FIP OUTSTANDING STRUCTURE AWARD WINNER

Design-Construction of Vranov Lake Pedestrian Bridge, Czech Republic

Jiri Strasky, Ph.D., P.E. Professor of Concrete Structures Technical University of Brno Czech Republic Consulting Engineers, SHP Brno, Czech Republic and Consulting Engineer Mill Valley, California

Jiri Strasky is Professor of Concrete Structures at the Technical University of Brno, Czech Republic . He also heads Consulting Engineers, SHP (Strasky, Husty & Partners), Brno, and works as a consulting engineer based in Mill Valley, Cal ifornia. Over the years, Dr. Strasky has been recognized for his innovative concepts in the design of long span concrete bridges and other structures. He received an Outstanding Structure Award from the Federation lnternationale de Ia Precontrainte (FIP) for his design of the Vranov Lake Pedestrian Bridge. Currently, he serves as Vice President (Czech Republic) of the FIP.

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Both structure and architecture were integrated imaginatively into the

design of the Vranov Lake Pedestrian Bridge by combining the

inherent advantages of precast concrete with both cable-stay and

external cable technology. The design demonstrates how the strength

and durability of concrete can result in a structure of exceptional

lightness and beauty that is also safe and comfortable for pedestrians

and bicyclists. With a ratio of d/1 = 7/630, the deck is one of the most

slender structures ever built. The aerodynamic stability of the bridge

is provided by the whole structural system, using the geometric

stiffness of the deck and external cables. An innovative application of

post-tensioning technology in the erection of the pylons and deck

facilitated a rapid and economical construction schedule with

minimal impact on the environment.

I n recent years, long-span concrete bridges have been designed pre­dominantly as cantilever or cable­

stayed structures. For long-span bridges intended for use only by pedestrians or bicyclists , two other structural types, derived from the old­est structural type of bridge, are par­ticularly suitable. These are the stress-ribbon and suspension type structures.'-7 In the case of the Vranov Lake Pedestrian Bridge in the Czech

Republic, the principles of the suspen­sion type structure were used.

The bridge is located in a beautiful, wooded recreation area where Lake Vranov was created by a dam in the 1930s (see Figs. 1 and 2). The structure replaced a ferry service carrying people between a public beach on one side of Swiss Bay and hotel accommodations, restaurants and shops located on the other side. The structure was also de­signed to carry water and gas conduits.

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Fig. 1 . Aerial view of Vranov Lake Pedestrian Bridge.

DEVELOPMENT OF STRUCTURAL SYSTEM

The pedestrian bridge was planned to connect with the existing roads used by pedestrians and bicyclists that lead from the village to the shore of the bay, and on the opposite side, from the beach into the wooded hills. The level of the water at the shoreline made it difficult and expensive to construct piers within the lake on which to sup­port the bridge structure.

To avoid erecting piers, a main span with a horizontal clearance of 250 m (820 ft) between supports was re­quired. Because the structure had to be sufficiently high above the surface of the lake (vertical clearance) to permit the free movement of sail boats be­neath the deck, the alignment of the deck is in a vertical curve.

Four types of structures were stud­ied as possible solutions for spanning the Swiss Bay. A cantilever structure was considered much too heavy (see Fig. 3) while a steel tied arch was thought to be too imposing for the landscape. In the stay cable solutions, the pylons towered above the trees. A suspension bridge produced the proper proportions for the given loca­tion (see Fig. 4) and at the same time proved to be economical to construct.

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Fig. 2. Completed bridge showing graceful lines of structure.

Longitudinal Arrangement

One possible problem identified early in the evaluation of the concept was the large effects of wind on sus­pension bridges. The bridge was de­signed to resist a wind velocity of 133 km/hr (82 miles per hour). Problems of vibration and overturning of light pedestrian suspension structures are well documented.8

A typical solution for overcoming vibration and overturning problems is

to form the deck with an open stiffen­ing steel truss of sufficient torsional and bending stiffness9 (see Fig. Sa). However, such a system was consid­ered to be too heavy and inappropriate for this particular bridge.

A deck of s treamlined steel box girders of the type often used in mod­ern highway suspension bridges 10 (see Fig . Sb), usually connected to the main cable at midspan of the main span to eliminate deformation and uti-

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Fig. 3. Structural type study- Cantilever bridge.

