richard vincent_s16-2009.pdf

7/25/2019 Richard Vincent_S16-2009.pdf

http://slidepdf.com/reader/full/richard-vincents16-2009pdf 1/143

S16 -2009

What’s New?

The Steel Workshop

S16-2009: What’s New?

byRichard B. VincentCanam Group Inc.

Chairman of CSA S16 Committee



S16 -2009

What’s New?

Goal of the presentation:

• Review what’s new &

• Review what’s changed

in the 2009 Edition of S16.



S16 -2009

What’s New?

S16 presentation format:

• General change from a sentence with a list of items orrequirements to an enumerated list format.

• Done to make each requirement more visible.



S16 -2009

What’s New?

1: Scope and application

• Scope:

• States that design is an inextricable part of thedesign-fabrication-erection sequence.

• Design cannot be considered in isolation.

e.g.P-, P-, tolerances, bolt types and installation.

• Provides via “Annex A” a link to the “CISC Code ofStandard Practice.



S16 -2009

What’s New?

1.

• Scope:

Unless there is a specific CSA design standard, S16 is to be

used unconditionally for structural steel design.

However, supplemental requirements may be needed.

e.g.: loads may be unique, platework structures, cranerunway girder design

S16 is to Canada as AISC’s specification is to U.S.A.




S16 -2009

What’s New?

• Inspector a qualified person who acts for and on behalf of the

owner or designer on all inspection and quality matterswithin the scope of the contract documents.

Protected zones areas of members in a seismic force resisting system that

undergo large inelastic strains and in which limitationsapply to fabrication and attachments. arc-spot welds of deck are permitted to be attached deck to

beam flange

applicable to six of the seismic LLRS in Clause 27.




S16 -2009

What’s New?

• Segmented membera member with a constant cross-section when axial loadsare applied between in-plane lateral supports or frameconnections, and a member with cross-section changesbetween in-plane lateral supports or frame connections.

Seismic design storey driftthe storey drift obtained from the lateral deflectionsobtained from a linear elastic analysis multipliedby R dR o /IE.




S16 -2009

What’s New?

• Symbols

Generally all symbols are listed in Clause 2.2

Minor exceptions are when a symbol is used only once andis defined where it is used.

Reference Standards Steels - ASTM A 572 Galvanizing CSA G164 Metalizing - CSA G189 Steel Castings - ASTM A 216, ASTM A 352, and ASTM A 958 Bolting -ASTM F 2280 Anchor rods - CSA G40.21 or ASTM F 1554

2: Definitions and symbols



S16 -2009

What’s New?

• Drawings Need to show protected zones on structural design

documents

Shop details also need to show protected zones

Building Information Modeling (BIM) More often seen in large industrial projects

CISC Code of Standard Practice now has an appendix

dealing with subject.

4: Structural documents



S16 -2009

What’s New?

Material Selection - Rolled shapes

W-shapes - none currently rolled in Canada.

ASTM A572 grade 50 generally meets CSA G40.21 grade350W (Fy = 345 MPa vs. 350 MPa).

ASTM A992 - newer and tighter specification derived from ASTM A572 grade 50 (e.g. Fy /Fu controlled) - must bespecified for ductile seismic elements

ASTM A992 becoming basic steel grade. Can be purchasedwith Charpy V-notch testing to ASTM standards

5: Material – Standards and identification



S16 -2009

What’s New?

Material Selection - HSS

ASTM A500 Grade C – commonly available grade in Canada

ASTM A500 Grade B has been USA basic grade and it is notsame as Grade C nor Grade A.

Round HSS in ASTM A500 have lower Fy than squares andrectangular tubes

CSA G40.21 – 350W Class H can be made at Harrow plant of Atlas Tube




S16 -2009

What’s New?

Material Selection - HSS

Work underway at ASTM to produce new ASTM HSS

specification that would address many current issues,such as thickness tolerance, chemistry, but notnecessarily that of the corner radius.

This may still take a few years to complete.




S16 -2009

What’s New?

Material Selection - WWF, Plate

WWF is a Canadian product

Plate is rolled in Canada (and around the world)Wide variety of grades but CSA G40.21 350W and AT cat. 3commonly rolled at Essar Algoma

Bolts

ASTM A325 - ¾” diameter common for most applications ASTM A490 – less common.

ASTM F1852 (twist-off style for A325 applications) - morecommonly used as electric gun is quiet and faster toinstall




S16 -2009

What’s New?

Several new requirements have been added

1: Clause 6.7Requirements under fire conditions & refers users to Annex K.This is a mandatory Annex.

2: Clause 6.8Refers users to Annex L for guidance on assessment ofthe risk of brittle fracture.

This is an informative Annex.

6: Design requirements



S16 -2009

What’s New?

• For specified loads and importance factors for snow, wind &earthquake loads, the user is directed to Article 4.1.2.1 ofthe NBCC.

For factored loads, the user is again directed to NBCC for loadfactors, , for load combination cases in accordancewith Division B, Article 4.1.3.2.




S16 -2009

What’s New?

Wind loads:

One change of note that has occurred in the NBCC is theremoval of exposure C from the wind load commentary.

So, those designing buildings in dense urban environments willnow require exposure B and thus be designed for a higher windload effect.




S16 -2009

What’s New?

Flexural Strength

Maximum bending strength when member is “fully” laterally

supportedClass 1 and 2: Mr = Mp

NEW -singly symmetric I-sections and T-sections are not

permitted to yield under service load

Class 3: Mr = My

Class 4: Mr = SeFy

& b/t replaced with bel /t

13.5 Bending – Laterally supported members



S16 -2009

What’s New?

