Steel Insight 1a

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STRUCTURAL STEELWORK

STEEL inSighT #01


2/7

| OCTOBER 2011

Structural steelwork accounts for about 70% of multi-storey building frames built in the UK. Steel

Insight will appear quarterly to provide a source of reliable information for users of this key material

l inighuual lwk

01 | ntroduction

02 | he importance of realistic steel pricing

FI 1: MK F -MSI SUU FMS

For most projects, te decso

o te rme mter d orm

ppes ery te des

process, ote o te bss o

ery des prcpes, mted

ormto d bdet costs.

ce seected, te rme

mter s ey to ce,

s do so c ve sfct

prormme mpctos, sc

s coseqet mpct o te

des o oter mjor eemets,

cd cdd d M&

sttos.

we or most deveopmetste decso o rme type

ot be bsed o cost oe, t s

everteess ey cosderto

te decso m process

d t s vt to spport ormed

decso m t restc cost

ormto t ts ery ste,

beore ref dr te deted

des stes.

s s ce ts s tecost o strctr stee s bee

storcy vote d recoc

mter prce ormto t

retred teder prces s ot

ys strtorrd. tee

rme costs re so evy

ected by project-specfc ey

cost drvers, sc s prormme,

ccess, sps d bd orm,m ccrte djstmet o

recety tedered rtes or cost

modes dfct.

For tose t mted prevosexperece o stee-rmed

costrcto, te qe

crcterstcs o te sector my

ot be mmedtey ppret.

aecdot stores pot to des

decsos be mde o te bss

o o- or poory-djsted storc

stee rtes, sest tt te

compextes o te dstry

d te sfcce o ey cost

drvers re ot ecessry dey

derstood.

vere cross te st10 yers, stee rmes ve

ccoted or 70% o

o-domestc rmed

mt-storey uk costrcto

(see fre 1 bove) d 2010

strctr stee d 68% mret

sre o te edcto sector, 55%

o te et sector d 65% o

te ret sector. ese sttstcs d reve orecet dstry treds ts

te mportce o mt

crret, mret tested cost dvce

or strctr steeor.

ro cosderto o mber o ey ctors d

costto t te mret d

sppy c, bdet strctr

steeor estmt c be

qcy d sccessy tored

to specfc projects.

As the selection of frame

material is a key design decision

and impacts on so many related

building elements foundations,

nishes, wall-to-oor ratio and

cladding, to name but a few

once the decision has been made

and design has progressed it is

disruptive and generally abortive

to make fundamental changes

to the frame type or form. o

do so would involve going backover design stages already

completed and would involve

most of the design disciplines. Where there is a programme

to be maintained, this is almost

impossible to achieve. herefore,

although the period of time to

identify and select the best value

frame is not a long one, it should

not be rushed.

By its very nature therefore, thedecision is commonly based on

outline design proposals, with

a limited amount of information

available to the cost consultant.

Where the initial budgetestimates of steel frame costs

are not realistic, the wrong frame

solution can be selected at a

higher cost of not only the frame

but potentially also the related

building elements.

t can also have an effect onbuildability, logistics and theconstruction programme, as the

frame construction is a critical

path activity.

etting it wrong can resultin higher frame costs, higher

costs of associated elements,

longer programme and abortive

design work.

While it is clear that it isimportant to maximise the

accuracy of early estimates of

frame costs, there are a number

80%

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60%

50%

40%

30%

20%

10%

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3/7

h | OCTOBER 2011

rends in price cn oten

be better nderstood whenconsidered longside trends

in otpt nd spply nd

this is no dierent or

strctrl steelwor.

along with the whole o

the constrction indstry, the

economic recession hs hd

signifcnt impct on the uk

steel indstry.

as steel is reqired erly in the

constrction process, the eects

o the recession were elt in the

steel sector qicly ter thecrisis hit.

a signifcnt nd shrp ll in

otpt o lmost 32% occrred

between 2008 nd 2009, with

contining decline bt t mch

lower rte dring 2010.

he British onstrctionl

teelwor assocition (Ba)

orecsts tht otpt will

hve remined irly constnt

cross 2011, with erly orecsts

sggesting totl o rond

940,000 tonnes; this is, howevestill some 30% less thn the pe

o ctivity in 2008.

