Soil-steel Bridge Research Articles

Displacements of shell in soil-steel bridge subjected to moving load: determination using strain gauge measurements and numerical simulation

Abstract This paper analyses displacements of a shell in a soil-steel bridge subjected to quasi-static moving loads. The considerations relate to a large span structure located in Ostróda, Poland. In particular, shell displacements during a loading cycle consisting of consecutive passages of a pair of trucks over the bridge are investigated. The results of a full-scale test, that is, the readings from a system of strain gauges arranged along the shell circumferential section, are the basis for determination of shell displacements. The proposed algorithm makes it possible to calculate any component of the displacement using just a simple model of the shell in the form of a linear elastic curvilinear beam. The approach uses real measurements, and thus, it yields results of displacements reflecting the actual mechanical behaviour of the entire composite structure including not only the shell, but also the backfill, the pavement, etc. The calculated state of displacement sets the basis for calibration of the numerical model. Finite element (FE) analyses include staged construction, that is, backfilling the shell by placing successive soil layers, as well as the loading test with the vehicles moving over the bridge. It is demonstrated that the ballasting of the shell during backfilling contributes to the improvement of the simulated behaviour of the object at the stage of operation, that is, when subjected to moving truck load. Thus, the calibration of the FE model is successfully carried out using the results of strain gauge measurements.

Performance of large-span arched soil–steel structures under soil loading

This paper investigates the structural behavior and soil–structure interaction mechanism of very large-span arched soil–steel structures constructed using steel plates with deep corrugation profile, 500 mm X 237 mm, during and after construction. Field measurements were employed to validate three-dimensional (3D) finite element model (FEM), which was then employed to evaluate the performance characteristics of very large span soil–steel structures. In addition, the FEM was used to evaluate the effectiveness of various strengthening techniques employed for buried steel structures to withstand very large spans, including lateral reinforced steel mesh and circumferential steel stiffeners. The world’s largest-span arched soil–steel bridge constructed using 12 mm thick steel plates with the deepest corrugation profile, of 237 mm total depth and 500 mm pitch was instrumented extensively to monitor the displacements and straining actions of the steel structure. The steel structure has a span of 32.40 m and vertical height of 9.57 m. Lateral reinforced steel mesh was attached to the steel structure and cement-stabilized soil was added to a certain level to enhance the performance of the structure during and after construction. The calculated deformations and straining actions captured the same trend of the field measurements. The numerical results indicated that two main critical zones of the steel structure, the crown and at the change of arc radii (40 degrees from the top arc on each side), were observed to experience high axial stresses, which could cause buckling and should be considered carefully in the structural design. Finally, the numerical results revealed that the deployed steel mesh reinforcement in the current study reduced the induced straining actions in buried structures with up to 50%, while the investigated circumferential steel stiffeners could control the crown vertical deformations down to 0.5% of the structure rise during and after construction.

Scheme analysis of the structure founded on the piles in soil-steel bridge

Abstract: In soil-steel bridges usually the massive concrete foundation is being applied. When the structure is mounted in the gutter, the static models defined as non-sliding joint arch. In a few cases only, the corrugated steel structures are founded on a flexible foundation. The examples of such objects executed in Poland were described in this article. The flexible foundation of the steel structure helps to form a natural vault in the backfill. The shape of the structure, similar to parabolic arch, is relevant in this case. The essential case being analyzed here, is the structure founded on the piles made of steel pipes. It is characterized by variable static scheme resulting from the level of connection. The displacement scheme was established using the results of geodetic measurements performed on the constructed bridge. On this basis, the range of changes in the uplift of the structure during backfilling, was estimated in the structure model. Keywords: Soil-steel bridges; Flexible foundation; Static scheme; Investigation

Expanded range of testing of soil-steel bridge with use moving loads

n this paper the results of the live load tests of soil steel bridge are presented. The structure was designed with use of the largest possible corrugation type UltraCor. Parameters of analysed structure were referred to the current record structures in the term of span. Standard test procedure have been expended to check the efficiency of the position-changing loads i.e live loads but in a quasi-static approach. The measuring base was the upper part of the shell periphery equipped with inductive and dial gauges to determine deflections at regular layout. Paper presents another example of the formation of “hysteresis loop” where the live load is passing back and forth along the same path. In the case of a dense layout of measuring points it is possible to use a differential algorithm to estimate the bending moments in corrugated steel plates. Analysed case shows that the internal forces and displacements due to the live loads are much smaller than during construction. The purpose of the paper is to indicate the specific behaviour of soil-steel structures in relation to classical arch bridges.

