scholarly journals Structural Optimization of Network Arch Bridges with Hollow Tubular Arches and Chords

2018 ◽  
Vol 12 (2) ◽  
pp. 36
Author(s):  
Alessio Pipinato
Keyword(s):  
Structural Analysis ◽  
Structural Optimization ◽  
Bridge Engineering ◽  
Structural Safety ◽  
Arch Bridge ◽  
Railway Bridges ◽  
Cable Structure ◽  
Arch Bridges ◽  
High Level

In the framework of bridge engineering, cable structure represent a key argument. The development of innovative bridge solutions are needed in order to keep time and costs at a reasonable level, maintaining at the same time an high level of structural safety and functionality. The network arch bridge solution completely respond to these requirements, and in addition could be designed as a very pleasant and formally elegant structure, because of its slenderness and lightness. In this paper, an introduction on the network arch solution is presented, together with structural analysis and data of relevant structures realized. Furthermore, an optimization of specific types of road and railway bridges is presented in the particular case of hollow sections, considering three alternative of cable disposition.

Bi-Directional Evolutionary Structural Optimization in Conceptual Bridge Design

2012 ◽  
Vol 256-259 ◽  
pp. 1658-1664
Author(s):  
Jian Xu ◽  
Jian Yuan Sun ◽  
Yu Long Shui
Keyword(s):  
Structural Optimization ◽  
Bridge Pier ◽  
Main Beam ◽  
Force Transmission ◽  
Bridge Design ◽  
Arch Bridge ◽  
Evolutionary Structural Optimization ◽  
Arch Bridges ◽  
Tied Arch Bridge

The principle and procedure of bi-directional evolutionary structural optimization (BESO) are stated in detail. A program based on BESO is introduced in conceptual bridge design. Topology optimizations are achieved for deck arch bridges with different rise-to-span ratios, half-through arch bridge, through tied arch bridge, bridge pier and bridge main beam. The results demonstrate rational structures with well-distributed stress and smooth force transmission, which indicates the efficient of the method.

scholarly journals Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Bin Chen ◽  
Xiaozhang Li ◽  
Xu Xie ◽  
Zheng Zhong ◽  
Pengzhen Lu
Keyword(s):  
Amplitude Spectrum ◽  
Element Model ◽  
Bridge Engineering ◽  
Fatigue Performance ◽  
Stress Process ◽  
Arch Bridge ◽  
Vehicle Data ◽  
Gross Vehicle Weight ◽  
Cable Force ◽  
Arch Bridges

In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

scholarly journals The Performance Assessment of a Precast, Panel-Segmented Arch Bridge with Outriggers

2019 ◽  
Vol 9 (21) ◽  
pp. 4646 ◽  
Author(s):  
Seok Hyeon Jeon ◽  
Kwang-Il Cho ◽  
Jungwon Huh ◽  
Jin-Hee Ahn
Keyword(s):  
Structural Analysis ◽  
Tensile Force ◽  
Three Dimensional ◽  
Compressive Force ◽  
Relative Difference ◽  
Environmental Damage ◽  
Material Strength ◽  
Arch Bridge ◽  
Construction Step ◽  
Arch Bridges

Stone arch bridges, which are globally implemented, are advantageous with respect to material strength and durability. To minimize environmental damage from arch bridges, a structurally stable scheme that can resist variable external loads is required. This paper proposes a segmented precast arch bridge with outriggers to resist both the tensile force applied on the precast panels and the compressive force during construction and use. To assess the structural behavior and safety of the proposed arch bridge, a three-dimensional (3D) nonlinear structural analysis was conducted, considering the construction step and rise ratio of the arch bridge. The structural analysis of the proposed arch bridge revealed that its maximum horizontal and vertical displacements occurred at the support of the precast panel and the arch crown in a self-weight state. However, because of the compressive resistance characteristics of the outriggers connected to the precast panels, the structure demonstrated an effective performance in the self-weight state. With an increase in the construction steps, and the final completion of proposed arch bridge via installation of the precast arch segments and earthwork for the precast arch bridge with outriggers, the deformation of the arch members was mitigated, and the relative difference between the stress distributions of the members reduced. Hence, the arch bridge achieved structural stability. Based on the thrust line analysis results of the arch bridge with respect to the construction step using 3D structural analysis results, the thrust line was formed outside the precast panel at the arch crown and support, so was attributed to the behavior of the arch bridge in a self-weight state. The thrust line was found to act within the precast panel depending on the construction step. Analysis results confirmed that the behavior of the precast panel arch bridge with the proposed outrigger was stable and structurally effective.

