Civil Engineer Zaher Albasiouni Almasri

3rd year Civil Engineering Project

SAO PAULO’S OCTAVIO FRIAS DE OLIVEIRA BRIDGE

(this project includes a scaled wooden model, a 3D Autocad model, a general powerpoint presentation, and a detailed pdf file)

I - Introduction:

The bridge Octavio Frias De Oliveira is a unique reinforced concrete, cable-stayed highway bridge consisting of two separate curved bridge decks with total span of 290m each. It is situated in the heart of Sao Paulo, Brazil, and provides an important road connection aimed at reducing congestion in the city.

II - Transportation Study:

On July 6, 2007, a record 201 kilometers (125 miles) of roads were congested in São Paulo, Brazil, up from the daily average of 164 km (101 miles). With a population of 19 million , a rapid growth in the number vehicles (10% a year) and the lack of long term planning, São Paulo suffers from terrible air quality, numerous traffic deaths and injuries, and millions of hours of lost productivity where car drivers and public transport users alike sit in monumental traffic jams.

Octavio Frias de Oliveira Bridge is a part of this reconstruction process aiming at relieving traffic.
It acts as the junction between two perpendicular roads.
Being curved, it allows a smooth junction while achieving the necessary spans over the river.
It is able to receive up to four thousand vehicles per hour in each lane.

III - Analysis Study:

The corresponding cable diameter is 91.18 mm
the actual cables used on the bridge are 100 mm diameter (for safety).

Where:

V: is the vertical load exerted by the deck on the two opposite Cables.

L: is the distance between two consecutive cables (7.3m).
P: is the axial load in the cable of maximum inclination.
Ø: is the angle of the cable where the inclination is maximum with the deck (37.8 Degree).
A: is the cross sectional area of the cable.

IV - Additional Information:

The bridge Octavio Frias has huge amounts of character. Its unique design is impressive; the idea of creating a twin cable stayed structure with one mast was never previously done before.

It causes people to ask themselves how it works; how the separate decks balance each other and how the loads are shared through the tower, and whether in actual fact it acts more like two separate bridges than one or if each deck relies on the other for support.

Cable stayed bridges are best suited for medium span, low-level river crossings such as that required by the bridge Octavio Frias de Oliveira. They are also elegant and relatively cheap and simple compared to other forms of bridge construction.

      Considering the requirement for a bridge deck with such a tight curvature, most bridge types are ruled out; such as suspension, stress ribbon and cantilever. An arch bridge was also not possible due to poor ground conditions. For this reason, a cable stayed bridge was simply the only choice.

      Two smaller, straight decked cable stayed bridges were considered during the design process, however this design was abandoned possibly because it looked awkward, and because it did not provide a smooth junction for traffic without requiring land space adjacent to the river for the curved slip roads.

      The solution was to form an X out of 2 towers, each dedicated predominantly to each of the decks, however gaining stability from a connection where they cross. Each tower is inclined away from the curved deck it is supporting. This ensures that forces in the tower and the decks are mostly axial with minimal bending.

V - Bridge Data:

Height of mast: 138m

Top width of mast: 35.3 m

Bottom width of mast: 76 m

Top thickness of mast: 9.5 m

Bottom thickness of mast: 18.5 m

Deck span: 290 m each

Deck width (carriageway): 10.5 m

Number of cables: 144 (500 tons of steel)

Concrete Volume (mast): 5500 cubic meters

Construction cost: 184 million $

Construction time: 24 months

VI - Bridge pictures: