S&p Clever Reinforcement Company Ag

Re-Fer Ag

Empa

Eidgenoessische Materialpruefungs- Und Forschungsanstalt Empa

Eidgenossische Materialprufungs-Und Forschungsanstalt Empa

Eidg. Materialprufungs- Und Forschungsanstalt Empa

Masoud Motavalli

Christoph Czaderski

Christian Leinenbach

Rolf Bronnimann

Benedikt Weber

Niloufar Moshiri

Wookijn Lee

Rolf Broennimann

Martin Hüppi

Davood Mostofinejad

Julien Michels

Moslem Shahverdi

Wookjin Lee

Elyas Ghafoori

Ardalan Hosseini

Rolf Brönnimann

Martin Huppi

According to the method, at least one carbon fibre-reinforced polymer band is joined to the steel structure at the end regions thereof, capable of transferring tensile forces. Subsequently, at least one lifting element () disposed between the carbon fibre-reinforced polymer band () and the steel girder () to be reinforced in a region between these end anchorages (), is extended substantially perpendicular to the carbon fibre-reinforced polymer band (). So, a tensile force stress is generated between the end regions of the carbon fibre-reinforced polymer band (). Then, a steel girder treated in such a manner includes at least one carbon fibre-reinforced polymer band, which is each joined to the steel structure () at the end regions thereof, capable of transferring tensile forces. In the region between these end regions, a lifting element () is disposed between the carbon fibre-reinforced polymer band () and the steel girder () to be reinforced, by means of which the carbon fibre-reinforced polymer band () is subjected to tensile stress by lifting away from the steel girder (). The tensile force is transferred to the steel girder () via the anchoring elements ().

Method for pre-stressing a steel structure, and steel structure pre-stressed using said method

This method is suitable for the strengthening of concrete or timber structures by applying prestressed Carbon FRP or Glass FRP lamella. At least one groove is cut into the concrete or timber structure along the direction in which the concrete or timber structure is to be strengthened. The grooves are filled with epoxy resin and a layer of epoxy resin is put onto the entire section to be equipped with the CRFP or GFRP lamella. The lamella is prestressed and anchored at both ends. U-shaped brackets are then being put over the two end sections of the CFRP or GFRP lamella by inserting and submerging its both U-legs into holes filled with resin as well. These holding brackets are then tightly pressed onto the CFRP or GFRP lamella to prevent cracking or fracture of the concrete or timber and bending away of the extremities of the CFRP or GFRP lamella.

Method for strengthening concrete or timber structures using CFRP strips and concrete or timber structures strengthened by this method

The method includes a tension element, for example in the form of flat steel, that is placed on the structure or structural part and can be guided around a corner. The flat steel can also wrap as a band around the structure, in which the two ends of the flat steel are either connected to one another or are separately connected to the structure by the end anchors or intersect to produce a clamping connection. The flat steel contracts as a result of a subsequent active and controlled input of heat using a heating element and generates a permanent tensile stress and, correspondingly, a permanent prestress on the structure. The structure, as equipped, has at least one tension element as a shape memory alloy which extends along the outer side of the structure and is connected by one or more end anchors.

Method for producing prestressed structures and structural parts by means of SMA tension elements, and structure and structural part equipped therewith

The invention relates to a method according to which a profile consisting of a shape-memory alloy is placed into concrete, or a concrete to be reinforced is roughened on the outside, then profiles () consisting of a shape-memory alloy are fastened to the roughened outside () of the structure () and a cementitious matrix is applied to the roughened outside () to cover the profiles (). After the cementitious matrix has set, said profiles () produce a contraction force and thus a tension as a result of the input of heat. The mortar covering layer () thereby acts as a reinforcement layer owing to the interlocking of the mortar covering layer () with the roughened outside () of the structure (). The profiles () run in an outer mortar as a reinforcement layer () of the outside of a structure along the outside of the structure inside the mortar or reinforcement layer (). A structure can also be prepared for a prestress in the equipped mortar or reinforcement layer by the input of heat, in that electrical cables () are routed from the end regions thereof to the outside of the mortar or reinforcement layer () or the end regions of the electrical cables () are accessible by removing inserts ().

Method for building prestressed concrete structures by means of profiles consisting of a shape-memory alloy, and structure produced using said method

Growing community of inventors

Forch, Switzerland

Masoud Motavalli