Laterally Unsupported Beams

Mu

for an un-braced length

NEW equation for 2

13.6 Bending – Laterally unsupported members

w y yu C I

L

E GJ EI

L

M

2

2



S16 -2009

What’s New?

Mmax = maximum factored bending moment magnitude

in unbraced segment

Ma = factored bending moment at one-quarter point of

unbraced segment

Mb = factored bending moment at mid-point ofunbraced segment

Mc = factored bending moment at three-quarter pointof unbraced segment

5.2474

4

2222max

max

2

cba M M M M

M



S16 -2009

What’s New?

Position of the load with respect to the shear centre

For unbraced beam segments loaded above the shear centrebetween brace points, where the method of load deliveryto the member provides neither lateral nor rotational restraint to

the member, the associated destabilizing effect shall betaken into account using a rational method.

For loads applied at the level of the top flange, in lieu of a moreaccurate analysis, Mu may be determined using 2 = 1.0 andusing an effective length, for pinned-ended beams, equal to1.2L and, for all other cases, 1.4L.



S16 -2009

What’s New?

Previous editions referred user to a rational method such as theone given in the SSRC’s “Guide to Stability Design Criteria for

Metal Structures”.

This edition gives users methods to determine resistances.

Sections covered:TeesI sections with unequal flanges (crane girders) Any section with a single axis of symmetry

13.6 (e) Flexure of monosymmetric sections



S16 -2009

What’s New?

Need to check:

Lateral-torsional buckling strength for each flange at any pointunder compression along unbraced length.

Yielding does not occur under service loads (more likely with

closely spaced braces)

Resistance expression used depends on relative values of M, Myr

and Mu




S16 -2009

What’s New?

Mu > Myr

Basic expression

whereMyr = 0.75 SxFy

and Sx is lesser of two possible values


p

u yr

u yr p pr M

L L

L L M M M M



S16 -2009

What’s New?

Mu Myr Mr = Mu

where

x = asymmetry parameter for singly symmetric beams

Expressions for x - Cw - 3 etc are given in S16.


y

w

y

x x

y

u I

C

EI

GJL

L

EI M 2

2

22

2

3

42



S16 -2009

What’s New?

Shear resistance:

Clause 13.4 reorganized

No technical change but users fell the new layout favoured theusual cases (unstiffened beams and girders) over theless frequent case (stiffened beams and girders)

13.4 Shear



S16 -2009

What’s New?

13.4.1.1 Elastic analysis

Vr = A wFs

where

A w = shear area

(dw for rolled shapes and hw for girders, 2ht forrectangular HSS)

and Fs is as follows:

(a) for unstiffened webs(b) for stiffened webs

13.4 Shear



S16 -2009

What’s New?

A couple of changes of which you need be aware.

Two main issues are:1. Format of ultimate tensile resistance

2. When Block Shear failure mode is present

Ultimate Tensile Resistance:

Tradition expressions: Tr = 0.85 A nFu

or Tr = 0.85 A neFu

Where here difference was either A n or A ne

and was taken as 0.90

13.2 Tension & 13.11 Block Shear



S16 -2009

What’s New?

Ultimate Tensile Resistance:

Retained second expression but modified to

Tr = u A neFu

where u is taken as 0.75

(basically 0.9 of 0.85 as before)

However you must satisfy that expression as well as the BlockShear requirements given in Clause 13.11.

13.2 Tension & 13.11 Block Shear



S16 -2009

What’s New?

Defined in Clause 12

For bolted segments inclined to the force between openings

(e.g., bolt holes) does not apply to area parallel to the force

When a tension load is transmitted by welds, add up to threenet areas, A n1, A n2 , and A n3 , but now it is clear that you can’t

exceed gross area, A g

Otherwise, no technical changes in Clause 12

12 Gross and net areas



S16 -2009

What’s New?

Block shear

Applies to tension members, beams, and plate connections.

The factored resistance for a potential failure involving thesimultaneous development of tensile and shear componentareas.

Revised substantially based on better and more information –University of Alberta tests and analyses.

13.11 Block shear



S16 -2009

What’s New?

Block shear

New expression and a table replace what was in previous

edition.

Expression is now

where Ut is an efficiency factor & given in accompanying table

13.11 Block shear

2)(6.0 u y

gvunt ur F F AF AU T



S16 -2009

What’s New?

Block shear

Ut = 1.0 is used for symmetrical blocks or failure patterns andconcentric loading

If Fy > 485 MPa, then use Fy in place of the term (Fy + Fu)/2

Connection type Ut

Flange-connected T’s 1.0

Angles connected by one leg and 0.6

stem-connected Ts

Coped beams

One bolt line 0.9

Two bolt lines 0.3

13.11 Block shear 10

13 11 Bl k h



S16 -2009

What’s New?

Block shear

What to do if one or two bolts in a line to prevent breakout

toward edge of plate?

Can use this term to determine breakout resistance

13.11 Block shear

2

)(6.0

u y

gvunt ur

F F AF AU T

= 0

13 3 A i l i



S16 -2009

What’s New?

Compression Members

Overview

Modified determination of

Added clauses for single angles used in

Individual members and planar trussesBox or space trusses

Added more for members that exceed width-to-thicknessratios (used to be called Class 4)

13.3 Axial compression

13 3 A i l i



S16 -2009

What’s New?


Allows use of consistent compressive resistance

expression for all cases covered.

Basic expression remains


nn

yr AF C /12 )1(

13 3 A i l i



S16 -2009

What’s New?


&

For usual cases this becomes


e

y

F

F

2

2

r

KL

E F e

E

F

r

KL y

2

13 3 2 Flexural torsional or flexural torsional buckling



S16 -2009

What’s New?

Only change is that following note has been added forclarification

“For equal-leg double angles connected back-to-back to acommon gusset plate, flexural-torsional buckling is not acontrolling limit state.”

13.3.2 Flexural, torsional, or flexural-torsional buckling

13 3 3 Single angle members in compression



S16 -2009

What’s New?

Four sub-clauses:

1. General – single angles neglecting the effects ofeccentricities, under certain conditions

2. KL/r for certain individual angles and angles of planar trusses.

3. KL/r for angles of box and space trusses

4. Others - e.g. differing end conditions, transversely loaded

13.3.3 Single-angle members in compression

13 3 3 1 General



S16 -2009

What’s New?

General - single angles, with conditions, neglectingeccentricities.

Slenderness to be used is defined as long as

1 - loaded at the ends through the same one leg2 - attached by welding or by minimum two-bolt

connections3 - no intermediate transverse loads

Where n = 1.34

13.3.3.1 General

nn

yr AF C /12 )1(

e

y

F

F 2

2

r

KL

E F

e

13 3 3 2 Individual members and planar trusses



S16 -2009

What’s New?

To determine KL/r for:

1 - Individual angles with leg length ratio < 1.7 and

connected through longer leg.

2 - Angles of a planar truss with adjacent web membersconnected to same sideweb members connected

to same side of chord or gusset.

0 L/rx 80: KL/r = 72 + 0.75 L/rx

L/rx > 80: KL/r = 32 + 1.25 L/rx 200

13.3.3.2 Individual members and planar trusses

13 3 3 2 Individual members and planar trusses



S16 -2009

What’s New?

Modifications to KL/r :

When leg length ratio < 1.7 and is connected through shorterleg,

then KL/r is

bl = longer leg of angle

bs = shorter leg of angler’ y = radius of gyration of single-angle member about minor

principal axis

13.3.3.2 Individual members and planar trusses

'2 /95.01)/(4 ysl r Lbbr KL

13 3 3 3 Box and space trusses



S16 -2009

What’s New?

To determine KL/r for

1 - Angles with leg length ratio < 1.7 and connectedthrough longer leg.

2 - With adjacent web members connected to same sideof chord or gusset.

0 L/rx 75: KL/r = 60 + 0.80 L/rx

L/rx > 75: KL/r = 45 + L/rx 200

13.3.3.3 Box and space trusses

13 3 3 3 Box and space trusses



S16 -2009

What’s New?

Modifications to KL/r :

When leg length ratio < 1.7 and is connected through shorterleg,

then KL/r is

bl = longer leg of angle

bs = shorter leg of angler’ y = radius of gyration of single-angle member about minor

principal axis

'2 /82.01)/(6 ysl r Lbbr KL

13.3.3.3 Box and space trusses

13 3 3 4 Other members



S16 -2009

What’s New?

When

1 - Angles with leg length ratio > 1.7 or

2 - Adjacent web members connected to opposite side ofchord or gusset, or

3 - Subjected to transverse loads.

Use Clause 13.3.2 accounting for eccentricities.

13.3.3.4 Other members

13 3 4 Segmented members in compression



S16 -2009

What’s New?

Handled in a new Clause 13.3.4

Rational method

Notional loads need not be applied between in-planelateral supports.

13.3.4 Segmented members in compression

13.3.5 Members in compression subjected to elastic



S16 -2009

What’s New?

This is for members we used to call Class 4 and still have twooptions

1 - Use effective area based on reducing elements

2 -Use effective yield stress which will make section meetslenderness limits

p jlocal buckling

13.3.5 Members in compression subjected to elastic



S16 -2009

What’s New?

Effective Area Approach

Effective Yield Stress Approach

p jlocal buckling

nn

yr AF C /12

)1(

e

y

F

F

nn

ye yer AF C /12 )1(

e

ye

F

F

25 Column bases and anchor rods



S16 -2009

What’s New?

New Clause 25.2:Now need at least four anchor rods.

When not feasible, take special precautions.

Anchor Rods:

New ASTM specification as well as G40 20/G40.21

F1554 - Standard Specification for Anchor Bolts, Steel,36, 55, and 105-ksiYield Strength

In computing the tensile resistance now A

n

= the tensile area of the rods = 0.85 A g

This replaces the two expressions for Imperial rods & metric rods based on number of threads or the pitch





S16 -2009

What’s New?

Bearing on concrete:

increased to 0.65 from 0.60 to match CSA A23.3

15 Trusses



S16 -2009

What’s New?

Analysis Methods1 - Simple

Removed the restraint for the relative resistancefor out-of-plane > in-plane for use of the simplifiedmethod

2 - DetailedRemoved trusses with bottom chord bearing from

obligatory detailed method

Splices

Splices may occur at any point in a chord or webmember (Clauses 15.2.4 and 15.2.5)

16 Open-web steel joists



S16 -2009

What’s New?

16.5.1 Loading for open-web steel joistsNew requirement under companion action loading

(d) for roof joists, 100% of the snow load plus 40% of

the downward wind load (companion load)

16.5.2 Design assumptionsThe resistance of the deck connections as well as the resistance

of the deck shall be verified by the joist designer to ensurethat adequate lateral support is provided to the top chord of a joist as determined in accordance with Clause 9.2.7.

When additional stability elements are necessary, they shall bedesigned in accordance with Clause 9.2.6.2.

p j




S16 -2009

What’s New?

16.5.3 Verification of joist manufacturer’s design

Former Criteria

Tests used to be to the satisfaction of the buildingdesigner.