Stiffened CFRP-Panels Under Buckling Loads: Modeling, Analysis, Optimization

1995 ◽  
Author(s):  
Hans A. Eschenauer ◽  
Christof M. Weber
Keyword(s):  
Structural Analysis ◽  
Structural Optimization ◽  
Fiber Composite ◽  
Composite Plates ◽  
Optimization Process ◽  
Optimal Layout ◽  
Buckling Loads ◽  
Whole Process ◽  
Modeling Analysis ◽  
Complete Optimization

Abstract The present paper addresses the optimal layout of stiffened fiber composite plates (Fig. 1) considering buckling constraints; these plates are increasingly applied in many fields of engineering (air- and spacecraft technology, automotive industries, boatbuilding etc.). This particular area of structural optimization still requires substantial investigations into its fundamentals. The structural analysis alone for the treatment of this type of problems may increase to such a degree that the complete optimization process requires extremely long computation times due to the processing of a high amount of data, a fact that calls for the development of “intelligent” procedures in order to reduce the computation effort to a tolerable measure and to maintain reduplicability of the whole process. For this purpose, a so-called “constructive design model” is introduced.

scholarly journals Refined Finite Element Analysis of Crack Causes in SRC Arch Rib Bridges considering Multiple Factors

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Mengsheng Yu ◽  
Nianchun Deng ◽  
Qifeng Chen ◽  
Tianzhi Hao
Keyword(s):  
Steel Frame ◽  
Element Analysis ◽  
Shrinkage Temperature ◽  
Arch Bridge ◽  
Temperature Changes ◽  
Concrete Shrinkage ◽  
Shrinkage Process ◽  
Crack Problems ◽  
Arch Bridges ◽  
Bearing Structure

The SRC (steel-frame reinforced concrete) arch bridge is an important part of the development of arch bridges. Scholars worldwide have studied it from various aspects because of its stronger stiffness and stability than other types of bridges especially when crossing the canyon. The steel frame is a stress bracket during construction. Concrete becomes the main axial-pressure bearing structure when it fills the inner pipe and the encased frame. This article mainly focuses on the crack problems of SRC arch bridging during the postconstruction operation, local model of the midspan arch rib, and the equivalent relationship between the coefficient of expansion and the temperature of concrete. This study uses a cooling method to simulate the shrinkage process with detailed analysis of three properties including concrete shrinkage, temperature gradients, and concentrated hanger rod force. It is concluded that the SRC arch bridge will have large tensile stress on both inner and outer surfaces of slab and web when the temperature changes, and it is the main cause of cracks. The results agree well with measured data. At last, we come up with some reference suggestions in the design and construction of similar bridges in the future.

A Study on the Characteristics of Bogie Frame Materials

2013 ◽  
Vol 420 ◽  
pp. 144-148 ◽  
Author(s):  
Sung Cheol Yoon ◽  
Yeon Su Kim ◽  
Joon Hyung Ryu ◽  
Sung Hyuk Park ◽  
Geun Soo Park
Keyword(s):  
Structural Analysis ◽  
Performance Test ◽  
Structural Safety ◽  
Combined Stress ◽  
Bogie Frame ◽  
Test Standards ◽  
Rail Vehicles ◽  
Urban Rail ◽  
Load Tests ◽  
And Performance

This paper describes the structural analysis, load tests and combined stress of the bogie frame. It seeks to identify the structural safety of the bogie frame when the bogie is assembled on the train and a train service is implemented. The bogie consists of the bogie frame, suspension, wheels, brakes and transmission, etc. The bogie frame can be considered as the most important part of the bogie. The analysis and tests were evaluated using JIS E 4207 standards and performance test standards for urban rail vehicles.