Fig. 4. Structural type study- Comparison of arch, cable-stayed and suspension bridge.

a)

b) u c)

lJ d)

Fig. 5. Four systems for stabilizing of the bridge: (a) truss deck; (b) streamline box deck; (c) incl ined suspenders; (d) cab le of the opposite curvature .

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lizing stoppers at the ends, was found to be too expensive for a pedestrian bridge.

Another approach to providing stiff­ness is to construct a slender concrete deck and stiffen the structure by a sys­tem of inclined suspenders (see Fig. 5c). Thi s design approach was con­ceived and developed by Professor Schlaich from Stuttgart, Germany. 11

The system has been used successfully in several projects . However, the maintenance of so many suspenders in this system becomes a difficult task.

A further approach to making the deck more slender would be to com­bine the process with techniques often used to stabilize utility bridges . In such cases, the concrete deck is stiff­ened by the post-tensioning of external cables with an opposite curvature to that of the main suspension cables (see Fig. 5d).

After studying all four of these sys­tems (by combining the pertinent fea­tures from each) and adapting to criti­cal constraints imposed by the project site and the alignment of the bridge, a novel structural system was developed.

The deck could only have one span in vertical arch alignment. There was

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d) L.

e)

t, a

~~ -t., !.c+sh I

- '\

I [MP]

2.0

............ --1.0

I . I

600 660 700 7 40 780 Lt[mm]

-+j-_-4-0 _.t--.-ao-f t. L, [mm]

Fig. 6. Longitudinal arrangement: (a) self anchored system; (b) suspension system; (c) partly self-anchored system; (d) erection of flexi ble member - compression of the bridge deck; (e) stresses in the flexible member- expansion joint.

a)

b)

>@]I:

PLAN

PYLON ELEVATION

Fig. 7. Transverse stiffening of the bridge: (a) deck suspended on V-shaped pylons; (b) deck stiffened by additional cables; (c) deck stiffened by bending stiffness.

also little space for the back cables be­yond the abutments. At fust glance, it appeared that the structure had to be formed by an arched deck fixed at the abutments and partly suspended on tension cables anchored into the an­chor blocks by back cables. By con­necting the abutments and anchor blocks, these two basic static systems

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- the arch and the suspension cable - can create a self-anchored system characterized by purely vertical reac­tions at their supports (see Fig. 6a).

To construct this system, however, the dead load would have to be sup­ported on scaffolding, which could not be done. Furthermore, the deck arch will shorten due to creep and shrink-

age of concrete and thermal effects; the cables likewise will shorten due to thermal effects. This creates tension stresses in the deck that the concrete cannot withstand.

To solve this problem, a partly self­anchored system in which the arched deck is suspended on the cables and is flexibly connected with the abut-

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Fig. 8. Architectural design- Elevation.

Fig. 9. Architectural design- Plan.

PYLON AND ANCHOR BLOCKS

'-CJ--o-

Fig. 10. Architectural design: anchor block and pylon- Transverse elevation.

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ments, which in turn are connected to the anchor blocks by prestressed con­crete tie rods, was developed (see Fig. 6c). For this system to be workable, it was necessary to first build the cables and then suspend the deck on them (see Fig. 6b).

The flexible members (expansion joints) are formed by tartan plates that were pressed against the already erected structure with an erection segment and jacks (see Fig. 6d). After compression was developed, the space between the abutment and the erection segment was filled with concrete and the segment was connected with the abutment.

The amount of compression was de­termined so that under the maximum shortening of the deck due to creep and shrinkage of concrete and temperature change, a minimum compression of 0.5 MPa (73 psi) remains in the joint (see Fig. 6e). In this way, the tension from the suspension cables partially post-tensions the deck and creates a system where compression stresses in the deck stiffen the whole structure.

For live load, temperature changes, and effects of wind, the structure forms a closed system where the load

PYLON AND ANCHOR BLOCKS

Fig. 12. Architectural model of bridge.

is resisted by both the compression ca­pacity of the concrete deck and by the tension capacity of the suspension ca­bles . Because the expansion tartan joints exhibit nonlinear behavior, the portion of the load resisted by the deck and the cables depends on the temper­ature and the age of the structure.

