scholarly journals Fatigue strength of steel plate girder railway bridges with butt joints reinforced with one-sided rhomb-shaped cover plates

2021 ◽  
Vol 93 (3) ◽  
pp. 31-40
Author(s):  
Krzysztof Konecki ◽  
Bernard Wichtowski
Keyword(s):  
Computational Analysis ◽  
Load Capacity ◽  
Steel Structures ◽  
European Convention ◽  
Butt Joints ◽  
Railway Bridges ◽  
Fem Method ◽  
Bridge Structures ◽  
Service Degradation ◽  
Cover Plates

Abstract: Due to the long period of service degradation, bridge structures require periodic technical inspections and assessment of the current load capacity. Since the 1970s, this assessment has been carried out according to the Fitness for Purpose criterion. From 2008, the PUK criterion has been replaced with the recommendations of the European Convention on Steel Structures (ECCS). As part of these recommendations, the authors decided to explain the previously obtained unrealistic values of the fatigue class Dsc of the bridge butt joints, covered with one-sided rhomb-shaped cover plates. The computational analysis performed with the FEM method gave excellent results which are briefly presented in the article.

scholarly journals Analysis of the technical condition of a railway bridge at risk of failure

2019 ◽  
Vol 284 ◽  
pp. 01005
Author(s):  
Mieczysław Piechota ◽  
Grzegorz Rogojsz
Keyword(s):  
Load Capacity ◽  
Degradation Process ◽  
Technical Condition ◽  
Steel Bridge ◽  
Bridge Structure ◽  
Railway Bridge ◽  
Railway Bridges ◽  
Actual Load ◽  
Bridge Structures

The paper presents an analysis of the technical condition of a railway bridge structure with a span structure in the form of welded girders. Static diagram of the structure consists of two simply supported beams. The theoretical span of the spans is 2 x 14.50 m, their overall length is 14.90 m, and the total length of the crossing is 30.6 m. The reasons for the formation and development of bridge degradation were analysed. In addition, the actual load capacity of the structure was determined and the possibility of its further operation was evaluated. Particular attention was given to the quality of workmanship and the degradation progress of welded joints, which led to the exclusion of the object from use. The main purpose of the presented analyses is to formulate general recommendations, whose implementation in a direct or indirect form may contribute to reducing the degradation process of railway steel bridge structures. When inspecting welded railway bridges, particular attention should be paid to the condition of welds and to control and prevent the structure from cracking.

scholarly journals Biaxial Shear Load Capacity of Anchor System for Quick-Hardening Track on Railway Bridges

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Kyoung Chan Lee ◽  
Il-Wha Lee ◽  
Seong-Cheol Lee
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Load Capacity ◽  
Frictional Resistance ◽  
Shear Capacity ◽  
Railway Track ◽  
Railway Bridges ◽  
Anchor System ◽  
Ballast Track ◽  
Anchor Systems

Quick-hardening railway track was developed to rapidly convert old-style ballast track to slab track in order to improve its maintainability and ride comfort. On bridges, quick-hardening track is applied in a segmented structure to reduce the temperature constraint, and anchors at the centers of the segments securely couple the track to the bridge. In this study, an anchor system is proposed that facilitates fast construction, and two designs for the proposed anchor systems are provided along with experimental test results of the same. Two anchor system designs were developed to allow for the maximum possible longitudinal and transverse loads in high-speed railways while considering the frictional resistance between the track slab and bridge deck. The biaxial shear capacity of each design was investigated experimentally, and the structural capacity for biaxial shear loads was evaluated using an elliptical curve to represent the longitudinal and transverse shear capacities. The minimum friction coefficient was determined based on the results of the evaluation to minimize damage to the anchor. The results obtained from the experiments confirmed that the proposed anchor systems possess sufficient shear capacity for application on high-speed railway bridges.

scholarly journals Effects of Surrounding Earth on Shell During the Construction of Flexible Bridge Structures

2019 ◽  
Vol 41 (2) ◽  
pp. 67-73
Author(s):  
Czesław Machelski
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Static Condition ◽  
Steel Bridge ◽  
Interfacial Interactions ◽  
Soil Medium ◽  
Bridge Structures ◽  
Internal Forces ◽  
Bearing Loads ◽  
Corrugated Plates

