

form large rectangular openings in the webs of the sections close to mid-span where the shear

forces are low. Fabricated beams are often used as primary beams because they can be

designed efficiently as composite asymmetric sections. Cellular beams can also be used as

primary beams, although they are less efficient for this case because of the higher shear forces

acting on primary beams. Primary beams should generally connect to the flanges of columnsfor stiffness and fabrication efficiency of the connections.

6 - 9 m

12 - 18 m

Figure 1.1 Layout of long span primary beams of 12 to 18 m span

Page 2


CreatedonFriday,

June

23,

2006





3/7


SS014a-EN-EU

Table 3.1

2. Application Benefits

The benefits of long span primary beams are as follows: Primary beams can be designed for a

range of spans either hot rolled or fabricated beams

may be used

Fabricated sections are efficient they are tailor-made for their spanand load

Service integration large web openings can be formedclose to mid-span

Saving on fire protection costs heavier sections can achieve up to 30minutes fire resistance without

protection

3. Design Aspects

The structural design of primary beams depends on the size and layout of beams in the floor

grillage. Table 3.1and Table 3.2give typical sizes of primary beams for various column

spacings in orthogonal directions.

Sizes of composite primary beams using IPE sections

Maximum span of primary beam (m)Span of secondary beams

(m) 6 7,5 9 10,5 12

6 IPE 360 IPE 400 IPE 450 IPE 550 IPE 600R

7,5 IPE 400 IPE 450 IPE 550 IPE 600R IPE 750x137

9 IPE 450 IPE 500 IPE 600 IPE 750x137 IPE 750x173

Imposed load = 3 kN/m2

plus 1 kN/m2

for partitions etc

Table 3.2 Sizes of composite primary beams using UB sectionsMaximum span of primary beam (m)

Span of secondary beams(m) 6 7,5 9 10,5 12

6305 127

42 kg/m356 171

57 kg/m406 178

74 kg/m457 191

98 kg/m533 210

122 kg/m

7,5356 171

45 kg/m406 178

67 kg/m457 191

89 kg/m533 210

122 kg/m610 229

140 kg/m

9406 178

54 kg/m

457 191

74 kg/m

533 210

101 kg/m

610 229

140 kg/m

610 305

179 kg/mImposed load = 3 kN/m

2plus 1 kN/m

2for partitions etc

Page 3


CreatedonFriday,

June

23,

2006





4/7

Primary beams should be connected to column flanges, for example by end plate details of the

form of


SS014a-EN-EU

Figure 1.1. Extended end plates increase the stiffness of the connection and reduce

deflections of the beam.

70

70

50 50

4050

10

120

90

70

70

A - A

B - B

A

A

B

B

Figure 3.1 End plate connection of primary beam to column and fin plate connection ofsecondary beam to column

Secondary beams may be connected to primary beams by end plate details but the top flange

should be notched where beams are of the same level, as shown in Figure 3.2. Fin plate or

double angle cleats may alternatively be used.

90

120

50

40

90

A - A

A

A

Figure 3.2 Beam-beam connection showing notch at top flangePage 4


CreatedonFriday,

June

23,

2006





5/7


SS014a-EN-EU

For fabricated beams, a variety of section sizes is possible. For efficient structural design, the

span/depth ratio of composite primary beams is in the range of 15-18. However, the depth of

the section can be increased in order to achieve the maximum size of web opening for service

integration (typically up to 70% of the depth of the section). An example of a fabricated

primary beam is shown in Figure 3.3.

Figure 3.3 Long span fabricated beam with a variety of opening shapes

Page 5


CreatedonFriday,

June

23,

2006





6/7


SS014a-EN-EU

Quality Record

RESOURCE TITLE Scheme Development: Primary beams for multi-storey buildings forcommercial and residential use

Reference(s)

ORIGINAL DOCUMENT

Name Company Date

Created by R.M. Lawson SCI Jan 05

Technical content checked by G.W. Owens SCI May 05

Editorial content checked by D.C. Iles SCI May 05

Technical content endorsed by thefollowing STEEL Partners:

1. UK G.W. Owens SCI 26/5/05

2. France A. Bureau CTICM 26/5/05

3. Sweden A. Olsson SBI 26/5/05

4. Germany C. Mueller RWTH 11/5/05

5. Spain J. Chica Labein 20/5/05

6. Luxembourg M. Haller PARE 26/5/05

Resource approved by TechnicalCoordinator

G.W. Owens SCI 26/4/06

TRANSLATED DOCUMENT

This Translation made and checked by

Translated resource approved by

Page 6


CreatedonFriday,

June

23,

2006





7/7


SS014a-EN-EU

Wrapper Information

Title* Scheme Development: Primary beams for multi-storey buildings for commercial andresidential use

Series

Description* Outlines the different types of primary beams used for multi-storey buildings. Summarisestheir benefits, describes the key issues for design and presents information for initial design.

Access Level* Expertise Practitioner

Identifiers* Filename P:\CMP\CMP554\Finalization\SS files\014\SS014a-EN-EU.doc

Format Microsoft Office Word; 7 Pages; 214kb;

Resource Type Scheme DevelopmentCategory*

Viewpoint Architect, Engineer

Subject* Application Area(s) Multi-storey Buildings;

Created Date 27/05/2005Dates

Last Modified Date

Checked Date

Valid From

Valid To

27/05/2005

15/05/2005

01/06/2005

Language(s)* English

Author

Checked By

Mark Lawson, Steel Construction Institute

Graham Owens, Steel Construction Institute

Contacts

Approved by

Editor

Last Modified By

Graham Owens. Steel Construction Institute

David Iles, Steel Construction Institute

Graham Owens, Steel Construction Institute

Keywords* Commercial buildings, Architectural Design, Conceptual Design, Initial Design, I Sectionsand H Sections, Beams with Web openings

See Also Eurocode Reference

Worked Example(s)

Commentary

Discussion

Other

Coverage National Applicability Europe

SpecialInstructions

Page 7


CreatedonFriday,

June

23,

2006




Documents

ACCESSSTEEL_Scheme development Primary beams for multi storey buildings for commercial and residential use.pdf