Tests conducted by the contractor for the bridge verified the excellent properties of the tartan plates. They allow large deformations without sig-

ELEVATION

Fig. 11 . Architectural design: anchor block and pylon- Longitudinal elevation.

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nificant changes in the stresses. Be­cause the plates are always under compression, they are also waterproof and can serve both as flexible mem­bers and expansion joints.

Transverse Stiffening

The required 3.40 m (11 ft) width be­tween the railings given by the Czech Standard and service requirements re­sults in a very narrow deck for such a

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3.40 + 6.60 I 3.40

a) b)

stiffening cable

TYPICAl SECTION

TYPICAL SECTION

Fig. 13 . Transverse stiffen ing of the bridge- Study for utility: (a) deck stiffened by additional cab les; (b) deck stiffened by bending stiffness.

30.0 252.0 30.0

Fig. 14. Longitudinal section of the bridge.

PYLON AND ANCHOR B.LOCKS

section E-E

1.50 t

tartan plates

external cable

20.50

30.00 252.00

LONGrTUOINAl. SECTION

Fig. 15 . Pylon, abutment and anchor blocks. For Sections A-A, B-B, C-C and 0-D, see next page.

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long span. Calculations made to deter­mine the stresses on the bridge due to wind indicated that these stresses were very large and that it might be necessary to stiffen the structure in the horizontal direction . Three feasible ways to ac­complish such stiffening were devised: • Suspend the deck on cables sup­

ported on open V-shaped pylons. In this plan, the cables provide stiffen­ing against horizontal movement (see Fig. 7a).

• Suspend the deck on cables an­chored from the top of triangular­shaped supports and stiffen it by two additional cables led in two inclined planes of the opposite curvature (see Fig. 7b). These cables would be connected with the deck by addi­tional suspenders and anchored at the bottoms of both pylons.

• Widen the deck from midspan to­ward the pylons, which would in­crease the bending stiffness of the deck in the transverse direction (see Fig. 7c). This widening, compared with widening the dec k to the midspan, brings only an insignifi­cant increase in load. The V-shaped pylon with mass con­

centrated at the top seemed inappro-

PYLON AND ANCHOR BLOCKS

section A-A

Fig. 1 6. Geometry of the deck.

priate for the site conditions. On the other hand, the A-shaped pylon natu­rally decreases in mass from the bot­tom to the top and creates a feeling of safety for users of the bridge. Increas­ing the deck stiffness eliminates a number of complicated connection de­tails of cables with the deck. There­fore, an A-shaped pylon together with

section B-B section C-C

9 .7 5

Fig. 15(cont.). Sections A-A, B-B, C-C and D-D of bridge on previous page.

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a widened deck was adopted for the final design.

ARCHITECTURAL AND STRUCTURAL SOLUTION The architectural design was devel­

oped from detailed studies (see Figs. 8 through II ). The author was looking

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1 a) b) c)

/ p

Fig. 17. Post-tensioning of the pylon: (a) bending moments due to dead load; (b) cable layout and equivalent forces; (c) bending moments due prestress.

for a structural solution in which the deck, its width and the shape of the pylon create natural , simple curves that blend into the surrounding land­scape (see Fig. 12). Aesthetic unity with the countryside was also accented by making all the suspenders and py­lons perpendicular to the curved bridge axis .

It was also felt that the water and gas conduits suspended on the deck would not only damage the architec­tural aesthetics of the bridge, but

DECK

would also complicate the mainte­nance (see Fig. 13a). Fortunately, the designer was successful in advocating the division of one large pipe into two smaller pipes for the water and gas conduits. This facilitated placing the conduits on outer cantilevers on the edges of the slender deck beyond the railings. The conduits were covered by steel plates to create an aerodynami­cally stable structure (see Fig. 13b).

A very slender deck only 400 mm (15.7 in.) deep is suspended on two in-

3.40 + 6.60

clined suspension cables of three spans 30, 252 and 30 m (98, 826 and 98 ft) long. The cables are deviated in steel saddles situated at the di­aphragms of the concrete pylons and anchored in anchor blocks (see Figs. 14 and 15). The pull from the cables is transferred into the ground by rock an­chors. The anchor blocks and the abut­ments are mutually connected by pre­stressed concrete ties .