AbstractA characteristic feature of soil-steel structures is that, unlike in typical bridges, the backfill and the carriageway pavement with its foundation play a major role in bearing loads. In the soil-steel structure model, one can distinguish two structural subsystems: the shell made of corrugated plates and the backfill with the pavement layers. The interactions between the subsystems are modelled as interfacial interactions, that is, forces normal and tangent to the surface of the shell. This is a static condition of the consistency of mutual interactions between the surrounding earth and the shell, considering that slip can arise at the interface between the subsystems. This paper presents an algorithm for determining the internal forces in the shell on the basis of the unit strains in the corrugated plates, and subsequently, the interfacial interactions. The effects of loads arising during the construction of a soil-steel bridge when, for example, construction machines drive over the structure, are taken into account in the analysis of the internal forces in the shell and in the surrounding earth. During construction, the forces in the shell are usually many times greater than the ones generated by service loads. Thus, the analytical results presented in this paper provide the basis for predicting the behaviour of the soil medium under operational loads.

scholarly journals Особенности деформаций главных балок железобетонных пролетных строений автодорожных мостов при их усилении внешней арматурой

2020 ◽  
Vol 44 (3) ◽  
pp. 151-158
Author(s):  
S. Tomilov
Keyword(s):  
Carrying Capacity ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Main Beam ◽  
Relative Deformation ◽  
Operational Parameters ◽  
The Road ◽  
External Reinforcement ◽  
Bridge Structures ◽  
High Degree

Так как в настоящее время в эксплуатации находится достаточно много автодорожных мостов, запроектированных и построенных в различные периоды, их, как и всю дорожную сеть, необходимо поддерживать в состоянии, соответствующем нормативам, а для этого проводить ремонт с использованием элементов усиления несущих конструкций. При качественном возведении и надлежащем уходе высокая степень сохранности мостов позволяет продлить срок их службы путем решения ряда конструктивных вопросов, наиболее актуальным из которых считают обеспечение нормативной грузоподъемности. Усиление с целью повышения грузоподъемности эксплуатируемых мостов достигается путем добавления элементов внешних или внедренных в состав существующего конструктива в зависимости от типа сооружения, его состояния и доступной технологии производства. Однако не только грузоподъемность, но и подверженность конструкций деформациям определяет транспортно-эксплуатационные параметры сооружения, характеризующие послеремонтное состояния моста. Цель настоящего исследования – анализ известного и широко востребованного способа усиления железобетонных балок внешним армированием как обеспечивающего минимальное вмешательство в существующие основные конструкции, технологичного и доступного в исполнении. Впервые дана оценка влияния стадийности включения в работу элементов усиления на общие деформации – прогибы главных балок. Ключевые слова: главная балка, грузоподъемность, усиление, внешняя арматура, свободная затяжка, стадийность работы, относительная деформация, прогиб. Currently, there are quite a lot of road bridges in operation, designed and built in different periods. It is necessary to maintain the road network including bridge structures in a condition that meets up-to-date standards, and for this repair should be carried out using reinforcing elements of the supporting structures. With high-quality construction and proper maintenance, a high degree of safety of bridges allows to extend their service life by solving a number of design issues, the most important of which is considered to be the provision of standard load capacity. Strengthening in order to increase the carrying capacity of operated bridges is achieved by adding elements external or incorporated into the existing structure, depending on the type of structure, its condition and available production technology. However, not only the carrying capacity, but also the susceptibility of structures to deformations determines the transport and operational parameters of the structure, which characterize the post-repair state of the bridge. The purpose of this study is to analyze the well-known and widely demanded method of reinforcing reinforced concrete beams with external reinforcement as providing minimal interference with the existing basic structures, technological and affordable in execution. For the first time, an assessment of the influence of the staging of the inclusion of reinforcement elements in the work on the general deformations – deflections of the main beams. Keywords: main beam, carrying capacity, reinforcement, external reinforcement, free rod, staging of work, relative deformation, deflection.

