By R. Terry Malone, P.E., S.E.

SE University, February, 2015 www.LearnWithSEU.com

Load Transfer To And Through Shear Walls

Senior Technical Director Architectural & Engineering Solutions terrym@woodworks.org

Copyright Woodworks

By: R. Terry Malone, PE, SE Senior Technical Director Architectural & Engineering Solutions

terrym@woodworks.org

Based on 2012 IBC, ASCE 7-10 and 2008 SDPWS

Copyright McGraw-Hill, ICC

Presentation Based On:

T

Shear Wall

Hdr.

Collector

Chord

h1

Transfer area

Foundation

T

h2 Ve

rt. S

tep

in d

iaph

.

Chord

Load Transfer To And Through Shear Walls

1

Course Description-SEU

The method of distributing lateral forces through simple structures, has been generally understood for decades. However, with the increase in the complexity of plan layouts, understanding how to distribute loads into and out of shear walls is becoming increasingly more difficult. Topics will include how to maintain continuous load paths to shear walls, force transfer through shear walls with openings using the FTAO method and how to design In-plane and out-of-plane offset shear walls.

2

Learning Objectives-SEU

• Load Paths To Shear Walls Understand the detailing required to maintain continuous load paths to

shear walls.

• Shear Walls With Openings Determine how to design shear walls with openings using the FTAO

method of analysis. Special design issues will be discussed.

• Offset Shear Wall Design Understand how to design in-plane and out-of-plane offset shear walls.

• Offset Shear Walls Irregularities Understand the irregularities that are commonly caused by offset shear

walls.

3

Poll Question

Are you familiar with the design of wood shear walls? Segmented?

Yes No

Perforated? Yes No

Force transfer around an opening? Yes No

4

Standard Shear Walls

Segmented Walls FTAO Walls

Perforated Walls

5

Photo courtesy of Willdan Engineering

Segmented SW FTAO SW

6

No opportunity for perforated shear walls at exterior line

In-plane Offset Segmented Shear Walls

Hold Down (option 1) No irreg.

Wd

Hdr

Sill

Nail shtg to each 2x stud (option 2) Wd

Hold down (Typical)

Tie strap

Boundary nailing should be installed at each 2x stud at hold down and each plate

A

Compr. blocks required at all H.D. locations

Blk’g. or rim joist Analyze this Section as a transfer diaph. or transfer wall

Header/collector

Section C

Section B Section A

B C

Col

lect

or

C D

Alt. Config.

Sect. B

Anchor bolts or nails

Shear transfer Conn.

Tie strap

Nail shtg to each 2x stud

Load Paths

Type 4 vert. irreg. SDC B-F

Type 4 vert. irreg. SDC B-F

7

• Type 4 Vertical Irregularity, in-plane offset • ASCE 7-10 12.3.3.3 Elements supporting discontinuous walls SDC B-F • ASCE 7-10 12.3.3.4 25% increase in Fpx SDC D-F (connections)

Hold down (Option 2 -only)

Wd. Wd.

Wd.

Opening

Floor or roof sheathing

Blocking or continuous rim joist

Continuous rim joist, beam or special truss can be used as strut / collector or chord.

Double top plate can be used as strut / collector or chord.

Splice at all joints in boundary element

Opening

Column

Possible perforated or FTAO shear wall

Segmented shear wall

Header

Examples of Drag Struts, Collectors and chords at Exterior Boundaries

Sect.

Optional load path If balcony

Blocking (typ.)

Header

Direction of Load

8

T

Shear Wall (transfer wall)

Hdr.

Collector Chord

Chord

h1

Diaphragm sht’g. elevation

Diaphragm sht’g. elevation

Parapet (typ.)

Vert

. Ste

p in

dia

ph.

Transfer area

Complete Load Path to Foundation- Roof at Different Elevations-Chord Forces

Soil pressure

Chord force

Fo/t Fo/t

Foundation

Parapet (typ.)

