www.tatasteelconstruction.com static files staticfiles section plates publications sections...

8/9/2019 Www.tatasteelconstruction.com Static Files StaticFiles Section Plates Publications Sections Publications Tata Steel-pa…

1/36

1

Document titleOptional subheadingSlimdek® residential pattern book

For multi-storey residential buildings


2/36

2

Introduction to Slimdek®

The Slimdek® constructi on system 1

Technical aspects of Slimdek®

Introduction 3

Asymmetric Slimflor® Beams (ASB) 3

Deep decking 4

Openings in the slab 5

Edge beams 6

Tie members 8

Connections 8

Columns 9

Discontinuous columns 10

Slimdek® in an unbraced structure 10

Fire resistance 11

Acoustic insulation 11

Attachment of cladding to edge beams 13

Service integration 14

The application of Slimdek®

Chosen building for study 15

Building form 16

Structural grids 17

Plan form and room layouts 18

Floor layout 22

Structural options 22

Material usage 28

Steel balconies and parapets

Types of balcony 29

Balcony attachments in Slimdek ® 30

Parapets and balustrade s 32

References 35 36

INTRODUCTION TO SLIMDEK ®

Figure 1.1 6 storey apartment block at Portishead Marina.

2


3/36

3

Figure 1.2 4 and 6 storey apartment buildings at Penarth Marina, Cardiff.

Steel framed construction has for some years

dominated the UK market for multi-storey

commercial buildings due to its cost, speed

and quality benefits. The proven values of

structural steelwork are now being taken

advantage of in the fast growing multi-storey

residential building market. The Slimdek®

floor system from Tata Steel offers particular

advantages in multi-storey residential

buildings. It provides a shallow floor depth

and can achieve 60 minutes fire resistance

with no added protection.

New research has also shown that Slimdek®

separating floors comfortably meet the

acoustic insulation requirements of the new

Part E (2003) Building Regulations.

Slimdek® floor system

Slimdek® is a fully engineered floor solution

that has been developed to offer cost-effective

shallow-depth floors for multi-storey steel

framed buildings with grids of up to 9m x

9m. The system simplifies the planning and

servicing of a building – resulting in significant

cost and speed of construction benefits.

Reductions in floor depth of up to 400mm

per storey, compared with conventional

construction, can be achieved using Slimdek®.

This offers the potential for extra floors to be

accommodated within a given building height

or alternatively a reduction in total building

height and consequent savings on envelope

costs.

Slimdek® floors achieve inherent fire resistance

of up to 60 minutes with no added fire

protection, reducing costs and speeding up

programme times. The relative light weight

of steel frames also leads to savings on

foundation costs.

Slimdek® is a shallow depth steel floor system thatoffers particular advantages in multi-storeyresidential buildings.

Slimdek® plan form and room layouts. Page 17.


4/36

4

Slimdek® residential pattern book Introduction to Slimdek ®

Figure 1.4

Slimdek® installation on site.

Figure 1.5

Typical column-free space achieved using

Slimdek®.

The key features of the system are:

Figure 1.3 Components of Slimdek®

Figure 1.6

Slimdek® used in a major renovation project

in Covent Garden, London.

● A shallow composite slab, which provides

excellent load resistance, diaphragm action

and robustness.

● An Asymmetric Slimflor® Beam (ASB), which

achieves efficient composite action without

the need for shear studs.

● An inherent fire resistance of up to

60 minutes with ASB fire-engineered

(ASB (FE)) sections.

● Lighter, thinner web ASBs, which can be

used unprotected in buildings requiring

up to 30 minutes fire resistance or in fire-

protected applications.

● ComFlor® 225 deep decking, which can span

up to 6.5m without propping (depending

on slab weight).

● Light weight construction.

Slimdek ® has been widely employed in the

commercial sector, and its advantages are

now being realised in residential applications.

It has been used in major residential projects

in Glasgow, Manchester, Cardiff, Portsmouth,

Bristol and London. Recent examples of

residential building projects are illustrated in

Figures 1.1 and 1.2.

Slimdek ® can be combined with other

components, such as rectangular hollow

sections (RHS) for columns and edge beams,

light steel infill walls and separating walls that

are directly supported by the composite floor,

as well as roof-top penthouses and mansard

roofs using light steel framing.

This brochure focuses on the practical

application of Slimdek ® in a mixed-use

residential and commercial building in an

urban area. This building type allows us to

examine a variety of design and detailing

issues. It is a six-storey building, with car

parking below ground and retail outlets at

ground-floor level. The same floor grid is

used for the car park and apartments, which

removes the need for a transfer structure.

Two plan forms are illustrated, to show

the versatility that exists with Slimdek ®

construction.


5/36

5

Table 2.2 is defined either by 35mm cover to

the ASB or 70mm topping to the decking (thistopping depth does not reflect any acoustic

requirement). A view through an ASB beam

and the composite slab is shown in Figure 1.3.

Slimdek® comprises a composite slab, formed

on ComFlor® 225 deep decking (designated

CF225 for clarity in some diagrams), which

is supported on the bottom flange of

Asymmetric Slimflor® Beams (ASB) – see Figure

1.3. The typical span capabilities of ASB beams

and deep composite slabs in Slimdek® are set

out in Table 2.1.

Asymmetric Slimflor® Beams

The Asymmetric Slimflor® Beam (ASB) is a

hot-rolled section in which the degree of

asymmetry between the widths of the top and

bottom flanges is approximately 60%. The top

flange has a raised rib pattern rolled into it to

provide composite action with the concrete

encasement, without the aid of a mechanical

shear connector.

A range of 10 ASB beams is manufacturedwith the properties given in Table 2.2. Fire-

engineered ASB beams (designated as

ASB(FE)) achieve 60 minutes fire resistance

without any additional fire protection,

whereas ASB beams achieve 30 minutes fireresistance, increasing to 120 minutes when

additional protection is applied to the soffit.

For construction the minimum slab depth in

Table 2.1 Typical span capabilities of

ASB beams in Slimdek®.

300 ASB (FE) 249 249 342 203 313 40 40 340

300 ASB 196 195 342 183 293 20 40 340

300 ASB (FE) 185 185 320 195 305 32 29 325 300 ASB 155 155 326 179 289 16 32 325

300 ASB (FE) 153 153 310 190 300 27 24 320

280 ASB (FE) 136 136 288 190 300 25 22 300

280 ASB 124 124 296 178 288 13 26 300

280 ASB 105 105 288 176 286 11 22 300

280 ASB (FE) 100 100 276 184 294 19 16 295

280 ASB 74 74 272 175 285 10 14 295

Mass Depth Width of flange Thickness Minimum Slab

Top Bottom Web Flange Depth

kg/m mm mm mm mm mm mm

Designation

Notes: ASB (FE) are fire engineeed sections

Table 2.2 Dimensions of ASB beams and minimum slab depths.

280 ASB 74 7.0 6.0

280 ASB 105 7.5 6.0

280 ASB 124 7.5 7.5*

300 ASB 155 9.0 6.0

300 ASB 196 9.0 9.0*

Beam Span Beam spacing

(m) (m)

280 ASB (FE) 100 6.0 6.0

280 ASB (FE) 136 7.5 6.0 300 ASB (FE) 153 7.5 7.5*

300 ASB (FE) 185 9.0 6.0

300 ASB (FE) 249 9.0 9.0*

Fire Resistance of 30 mins**

* Propped slab during construction

** Additional fire protection required for R60

Fire Resistance of 60 mins

Beam Designation

Slimdek ® supported by ASBs.

Technical aspects of Slimdek ®

Slimdek® comprises a composite slab, formed on deep decking, whichis supported on the bottom flange of Asymmetric Slimflor® Beams.


6/36

6

Deep decking

Deep steel decking (ComFlor® 225) spans

between the bottom flange of the ASB beamsand supports the wet concrete during

construction. The embossments formed in the

decking achieve excellent composite action

with the concrete, assisted by bar

reinforcement. Light mesh reinforcement is

provided in the concrete topping for crack

control purposes.

A cross section of ComFlor® 225 is shown in

Figure 2.1. Each decking element is 1.25mm

thick and 600mm wide and has special

attachment points for service and ceiling

hangers. The ComFlor® 225 decking is

provided with end diaphragms and cut-outs

to allow placement and retention of the

concrete around the ASB beams, as illustrated

in Figure 2.2.

A cross-section through the composite slab in

Figure 2.3 shows the positioning of the bar

reinforcement. A minimum concrete cover of

80mm over the decking ensures fire resistance

and acoustic insulation, although it may be

necessary to increase this cover depending on

the size of the ASB selected (see Table 2.2). The

typical slab depth for residential applications is

300mm to 330mm, which creates a floor depth

of approximately 400mm when combined

with acoustic insulating layers and a

suspended ceiling. The typical span

capabilities of deep composite slabs using

ComFlor® 225 decking are presented in Table

2.3. Temporary propping is not generally

required for spans up to 6m. Spans may be

increased to 9m if two lines of temporary

props are used during construction. Services

can be passed through openings in the ASBbeams and between the ribs of the slabs.

Slimdek® residential pattern book Technical aspects of Slimdek ®

195

30

30

40

37

30

240

30

7

8

33

1 5 35

600

100 400

35

100

Horizontal

ribs

Vertical

embossments

Service hanger

(typical detail)

Figure 2.1 Cross-section through ComFlor®225 deep decking showing service attachments.

50 nominal bearing

15

Slab

topping

225

End diaphragm

Deck cut-out50

Cover

to top

of beam

Figure 2.2 Detailing of ComFlor® 225 decking at ASB beams.

. .

l l l l

ll

l l .. . ll l l l l l .

16 16 16 20 20 25 32 N.A.

16 16 20 20 20 25 32 32

16 20 20 20 25 25 32 32

5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0

Bar size iameter, mm or Span o s a m

No propping Single line props required Double line props required

generally

Blue area shows propping requirements for each slab.

N.A. = not generally applicable because natural frequency of slab is less than 5Hz.

Slab depth (mm)

300

320

340

Propping

Table 2.3 Reinforcement requirements (bar diameter) in deep composite

slabs for 60 minutes fire resistance.

16, 20, 25 or

32 diameter

50

Mesh reinforcement

Main reinforcement

Axis

Figure 2.3 Cross-section through composite slab.


7/36

7

Openings in the slab

Opening may be positioned between the ribs

of the decking without affecting the load-bearing capacity of the slab. The maximum

width of these openings is 400mm. Wider

openings may cut through one or more ribs,

in which case it is necessary to reinforce the

slab to distribute the forces to the adjacent

ribs. A standard edge trim is pre-fixed as a box

around the opening.

The maximum recommended size of

opening is 1000mm x 2000mm before

additional trimmer beams are required.

Details of permitted openings and additional

reinforcement around the openings are

presented in Figure 2.4.

Openings next to columns should be detailed

to avoid the ASB and tie members. For these

cases, the close proximity of the openings

to the ASB does not affect the composite

strength to the same degree as when

openings occur in the span. As a consequence,

some relaxation of the dimensions given

in Figure 2.4 is possible. The recommended

minimum distance from a grid line to the

centre-line of a 150mm opening is 225mm,

or 200mm for a smaller opening. It is also

possible to accommodate a minor notch in

the bottom flange of the ASB near the end

connection to provide an opening for a service

pipe, but this should be detailed in order to

allow for fabrication before delivery to site. A

detail showing the provision of a service pipe

close to an ASB near a column is presented

in Figure 2.5.ASB

Setting out level

CF225

decking

Meshreinforcement

Column (UKC)

A

Service pipe

(max. 150 dia.)

Welded

stiffener

Welded stiffener

Service

pipe

225 min.

225 min.

Connecting

bolts

Section A - A : Plan view

Tie beam

Tie beam

A

Figure 2.5 Provision of a service pipe close to an ASB in a Slimdek ® floor near to a column.

ASB

beam

Opening

1000

T12 bar x1500 long

Minimum A142mesh throughout

400

Centre-lineof ribs

Opening

B

B

A A

Additionalbottomreinforcementto adjacent ribs(by engineer)

beam span/ 16*500

1000

300

beam span/16for compositebeam design

2000

beam span/16for compositebeam design

Additional topreinforcement

Edge trimfixed as 'box'

Section A - A

Curtailedbar

Transversebar

Temporaryprop

Section B - B

Enddiaphragm

Transversebar

Temporaryprop

Temporaryprop

Temporaryprop

Edge trimfixed as 'box'

ASBbeam

Figure 2.4 Detailing of openings in the slab in Slimdek®.


8/36

8

Edge beams

If the configuration of windows and cladding

allow then a downstand beam can be usedas an edge beam. However, where this is

not possible then two alternative forms of

edge beam are recommended – ASB or RHS

(Rectangular Hollow Sections).

ASB beams may be designed in two alternative

configurations:

1. ASB encased in concrete for fire resistance

and effective composite action, as illustrated

in Figure 2.6. In this case, the edge of the

slab is detailed at 200mm from the centre-line

of the beam to allow for fixing of the edge

trim, and placement of the concrete and L-bar

reinforcement.

2. ASB partially encased in concrete, as

illustrated in Figure 2.7. In this case, no

composite action is developed and the fire

resistance is reduced to 30 minutes, unless

additional protection is applied. The edge of

the slab may be detailed at 100mm from the

centre-line of the beam (actual distance is half

the flange width or 95mm). To anchor the slab,

an L-bar is placed in holes pre-drilled in the

ASB. The edge trim allows for a thin concrete

topping.

The advantage of the second option is that

any eccentricities in the column connection

are reduced. However, the disadvantage is that

the projecting flange of the ASB has to be cut

away (depending on the cladding system), and

additional insulation is required to reduce

‘cold bridging’.


Figure 2.7 Partially encased ASB details at edge beam.

Figure 2.6 Encased ASB details at edge beam.

l

L-bar (10 )

at 300 centres A142 mesh

3 0

20

bolt hole

Mineral

wool

infill

ASB cut away by 55 (if necessary)

End diaphragm

1 5 0

3 0

A142 meshEnd diaphragm

Edge

trim

1000

50

200

10 mm dia. additional

L-bars at 300 centres

55

l l

l

l

ll


9/36

9

Beam span (m) < 6.0 7.0 8.0 9.0

Non-composite 200 x 150 x 8 200 x 150 12.5 or

250 x 150 x 10300 x 200 x 10 N.A.

Composite 200 x 150 x 8 200 x 150 x 10 200 x 150 x 12.5

Data for 6m span slab onto RHS

200 x 150 x 12.5

Proprietary

battened

raft floor

Separating strip

Acoustic sealant

Deflection head

Resilient bars

timber battens,

or metal frameceiling

15 min.

plasterboard

resilient strip

Acoustic sealant

12.5 plasterboardDeep composite

metal deck floor

Rigid insulation in

external cavity

Light steel stud wall

with 2 layers of gypsum board

External brickwork tied to inner stud wall

Trapezoidalprofile

Cavity

Optional additional

insulation (to reduce

U value)

Halfen or similar

stainless steel

brickwork support

Cavity barrier to

floor/wall junction

Figure 2.8 Non-composite RHS edge beam supporting brickwork.

Minimum Slab Depth (mm)+Designation

of RHS

Thickness

(mm)

Mass *

(kg/m)

Depth

(mm) Non-composite Composite

8.0 215 295 29510.0 215 295 295

200 x 150

(240 x 15 plate)12.5 215 295 295

8.0 265 295 335

10.0 265 295 335250 x 150

(240 x 15 plate)12.5 265 295 335

8.0 315 300 N.A.

10.0 315 300 N.A.300 x 200

(290 x 15 plate)12.5 315 300 N.A.

* including 15 mm plate

Slab depth applies to R60 fire resistance

7079

91

76

87

100

94

100

126

Table 2.4 Section dimensions of RHS Slimflor® edge beams.

Table 2.5 Approximate section sizes of RHS edge beams supporting brickwork.

Rectangular Hollow Sections (RHS) may be

used as either composite or non-composite

edge beams. Non-composite beams areillustrated in Figure 2.8. RHS edge beams

provide an attractive option because of

their ease of detailing at the façade line.

Furthermore, their high torsional stiffness

facilitates eccentric connections, for example,

of cantilever balconies. When the edge beam

is used only as a cladding support, torsional

stiffness is still required because of the

eccentric load from the cladding.

For composite construction, shear connectors

may be welded to the top flange of the RHS to

increase its spanning capabilities by composite

action. However, the slab depth needs to

be taken as 85mm above the RHS section,

which makes the 300mm RHS impractical in

composite construction (see Table 2.4). The

sizing of the RHS sections generally depends

on the orientation of the slab and the cladding

load. For scheme design purposes, the RHS

sizes given in Table 2.5 may be used.


10/36

10

At RHS columns, it is often difficult to attach

ASBs on adjacent sides. This may be achieved

by using alternate extended and flush end

plates, as illustrated in Figure 2.12.

This approach is only applicable for columns

with a minimum width of 200mm. In other

cases, welded T-stubs may be used to attach

the beams.

flanges to avoid cutting back the ASB section.

A typical external UKC column connection

with an ASB edge beam is shown in Figure

2.10, and in Figures 3.15 and 3.16.

For RHS columns, connections can be made

using Flowdrill or Hollo-bolt connections.

Hollo-bolts require the formation of a hole

of 1.7 x bolt diameter. As a result of this, the

maximum diameter is generally 20mm to

allow for edge distances and gaps. A typical

external RHS column connection with a RHS

Slimflor® edge beam is shown in Figure 2.11.

Tie members

Tie members are required to provide

robustness by tying columns at each floor.Generally, tie members are in the form of

inverted Tees. Smaller UKB or RHS sections

with a welded plate are often used where the

tie beam supports other local loads. Figure

2.9 illustrates a typical Tee section; this allows

for sufficient placement of a Z-section where

the deck layout is not in multiples of 600mm.

The depth of the Tee is taken as not less than

span/40 in order to avoid visible sag.

The Tee section does not participate in

resisting loads applied to the slab, so

reinforcement is placed in the ribs adjacent

to the Tee. This does not generally require fire

protection, where it is partially encased in the

slab. The Tee may be attached by an end plate

to the column web or to a stiffener located

between the column flanges. This same

stiffener may act as a compression stiffener in

a moment-resisting connection to the major

axis of the column.

Connections

Slimdek ® has been developed primarily as

a flooring system for braced steel-framedbuildings. Typically, the beams and slabs

are analysed as simply supported elements.

Continuity, which is inherent within the

system, is only partially used for the

serviceability criteria. It is possible to use the

ASB beam as part of a sway frame, provided

extended end plate connections are used.

In this case, columns must be analysed for

combined bending and compression.

Beam-to-column connections with ASB or

RHS beams should generally be made by full

or extended end plates in order to ensure

adequate shear and torsional resistance due

to out-of-balance loads (primarily during

construction). For UKC section columns, beam-

to-column connections are generally made

to the column flange. Where connections are

made to the column web, it may be necessary

to weld a plate between the tips of the column

600

Mesh reinforcement

Reinforcementbar

Decking cut to suitsetting-out requirement

ASB bottom flan ge Z section Tee sectioncut from

UKC or UKB

Figure 2.9 Inverted Tee section as a tie member.

ASB end plate

ASB edge beam

Perimeter UKC

ASB edge beam

ASBinternalbeam

Figure 2.10 External UKC section column connection to ASB edge beam.



11/36

11

Figure 2.12 End plate connections to RHS columns.

50 cavity

Non-loadbearing

light steel stud

Resilient mineral wool

separating RHS and

light steel section

2 x 12.5 plasterboard

Insulation board

RHS column

Vertical channel

(to attach wall ties)

Figure 2.13 RHS column incorporated in façade wall (plan section).

Figure 2.11 External RHS column connection to a RHS Slimflor® edge beam.

Columns

Universal Column (UKC) sections are

recommended for internal columns because of

their ease of connection. Rectangular Hollow

Section (RHS) columns can be used for fireresistance or for architectural reasons. For

example, RHS columns can be contained in

the separating or façade walls, as illustrated in

Figure 2.13.

A

a) Side view of ASB beam

15 end plate

Flange

cut away

A

b) Cross-section A - A

Flowdrill orHollo-bolts

200 RHS

column

200 RHS

column

Flowdrill orHollo-bolts

Hollo-boltsPerimeter RHScolumn (or UKCwith plates weldedacross flange tipsfor edge beamconnections)

RHS Slimflor®

edge beamwith 15 thick flange plate

Extendedend plate

InternalASBbeam


12/36

12

The moment capacity of typical extended end

plate connections is summarised in Table 2.6

(moment capacities for specific ASB weights

may be obtained from the Slimdek ® Manual).

These moment capacities are relatively

insensitive to the ASB section size, as bending

of the end plate controls their design.

The design of ‘wind-moment’ frames is a

special case where the connections are

treated as pinned under vertical load and

moment-resisting under wind loading. As a

simple rule, the maximum number of storeys

permitted in a ‘wind-moment’ frame should

not exceed the number of columns in the

direction in which the wind forces act (up to amaximum of six storeys). Therefore, for wind

acting on the front face of a building with four

columns across the width, the maximum

height is four storeys.

For a rectangular plan building with wind

acting on the short length, there are

potentially more columns to resist the wind

loads along the building, and the maximum

height recommended is increased to six

storeys, provided that the columns are

orientated so that their stiffer direction isalong the building length. In this second

orientation, vertical bracing can be eliminated

in the façades, leading to large fenestrations

and freedom of space planning.

Slimdek ® in an unbraced structure

Vertical bracing can be eliminated in a

structure with Slimdek ® floors by designing theconnections between the ASBs and the

columns as moment-resisting. Where UKC

columns are used, these connections should

be made to the column flanges. Extended end

plates increase the effective depth of the

connection and increase its moment capacity.

A typical extended end plate connection is

shown in Figure 2.15. For detailing purposes,

dimension A should be taken as 44mm for

ASB280 and 62mm for ASB300.

RHS columns may be used, but the moment

capacity of beam end connections are

generally less effective than for UKC sections,

except for the thicker wall sections.

Table 2.6 Moment capacities (kNm) of extended end plate connections

200

d

t f

50

120

300

10

75

75

A

50

40t f

Figure 2.15 Extended end plate connection

to an ASB beam.

Discontinuous columns

Columns can also be designed as storey-high

elements and attached to the flanges of theASB, as illustrated in Figure 2.14. This unusual

configuration is possible in medium-rise

buildings because the modest compression

forces can be transferred through the thick

web of the ASB to the concrete encasement.

In these cases, moment continuity can be

developed in the ASB to optimise

its performance. For more heavily loaded

columns, vertical stiffeners would be required

in the web of the ASB. When adopting this

approach, particular care and attention must

be paid to the design and detailing, especially

to ensure frame stability and resistance to

progressive collapse (through horizontal and

vertical tying, or by key element design).

Figure 2.14 ASB beams continuous over storey-high

RHS columns in medium-rise buildings.

Column size kg/m ASB280 ASB300

203 UKC

x 46 81 85

x 52 86 90

x 60 91 95

x 71 92 97

254 UKC x 73 92 97

x 89 92 97

Data: 15 end plate in S355 steel and M20 bolts


15 end

plate

A

A

RHS tie

ASB

150 SHS

column

a) Side view of ASB beam

b) Cross-section A - A

150 SHS

column

150 SHS

column

150 SHS

column

RHS tie

ASB


13/36

13

Fire resistance

The fire resistance of the ASBs is achieved by

partial encasement in the composite slab.Generally, 60 minutes fire resistance can be

achieved by ASB sections, increasing up to 120

minutes if board materials, a suspended

ceiling or intumescent coatings, protect them.

The fire resistance of the deep composite slab

is achieved by bar reinforcement of the

minimum sizes shown in Table 2.7. The axis

distance defines the distance from the centre-

line of the reinforcing bar to the soffit of the

decking (see Figure 2.3). Mesh reinforcement

is placed in the topping at a minimum top

cover of 15mm. The reinforcement detailing

requirements are illustrated in Figure 2.3.

Acoustic insulation

Separating floors in Slimdek ® are easily

capable of providing the acoustic insulation(both airborne and impact) required to meet

the new Part E (2003) Building Regulations.

When combined with the prescribed floor and

ceiling treatments the floor has been able to

achieve Robust Detail (RD) status (E-FS-1). RD

status means that post-completion testing of

the floor is not required. A typical cross section

through a beam and slab showing the various

layers is shown in Figure 2.16. Table 2.8

illustrates the excellent performance in robust

detail in-situ tests compared to the

requirements given in Part E of the Building

Regulations.

Masonry or double-leaf light steel separating

walls can be used in conjunction with the

Slimdek ® floor. Double–leaf walls are generally

recommended because of the ease and speed

of construction and the elimination of wet

trades on site. Typically, this type of wall

comprises two leafs of studs (each 50 to 70mm

deep) separated by a layer of mineral wool.

The outer faces of the studs are fixed to double

layers of plasterboard, to give an overall

thickness of around 250mm. Care should be

taken to ensure an adequate cavity width, and

adequate densities for the materials used.

Specialist manufacturers have produced a

number of proprietary wall and detail

solutions.

Table 2.7 Detailing requirements for deep composite slabs.

280 ASB 100

18 thick tongued and grooved

chipboard walking surface (or similar)

Proprietary batten

with integral foam strip

Single skin 12.5 thick

plasterboard suspended ceiling

Proprietary

resilient bars

Concrete floor slab with

ComFlor®225 deep decking

Figure 2.16 Cross-section through ASB beam showing acoustic insulating layers.

Parameter Fire resistance (mins)

60 or less 90 120

Min. slab depth 295 mm 305 mm 320 mm

Min. bar diameter 16 mm 20 mm 25 mm

Axis distance to bar 70 mm 90 mm 120 mm

Min mesh size in topping A142 A193 A252


14/36

14


Table 2.8 Acoustic performance of Slimdek®.

Separating strip

Acoustic sealant

Platform floorProprietarybattenedraft floor

Separating strip

Acoustic sealant

12.5 plasterboard Resilient bars ortimber battens

Deflection head

Acoustic sealant

Deep compositesteel decking

12.5 plasterboardceiling on proprietary

metal frame ceiling

1 layer of 15 plasterboardor other fire-stopping

material laid flat between ASBand light steel channel

Light steel frameseparating wall

Figure 2.18 Acoustic detail of ASB beam and light steel separating wall.

Details of the attachment of a separating wall

to an ASB beam are i llustrated in Figure 2.18.

A ‘deflection head’ allows for relative

movement between the ASB and the

separating wall. Note that board present at

the top of the wall is needed for fire as well as

acoustic purposes.

One of the most crucial features with this type

of wall is the interface between the wall head

and the soffit of the slab, particularly when the

deck ribs do not run parallel to the wall. The

attachment of a light steel separating wall to

the soffit of a composite slab with ComFlor®

225 decking is illustrated in Figure 2.19.

Profiled mineral wool inserts are required toprevent both sound and fire passing through

the voids in the deck. Board beneath these

inserts also serves both fire and acoustic

purposes. When this detail is properly achieved

the wall can be expected to pass

Part E requirement.

More information on expected acoustic

performance and typical construction details

can be found in the accompanying SCI

Publication P336 Acoustic Detailing for

Multi-Storey Residential Buildings.

Additional mineral wool inceiling void around junction

Pack withmineral wool

2 layers of 19 mmgypsum board

12.5 mm plasterboardon proprietry metal frame

Deep compositesteel decking

Separating strip

Acoustic sealant

Platform floor Proprietarybattenedraft floor

Separating strip

Acoustic sealant

Acousticsealant

Light steel frameseparating wall

Figure 2.19 Acoustic detail of separating wall transverse to composite slab.

Part E 45 62

Robust Detail 47 57

Slimdek ® Performance (E-FS-1) (Range) 50-64 24-46

(Mean) 56 38

Acoustic Test Data (dB)

Airborne sound reduction

Impact sound

DnT,w + Ctr L,nT,w

>_

>_


15/36

15

Proprietary battenedraft floor

Separating strip

Acoustic sealant

Deflection head

Resilient bars,timber battensor metalframe ceiling15 min.

plasterboard

resilient strip

Acoustic sealant

12.5 plasterboard

Deep compositemetal deck floor

Rigid insulationin externalcavity

Light steel stud wall with2 layers of gypsum board

Externalbrickworktied to innerstud wall

Halfen orsimilar stainlesssteel brickworksupport

Cavity

Cavity barrierto floor/wall

junction

Optionaladditionalinsulation(to reduceU value)

Proprietary battenedraft floor

Claddingsheet

Cladding railon anglebrackets

Sheating board

Breatherpaper

i i il

i

l l li l

i ll i ll

i i i l ii l

i

l

ii

i l

. l

il ili

il

ili

i l

i i

i l i i l i l i

ii

l ill i

i . l

i

l ili l ll

i i i l i

ii l

i

i

Deflectionhead Resilient bars,

timber battensor metal frameceiling

15 min.

plasterboardresilient strip

Acoustic sealant

12.5 plasterboard

Deep compositemetal deck floor

i

i

i i

i l

i

ilii

lilii .

l

ili i

i l

. l

il

i i i l ii l

i

i l ll il

li

i i ll

li il i l

l i

i

i ill

i

i li i l

i l i

l

i

l i

l i ill

i

Fixing railon packers

Sheathing board

Platform floor Slimdek floor

Light steel framenon-loadbearingstud wall

Rigid insulationmaterial

Fire break

Polymer basedrender

15 drainedcavity

Acoustic sealant

12.5 plasterboard

Deep compositemetal deck floor Resilient bars,

timber battensor metal frameceiling

Acoustic sealant

Separating strip

Optional additional insulation

Drained 15cavity

Clay tilecladdingsystem

15 min. plasterboard

Deflection head

Non-loadbearinglight steel frame stud wall

Rigid insulationBreatherpaper (withoptionalsheathing board

behind)

iili

il

ili i .

lili i

i l

. l

il

Proprietarybattened

raft floor

Cladding attachments depend on the type

of cladding used and the type of edge beam.For encased ASB beams, the centre-line of the

ASB is detailed at 200mm from the edge of the

slab (see Figure 2.6).

Figure 2.20 Detailing of brickwork support by ASB beams.

Figure 2.21 Insulated render cladding attachment to ASB beams.

Figure 2.22 Rain-screen cladding attachment in Slimdek ®.

Figure 2.23 Brick-tile cladding attachment in Slimdek ®.

More detail on cladding systems and their

attachments is given in Figures 2.20 to 2.23.For details on cladding attachments to RHS

edge beams, see Figure 2.8.

Attachment of cladding to edge beams


16/36

16

Service integration

● Openings in the slab for pipes and service

risers.

● Openings in the web of the ASB for

horizontal service distribution in the floor

zone.

● Trays embedded in the slab for horizontal

distribution of electrics or small diameter

pipes in the surface of the slab.

Large openings can be formed between the

ribs of the decking and through openingsin the ASB beams (subject to effective fire

compartmentation). Electrical trays should be

positioned to align with the ribs of the

decking so that they observe fire resistance

and acoustic insulation requirements

(see Figure 2.24).

Opening in slabHorizontalservice tray

150 max.

320 max.

Opening in ASB 160 max.

300 max.

60 min.

50 max.

80 min.

Mesh

T12 bar

ASB bottom flange

Figure 2.24 Service openings and electrical trays in Slimdek ®.



17/36

17

Our example building is a six-storey structure

with a roof-top penthouse, illustrated in Figure

3.1. The building design could be extended to

ten-storeys without significant modifications

to the structure. The interior of the building

may be configured with apartments on

either side of a central corridor, referred to

as the ‘deep plan’ form, or with apartments

configured across the full width of the building

around an access core, referred to as the

‘shallow plan’ form. See Figures 3.5 and 3.6.

The building is be adapted for mixed use,

making provision for retail uses at ground floor

(by increasing the floor-to-floor height) and for

car parking at basement level. The length of

the building is not defined, as the plan forms

are repeatable.

The flexible use of space provided by Slimdek ®

is illustrated in Figure 3.2.

The building considered has three distinct

levels:

● Below-ground car-parking.

● Retail or office level at first floor.

● Residential floors above.

The structural grid adopted is dictated by the

car park level, to avoid the use of an expensive

transfer structure. This is based on a three-

car bay (7.5m wide) along the façade, and

columns at 4.8m, 6.7m and 5.0m respectively

across the building (deep plan) or 3.9m, 7.2m

and 4.8m (shallow plan) to allow for sufficient

vehicular access.

The application of Slimdek ®

Flat Flat

Car Park

Flat Flat

Flat Flat

Flat Flat

Central

Corridor FlatFlat

Retail

Penthouse

Central

Corridor

Central

Corridor

Central

Corridor

Central

Corridor

Figure 3.1 Deep plan form – cross-section through building.

This section examines a typical mixed-use residentialbuilding in steel using Slimdek ® construction.

Figure 3.2 Flexible space using Slimdek ®.


18/36

18

Light steel walls

Light steel walls are used for:

● external walls to create a ‘rapid dry envelope’;

● compartment or separating walls between

apartments;● internal walls within apartments.

Building form

The steel-framed apartment building has

the following characteristics:

Prefabricated modules

Bathrooms are assumed to be prefabricated

modules set into the slab to avoid mis-alignment

of the floors.

Minimal foundation costs

Foundations are located directly below the

columns. The lightweight steel construction

minimises foundation costs.

No limit on building height

The building is six storeys high (plus penthouse and

car park levels). The ground floor can be adapted

for retail use. There is no limit on building height

when using Slimdek®, but four to ten storeys

is the sensible range for this type of residential

construction. Penthouse apartments are located at

roof level.

Utility servicing

Servicing is rationalised by vertical risers in the

core and horizontal routes through the floor slab.

Acoustic insulation

Excellent acoustic insulation is achieved by the

Slimdek® floor with its resilient layers.

Slimdek® residential pattern book The application of Slimdek®


19/36

19

7.5m 7.5m

6.7m

5.0 m

4.8m

5.4m

Figure 3.3 Structural grid as dictated by

car park level.

Structural grids

Façade materials and finish

External brickwork cladding with a light steel stud

inner skin is assumed for the steelwork designs,

although a variety of façade materials may be used.

(Ground supported brickwork is not practical abovefour storeys.)

Minimal floor depth

Using Slimdek®, the floor depth (including a

suspended ceiling and battened floor) is typically

400mm.

Optimum structural grids (i.e. column layout)

differ greatly between applications:

● Car parks – grids are normally based on 5m

(two-car spaces) or 7.5m (three-car spaces)

as in Figure 3.3.

● Residential buildings – grids are often based

on multiples of 600mm (4.2m being efficient

for studios).

● Commercial buildings – use grids based on

multiples of 1500mm (6m, 7.5m and 9m

being common column spacings).

From this it is apparent that, for a mixed-use

building, the column grids will not align

unless either the arrangement of car parking

space or residential accommodation is

modified. Alternatively, a steel or concrete

transfer structure may be designed to transfer

loads from the super-structure to the columns

of the car park substructure. In this case,

it is important that the superstructure is

sufficiently light so that the transfer

structure is not made deeper – increasing

foundation costs.

A repeatable floor plan area

A repeatable floor plan area (for either plan form)

of approximately 20m x 16m is accessed from a

single braced core. Spans of 4.8m to 7.5m achieve

a sensible layout of apartments and rooms, which

may be reconfigured independently of the beam

lines. This allows a range of apartments with floor

areas from 60m2 to 120m2 to be created.


20/36

20

Deep plan form

The deep plan form has the following features:

● Columns are located at 7.5m and 5.4m along

the façade.

● Columns are located at 5.0m, 6.7m and 4.8m

across the plan form of the building.

● A 2.1m-wide corridor is provided along the

building.

● Columns are generally located in the

300mm-wide separating walls between

apartments.

● An alternative lift location may be

introduced (see Figure 3.10).

● The ratio of habitable:gross floor area is

about 85% per residential floor.

● Apartments of approximately 50m2 and

65m2 floor area are provided, which are

each suitable for two and four people

respectively.

● A total of 14 car parking spaces is provided

(including two disabled spaces) for the five

residential and penthouse levels. The car

parking lies fully within the building depth.

● The penthouse level is accessed via the

stairs and provides two 68m2 apartments,

each suitable for four people.

● A retail area of 880m2 is provided.

Shallow plan form

The shallow plan form has the following

features:

● Columns are located at 7.2m and 6.3m along

the façade.

● Columns are located at 3.9m, 7.2m and 4.8m

across the plan form.

● Columns are all located in the separating

walls between apartments.

● Three apartments are accessed directly from

each stair/lift area on each residential floor.

● The ratio of habitable:gross floor area is

about 85% per residential floor.

● Apartments of approximately 50 and 75m2

floor area are provided, which are suitable

for two and four people respectively.

● A total of 13 car parking spaces are provided

(including two disabled or wide spaces) for

the five residential and penthouse levels.

The car parking projects 3.9m to the rear of

the building.

● A retail area of 640m2 is provided.

● The penthouse level is accessed via the

stairs and provides two 73m2 apartments,

each suitable for four people.

Plan form and room layouts

Two plan forms are considered, which are

presented in the following illustrations:

1. A deep plan form with apartments on either

side of a central corridor.

2. A shallow plan with apartments across the

full depth of the building.

The building is extendable horizontally by

repeating the shallow plan form, although

with the deep plan form it is possible to serve

three units with only two stairs or lift areas (see

Figure 3.4).

Figure 3.4 Repeatable floor plan with three units sharing two lift/stair areas.



21/36

21

BedroomBedroomKitchen/ dining/living

BedroomBedroomBedroomBedroom

1 BED FLAT 1 BED FLAT


Kitchen/ dining/living



Figure 3.5 Deep plan form – Layout of apartments.

Bedroom

1 BED FLAT

2 BED FLAT




Bedroom Bedroom Bedroom

2 BED FLAT

Bedroom

Figure 3.6 Shallow plan form – Layout of apartments.


22/36

22

Retail UnitRetail Unit

Figure 3.7 Deep plan form – car parking level.

Figure 3.8 Deep plan form – layout of retail level.



23/36

23

1 BED FLAT

BedroomBedroom Kitchen/ dining/living

Bedroom

2 BED FLAT

BedroomBedroom





Figure 3.10 Deep plan form – layout of apartments for alternative lift location.


Bedroom BedroomBedroomKitchen/ Dining/Living

Bedroom Kitchen/ Dining/Living

Figure 3.9 Deep plan form – penthouse level.


24/36

24

Floor layout

The structural layout of the floor in both plan

forms comprises 280 ASB beams spanning up

to 7.5m, and a deep composite slab spanning

up to 7.5m between the beams (spans in

excess of 6m require temporary propping in

normal-weight concrete). The slab depth isnominally 300mm. Shallow decking may be

supported off the bottom flanges to create a

shallow slab in the core area, providing an

additional zone for servicing within the floor.

Structural options

The various structural layouts of the building

are presented in Figures 3.11 to 3.15. In a

braced frame, longitudinal bracing is provided

at suitable locations in the façade, depending

on fenestration positions and sizes. Bracing

locations can be difficult to design in highlyglazed façades.

The advantage of a wind-moment frame

design is that vertical bracing can be omitted

in the longitudinal direction of the building,

which allows full-height glazing to be used

throughout. Alternatively, vertical bracing has

to be located between columns in separating

walls, in the façade, or around the core.

The disadvantage of the wind-moment frame

option is that it is not generally appropriate for

buildings of more than six storeys, and

columns are often heavier than in a braced-

frame design. Moment continuity is achieved

by using extended end plates welded to the

ASB or RHS beams.

Tie members (generally in the form of Tees) are

provided parallel to the decking, in the

absence of the ASB beams. At the perimeter of

the buildings, ASB beams or RHS sections with

a welded plate may be used. The centre-line of

the ASB beams is offset by 200mm from the

edge of the slab to allow for access of the edgetrim (see Figure 2.6). The connection is detailed

as in Figure 3.16. Alternative details not

requiring this eccentricity, but requiring

additional fire protection to the exposed ASB,

are presented in Figures 2.7 and 3.17. The

equivalent detail of an RHS edge beam to a

RHS column is not eccentric, as shown in

Figure 3.18. For this reason, RHS edge beams

are preferred.

At internal columns using smaller RHS sections,

the ASB will project outside the column, in

which case bolted connections may be made

to plates welded to the RHS, as shown in

Figure 3.19.

The columns are detailed to be located within

a 300mm separating wall, which consists of

two 100mm C-sections with a 40mm gap, and

two layers of fire-resisting plasterboard. The

maximum column width is therefore 200mm

(i.e. 203 UKC or 200 x 200 RHS or 300 x 200

RHS). If the column size is increased to 254

UKC, an intumescent coating should be used

to provide adequate fire resistance. Where

columns align with partitions, exposed RHS

columns may be used, which are fire protected

by intumescent coating or filled with concrete.

An example of the use of RHS columns located

in a light steel separating wall is illustrated in

Figure 3.20.



25/36

25

Figure 3.11

Structural layout for deep plan building – ASB edge beams and UKC columns.

Figure 3.12

Structural layout for deep plan building – ASB edge beams and UKC columns - propped.