Forecsts or 2012 nd 2013

re more optimistic nd the

Ba orecsts increses

o 4% throghot 2012 nd

5% throghot 2013, which

i relised wold see otpt

recovering to over 1 million

tonnes per nnm by the end

o 2013.

03 | Recent output trends

o difculties acing cost

consultants trying to do so.

As fgure 2 (overlea) sows,

tere as been signifcant

istoric volatility in structural

steelwork material prices. is

makes cost models, bencmarks

and previous project data

difcult to adjust accurately and

te use o indices not as useul a

tool as or some oter materials.

imilarly, te cost o structuralsteelwork can vary signifcantly

between projects, wic at frst

glance appear broadly similar.

Project specifc actors must be

considered in order to produce a

project specifc cost.

t as also been istorically

difcult to get valuable input

rom te marketplace during te

early design stages, reducing te

extent to wic current market

conditions can be assessed.


4/7

| OCTOBER 2011

04 | Recent cost trends

Fgure 2 plot the Department for Bune,

innovaton and skll (B s) materal prce

ndce for fabrcated tructural teelwork,

concre e re n orc ng ar, cemen , concre e an

precat concrete nce March 2008, when the

ndex wa re-baed. llutrate the volatlty

n both tructural teel and teel renforcement

materal prce over the lat three-and-a-half

.

arly 2008 aw teep re n the prce of

fabrcated tructural teelwork and renforcng

bar a the level of actvty and demand for

teel product reached t peak.

wa o owe y arp an g n can

reducton n teel prce n the econd half of

2008 nto 2009. the market truggled to

adapt to the reducton n demand, there wa a

perod of overcapacty and overupply n the

mar e , r v ng prce own.

hroughout 2009 the prce of fabrcated

teelwork contnued to fall before tablng

at a low pont toward the end of the

year, a upp er ene e rom a ng

commo y pr ce an ower a our co , an

mplemented maller margn to ecure the

reduced quantty of work.

in lne wth the 32% fall n output acro

an , ra e or a r ca e ee wor

had alo fallen by almot 35% by early 2010.

owever, 2010 aw change n the market

or a r ca e ee wor . e e ou pu o

he ndutry may have contnued to fall, rng

commodty prce and prce re ntroduced

by uppler, uch a the 50/tn re n March

2010, put preure on the ndutry and

reu e n ome recovery n ma era prce.

he rt half of 2011 aw fur ther ncreae n

teel materal prce, wth concrete renforcng

bar prce ncreang by 8% between January

and June. owever, the mot recent data from

une an u y ow a g ec ne n

materal prce, a the ntal optmm n early

gn of economc recovery from the tart of

he year have largely faled to materale.

he Bis data clearly how volatlty n

ruc ura ee ma era pr ce over e a

hree year and perod of ncreae over

he lat 18 month. owever, an analy

of returned tender prce for teel-framed

buldng over the ame perod how that

a er an n a a n en er ra e or ruc ura

teel n 2008 and 2009, the ubequent

ncreae n materal prce have been

aborbed by the upply chan n the face of

contnung weak demand n the contructon

ec or an a par o en er pr c ng ra eg e.

At the early design stages of any project,

cost models, benchmarks and historic

cost data are key tools used by cost

consultants in the estimating of all

u ng e ements.

At this stage elemental costs, including

those of the structural frame, will usually

be expressed as a rate per m2 based on

the ross nternal Floor Area (FA).

ypical cost ranges for different frame

types can e eve ope t roug cost

models and there are some indicative

ranges given as part of this article but

how should you pitch the rate for any

given project?

at er t an ar trar y us ng t e g est

rate of a range, it is key to interrogate andunderstand what those rates buy and how

the standard ranges can be adapted to

suit project-specic factors.

o o t s most accurate y, t e

cost consultant needs to ask relevant

questions of the design team and to speak

to the supply chain to use this information

effectively. his will build a picture of the

current and short-term future market,

rather than relying on indices to adjust

benchmark or historic rates.