Non-Destructive Testing of the Longest Span Soil-Steel Bridge in Europe-Field Measurements and FEM Calculations.

The article describes interdisciplinary and comprehensive non-destructive diagnostic tests of final bridge inspection and acceptance proposed for a soil-steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure short-term response was collected. Periodic diagnostics of bridge deformations was done one year after it was built. Load test design was based on numerical simulations performed by means of finite element method (FEM). In situ measurements were done with the aid of: inductive sensors, optical total station, and terrestrial laser scanner. The results produced by terrestrial laser scanning were used to build a precise image of structure deformation in 3D space during the tests. The accuracy of laser mapping was significantly increased using the information coming from total station and inductive sensors. These have higher accuracy and therefore can be used as reference. Thus, new quality in measurements is introduced. Good correspondence between in situ values and FEM estimations was achieved. Therefore, such a combination of testing methods can be used in non-destructive diagnostics of structures and is an interesting alternative for the standard approach, in which the measurements are done in limited number of points.

Application of EPS Geofoam to a Soil–Steel Bridge to Reduce Seismic Excitations

There have only been a limited number of analyses of soil–steel bridges under seismic and anthropogenic (rockburst) excitations. Rockbursts are phenomena similar to low-intensity natural earthquakes. They can be observed in Poland (Upper and Lower Silesia) as well as in many parts of the world where coal and gas are mined. The influence of rockbursts and natural earthquakes on soil–steel bridges should be investigated because the ground motions caused by these two kinds of excitations differ. In the present paper, a non-linear analysis of a soil–steel bridge was carried out. Expanded polystyrene (EPS) geofoam blocks were used in a numerical model of the soil–steel bridge to buffer the seismic wave induced by a rockburst (coming from a coal mine) as well as a natural earthquake (El Centro record). The analyzed soil–steel bridge had two closed pipe arches in its cross-section. The span of the shells was 4.40 m and the height of the shells was 2.80 m. The numerical analysis was conducted using the DIANA program based on the finite element method (FEM). The paper presents the FEM results of a 3D numerical study of a soil–steel bridge both with and without the application of the EPS geofoam under seismic excitations. The obtained results can be interesting to bridge engineers and scientists dealing with the design and analysis of bridges situated in seismic and mining areas.

Numerical analysis of a soil-steel bridge during backfilling using various shell models

Soil-steel bridges are becoming increasingly popular in various parts of the world, and are often built with a span of 3–25 m. Those with a span greater than 12 m are usually equipped with additional stiffening elements, e.g. ribs, relieving slabs, longitudinal beams, steel ribs and steel ribs filled with concrete. This paper examines the necessity of using these additional stiffening elements, using the example of a soil-steel bridge with a span of over 17 m. Stiffening steel ribs filled with concrete were used in this bridge, and the behaviour of the corrugated steel shell of the bridge was then analysed under backfilling loads. The DIANA program with the finite element method was used for the numerical analysis. The maximum displacements, bending moments and axial forces for the three numerical models of corrugated steel shell were considered, and the displacements obtained from numerical calculations were compared with measured results. In addition, the bending moments and axial forces obtained using finite element analysis were compared with results based on the relevant standards and design methods.

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

Abstract A 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.

