NAUE GmbH & Co.KG

Secutex sandcontainers save Bridge Cãteasca case study

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Courtesy of NAUE GmbH & Co.KG

As a result of the extreme rainfalls that occurred in Romania during the year 2005, many rivers had a significantly increase in water flow. One immediate consequence was that almost all the important rivers caused heavy floods with severe damage to civil structures and infrastructure. Another consequence with long term effects was that the increased water flows created high flows and erosion of the river banks and bed especially around structures built in water. Due to the high speed of the water, the precipitation of the solid particles could not take place, which generally prevented scouring. One example with extreme consequences is the big bridge in Mãrãcineni, over the river Buzãu, in the South Eastern part of Romania, that connects the historical provinces Muntenia and Moldavia. One pile of the bridge was eroded to the foundation level due to a water flow of more than 1.900 m³/s (typical average flow < 100 m³/s). Once the foundation was completely washed free, the pile collapsed, causing the bridge to collapse as well. The same situation appeared on a bridge on the river Arges, a main urtery to the A1 motorway. In the vicinity of the bridge, the terrain is consisting of silty clays that are prone to erosion. Two piles of the bridge, with foundations on 17 m deep pillars, were heavily eroded to the level of 15 m. The bridge became unstable and immediate measures were required in order to save it from collapsing. The regional administration of the Romanian Waters decided on immediate intervention, taking two technical possibilities into consideration: the bridge piles around the foundation needed immediate protection two breakwaters are constructed downstream of the bridge in order to decrease the water flow and allow the precipitation of solid particles. Comparing both solutions, the decision was made for the downstream breakwater since there was no stone available nearby. The Regional Water Administration decided to use Secutex type 'E' sandbags (1.45 m x 2.38 m for 1 m³), filled up with locally available soil. The sandbags had several advantages than the stone solution. First of all they are extremely flexible and therefore adjust perfectly to the subgrade contours. Additionally they are very robust and easily survive tough site conditions. Approximately 2,500 Secutex 'E' sandbags were filled with an excavator and local soil. After the filling process the bags were closed with a special portable sewing machine and a special robust sewed stitch. This way 300 bags were made per day with one sewing machine and one operator, and the bags were manoeuvred with a crane with lifting straps attached. After 4 months the engineers checked the installed sandbag protection and found out that sediments settled for more than one metre, increasing the stability of the bridge piles.

Year of construction: 2005 - 2006
City / Country: Romania
Installed products:
Secutex sandcontainers, type E 2,500sqm

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