Strengthening and widening of steel pony truss bridges

1977 ◽  
Vol 4 (2) ◽  
pp. 214-225
Author(s):  
Baidar Bakht ◽  
Paul F. Csagoly
Keyword(s):  
Traffic Safety ◽  
Carrying Capacity ◽  
Point Of View ◽  
Load Carrying Capacity ◽  
Truss Bridges ◽  
Load Carrying ◽  
Live Loads ◽  
Pros And Cons ◽  
Pony Truss Bridge ◽  
Truss Bridge

There are many thousands of existing pony truss bridges in North America which were constructed in the earlier part of this century and are still serving as important traffic carriers. The present economic situation demands that these bridges should usefully serve their purpose for as long as is safely possible.These bridges could be found inadequate for either or both of the following reasons. With the exception of remote areas, operational traffic safety would require two 12-ft lanes plus adequate shoulders. Many of these old bridges are therefore unsatisfactory from the geometrical point of view. Some bridges were designed for live loads that are only a fraction of present commercial vehicle weights.A computer-oriented method of rigorous analysis of lateral buckling behaviour of pony truss bridges is briefly discussed. The method is implemented through a computer program which has been validated by experimental data. It is expected that the program would predict realistic values of load-carrying capacity of such bridges and would help to avoid many an unnecessary replacement.Various methods of strengthening and widening pony truss bridges, and their pros and cons, are discussed. It is shown that the strengthening of a few components of a pony truss bridge does not always lead to an increase in the load-carrying capacity of the bridge.

Unusual Composition and Load-Carrying Capacity of a 100-Year Old Early Age Steel Exposition Hall

2020 ◽  
Author(s):  
V. Bogaert
Keyword(s):  
Carrying Capacity ◽  
Point Of View ◽  
Early Age ◽  
Load Carrying Capacity ◽  
Main Structure ◽  
Load Carrying ◽  
The World ◽  
World Exposition ◽  
Structural Point

<p>The Floraliahall in Ghent was built during 1912-1913 as part of a series of large infrastructure works for the world exposition of 1913. The main structure of the hall consists of 18 portal frames having 3 spans of 10.16, 40.18 and 10.16 m. The upper part of the structure is highly slender. Adversely to the customary concepts of 100 years ago, the lighter frames at 7.45 m distance, are hinged twice at the springs, whereas the more heavy frames, at 15 m distance, are completely clamped at their base. In addition, measurements show that crosssections of compressed parts have larger area than the tensile parts. From the structural point of view, these frames sometimes have an unexpected composition. The aim was to determine whether this structure can comply with contemporary requirements and codes. From measurements and simulations follows that in limited areas high stresses appear, unacceptable even in serviceability state. This may be partly due to modifications of the roof that were made inappropriately, from the uncertainty to assess certain details with the model and from ineffective analysis at the time of construction.</p>

scholarly journals A Study on the Performance of a Magnetic-Fluid-Based Hydrodynamic Short Journal Bearing

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
N. S. Patel ◽  
D. P. Vakharia ◽  
G. M. Deheri
Keyword(s):  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Fluid Pressure ◽  
Point Of View ◽  
Graphical Form ◽  
Load Carrying Capacity ◽  
Additional Degree ◽  
Load Carrying

Efforts have been made to study and analyze the performance of a hydrodynamic short journal bearing under the presence of a magnetic fluid lubricant. With the usual assumptions of hydrodynamic lubrication, the associated Reynolds equation for the fluid pressure is solved with appropriate boundary conditions. In turn, this is then used to calculate the load-carrying capacity which results in the calculation of friction. The computed results presented in graphical form suggest that the bearing system registers an improved performance owing to the magnetic fluid as compared to the conventional lubricant. It is clearly observed that the load-carrying capacity increases nominally while the coefficient of friction decreases significantly. Besides, it is seen that the bearing can support a load even when there is no flow of lubricant. In addition, this type of study may offer an additional degree of freedom from design point of view in terms of the forms of the magnitude of the magnetic fluid.

scholarly journals Techniques d'assemblage permettant de placer les sciages feuillus sur le marché de la construction | Joining Techniques to Introduce Hardwood Timber into the Construction Market

2000 ◽  
Vol 151 (7) ◽  
pp. 257-261 ◽  
Author(s):  
Adrian Mischler
Keyword(s):  
Carrying Capacity ◽  
Decisive Factor ◽  
Load Carrying Capacity ◽  
Construction Market ◽  
Load Carrying ◽  
Pros And Cons ◽  
Timber Engineering

Joining techniques are a decisive factor for the performance of load-carrying structures in wood constructions. They must meet the following static requirements: load carrying capacity,rigidity and ductility. The most frequently used joining techniques for load-carrying structures in wood constructions are presented and their pros and cons are commented on. The performance of spruce and ash timber have been compared using connections of GLT beams assembled in accordance with BSB technique. These tests have shown that hardwood reaches a higher performance than softwood in such applications. Thanks to innovative joining techniques, hardwood reaches new fields of utilisation in modern timber engineering.

Bridges Tested to Failure in Sweden

2018 ◽  
Author(s):  
Björn Täljsten ◽  
Thomas Blanksvärd ◽  
Gabriel Sas ◽  
Niklas Bagge ