Not only for drain construction - Linear Shoring: Varied applications thanks to modularity

Inner-city Linear Shoring works on the same principle as overlapping large-area shoring, except that instead of the shoring panels running on the inside and outside, two overlapping piling elements are introduced into the shoring rails. An outstanding feature of Linear Shoring is that the individual components – panels, soldiers and roller frames – can be moved independently of one another. For installation, the shoring panels are driven vertically, chopping off the soil beneath.

In this way a frictional joint is established with the soil face. Linear Shoring soldiers and roller frames interact to create a stable system. Changes in the trench geometry familiar from other shoring systems are thus ruled out. Because the shoring remains parallel at all stages of construction, Linear Shoring is easy to use and does not jam. Another advantage is that, as a result of its high structural strength and the variety of its system components, there are practically no limits to its applications.

In addition to conventional drain construction projects, Linear Shoring is ideal for securing pits for the construction of bridge abutments, shafts, oil separators and detritus tanks, for launch pits and for the installation of underground tanks.

Technical advantages
The sliding rail shoring system consists of individual rails in which panels are guided vertically in an overlapping arrangement. The decisive factor is that opposite rails are connected not by articulated spreaders but by a rigid, width-adjustable roller unit that keeps the shoring modules the required distance apart.

The rigid roller frame ensures that the trench width remains the same at every stage of installation and extraction. This yields considerable advantages. Linear Shoring soldiers can be produced in (almost) any desired length.

Extension rails, which might hamper installation and extraction, are not necessary. For greater trench depths, a second roller unit can be employed at an advanced stage of construction. There are no spreaders impeding the excavator arm.

The twisting of rails about their own vertical axis is counteracted by the broad contact surface of the roller unit, which effectively distributes the loads with the aid of floating rollers. This design feature prevents the shoring panels from jamming in the rails. Since the shoring panels are pivoted in from the side, extremely long rail elements can be employed.

The design features of Linear Shoring enable the system to be used even in exceptionally deep trenches. Projects involving trench depths of about 10 to 11 m have already been accomplished with the system. Such achievements are out of the question with the large-area shoring systems conventionally used.

In addition, the ground outside the trench remains largely unaffected. Even if buildings are located in the immediate vicinity, settlement is minimal. At the same time, shoring performance is high owing to the ease with which the shoring modules are extracted. And this has a positive economic effect on the project.

Tailor-made solutions
With overlapping Linear Shoring, for instance, the customer can choose between module lengths of 2.25 m, 2.96 m, 3.40 m, 3.70 m, 4 m, 4.25 m and 5.25 m. The width can be extended from 90 cm in increments of 14 cm. Owing to this diversity of system components, it is possible, taking account of the anticipated static loading, to even secure trenches whose dimensions far exceed those of conventional drain construction projects. On such projects, a corner rail solution is adopted at the ends of the trench or panels are placed in front of the shoring.

If pipelines have to be fed in from the end of the trench, or if larger widths are involved, the E+S waling girder is employed. It is held in the profile of the Linear Shoring soldier. The lower girder is preassembled together with the components of the shoring system. During installation, the girder moves freely into its intended position. It can be adjusted in height at any time and is aligned flush with the end of the Linear Shoring system.

When the upper waling girder has been subsequently fitted from above, the piles can be inserted. Many clients and contractors are unaware of the versatility of this shoring system. Yet Linear Shoring has proven in many cases to be the most cost-effective and efficient solution in a wide range of civil engineering projects.

Creating room to manoeuvre
For instance, on the former site of the DuPont production plant in the immediate vicinity of the Bonn-Nord motorway intersection, Heitkamp Erd- und Strassenbau GmbH opted for a special shoring method to secure excavation work. In 4 m wide and in each case 20 m long trenches secured with Linear Shoring from Emunds+Staudinger, the soil was replaced section by section on the 500 m² site.

The installation of two superimposed Linear Shoring systems enabled the excavators to replace the contaminated soil in the dangerous area fringing the embankment of the A 565 motorway to a depth of 12 m. After controlled soil replacement and soil remediation at the Bonn-Tannenbusch site, the client, DuPont Performance Coatings GmbH & Co. KG, was able to hand over the site ready for occupation to its new owners.

