Puente del Campo Volantin (Campo Volantin Bridge)

Model Analysis:

The bridgeʼs secondary name is “Zubizuri” which in the basque language means “white bridge”, a tied arch footbridge designed across the Nervion River in Bilbao, Spain by Santiago Calatrava and offers pedestrians a convenient route from hotels to the nearby Bilbao Guggenheim Museum designed by Frank Ghery. The bridge start being build in 1990 and has ben finished in 1997.

As the designer remark the bridge is famous for itʼs graceful curving glass-decked foot dock. Not as the last like in other designs by Santiago Calatrava, an apparent disequilibrium or rather sad, a sense of frozen movement is heightened by the lightness of the structure.

The bridge design consists of an inclined structural steel arch linking two platforms, with access ramps and stairways on both banks. The curved steel bridge deck is suspended by steel cables.

Even if the bridge have a remarkable architectural presence the usability isnʼt really remarkable. The bridge it is locally infamous for the glass bricks set into its floor, which can become slippery in the wet climate of the city. The original design connects the bridge on the left bank to the Uribitarte dock and not to the higher street Alameda Mazarredo. Local authorities temporarily installed a further scaffolding footway joining the bridge and Mazarredo street, but removed it under protests from Calatrava. From 2006 until now there are many legal discussions between Santiago Calatrava and the local authorities due to many slips and falls of bridge users and the cost of replacing broken glass tiles reached 6,000 euros in the last year and 250,000 euros in ten years, according to a municipal report.

The main structural component is a steel arch, 75m long, 15m height with a 75m span.

Dealing with a inclined parabolic tied arch pedestrian bridge which utilizes steel in itʼs main component, we made our case study model at the scale of 1:750 and we decide to chose the following materials:

Component Material Youngʼs Modulus,E in KN/mm2

Remarks

Main Structure [Tie Beam]

Steel rod(∅ 21mm)

200 These steel rods were selected to imitate strength and deflection properties of the real bridge.

Parabolic Arch PVC pipe reinforced with Al. rod (∅12mm)

80 The decision to choose PVC pipe is because of its flexibility to be bended. To maintain the bridgeʼs Youngʼs Modulus, aluminum rods were inserted into the hollow PVC pipes as reinforcement.

T-Section Beams Sections of steel plates

200 These steel plates were selected to imitate strength and deflection properties of the real bridge.

Suspended Steel Cables

Nylon string (8 lbs. load carrying capacity)

15 Nylon strings have the springy property that may imitate the real movement and deflection on the bridge when load is imposed.

Glass decking Not shown Not calculated The glass decking (foot path) is not shown because it is a non-structural component.

We pick our materials really carefully and from these selections we assumed that our test model could imitate the real bridgeʼs strength and deflection.

After intense internet research we manage to find some relevant informations and dimensions of the real bridge and we start making the first model of the bridge, the one at the 1:750 scale.

Below we present the drawings which we made from the gathered information, to start designing our model.

PLAN - using 1:750 scale measured by ratio, but BASED on image DWG measures, its estimate to be maybe a 1:800 scale DWG

SECTION - 1:1250 DWG scale, a close-estimated diagramz

From these series of drawings, we made the first scale model of the bridge, scale 1:750.

The timber frame and base for the scale model was constructed to make the load testing easier. They do not hold any structural significance to the scale model.

We also built a blow up model at the scale of 1:250, like a detail or a section of the mid point section of the model, which allowed us to analyze the bridgeʼs strength properties in the middle, where actually all seems to be very well balanced.

The conclusion was that the middle of the bridge was perfectly balanced.

Having further researches on the entire model our only concern remained the spinning force which exist on the entire bridge, the entire bridge being very well equilibrated it self, but the way of how it is anchored that donʼt allow the entire structure to spin around remained the only mystery. The most important points for this problem are the joints from the ends of the bridge.

We supposed that the joints are welded or casted and have a fix plate inside, which was almost true.

Indeed, there is a part which keep still the principal beam and stop it from spinning. We also find this in the original technical drawings, made by Santiago Calatrava.

This detail, together with the ∅1m main steel beam stop the entire bridge from spinning.

This is why to avoid excessive rotation of the model bridge, the main beam was screwed (fix joint) to the timber base.

Model testing:All the gathered informations and what we observed from the previous test of the second model we applied on the principal model.

First we load the model with 2,5kg (left) and 5kg (right)

Second we load the model with 8kg (left) and 11kg (right)

Third we load the model with 15kg (left) and 20kg (right)

Fourth we load the model with 27kg (left) and 30kg (right)

In the end even if we loaded the model that it starts deforming, we add more weight and charged the model with 35kg. The model didnʼt broke, it just deform really strong.

As a charging parts we used scrap batteries as can be see.

From the above constructed models and material selection analysis, we decided to consider our bridge still stand by imposing 15 kg load. This test is calculated by using the following formula:

W EL2

We decided to test the scale modelʼs strength and deflection properties since our selection of materials are mostly having the same Youngʼs Modulus to the real bridge.

Area on plan = 0.4m x 0.75m = 0.3m2

Real bridge load carrying capacity = Live Load = 15 kN/m2

Dead Load = 15 kn/m2

Total Load = 30 kN/m2

Area on Plan x Total Load = 0.3m2 x 30 kN/m2 = 9 kN

From this calculation, it is expected that our scale model would have the strength to take a total load of 9 kN.

Group 6*Agnes YitHafiz AmirrolHeng Yeen SitOliviu Lugojan-GhenciuWen Ying Teh(*alphabetical order)