2009 edition reads

“test …as described in the testing procedure in Part 5(steps 1 to 4) of Steel Joist Facts (CISC 1980)”

p j




S16 -2009

What’s New?

16.5.14 Camber

New in this edition is this statement

Negative cambers to satisfy roof drainage requirementsshall be designed for appropriate rainwater pondingloads.

This new note is to tie several clauses together.

Note: For manufacturing tolerances, see Clause 16.10.9. Formaximum deviation between adjacent joists, or joists and

adjacent beams or walls, see Clause 16.12.2.5. For special camber requirements, see Clause 6.3.2.2.




S16 -2009

What’s New?

16.5.16 Welding

This clause has been shortened and simply states that weldingshall conform to Clause 24 and use specific welding procedures

that have been accepted by the CWB.

16.10 Manufacturing tolerances

These remain as before, except for one small change to theminimum camber an OWSJ shall be manufactured.

Was 3 mm & changed to 4 mm




S16 -2009

What’s New?

16.12.2 Erection tolerances

Again, remains mainly as before, but for the addition of a singlestatement to Clause 16.12.2.5 dealing with deviation inelevation between adjacent joists.

New statement deals with adjacent walls and beams and states:

“The maximum shall also apply to joists adjacent to beams orwalls.”

17 Composite beams, trusses, and joists



S16 -2009

What’s New?

Biggest change in this clause is to the manner by whichdeflections due to shrinkage strains are calculated.

This is also reflected in changes to the Annex H dealing withdeflections so caused.




S16 -2009

What’s New?

Deflections due to shrinkage strain

For the component of the overall deflection due to shrinkage ofconcrete use:

1 - a selected free shrinkage strain;

2 - strain compatibility between the steel and concrete;and,

3 - an age-adjusted effective modulus of elasticity of

concrete as it shrinks and creeps




S16 -2009

What’s New?

Values you’ll need (Annex H)

1 - c = empirical coefficient used to match theory with testresults (Annex H: = 0.5)

2 - f = free shrinkage strain of concrete(Annex H: = 583 × 10 –6 )

3 - = aging coefficient of concrete (Annex H: = 0.73)

4 - = creep coefficient of concrete (Annex H: = 2.7)




S16 -2009

What’s New?

Basic expression for s:

where

c = empirical coefficient used to match theory with test results

ess

c f

s

I n

y Ac

L L

88

22

'/ cs E E n

)1/(' cc E E

)(85.0 25.0

stsses I I p I I




S16 -2009

What’s New?

Shear studs

When studs are in ribbed slabs with ribs parallel to the beam,several changes in determining shear stud resistances.

a) 3.0 > wd /hd 1.50

b) wd /hd 1.50

rs

d

rsrr qh

w

qq

5.1167.075.0

rscc

d

d scrr q f sd f dh

hwq 75.0)(11)(92.0 2.0'8.0'




S16 -2009

What’s New?

Channel connectors

For channel shear connectors in solid slabs of normal densityconcrete

')5.0(45 ccscrs f Lwt q



18 Composite columns



S16 -2009

What’s New?

New values of c and 1 apply here as well in determining theaxial compressive resistance of the concrete, C’ r

For bending resistance of HSS,

c is replaced with 1.18 1 c

18 Composite columns 20



S16 -2009

What’s New?

18.3 Partially encased composite columns

New clause:

18.3.3 Bending Resistance

For strong axis bending

For weak axis bending

''eC eC M r r rc

'

1

' )(18.1 ccr f t baC

'

1

' )2(18.1 ccr f t baC

18 Composite columns



S16 -2009

What’s New?

18.3 Partially encased composite columns

New clause:

18.3.4 Axial compression and bending

Basic interaction expression with biaxial bending

1rcy

fy

rcx

fx

rc

f

M

M

M

M

C

C

General

20 Plate walls



S16 -2009

What’s New?

General

Clauses have been reordered

Wording improved

Explicit link to Clauses 27.9 and 27.10 for additionalrequirements when under seismic loading

Additional requirements for limits on flexibility of

boundary elements for the extreme panelsInfill plates may have:

Unreinforced circular perforations (holes)Quarter-circular cut-outs at upper corners under defined

circumstances

All of the above is found in Clause 27.9

20 Plate walls



S16 -2009

What’s New?

Angle of inclination:

New statement added

When the aspect ratio of the panel lies within the limits0.6 L/h 2.5,

the angle of inclination from the vertical, , of the inclined pin-ended strips may be taken as 40°.

Otherwise, it shall be between 38° and 45° determined as wascase in S16-01.

20 Plate walls



S16 -2009

What’s New?

20.5 Limits on column and beam flexibilitiesColumns - Unchanged from 2001 edition

Beams - New requirements for minimum moment of inertias forextreme panel boundary beams, i.e. top and bottom of the wall.

General expression is

a) < 2.5 for beams at top panel of wallb) < 2 0 for beams at bottom panel of wallc) > 0.84h (flexibility limit for column)

25.044

47.0

Lw

I L

I h

bc

L

20 Plate walls



S16 -2009

What’s New?

20.5 Limits on column and beam flexibilities

Beams: Minimum Ib to satisfy L

a) For top beam

b) For bottom beam if present

)/(650 4

4

c I wh L

wL

)/(267 4

4

c I wh L

wL

20 Plate walls



S16 -2009

What’s New?

20.7 & 20.8 Lateral support – beams & columns

New statement

For both beams and columns, the infill panel can’t be assumedto be providing lateral support.

20.10 Infill plate connections

1 - Must connect to surrounding beams and columns2 - Can use either bolts or welds

3 - Must develop tensile strength of the infill plate strip4 - Splices allowed but must meet item #3 above

20 Plate walls



S16 -2009

What’s New?

Seismic requirements

Types of plate walls

a) Type D (ductile) plate walls

b) Type LD (limited-ductility) plate walls

Both existed previously but new detail requirements have beenadded for both

20 Plate walls



S16 -2009

What’s New?

Type D (ductile) plate wallsType D (ductile) plate walls

R d = 5.0 and R o = 1.6

Substantially re written.

Where you find rules for perforated infill plates and corner cut-

outs.

Framed by rigidly connected beams and columns.

Infill plate to resist all of factored storey shear.

20 Plate walls



S16 -2009

What’s New?

Type D plate walls

1) Shear resistance

Vr=0.4FywLsin2

2) Probable yield force due to plate yielding taken as

R yTr value corresponding to R dR o = 1.3

20 Plate walls



S16 -2009

What’s New?

27.9.2.3 Perforated infill plates

Primarily a means to reduce capacity demand on other elements.

Make plate look like engineered Swiss cheese i.e., regular patternof perforations

How -by reducing shear capacity of infill plate but still allowingdevelopment of continuous diagonal tension fields at 45o.

Reduced shear resistance is

Vr=0.4(1-0.7d/Sdiag)FywLsin2

20 Plate walls



S16 -2009

What’s New?

27.9.2.4 Infill plates with corner cut-outs

Where? at upper corners

Why? to allow services to pass through the infill plate.

How? shape of quarter circles

How? connected to a reinforcement arching plate

27.9.3 Beams

20 Plate walls



S16 -2009

What’s New?

Class 1 and braced

May develop plastic hinge

Interstorey drift angle limited to 0.02 r

Act with column in moment frame to resist 25% storey shear

Design as beam-columns for gravity, lateral and tension fieldforces

Beam web-to-column connection requirements are specified

20 Plate walls



S16 -2009

What’s New?

27.9.4 Columns

Class 1 and braced.

Resist axial loads shear forces and bending due to tension fieldforces.

Shear yielding should be prevented.

Stiffened so that plastic hinging forms above base plate.

20 Plate walls



S16 -2009

What’s New?

27.9.7 Protected zones

Areas of inelastic straining of plates, beams and column bases

For beams, area from face of column flange to ½ depth of beamfrom plastic hinge

Bolt holes in beam web – follow connection requirements.

20 Plate walls



S16 -2009

What’s New?

27.10 Type LD (limited-ductility) plate walls

R d = 2.0, R o = 1.5

Meet requirement of Type D walls excepta) 60 m height limit

b) Simple connections of beams to columns permitted

c) Beams may be Class 2

d) Other specific exemptions enumerated (mainly those that

apply to moment frame actions)

Bolts:

13.12 Bolts and local connection resistance



S16 -2009

What’s New?

Bolts:New ASTM specification for twist off bolts of A490 strength level

– ASTM F 2280.

Resistance factor for bearing of bolts on steel Value increased from 0.67 to 0.80.

New requirements when dealing with tension and block shear

and bolt tear-out.

Moved from Clause 13.11(c) to Clause 13 12 1 2 (a) is theexpression for resistance of steel due to the bearing of

bolts in connections.

ubr r tdnF B 3




S16 -2009

What’s New?

13.12.1.2 Bolts in bearing and shear

a) Factored bearing resistance at regular and short slotted bolt

holes

b) Factored bearing resistance perpendicular to long slotted bolt

holes

c) Bolt shear resistance remains unchanged

ubr r ntdF B 4.2

ubr r ntdF B 3




S16 -2009

What’s New?

13.12.1.3 Bolts in tension

For bolts in tension subject to fatigue loading user is directed by

a note in this clause to Clause 26.5

13.13.2.2 Fillet welds

13.13 Welds



S16 -2009

What’s New?

Two changes

1) Recognizes that failure in base metal maybe an issue when

electrode severely overmatched but not generally the casefor normal fillet welds.

2) Multi-directional fillet weld strength addressedBasic resistance expression is

1 = orientation of the weld segment under consideration2 = orientation of the weld segment in the joint that is nearest to 90°

wuwwr M X AV )sin50.000.1(67.0 5.1

600/85.0

600/85.0

2

1

w M

For joints combining welds and bolts in same plane, the

13.14 Welds and high-strength bolts in combination



S16 -2009

What’s New?

j g p ,resistance is the largest of

a) Vfriction + Vr,trans + 0.85Vr,long

b) Vfriction + Vr,long + 0.5Vr,bolt andc) Vr,bolt

Vfriction = plate friction resistance component

= 0.25Vs when the bolts are pretensioned= 0 when the bolts are not pretensioned

Vr,trans = transverse weld resistance component (= 90°) Vr,long = longitudinal weld resistance component

= Vr for combination joints with only longitudinal welds andbolts ( = 0°)

Vr,bolt = bolt shear resistance

21.3 Restrained members



S16 -2009

What’s New?

The shear force carried by stiffeners, Vst, is now stated asfollows:

Vst = Vf -0.8 A wFs

21.8.1.1

21.8.1. Fillers in bolted connections



S16 -2009

What’s New?

Previously fillers > 6 mm had to be developed with bolts byextending filler beyond the splice material

New limit is 19 mm; andBetween 19 mm and 6.4 mm, must account for bending of thebolt unless filler is extended by reducing shear resistance.

21.8.1.2Reduction is as follows:

R v = 1.1 – 0.0158t

wheret = thickness of the fillers

B h

21.10 Fastener and welds in combination



S16 -2009

What’s New?

