Our approvals and type approvals.
PORR Spezialtiefbau GmbH has a large number of its own general building inspectorate approvals. Every customer can rest assured that we can fulfil any construction task, no matter how special, thanks to our technical expertise.
![[Translate to English:] PORR Spezialtiefbau Stump Kontaktanker Z 34.11 224](/fileadmin/_processed_/6/5/csm_PORR_Spezialtiefbau_Stump-Kontaktanker_Z-34.11-224_d0b3cb7765.webp)
Soil nailing System PORR.
The temporary or permanent securing of steep slopes and excavations with soil and rock nails is a major focus of PORR's special civil engineering activities. We have significantly influenced and further developed these tried-and-tested construction methods, which have our own general building authority approvals, since their market launch.
The arrangement of tensile round rods, so-called nails, makes it possible to create a monolithic body in loose rock that safely absorbs the earth pressure forces that occur. GEWI steels are used as load-bearing elements, which are coated with a ribbed tube injected with a cement suspension as corrosion protection for long-term use.
Depending on the application, it is also possible to use cuttable tensile elements made of glass fibres, so-called GRP elements, or self-drilling nails for securing during tunnelling. The surfaces of the loose rock secured by soil or rock nails are then stabilised using a statically designed and reinforced shotcrete shell. Our engineers use state-of-the-art calculation methods to determine the optimum arrangement and dimensions of the stabilising elements to be used.
Jet grouting Stump Jetting.
PORR Spezialtiefbau GmbH was one of the first companies to hold a general building authority approval for the jet grouting method in Germany. The continuous further development of the individual components helps to ensure a high level of reliability in execution.
With the publication and introduction of DIN EN 12716:2019-03 "Execution of special civil engineering works - Jet grouting; German version EN 12716:2018" as a technical building regulation, the planning and execution of load-bearing elements using jet grouting or high-pressure injection is regulated (see MVV TB, No. 1.2.2.7). A general type approval is no longer required. The use of subsoil improvement methods is permitted by the building authorities and does not require a type approval. You can find out more about the building inspectorate framework on the website of the Deutsches Institut für Bautechnik.
The jet grouting method is used for
- Underpinning
- sealing slabs
- Section sealing
- Sealing blocks
- retrofitting foundations
- soil improvement
Permanent anchorStump-Duplex.
The patented Stump Duplex Anchor was the first permanent anchor to receive general technical approval in Germany and was the first permanent anchor to be exempted from the obligation for subsequent monitoring. For over 40 years, this permanent anchor system has been used as a permanent anchor for more than two years.
The Stump Duplex anchor is a pressure tube anchor in which the force is transferred into the grout body via the rear end of the grout body. A pressure tube, the so-called duplex tube, serves as the force transmission element. The anchor steel tension member is not connected to the grout body. As the grout body transfers the force from the anchor end into the ground via compressive forces, cracking in the grout body and a resulting reduction in force transmission between the grout body and the existing ground is not to be expected.
Rock strand anchorStump rock anchor.
The Stump rock anchor illustrates the development of anchoring technology for use in rock. Its application is generally limited to cases where the entire load-bearing length is embedded in the rock. Furthermore, it is also possible to install Stump rock anchors in alternative configurations, subject to the approval of a geotechnical expert.
Even in challenging soil and rock formations, specialised grouting techniques enable the use of heavy-duty anchors with high load-bearing capacity.
Milestones in further development.
A significant example of application is the uplift protection for the Eder dam. Here, 104 type 6–34 continuous-strand rock anchors with a working load of 4,500 kN were installed. The test loads amounted to up to 12,500 kN for anchor lengths between 68 and 73 m. The drilling of the boreholes had to be carried out carefully in the area of the dam and with the utmost precision throughout the entire site. At 0.5 per cent, the drilling deviations were still below the strict tolerance specification of 1 per cent drilling deviation.
To install the rock anchors, a core drill hole with a diameter of 146 mm was first drilled. This was subsequently reamed to 276 mm. A cement-based rock and masonry grouting process was used to improve the properties of the subsoil, particularly in the area where the forces are transmitted. This was verified by means of WD tests. The anchors were installed using a special deflection structure and a mobile crane to minimise the risk of damage to the anchor’s corrosion protection during installation.
