DSpace-CRIS at TU Wienhttps://repositum.tuwien.atThe reposiTUm digital repository system captures, stores, indexes, preserves, and distributes digital research material.Tue, 26 Jan 2021 08:59:14 GMT2021-01-26T08:59:14Z5031Ultimate limits of reinforced concrete hingeshttp://hdl.handle.net/20.500.12708/15566Title: Ultimate limits of reinforced concrete hinges
Authors: Schlappal, Thomas; Kalliauer, Johannes; Vill, Markus; Mang, Herbert; Eberhardsteiner, Josef; Pichler, Bernhard
Abstract: This work is a further development of its predecessor, the topic of which was verification of serviceability limit states of reinforced concrete hinges. Herein, the same conceptual approach is used to derive analytical formulae, supporting verification of ultimate limit states. These formulae limit tolerable relative rotations as a function of the compressie normal force transmitted across the neck. The mechanical model is based on the Bernoulli-Euler hypothesis and on linear-elastic and ideally-plastic stress-strain relationships for both concrete in compression and steel in tension. The usefulness of the derived formulae and the corresponding dimensionless design dia-grams is assessed by means of experimental data from structural testing of reinforced concrete hinges, taken from the literature. This way, it is shown that the proposed mechanical model is suitable for describing ultimate limit states. Corresponding design recommendations are elaborated and exemplarily applied to verification of ultimate limit states of the reinforced concrete hinges of a recently built integral bridge. Since the reinforcement is explicitly accounted for, the tolerable relative rotations are larger than those according to existing guidelines. It is included that bending-induced tensile macrocracking beyond one half of the smallest cross-section of the neck is acceptable, because the tensile forces carried by the reinforcement ensure the required position stability of the hinges.
Tue, 01 Dec 2020 00:00:00 GMThttp://hdl.handle.net/20.500.12708/155662020-12-01T00:00:00ZTransfer relations: useful basisfor computer-aided engineeringof circular arch structureshttp://hdl.handle.net/20.500.12708/16125Title: Transfer relations: useful basisfor computer-aided engineeringof circular arch structures
Authors: Zhang, Jiaolong; Liu, Xian; Yuan, Yong; Mang, Herbert; Pichler, Bernhard
Abstract: Purpose–Transfer relations represent analytical solutions of the linear theory of circular arches, relatingeach one of the kinematic and static variables at an arbitrary cross-section to the kinematic and staticvariables at the initial cross-section. The purpose of this paper is to demonstrate the significance of thetransfer relations for structural analysis by means of three examples taken from civil engineering.Design/methodology/approach–Thefirst example refers to an arch bridge, the second one to the vaultof a metro station and the third one to a real-scale test of a segmental tunnel ring.Findings–The main conclusions drawn from these three examples are as follows: increasing the number ofhangers/columns of the investigated arch bridge entails a reduction of the maximum bending moment of thearch, allowing it to approach, as much as possible, the desired thrust-line behavior; compared tothe conventionalin situcast method, a combined precast andin situcast method results in a decrease of themaximum bending moment of an element of the vault of the studied underground station by 46%; and thelocal behavior of the joints governs both the structural convergences and the bearing capacity of the testedsegmental tunnel ring
Fri, 30 Oct 2020 00:00:00 GMThttp://hdl.handle.net/20.500.12708/161252020-10-30T00:00:00ZHigh-dynamic strengthening of cementitious materials subjected to uniaxial compressionhttp://hdl.handle.net/20.500.12708/849Title: High-dynamic strengthening of cementitious materials subjected to uniaxial compression
Authors: Binder, Eva; Mang, Herbert; Yuan, Yong; Pichler, Bernhard
Abstract: Infrastructures made of reinforced concrete such as e.g. tunnels and bridges, must withstand exceptional loads, caused by earthquakes, car impacts, accidential blast loads, etc. The latter two belong to the high-dynamic loading regime where strain rates are typically larger than 1/s. In this regime, the strength of concrete specimens increases significantly with increasing loading rate. The reason for this strengthing effect is still debated. This provides the motivation for the present contribution which is devoted to the analysis of high-dynamic compression tests on cement pastes, mortars, and concretes. An elasto-brittle model for high-dynamic strengthening is employed, which was proposed by Fischer et al. (2014) and extended towards consideration of the scatter of the quasi-static strength values by Binder et al. (2017). The aim of the present contribution is twofold. At first, the quantitative assessment of the predictive capabilities of the described model is extended towards consideration of experimental data from Hao & Hao (2013). Secondly, the question is tackled how to represent high-dynamic strength values of different materials (cement pastes, mortars, and concretes) in one diagram, such that a meaningful direct comparison becomes possible. The latter goal is achieved by comparing two independent measures of the increase of the compressive strain during the failure process of a specimen: the first one refers to the measured Dynamic strength Increase Factor (DIF), the quasi-static strength, and Young’s modulus and the second one to the the strain rate, the characteristic crack propagation length, and the crack propagation speed.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/20.500.12708/8492018-01-01T00:00:00Z