Intervención en el Congreso de los Diputados

C.F. Ribeiro

Enescil Eng. Projetos Lda., São Paulo, Brazil

ABSTRACT: The Octavio Frias de Oliveira Cable-stayed Bridge is in the Rela Parque Roadway Complex and cross the Pinheiros River at the end of Jornalist Robert Marinho Avenue, in São Paulo, Brazil.

It is constituted by two curved ramps giving direct access between the Journalist Roberto Marinho Avenue and the expressway of the Nações Unidas Avenue. All such curved access lanes extend themselves and cross over the Luiz Carlos Berrini Avenue.

The way encountered to overcome all of interference was to create four foundation pile caps on which the towers start to rise to the pylon for the central support of the structure.

The pylon was started with 12 meter tall pillars, with a variable, rectangular section. Above this first level, two rectangular hollow cross section pillars begin to rise. After 11.4 meters of height, the extremities of these pillars are again connected longitudinally by a reinforced concrete platform, constituted by two beams and a slab. From the 23.4 meter two inclined towers rise, with a 1:3 ratio and a 57.6-meters height, the extremities of which converge towards the same point. These towers have a section with rectangular hollow cross section walls, with a width of 40 cm. At the 81 meter level, the extremities of these two towers meet, creating a cellular link with 9 meters of height (the knot of the "X").

The number of strands inside each stay-cable varies between 10 to 25. Due to the variable geometry of the complex, characterized by inclinated towers and overlapping decks, with a constant radius of curvature, an unique and innovative spatial arrangement was obtained.

The cable-stayed decks present a curvature in plan with 16- meter width and a constant radius, with 140-meter spans to cross the Nações Unidas Avenue and the CPTM trains, and 150-meter spans across the Pinheiros River.

The cable-stayed bridge over the Laranjeiras Channel, officially named "Anita Garibaldi Bridge", is localized in the city of Laguna, State of Santa Catarina (SC), and is included in the Duplication of the BR-101/South Highway project.

The work has an extension of 2.830 meters, being constituted by 49 approach spans with 50 meters in length and three cable-stayed spans each side span with 100-meter and a central, 200- meter span.

The approach spans of the bridge are built with typical, 50-meter spans, with 3.65-meter long segments, each of these segments with 80-tons. The precast concrete brackets supported by the box girder lower slabs allow the typical cross-section of the bridge to have a total width of 24.10 meters.

The foundations of the piers of those spans are built with concrete steel shearing piles, with a 2.50-meter diameter in the soil shaft and 2.30-meter diameter in the rock shaft.

The 49 approach spans are all simply supported spans, prestressed and made up by bonded segments. This system is only possible due to the technological resources of the BERD Company, where a launching gantry of the LG50 model with OPS (Organic Prestressing System) is used.

It is a cable-stayed section with a total length of 400 meters made up by two side spans of 100 meters and a 200-meter central span. The side spans have 24 segments and the central span has a total of 48 segments, all of which with a 3.30-meter length and a weight of 91 tons each. The key segment has a 2.0-meter length and is casted in place.

There is a single pylon at each pier, with a hollow, rectangular and variable cross-section in the first 16 meters of height. The pylons are built totally vertical without suffering any change in direction despite the fact that the deck is curved in plan.

1 INTRODUCTION

The Octavio Frias de Oliveira Cable-stayed Bridge is integrated to the process of the restructuring of the road system of the Municipality of Sao Paulo. It is in the Rela Parque Roadway Complex and cross the Pinheiros River at the end of Jornalist Robert Marinho Avenue.

It is constituted by two curved ramps giving direct access between the Journalist Roberto Marinho Avenue and the expressway of the Nações Unidas Avenue

The cable-stayed decks present a curvature in plan with a constant radius, with 140-meter spans to cross the Nacoes Unidas Avenue and the CPTM trains, and 150-meter spans across the Pinheiros River.

The geometry of the "X"-shaped tower makes this Bridge as a new post-card for the city of Sao Paulo.

The cable-stayed bridge over the Laranjeiras Channel, officially named "Anita Garibaldi Bridge", is localized in the city of Laguna, State of Santa Catarina (SC), and is included in the Duplication of the BR-101/South Highway project.

This bridge will allow to increase and modernize the highway, improving the connection between the productive hubs and the region’s seaside harbors. The investment, according to initial estimates, reaches R$ 600 millions and the bridge is built by three construction companies: Construbase, M. Martins and Camargo Correa.

The work has an extension of 2.830 meters, being constituted by 49 approach spans with 50 meters in length and three cable-stayed spans each side span with 100-meter and a central, 200- meter span. Of the 52 spans which constitute the bridge, only 11 approach spans are built over the ground, while the rest are built over the water.

2 THE REAL PARQUE COMPLEX

The Octavio Frias de Oliveira Cable-stayed Bridge, which is part of the Real Parque (Royal Park) Roadway Complex, is the 13th bridge crossing the Pinheiros River and it is integrated to the process of the restructuring of the road system of the Municipality of Sao Paulo, currently saturated by more than seven million vehicles.

With the objective of creating new access alternatives between the Pinheiros Riverbank Avenue and the Journalist Roberto Marinho Avenue, this engineering work aims at reducing traffic in the crossing of the latter with the Luiz Carlos Berrini Avenue, as well as the traffic on the Morumbi Bridge. Added to this localized improvement, this complex also aims at alleviating pressure on the Bandeirantes avenue, which will occur after the extension of the Journalist Roberto Marinho Avenue, all the way to the Imigrantes Highway.

Within this ambitious policy of improving local traffic, the roadway lay-out of this enterprise could not be simple. It is constituted by two curved ramps giving direct access between the Journalist Roberto Marinho Avenue and the expressway of the Nações Unidas Avenue. All such curved access lanes extend themselves and cross over the Luiz Carlos Berrini Avenue.

To make this roadway lay-out the most efficient as possible, there was the need to overlay the two curved, cable-stayed decks which cross the Pinheiros River, thus imposing the innovative geometry of the "X"-shaped tower. This new post-card for the city of Sao Paulo adds up to 2.910 linear meters of elevated roads, of which 580 meters of their overall extension are cable-stayed.

Figure 1. Roadway study.

Figure 2. Schematic plan of the foundation.

2.1 Foundations

To match the planned roadway lay-out, it was necessary to position the pylon of the bridge on the right riverbank of the Pinheiros River, where the Journalist Roberto Marinho Avenue begins. However, in this location there is a series of forms of interference which represent a severe hindrance. The underground concrete service gallery, which houses the CTEEP three transmission lines with 345 kVA, runs parallel to the right riverbank, as well as the railway line of the CPTM (Paulista Company of Metropolitan Trains) -. In addition to these two kinds of interference, there is also the adduction channel of the pumping station of the Aguas Estaiadas stream, buried exactly under the axis of the pylon.

The way encountered to overcome these forms of interference was to create four foundation pile caps on which the towers start to rise to the pylon for the central support of the structure.

Each one of these blocks is supported by 28 excavated piles, with a 130 cm. diameter (reduced to 120 cm. when embedded in rock) and 10 root-piles with a 41 cm. diameter (reduced to 31 cm. when embedded in rock).

Figure 3. Main Pier.

For this construction work 2.880 cubic meters of concrete and 184 tons of CA-50 steel were used.

In its cable-stayed portion, the foundations for side pier, facing the Journalist Roberto Marinho Avenue, were built with 11 excavated piles, with 110 cm. of diameter (reduced to 100 cm. when embedded in rock)..With regards to the side pier located on the left riverbank, due to the presence of transmission lines which made it impossible to use large-size equipment, 50 large root-piles were built, with a diameter of 41 cm. (reduced to 31 cm. when embedded in rock).

For the construction of the foundations of these piers, in each extremity, 490 cubic meters of concrete were consumed.

2.2 Main Piert

The pylon was started with 12 meter tall pillars, with a variable, rectangular section. In this position, the pillars are cross-linked transversally by a ribbed slab and longitudinally by a concrete prestressed platform constituted by two beams and one slab. From this platform the deck of the journalist Roberto Marinho Avenue, seeking the Pinheiros Riverbank Avenue, begins.

Above this first level, two rectangular hollow cross section pillars (walls with a 40 cm and a 60 cm width) begin to rise. After 11.4 meters of height, the extremities of these pillars are again connected longitudinally by a reinfored concrete platform, constituted by two beams and a slab. From this platform the deck of the Pinheiros Riverbank Avenue, in the direction of the Journalist Roberto Marinho Avenue, is born.