Tie strap

T T

If strut action

Shear Wall

9

T

h2

No shear wall perpendicular to this wall at step

Blocking not full height. No diaph. Shr. Transfer (boundary nailing?). Truss top chords in cross-grain bending.

Cross grain bending at gang-nail plate

Assumed bearing of block against truss chord

Incomplete Load Path-Blocking Issues 10

Diaphragm 1 Diaphragm 2

Diaphragm 2 Boundary (typical)

Chord

Chord

Col

lect

or

Stru

t St

rut

Chord

Stru

t

Fundamental Principles: A shear wall is a location where diaphragm forces are resisted (supported), and therefore defines a diaphragm boundary location.

Note: Interior shear walls without a collector or a complete alternate load path are NOT ALLOWED!

Interior Shear Walls and Diaphragm Boundary Elements

SW1

SW2

SW3

Note: All edges of a diaphragm shall be supported by a boundary element.

Diaphragm 1 Boundary (typical)

• Diaphragm Boundary Elements:

• Chords, drag struts, collectors, Shear walls, frames

• Boundary member locations: • Diaphragm and shear wall perimeters • Interior openings • Areas of discontinuities • Re-entrant corners.

• Diaphragm and shear wall sheathing shall not be used to splice boundary elements. • Collector elements shall be provided that are capable of

transferring forces originating in other portions of the structure to the element providing resistance to those forces.

Required for Seismic and wind

1 2

B

3

C

A

11

Let’s take a look at load paths to the shear wall at grid line 2.

Special sheathing nailing required

Strut/truss (Call out force)

End nailed w/2-16d. This connection often has less capacity than the shears applied (e. g. nail capacity failure problem)

Cont. 2x plate w/ 16d at calculated Spacing (cross-grain or end nail failure problem)

16d at calculated spacing (truss to flat blk’g.)

Shear clips

Strut/truss (multiple if required)

Special sheathing nailing required, usually 8d or 10d at 6” o.c. or 4” o.c.

Configuration A

Configuration C Configuration B

Prying Cross-grain

If truss deflects

Optional Shth’g.

Strut/ truss

Typical Collector Framing and Connection Parallel to Shear Wall

Lateral distribution

a b

V

V

L/2 L/2

2x flat cross blk’g. at 24” o.c. w/2 or 4-16d to plate

12

Horizontal and vertical distribution

Typical interior Shear wall or braced wall

Roof trusses @ 24” o.c.

Roof diaphragm force to wall

No shear panels installed or detailed.

GWB ceiling buckling Trusses rotate because there

is nothing present to resist the lateral forces, and the lateral load is not transferred into the wall.

Collector / strut is missing

Typical Collector Framing and Connection Perpendicular to Shear Wall

13

Interior Shear Wall with Shear Panels and Collector Added

Shear panels vary in detailing from designer to designer (mini-shear walls). Add member at end of wall as required.

Trusses also brace wall

Continuous drag strut or collector is required

Tie straps at end of wall as required.

Ceiling

Shea

r wal

l hei

ght

Typical interior Shear wall or braced wall

Note: When designing the shear wall, the forces from the shear panels above must be transposed to the shear wall below.

Wall Perpendicular to Framing 14

Wood shear panels between trusses

Does not appear to have vertical blocking at truss (no shear transfer for vertical shear force).

Shear panel ratios 3:1

The shear panels shown are 24” wide by 6’-0” high. The framing could easily be 16” wide by 12’-0” high or greater.

Wall studs at 8” o.c.

If v=200 plf 400

400

1200

1200

2’

6’

Photo-Typical Shear Panels Courtesy of Willdan Engineering

15

If 3:1 A/R

Side members nailed to truss chords by side grain nailing, full height

Typical Shear Panel Detailing

Side members nailed to truss chords by side grain nailing-2 16d

Top and bottom members nailed to truss chords by end grain nailing-2 16d

Option 1 Option 2 Option 3

16

Blk’g. top and bottom only

Side frm’g. members added

Panel edge buckling

Add vertical nailing member in truss

These connections are part of the complete load path

Section A

Roof sheathing

Roof trusses

Splice strap 1 or 2 sides Blocking at tie strap

Shear panels per detail 3

Hold down straps as required Shear wall

2x blocking w/ shear clips (if req’d)

Single or multiple continuous drag members

Collector Framing Option 2 (Assuming the collector does not fall at a truss joint)

Special strut nailing full length

Connections for shear transfer

Blocking

A

Edge nailing each 2x block

Blocking

17

Section A

Roof sheathing Roof trusses

Shear panels per detail 3

Hold down straps as required

Shear wall

2x blocking w/ shear clips (as req’d.)

Shear clips as required

Special strut nailing full length

Connections for shear transfer

Blocking with nails and/or shear clips (as req’d.)

Edge nailing each 2x Horizontal strap is required across joint if 2x members can not be cont.

A

Single or multiple continuous drag members

Drag Strut Framing Option 3 (Assuming the collector does not fall at a truss joint) 18

Roof sheathing

Roof trusses

Shear panels per detail 3

Shear wall

2x blk’g.

Cont. drag members

Shear clips as required

Edge nailing each 2x Horizontal strap is required across joint if 2x members can not be continuous

A

Shear wall

Drag strut or collector Tr

usse

s (ty

p.)

A B

Section B

Special nailing

Shear panels

Special transfer area nailing (drag shear plus basic diaphragm shear)

Plan View

B

V

V F F

Special nailing required

Drag Strut Framing Option 4 (If the collector falls at a truss joint) 19

Truss joint

3’ 6’ 5.5’

14.5’

4’

3’

2’

1 2

A

B

3

C

D

4

9’

3.6

4500 lb 1.2 w=200 plf

(See recent Testing-APA Form M410)

Tie straps full length of wall per SDPWS section 4.3.5.2

Anchor bolts or nails

(Typical boundary Member)

Typical boundary member

2’ min. per SDPWS Section 4.3.5.2 (2008 requirement)

Many examples ignore gravity loads

FTAO Shear Walls

Cont. Rim joist

Strut/collector

Shear panels or blocking

20

Let’s talk about loads:

(b) Force Transfer Around Opening

Wall pier

Wall pier

Wall pier

Wall pier

Wall pier

Wal

l Pie

r he

ight

W

all p

ier

heig

ht

Wall pier width

Cle

ar h

eigh

t

Wal

l pie

r he

ight

Overall width AF & PA SDPWS Figure 4E

Dr.

Wall pier width

Boundary members

Collector (typ.)

Foundation wall

Allowable Shear Wall Aspect Ratios For FTAO Shear Walls

Notice: Not shown as having to comply w/ A/R

Wd.

Wd.

• Sections exceeding 3.5:1 aspect ratio shall not be considered a part of the wall.

• The aspect ratio limitations of Table 4.3.4 shall apply to the overall wall and the pier sections on each side of the openings

• Minimum pier width=2’-0”.

• A full height pier section shall be located at each end of the wall.

• Where a horizontal offset occurs, portions on each side of the offset shall be considered as separate FTAO walls.

• Collectors for shear transfer shall be provided through the full length of the wall.

Limitations:

21

4500

C

Tie strap/blocking full width

Blocking

Point of inflection is assumed to occur at mid-length (Typ.)

M M

V

V

V

V

M

M

1 2

A

B

3

C

D

4

C

A B

D

F

E

H G

I

L

J

K

T

V

V

M

M

M M

V

V

F=0 lb

F=0 lb F=0 lb

M

F=0

M F=0 Force Transfer Methodology (Diekmann)-Vierendeel Truss/Frame

F=0 lb

F F

Gravity loads to wall

1343.1 4243.1 22

w=200 plf

N.A.

4500 lb

4’

14.5’

208.62 lb

208.62 lb

991.38 lb

587.08 lb

F1B.5

VB.5

1 2

A

B

3

A

B

4

2’

2’

4500 lb

200 plf

200 plf 0=∑M

0=∑MB.5

B.5

2691.38 lb F4B.5

3912.92 lb VB.5

B A

C

A

I

G

B

H

C

V2.5 3’

3’

Free-body of Upper Half and Upper Left Section

Point of inflection

I

H

23

A

C

D

B

F

587.08 VB=587.08

VB.5=587.08 (587.08)

Vc=587.08

587.08

V2.5

1551

.7

V2

(1343.1)

3’

3’

F2b(V) 391.39

F2C(v) 391.39

991.

38

V2

391.

39

(208.62)

F2A

F2B(H)

1381

1037.1

1160.3

F2C(H)

F1B 600

F1C 182.77

E

(0)

(0)

573.23

2’

2’

2’

1 2

0=∑M

0=∑M0=∑M

0=∑M

0=∑M

0=∑M

Units are in lb

Corner tie strap force

Corner tie strap force

H G

J

I

K L

1591

.38

(991

.38)

V3

268.8

1937.1

1551

.7

1551

.7

236.17

3676.6

V3

(4243.1)

(2691.38) VB.5=3912.92

VB=3912.92 3912.92

(3912.92)

VC=3912.92

3912.92

(0)

5.5’

3’

2’

2’

2’

F3(V) 1422.88

F3B(V) 1422.9

F4B 1268.5

F4C 4114.3 F3C(H)

F3B(H)

F3A A

B

3

C

D

4

0=∑M

0=∑M

0=∑M

3’ 3’

3’ 3’

2.5

B.5 B.5

2124.9

1551.7

(4500)

(4500)

F2.5A 1274.9

(xxx) Shears and forces determined in previous step.

0=∑M

0=∑M 0=∑M

200 plf 200 plf 200 plf 200 plf

F2.5C

Resultant Forces on Wall Segments

0=∑V

0=∑H

0=∑V

0=∑V

0=∑V0=∑V

0=∑H

0=∑V

0=∑H

1551.7

1706.9 931 931 931

24

25

Complete Example with narrative and calculations

http://www.woodworks.org/publications-media/solution-papers/

Download Process: • WoodWorks.org website • Publications-Media tab • Wood Solutions Papers

http://www.woodworks.org/wp-content/uploads/Irregular-Diaphragms_Paper1.pdf

3’ 6’ 5.5’

14.5’

4’

3’

2’

1 2

A

B

3

C

D

4

T.D.2 T.D.1

2.67’ 2.67’

9’

3.6

4500 lb

Support

Support

Support

Support

1.2

Example -Blocking and Strapping Partial Width (with uniform load)

w=200 plf

Use results from previous example

Check aspect ratio of transfer Diaphragms/walls

2x blk’g. full depth of TD

Tie straps full depth of TD Transfer

diaphragm sections

26

3676.6

1551

.7

4243.1

1937.1

Transfer Diaphragm Shears and Net Shears using loads and forces from previous example

2.67’ - +

1937.1

3676.6

281.1

2020.6

v= 281.1 2.67

= - 105.3 plf

v= 1656 2.67 = +620.2 plf

v= 2020.6 2.67 = -756.8 plf

-105.3

-756.8

+620.2

+471.5 +408.6

A

B

3

C

D

T.D.2

Sign convention

Transfer diaphragm shears

1591

.4

vnet=349.23-105.38 =+243.93 plf

vnet=349.23+620.2 =+969.45 plf

vnet=349.23-756.8 =-407.55 plf

1975.8

3.6

+303.3 +243.9

+1028.8 +969.5

+1028.8 +969.5

-348.2 -407.6

-348.2 -407.6 +471.5 +408.6

3677.1 lb (+408.57 plf)

4243.1 lb (+471.46 plf)

3143.1 lb (+349.23 plf)

