Nonlinear Behavior of Reinforced Concrete Circular Tunnel under Seismic Motions in Clayey Soil

Tunnels are a critical component of our transportation infrastructure, and unexpected damage to a tunnel can significantly and adversely impact the functionality of a transportation network. Tunnel systems are vulnerable to potential threats of intentional and accidental blast events because of their relatively unrestricted public access. These events can lead to spalling and breach of the tunnel liner which, depending on the surrounding media, can result in local damage and progressive collapse of the tunnel. Current approaches for evaluating blast-induced damage to a tunnel liner either require significant computational effort or oversimplification such that accurate spatial distributions of damage cannot be obtained. This study presents an effective approach to predict and map the damage to a reinforced concrete liner of a roadway tunnel from various explosive threat sizes and tunnel geometries. A literature review of existing studies is conducted, and potential scenarios of blast events are examined with varying charge position and size. Rectangular, horseshoe, and circular tunnel geometries, each with the same traffic throughput, are evaluated. An efficient analytical approach to determine the spatial distribution of blast-induced spall and breach damage is presented and shows good agreement with numerical models analyzed in LS-DYNA. The proposed approach is then used to examine the relationship between increasing blast hazard intensity and the extent of spall and breach damage. Inflection points in this relationship can be used to identify hazard levels at which a progressive collapse evaluation would be warranted.

Download Full-text

Performance of Multifiber Beam Element for Seismic Analysis of Reinforced Concrete Structures

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455414500138 ◽

2014 ◽

Vol 14 (06) ◽

pp. 1450013 ◽

Cited By ~ 4

Author(s):

Xuan Huy Nguyen

Keyword(s):

Reinforced Concrete ◽

Damage Mechanics ◽

Seismic Analysis ◽

Axial Strain ◽

Nonlinear Behavior ◽

Bending Moment ◽

Axial Direction ◽

Beam Element ◽

Shaking Table ◽

Rc Structures

This paper presents a simplified modeling strategy for simulating the nonlinear behavior of reinforced concrete (RC) structures under seismic loadings. A new type of Euler–Bernoulli multifiber beam element with axial force and bending moment interaction is introduced. To analyze the behavior of RC structures in the axial direction, the interpolation of the axial strain is enriched using the incompatible modes method. The model uses the constitutive laws based on plasticity for steel and damage mechanics for concrete. The proposed multifiber element is implemented in the finite element Code_Aster to simulate the nonlinear behavior of two different RC structures. One structure is a building tested on a shaking table; the other is a column subjected to cyclic loadings. The comparison between the simulation and experimental results shows that the performance of this approach is quite good. The proposed model can be used to investigate the behavior of a wider variety of configurations which are impossible to study experimentally.

Download Full-text

Numerical Modeling of Time-Dependent Deformations of Concrete at 3D Analysis of Structures

10.31534/doct.049.dzola ◽

2020 ◽

Author(s):

◽

Ante Džolan

Keyword(s):

Reinforced Concrete ◽

Prestressed Concrete ◽

Concrete Structures ◽

Real Life ◽

Nonlinear Behavior ◽

3D Analysis ◽

Actual Behavior ◽

Realistic Simulation ◽

Highly Nonlinear ◽

Prestressed Structures

Concrete is a material with highly nonlinear behavior. In parallel, there are numerous secondary effects in concrete, such as aging, shrinkage, and creep, which further complicate the realistic simulation of reinforced concrete and prestressed concrete structures. In modern times, due to bolder construction, increasing spans and high rising construction, the need for realistic simulation of the behavior of concrete structures under conditions of various types of loads is becoming more pronounced. On the other hand, models with a small number of real-life parameters that can describe the actual behavior of concrete as accurately as possible are necessary. One such model, the previously developed model Precon 3D, which is based on a small number of parameters and can very well describe the behavior of concrete, reinforced concrete and prestressed structures for short-term static loads was taken as the basis for this work. Through this work, the numerical model Precon 3D has been upgraded with a model for following the behavior of concrete during time, i.e. the model has been upgraded with a model of creep and shrinkage of concrete, which is necessary for following the behavior of prestressed structures. The developed software has been tested against several experimental examples from the literature, with a very good match between numerical and experimental results.

Download Full-text

A New Method to Evaluate the Post-Earthquake Performance and Safety of Reinforced Concrete Structural Frame Systems

Infrastructures ◽

10.3390/infrastructures5020016 ◽

2020 ◽

Vol 5 (2) ◽

pp. 16

Author(s):

Foteini Konstandakopoulou ◽

George Hatzigeorgiou ◽

Konstantinos Evangelinos ◽

Thomas Tsalis ◽

Ioannis Nikolaou

Keyword(s):

Reinforced Concrete ◽

Seismic Performance ◽

Structural Parameters ◽

Permanent Deformation ◽

Nonlinear Behavior ◽

Building Structures ◽

Reinforced Concrete Buildings ◽

Concrete Buildings ◽

Residual Displacements ◽

Seismic Displacements

This study examines the relation between maximum seismic displacements and residual displacements for reinforced concrete building structures. In order to achieve a reliable relationship between these critical structural parameters for the seismic performance of concrete buildings, an extensive parametric study is conducted by examining the nonlinear behavior of numerous planar framed structures. In this work, dynamic inelastic analyses are executed to investigate the seismic behavior of two sets of frames. The first group consists of four planar frames which have been designed for seismic and vertical loads according to modern structural codes while the second group also consists of four frames, which have been designed for vertical loads only, in order to examine older structures that have been designed using codes with inadequate seismic provisions. These two sets of buildings are subjected to various earthquakes with different amplitudes in order to develop a large structural response databank. On the basis of this wide-ranging parametric investigation, after an appropriate statistical analysis, simple empirical expressions are proposed for a straightforward and efficient evaluation of maximum seismic displacements of reinforced concrete buildings structures from their permanent deformation. Permanent displacements can be measured in-situ after strong ground motions as a post-earthquake assessment. It can be concluded that the measure of permanent deformation can be efficiently used to estimate the post-seismic performance level of reinforced concrete buildings.

Download Full-text

Analytical modeling of textile reinforced concrete (TRC) sandwich panels: Consideration of nonlinear behavior and failure modes

Mechanics of Advanced Materials and Structures ◽

10.1080/15376494.2020.1750077 ◽

2020 ◽

pp. 1-20 ◽

Cited By ~ 1

Author(s):

Zakaria Ilyes Djamai ◽

Kamal Erroussafi ◽

Amir Si Larbi ◽

Ferdinando Salvatore ◽

Gaochuang Cai

Keyword(s):

Reinforced Concrete ◽

Analytical Modeling ◽

Failure Modes ◽

Sandwich Panels ◽

Nonlinear Behavior ◽

Textile Reinforced Concrete

Download Full-text

Theoretical Study on Steel Reinforced Concrete Hybrid Walls with Centered and Staggered Openings

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.812 ◽

2018 ◽

Vol 763 ◽

pp. 812-817

Author(s):

Daniel Dan ◽

Sorin Codrut Florut ◽

Viorel Todea ◽

Valeriu Stoian

Keyword(s):

Reinforced Concrete ◽

Lateral Displacement ◽

Experimental Studies ◽

Nonlinear Behavior ◽

Shear Walls ◽

Maximum Load ◽

Experimental Program ◽

Steel Reinforced Concrete ◽

Lack Of Information ◽

Hybrid Walls

Buildings placed in seismic areas are designed to simultaneously ensure strength, ductility and stiffness during earthquakes. In most cases the lateral resisting system is composed by shear walls. Lately for mid and high rise buildings the solution to use steel reinforced concrete shear walls, called hybrid walls, has been used. In most cases, the shear walls provided to limit the lateral displacement of the buildings, need to have openings due to architectural requirements. The existing theoretical and experimental studies presented in the literature refer to the behavior of solid/plain walls and a lack of information was identified for hybrid walls with openings. A theoretical and experimental program was developed at Politehnica University Timisoara, Romania with the aim to study the behavior of hybrid walls with centered and staggered openings. The current paper presents the results of nonlinear finite element analyses using ATENA package performed in order to assess the structural capabilities of the proposed experimental specimens with openings. Using the results obtained in one previous experimental program, consisting in tests on 1:3 scale steel-concrete composite elements, the paper presents a comparative study regarding the behavior of hybrid walls with openings versus solid walls. The study is focused on nonlinear behavior of elements with key parameters being evaluated, i.e. maximum load, deformation capacity and stiffens degradation.

Download Full-text

Behavior of Low, Medium and High Rise Reinforced Concrete Frame with Infill Using ATENA 2D

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2020.9063 ◽

2020 ◽

Vol 17 (9) ◽

pp. 4287-4293

Author(s):

D. Santhosh ◽

R. Prabhakara ◽

M. D. Ragavendra Prasad

Keyword(s):

Finite Element ◽

Reinforced Concrete ◽

Nonlinear Behavior ◽

Masonry Wall ◽

Nonlinear Behaviour ◽

Rc Frame ◽

Reinforced Concrete Frame ◽

Analysis And Design ◽

High Rise ◽

Finite Element Software

The Low, Medium and High rise reinforced concrete (RC) buildings are common in all cities in all countries. Unreinforced masonry wall (URW) is commonly used in low, medium and high rise building as a partition wall both in interior and exterior of building. But structural designers are not considered URW in analysis and design of buildings. This URM wall as an infill plays a very important role in structure subjected to lateral load. So it is very essential to know the nonlinear behavior of low, medium and high rise frame with and without infill. To conduct experiment for understanding the nonlinear behaviour of low, medium and high rise RC frame is very expensive and need good sophisticated testing facilities. With the available many finite element softwares, it is easy to create model and to know the performance of structure. So in this study, a finite element software ATENA 2D (2003) were used to conduct nonlinear analysis for capture nonlinear behaviour of low, medium and high rise RC frame with infill and without infill. Load versus displacement graphs, magnitude of principal compressive stresses, magnitude principal tensile stresses, stress contours, and cracks pattern are used to know the performance of low, medium and high rise RC frame with infill.

Download Full-text