Design Manual of Suspension Bridges

Changing Lives One Bridge at a Time

Volume 3: Suspended Pedestrian Bridge Part 1: Design and Analysis First Edion 2009

Foreword Bridges to Prosperity Suspended Bridge Manual Dear User:

Th  f ths u hs b v 32 ys  th kg. I 1977 Eg Rbt G    tp t th Bgug Dstt  Np t vw th b h susp bgs bg but by th s th. Hs pt tht fw uh  pg pt by th Nps Gvt  suppt by Hvts f Zuh, Swtz t h  pt ths zg thgy swh swh   Np. By th t 1990’s, th BBLL (Bug Bgs t th L Lv) h b  f th st sussfu vpt fstutu pgs  th w. Th y suss ws fw by pubshg th “Susp Sht Sp T Bg St Th Hbk  Dwgs”  2002 whh ws fw by th p f 2,500 bg  Np by 2008. Th pubshg f ths u  wth Hvts gg t t u st -uty gs  2003: Z P  Chs Rs. As w xp xp th Hvts uty ftbg pg t Af  L A, t b ppt tht th g Hvts wgs  t b vt t AutCAD,  th us vt t  vsu ft. Ths hgs  v t y f s f tg, but s t w th us wgs t b sy pt t h w uty, wg f hgs  tpgphy, tpgphy, vb sus,  utu. Lk Hvts fu,  t pubsh  u k ths vght. Ev wth th gus jupstt tg tg v f Hvts Hvts Np, t tk us 8 ys t g th xp ssy t  s  s y txt, ths us w wys b  wk  pgss, g t u vw  vs. Th vut, s,  spss tht  ths  pssb  t y t . But, I wu k t spy thk Pss Bkh (PB) f NYC f vg th Cs Dw uts t AutCAD, th Rty Cub f Nwpt Nws, 35 th Rty Cubs  th Rty Fu,  th vuts  st  th Bgs t Pspty sg t (Jy Jhs, Avy Bg, Z P,  Chs Rs) tht tbut s y hus t k ths pssb. I th s spt tht w us t fy us th Hvts us, w hby  th s. Ths u s  g   b fy p  stbut. W wu wu sk, hwv, hwv, tht y hgs  t th u  t y sh wth Hvts  Bgs t Pspty s tht w  ght bt, but tht yu s k y w us  hgs f  vb t  s w. Sy, Kth R. Ftz, Rt & Fu, Bgs t Pspty, I. 5007 C-126 Vty Bv. Yktw, VA VA 23693 www.bgstpspty.g

Volume Volu me 3: Suspended Suspended

Part Pa rt 1 Desi Design gn & Analysis Analysis

Introduction I 2003, Bgs t Pspty (B2P) st tv t Np t t wth th Swss gz Hvts t  but th b-susp bg thgy. Dsg  stu f th susp bg w tught   t Hvts’ pph t ppty bg bug t th uty v. Ov th pst 6 ys, Bridges to Prosperity has introduced the

hghy t   Susp Bg sg t uts   f th thgy  u th w. Th sgs u  th Vu 3 Susp Pst Bg Mu gt wth th Hvts Np Sht Sp T Bg Th Hbk tht ws t wth v 30 ys f xp  th utus gs f Np. Bgs t Pspty hs ut w th  utu hgs s w hv tk th thgy f Ethp t Pu. Th sgs hv b   pt t b sut th gv  f wk. Bgs t Pspty hs  stu ps  xp xbty  sg tvs  sg pss ts t su th susp pst bg s  y sustb p f us  vyg tpgph  ggph gs f th w. Th  fu pts t Vu 3: Susp Pst Bg Mu, stutu s fws: Part 1:

Design and Material Quanes

Part 2: Construcon Plans Part 3:

Construcon Guide & Quality Control

Part 4:

Operaons & Maintenance

As wth y ut sg, usg ssups ust b  by th g sg. Th fwg u w pt t pv bth ut wgs f us wthut  gg  sg gus f ths tst  bg uss t v wth ths us. F futh sg  g ssups f th Hvts Np Sht Sp T Bg Th Hbk, ty pt sg sts s w s y pt sg s  sts.