Concrete walls poured against Linear Shoring
Building contractor E. Heitkamp GmbH, Boxberg branch, opted for a far from run-of-the-mill process for the pouring of the feed bunker for the new animal meal incineration plant at Boxberg power station. Shuttering and steelfixing work and the subsequent concreting of the structure were carried in the roughly 10 by 15 m pit secured by the Linear Shoring system from Emunds+Staudinger. The decision in favour of the flexible and efficient shoring system paid off for the contractor in many ways.

Firstly, the trouble-free and swift installation and extraction of the shoring enabled him to keep precisely to the strict time-frame. Furthermore, it was also possible to reduce the dimensions of the required pit to such an extent that the immediately adjacent double foundation slab for two silo towers could be poured at the same time.

XXL shoring project
The new section of the automatic goods transport system that Joos Strassen- und Tiefbau GmbH is constructing on behalf of Freiburg University Construction Department is about 220 m long. On its completion, the subterranean rectangular tunnel containing not only the goods transport system, but also various pipes, cables and drains will connect the central kitchen, casino and research building to the University Clinic's ring supply main. At several points of the goods transport system, special structures have to be engineered.

The construction work is being carried out in an open pit. So that the work can be performed in safety, the contractor is using the Linear Shoring system from Emunds+Staudinger. The pit at the lift stations, where the containers of the underground handling system will eventually be elevated into the building complexes above, has remarkable dimensions – a clear width of 8.6 m and a depth of over 8 m.

[At the end walls of the pit for the shaft structures on the site of the Freiburg University Construction Department, the E+S waling girder was employed. It is held in the profile of the Linear Shoring soldier. The lower girder is preassembled together with the components of the shoring system. During installation, the girder moves freely into its intended position. It can be adjusted in height at any time and is aligned flush with the end of the Linear Shoring system. When the upper waling girder has been subsequently fitted from above, the piles can be inserted.]

Monster tank installed in Erfurt
When the oversize tank arrived on the construction site in Erfurt's new Technology Centre, everything got moving swiftly. The two excavator operators of HERMANNS EHT-Bau GmbH took only twenty minutes to delicately lift the 12 metre long and 3 metre diameter plastic rainwater tank into the ready-dug pit.

The speed of this manoeuvre was made possible by the use of Linear Shoring from Emunds+Staudinger GmbH. After the fitting of external walings along the sides and ground-level bracing for the middle pairs of soldiers, the two middle roller units were removed from the pit comprising a total of four sections in order to create the necessary working space for lowering the tank.

City of Hamburg’s tough demands fully complied with
The soil rehabilitation project in Hamburg’s district of Wandsbek, carried out by Heinrich Weseloh Strassen- und Tiefbau GmbH on behalf of the City of Hamburg’s Urban Development and Environment Department, Site Rehabilitation Unit, involved excavating 15,000 m³ of soil.

In accordance with the client’s brief, the contractor secured the earth-moving work on the 2,355 m² site with a double sliding rail system. The overlapping Linear Shoring system from Emunds+Staudinger was employed. Equipped with reinforced extension bars, the high-performance trench shoring system satisfied all the client’s requirements in terms of the demanded excavation depth of over 8.5 m and type approval for soil pressures of at least 120 kN/m³. The fact that it was possible from the installation stage onwards to secure the trench with a single roller unit meant that the excavator had optimum room to manoeuvre during the extensive digging work.

These selected examples of applications show the varied uses and efficiency of Linear Shoring. The technical and economic expectations of shoring systems have risen constantly in the last few years. E+S has responded to these challenges and made practical refinements of the existing product range as well as launching new, innovative shoring systems and special solutions for special construction tasks.

Talks with our technical consultants are an outstanding opportunity for clients and contractors to obtain technically mature solutions for a variety of (drain construction) projects, customized for the specific site.

This article was first published in German, titled: "Linearverbau aus dem Baukasten: Flexibel im Einsatz und wirtschaftlich" in the German Fachmagazin tis, Heft 9/2005, S. 14-18, Giesel Verlag GmbH, Isernhagen. http://www.tis-online.info

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