The impact of backfill quality on soil-steel composite bridge response under seismic excitation

The soil-steel composite bridges, typically ranging from 3 to 25 m, can be used as an effective alternative for short-span bridges and culverts. They can meet the design and safety requirements as for traditional bridges, more rapidly and at lower costs. For these reasons, soil-steel bridges are increasingly being used in road and railway projects in many parts of the world. Due to the fact, the typical static and dynamic analyses of such bridges were already conducted many times, this paper focuses on the results of the numerical analysis of soil-steel composite bridge under seismic excitation. For these purposes a bridge with span of 17.67 m and height of 6.05 m was selected. Numerical analysis was conducted using the DIANA program based on finite element method. The density and Young modulus of the backfill were varied in the numerical models. A linear model with El Centro records and Time History analysis were used. The conclusions drawn from the study can be helpful for designers and researchers dealing with the soil-steel bridges, especially for the projects situated in the seismic areas.

The effect of mine induced tremors on seismic response of soil-steel bridges

Rockburst are similar phenomena like low intensity natural earthquake. They can be observed in Upper and Lower Silesia regions. Analyses of soil-steel bridges under seismic excitation are so far limited. The rockburst is related to the mining exploitation. The influence of rockburst on the soil-steel bridges should be investigated, because this ground motions differ with many respects from natural earthquakes. The span of soil-steel bridges is typically range from 3 to 25 m, so they can be used as an effectives alternative for a short-span bridges. The soil-steel bridges can meet the design and safety requirements similar to traditional bridges, at lower costs. For these reasons, soil-steel bridges are more frequently used in road and railway projects in many parts of the World. This paper presents results of numerical study of soil-steel bridge under rockburst induced ground excitations. Response characteristic axial of the soil-steel bridge caused by rockburts are analysed in detail. The obtained results are compared with the ones computed under El Centro using the seismic benchmark record.

Field Test of a Large-Span Soil–Steel Bridge Stiffened by Concrete Rings during Backfilling

Field Test of a Large-Span Soil–Steel Bridge Stiffened by Concrete Rings during Backfilling

Application of Results of Tests in Developing a Two-Dimensional Model for Soil–Steel Railway Bridges

This paper presents an analysis of the possibilities for the application of a two-dimensional model based on a circumferential strip of soil–steel structures that used results of measurements on railway soil–steel bridges. The distribution of a live load in the model was based on the so-called collocation point method. The method assumed conformity of results coming from a real test and those obtained in the two-dimensional model at a certain point of a structure. As a conformity criterion, deformation or internal forces (e.g., bending moment, thrust force, and stress) was assumed. Two locomotives moving above the structures were used to obtain influence lines of the collocation point. Examples of influence lines are presented; these also could be used for determination of stiffness of soil–steel bridges. The main advantage of this approach is the ability to evaluate the effects of any moving loads applied on existing bridges according to findings of measurements of deflections and development of deflection influence lines.

A soil-steel bridge under high-speed railways

This paper presents some recent research on railway bridge dynamics with application to buried flexible structures. Based on a combination of simulations and full-scale testing, current research in ...

Programming of geometry changes during construction of the soil-steel composite bridges

Programming of geometry changes during construction of the soil-steel composite bridges

Cathodic protection for soil-steel bridges

Cathodic protection for soil-steel bridges

Mechanical behavior of soil-steel structure subjected to live loads and different water conditions

The paper describes the analysis of a three-span soil-steel bridge along the road section crossing a dry anti-flood reservoir. The structure can be occasionally filled with water. The authors investigate internal forces and stresses in the shells due to live loads at different water conditions. Finite element simulations are carried out assuming elasticplastic behavior of soil, elastic shell and nonlinear (frictional) contact zone. The analysis takes into account soil load history. In particular, the construction and operation of the bridge under quasi-static live loads is considered. The construction stage includes laying and compaction of the backfill. Then, the bridge in operation is investigated at three different water conditions: normal use (dry reservoir), maximum water level (flood) and lowering of the water level in the reservoir. The results show that during the flood the maximum stress in the shell significantly increases. Moreover, some of non-linear effects, typical in such structures, e.g. hysteretic effect, become more evident in comparison to normal use of the bridge.