Assessment of Corrosion Effects on Railway Bridges in the Middle Area of Vietnam Using Multibody Dynamics Approach

2020 ◽  
Vol 897 ◽  
pp. 3-11
Author(s):  
My Pham ◽  
Cong Thuat Dang ◽  
Chinh Van Nguyen
Keyword(s):  
Numerical Model ◽  
Multibody Dynamics ◽  
Dynamic Testing ◽  
Load Capacity ◽  
Moving Load ◽  
Localized Corrosion ◽  
Steel Bridge ◽  
Actual Measurement ◽  
Railway Bridges ◽  
Bridge Model

A railway bridge over several decades will be degraded due to localized corrosion. As a result, the load capacity of the bridge decreases, especially under the live load caused by trains. This paper examines the residual load capacity of a bridge deteriorated by localized corrosion by using the multibody dynamics approach. This approach allows an accurate description of the interaction between trains and bridges. At the same time, it allows the formation of corrosion marks on each structural member of the bridge in a numerical model precisely based on actual measured data. In order to describe accurately the remaining load of the bridge under the moving load of the train, a dynamic testing and finite element modeling of a steel bridge are conducted and compared. At the same time, the results are also compared with the simulation results of the bridge model before being corroded. In addition, the paper also tests the reliability of the numerical model for assessments of similar bridges without actual measurement results that are costly and time-consuming.

scholarly journals Study on Calculation of Bearing Capacity of Axially Loaded CFRP-Strengthened Cold-Formed Thin-Walled Lipped Channel Steel Columns

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yanan Sun ◽  
Pengfei Li ◽  
Guojin Qin
Keyword(s):  
Carbon Fiber ◽  
Bearing Capacity ◽  
Load Capacity ◽  
Slenderness Ratio ◽  
Steel Structures ◽  
Fiber Reinforced ◽  
Bonding Agents ◽  
Steel Column ◽  
Thin Walled ◽  
Carbon Fiber Reinforced

With the development of carbon fiber reinforced composites and the continuous improvement of the properties of bonding agents, scholars recommended using carbon fiber reinforced plastics (CFRP) to enhance cold-formed thin-walled C-shaped steel structures. It can provide a fast and effective way to strengthen and repair damaged steel structures. However, discussion on the bearing capacity calculation of cold-formed thin-walled C-section steel column strengthened by CFRP was limited. Also, the relevant influencing factors (the number of CFRP reinforcement layers), the orientation of CFRP (horizontal, vertical), and the location of CFRP reinforcement (web + flanges + lips, web + flanges, web, and flanges) were overlooked in calculating the bearing capacity of cold-formed thin-walled C-section steel column strengthened by CFRP. Then, the calculation result of the load capacity will be inaccurate. This work, therefore, studied the effects of CFRP reinforcement layers, CFRP direction, and CFRP reinforcement position on the ultimate load of CFRP-strengthened cold-formed thin-walled C-section steel column. A three-dimensional (3D) finite element model of cold-formed thin-walled steel strengthened by CFRP was established to discuss the bearing capacity under axial compression. Furthermore, a method for calculating the bearing capacity of the CFRP-strengthened cold-formed thin-walled C-section steel column was proposed based on the direct strength methods (DSM). The results indicate that not only the slenderness ratio, section size, and length of members but also the number of CFRP reinforcement layers and orientation of CFRP have an impact on the calculation of bearing capacity. The equation modified in this work has excellent accuracy and adaptability. Predicting the bearing capacity of reinforced members is necessary to give full play to the performance of CFRP accurately. Thus, the methods proposed can provide a reference value for practical engineering.

scholarly journals A critical assessment of domestic and foreign temporary vertical regulatory loads on road bridge structures, a way to eliminate their identified shortcomings

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Pavel Salamahin ◽  
Ilya Reshetnikov
Keyword(s):  
Carrying Capacity ◽  
Road Traffic ◽  
Load Capacity ◽  
Regulatory Documents ◽  
Combined Loads ◽  
Bridge Structures ◽  
The Usa ◽  
The Russian Federation ◽  
Uniformly Distributed Loads ◽  
Economic Considerations