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

280 ASB 100

2 8 0 A S B 7 4 o r

2 0 3 U K C 4 6 + p l a t e

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

280 ASB 100or 254 UKC 89 + plate

2 0 3 U K C

4 6 S 3 5 5

5 0 0 0

2 8 0 A S B 7 4

2 5 4 x 1 4 6 U K B 3 1

S 2 7 5

1 5 2 x 8 9 I

5400

280 ASB 100

300 deepNWC slabon CF225decking

2 2 0 0

280 ASB 100

4

8 0 0

254 x 146 UKB31S275

280 ASB 74

2 8 0 A S B 7 4

2 8 0 A S B 7 4

2 8

0 A S B 7 4

CF225

CF51

Stair Lift

Void

CF51

CF51

152x89 I 2 8 0 A S B 7 4 o r

2 0 3 U

K C 4 6 + p l a t e

2 8 0 A S B 7 4

w i t h a n c h o r e d r e - b a r s

o r 2 0 3 U K C 5 2 + p l a t e

1 6 5 x 1 5 2 T

@ 2 0 k

g / m S

2 7 5

1 6 5 x 1 5 2 T

@ 2 0 k g / m S

2 7 5

7500 7500 7500

6 7 0 0

2 0 3 U K C

8 6 S 3 5 5

2 0 3 U K C

8 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6

S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

5 2 S 3 5 5

2 0 3 U K C

5 2 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

7 1 S 3 5 5

2 0 3 U K C

7 1

S 3 5 5

2 0 3 U K C

7 1 S 3 5 5

2 0 3 U K C

7 1 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5 280 ASB 100

or 254 UKC 89 + plate

280 ASB 74280 ASB 100


280 ASB 74or 204 UKC 52 + plate280 ASB 100



P P

P = Decking propped at construction stage

5400

4 8 0 0

2 8 0

A S B

7 4

2 8 0 A S B

1 0 0

2 8 0

A S B

7 4

CF225P

165 x 152 T

@20 kg/m S275

165 x 152 T

@20 kg/m S275

2 8 0 A S B

1 0 0

165 x 152 T

@20 kg/mS275

2 8 0

A S B

7 4

2 8 0 A S B

1 0 0

7500

2 8 0

A S B

7 4

o r 2 5 4 U K C 8 9

+ p

l a t e

2 8 0 A S B

1 0 0

o r 2 5 4 U K C 1 0

7 + p

l a t e

7500

280 ASB 74


280 ASB 74

with anchored re-barsor 203 UKC 46 + plate

2 5 4 x 1 4 6

U K B 3 1

S 2 7 5

1 5 2 x 8 9

IVoid

Stair Lift

C F 5 1

CF51 CF51

2 2 0 0

4 8 0 0

2 8 0

A S B

7 4

300 deepNWC slabon CF225

decking

165 x 152 T

@20 kg/m S275

280 ASB 74

254 x 146 UKB31

S275

2 8 0 A S B

7 4

165 x 152 T

@20 kg/m S275

280 ASB 74with anchored re-barsor 203 UKC 46 + plate

2 8 0

A S B

7 4

2 8 0

A S B

7 4

o r 2 5 4

U K C 8 9

+ p

l a t e

6 7 0 0

= Decking propped at construction stage

P

P

P P

P

P

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C 7 1 S 3 5 5

2 0 3 U K C

7 1

S 3 5 5

2 0 3 U K C

7 1

S 3 5 5

2 0 3 U K C

7 1 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C 5 2 S 3 5 5

2 0 3 U K C

5 2 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

8 6 S 3 5 5

2 0 3 U K C

8 6 S 3 5 5

2 0 3 U K C 4 6 S 3 5 5

280 ASB 74

with anchored re-barsor 203 UKC 46 + plate

7500


280 ASB 74 or203 UKC 46 + plate


26/36

26

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

5400

280 ASB 100 280 ASB 74

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

7500

2 5 0 x 1 5 0 x 6

. 3 R H S

+ p l a t e S 3 5 5

7500 7500

300 x 200 x 8.0 RHS

+ plate S355300 x 200 x 8.0 RHS

+ plate S355

250 x 150 x 8.0 RHS

+ plate S355

5 0 0 0

2 8 0 A S B 7 4

2 5 4 x 1 4 6 U K B 3 1

S 2 7 5

2 8 0

A S B 7 4


Void

Stair Lift

C F 5 1

C F 5 1 C

F 5

1

300 x 200 x 8.0 RHS

+ plate S355

2 8 0 A S B 7 4

300 x 200 x 8.0 RHS

+ plate S355

2 8 0 A S B 7 4

2 8 0 A S B

7 4

C F 2 2 5

1 5 0 x

9 0 I

150 x 90 I

152 x 89 I

250 x 150 x 8.0 RHS+ plate S355

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

1 6 5 x 1 5 2 T

@ 2 0 k g / m

S 2 7 5

2 5 0 x 1 5 0 x 6

. 3 R H S

+ p l a t e S 3 5 5

2 5 0

x 1 5 0 x 6

. 3 R H S

+ p l a t e S 3 5 5

2 2 0 0

4 8 0 0

6 7 0 0

3 0 0 x 2 0 0

x 1 0 . 0 R H S S 3 5 5


3 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

3 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S

S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H

S S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

280 ASB 100

280 ASB 100280 ASB 100 280 ASB 74

3 0 0 x 2 0 0 x 1 0 . 0 R H S

S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 0 0 x 2 0 0

x 1 2 . 5 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 2 . 5 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

P P

Figure 3.13 Structural layout for deep plan building – RHS edge beams and

RHS columns as a wind moment frame option.



27/36

27

2 8 0 A S B

7 4

280 ASB 74

2 8 0 A S B

7 4

280 ASB 74 280 ASB 74

2 8 0 A S B

7 4

3 0 0 x 2 0 0 x 6 . 3

R H S

+ p

l a t e

250 x 150 x 10.0 RHS

+ plate

280 ASB 74

Stair

2 8 0 A S B

1 0 0

Riser

Lift

2 8 0 A S B

1 0 0

2700 2100

250 x 150 x 10.0 RHS+ plate

250 x 150 x 10.0 RHS+ plate


280 ASB 74

2 5 4 x 1 4 6 U K

B 3 1

S 2 7 5

2 5 4 x 1 4 6 U K B

3 1

S 2 7 5

254 x 146 UKB31S275

2 0 3

x 1 3 3 U K B 2 5

S 2 7 5

2 0 3 x 1 3 3

U K B 2 5

S 2 7 5

2 8 0 A S B

1 3 6

3 0 0 x 2 0 0 x 1 2 . 5

R H S

+ p

l a t e

4 8 0 0

1 9 0 0

1 0 0 0

2 3 0 0

2 0

0 0

3 9 0 0

7 2 0 0

1200 4800 1200

72006300 6300

1 5 0 x 1 5 0 x 6 . 3 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 1 0 . 0 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 2 . 5 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5

3 0 0 x 2 0 0 x 1 2 . 5 R H S S 3 5 5

250 x 150 x 10.0 RHS

+ plate

2 5 0 x 1 5 0 x 8 . 0 R H S S 3 5 5 250 x 150 x 10.0 RHS

+ plate

3 0 0 x 2 0 0 x 1 2 . 5 R H S

S 3 5 5

P

PP

2 5 0 x 1 5 0 x 8 . 0 R H S

S 3 5 5

1 5 0 x 1 5 0

x 6 . 3 R H S

S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5

2 0 0 x 2 0 0 x 1 0 . 0 R H S S 3 5 5


2 8 0 A S B 7 4

280 ASB 74

2 8 0 A S B 7 4

165 x 152T @20 kg/m S275

165 x 152T @20 kg/m S275

2 8 0 A S B 7 4

2 8 0 A S B

7 4 o r

2 5 4 U K C 7 3 + p

l a t e

1200 4800 1200

72006300 6300

4 8 0 0

280 ASB 74

Stair

2 8 0 A S B

1 0 0

Riser

2 8 0 A S B 1 0 0

2700 2100

Lift

300 deepslab onCF225

decking280 ASB 74

2 5 4 x 1 4 6 U K B 3 1

S 2 7 5

254 x 146 UKB31S275

2 5 4 x 1 4 6 U K B 3 1

S 2 7 5

2 0 3 x 1 3 3 U K B 2 5

S 2 7 5

2 0 3 x 1 3 3 U K B 2 5

S 2 7 5


2 8 0 A S B 1 3 6

2 0 3 U K C 8 6 S 3 5 5

2 8 0 A S B 1 0 0

o r 2 5 4 U K C + p l a t e

w i t h a n c h o r e d r e - b a r s

3 9 0 0

1 9 0 0

1 0 0 0

2 3 0 0

2 0 0 0

7 2 0 0


PP

2 0 3 U K C 4 6 S 3 5 5

2 0 3 U K C

8 6 S 3 5 5

2 0 3 U K C 8 6 S 3 5 5

2 0 3 U K C 4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C 8 6 S 3 5 5

2 0 3 U K C 4 6 S 3 5 5

2 0 3 U K C

4 6 S 3 5 5

2 0 3 U K C

5 2 S 3 5 5

2 0 3 U K C 4 6 S 3 5 5

2 0 3 U K C 4 6

S 3 5 5

1 5 2 U K C

3 0

S 3 5 5

1 5 2 U K C 3 0 S 3 5 5


280 ASB 74with anchored re-bars






P

Figure 3.15

Structural layout for shallow plan building – RHS edge beams and RHS columns

acting as wind moment frame.

