Torsional behavior of a hybrid FRP-aluminum space truss bridge: Experimental and numerical study

2018 ◽  
Vol 157 ◽  
pp. 132-143 ◽  
Author(s):  
Dongdong Zhang ◽  
Qilin Zhao ◽  
Feng Li ◽  
Jie Tao ◽  
Yifeng Gao
Keyword(s):  
Numerical Study ◽  
Space Truss ◽  
Torsional Behavior ◽  
Truss Bridge

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

scholarly journals Experimental and Numerical Study for the Shaping Formation of SCST Structures by Cable-tensioning

2013 ◽  
Vol 7 (1) ◽  
pp. 77-83
Author(s):  
J.W. Kim ◽  
J. H. Doh ◽  
S. Fragomeni
Keyword(s):  
Numerical Study ◽  
Geometric Model ◽  
Small Scale ◽  
Element Analysis ◽  
Construction Technique ◽  
Construction Methods ◽  
Space Truss ◽  
Test Models ◽  
Scale Test ◽  
Joint Behaviour

This paper discusses the behaviour characteristics of the shaping formation of Single-Chorded Space Truss (SCST) structures by means of cable-tensioning of bottom chords. The innovative technique is fast and economical and issued in many types of space structures. The small-scale test models presented herein consist of uniform pyramids with multi-directional ball type joints which are erected into their final shape by cable-tensioning. Since the joint behaviour is very significant in studying the shaping of SCST structures, basic tests for beam and pyramidal units were performed. The feasibility of the proposed cable-tensioning technique and the reliability of the established geometric model were confirmed by finite element analysis. The proposed cable-tensioning technique indicates that the behaviour characteristic of joints is very important in the shaping formation of SCST structures. More specifically in situations where heavy cranes are inaccessible, the cable-tensioning construction technique has proven to be an easy and reasonable method compared to conventional construction methods that typically include heavy cranes and scaffolding.

Flexural properties of a lightweight hybrid FRP-aluminum modular space truss bridge system

2014 ◽  
Vol 108 ◽  
pp. 600-615 ◽  
Author(s):  
Dongdong Zhang ◽  
Qilin Zhao ◽  
Yaxin Huang ◽  
Fei Li ◽  
Haosen Chen ◽  
...  
Keyword(s):  
Modular Space ◽  
Flexural Properties ◽  
Space Truss ◽  
Truss Bridge ◽  
Bridge System

Analytical solutions of the torsional mechanism for a new hybrid fiber-reinforced polymer–aluminum twin-trackway space truss bridge

2016 ◽  
Vol 19 (12) ◽  
pp. 1832-1840 ◽  
Author(s):  
Dongdong Zhang ◽  
Feng Li ◽  
Qilin Zhao ◽  
Yingchang Duan
Keyword(s):  
Analytical Solutions ◽  
Fiber Reinforced Polymer ◽  
Torsional Stiffness ◽  
Torsional Angle ◽  
Fiber Reinforced ◽  
Pure Torsion ◽  
Space Truss ◽  
Reinforced Polymer ◽  
Torsional Mechanism ◽  
Truss Bridge

For emergency purposes, a lightweight space truss bridge was designed. The bridge is composed of twin triangular deck-truss beams incorporating new structural forms and advanced fiber-reinforced polymer profiles. As a new structure, the structural properties of its triangular deck-truss beam have been studied in detail; however, a design-oriented study facilitating the application of the entire twin-trackway bridge under pure torsion remains to be undertaken. The objective of this article is to analytically explore the torsional mechanism of the twin-trackway bridge, which is characterized by torsional angle and torsional stiffness. To verify the derivation procedures and formulae, the pure torsion test and numerical analysis are conducted on a full-scale specimen. The results indicate that the analytical solutions compare well with the experimental and numerical results. The torsional moment is primarily resisted by the vertical bending of twin triangular deck-truss beams. The simplified analytical model can be used with sufficient accuracy for the design of the bridge.

scholarly journals Damage Identification in Warren Truss Bridges by Two Different Time–Frequency Algorithms

2021 ◽  
Vol 11 (22) ◽  
pp. 10605
Author(s):  
Lorenzo Bernardini ◽  
Marco Carnevale ◽  
Andrea Collina
Keyword(s):  
3D Model ◽  
Damage Identification ◽  
Numerical Study ◽  
Continuous Wavelet ◽  
Monitoring Methods ◽  
Hilbert Transforms ◽  
Damage Level ◽  
Time Frequency ◽  
Truss Bridges ◽  
Truss Bridge

Recently, a number of authors have been focusing on drive-by monitoring methods, exploiting sensors mounted on the vehicle rather than on the bridge to be monitored, with clear advantages in terms of cost and flexibility. This work aims at further exploring the feasibility and effectiveness of novel tools for indirect health monitoring of railway structures, by introducing a higher level of accuracy in damage modelling, achieve more close-to-reality results. A numerical study is carried out by means of a FE 3D model of a short span Warren truss bridge, simulating the dynamic interaction of the bridge/track/train structure. Two kinds of defects are simulated, the first one affecting the connection between the lower chord and the side diagonal member, the second one involving the joint between the cross-girder and the lower chord. Accelerations gathered from the train bogie in different working conditions and for different intensities of the damage level are analyzed through two time-frequency algorithms, namely Continuous Wavelet and Huang-Hilbert transforms, to evaluate their robustness to disturbing factors. Compared to previous studies, a complete 3D model of the rail vehicle, together with a 3D structural scheme of the bridge in place of the 2D equivalent scheme widely adopted in the literature, allow a more detailed and realistic representation of the effects of the bridge damage on the vehicle dynamics. Good numerical results are obtained from both the two algorithms in the case of the time-invariant track profile, whereas the Continuous Wavelet Transform is found to be more robust when a deterioration of track irregularity is simulated.

Sensitivity of Space Trusses to Sudden Member Loss

1997 ◽  
Vol 12 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Ahmed El-Sheikh
Keyword(s):  
Aspect Ratio ◽  
Numerical Study ◽  
Concrete Slab ◽  
Severe Damage ◽  
Composite Action ◽  
Space Truss ◽  
Supporting Condition ◽  
High Degree ◽  
Space Trusses

Space trusses typically contain a large number of members, and possess a high degree of statical indeterminacy. However, a number of members have been identified as critical to truss integrity, with the loss of any of them likely to produce serious strength reductions. Furthermore, when these members are lost suddenly, e.g. due to the failure of a faulty connection or the buckling of a slender member, their forces are shed into the structure in a dynamic manner, leading to yet more severe damage. This paper presents a numerical study on the sensitivity of space trusses to both gradual and sudden member losses. The effect of composite action between a top concrete slab and a space truss in reducing this sensitivity is assessed. Other factors that are also considered in this work include the truss aspect ratio and supporting condition.

Experimental and Numerical Study on Torsional Behavior of Precast Concrete Screw Pile Body

2012 ◽  
Vol 188 ◽  
pp. 137-143
Author(s):  
Xin Li ◽  
Li Liang
Keyword(s):  
Numerical Study ◽  
Precast Concrete ◽  
Unit Length ◽  
Numerical Test ◽  
Element Model ◽  
Concrete Cover ◽  
Design Parameters ◽  
Screw Pile ◽  
Concrete Pile ◽  
Torsional Behavior

Precast concrete screw pile is a new kind of pile foundation. Because the pile bears very large torsion in construction, the torsional properties of pile body including cracking torsion, ultimate torsion and torsional deformation were studied in this paper in order to improve the anti-torsional ability of precast concrete screw pile. Experimental method and numerical method are used to research the torsional behavior of precast concrete pile body. Experimental and numerical results of cracking torsion, ultimate torsion and relationship between torsion and angle of twist per unit length of different specimens are obtained. In addition, five factors of strength level of concrete, degree of prestress, distance of spiral hoop, concrete cover and diameter of spiral hoop influencing on torsional behavior of precast concrete pile body are researched by orthogonal numerical test. The rational finite element model and solution method are concluded for calculating the torsional behavior of concrete pile. Moreover, the rational pile type and design parameters of precast concrete screw pile are obtained.

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