Herbert A. Mang's research while affiliated with Tongji University and other places

Publications (381)

Article
As for the construction of a metro line, excavated stations usually serve as departure and receiving shafts of the shield tunneling machines, used for drilling of station-to-station tunnels. However, the shield tunneling machines may reach the stations before their excavation. In order to avoid stopping of tunneling to wait for the completion of th...
Article
Discontinuity layout optimization (DLO) is a relatively new upper bound limit analysis method. Compared to classic topology optimization methods, aimed at obtaining the optimum design of a structure by considering its self‐weight, building cost or bearing capacity, DLO optimizes the failure pattern of the structure under specific loading conditions...
Article
The purpose of this paper is to give a conditionally affirmative answer to the question posed in its title. The tool that enables such an answer is a mechanically objective arc-length in the form of a representative displacement of the structure. In this context, mechanical objectivity is defined as the independence of arbitrary model parameters, s...
Preprint
Full-text available
Discontinuity layout optimization (DLO) is a relatively new upper bound limit analysis method. Compared to classic topology optimization methods, aimed at obtaining the optimum design of a structure by considering its self-weight, building cost or bearing capacity, DLO optimizes the failure pattern of the structure under specific loading conditions...
Article
Full-text available
This review of the added value of multi-scale modeling of concrete is based on three representative examples. The first one is concerned with the analysis of experimental data, taken from four high-dynamic tests. The structural nature of the high-dynamic strength increase can be explained by using a multi-scale model. It accounts for the microstruc...
Article
Concrete beams carrying flat roofs are subjected to daily temperature cycles. Thermal eigenstrains at different scales of observation may be constrained or even prevented. This may apply to the entire beam and its support conditions, to the cross-sections of the beam, the microstructure of concrete, consisting of coarse aggregates embedded in a mor...
Article
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The vertices of two specific eigenvectors, obtained from a novel linear eigenvalue problem, describe two curves on the surface of an N -dimensional unit hypersphere. N denotes the number of degrees of freedom in the framework of structural analysis by the Finite Element Method. The radii of curvature of these two curves are 0 and 1. They correlate...
Article
Steel plate – concrete composite structure (SPCCS) was recently proposed to strengthen shield tunnels. The steel plate serves as the strengthening material. A combination of connectors and steel-fiber reinforced concrete is employed to establish the bond between the strengthening material and the tunnel lining. A full-scale test was conducted to in...
Article
Full-text available
The dissipated strain energy, representing a monotonically increasing state variable in nonlinear fracture mechanics, can be used to develop an arc-length constraint equation for tracking the energy dissipation path instead of the elastic unloading path of the response of a structure. This was the motivation for the development of a dissipation-bas...
Article
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Serviceability limit states (SLS) of segmental circular tunnel rings, subjected to symmetric loading, may experience asymmetric deformations. This is investigated herein, based on real-scale experiments and structural analysis. Single segmental rings, consisting of six tubbings and six joints, were subjected to 24 point loads, simulating ground pre...
Article
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Input of sinusoidal excitation with specified frequency is an optimal way to capture the mechanism of soil-tunnel interaction. Focusing on the relationship between the frequency of input sinusoidal motions and the dynamic response of a system, this study carried out a series of shaking table tests on both a free-field model and soil–tunnel model in...
Article
Exploitation of large underground space calls for innovative structures and construction methods. In this paper, a combined precast and in-situ-cast method for construction of large-span underground vaults is proposed. It was applied to an engineering example in the form of the vault of the Wuzhong Road Metro Station in Shanghai. This vault consist...
Chapter
This contribution deals with an assessment of the added value resulting from the use of a multiscale model of concrete as the basis for structural analysis of a segmental tunnel ring. The assessment rests on the comparison of a triad of results. They are obtained from a real-scale test of a segmental tunnel ring, from conventional structural analys...
Article
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...
Article
Full-text available
Purpose Transfer relations represent analytical solutions of the linear theory of circular arches, relating each one of the kinematic and static variables at an arbitrary cross-section to the kinematic and static variables at the initial cross-section. The purpose of this paper is to demonstrate the significance of the transfer relations for struct...
Article
The double deck system of road tunnel is of large cross-section. To investigate its characteristics under dynamic action large-scale shaking table tests are performed. Through comparison the seismic performance between a double deck tunnel model and a simple tunnel model, the effects of interior structure on the seismic performance of the segmental...
Preprint
Full-text available
Dissipated energy, representing a monotonically increasing state variable in nonlinear fracture mechanics, can be used as a restraint for tracing the dissipation instead of the elastic unloading path of the structure response. In this work, in contrast to other energy-based approaches that use internal energy and the work done by the external loads...
Article
Full-text available
In this paper, the significance of application-oriented fundamental research on concrete and reinforced concrete structures for progress regarding practical applications to structural design is addressed based on four examples. They were treated in a joint research project of Vienna University of Technology and Tongji University. The first topic re...