A tensioning press, custom-built for this project, was used to tension the anchors. Ten of the 104 anchors were additionally fitted with load cells and fibre-optic sensors for monitoring. The anchor heads are designed in such a way that anchor force measurements can be carried out and the anchors retensioned if necessary.
Another example of application is the stabilisation of a large rock mass at the Kammereck cliff between St. Goar and Oberwesel. Here, 23 permanent rock anchors, each with a working load of 2,000 kN, were installed. The rock mass is situated above the B9 federal road and is traversed by a Deutsche Bahn tunnel. The permanent anchors, which are up to 40 m long, each consist of 23 individual strands and were arranged on two reinforced concrete crossbars. The working load was applied in stages. Meanwhile, the deformations of the rock mass were monitored using multi-point extensometers.
HLV pole PORR special civil engineering system.
HLV piles are pipes made of ductile cast iron, joined together from partial lengths to form the total pile length. The partial lengths are connected to each other via the pile's own ductile cast iron pile sockets or via special coupling elements and driven into the ground by pile drivers. The driving process creates a rigid, positive and non-positive connection. Depending on the soil conditions, a driving spike or driving shoe is used to drive the pile into the ground.
So-called ductile piles are used either grouted or ungrouted as compression and/or tension piles. They can also be installed vertically or inclined up to a depth of 55 metres.
They are available in the following specifications:
- Diameters of 118 and 170 mm
- Load transfer up to 1,400 kN
Stump compact anchorfor rock and soil.
Compact anchors, also known as grouted anchors, are used in a wide range of applications. One of the most common forms of application is the temporary securing of construction pits for less than two years.
Permanent anchors or permanent anchors, such as the strand compact anchor, have proven their suitability for anchoring tent roofs, bridges, slopes and retaining structures. However, this technology can also be used efficiently and economically for smaller projects. One example of this is the pylon bracing of the tent roof construction for the all-weather swimming pool in Velbert.
Compact anchors are also used in bridge construction, for example in the construction of the Kylltal bridge, where 58 anchors with a working load of 2,700 kN had to be installed on each side to transfer the forces from the cantilever construction. On one abutment side of the bridge, it was only possible to produce the anchors for the foundation to be anchored from a much lower working level than the later foundation. For this foundation work, it was necessary to extend this anchor by around 7 metres after production, as well as to form a coupling point, as is known from prestressed concrete. To ensure quality, the entire work at the coupling points was extensively monitored.
Stump strand pressure pipe anchorfor soil and rock.
Pressure tube anchors, such as the Stump strand pressure tube anchor, are so-called grouted anchors. The anchor force to be transferred into the subsoil is transferred from the steel tension member via a steel pressure tube from the anchor base to the grout body for introduction into the subsoil. The remaining space between the steel tension member and the pressure pipe is filled with a viscoplastic corrosion protection compound.
This anchor system combines the great flexibility of the strand load-bearing elements with optimum force transmission via the pressure pipe.
In addition, the Stump strand pressure pipe anchor is ideal for confined installation conditions.
Composite pile PORR special civil engineering system.
The PORR composite pile system can be used as a single-rod pile for compressive and tensile forces of up to 2,574 kN. The load-bearing element is a round steel bar with threaded ribs rolled onto both sides, which are arranged along the entire length. Coupling also makes it economically feasible to use the bonded pile for room heights.
The rolled-on threaded ribs are used for the friction-locked connection of anchor pieces and anchor nuts, for coupling individual pile sections using threaded sockets, as well as for improving the bonding effect to the surrounding cement stone in the force transmission area. The profiling of the load-bearing element enables exact fixing in the pile head area as well as any extension of the pile projection using approved connecting parts. Provided with corrosion protection in accordance with the associated general building inspectorate approval, the composite pile can also be used as a tension pile for load-bearing forces of up to 990 kN.
The design of the pile allows proper pile fabrication even at minimum installation heights of approx. 2 metres. When installing a post-injection system, it is also possible to specifically improve the existing soil in the force application area by means of post-grouting.