Basic Shear Diagram Summing V=0

vnet=408.57-105.38 =+303.27 plf

vnet=408.6+620.2 =+1028.8 plf

vnet=408.57-756.8 =-348.21 plf

408.6

408.6

408.6

471.5

471.5

471.5

w=200 plf

0=∑V

27

Fo/t

Pier Section Collector Force Diagrams

2.67’

- +

A

B

3

C

D

4

T.D.2

Sign convention

2.83’

Support

Support

Fbot

Ftop

Vtop

v3.6 v4 v3

Basic Shear Diagram

Summing

w

Transfer diaphragm shears

3.6

Fbot

Ftop

Vbot

28

Poll Question

Are you familiar with the common types of irregularities associated with offset shear walls?

Yes No

29

Offset Shear Walls

SW 1

SW 2

Col

lect

or

Collector

Collector

Out-of-plane Offsets In-plane Offsets 30

Potential buckling problem w/ supporting columns and beams

A

B 3

2

1

A.75

A.33

The deflection equation must be adjusted to account for the uniformly distributed load plus the transfer force.

Elements requiring over-strength load combinations

Transfer diaphragm grid line 1 to 3 See Section 12.10.1.1

ASCE 7 Table 12.3-2 Type 4 vertical irregularity-in-plane offset discontinuity 12.3.3.3 Discont. Walls SDC B-F 12.3.3.4 25% incr. SDC D-F

ASCE 7 Table 12.3-1 Type 4 horizontal irregularity-out-of-plane offset discontinuity in the LFRS 12.3.3.3 Discont. Walls SDC B-F 12.3.3.4 25% incr. SDC D-F

ASCE 7 Table 12.3-2 Type 4 vertical irregularity- in-plane offset discontinuity in the LFRS (if no H.D. at A.25) 12.3.3.3 Discont. Walls SDC B-F 12.3.3.4 25% incr. SDC D-F

Relevant Irregularities Per ASCE 7-10

Tables 12.3-1 and 12.3-2

A.25

31

Out-of-Plane Offset Shear Walls Assumed to act in the Same Line of Resistance

Loads

Col

lect

or

Collector

Collector

SW

SW

Transfer area

Offset

Discont. drag strut

Dra

g st

rut

Dra

g

stru

t

SW

Col

lect

or

Collector

Collector

• Offset walls are often assumed to act in the same line of lateral-force-resistance.

• Calculations are seldom provided showing how the walls are interconnected to act as a unit, or to verify that a complete lateral load path has been provided.

• Collectors are required to be installed to

transfer the disrupted forces across the offsets.

Discont. drag strut

Typical mid-rise multi-family structure at exterior wall line

ASCE 7-10 Section 14.5.2 Where offset walls occur in the wall line, the shear walls on each side of the offset should be considered as separate shear walls unless provisions for force transfer around the offset are provided. Check for Type 2 horizontal irregularity Re-entrant corner irregularity

32

Poll Question

Do you know how to analyze offset shear walls?

Yes No

33

Cant.

Mid-rise Multi-family

SW SW SW SW

SW SW SW SW SW

SW

No exterior Shear walls

Flexible, semi-rigid, or rigid??? 34

TD3

TD1

TD2

SW4

SW3

SW5

SW2

SW1

Diaphragm stiffness changes

Multi Story, Multi-family

1

2

3

Loads

I1 I2 I3

Higher shears and nailing requirements

ASCE7-10 1.3.5 - Cont. load Paths 12.1.3 - Cont. load paths-inter-connection ties 12.10.1-Openings, re-entrant. –transfer of dis-cont. forces combined with other forces 12.10.2-Collector elements

I1 I2

SW

SW4

SW3

SW5

SW1

1

2

3 Transfer Area Higher shears and nailing Reqmts.

Collector (typ.)

Higher shears and nailing Reqmts.

SW2

Col

lect

or

Stru

t/cho

rd

Bea

m

TD2

TD1

Stru

t

Main diaphragm

becomes TD3

Optional Framing Layouts

Collector (typ.)

35

SW 1

SW 2

25’ 20’

15’

200

plf

Drag strut

Cho

rd

colle

ctor

s

Cho

rd

80’

35’ 50’

Drag strut is discontinuous

1 2

A

B

3

C

4

10’ 25’ 5’

15’

200

plf

TD1 C

hord

co

llect

ors

Pos. direction + -

SW 3 SW 4

8’

8’

Drag strut

Collector

5’

12’ 45’

80’

Drag strut

Drag strut C

hord

Drag strut

Example 3-Diaphragm with Horizontal End Offset Longitudinal Loading-Out-of-plane offset Shear Walls

Assumptions: 1. Assume shear walls at grid lines B and C act along the same line of lateral-force- resistance. 2. Assume the total load distributed to grid lines A and B/C= wL/2 .

Offset SW

Offset SW

Support

Support

36

Diaphragm 2

Diaphragm 1

SW 2

35’

50’

1 2

A

B

3

C

10’

8’

Pos. direction + -

8’

2

SW 3

Pos.

40 plf 160 plf

200

plf

200

plf

SW 1

Vnet=Vsw-Vdiaph

Fend F2B

F2B

VA

VB

Basic Diaphragm Shears and Transfer Diaphragm Shear

Neg

.

200 plf

Vsw2=wL/2, vsw2=Vsw2/Lsw2 plf ∑ Vsw1, sw3, sw4=wL/2, vsw=∑V1,3,4/(Lsw1+Lsw3+Lsw4) plf

Determine Force transferred Into Transfer Diaphragm

Total Shear to Shear Walls (Assumed)

17’

SW 4

15’

F2B

VA

VC

VA

VC

VB

37

TD1 Diaphragm 2 Diaphragm 1

25’ 20’

15’

80’

1 2

A

B

3

C

No net change Net change in TD

No net change

35’

Net Diaphragm Shears

8’ SW 1

15’ SW 3 SW 4

SW 2

Pos. direction + -

50’

Vnet sw

Pos.

N

eg.

8’

4

V=Basic shear +/- TD shear plf

(Net shear)

Vnet sw

Vnet sw Vnet sw V=Basic shear +/- TD shear plf

(Net shear)

VA

VC

VA

VC

VB

38

15’

-

F2B

F2B

1

2

A

B

3

C

Transverse Collector Force Diagrams

8’ SW 1 8’ SW3 15’ SW 4

Pos. direction + -

SW 2

Net shear

Special nailing

So far, so good

Net shear (TD tension chord and Diaph.2 compression chord)

Net shear -vB

+vC

x1’

x2’

+F

-F

F3B

F3B

Diaphragm 2

39

25’ 20’

15’

80’

F= F2B

Fstart

F3C

1 2

A

B

3

C

Longitudinal Strut Force Diagrams

SW 4

Pos. direction + -

SW 2

15’

Fend

F2B

F4C = -xxx lb (Error)

F2A Fend

F3A

F4A=+xxx lb (Error)

Note: Neither force diagram closes to zero, therefore error. Notice that they do not close by the same amount.

8’

12’

8’

45’

5’ 5’ 10’

80’

SW 1

SW 3

Vnet sw

Vnet sw Vnet sw

Vnet sw

Fstart Fend

Fstart

40

4600 lb

25’ 20’

15’

80’

1 2

A

B

3

C

Adjusted Longitudinal Strut Force Diagrams (8% to 20% increase to B/C) [Amount shifted to B/C depends on the offset to span ratio of the transfer diaphragm]

SW 1

SW 3 SW 4

Pos. direction + -

SW 2

5400 lb

Line needs to move in this direction

The shear wall shears need to be higher in order to move the force diagram in this direction

Line needs to move in this direction

The shear wall shears needs to be lower in order to move the force diagram in this direction

Load distribution needs to increase towards line B/C. Increase the load to B/C by the amount off +/-.

