Scheme Development Vertical Structure for Multi-Story Blgds

8/3/2019 Scheme Development Vertical Structure for Multi-Story Blgds

1/8

Scheme Development: Vertical structure for multi-storey buildings for commercial

and residential use

SS016a-EN-EU

Scheme Development: Vertical structure for multi-storeybuildings for commercial and residential use

Outlines the types of columns and vertical bracing members used in multi-storey buildingsand presents information for their initial design.

Contents

1. Form of Construction 2

2. H Sections 3

3. Partially Encased H Sections 4

4. Concrete Filled Structural Hollow Sections 4

5. Fire Engineering of Columns 5

6. Column Splices 6

7. Vertical Bracing 7

Page 1

Scheme Development: Vertical structure for multi-storey buildings for commercial and residential use

CreatedonFriday,

March18,

2011

Thismaterialiscopyright-allrightsreserved.

Useofthisdocumentissu

bjecttothetermsandconditionsoftheAccessSteelLicenceAgreement


2/8


and residential use

SS016a-EN-EU

1. Form of Construction

The columns and other vertical load-bearing elements of the structure are generally designedto have the minimum impact on the useable space of the building and therefore are of the

minimum size possible. The size of the columns clearly depends on the height of the building

and the floor area supported. There is also an advantage in using higher grade steel and

considering an integrated fire resistant design (see Section 5).

The various options for columns are illustrated in Figure 1.1, and are:

H sections (generally with board protection).

Structural hollow sections

Partially encased columns.

Concrete-filled tubular sections.

(1)

(3) (4) (5)

(2)

Key:1. HE or UC section2. Structural hollow sections3. Partially encased H section4. Composite square hollow section column5. Composite circular hollow section column

Figure 1.1 Column options

Page 2


CreatedonFriday,

March18,

2011





3/8


and residential use

SS016a-EN-EU

2. H Sections

H sections are usually orientated so that the larger (primary) beams frame into the column

flange. This makes connection detailing considerably easier. H sections are the simplest

solution for columns. The same column serial size is normally chosen at all floor levels,

although the weight of the section can be varied. This approach simplifies column splices.

For economy and convenience of erection, columns are placed in lengths equivalent to 2 or 3

times the floor height. Two design tables for HE and UC columns are presented in Table 2.1

and Table 2.2 for concept design. An imposed load of 4 kN/m2

is used together with a total

permanent load (including self weight) of 4 kN/m2. The floor-floor height is taken as 4 m.

Table 2.1 Typical sizes of HE columns in braced frames. (Sizes shown are for lowest length ofcolumn, with reduction in mass for higher lengths)

Column GridNumber of Storeys

6 6 m 6 9 m 6 12 m 6 15 m

4 HE 220 B HE 280 B HE 240 M HE 260 M

6 HE 280 B HE 240 M HE 260 B HE 300 M

8 HE 300 B HE 260 M HE 300 M HE 320 M

10 HE 240 M HE 300 M HE 320 M HD 400 x 347

2 2All in S355 steel Imposed load = 3 kN/m plus 1 kN/m for partitions

Table 2.2 Typical sizes of UC columns in braced frames. (Sizes shown are for lowest length ofcolumn, with reduction in mass for higher lengths)

Column GridNumber of Storeys

6 x 6 m 6 x 9 m 6 x 12 m 6 x 15 m

4 203 UC 86 254 UC 132 254 UC 167 305 UC 198S275 S275 S275 S275

6 254 UC 132 254 UC 167 305 UC 198 305 UC 240S275 S275 S275 S355

8 305 UC 240 305 UC 198 305 UC 240 356 UC 235S275 S275 S355 S355

10 305 UC 198 305 UC 240 356 UC 340 356 UC 340S275 S355 S355 S355

2 2Steel grade as shown Imposed load = 3 kN/m plus 1 kN/m partitions

More detailed guidance on the initial sizing of columns is given in SN012.

Page 3


CreatedonFriday,

March18,

2011



http://www.access-steel.com/discovery/linklookup.aspx?id=SN012http://www.access-steel.com/discovery/linklookup.aspx?id=SN012


4/8


and residential use

SS016a-EN-EU

3. Partially Encased H Sections

Partial encasement between the flanges of the columns increases both their compressiveresistance and their fire resistance. A design table for partially encased HE sections is given

below for concept design. The maximum size of section is HE 450B in this table.

Table 3.1 Typical sizes of partially encased H sections in braced framesColumn Grid

Number of Storeys

6 x 6 m 6 x 9 m 6 x 12 m 6 x 15 m

4 HE 240A HE 240B HE 280B HE 300B

6 HE 240B HE 280B HE 340B HE 400B

8 HE 280B HE 340B HE 450B ---

10 HE 300B HE 400B --- ---

2 2All in S355 steel Imposed load = 3 kN/m plus 1 kN/m for partitions

Typically, partially encased columns can achieve 60 or 90 minutes fire resistance, depending

on the amount of bar reinforcement (refer to EC4-1-2).

4. Concrete Filled Structural Hollow Sections

Concrete-filled circular and square hollow sections are architecturally very important andachieve excellent composite properties due to confinement of the concrete infill. A typical

design table is shown in Table 4.1 for concept design.

Concrete-filled tubes also achieve excellent fire resistance because compression is transferred

to the cooler concrete and its bar reinforcement. Larger diameter tubes can be concrete-filled

from the base but most smaller tubes are filled from their top.

Table 4.1 Typical sizes of concrete-filled hollow sections in braced framesColumn Grid

Number of Storeys

6 x 6 m 6 x 9 m 6 x 12 m 6 x 15 m

4 219 x 10 219 x 12,5 273 x 12,5 323 x 12,5

6 219 x 12,5 273 x 16 323 x 16 355 x 16

8 273 x 12,5 323 x 16 355 x 20 406 x 16

10 323 x 12,5 355 x 16 406 x 20 457 x 20

Diameter (mm) thickness (mm)2 2

All in S355 steel Imposed load = 3 kN/m plus 1 kN/m for partitions

For fire resistance purposes, the minimum amount of bar reinforcement should generally

satisfy the limits in EN 1994-1-2. No reinforcement is generally required for 60 minutes fireresistance.

Page 4


CreatedonFriday,

March18,

2011





5/8


and residential use

SS016a-EN-EU

5. Fire Engineering of Columns

H columns are usually provided with passive fire protection, most commonly in the form ofboard systems for visual reasons. However, if required architecturally, they may also be

protected by intumescent paints.

Fire engineering of columns, i.e. eliminating the use of passive fire protection, can be used in

the following cases:

Buildings of low fire load.

External steelwork.

Integrated fire resistant design, using partially encased or concrete-filled hollow sections.

Water-filled tubular columns

Page 5


CreatedonFriday,

March18,

2011





6/8


and residential use

SS016a-EN-EU

6. Column Splices

Column splices are normally made about 1 m above the floor for ease of installation of thebolts. Four splice configurations are illustrated in Figure 6.1. For non-machined ends to the

columns, axial loads are transferred through splice plates with multiple bolts. Countersunk

bolts may be used where the flange is sufficiently thick, and where the bolt heads would affect

the finishes to the columns. An end plate detail may be used for lightly loaded columns.

Column lengths of 8 to 12 m are most economic, representing 2 or 3 storey heights.

(1) (2)

(3) (4)

Key:

1. Splice connection -shear transferred through bolts

2. End bearing connection with countersunk bolts

3. Splice connection dissimilar column sizes

4. End plate connection dissimilar column sizes

Figure 6.1 Column splice details

Page 6


CreatedonFriday,

March18,

2011





7/8


and residential use

SS016a-EN-EU

7. Vertical Bracing

Vertical bracing of V, X or K form is provided in the planes of the columns. The bracing

members are usually structural hollow sections, for V and K bracing (angles may also be used

but generally require more space in congested areas) or flats for X bracing.

Table 7.1 and Table 7.2 may be used for the initial design of vertical bracing in V or X form

in steel framed buildings of simple rectangular form, as a function of the length of the

building (exposed to wind) and number of storeys.

Table 7.1 Sizes of tubular bracing members in V form (diameter thickness)Length of Building (m)

Number of Storeys20 30 40 50

4 100 10 120 8 120 12,5 150 8

6 120 8 120 12,5 150 10 150 12,5

8 120 12,5 150 10 150 16 2 150 8

12 2 120 8 2 120 12,5 2 150 10 2 150 12,5

Bracing is at both ends of the building 2 means two braced bays at each end2

Floor-floor height is 4 m and wind load is 1 kN/m .

Table 7.2 Size of flat bracing members in X form (plate depth thickness)Length of Building (m)

Number of Storeys20 30 40 50

2 120 10 150 12 150 15 200 20

4 150 15 2 x 150 12 2 x 200 15 2 200 20

6 2 x 200 12 2 x 200 20 2 220 20 2 220 22

8 2 x 200 15 2 220 20 2 250 20 2 250 25

Bracing is at both ends of the building 2 means two braced bays at each end2

Floor-floor height is 4 m and wind load = 1 kN/m

Page 7


CreatedonFriday,

March18,

2011





8/8


and residential use

SS016a-EN-EU

Quality Record

RESOURCE TITLE Scheme Development: Vertical structure 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 28/7/06

TRANSLATED DOCUMENT

This Translation made by

Translated resource approved by

Page 8


CreatedonFriday,

March18,

2011




Documents

Scheme Development Vertical Structure for Multi-Story Blgds