Novel Hanger Design to Improve the Robustness of Through Arch Bridges

2011 ◽  
Vol 90-93 ◽  
pp. 862-868
Author(s):  
Qi Ming Wu ◽  
Dang Qi Yang ◽  
Fei Cui ◽  
Xiao Wei Yi ◽  
Rui Juan Jiang
Keyword(s):  
Progressive Collapse ◽  
Time History ◽  
Structural Members ◽  
New Approach ◽  
Arch Bridge ◽  
Structural Robustness ◽  
Arch Bridges ◽  
Dynamic Time ◽  
The Impact ◽  
Emergency Measures

Hangers in through arch bridges are important components since they suspend the bridge deck from the arch ribs. Local damage at a hanger may lead to progressive damage of various components in the arch bridge or even progressive collapse of the bridge. In this paper, the conventional design of double-hangers in through arch bridges is reviewed. Then a new approach to design the double-hangers is put forward. The suitability and robustness of this approach is then verified by a numerical simulation of a real through arch bridge. The impact effects induced by local hanger fracture on other structural members are simulated by dynamic time-history analyses. The new approach to design the hangers for through arch bridges is shown to improve the structural robustness. With the application of the new way put forward here, when one or more hangers are damaged to fail, the through arch bridge will not be endangered and will still maintain the overall load-bearing capacity during an appropriate length of time to allow necessary emergency measures to be taken, which illustrates the leading principle of structural robustness well.

Study on Reliability Evaluation Method of Existing CFST Arch Bridge

2012 ◽  
Vol 226-228 ◽  
pp. 1679-1682
Author(s):  
Yi Song Zou ◽  
Hai Tao Hou ◽  
Wei Peng
Keyword(s):  
System Reliability ◽  
Reliability Index ◽  
Evaluation Method ◽  
Reliability Assessment ◽  
Steel Tube ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Arch Bridges ◽  
Grading Standards ◽  
Bridge System

Based on reliability theory, the application calculation method of Concrete Filled Steel Tube (CFST) arch bridge system reliability index is studied. Select the most unfavorable load distribution in working condition of maximum moment and deflection at the mid-span, from the angle of strain energy, calculated the weights of CFST arch ribs component. On the basis of the grading standards of reliability assessment of the existing bridge components and the critical structures, CFST arch bridge system reliability assessment grading standards are constructed. CFST arch bridges reliability index are evaluated from two aspects (the arch ribs and segment) in this article. As the CFST arch bridge locates in the marine environment, corrosion environment is the serious level of C5-M, steel pipe corrosion is the major diseases of CFST, arch rib which on the corrosion conditions were assessed. The results show that the method can effectively assess the situation of CFST arch bridge.

STRUCTURAL ANALYSIS OF CARBON COMPOSITE FRAME FOR FOLDABLE ELECTRIC WHEELCHAIR DEVELOPMENT

2019 ◽  
Vol 19 (07) ◽  
pp. 1940045
Author(s):  
WOO SUK CHONG ◽  
MI YEON SHIN ◽  
CHANG HO YU
Keyword(s):  
Structural Analysis ◽  
Compressive Stress ◽  
Safety Factor ◽  
Carbon Composite ◽  
The Body ◽  
Frame Structure ◽  
Structural Safety ◽  
Maximum Displacement ◽  
Electric Wheelchair ◽  
Maximum Variation

Electric wheelchairs developed so far have difficulties for elderly people to use, because of their bulkiness and heavy weight. To address this problem, this study presents a design for the construction of an electric wheelchair with an application of light duty materials at frame and a foldable structure that can be easily loaded in a narrow space. A structural analysis was performed to evaluate the structural safety of the foldable wheelchair. For the purpose of analysis, a carbon composite was used as the material for the frame; Structure Mechanics Module of COMSOL Multiphysics was used as the analysis software; and for the boundary condition, the lower part of the body frame was fixed, and a load of 150[Formula: see text]kg was applied to the upper part of the wheelchair. According to the results of the structural analysis, a maximum displacement of 2.869[Formula: see text]mm occurred at the handle where the carbon composite was applied, and tensile and compressive stress of 103[Formula: see text]MPa and 107.3[Formula: see text]MPa, respectively, were measured at the seat part of the wheelchair where the load was applied. The safety factors were 7.5 and 5.5 for tensile stress and compressive stress, respectively. A maximum variation of 0.0872[Formula: see text]mm occurred at the aluminum wheel shaft, and a maximum variation of 0.2046[Formula: see text]mm occurred at the joint. The maximum stress was 116.3[Formula: see text]MPa that corresponded to a safety factor of 2.66; this indicates that the wheelchair can be considered to be structurally safe as the safety factor exceeds the initial target of 2.

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