Because the deck is in the vertical arch alignment, the designer was look­ing for a curve of the plan widening that together with the vertical curva­ture creates simple smooth curves. It was decided to use the simplest curve, namely, a circle (see Fig. 16). The outer edges of the deck form two cir­cles situated in two inclined planes. Their vertical and horizontal projec­tions are ellipses. The vertical and hor­izontal curvatures allow for stabilizing the structure by stiffening cables situ­ated within the edges of the deck; the cables pass across the expansion joints and are anchored at the end abutments. The function of these cables is similar to that shown in Figs. 5d and 7b.

LD 0

0 o::t

stiffening cable prestressing cable

+-~8~3~+~60~+-----------3._64_+~6~.8~4----------4+-6~0~+~8~3-+ 6.50 + 9.70

3.00 3.00 3.00

LONGITUDINAL SECTION

Fig. 18. Deck : typical cross section and longitudinal section.

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The deck is suspended at its outer edges on 3.00 m (9.8 ft) hangers that are perpendicular to the longitudinal axis. The deck is supported on both ends by two multi-directional pot bearings situated on the diaphragms of the pylons. The horizontal forces due to wind are transferred by steel shear keys.

The main cables are formed by 2 x 108- 15 mm (0.6 in.) diameter strands grouted in steel tubes. This configura­tion was derived from past experience with cable-stayed bridges where the stays were formed by strands grouted in steel tubes .12

·'3 In the case of the

cable-stayed bridges, the construction sequence was designed so that the steel tubes and the cement mortar used for the grouting are prestressed and act to transfer the stay tension due to live load and temperature changes.

The strands were tensioned before grouting . When the cement mortar reached 50 percent of its strength and the closing joints of the steel tubes were welded, the tension in the whole stay cable was released. The prestress­ing force was so high that when it was released, there was no residual tension in the mortar even under full live load. This arrangement not only increases the stiffness of the bridge but also reduces the fatigue stresses on the strands. The stays were carefully tested not only for loading by axial force but also for load­ing by a local bending mom~nt.

A similar arrangement was used for the suspension cables of the bridge. The increased tension in the strands was created by temporary loading of the already erected structure. Before casting the joints between the seg­ments, the deck was loaded by radial forces caused by the tension of the ex­ternal and internal cables temporarily anchored at the abutments. After grouting the suspension cables, the closure joints between the steel tubes were welded and the tension of the post-tensioning cables was released. In this way, compression stresses in the cement mortar and steel tubes were created (see Fig. 2lf).

The cables are fixed-connected to the deck at midspan. The hangers are formed from 30 mm (1.2 in.) diameter solid steel rods pin-connected to the deck and main suspension cables.

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ELEVATION

PLAN

Fig. 19. Model used for calculations- Elevation and plan.

fm = 0.298 Hz

t,., = 0.431 Hz

f171 = 0.789 Hz

Fig. 20. First vertical , horizontal and torsional natural modes and frequencies.

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The inclined pylons have an A­shape with curved legs connected by top and bottom diaphragms. The legs of the pylon were post-tensioned by draped cables to balance the bending stresses due to the curvature of the legs (see Fig. 17). During the erection of the structure, the pylons were sup­ported by pins; after erection, the py­lons were cast in the footings. The an­chor blocks protruding above grade were post-tensioned to the anchor foundation slabs by prestressing rods where rock anchors are anchored.

a)

d)

el

The deck was assembled from pre­cast double tee segments stiffened by diaphragms at the joints (see Fig. 18). The 3.00 m (9.8 ft) long segments have a variable width corresponding to the variable width of the bridge deck. The two end segments are solid. Steel pipe conduits for gas and water lines were placed on the outer, but not mu­tually connected, overhangs.

The deck was post-tensioned by four internal tendons and stiffened by two external tendons. The internal ca­bles of 12 - 15 mm (0.6 in.) diameter

strands are threaded through the whole deck and anchored at the end seg­ments . The solid end segments were also post-tensioned by prestressing rods. The external cables were formed by 2 x 108 - 15 mm (0.6 in.) diameter strands grouted in high density polyethylene tubes.