Figure 3.14

Structural layout for shallow plan building – ASB edge beams and UKC columns.


28/36

28

203 UKC 86

Column

4 No. M 20bolts

300 x 300x 15 thk plate

4 No. M20g8.8 bolts

300 x 200 x 12 thk

ASB end plate

280 ASB 74edge beam

280 ASB 136

80 120

120

200

120

80

120

320 x 180x 12thk plate

Figure 3.16 ASB connection to edge column (showing eccentric detail).

120

31.5

80

4 No. M20g8.8 bolts

300 x 200 x 12 thk ASB end plate

280 ASB 74edge beam

120

203 UKC 86Column

280 ASB 136320 x 200

x 12thk plate

4 No. M 20bolts

80 120

140

Figure 3.17 ASB connection to edge column (no eccentricity).



29/36

29

320 x 200x 12thk plate

250 x 150 x 10 thk RHS column

4 No. M 20Hollo-bolts

280 ASB 136

170 x 430x 12 thk plate

M20 Hollo-boltsin 33 O/ holes

280 ASB 136

250 x 150 x 6.3 thk RHS Slimflor® beamand 15 mm thk plate

80 120

120

70

50

10010

40

(min.)

Figure 3.18 RHS edge beam connection to RHS column.

100

ASB

Tie beamcut from457 x 191 UKB

ASB

Tie beamcut from457 x 191 UKB

Facade line Facade line


(a) Column on centre-line of edge beam

(c) Plan on column in (a) (d) Plan on column in (b)

(c) Column along facade line

20050

200

100

50

50 50 100

50

200

360

300

20 mmdia. bolt

150

80

300

SHS column

Flowdrillbolt holes(20 mm dia.)

12

12

200

300

Seating platewelded betweenend plates

Seating platewelded betweenend plates

50

Figure 3.19 ASB bolted connections to RHS column.


30/36

30

Table 3.1 Summary of steel weights kg/m2 for various structural options.

A typical detail of a light steel separating wall

at a RHS column is illustrated in Figure 3.20.

The wall thickness is 300mm when using a200 x 200 RHS column. The wall thickness will

increase if larger columns are used.

Material usage

The typical steel usage for a six-storey building

(relative to the gross floor area) is:

● Beams 32-38kg/m2

● Columns 7-10kg/m2

● Bracing, secondary beams 1-3kg/m2

The precise values for the various structural

options are presented in Table 3.1. A steel

weight of 40-45kg/m2 may be used for scheme

design using Slimdek ®, increasing to 50kg/m2

for more complex building shapes.

The structural arrangement can be adapted to

any sensible plan form.

It is apparent that the weight increase in the

steel structure is negligible for this six-storey

building when designing using the ‘wind

moment’ principle. However, the connections

may be more complex.

The self-weight of the 300mm-deep composite

slab is 350kg/m2 in normal weight concrete,

which requires propping during construction

for spans in excess of 6m. However, the

self-weight is reduced to 280kg/m2 when

lightweight concrete is used, which does not

require propping for spans of up to 6.3m.

19 mm plank

12 mm fireresisting board

Mineral wool insulation

30 mm thick dense mineralwool board

200 x 200SHS column

100

100

38 300

Figure 3.20 Detail of separating wall at RHS column.


Beams Edge Columns Bracing

Beams

ASB ASB UKC Braced 33 7 1 41

Wind

ASB RHS RHS moment 35 8 – 43

frame

Braced -

ASB ASB UKC slab span 33 8 1 42

longitudunal

Braced -

ASB ASB UKC slab span 39 8 1 48

transverse

Wind

ASB ASB UKC moment 39 8 - 47

frame

Wind

ASB RHS RHS moment 38 9 - 47

frame

Structural weights (kg/m2)

Beams Columns Bracing

Building

Options

Shallow

Plan

Form

Deep

Plan

Form

Total

kg/m2


31/36

31

In the first case, no vertical load is transferred

to the structure or façade of the building, but

the modules are attached to the structure for

horizontal restraint. In the second case, the size

of the balcony is limited in order to reduce the

moments that are transferred to the internal

structure. In the third case, the ties can be

relatively unobtrusive but vertical ties willrequire a projecting structure such as a roof

truss, to carry the loads on all the balconies.

In conventional concrete construction, the slab

is continued outside the building envelope to

form a balcony or other projection. However,

this is no longer the preferred solution

because of the need to prevent ‘cold bridging’

through the slab, to meet the new Part L

Building Regulations. It is now necessary to

provide a ‘thermal break’ in the slab, or toinsulate it externally.

Types of balcony

Modern balconies are usually prefabricated

steel units, which are attached to the internal

structure by brackets or through posts, so that

‘thermal bridging’ effects can be minimised.

The three generic balcony systems are

detailed below:

1. Stacked ground-supported modules, which

may be installed as a group by lifting into

place. The columns extend to ground level.

2. Cantilever balconies, achieved by either:- Moment connections to brackets attached

to torsionally stiff edge beams.

- Moment connections to ‘wind-posts’

connected between adjacent floors.

3. Tied balconies achieved by either:

- Ties back to wind-posts or to the floor

above.

- Vertical ties to a supporting structure

located at roof level.

Figure 4.1 Steel balconies attached to curved edge beam in Slimdek ® at Harlequin Court, London (Goddard Manton Architects).

Steel balconies and parapets

Balconies and terraces are important additions to modern urban living,which often require interesting architectural solutions.


32/36

32

Balcony attachments in Slimdek®

In Slimdek®, RHS edge beams are torsionally

very stiff and are recommended for

cantilever attachments of balconies, where

brackets are welded to them. To minimise

‘cold bridging’, a single bracket at each side

of the balcony should be used.

Wind-posts may be bolted to the top and

bottom of ASB edge beams or to fin plates

welded to RHS edge beams. They are

designed to resist moments developed by

the cantilever balcony and can be relatively

large. Again, RHS sections may be

preferred. The attachment of balconies to acurved façade in Slimdek® is illustrated in

Figure 4.1.

50 200

Facade line

Slab level

Cut inedge trim

Bolted connection

a) Bracket connection to ASB b) Longitudinal view of bracket

Figure 4.2 Bracket attachment to ASB edge beam.


a) Pre-welded cantilevers b) Bracket or fin attachment

Figure 4.3 Cantilever or fin attachments to RHS edge beams.

Details of various forms of attachment of

balconies to RHS and ASB edge beams are

illustrated in Figure 4.2 and Figure 4.3. They

are designed to minimise ‘cold bridging’.

The support of a tied steel balcony to ASB

edge beams is illustrated in Figure 4.4. The

fin plate welded to the ASB provides a direct

attachment both for the balcony and for

the tie to the balcony below, and minimises

‘cold bridging’. Torsional effects are resisted

by the continuity effect of the slab, when

the deck ribs are orientated as in this figure.

When the deck ribs are orientated parallel

to the ASB, and it is merely acting as a

cladding support, torsional effects shouldbe tak

www.tatasteelconstruction.com static files staticfiles section plates publications sections...

Documents