Article
Full-text available
The strength of specimens made of cementitious materials increases with increasing loading rate. Herein, the model of Fischer et al. (CCR 58, 2014, 186–200) is revisited in the context of high-dynamic compression and extended to high-dynamic tension. The model is based on the assumptions (i) that cracking will start if the quasi-static material str...
Article
Full-text available
Following the so‐called Cracking Elements Method (CEM), recently presented in [1,2], we propose a novel Galerkin‐based numerical approach for simulating quasi‐brittle fracture, named Global Cracking Elements Method (GCEM). For this purpose the formulation of the original CEM is reorganized. The new approach is embedded in the standard framework of...
Article
In this paper, the influence of torsional warping of the cross-sections of thin-walled twisted Functionally Graded Material (FGM) beams on their elastostatic behavior is investigated. The material properties are assumed to vary longitudinally. The variation is described by a polynomial. Secondary deformations, resulting from the angle of twist, are...
Article
Concrete hinges are monolithic necks in reinforced concrete structures. The serviceability limit states addressed herein refer to the open question how to limit tolerable relative rotations as a function of the compressive normal force transmitted across the neck. Analytical formulae are derived in the framework of the Bernoulli-Euler hypothesis an...
Article
Full-text available
Climate changes result in an increase of extreme weather events. Concrete pavements e.g. may be subjected more frequently to hail showers, following significant solar heating of their top surface. This scenario is studied by means of multiscale thermoelastic analysis. The semi-analytical solution of the heat conduction problem provides access to th...
Article
Structural defects of existing segmental tunnel linings call for strengthening techniques. This was the motivation for conducting real-scale bearing-capacity tests and computational analysis of strengthened segments by means of a steel-concrete composite (SCC). Two load cases were considered: (i) a sagging moment, resulting in intrados and extrados...
Preprint
Following the so-called Cracking Elements Method (CEM), recently presented in \cite{Yiming:14,Yiming:16}, we propose a novel Galerkin-based numerical approach for simulating quasi-brittle fracture, named Global Cracking Elements Method (GCEM). For this purpose the formulation of the original CEM is reorganized. The new approach is embedded in the s...
Article
Full-text available
When subjected to fire loading, shallow tunnels may experience loss of stability. This may result in large deformations and ultimately in local collapse of such structures. High temperature has a great negative influence on tunnels, not only because of thermal‐induced mechanical degradation of the heated lining but also because of thermal spalling...
Article
Full-text available
A nonlinear hybrid method is developed for multiscale analysis of a bearing‐capacity test of a real‐scale segmental tunnel ring subjected to point loads. The structural analysis consists of two parts. Part I refers to modeling of bending‐induced tensile cracking of the segments, resulting from the external loading. The segments are subdivided into...
Article
Full-text available
The Hong Kong-Zhuhai-Macao-Bridge (HZMB) is a traffic link consisting of two parts connected by an immersed tunnel. The structure may be subjected to moderate earthquakes. During such an exceptional load case, the joints between the 33 tunnel elements must remain water-tight. This was the motivation to perform 44 earthquake tests of 13 scaled eleme...
Article
Fire disasters occurring in underground structures generally result in severe damage. In order to investigate the fire performance of typical underground structures, a large-scale fire test on a three-span frame structure was carried out. The tested model was loaded both by vertical and horizontal earth pressures. The applied temperature history, r...
Article
Full-text available
The local behavior of segment-to-segment interfaces has a significant influence on the overall structural behavior of segmental tunnel rings subjected to ground pressure. This is quantified by means of structural simulations, combining analytical solutions of the linear theory of slender circular arches with time-dependent and nonlinear interface m...
Article
In this paper, the influence of torsional warping of thin-walled cross-sections of twisted Functionally Graded Material (FGM) beams with a longitudinal polynomial variation of the material properties on their eigenvibrations is investigated, considering the secondary deformations due to the angle of twist. The transfer relations needed for the tran...
Article
Full-text available
A 1:4 scaled fire test of a segment of a subway station is analyzed by means of three-dimensional Finite Element simulations. The first 30 min of the test are considered to be representative of a moderate fire. Numerical sensitivity analyses are performed. As regards the thermal boundary conditions, a spatially uniform surface temperature history a...
Article
Full-text available
Quasi-instantaneous thermal expansion of cement pastes is governed by the relative humidity (RH) within their air-filled pores and by the decrease/increase of this internal RH resulting from a temperature decrease/increase. The latter effect is traced back to quasi-instantaneous water uptake/release by cement hydrates, using microporomechanics and...
Article
Large deformations of shield tunnels may be the consequence of a long period of operation or of nearby pit construction. To reduce them, a novel strengthening method was recently proposed. It makes use of epoxy-bonded filament wound profiles (FWP). Full-scale tests were performed to prove the effectiveness of this method. The present paper contains...
Article
Full-text available
This paper contains an assessment of the added value of multiscale material models for concrete in the context of macroscopic structural analysis of (steel-reinforced) concrete structures. Two examples are discussed. They are inspired by the possibility of car accidents inside the immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge (HZMB). The fir...