The article critically assessed temporary vertical standard combined loads on road bridges in Western European countries, the USA and Russia. They are set with constant values of the parameters of their uniformly distributed loads and loads on the axles of trucks without regard to the composition of road traffic and out of communication with the length and shape of the lines of influence of force and deformation factors in the elements of bridge structures and are used in these and in many other countries in road bridge structures engineering and design. It is shown that the bridges constructed with different spans on the same road are designed to have different and unknown for designers, engineers and facility managers load capacity, which decreases when the length of the spans increases more than twice, but that is unacceptable for operational and economic reasons. The author found that the use of regulatory documents of other countries as a model for the modernization of domestic standards is unacceptable due to economic considerations. The article assesses the carrying capacity of such bridges as: the Crimean bridge and the Bugrinsky bridge in Novosibirsk. It is shown that these structures, in case of compliance with the requirements of modern regulatory documents of the Russian Federation, do not allow for the passage of columns of vehicles weighing more than 25–27 tons in a state of congestion. The ways of eliminating the identified deficiencies of these combined regulatory loads are indicated. The results of calculations are presented, indicating that a further increase in the parameter K of the AK load to large values is not an effective way of ensuring the required carrying capacity of bridge structures.

scholarly journals CALCULATION OF RELIABILITY OF REINFORCED CONCRETE FLIGHT STRUCTURES

2021 ◽  
pp. 18-25
Author(s):  
Roman Kaplin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Element Model ◽  
Operating Conditions ◽  
Structural Element ◽  
Reinforced Concrete Slab ◽  
Bridge Structures ◽  
Number Of Cycles ◽  
Office Software

A large number of bridges are operated on the roads of Ukraine. The increase in the intensity and speed of traffic leads to qualitative changes in the operating conditions of bridge structures, which is characterized by a sharp increase in the number of cycles under load of bridge elements, and to the development of damage in them. For trouble-free operation and efficient use of bridge structures it is very important to have reliable estimates of the actual load capacity and resource, taking into account the loads, material quality, nature of the structure. The solution of the problem in this statement is possible only on the basis of the theory of reliability. However, its application to specific assessments of durability and reliability of structures is associated with the solution of a set of issues: the identification of patterns of change of various parameters, the accumulation of reliable and easy to calculate statistics on loads and mechanical characteristics of materials, etc. It is necessary to know that the strength of the material (sample) of the structural element and the structure as a whole are completely different things. The article considers a new design of reinforced concrete girder structure, using perforated metal elements and an effective reinforced concrete slab of the carriageway. On its basis, a computational model in the form of a finite-element model built in the SCAD-Office software package is formed. As a result of calculations, the components of the stress-strain state of the structure are obtained. Based on the obtained results, the reliability of the structure was calculatedunder the influence of modern regulatory loads. 

A new deck arch bridge and a study on its mechanical properties by FE and experiment methods

2021 ◽  
pp. 136943322110427
Author(s):  
Xia Qin ◽  
Mulin Pang ◽  
Xiaoli Xie ◽  
Chenyu Yan ◽  
Mingzhe Liang
Keyword(s):  
Mechanical Properties ◽  
System Design ◽  
High Speed ◽  
Dynamic Properties ◽  
Steel Structures ◽  
Arch Bridge ◽  
Railway Bridges ◽  
New Type ◽  
Stability Principle ◽  
Rise Height

In this study, a new type of deck arch bridge was proposed based on the triangle stability principle, and its mechanical properties were tested. The new deck arch bridge—named the superposed truss arch bridge—consists of main arches, auxiliary arches, a girder, and web members. These components adopt steel structures and are connected into a series of triangles to form a superposed truss structure. The new structural system design retains the advantages of the truss and arch structure. Additionally, the rise-span ratio of the main arch can be smaller in the new system design, so the rise height is smaller, which can decrease construction difficulty. The underlying mechanical principles of the new bridge were explained. A new type of railway deck arch bridge with a 650 m span was designed, and the finite element method was used to analyze its stiffness, strength, stability, and dynamic properties and the corresponding effects of the arch-axis coefficient, rise-span ratio, and span length on the mechanical properties. An experiment was carried out on a new deck arch bridge and a conventional deck arch bridge with the same span (10 m) to compare their performance. The results showed that the new deck arch bridge exhibited good mechanical properties while being inexpensive and easy to construct, which makes it suitable for high-speed railway bridges.

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