05 | Ma ng t e most o

ava a e n ormat on

owever, the forecat ncreae n tructura

teelwork output over 2012 and 2013 and

contnued materal prce re mut be

mon ore care u y a ey o ugge a

an ncreae n tructural teelwork tender

prce could be een acro 2012, epecally n

locaton where recovery wll be een rt.

he volatlty of materal prce ndce

compare w e curren re a ve a y

of returned tender prce alo hghlght the

danger of relyng on materal prce trend

to adjut htorc data to produce accurate

forecat for future development.

e a conc u on a cou e rawn

from th unpredctablty that t almot

mpoble for the cot conultant to prce

tructural teelwork realtcally, relyng on

ther uual cot databae. hat t hould do

encourage oe o ng e co ng o pea

to the upply chan to get a pcture of current

trend from thoe workng wth and buyng

teel on a day-to-day ba.

FIg 2: departMent For BUSIneSS, InnovatIon and SKIllS data

200

175

150

125

100

75

Mar 08 ep 08 Mar 09 ep 09 Mar 10 ep 10 Mar 11

oncrete

renforcng bar

Fabrcated

tructural teel

ement

oncrete

Precat concrete


5/7

h | OCTOBER 2011

nallaon o, olerane and nerfae.

. ocation, logistics and access

he loaon of a proje a key faor n

pre deermnaon and nde are avalable

o enable he adjumen of o daa aro

eren reg on.

nde urrenly how he y of

ondon a 119, Manheer a 97, cardff a

93, lagow a 103 and Belfa a 64 (gure

4); hee varane hghlgh he exene

o eren mar e on on n eren

regon, whh mu no be overlooked.

o only he geograph loaon of he

e an mporan onderaon, e-pe

feaure alo need o be revewed.

e e e g ne rame o u on o wo

buldng may be very mlar, he log and

ae arrangemen wll vary gnanly

beween a ongeed y enre e and

an ealy aeble, olaed bune park

or n u r a e a e e, or even e ween

alernave y enre e.

orkng n y enre or ouped area

an mean reron o workng hour, noe,

e ver e an raneage, a o w n uene

n a a on o an an reu n an ex en e

on- e programme. he frame onruon generally

a ral pah avy, any nreae o

e on ru on programme w ave an

ao a e mpa on pro e o .

. Programme, risk and procurement route

the rae gven n h arle an be

on ere u a e or e o p a nn n g o

pro e w ere e ru ura wor wou

ommene n he nal quarer of 2011 or he

r quarer of 2012.

Beyond h meframe, aurae

06 | Key cost drivers

number of faor an be ondered o

have a key mpa on he pre of ruural

eel frame.

1. Function, sector and building eigt

Dfferen buldng funon aro dfferen

eor have varyng ypal frame o due

o dfferen uage of he reaed oor pae.

e uage o e u ng w n uene e

degn loadng ondered by he ruural

engneer and he buldng funon wll alo

reul n dfferen requremen for lear pan

and oor-o-oor hegh. th mean ha

e average we g o e ee rame w vary

beween buldng ype. For example, a low

eave ndural hed buldng ould have a

frame wegh of 40kg/m2 iF, whle a y

enre ofe wh a long pannng grd o

avo a ore o o umn , ou ave a we g

of 90kg m2 .

Fewer olumn wll lead o longer pannng

beam and heaver eel eon, whh an

nreae he overall wegh of he frame and

ere ore e o range or e u ng.

learly, hee faor need o be ondered

when deermnng he rae for he ruural

frame for early emae. conrmaon of he

degn aumpon and prnple wh he

ru ura eng neer een a o ar y .

alo mporan o remember ha he

ra e per m2 baed on gro nernal oor

area, whh wll no aoun for varane n

oor-o-oor hegh.

, o r a pe pro e , ee are ou e

he normal range uled n o model, a

hgher or lower rae hould be ondered o

alor ndave rae o he proje.

. orm, s te con t ons an comp ex ty

he omplexy of he ruure loely

relaed o buldng form and funon, a well

a pe e ondon.

the buldng form wll have an mpa on he

regu a r y o e ru ura gr an e nee

o nrodue non-andard eon, a wderange of dfferen eon and onneon n

order o aheve ruural ably.

complex ruural oluon, uh a

ran er ru ure an ma e-up eam may

alo need o be nrodued o overome

proje-pe feaure or reron uh a

reaned faade, adjaeny of oher buldng,

ground ondon and o on.

e n u o n o non- an ar e on

wll alo nreae he overall frame rae a

fabraon o are hgher and omplex

onneon deal may alo mpa on

orea o ee rame o are

u ue o e uner a n y o genera

eonom ondon and he hor

volaly of maeral pre experened n

he eel ndury.

ne ea ure o e eonom ree on a

been an nreae n he relave prevalene o

ngle-age prouremen roue, parularl

degn and buld, ompared wh he

prevouly domnan wo-age approah.

a a gne ma n on ra or e e on

an pr e e a men more oe y an a

nreaed he empha on marke prng

raegy where, whle rk may be dened

hey may no be pred n o ender reurn

a o a een ur er reng ene a e

major deermnan of onraor eleon.

here were nal gn of mprovemen

n he nanal erve eor n early

2011 and opmm ha he ommeral

e or may egn o ee re urne eman .

hee have o far largely faled o

maerale and he eonom oulook

reman hangeable.

ven wh forea of maeral pre

on nung o r e over an , e

relavely low poon of demand n relaon

o apay n he ruural eelwork ndu and onnued nene ompeon n

he onruon ndury generally

mean a on ra or pr ng ra eg e

wll reman an mporan feaure n eurng

work. h expeed o a a a downward

preure on pre.

ardner & theobald nal quarer 2011

en er r e n e orea an overa

delne n average ender pre aro

2011, wh a 0.5% re forea aro 2012

and 2% re aro 2013, adjued down from

earler forea.


6/7

| OCTOBER 2011

07 | Current costs

his rticle seeks to give some current

indictive cost rnges for structurl steel

frmes for three key building types:

1. ow rise and short span buildings,

typically two to four storeys

2. igh rise and longer span buildings,

typically 10-15 storeys plus basement

3. ndustrial buildings, split into low eaves of

6-8m and high eaves of 10-13m

all of the costs include llownces for

concrete core. he rtes hve been developed

from cost models of the different building

types nd for ech the verge weight of the

structurl frme hs been given.

as lredy highlighted, before using such

stndrd rnges it is importnt to conrm

the nticipted frme weight nd vribles

such s the oor-to-oor heights with the

design tem, to determine whether they re

bove or below the verge nd to djust the

rte used ccordingly.

imilrly, ll of the other key cost drivers of

complexity, site conditions, loction, function,

logistics, progrmme nd procurement

strtegy should be considered in turn.

1. ow rise and short span buildings

ow rise buildings with regulr, short spn

structurl grid re typicl fetures of business

prk ofces nd teching fcilities.

a key feture of these buildings is exibility,prticulrly for specultive business prk

developments tht need to ppel to s mny

potentil occupiers s possible.

he buildings often need to be esily

subdivided into smller units nd hve

lrge oorpltes. ypiclly they re two to

four storeys, with oor-to-oor heights

of 3.75-4m.

hey will typiclly hve uniform grid of

6-9m tht provides lrgely column-free spce

nd reltively high oor-to-oor heights.

he lck of complex steel structures neededto construct the regulr grid contributes to

keeping the verge steel frme weight down

(typiclly 50-60kg/m2 including ttings)

but this ctegory cn cover lot of building

types nd functions. his centrl ssumption

therefore needs to be reviewed with the

design tem.