Article
Full-text available
Transfer relations, representing analytical solutions of the linear theory of slender circular arches, have facilitated structural analysis of segmented tunnel linings. This is the motivation to apply such relations to two examples of circular arch bridges in which the bridge deck is held from the arch by equally spaced hangers. First, the number o...
Conference Paper
Structural analysis of segmented tunnel rings is challenging, because displacement discontinuities and relative rotation angles develop at segment-to-segment interfaces. To meet this challenge, a hybrid method was recently developed by Zhang et al. (2017). It uses the known external loading and measured interfacial discontinuities as input for stru...
Article
Full-text available
Existing design guidelines for concrete hinges are focusing on serviceability limit states. Lack of knowledge about ultimate limit states was the motivation for this work. Experimental data are taken from a testing series on reinforced concrete hinges subjected to eccentric compression up to their bearing capacity. These tests are simulated using t...
Chapter
Reinforced concrete hinges, subjected to eccentric compression, are failing in a ductile fashion (Schlappal et al. 2017). Three-dimensional Finite Element simulations are prime candidates for a more detailed analysis of this interesting structural behavior. Such nonlinear simulations, however, typically require pocedures for updating of the underly...
Book
Das Buch enthält eine umfassende Einführung in die traditionell als Festigkeitslehre bezeichnete Fachdisziplin Technische Mechanik deformierbarer fester Körper. Nach wesentlichen mathematischen Grundlagen dieses Fachgebietes werden die folgenden Teilgebiete behandelt: - Grundlagen der Elastizitätstheorie - Prinzipien der virtuellen Arbeiten - Energ...
Chapter
The title of this work represents a figurative counterpart of bridging the topographical gap between Hongkong and Macao. Presently under construction, the bridge that connects these two cities at opposite sides of the mouth of the Pearl River is interrupted by a submersed tunnel, which is the actual research object of this paper. By means of four d...
Chapter
This chapter contains a report on recent developments in the field of computational concrete mechanics, introducing the multiscale concept for simulation of cement-based materials and, in case of reinforced concrete Reinforced Concrete (RC), of the steel–concrete interaction. Within the framework of this concept, several scales of observation are c...
Article
Full-text available
Segmented tunnel rings exhibit load-induced interfacial dislocations. In order to facilitate structural analysis, a hybrid method is developed and applied to a real-scale test of a segmented tunnel ring. Point loads, imposed on the tested ring, and measured interfacial discontinuities serve as input for the analysis. Moreover, the method accounts f...
Conference Paper
The topical ambiguity of the term “bridging the gap” manifests itself in the 35.6 km long Hongkong-Zhuhai-Macao Bridge, presently under construction, and in multiscale analysis of a 5.7 km long tunnel below the bottom of the South China Sea, interrupting the bridge for shipping. On the one hand, a topographical gap is being bridged while, on the ot...
Conference Paper
This contribution deals with the behavior of segmented tunnel linings used in mechanized tunneling. Part I refers to the hybrid analysis of a real-scale test on a segmented tunnel ring. The structural analysis is hybrid in the sense that both (i) the prescribed external forces and (ii) the measured displacement/rotation discontinuities of the joint...
Article
In this paper, the influence of the variable axial force and of the Secondary Torsion-Moment Deformation-Effect (STMDE) on the deformations of beams due to torsional warping is investigated. The investigation is based on the second-order torsional warping theory of doubly symmetric beams with thin-walled open or closed cross-sections. The effect of...
Article
In order to develop an effective method to increase the load-bearing capacity of deformed segmental tunnel linings, full-scale tests concerning the ultimate bearing capacity of the linings, strengthened by steel plates, were conducted. The design of the tested linings and the loading scheme are described in this paper. In addition to the bearing ca...
Conference Paper
Quasi-instantaneous thermal expansion coefficients of mature cement pastes follow a non-symmetric bell-shaped function of the internal relative humidity. This is related to the experimentally proved fact that a temperature increase, ΔT, results in a quasi-instantaneous increase of the internal relative humidity, ΔRH. The present contribution establ...
Article
Full-text available
Splitting of the strain energy into its “non-membrane” and membrane percentage provides insight into the load-carrying mechanism of structures, subjected to proportional loading. It may be useful, for example, for sensitivity analysis of the initial postbuckling behavior of beams, arches, plates, and shells, and assemblies of such structures. The t...
Conference Paper
Multiscale structural “hybrid analysis” is proposed to analyze a real-scale exper- iment of a displacement-monitored segmented tunnel ring. Material modeling of concrete starts at the molecular scale of calcium-silicate-hydrates. Their elastic stiffness and fracture energy are upscaled to the material level of concrete, where the tensile strength o...
Conference Paper
Shield tunnels are environmentally friendly and mechanically effective. Shield-driven tunneling has been used extensively for more than 50 years. Large structural deformations may occur if the tunnel is subjected to unfavorable loading conditions concerning the underground soil. As a remedy, an efficient strengthening method was proposed. It is bas...