Volume 3: Suspended

Part 1 Design & Analysis

Volume 3 Suspended Pedestrian Bridge Part 1: Design and Analysis Table of Contents

Section 1: Suspended Bridge: Design Background 1.1 1.2

Dsg Lgs  Assups Lts

Section 2: Design Procedure 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10

Ovvw Aby Lv Suvy Dw p & x bg fus St Cb Szs: Cb k-up t Cut Rqu Nub f Ts Fz Ps f Fus St T & Ahs Dsgs St Cstu Dwgs Cp t F Dwg Dsg Exp

Section 3: Material Estimate 3.1 3.2 3.3 3.4 3.5 3.6

Volume 3: Suspended

Cb & Cps St Rft B Ct Dkg Oth Mts Mt Qus Exp


Section 1: Suspended Bridge Design Background 1.1

Design Loadings & Assumptions

Th fwg s ts bs  ssups us by Bgs t Pspty wh fyg  xtpg up th g bg sg. Thy  t b f f -g sgs, s  sgs  y pt usg th fwg s  ssups. Skp t S 2 f sg pss. 1.1.1 Liveloads

Bf stg  th bg sg, vfy wth  stutu g s  gus. Th Bgs t Pspty st f v s 3.11 kN/² (65 b/²). As t  AASHTO (1997), th v  u f 4.07 kN/² (85 b/²) f kg s xg 400 squ ft s sstt wth ASCE 7-95, “Mu Dsg Ls f Bugs  Oth Stutus.” Th u uts f th u pbbty f th g g  f th stutu bg fuy  t y gv   s sstt wth th gs xpt f  typ pst bg. Tt LL = 3.11 kN/, ssug 1.0 t wth 1.1.2 Dead Loads

Th  s th su f  sf-wghts f th bg ts. Bw s  tb f ssu szs  wghts, us  B2P sg ts.

Tt DL = 0.321 kN/, ssug 1.0 t wth 1.1.3 Wind Loads (Overturning)

A w  pp hzty t  ght g t th gtu xs f th bg sh b pp t 1.676 kN/² (35 b/²). Th sp w pssus  f  w vty f 100 s p hu. I suh s  st hs hgh w-vty quts: AASHTO A 3.15 (1997) y b f  th  . Gv th pjt p f th bg s 1.1 ts  hght: th sug w vtu f s 1.843 kN/. Tt WL = 1.843 kN/, ssug 1.1 t g hght

Volume 3: Suspended


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1.1.4 Load Combinaons

T ut th uuv v , h pssb  b ust b hk t  th xu tg s. Th fwg  bs w b us, xtt f Tb 3.22.1A  AASHTO (1997):

Futh ts f sg ssups y b f  S 5.

1.2

Limitations

Th susp bg s t f psts, vstk  y s t pb f ssg  th 1.0 t w k wth. Wg th k up t 1.5 ts s pssb s w, but qus  g vut th h, tw  kg ps. It s  tht y bys, s  tbks b wk ss, but   s ptb f ssg. Athugh th t w gs ppy s wth s sp, th s  sg t f 120 ts wthut  w guy stutus. Th gtu gty f th bg s ps by 120 ts wthut th  t suppt. W guys sgty s th v st f th stutu s tw (2)  bs  fu (4)  hs  qu. Th sg gu s s t t 1.0 t k wths. Isg th k wth thby ss bth th   v  thf qus  g t pt us. Futu s f ths u y u  gt ub f tvs Futh, f  st k s hs, th spg  s s. Nt tht th g Hvts Np sg u th st k gs  thf f st k s hs,  sg g s  ssy.

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Section 2: Design Procedure 2.1

Overview

Dsgg th susp b bg qus vy  th bkgu. Th fwg s w pv  stp by stp gu t sgg  bg fwg th p f th st suvy s ut  Volume 2 Feasibility & Topographic Survey . 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10

Aby Lv Suvy Bg p & Fx Fu Ls Cut Rqu Nub f Ts Fz Ps f Fus St T & Ahs Dsgs St Cb Szs: Cb k-up t St Cstu Dwgs Cp t F Dwgs Dsg Exp

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2.2

Abney Level Survey

If t  s y, pt  bg p suvy usg  Aby v. Rf Volume 2 Feasibility & Topographic Survey f pt ts.