Both

Clause 21.10.1 New connections

andClause 21.10.2 Existing connectionswere deleted and now simply refer to Clause 13.14

Ch d t b l (f) t i l d th d “l ”

22.2.2 Use of pretensioned high-strength bolts



S16 -2009

What’s New?

Change was made to sub-clause (f) to include the word “long” to describe the slotted joint and the qualifying text wasmade to be parenthetical.

(f) connections using oversize or long slotted holes (unlessspecifically designed to accommodate movement)

22.3.5.2Bolt hole details for long slotted holes:

Plate washers or bars are no longer required for bearing-typeconnections in double shear.

Clauses 24.4 (welding) and 28.7.4.3 (special surfaces)

Joint surface conditions



S16 -2009

What’s New?

Deals with issue of welding through paint (coatings)Permits welding procedures to be developed and then acceptedby CWB

Meant to apply to(a) welding of joist shoes to supporting members;(b) joist bridging;(c) metal deck to supporting members; and

(d) shear connectors.HoweverHave welded joists to beams through one coat paints (e.g. CISC/CPMA1-73a) and horizontal bridging for decades without problems

W59 TC discussed at length and will ask S16 TC to withdraw based onan interpretation that the W59 TC made at last meeting

B ittle f act e is a f act e mechanism accompanied b limited

Annex L Design to prevent brittle fracture



S16 -2009

What’s New?

Brittle fracture is a fracture mechanism accompanied by limitedor no plastic deformation.

Affected:

Steel subjected to tensile stresses (from direct tension orbending) when the rate of applied loading is high, e.g., dynamicor impact loading.

Not affected:Statically loaded structures that are subjected to lowtemperature do not normally require the use of notch-toughsteel.

Main influencing factors:




S16 -2009

What’s New?

Main influencing factors:

(a) steel strength

(b) material thickness(c) loading rate (strain rate effect)

(d) minimum service temperature

(e) material toughness (usually Charpy V-Notch)

(f) type of structural element

Other factors:




S16 -2009

What’s New?

Other factors:

Control of discontinuities

Connection details

Welding procedures

Defect size

Residual stresses

Some things not meant to be welded e.g. HS bolts and nuts

Importance (primary tension, fracture critical, etc)

Weld metal toughness

Strain rate effect:




S16 -2009

What’s New?

Commonly used in CSA S6 CHBDC

Simply put, Charpy V notch test temperature is much warmerthan “design” temperature.

Rational - steel in service usually not subject to tensile strains at

rate of the Charpy V-notch impact test.

Test temperatures and Energy Levels




S16 -2009

What’s New?

Test temperatures and Energy Levels

For guidance to the designer, Annex L provides:

Four tables provide appropriate Charpy V-notch impact testvalues (temperature and energy) for various servicetemperature ranges, importance, and strain rate.

Fifth table gives values for weld metal

Some other factors:

Annex L Design to prevent brittle fracture 30



S16 -2009

What’s New?

Brittle fractures can occur in pieces with one or more of thefollowing processes that have been introduced during fabrication

Hot dipped galvanized

Cold-worked material

Holes

Arc strikesCombinations of hot-dipped galvanizing with extreme coldworking (bending)

Cold camberingRolling practice (straight or cross-rolled)

Additional information:




S16 -2009

What’s New?

Additional information:

Charpy V-notch testing

Mid three results of 5 samples tested

Sample position and orientation described in material standardssuch as G40.20/40.21

Usual orientation best represents possible crack formation

Annex K Structural design for fire conditions



S16 -2009

What’s New?

Entirely new Annex

Alternate methods permitted by NBCC

Provides design alternate to prescriptive methods

Clause 6.7 Requirements under fire conditions




S16 -2009

What’s New?

Clause 6.7 Requirements under fire conditions

Use one of the methods specified in Annex K.

1) Design by engineering analysis(an “alternative solution”)- New

2) Design by qualification testing(“acceptable solutions”)- Traditional approach using ULC listed assemblies

Annex K - Scope:




S16 -2009

What’s New?

Annex K Scope:

Criteria for the design and evaluation of structural steelcomponents, systems and frames for fire conditions.

Determination ofheat input,thermal expansion, anddegradation in mechanical properties of materials(strength and stiffness) at elevated temperatures

Performance objectives:




S16 -2009

What’s New?

Performance objectives:

Design to maintain the load-bearing function of the elementduring the design-basis fire.

Satisfy other performance requirements specified for thebuilding occupancy.

Deformation criteria of the load-carrying structure may be a keyobjective.

Forces and deformations can’t cause a breach of horizontal orvertical fire separation.

Load combinations:

D + TS + (L or 0 25S)




S16 -2009

What’s New?

D + TS + (L or 0.25S)

D = specified dead load

TS = effects due to expansion, contraction, or deflection caused

by temperature changes due to the design-basis fire(can be taken equal to zero for statically determinate structuresor for structures that have sufficient ductility to allow theredistribution of temperature forces before collapse)

= 1.0 for storage areas, equipment areas, and service rooms,and 0.5 for other occupancies

L = specified occupancy live load

S = specified variable load due to snow

Notional lateral loads are to be included

Structural design for fire conditions by analysis:

Design basis fire




S16 -2009

What’s New?