Calculated forces

Revised forces

41

In-plane Offset Shear Walls

42

Wd

Hdr

Sill

Nail shtg. To each 2x stud

No hold down (option 1) Hold-down (option 2)

Blk’g. or rim joist

Sections do not comply with the required aspect ratio for a perforated or FTO shear wall.

4’

8’

8’

8’

12’

1’

2000 lb

3000 lb

Hdr/collector

Wd

Sill

DL=150 plf

DL=250 plf

SW2

SW1

6’

Example 4-In-plane Offset Segmented Shear Wall -with Gravity Loads

1’

Col

lect

or

VHdr=960 lb

VHdr=450 lb

A B C

ASCE 7 Table 12.3-2-Type 4 vertical irreg.- in-plane discontinuity in the LFRS if no hold down at B.

12.3.3.3 & 12.3.3.4 SDC B-F SDC D-F 43

Ends of wall panels do not line up. Requires special nailing of sheathing into stud below.

Nailing found in field was 12” o.c.

Requires same number of studs above and below with boundary nailing each stud Solid blocking

required

Photo-In-plane Offset Segmented Shear Walls

No hold-down below

Hold down

Hold down

44

Wall and Transfer Diaphragm Shears

5000 lb

8’

8’ 4’

2920 lb 1080 lb

+ +

2000 lb

8’

8’

+ Pos. direction -

5000 lb 1’

12’ 416.67 lb 416.67 lb

416.67 416.67 3370

1080

Upper Shear Wall

Rim joist

135 365

Col

lect

or

1080 lb 330 plf (incl. wall DL)

Lower Shear Wall

TD shears-lbs. (plf)

w=230 plf (incl. wall DL)

+ - 8’ 4’

SW2

SW1

+250

plf

+416

.67

plf

1260 (-157.5)

1020 (-127.5)

60 (+7.5)

1620 (+202)

2490 lb 9700 lb

+ + +

+

1 2

+424.1

+259.2

+618.7 +289.2

VHdr=450 lb

VHdr=960 lb

1260 lb (-157.5)

1620 lb (+202)

Sign Convention

+ shears

- shears

Aver.=250 plf +

+450 lb 3370 lb

Bas

ic S

hear

45

+ T

T

+ +

+

2000 lb

3000 lb 1’

8’

8’

8’ 4’

C

+ Pos. direction -

Vertical Collector Forces

2nd floor Rim joist

+ + SW1

SW2 D

epth

TD

1 2

+424.2

+259.2

+618.7

135 365

+289.2

Roof

+

T

C

+ +

+

2000 lb

3000 lb

8’

1’

8’

8’

8’ 4’ C

2nd floor Rim joist

+ + SW1

SW2

Dep

th T

D

1 2

+424.2

+259.2

+618.7

135 365

+289.2

Roof C

Horizontal Collector Forces

T

C

2490 lb 2490 lb

8’

416.67 365(8)+450=3370

9700 lb

VHdr=990 lb

416.67

Sign Convention Collector Force Diagrams

9700 lb

46

Conclusion:

Maintaining continuous load paths to the vertical lateral force resisting elements is essential. A load path is only as good as its weakest link.

Offset shear walls can create challenging design problems. It is important to recognize these issues and the irregularities they cause.

47

By R. Terry Malone, P.E., S.E.

SE University, February, 2015 www.LearnWithSEU.com

This Concludes Our Presentation on: Load Transfer To And Through Shear Walls

Senior Technical Director Architectural & Engineering Solutions terrym@woodworks.org

Copyright

48

CHALLENGE QUESTION:

Which type of Shear Wall is the answer to this session’s Challenge Question?

A. Perforated B. Segmented C. Force Transfer Around Openings (FTAO) D. None of the above

Please circle the answer that is announced so that you can use the information to complete your quiz (NY) or form (FL) for PDH.