2.3

Bridge Profile & Fix Foundation Locations

Ct  p skth f th st suvy. Us pts ‘L’  ‘R’ f th suvy t k th py  f th tws f th   ght s spvy. Vfy tht th  butt s th  s f th bk wh fg w st, wt t ’s bk. D  pts: • Sp  ts. Nt f su btw ‘L’  ‘R’  f t -tw sp •

Hght  btw ‘L’  ‘R’, f v t  suvy sht

•

Nt s  k typ  th s

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2.4

Calculate Required Number of Tiers

A u  s qu btw th wst pt  th b  th hghst pt tht th wt hs v h (HWL). Futh, th xu hght  btw th tw tws ust b   th th sp (L) v by 25,  fu pt f th sp. If ∆H (th hght  btw pts ‘L’  ‘R’)) xs ths ut,    f th tws s t b s. T pv qut   t quz s  v btw tw ss,  ust ut th qu ub f s; h  s 1.0 t t s th v f th bg tws tt th v f th bs. I  t ut th qu hght, th fwg f ust b kw; •

Span (L)  ts (ust b ss th 120 ts)

As th suvy pts ‘L’  ‘R’  v t th ft f fu t ft f fu, stt by ssug   1.40 ts  th s t u wkwy s t wkwy s sp. O wgs st, vfy th s. •

Height dierence (∆H) = Ev ‘L’ – Ev ‘R’

Stt by ssug tht h s hs  , s th v f th wkwy tws s 1.40 ts bv ‘R’  ‘L’ spvy (1.0 t f  , 40  f s pt, p th tw wg T1). Us th s v ssups  tu s us  th suvy: w s fu v = 100.00. •

Cable Design Sag (Bd) and Hoisng sag (Bh) (f N-Psth Cb)

Th b sg s th v p tht th b w p bw th wkwy ss. Th b s hst t  ss sg th s sg bus  th b s st, th sf-wght f th bg   t th g w sghty stth th b. As suh, th  wst pt s th sg sg, but th tu w pt tks bth t s. Less than 80 m 5.00% x L 4.00% x L

•

Greater than 80 m 4.55% x L 3.64% x L

Low point ‘f’

If bth ss  qu hght (∆H = 0), th th w pt s ty  th . If t, th Cut usg th fwg qu  us th w pt tx  th fwg pg.

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• Verify adequate Freeboard (Fb) Fb s th  qu btw th wst pt  th b  th hghst pt f th wt. A g y u  s th suggst fb vus   wth st tpgph s, but f g pupss, u fb  qu s s fws; - Mountainous gorges: 4.0 -5.0 meters - Flood Plains: 2.0 meters

Fb s v by tkg th w s v, subtg th sg vu ‘f’  subtg th v f th Hgh Wt Lv. If th vu f Fb s ss th qu, th sg ust s th ub f s  th   bth fus. Exp: A t vy suvy wth  sp f 60 ts, pt ‘L’ 2.0 ts w th pt ‘R’,   Hgh Wt Lv (HWL) t v 96.5 ts f th suvy; Low side elevaon = 101.40 meters Low point in cable (relave to low side) ‘f’ = 2.08 meters High Water Level (HWL) = 96.5 meters

Okay

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Finalize Position of Foundations A sg th ub f s qu, th sz f th fu ftpt s kw. Ths stp w vfy th yut  sg. If ft f fu suvy pts ‘L’  ‘R’ ust b v, tk  t t  suvy  t  st. • Vfy qut sp g  st f sp (Volume 2 Topographic Survey )

Soil

Rock

Mxu 35 g sp  s or u 3.0 ts f g

Mxu 60 g sp  k or u 1.5 ts f g

• Vfy sp ss th 120 ts btw ss • Vfy  hght  f tp f s (∆H) < L / 25 • Tk  sp  ut Dsg Sg, B. Vfy w pt ‘f’

• Cut Fb

• Vfy  gt th u w

Flood Plains: 2.0 meters

Volume 3: Suspended

Mountainous gorge: 3.0 meters


11

2.6

Select Tier & Anchor Designs

Th  tw typs f h sgs; Gvty Ahs  Du Ahs. Gvty Ahs y b us  y s  k s  thy y  ‘wght’,  t p v th h. As suh, th xv qu s sb. Du Ahs qu k s s thy y  f btw th k f  th pu t u. As suh, y h  ftu k s  ptb. S Volume 2: Feasibility & Topographic Survey f  f. Gvty Ah ps  spt t tw  subtgs; 0 - 60 t sps,  61 - 120 t sps. Eh ss us  (1), tw (2),  th (3)  tvs. A suy f Gvty Ah Ps fu  Volume 3 Part 2: Suspended Bridge Drawings  s fws: 0 - 60  1 T Gvty Ah 1G60 0 - 60  2 T Gvty Ah 2G60 0 - 60  3 T Gvty Ah 3G60 61 - 120  1 T Gvty Ah 1G120 61 - 120  2 T Gvty Ah 2G120 61 - 120  3 T Gvty Ah 3G120 Du Ah ps  s spt t tw  subtgs; 0 - 60 t sps,  61 - 120 t sps. N futh ss s  s k hs  t  thsvs t  th  . Ths s u t th sht st btw th h  th ss, qu u t sp k s. T s th ub f s wu qu t st h ppy futh bk t th k, thus sg uty. Th  th szs f u hs; s, u  g. S (0 - 40 ts)  Mu (41 - 60 ts) hs  u  1D60, Lg (60 -120 ts) y b fu  1D120. A suy f Du Ah Ps fu  Volume 3 Part 2: Suspended Bridge Drawings  s fws: 0 - 60  61 - 120 

2.7

1 T Du Ah  Rk 1D60 2 T Du Ah  Rk 1D120

Select Cable Sizes: Cable Look-Up Tool

Bgs t Pspty t  Ms Ex Cb Lk-up T, vb t th wbst t www. bgstpspty.g/sus. Th Cb Lk-up T qus th us t put th bkg stgth ( f t s bkg f) f vb b  pus,  bs  y ub f b ub bs, utputs th xu sp wb f  gv k wth. Bf usg th t, sh vb st b  qust  Pf Iv stg bkg stgths f gv bs. Th Cb Lk-up T ssus tht th b hs  v g f 0.325%  s t f us wth -pstth b.

Volume 3: Suspended


12

Step 1 Rsh vb b bkg stgths. If pt  t ts  kwts (kN), vt t pus usg th fwg shps:

Step 2 Iput Bkg Stgth vus ( pus)  s ub f bs ( red txt).

Step 3 Mfy bs u s k wth hs vu t st s g s bg sp (yw). Exp: Iput 2 wkwy bs  2 h bs. Ty g wth 4 wkwy bs  2 h bs.

Step 4 Cut quty f b. Cs th sts f sv bs f b bf vg . O b s s by th  f 500 ts, s f  b qus sghty  th 500 ts, t y b wth th  st t s th sz f th b t u th ub f bs  thus th tt qu gth. Cut th quty f b t ; wh th st btw hs, wth   14 ts   4 pt gy t ut f b sg  wp-bk wth th hs. F th st vus f th Cstu Dwgs.

Volume 3: Suspended


13

2.8

Select Construction Drawings

F  gv sp, gg s  ub f s, tw (2) Abutt T & Ah wgs ust b st,  f h s f th v. Th Tw wg ts th 1.0 t k wth tw  s qu. Th (3) Dkg wgs ust b st f th 2  4 wkwy bs, wth tvs btw ssb s   s spvy.

Abutt T & Ah (Rght  L s qu) Gravity Anchors 0 - 60  1 T 1G60 0 - 60  2 T 2G60 0 - 60  3 T 3G60 61 - 120  1 T 1G120 61 - 120  2 T 2G120 61 - 120  3 T 3G120 Rock Drum Anchors 0 - 60  1 T 1D60 61 - 120  2 T 1D120 Tw

1.0  k wth

T1

Dkg P

2 wkwy bs 4 wkwy bs

W21 W41

Dkg S

2 wkwy bs 4 wkwy bs

W22 W42

Dkg Dt With Nailer

2 wkwy bs W23 4 wkwy bs wth N W43 No Nailer

2 wkwy bs N N 4 wkwy bs N N

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W24 W44


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2.9

Compile into Final Drawings

Cpt th bg sg by pg  qu bg wgs  g  bg p f th pjt. Iu  ss ug sp, pth f h, st t th bk f th h. St th fwg wgs; Gravity Anchor Right Side Gravity Anchor Le Side Tower 1.0  k wth Decking Plan Decking Secon Decking Detail With Nailer

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1G60 1G60 T1 W21 W22 W23


15

2.10

Design Example

A  p vy wth  60 t sp ws suvy. C pts f th suvy s fws: • Pt ‘L’ Ev (w s) = 100.0 ts • Pt ‘R’ Ev (hgh s) = 102.0 ts • HWL = 96.5 ts T ut th u ub f s, fy u fb (Fb) s gt th 2.0 t u s sp f  vy. Stt by ssug   (1.0 t hght pus 0.4 t s vg hght). Span

(L) = 60 ts

Elevaon low side walkway saddle = Elevaon high side walkway saddle = Height dierence (∆H) = Verify: Cable

Design Sag (Bd)

Low point ‘f’

Css f sp  ∆H  Dsg Sg Ev Cht = 2.08 ts

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Verify Freeboard ‘Fb’

Select Cable

Th b supp pv sps f  26  IWRC b wth bkg stgth f 30.0 t ts (68,343 pus). Usg th Cb Lk-up T, 4 wkwy k bs  2 h bs  qu, s thy  sut t  64 t sp.

Select Drawings

O , 60 ts  ss Rght butt = 1G60 O , 60 ts  ss L butt = 1G60 Tw Dwg= T1 Dkg P, 4 b = W 41 Dkg S, 4 b = W42 Dkg Dts, 4 b N = W43

Compile into Final Drawing

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Section 3: Material Estimate 3.1

Cable & Clamps

St st b bs  th t bkg stgths, usg th Cb Lk-up T  www. bgstpspty.g/sus. A sg th pu b, ut th quty t  by upyg th ub f bs by th fwg qu:

Th quty f ps p b s pt  th sz f th b  th typ f p st. Th tb bw s th Bgs t Pspty st f tqu quts f p-fg  b b ps t gv b  p ts. Cb p uftu pv sps tht ust b v s ths ht s y gv s  gu. Drop-forged clamps are of superior quality and must be purchased whenever possible .

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3.2

Steel Reinforcement Bar

Towers - 4 ps st b, 16  x 4.50 ts  gth - (# f wkwy bs + 2) ps, 16  x 20 

Decking Suspenders - (Tw th (Sp + 1) ps), 8  sth, ut t 1.80  Gravity Anchors - Sps 60 ts  ss (S  Mu) - 4 ps st b, 20 , 2.90   gth; - 11 squ gs, 10 , ut t 2.20  h, bt t squs 0.50  p s - Sps 61 -120 ts (Lg) - 8 stght bs, 20 , 2.90   gth; - 11 squ gs, 10 , ut t 3.35  h, bt t squs 0.80  p s Rock Drum Anchors - Sps 40 ts  ss** - Ah s, 16 ps, 25 , ut t 1.50 ts - I u: 8 ps, 10 , ut t 3.40 ts, bt t 0.90  t  - Out u: 8 ps, 10 , ut t 5.25 ts, bt t 1.50  t  - Sps 41 - 60 ts - Ah s, 20 ps, 25 , ut t 1.50 ts - I u: 8 ps, 10 , ut t 4.15 ts, bt t  1.15 t t - Out u: 8 ps, 10 , ut t 5.90 ts, bt t  1.70 t t

- Sps 61 - 120 ts - Ah s, 40 ps, 25 , ut t 1.50 ts - I u: 8 ps, 10 , ut t 4.15 ts, bt t  1.15 t t - Out u: 8 ps, 10 , ut t 5.90 ts, bt t  1.70 t t

3.3

Cement

Qus  gv  wgs. Su tgth th qus f T & Ah wgs f bth L  Rght butt  th  quty f th Tws. If t s t b us t xpt th ug , tk  t t th v 28 y stgth u . It s  t   th s f  f h pus. Th quty qu s sp  th put.

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3.4

Decking

Bgs t Pspty hss t us w kg wh v w s  vb p. Th  tw typs f w kg tvs: wth  wthut  ‘’. Th ‘’ s th s wth s th kg ps,  s h t th tp f th w ss-b t s th ut f suf  vb f g th kg ps. Th ‘’ pvs stutbty  ws f  s ssb sz but ss th tt gth f kg ps qu. It s up t th sg g t  f th  st s wt. Nailer (Recommended)

No Nailer

Dkg ps  ut t 3.0 ts f y sp v 60 ts  pfby  sps. If th bg s sht th 60 t sp, 2.0 t kg ps  wb. Th tt ub f kg ps s qu t [sp v by gth f h b (th 2.0  3.0)] up by v (5), s th w b v kg ps ss, h 15 - 25  w. If ‘s’  t b us,   (Sp pus ) ts f kg ps w b qu, ut t 1.0 ts. Cssbs: (Sp + 1) Dkg: (Sp / gth f h b (th 2.0  3.0) x 5) Ns (p): (Sp + 1)

3.5

Other Materials • Fxb Ps tubg: 5  t* • Fxb Ps tubg: 5  t* • Tyg W • Ns: 5” • U-s • Sws: 5/16 x 10  (4”) • A-sv pt • Fg: 1.50  hgh • Rg T • H Ss • Pt f tws • S/Gv • Msy Bk

3.5 t p b (Ah) 2.0 t p b (Tw) 10 kg 1 kg p  t 1 kg p 10  ts 1 p k p 1 g (3.8 L) p 50  ts Bg sp x 2 4 gs 4 ps 6 gs

* The best product for this purpose is reinforced sucon tube used by water trucks.

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3.6

Material Quantities Example

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21

Bridge Name:

Bridge Location: Span: Material List All prices are estimations, prices can change at moment of purchase, always verify Item Cable and clamps

Unit

Cable 26mm Clamps 26mm

m piece

Cable 32mm Clamps 32mm

m piece

Construction Materials Cement (6.4 x volume for concrete, 1. 1 x area for mortar) Concrete Blocks = 40 x 20 x 15 (cm) Rebar 12mm (1/2") Rebar 16mm (5/8") Rebar 20mm (3/4") Rebar 25mm (1") Handrail saddles Walkway saddles - 2 cable Walkway saddles- 4 cables Tying wire Plastic suction tube 3" Roofing Tar Deck Wood crossbeams - (10cm x 10cm) x 140cm Wood nailing panels - (5cm x 20cm) x 100cm Wood crossbeams - (10cm x 20cm) x 140cm Wood platform - (5cm x 20cm) x 200cm Screw - 8mm x 10cm(nailing panel to crossbeam connection) Nails - 15cm Smooth iron bar 10mm (5/16") (suspenders) Smooth iron bar 12mm (1/2") (j-bolts) Anti-rust paint (suspenders) Anti-rust paint (j-bolts) Safety fencing = 1.5m in height U-shaped nails Tying wire Local Materials Sand Gravel River rock Dressed Stone Transportation Transportation of materials (City - City) Transportation of materials (City - Village) Transportation of materials (Village to site)

Units required

Estimat ed Unit Pric e

$

-

$

-

$

-

$

-

$

-

$

-

Estimated Sub-total for Labor $

-

Total $ Contingency 10% $ Total with 10% Contingency $

-

bags of 40kg unit (9m) (9m) (9m) (9m) unit unit unit kg mts gal

piece piece piece piece unit kg (9m) unit 0.5gal 0.5gal mts kg kg

m³ m³ m³ m³

per trip per trip per trip

Misc. Tools and Tool Rental Misc. Tools* (listed below) Tool rental (winch and/or drill) Labor and Technical Support Mason Carpenter Supervision Logistical Support Logistical Support

daily daily daily per visit per visit

Materials Quantity Estimate Pg 1

Design Manual of Suspension Bridges

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