Design-basis fire

Identify the heating conditions for the structure related tothe fuel commodities and compartment characteristics

Localized fire

Post-flashover compartment fires

Exterior firesFire duration

Active fire protection systems

Temperatures in structural systems

Material properties at elevated temperatures:




S16 -2009

What’s New?

p p p

Table K.1Reduction factors for stress-strain relationship of steel at

elevated temperatures (Eurocode 3 and Eurocode 4)

Table K.2 Values for the main parameters of the stress-strain

relationships of normal weight concrete (NWC) andlightweight concrete (LWC) at elevated temperatures(Eurocode 2 and Eurocode 4)

Material properties at elevated temperatures:




S16 -2009

What’s New?

p p p

Figure K.1

Stress-strain relationship for steel at elevatedtemperatures (Eurocode 3)

Structural design:




S16 -2009

What’s New?

General structural integrityadequate strength and deformation capacity to

withstand the structural actions developed duringthe fire within the prescribed limits of deformation

Continuous load paths to transfer all forces fromthe exposed region, tothe final point of resistance

Structural design:




S16 -2009

What’s New?

Strength requirements and deformation limits

Construct a mathematical model

Base model on principles of structural mechanics

Evaluate model for the internal forces and deformationscaused by the design fire

Methods of analysis:

1) Advanced methods of analysis




S16 -2009

What’s New?

) yIncludes both a thermal response and the mechanical

response

Thermal response - temperature field in each structuralelement

Temperature-dependent thermal properties of thestructural elements and fire-resistive materials

Mechanical response - forces and deflections based onthermal response that

Account for deterioration in strength and stiffness,thermal expansions, and large deformations

Limits states - excessive deflections, connection fractures,and overall or local buckling

Methods of analysis:

2) Simple methods of analysis




S16 -2009

What’s New?

2) Simple methods of analysis

Applicable to individual members

Support and restraint conditions assumed unchangedduring fire

Thermal response modeled with a one-dimensional heat

transfer equation

The maximum steel temperature assumed constantthrough the cross-section

Factored resistances then determined

Tension members:




S16 -2009

What’s New?

Determine reduced steel properties for maximum steeltemperature (Clause K.2.4), and

Use these reduced properties in Clause 13.2 to determine Tr

Compression members - T < 200oC

Determine reduced steel properties for maximum steel




S16 -2009

What’s New?

temperature (Clause K.2.4), and

Use these reduced properties in Clause 13.3 to determine Cr

Compression members – T 200oC

d = 0.6n = as given in Clause 13.3.1

)()(1)( /12

T AF T T C y

dndn

r

)(

)()(

T F

T F

r

KLT

e

y

Flexural members - T < 200o

C




S16 -2009

What’s New?

Determine reduced steel properties for maximum steeltemperature (Clause K.2.4), and

Use these reduced properties in Clause 13.4 to 13.6 todetermine shear and moment resistances

Flexural members - T 200oC


)(50

T C S



S16 -2009

What’s New?

CK = 0.12

)(5.0

)(

)(1)()1()()(

u

PK PK PK r

S

T M

T M C T M C T M C T M

4.2500

800)(

T

T C S

Combined axial force and flexure:




S16 -2009

What’s New?

Use Clauses 13.8 and 13.9 with reduced steel materialproperties with axial and flexural resistance determined in

previous slides.

Composite floor members:




S16 -2009

What’s New?

Use a one-dimensional heat transfer equation for temperature ofbottom flange

This temperature then taken constant up to mid-depth of weband

Decrease linearly to top flange by no more than 25%

Then use Clause 17 and reduced steel properties

Other components and connections:

U Cl 13 ith d d t l ti t i




S16 -2009

What’s New?

Use Clause 13 with reduced steel properties at maximumtemperature



CISC Commentary:

CISC to adapt the AISC commentary to conform to Annex K




S16 -2009

What’s New?

CISC to adapt the AISC commentary to conform to Annex K

13-page document dealing with each clause in the Annex

Provides references and bibliography

Clause 27’s new topics:

Protected zones

Clause 27 Seismic design



S16 -2009

What’s New?

Protected zones

Buckling Restrained Braced Frames - BRBFs

Plate walls - already reviewed

Ordinary frames - Conventional construction

Structures other than buildings:

Clause 27 may be used provided that:




S16 -2009

What’s New?

Clause 27 may be used provided that:

The structure has a clearly defined seismic-force-resistingsystem

Requires a comparable level of safety and seismic performance

27.1.2 Capacity design




S16 -2009

What’s New?

Connections along the horizontal load path need to be designedfor forces corresponding to R

d

R o

= 1.3.

Need to have a ductile governing ultimate limit state.

27.1.4 Members and Connections supporting gravity loads




S16 -2009

What’s New?

Applies generally, unless explicitly exempted

Splices in gravity columns not part of the seismic-force-resistingsystem

Factored shear resistance for both axes

= 0.2ZFy /hs

of columns above and below

27.1.7 Probable yield stress




S16 -2009

What’s New?

Accounts for the fact that the average yield stress is alwayshigher than the specified minimum.

Today mill test coupons taken from flanges rather than webs forw-shapes and from flats of HSS.

R y = 1.1 and

R yFy 460 for HSS and 385 for other sections

27.1.8 Stability effects

N i l l d d P d l ff d b id d




S16 -2009

What’s New?

Notional loads and P-delta effects need to be considered

When sizing the energy-dissipating elements or mechanisms ofthe seismic-force-resisting system

When determining the limiting forces corresponding toR dR o = 1.3

NOT when determining member forces induced by yielding of

the energy-dissipating elements

27.1.9 Protected zones

Avoid structural and other attachments that introduce




S16 -2009

What’s New?

Avoid structural and other attachments that introducemetallurgical notches or stress concentrations

Unless engineered and forming part of the design system or

Forming part of a test assembly that satisfies the physical testrequirements of Clause 27.2.5.1.

Discontinuities created by fabrication or erection operations shall

be repaired.