STATIC AND DYNAMIC ANALYSIS

The bridge was analyzed for both the static and dynamic load as a geo-

Fig. 21 . Construction sequences: (a) first stage pylon raising using temporary towers ; (b) and (c) second stage pylon raising; (d) erection of main suspension cable tubes; (e) erection of deck segments; (f) deck tendons stressed- before grouting of the strands of main suspension cables.

70 PCI JOURNAL

metrically nonlinear structure. For erection analysis, the bridge was ana­lyzed as a three-span perfectly flexible cable. For analysis under service loads, it was analyzed as a geometri­cally nonlinear three-dimensional frame structure with the deck modeled by the two edge girders and transverse diaphragms, the suspension cables, hangers and external cables by bars. The model used in the calculations ex­pressed the real boundary conditions and stiffening of the structure by ex­ternal cables (see Fig. 19).

The dynamic response of the struc­ture due to movement of people and wind was carefully analyzed. Fig. 20 shows the first vertical , horizontal and torsional natural modes and frequen­cies. Because of the low frequencies (the first 12 natural frequencies corre­sponding to vertical modes are under the walking frequency of 2 Hz) , the bridge proved not to be sensitive to pedestrian loading. Even the loading

Fig. 22. Raising of the pylon (second stage).

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imposed by "vandals" (a group of peo­ple trying to make the bridge vibrate in an eigenmode) caused negligible ef­fects with an amplitude of several millimeters.

The dynamic response to maximum wind load [at v = 37m/s (121 ft per sec)] reaches an amplitude of A = 40.7 mm (1.6 in.) in the horizontal plane at the third mode with the frequency 0.431 Hz and peak acceleration a11!S = 0.35 m/s2 (1.15 ft per sec2). This value is also less than the permissible accel­eration of ams, per = 0.50 m/s2

( 1.64 ft per sec2) considered for critical speed. Because it is nearly impossible to use the bridge in this severe wind , this value has only a theoretical value. When the wind speed is about 10 m/s (33 ft per sec), the acceleration is a ms

= 0.018 m/s2 (0.059 ft per sec2) , which is much less than the permissible ac­celeration of ams,per = 0.25 m/s2 (0.82 ft per sec2

) considered for this speed. Aerodynamic stability of the struc-

ture was also carefully studied. The structure proved to be stable from the viewpoint of vortex shedding and gal­loping. The aerodynamic flutter sus­ceptibility was checked by approxi­mate formulas published in Refs. 14 and 15. Because the calculated critical wind velocities were relatively low­from 23.5 to 45.5 m/s (77 to 149ft per sec) -the stability of the bridge was checked in the wind tunnel on the full aeroelastic model built in the scale 1:130. Measurements from these tests confirmed the aerodynamic stability of the structure. 16

CONSTRUCTION PROCEDURE

The methods of erection were devel­oped by the contractor. The most im­portant phases were construction of the pylons, erection of the suspension cables and assembly of the deck (see Fig. 21).

Fig. 23. Securing of the pylon.

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Fig. 24. Main suspension cab les before the erection of the deck.

Fig. 25. Suspension of a segment on the main suspension cables.

Figs. 22 through 28 show the various erection stages of the bridge structure.

Construction began with the casting of the anchor blocks and end abut­ments, followed by installation of the ground anchors. Some of the rock an­chors and prestressing rods of the an­chor blocks were tensioned. The py­lon s were cast in the horizontal position and were raised to the design upright position in two stages.

In the first stage, the pylons were raised to a partially upright position by the tension pull of the short vertical cables anchored at the tops of the py­lons and temporary towers (see Fig. 21a). The cables were pulled by hy­draulic jacks supported by steel anchor

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members situated on the steel girders, transferring the load to the towers . As the pylons were being raised, the tops of the pylon s moved in the circle curves, the steel anchor members had to move in a horizo ntal direction . Therefore, Teflon pads were placed between these steel members and the girders.

In the second stage, the pylons were raised into their fi nal design position by the tension pull of the cables an­chored at their tops (see Figs. 21 b and 2lc). The erection cables spanning the bay were pulled by hydraulic jacks. At first, the cables were tensioned so that tension in the cables balanced the dead load of the partially upright pylons.

Fig. 26. Structure during the erection of the deck.

Then, the temporary towers were re­moved and the first pylon was raised into the final position by the tension pull caused by the jacks situated at the second pylon. When the position of the first pylon was secured by the tem­porary cables, the second pylon was raised by the tension pull caused by the jacks situated at the first pylon. Then, its position was secured.

The cables used for raising the py­lons were also used in erecting the steel tubes of the main suspension ca­ble s through which strands were threaded. The tubes with suspenders were suspended on the erection cables and moved along them to the final de­sign position (see Fig. 2ld). The main

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Fig. 27. End view of structure showing erection progress of deck.

suspension cables comprised six ca­bles of 18 - 15 mm (0.6 in.) diameter strands that were threaded through the tubes the whole length of 300 m (984 ft) by a special device developed for this purpose.

The erection scheme for the deck was based on the method used for erection stress ribbon bridges where precast segments are being shifted along the bearing cables into the de­sign position.'-• The deck was progres­sively assembled in sets of 15 seg­ments (segment by seg ment) from midspan toward both abutments .

First, an erected segment was sus­pended on the erection truck that was moving on temporary cables anchored at the abutments. Using the tension pull of the erection cables, the truck with the segment was moved to the final design position, where the seg­ment was pin-connected to the already erected structure and hung onto the main suspension cables (see Fig. 21e).

During the erection of the first seg­ment, the temporary cables were sus­pended on the main suspension cables at midspan; during erection of all the

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Fig. 28 . Suspension cables hold ing deck.

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Fig. 29. Loading test of bridge structure.

other segments, the temporary cables were supported by low movable tow­ers situated at the face of the erected structure. The shape of the deck was continually changing from a concave design curve to a convex design curve in accordance with the deformation of the main suspension cables and the length of the hangers.

During erection of the segments, the remaining prestressing rods of the an­chor blocks and the ground anchors were post-tensioned to balance the pull of the main suspension cables, which increased during erection of the bridge. After the segments had been placed and connected, both the inter­nal and external tendons were ten­sioned (fr = 0.7J;,) and temporarily an­chored into the abutments (see Fig.

2lf). The steel tubes of the main cable were then welded and grouted.

Compression stresses were generated on the cement mortar and steel tubes when the tension of the internal and ex­ternal tendons was released. Then, the internal cables were cut and their an­chors were transferred to the end seg­ments. Finally, the joints between the segments were cast and the deck was post-tensioned by internal cables and rods anchored at the end segments.

The tartan expansion joints were placed between the end segments and the special abutment segments. Com­pression was created in the tartan joints using hydraulic jacks to press the abutment segments against the tar­tan members and the already erected structure. When the design compres-

Fig. 30 . Pedestrians and bicyclists enjoy the beautiful scenery around the bridge.

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sion was reached, the abutment seg­ments were connected with the abut­ments. Then, the external cables were again tensioned (J; = 0.3fu) and an­chored at the end abutments.

The completed structure was checked by detailed static (see Fig. 29) and dynamic tests that verified both the high quality workmanship and the accuracy of the design assumptions.

Construction of the bridge started in the spring of 1991 and was finished in the spring of 1993. Because of the recreation season from June to the middle of September and severe win­ter conditions, construction could take place only during the spring and au­tumn months. The cost of the bridge was about $1,000,000 at the time of completion.

CONCLUDING REMARKS

Although the Vranov Lake Pedes­trian Bridge has a very slender deck, pedestrians and bicyclists feel no un­pleasant bridge motion when walking or standing and admiring the sur­rounding landscape. The bridge is widely used not only for crossing the Swiss Bay, but also as a meeting place and for the sport of bungee jumping (see Figs. 30 and 31).

The structural system used in the design of the bridge proved to be safe, economic and minimally disrupting to the surrounding environment. The ar­chitectural design that was developed from careful structural studies has also

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Fig. 31. View of completed structure.

been well received. Indeed, the design of the bridge received an Outstanding Structure A ward from the Federation Internationale de la Precontrainte at the XII FIP Congress/40th PCI Annual Convention in Washington , D.C., in 1994.

The structural design of the main sus­pension cables, which was developed from the technology of modem stay and external cables, has proven to be very efficient and economical. As a member of the engineering design staff of T.Y. Lin International, San Francisco, Cali­fornia, the author completed the design study of the strengthening of the Mid­Hudson Bridge in Poughkeepsie, New York, in which the scheme employing the stay technology for suspension ca­bles was the most economical choice of four schemes investigated. The author continues to develop stress ribbon struc­tures stiffened by external cables and arches. At present, a similar suspension structure, which was designed by OBEC, Consulting Engineers, Eugene, Oregon, and the author, is being built across the WiJliamette River in Eugene.

CREDITS Design: Jiri Strasky, Consulting Engi­

neer, SHP Brno and Mill Valley , California

Construction Management: Ilja Husty, SHP Brno, Czech Republic

Construction Documentation: Jaroslav Jordan and Miroslav Spudil, Do­pravni Stavby & Masty, Olomouc, Czech Republic

November-December 1997

Checking : Marie Studnickova, Klokner Institute CVUT, Prague, Czech Republic

Wind Tunnel Test: Miroslav Pirner, Prague, Czech Republic

Contractor: Dopravni Stavby & Mosty, Olomouc, Czech Republic

REFERENCES I. Strasky , J. , "Precast Stress-Ribbon

Pedestrian Bridges in Czechoslo­vakia," PCI JOURNAL, V. 32, No. 3, May-June 1987, pp. 52-73.

2. Redfield , C., and Strasky , J. , "S tressed Ribbon Pedestrian Bridge Across the Sacramento River in Red­ding, California, USA," L'lndustria /taliana del Cementa , No. 663, Rome, Italy, 1992.

3. Strasky, J., "S tress-Ribbon and Sus­pension Pedestrian Bridges," Sympo­si um on Modern Prestressing Tech­niques and Their Application, Kyoto, Japan, 1993 .

4. Redfield, C. , and Strasky, J. , "Sacra­mento River Pedestrian Bridge," ASCE Structural Congress, Chicago, IL, 1996.

5 . Strasky, J. , "Precast Stress-Ribbon and Suspension Pedestrian Bridges ," lASS Symposium , Milan , Italy , 1995.

6. Strasky , 1. , "Suspension Pedestrian Bridge Across the Swiss Bay of Vra­nov Lake," Space & Society, No. 67, Milan, Italy, 1994.

7. Strasky, J. , "Architecture of Bridges as Developed from the Structural Solu­tion," Proceedings, XII FIP Congress/ 40th PCI Annual Convention, Wash­ington , D.C. , 1994.

8. Podolny, W., and Scalzi, J. B., Con­struction and Design of Cable-Stayed Bridges, John Wiley & Sons, New York, NY, 1976.

9. Endo, T. , Tada, K., and Ohashi, H., "Development of Suspension Bridges -Japanese Experience with Emphasis on the Akashi Kaiko Bridge," Confer­ence on Cable-Stayed and Suspension Bridges, Deauville, France, 1994.

10. Ostenfeld, K. H. , "From Little Belt to Great Belt ," Conference on Cable­Stayed and Suspension Bridges, Deauville, France, 1994.

II. Schlaich, J., and Schober, H. , "A Sus­pended Pedestrian Bridge Crossing the Neckar River Near Stuttgart," Confer­ence on Cable-Stayed and Suspension Bridges, Deauville, France, 1994.

12. Strasky, J. , Korenek, M. , and Mencl, V., "The Cable-Stayed Bridge Across the River Elbe near Podebrady," L'In­dustria ltaliana del Cementa, No. 649, Rome, Italy, 1990.

13. Strasky, J. , "Design and Construction of Cable-Stayed Bridges in the Czech Republic ," PCI JOURNAL, V. 38, No. 6, November-December 1993, pp. 24-43.

14. "Bridge Aerodynamics - Proposed British Design Rules," Proceedings, Conference of the Institution of Civil Engineers, London , England, March 25-26, 1981.

15. KJoppel , K. , and Thiele, P. , "Model­lversuche im Windkanal bur Bemusing von Brucken gegen die Gefahr winder­regter Schingungen," Der Stahlbau, Heft J 2, 1967.

16. Pirner, M. , "Stress-Ribbon Pedestrian Bridge Spanning 252 m," Symposium on Straight Crossings '94, Alesund, Norway, June 1994.

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