Part I-Offset Diaphragms. Copyright Materials. Course Description. This presentation is protected by US and

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1 Excerpts rom: Part IOffset s opyright Materials Presented y: Presentation updated to 0 I, SE 70 opyright McGrawHill, I y: R. erry Malone, PE, SE Senior echnical Director rchitectural & Engineering Solutions his presentation is protected y US and International opyright laws. Reproduction, distriution, display and use of the presentation without written permission of the speaker is prohiited. he Wood Products ouncil 04 terrym@woodworks.org he Wood Products ouncil is a Registered Provider with he merican Institute of rchitects ontinuing Education Systems (I/ES), Provider #G56. redit(s) earned on completion of this course will e reported to I ES for I memers. ertificates of ompletion for oth I memers and noni memers are availale upon request. his course is registered with I ES for continuing professional education. s such, it does not include content that may e deemed or construed to e an approval or endorsement y the I of any material of construction or any method or manner of handling, using, distriuting, or dealing in any material or product. Questions related to specific materials, methods, and services will e addressed at the conclusion of this presentation. ourse Description ateral force resisting systems in today s structures are much more complex than they were several decades ago, incorporating multiple horizontal and vertical offsets in the s, multiple irregularities, and fewer lateral resisting elements. his two part presentation will provide a rief review of the method used to analyzed these complex structures. In part, topics will include code requirements, how to recognize irregularities and discontinuities, how shears are distriuted through complex s, the method of analysis used to solve the transfer of forces across areas of discontinuity, and the analysis of flexile wood sheathed or untopped steel decking s with horizontal offsets.

2 earning Ojectives asic Information Discuss oundary elements, complete lateral resisting load path requirements and related code sections. ransverse oading SemiRigid Offset walls Inline walls Not effected Not effected ant. Examine ommon ypes of Discontinuities Examine common types of discontinuities and irregularities and discuss how to estalish complete lateral load paths across areas of discontinuity. Discuss the nalytical Method of nalysis Review an analytical method used for solving complex s and shear walls using ransfer s and the Visual Shear ransfer Method. Offset sexamples Review the analysis of flexile offset s for loading in the transverse and longitudinal directions. c r u ull cantilever No exterior Shear walls (Not recommended) Wc W Presentation ssumptions lexile wood sheathed or untopped steel deck s he method of analysis is also relevant to internal load path analysis within semirigid s. oads to s and shear walls Strength level or allowale stress design Wind or seismic forces (UNO). he loads are already factored for the appropriate p load comination. asic Information oundary Elements omplete oad Paths Method of nalysis ode References: SE 70 Minimum i Design oads for uildings and Other Structures t 0 I Design references: he nalysis of Irregular Shaped Structures: s and Shear Walls Malone, Rice Design of Wood Structures reyer, ridley, Pollock, oeen SEO Seismic Design Manual, Volume Wood Engineering and onstruction Handookaherty, Williamson Guide to the Design of s, hords and ollectorsnse, Mays

3 W ( plf) hord oundary Elements ut Str hord support ollector support receives shears from one side only. ollector receives shears from oth sides. hordperpendicular to the applied load and receives axial tension and compression forces. hord, ollector, and hord (my) erminology hord hord hord/ol lector D ollector hord/ol lector hord undamental Principles: shear wall is a location where forces are resisted (supported), and therefore defines a oundary location. Note: ll edges of a shall e supported y a oundary element. oundary Elements: hords, drag struts, collectors, Shear walls, frames oundary memer locations: and shear wall perimeters Interior openings reas of discontinuities Reentrant corners. and shear wall sheathing shall not e used to splice oundary elements. ollector elements shall e provided that are capale of transferring forces originating in other portions of the structure to the element providing resistance to those forces. oundary (typical) hord ollec ctor hord oundary (typical) Note: Interior shear walls without a collector or a complete alternate load path are NO OWED! hord t Required for all SD and wind hord Deflection if tie ollec ctor oundary hord oundary (ongitudinal loading) ollector Deflection if no tie hord Stru ut 4 asic Information oundary Elements omplete oad Paths Method of nalysis oundary hord Reentrant corner earing will occur if collectors are not installed at reentrant corner. oads Note: ll edges of a shall e supported y a drag strut,, shear wall or other lateral resisting element. Deflected curve if proper tie Deflected curve if no tie oundary Elements Shaped uildingsransverse oading

