Concrete hinges are hinges produced out of concrete, with no or almost no steel in the hinge neck, which allows a rotation without a relevant bending moment. [1] This high rotations [2] [3] are resulting from controlled tensile cracks as well as creep. [4] [3] [1] Concrete hinges are mostly used in bridge engineering [1] as monolithic, simple, economic alternative to steel hinges, which would need regular maintenance. Concrete hinges are also used in tunnel engineering. [1] [3] A concrete hinge consist of the hinge neck, which has a reduced cross section and of the hinge heads, which have a strong reinforcement. [3] [1] [5]
Freyssinet [6] [7] invented the concrete hinges. [1] [3] Leonhardt introduced guidelines in the 1960s which are still used till the 2010s. [1] [3] Janßen introduced the application of concrete hinges in tunnel engineering. [8] [3] Gladwell developed another guideline for narrowing cross sections, which predicts a stiffer behaviour than the Leonhardt/Janßen-model [3] Marx and Schacht translated Leonhardts guidelines for the first time in the nowadays used semipropablistic safteyconcept. Schlappal, [3] Kalliauer [1] and coworkers introduced for the first time both limit caces (service-limit-states (SLS) and ultimate-limite-states (ULS)). Kaufmann, Markić und Bimschas did further studies on concrete hinges. [9]
Due to triaxial compression, strength in the neck region is much higher than for uniaxial compression, [4] because lateral expansion is restricted. [1] Eurocode 2 suggests for typical dimensions a compressive strength equal to about twice of the unixalial compressive strength. [1] Also the concrete hinge neck has no, or almost no reinforcement, [1] but the concrete hinge heads need a dense reinforcement cache, because of tensile splitting. [10] [9]
Concrete hinges are hinges produced out of concrete, with no or almost no steel in the hinge neck, which allows a rotation without a relevant bending moment. [1] This high rotations [2] [3] are resulting from controlled tensile cracks as well as creep. [4] [3] [1] Concrete hinges are mostly used in bridge engineering [1] as monolithic, simple, economic alternative to steel hinges, which would need regular maintenance. Concrete hinges are also used in tunnel engineering. [1] [3] A concrete hinge consist of the hinge neck, which has a reduced cross section and of the hinge heads, which have a strong reinforcement. [3] [1] [5]
Freyssinet [6] [7] invented the concrete hinges. [1] [3] Leonhardt introduced guidelines in the 1960s which are still used till the 2010s. [1] [3] Janßen introduced the application of concrete hinges in tunnel engineering. [8] [3] Gladwell developed another guideline for narrowing cross sections, which predicts a stiffer behaviour than the Leonhardt/Janßen-model [3] Marx and Schacht translated Leonhardts guidelines for the first time in the nowadays used semipropablistic safteyconcept. Schlappal, [3] Kalliauer [1] and coworkers introduced for the first time both limit caces (service-limit-states (SLS) and ultimate-limite-states (ULS)). Kaufmann, Markić und Bimschas did further studies on concrete hinges. [9]
Due to triaxial compression, strength in the neck region is much higher than for uniaxial compression, [4] because lateral expansion is restricted. [1] Eurocode 2 suggests for typical dimensions a compressive strength equal to about twice of the unixalial compressive strength. [1] Also the concrete hinge neck has no, or almost no reinforcement, [1] but the concrete hinge heads need a dense reinforcement cache, because of tensile splitting. [10] [9]