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The expansion joints consist of structural openings designed to support the movement in a controlled way and, consequently, prevent any damage to the internal and external finishes of the bridge structure.The expansion joints play a role of fundamental importance in safeguarding the durability of the bridge by allowing the relative movements between the structural elements (vertical movements), due to variation of the deformation state to the variation of the applied load, to shrinkage phenomena and thermal gradients, preserving the regularity of the road surface.
The project consisted in the installation of a crash cushion to protect a cusp on a ramp with expansion joint, located on the State Road 76 of the Val d’Esino, near the “Jesi Est” exit, which is one of the main road axes between the regions of Umbria and Marche.
Installing a restraint system close to an expansion joint always presents considerable criticalities, especially because it hinders the anchoring of the device to the ground to allow the movement of the ramp.
It is therefore not conceivable the standard solution that involves the use of a reinforced concrete slab, nor is it possible to anchor to the asphalt surface by epoxy resin.
Fig.2 shows the detail of the anchorage.
The Research and Development department has studied a specific solution.
As it is not possible to use the traditional installation methods, the possibility of constraining the device on a galvanized steel plate was chosen, the latter constrained only on a ramp.
In the project illustrated the plate was constrained only from the side of ramp B (Fig.1) to allow the joint to expand. The crash cushion chosen in the specific case, among those is the Leonidas 80P.
The galvanized steel plate is bound to Ramp B through the use of 15 bars threaded with epoxy resin. For the realization of this anchoring system, static and dynamic checks were carried out.
During these phases, it was possible to evaluate the effect induced by the mass of the crash cushion on the anchor plate system plus chemical anchors in terms of displacement, stress and load on the threaded bars.
As a numerical analysis, a crash test TC 4.2.80 (side impact with vehicle mass 1300kg) and a test TC 1.2.80 (frontal crash with vehicle mass 1300kg) were carried out.
The TC 4.2.80 crash test is required by EN1317 and is the most critical test in terms of stress of threaded bars.
The versatility of the solutions proposed by SMA enables the road designer to always have a restraint device suitable for the protection of the fixed obstacle.
SMA’s Research and Development Department constantly collaborates with customers in order to always guarantee the highest level of safety for motorists in compliance with the criteria of compliance with the expected standards.
The A32 Turin-Bardonecchia, also known as ” Frejus Motorway”, is perhaps the main road link between Italy and France, with great implications not only on society, but also on the economy (both as regards the exchange of goods and tourism).An important element of this infrastructure is the Prapontin tunnel, in the Bussoleno – East Susa section. This tunnel, 4.4 km long, was completed in 1994 as the last step before the final conclusion of the works that gave life to the A32.
In 2012, this essential cross-border communication route was affected by modernisation and safety work. SITAF, the operator of the A32, had, among other things, requested shock attenuators that would be a real protection for all the thousands of people who circulate every day on those roads.
This is one of the first supplies of shock attenuators made by SMA Road Safety.
The positions in which these attenuators were to be installed had two critical issues:
1.The niches in the tunnel had sharp edges that were very dangerous for wandering vehicles;
2.Next to the bypasses there were accesses to the service areas. Therefore, these passageways had to be maintained.
In addition, the niches where the attenuators were to be placed presented problems inherent in the available space, leading to problems for the construction of the foundation.
The alternative would have been the use of a lower class impact attenuator (from 80 to 50 km/h) with the consequence that the level of containment guaranteed on the road section would not have been in accordance with the speed of travel of the road.
Another topic concerns the warranty offered by the components of the device according to the context in which it is used. The device, in fact, had to comply with the safety standards for road tunnels.
The great effort of analysis and engineering research carried out has allowed us to manage the supply project for the Frejus Motorway tunnel without serious hitches, respecting all the needs derived from the context, and to deliver the work by the pre-established date.
Specifically, the product proposed by SMA, had the following characteristics:
The results obtained were really excellent, so much so that SITAF itself wanted to write to us to tell us how high the level of protection ensured by our attenuators was:
“We are impressed by the more than satisfactory behavior of the restraint device and its “manual operation”, with a complete “packaging” of the elements such as to significantly reduce the effects of the accident on the driver of the vehicle involved, who got off the car with his own legs after a significant impact.”
Security is for SMA the main purpose of all activity. The goal is to build solutions to save lives. And having such awards makes it even more clear how fundamental it is to continue to invest in research and in the creation of ad hoc projects that can respond to every type of need.
A road without security is never viable. Thanks also to the role of SMA it becomes instead a trusted interconnection module for many citizens and companies, also capable of uniting several countries and cultures, as in the case of the A32, a connection to Europe without risk for those who travel it.
Eurasia Tunnel represented one of the most monumental engineering and private mobility projects of recent years.
It is a 5.4 km double bridge-tunnel that connects the European and Asian parts of Istanbul with a route of 14.6 km. It crosses the Bosphorus under the seabed at a maximum depth of 106 meters. The unprecedented combination of multiple complexities has consistently kept technicians and operators in suspense. It was something new, never realized before.
The Turkish company Yapi Merkezi and the South Korean company SK E&C have formed a joint venture for the management and completion of this work.
Investments of billions of euros came from international institutions and banks.
Contractors have contacted SMA to request a proposal to supply the devices in and out of the tunnel.
They were then suggested to the customer which devices to use in the various critical points through the positioning in the plan and the supply of the complete device.
The client’s goal was to create a safe and avant-garde road tunnel that could in some way also respect aesthetic canons that recall modernity.
The tunnels are highly critical concerning safety, an element that requires a specific management method.
Every minimum road risk (accidents, malfunctions of a vehicle, possible fires) in a tunnel is greater: that’s why for the contractors of this project the safety issue had to be managed perfectly!
In this specific case, the impact Crash cushions had to be positioned near the singular points with a particular risk of impact and had to be installed without creating any hitches.
In fact, given the presence of obstacles on the construction site (electrical cables, expansion joints), it was necessary to create ad hoc solutions so that the work continued without difficulty.
Another critical issue was represented by the speed and costs of realization of the work, which, in other words, meant the consideration in the design analysis phase also of:
– transit time of materials;
– customs clearance times and costs;
– conditions in which the work is carried out (in this case at night), trying to make the best of the daily hours that SMA had available to complete its part in this work.
SMA proposed to the client different types of impact Crash cushions by positioning the devices in front of the obstacle to be protected and supplying them.
Impact Crash cushions were installed in tunnel niches, bypasses, and in front of toll stations.
Thanks to our engineering consulting service, we have provided ad hoc solutions in accordance with the configuration of the obstacle to be protected.
Crash cushions had to have specific characteristics:
This engineering and industrial work together was done taking into serious consideration the delivery time of the project.
SMA boasts a 99.2% accuracy on delivery times, and, especially in a monumental work like this, respecting the agreements became essential.
We have therefore managed to bring home a result that has fully satisfied us, putting a bit of Pride and Italian ingenuity in a work of international importance.
We have learned a lot, and we now have a wealth of knowledge and experience that allows us to face any project with solidity. In fact, it is in such an unprecedented context that we have been able to put our skills to good use, making the SMA group grow even more.
Once the tunnel was completed we had the honor of attending the inauguration ceremony and receiving from the Turkish authorities a gift that we will remember forever.
At the presentation of this mammoth work, the collection of commemorative stamps for the birth of the Eurasia tunnel was delivered to us and all our colleagues. We were incredibly surprised to see that one of our Crash cushions was portrayed on one of these stamps.
For SMA it was an unprecedented recognition, which gave even more light to the whole team of experts who make our team so performing.
SMA Road Safety designs and develops crash barriers that provides maximum containment, great performances and minimal size on the road.
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