From the 23.4 meter (where the reference is the side of the block) two inclined towers rise, with a 1:3 ratio and a 57.6-meters height, the extremities of which converge towards the same point. These towers have a section with rectangular hollow cross section walls, with a width of 40 cm. At the 81 meter level, the extremities of these two towers meet, creating a cellular link with 9 meters of height (the knot of the "X").

From this point upwards, two other towers with an inclination ratio of 1:4.5 (this proportion was necessary to minimize the torsion effects in the pylon due to permanent loads) in a way that its extremities draw away, giving the "X"-shape to the pylon. In these 42 meter-long parts, the

Figure 4. Details of the central support.

anchoring devices of the stays are located. the walls of their rectangular hollow cross section are pre-stressed so as to assure that no traction tension may exist due to the horizontal component of the stays’ force. Lastly, a beam with a cellular section was created at the 107 meter level with the objective of blocking these towers, in order to reduce the flexion and torsion moments.

Above this part of the pylon, already at the 132-meter level, an architectural detail with 6-meter of height, is used to convey to the pylon a better aesthetics and lightness.

In short, to execute this 138-meter high pylon, 5.600 cubic meters of concrete and 1.220 tons of CA-50 steel, in addition to 63 tons of CP190-RB steel.

2.3 Side Piers

The side piers are constituted by massive pillars with a rectangular section and rounded-off corners, which support a cross-beam with the purpose of making a monolithic link between the pillar and the stayed deck, besides serving as a support for the pre-fabricated concrete girders of the approach spans ramp.

2.4 Stay-cables

The stay-cable corresponds to the system used in suspension bridges to transfer directly the active loads between the deck and the pylon.

Each stay-cable is constituted by a set of parallel strands. These strands, in turn, are formed by seven galvanized steel wires, helically distributed, protected by an individual HDPE (high-density polyethylene) sheath filled with wax.

In addition to the individual protection of the strand, there is also a HDPE tube, yellow in color, which wraps all the strands which make up the same stay-cables. The number of strands inside

Figure 5. Details of the side piers.

each stay-cable varies between 10 (stay-cables nearer to the pylon) to 25 (stay-cables nearer to the side piers).

Due to the variable geometry of the complex, characterized by inclinated towers and overlapping decks, with a constant radius of curvature, an unique and innovative spatial arrangement was obtained.

In the cable-stayed spans over the Pinheiros River, once the decks are positioned on the opposite side to the towers that support them, there is an interlacement of stay-cables that creates a special configuration in their geometric disposition which has not yet been verified in any other cable-stayed bridge in the world.

All the stay-cabling of this work consumed approximately 375 thousand meters of strands, equal to 462 tons of steel.

2.5 Deck

The cable-stayed decks present a curvature in plan with a constant radius (equal to 275.1 meters measured axially), with 140-meter spans to cross the Nacoes Unidas Avenue and the CPTM trains, and 150-meter spans across the Pinheiros River.

The 16- meter width of the deck is constituted by two 1.5-meter longitudinal girders (where the anchors of the stay-cables may be found), two 85 cm.-wide sidewalks, two 40 cm-wide concrete barrier and a 10.5-meter carriage way (on a 48 cm.- thick slab).

Built with the cantilever technique, the longitudinal structural members were prestressed with penpons positioned in its upper side to avoid excessive traction tensions during construction phases. Another prestressing operation during the deck’s construction was the one constituted by cables located near the inner edge of the deck, with the objective of overcoming the flexion moments in plan (horizontal plane), originated from the horizontal vectorial component of the force of the stay-cables, which does not align with the longitudinal axis of the deck.

A transversal prestressing of the slab was also carried out during the deck’s construction, so that the slab may support loading without cracking.

The only prestressing carried out after the conclusion of the deck’s construction refers to the continuity tendons, mostly distributed near the lower surface of the girders to assure that the section

Figure 6. View at top of the pylon.

Figure 7. Bridge deck.

Figure 8. Cross section of the deck.

should not be submitted to tensions greater than those stipulated by the Brazilian regulations, during the service phases, that is, under the action of mobile loadings.

There is no bearing support equipment on the site, and the connections between deck and pillars were made monolithically fixed).

For the construction of the 590-meter deck the following were used: 6.400 tons of concrete and 885 tons of CA-50 steel, as well as 420 tons of CP190-RB steel.

2.6 Engineering and Architecture

It is important to emphasize that this bridge complex was completely conceived by engineers, especially and initially by the professionals of ’Enescil Engenharia de Projetos Ltda’ and, later, by the teams of ‘ANTW Engenharia de Projetos Ltda’, ‘Antranig Muradian Ltda’, and ‘Geometrica Engenharia de Projetos Ltda’, who approved the calculations and confirmed the initial design of the work as feasible, functional, safe and economic for its site.

After the definition of the engineering solution for the work, the architectural office ‘Valente e Valente Arquitetos’ was responsible for complementing the design, softening contours, defining friezes, choosing the color of the stay-cables and the form of the guard-rail, amongst other activities. Shortly, the architecture and conception of the work, especially the "X"-shaped-pylon, was the exclusive work of the engineers. The architect’s team was responsible for the complementary, although important, task of beautifying and giving finishings to the work.

3 ANITA GARIBALDI BRIDGE

The cable-stayed bridge over the Laranjeiras Channel, officially named "Anita Garibaldi Bridge", is localized in the city of Laguna, State of Santa Catarina (SC), and is included in the Duplication of the BR-101/South Highway project.

With the current daily capacity limited to just 20 thousand vehicles, this work will allow to increase and modernize the highway, improving the connection between the productive hubs and the region’s seaside harbors, for the well-bring of the regional and national economies, as well as those of other Mercosul countries. The investment, according to initial estimates, reaches R$ 600 million and the bridge is built by three construction companies: Construbase, M. Martins and Camargo Correa.

The work has an extension of 2.830 meters, being constituted by 49 approach spans with 50 meters in length and three cable-stayed spans each side span with 100-meter and a central, 200-meter span. Of the 52 spans which constitute the bridge, only 11 approach spans are built over the ground, while the rest are built over the water.

3.1 Approach spans of the Bridge

The approach spans of the bridge are built with typical, 50-meter spans, with 3.65-meter long segments, each of these segments with 80-tons. The precast concrete brackets supported by the

Figure 9. Bridge location.

Figure 10. Longitudinal layout and plan of the Bridge.

box girder lower slabs allow the typical cross-section of the bridge to have a total width of 24.10 meters.

The foundations of the piers of this spans are built with concrete steel shearing piles, with a 2.50-meter diameter in the soil shaft and 2.30-meter diameter in the rock shaft.

The pillars in the approach spans form a continuity with the foundations, with their starting points located above the steel sheath and ending points in the corbels and cross-beams, where the plinths for the super-structure are located.

The 49 approach spans are all simply supported spans, prestressed and made up by bonded segments. This system is only possible due to the technological resources of the BERD Company, where an launching gantrie of the LG50 model with OPS (Organic Prestressing System) is used.

The construction of the spans using this truss had initially an estimated time-schedule of one week for the building of each span; however, during the course of construction, shorter periods of four to five days per span were achieved.

3.2 Construction sequence of the LG50 BERD truss 3.3 Images of the construction sequence of the Bridge

After the construction of the spans by means of the launching gantry (launching, bonding and prestressing of the segments), the launching of the precast concrete brackets by means of cranes was started on both sides of the deck, fixed to the box girder through high-resistance rods.

Figure 11. Cross section of the simply supported spans.

Figure 12. Support of box section at the simply supported spans.

Figure 13. 3D Model of the LG50 Launching Gantry by BERD.

Figure 14. Launching Gantry model LG50 - BERD.

Figure 15. LG50 Model launching gantry. Preparation for lifting the segments.

Figure 16. Lifting and suspension of the first 7 segments. Placing of the counterweight for the launching gantry.

The lateral slabs are constituted by precast plates supported by the precast concrete bracket and a thin concrete surface with a medium thickness of 14 centimeters, adding up to a 25-centimeter final slab. Since these slabs have an 7.55 meter width, a transversal-prestressing is used to guarantee the safety of the slabs and a firm linkage with the box girder.

Figure 17. Suspension, placing and bonding of the 7 remaining segments.

Figure 18. Placing and bonding of the first suspended segments. Launching of the gantry for the next span.