Static and fatigue performance of the bolt-connected structural jointed of deep corrugated steel plate member

Corrugated steel plate culvert bridge has been more commonly used as soil steel bridges because it is the cost-effective alternative for railway-highway crossings. The corrugated steel plate culvert bridge is considered the most suitable for quick rebuilding of bridges compared with the conventional bridges. This study intends to experimentally investigate the static and fatigue performance of the bolted connection of deep corrugated steel plate. Test variables are the thickness of deep corrugated steel plate and the types of bolted connection such as bolted-only, gasket, slot hole, and washer. For static test, the failure is mainly caused by a local buckling of deep corrugated steel plate member and bearing failure of bolts. Type of gasket and slot hole showed the largest stiffness so that they may be recommended for structural safety and redundancy under a static flexural behavior. For fatigue test, the bolted-only specimen exhibited no increase in the strain until failure and the highest fatigue life among the test variables. For structural safety under cyclic loading, bolted-only connection is recommended. According to AASHTO LRFD Bridge Design Specification, fatigue life category can be determined as category D level and the fatigue limit was estimated to be 48.3 MPa. The deep corrugated steel plate members tested in this study can provide a sufficient fatigue performance in compliance with the design specification.

GPR Investigation of Flexible Soil-steel Bridge Structure

Flexible soil-steel structures are commonly used due to its advantages including quicker construction process, lower cost of erection and maintenance, architectural values and others. However its behavior differs from classic rigid structures. It may be the reason why principles of soil-steel structures’ work are not always completely understood and lack of grasp may cause construction and design faults. To enable its detection and elimination non-destructive testing methods should be used. These methods are widely applied due to possibility of insight into inside of the completed structure. Nowadays, one of the most popular NDT methods is Ground Penetrating Radar method. It is commonly used in communication engineering for technical condition assessment of road and airfield pavements, railway embankments or bridge decks. To date this method is not widely used for flexible soil-steel structures’ inspections. This paper shows application of GPR method for SuperCor structure study. As a result of the research series of processed radargrams were obtained. They allowed to detect construction incorrectness of backfill layers and drainage elements. Presence of these anomalies may affect the sustainability which is dependent on the proper execution of drainage system. Case study presented in this paper may be helpful in determining reasons of incorrect behavior of soil steel structures during its exploitation what was repeatedly reported by road administrators.

Numerical analysis of soil-steel bridge

The paper presents a numerical analysis of the soil-steel bridge in the scope of static loads. The Abaqus program based on the FEM was used to calculations. Maximum displacements were obtained in the shell crown, and the largest stresses in the haunches. Calculation results were compared with the experimental ones and previous calculations obtained from the Robot Millenium program. The shapes of calculated displacements and stresses are similar to those obtained with the experiment, but the absolute values were generally higher than measured ones. Using both calculation programs, the relative reductions of displacement were in the range of 15–39%, and 17–44% for stresses in favour of the Abaqus program. Developed calculation model of the soil-steel bridge in the Abaqus program allows to obtain reasonable values of internal forces in the shell structure.

Numerical Simulation of Hysteretic Live Load Effect in a Soil-Steel Bridge

Abstract The paper presents numerical simulation of hysteretic live load effect in a soil-steel bridge. The effect was originally identified experimentally by Machelski [1], [2]. The truck was crossing the bridge one way and the other in the full-scale test performed. At the same time, displacements and stress in the shell were measured. The major conclusion from the research was that the measured quantities formed hysteretic loops. A numerical simulation of that effect is addressed in the present work. The analysis was performed using Flac finite difference code. The methodology of solving the mechanical problems implemented in Flac enables us to solve the problem concerning a sequence of load and non-linear mechanical behaviour of the structure. The numerical model incorporates linear elastic constitutive relations for the soil backfill, for the steel shell and the sheet piles, being a flexible substructure for the shell. Contact zone between the shell and the soil backfill is assumed to reflect elastic-plastic constitutive model. Maximum shear stress in contact zone is limited by the Coulomb condition. The plastic flow rule is described by dilation angle ψ = 0. The obtained results of numerical analysis are in fair agreement with the experimental evidence. The primary finding from the performed simulation is that the slip in the interface can be considered an explanation of the hysteresis occurrence in the charts of displacement and stress in the shell.