27.2.8 Protected Zones

for (27.2 Type D (ductile) moment-resisting frames, R d = 5.0, R o = 1.5)

Regions at each end of the beams subject to inelastic




S16 -2009

What’s New?

Regions at each end of the beams subject to inelasticdeformations

Face of the column flange to one-half of the beam depthbeyond the theoretical hinge point

No abrupt changes in beam flange

ExemptedSpecially detailed reduced beam flangesBolt holes in web

27.2.8 Protected Zonesfor (27.2 Type D (ductile) moment-resisting frames, R d = 5.0, R o = 1.5)

Clause 27 Seismic design 40



S16 -2009

What’s New?

Where inelastic deformations are anticipated in columns

Area from the face of the cap or base plate to one-half ofthe column depth beyond the theoretical hinge point orthe column depth, whichever is greater

27.5 Type MD (moderately ductile) concentrically bracedframes, R d = 3.0, R o = 1.3




S16 -2009

What’s New?

Brace slenderness for certain seismic cases is limited to 70 for

HSS rather than the 200 for other members

27.5.6 Protected zonesfull brace length

elements that connect braces to beams and columns

27.6 Type LD (limited-ductility) concentrically bracedframes, R d = 2.0, R o = 1.3




S16 -2009

What’s New?

Tension-compression bracing, in which pairs of braces meet acolumn on one side between floors, may be used

Provided that the columns meet certain new requirements

27.6.6 Columns with braces intersecting between floors

Must resist the simultaneous effects of




S16 -2009

What’s New?

1 - gravity loads2 - axial loads, shear forces, and bending momentsinduced by yielding and buckling of the bracingmembers at the design storey drift.

3 - out-of-plane transverse load at each brace-to-columnintersection point

Horizontal struts must also be provided between columns at the

brace intersection point levels

27.7 Type D (ductile) eccentrically braced frames, R d =

4.0, R o = 1.5

Add d li k d f b il b l i h




S16 -2009

What’s New?

Added are links made of built-up tubular cross-sections where

Vp = 0.55(2w)dFy for tubular links in beams

CJPG welds must be used to connect the webs to the flanges

but inaccessible backing bars need not be removed

Slenderness limits and a minimum stiffness are also required

27.7.6 Link stiffeners

Links with wide-flange cross-sectionsno change




S16 -2009

What’s New?

Links with built-up tubular cross-sections

new provisions are detailed in the Standard

27.7.13 Protected zone

Link beams are a protected zone

Extent: one-half of the depth of the beam beyond the ends ofthe link beams

Welding on link beams to attach link stiffeners is permitted

Buckling restrained braces

Generally patented systems

Often made of a steel plate inside a steel tube (round or square)




S16 -2009

What’s New?

p ( q )stuffed with grout.

Steel plate extends beyond steel tube

Connection made to steel plate not the tube.

Tube contains groutGrout and tube restrain buckling of the plate under compressiveforces.

Plate tends to buckle like a series of sinusoidal waves along therestrained length

27.8 Type D (ductile) buckling restrained braced frames,

R d = 4.0, R o = 1.2

Provides R 4 0 and R 1 2




S16 -2009

What’s New?

Provides R d = 4.0 and R o = 1.2

Uses a new brace that restrains buckling to raise compressiveresistance to level of the tensile resistance

Knee and K-braced frames excluded

Height of BRBF = 40 m unless stable inelastic response

No height restriction when 35.0)2.0( aa E S F I

27.8.3 (BRBF) Bracing members

T C fA F




S16 -2009

What’s New?

Tr = Cr = fA scFysc

A sc = cross-sectional area of the yielding segment of the steelcore

Fysc = specified minimum yield strength or actual yield strengthof the steel core

27.8.3 (BRBF) Bracing members

Splices shall not be used in the steel core.




S16 -2009

What’s New?

Plates used in the steel core that are 50 mm thick or greatershall satisfy a specified minimum notch toughness

Must resist 2.0 times seismic storey drift

27.8.4 (BRBF) Brace connections

Must resist probable tensile and compressive resistances ofbrace




S16 -2009

What’s New?

brace

= strain hardening adjustment factor

= friction adjustment factor

ySC ysc ySC F R AT

ySC ysc ySC

F R AC

27.8.6 (BRBF) Testing

2.0 times the seismic design storey drift




S16 -2009

What’s New?

and greater than 1.0.

27.8.7 (BRBF) Protected zone

steel core

elements that connect the steel core to frame members

27.11 Conventional construction, R d = 1.5, R o = 1.3

Heights > 15 m permitted when




S16 -2009

What’s New?

and not part of assembly occupancy

Increase factored seismic force

2% / m < force from R dR o = 1.3

35.0)2.0( aa E

S F I


Heights 40 m permitted when




S16 -2009

What’s New?

or


75.0)2.0( aa E S F I

30.0)0.1( av E S F I


Heights 60 m permitted when




S16 -2009

What’s New?


75.0)2.0(30 aa E S F I


Clause 27.11.3 paragraphs (d) through (l) contain the rest ofh




S16 -2009

What’s New?

the

detailed conditions for these cases when conventionalconstruction may be used for heights in excess of 15 m.

Many thanks go to

Mik I Gil M E P E FCSCE

Acknowledgements



S16 -2009

What’s New?

Mike I. Gilmor, M.Eng., P.Eng., FCSCE

Vice-Chair, CSA S16 Technical CommitteeMember of the Standing Committee on Structural

Design

who prepared the summary of the changes made to

S16 that were incorporated in this presentation



S16 -2009

What’s New?

richard vincent_s16-2009.pdf

Documents