4 Offset shear walls / ollector rut 5 ollector 5 Open typ.) ollector ( / Vertical offset in MR Opening in diaph. / ollector ollector diaph. / D ollector Multiple Offset E offset / strut 4 4 Offset shear walls and struts nalysis: /strut Design shall e ased on a rational analysis omplete load path from point of origin to lateral force resisting element (includes memers and their connections and splices) Openings in shear panels that materially effect their strength shall e fully detailed on the plans and shall have their edges adequately reinforced to transfer all shear stresses. Str omplete ontinuous ateral oad Paths Offset shear walls / 5 ollector ollector ( 5 Open / Vertical offset in Opening In diaph. / ollector ollector diaph. ollector / Multiple Offset E offset / strut 4 4 Offset shear walls diaph. and struts rut Str ollector ( MR D diaph. /strut SE 70 section.0.t discontinuities such as openings and reentrant corners, the design shall assure that the dissipation or transfer of edge () forces comined with other forces in the is within shear and tension capacity of the. What does this mean? asic Information oundary Elements omplete oad Paths Method of nalysis Method of nalysis he Visual Shear ransfer Method Symol for ft x ft square piece of sheathing in static equilirium Y M X ds. Positive i Direction ransverse Direction (shown) Shears pplied to Sheathing Elements Unit shear acting on sheathing element (plf) Unit shear transferred from the sheathing element into the oundary element (plf) Shears ransferred Into oundary Elements

5 .. w=uniform load Resisting wall in () shears ompr. in () shear transferred () tension into oundary element Resisting wall in shears () ft. x ft. square sheathing comp. element symol at any location in the. Resisting () in wall () () tension shears orces orces Maximum Positive sign moment convention Negative diaph. Pos. shear elements Positive diaph. shear elements asic Shear Diagram Neg. ll edges of a shall e supported y a oundary element (, strut, collector) or other vertical lateral force resisting element (shear wall, frame). Shear Distriution Into a Simple he Visual Shear ransfer Method egend Unit shear transferred into oundary element Unit shear acting on sheathing element riutary width to left and right wall riutary width to center wall 0 vsw = 46 plf vdiaph h = 4 pl vdiaph h = 54 pl f f dd shears together for net shears 975 plf 4 plf 0 ollector force is equal to the area of the shear diagram Direct Net ollector shears shears force 487 plf raditional Method r ollector W=5 plf 0 shear distriution into 0 the collector plf plf 4 plf asic Shear Diagram 000 l 4 54 Shear 650 l =975(0) Visual Shear ransfer Method =9750 l (method used in later examples) =487(0) =9740 l (/ round off) 4 54 Vsw=46 vnet= l alculating ollector orces Positive sign convention Introduction to ransfer s and ransfer reas.. 4 W(plf) hord (support) ransfer (su): portion of a larger designed to anchor and transfer local forces to primary s/struts of the main. lector oll D D Ratio=4: Maximum ollector lector oll t discontinuities, such as openings or reentrant corners, the design shall assure that the dissipation or transfer of edge () forces comined with other forces in the is within shear and tension capacity of the. What does this mean? raming memers, locking, and connections shall extend into the a sufficient distance to develop the force transferred into the. What does this mean? hord (support) mean? support ongitudinal ollector (ypically a tie strap and flat locking are called out) ransfer area Drag st trut support ransfer Memers and Elements

6 Partial length collectors do not constitute a complete load path. his force must e transferred out to the main s. complete load path is required. Disrupted Resis sting force es ollector Resis sting force es hord hord d/ollector ransfer ( eam) D ollector ull depth Rotation of section Disrupted ransfer area NOE: ransfer area without transverse collectors ollector must extend the full depth of the transfer ransfer Mechanism hord d/ollector Main Main ransfer using eam concept hord ollector Sect. ypical callout MS4 tie strap x with (xx) 0d nails over x flat locking. ap 8 onto wall. ransfer rea Higher shears. Details unit are seldom shear (plf) transfer cut into locking /collector force diagram PlanPartial length collector earing perp. to grain? ont. tie strap over he length of the collector is typically determined y dividing the collector 4 force y the nailing capacity. (total)= 4 (Wrong!!) he collector is typically checked for tension only. ompression rarely No gaps allowed. checked. (Wrong!!) sheathing is not allowed to locking acts as ministrut/collector and transfer strut/collector tensio or compression forces. transfers (accumulates) forces into the next lock. ollector force distriution Example of Partial /ollector hord vnet=00(75)= 5 plf vnet =5 (75)= 50 plf he ransfer spect Ratio should e similar to the main. hord force at discontinuity Disrupted vnet=00(50)= 550 plf No outside force is changing the asic shear in this area o ollector (D support) D vnet =5 (50) = 475 plf ollector (D support) D depth Main o ollector length l D ransfer Main DD plf plf 5 5 plf plf asic Shear Diagram at transfer asic Procedure Method y Edward. Diekmann (a) V=, Shear = V D DD 75 plf Sutract from asic shears dd to asic shears a 50 plf No outside force V= (), Shear = V is changing the D DD asic ransfer Shears shear in this area nalogous to a eam with a concentrated oad. asic diaph. shear D shears D vnet= 00 (50) = 550 plf Net shear Direction of shear transferred into collector 5 plf 50 plf ollector 550 plf 475 plf Net shear 5 plf 5 plf collector Net direction of shears acting on collector Note: he net shears will not always e equal. Dir. of force on collector Resulting net shear diagram on collector Shear Distriution Into he ollector Place the net shear on each side of the collector Place the transfer shears on each side of the collector Sum shears on collector (ased upon direction of shears transferred onto collector). Shear left=5505= 5 plf Shear right=47550=5 plf ollector force=area of shear diagram collector=(55)(collector)

7 ransfer depth ( a) R hord, strut or shear wall R ransfer depth hord, strut or shear wall ( a) R R s with Horizontal Offsets ransfer D ollector hord / strut a rans sfer le ength ransfer D hord, strut or shear wall ( ) R ra ansfer Diaph h. length R hord, strut or shear wall ( ) R R Simple Span ransfer nalogous to a simple span eam with a concentrated load hord / strut a Propped antilever ransfer nalogous to a propped cantilever eam with a concentrated load Simple Span and Propped antilever ransfer s Example with Horizontal End Offset ransverse oading M=50 ft.k =74.9 l 5 ector s oll D c V= l D /R=.5: ollector w=00 plf lector s oll D c V=5 500 l Diaphr plf 5 M= l ree ody for 500 l Sign onvention l 4 ransfer and Net Shear 57. plf 4. plf 50 plf 57. asic shear diagram plf.. Pos. 4.9 l 07. Neg. D shea ar diagram v= 74.9(5) = 07. plf 50(0) v=50(07.) v=70(07.) 50 plf =4.9 plf = 7. plf (Net shear) (Net shear) l 74.9(5) v= = 50 plf 50(0) 74.9 l l 5000 l v=50(50) = 400 plf v=70(50)= 0 plf Net shear Net shear Sign onvention 500 l No net change Net change No net change occurs in D egend 4 75 plf asic shear (40 plf) ransfer shears =xxx plf Net D shears (asic shear / transfer diaph. shears)

8 4.9 0 l 74.9 l =74.9 l l 7. =74.5 l l =700 l =78.5 l 0 plf 57. plf net plf 0 plf =700 l =78.5 l ongitudinal hord orce Diagrams Sign onvention Sign onvention 57. =6000 l 7.4 plf net 07. plf net Special nailing along collectors Sum of shears to collector or highest oundary nailinggreater of =6000 l (this is not an insignificant force.) = l 50 plf net =750 l ransverse ollector orce Diagrams x 57. pl lf 0 plf x 85 plf x f 4. pl 4.9 plf x4 7. plf 70 plf Example with Horizontal End Offset ongitudinal oading 5.. Drag strut plf 4. plf 50 plf asic shear diagram 4/6/ 6/6/ heck the shear capacity of the nailing along the 6/ U ase I 0d 6/ U ase I 70 plf 6/ U ase I oundary locations Nailing allouts ransfer oundary (yp.) 4/6/ ransfer area oundary allout all nailing on drawings: Standard nailing oundary nailing ollector nailing oundary 00 plf hord 40 plf 60 plf Drag strut 5 0 plf 0 r and rds ollector D chor ransfer D ollector Drag strut 5 0 and rds ollector D chor 00 plf Drag strut Pos. direction 50 h hord

9 Vsw=5000 l vsw=500 plf plf net 0 l 700 l plf 8 0 Vsw=5000 l v=40.9(0.5)= 5.4 plf 700 l 5 iaphragm Di v=5.(4.5)=9.6 (4 5)=9 6 plf v=45.(4.5)=69.6 plf egend 8 v=5.(0.5)=4.6v plf (Net shear) plf asic shear (40 plf) ransfer shears Dia aphragm 700 l =xxx plf Net D shears (asic shear /D Shears) Pos. Neg l iaph... D 45. plf ransfer area plf f 40.9 pl 450 l 4090 l ransfer and Net Shear 45. W=0 00 plf W=4060=0 00 plf 50 Vsw=5000 l 5 Vsw=5000 l vsw=. plf 88. plf net Pos. direction 4 =700 l =700 l 8 5 = 89 l 0 =59 l plf net plf net 8 = 957 l =89 l =700 l plf net plf net 5.48=.4 4 plf 84.6=.4 plf 9.6 plf 69.6 plf =68 l =68 l plf =0.5 plf 5.4.6=0.5 plf 9.65.=4.5 plf =4.5 plf Resulting direction of shear in collectors and s =4.5 l strut 4050 l 45. Pos. direction plf net 4 ongitudinal and ransverse ollector/ orce Diagrams 50 Questions? his concludes I Presentation Part on Offset s R. erry Malone, P.E., S.E. Senior echnical Director WoodWorks.org Prescott Valley, rizona ontact Information: terrym@woodworks.org WoodWorks woodworks.org Events/Presentation rchives (slide handouts)free