Due to the low rise nture of these buildings,

the re protection requirements re not s

onerous s for high rise developments nd

30-60 minute re protection would be

considered stndrd.

2. igh rise and longer span buildings

igh rise construction (10-15 storeys) is

typicl feture of city centre construction.

hese buildings will often require longer

structurl grid spns to chieve more open

spce in the lettble oor res, incresing the

weight of the steel frme.

o mximise oor-to-ceiling heights, nd

increse exibility for the building t-out,

cellulr bems my be dopted with openings

through the web for the distribution of

services.

ity centre buildings re generlly

constructed on existing conned or irregulr

sites, which inuence the building form. his

is likely to prevent the use of regulr column

grid nd my result in ltertions to oor pltes

on the upper storeys.

n mixed-use schemes, trnsfer structures

my reduce the wider grids of ofce or retil

res t lower levels to more rtionlised

residentil grid on upper oors.

all of these fctors contribute to higher

verge weight of the steel frme, typiclly

65-85kg/m2 including ttings nd, long with

the incresed complexity, result in signicntly

higher structurl frme rnges thn for the

simpler, more regulr low rise buildings.

he rte rnge given in gure 3 is generlly

pplicble for buildings up to bout 15 storeys;

tll buildings bove 15 storeys strt to hve

fewer comprbles in terms of benchmrks

nd re likely to hve much higher

proportion of complex elements, non-stndrd

sections nd complicted logistics, especilly

when constructed on tight city centre sites.

he rte rnge for tll buildings cn be 15-20%

higher thn the top of the stndrd rnge.

3. ndustrial buildings

ndustril buildings cn cover rnge of uses,

including wrehouses, non-food retil, science

FIgUre 3: IndIcatIve coSt rangeS BaSed on groSS Internal Floor area

ocation BC ndex ocation BC ndex

ity of ondon 119 eeds 97

ottinghm 94 ewcstle 94

Birminghm 97 lsgow 103

Mnchester 97 Belfst 64

iverpool 93 rdiff 93

FIgUre 4: BcIS locatIon FactorS, aS at 7 oct 2011

P

Frame - low rise, short spans, repetitive

grid / sections, easy access

Frame - high rise, long spans, irregular

grid or sections, complex access

Floor - metal decking and lightweight

concrete topping

Floor precast concrete composite

oor and topping

Fire protection (60 min resistance)

Portal frames low eaves (6-8m)

Portal frames high eaves (10-13m)

FA Rate ()

BC ndex 100

75 - 100/m2

140 - 165/m2

50 - 65/m2

55 - 70/m2

6 12.50/m2

45 - 65/m2

55 - 75/m2

FA Rate ()

City of ondon

90 - 120/m2

165 - 195/m2

60 - 75/m2

65 - 80/m2

7 - 15/m2

55 - 75/m2

65 - 90/m2


7/7

g | OCTOBER 2011

08 | he cost table

09 | ummary

he selecton of structural frame materal

and form s a key early decson n the

desgn process. it should be regarded as an

opportunty to maxmse value by ensurng

that the selecton s based on project-spec

costngs and avodng unnecessary mpacts

related elements or overall programme.

he challenge to the cost consultant s to

recognse and overcome the hstorc volatlt

n materal prces n relaton to returned tend

prce data, all n the context of lmted desgn

nformaton durng early estmates.

hs artcle has outlned a number of key

cost drvers that must be consdered n orde

to make steel frame rates project specc.

ommuncaton th the desgn team to

clarfy the steel frame eght, potental for

complex sectons and requred re protecto

desgn assumptons are all essental.

Fnally, consultaton th the supply chan

ll enable current nformaton on order boo

and materal prces to be consdered.

hrough the dentcaton of the key facto

relevant to each project and the adjustment

of typcal rates accordngly, the accuracy of

budget structural steelork estmatng can b

sgncantly mproved.

his article was produced by Rachel

Oldham (associate) and Chris Welch

(partner) of gardiner & heobald. t is the

rst in a series that will provide uidance

on the accurate costin of structural

steelwork. he next teel nsiht will

appear on 27 January 2012. f you are

considerin usin structural steelwork

for your buildin, bride or structure,we recommend an early dialoue with

a specialist steelwork contractor. hey

can offer a rane of support and advice,

includin budet estimates and value

enineerin. teelwork contractors can

be sourced accordin to project size and

technical competency. his searchable

function is available at

the Steel InSIght SerIeS

WWW.CORCO.ORg

parks and dstrbuton centres.

he most common buldng form s a sngle

storey arehouse th varyng proportons of

ofce space on a rst oor mezzanne level.

he tradtonal structural frame for an

ndustral buldng s a steel portal frame, as

exblty of the nternal space s a prorty,

necesstatng regular column spacngs and

long spans for a clear nternal area.

here can be varants on the standard frame

desgn, hoever. For example, a steel portal

frame ncorporatng northlghts ould need

consderaton hen adjustng the standard

cost ranges. he use of a northlght frame can

ncrease the frame cost by as much as 30%.

Fre protecton requrements must also

be consdered as part of ndustral buldng

frame costs. ommonly, re protecton s

only requred n sngle storey buldngs to

satsfy boundary condtons and ths s a

project-specc factor that ll need some

lason th the desgn team.

nother key factor n determnng the frame

cost of ndustral buldngs s the storey heght

of the arehouse space. whle the gross

nternal oor area may be the same, the eght

of the steel frame of a hgh eaves, sngle storey

ndustral buldng ll be hgher than for a lo

eaves buldng, resultng n a hgher overall

frame cost per m2 iF.

ypcal structural steel frame eghts for

lo eaves buldngs (6-8m hgh) are about 30-

40kg/m2 overall of iF, ncludng ttngs, and

about 40-50kg/m2 for hgh eaves buldngs

(10-13m hgh). oever, ranges for hgh

eaves buldngs are generally der than for

lo eaves buldngs as they can have a much

hgher proporton of upper oor areas, across

as many as three mezzanne levels; the frame

rates for these buldngs therefore need to be

looked at carefully on an ndvdual bass.

he cost table included as ure 3summarises the structural frame costs of the

three buildin types and a lso provides some

indicative cost information on oor types

and re protection.

While precast concrete products have not

seen the material price volatility experienced

by structural steel durin the economic

recession, it is worth notin that the sector

has experienced chane. Fewer rms are

now involved in the supply of precast units,

so timin of particular projects can have a

sinicant impact on the rate. his is another

sector where it is very important to liaise

with the supply chain as soon as possible to

et real market feedback.

he indicative rane iven for re

resistance is suitable for buildins with a

predominant requirement for 60-minute re

resistance. Buildins with a predominant

requirement for 90-minute re resistance or

hiher will be outside of this rane.

o use the table, rst identify which frame

type most closely relates to the project

under consideration, then select and add the

oor type under consideration. Finally, add

re protection if required.

For example, usin the BC ndex 100

rates for a low rise, short span framed

buildin with a composite metal deck oor

and 60 minutes re resistance, the overall

frame rate (based on the averae for each

rane) would be 87.50 + 57.50 + 9.25 =

154.25 per m2 ross internal oor area. For

a buildin in ottinham the rate would be

154.25 x 0.94 = 145/m2 gFA.he costs are presented in two columns:

one for the BC ndex 100 and one for the

City of ondon. For other locations, rates

should be adjusted usin location indices;

ure 4 contains a selection of indices as

published and updated by the BC.

he rates can also be considered suitable

for cost plannin of projects where the

structural works would commence in the

nal quarter of 2011 and the rst quarter

of 2012. After this point, a consideration of

ination should be made.

Documents

Steel Insight 1a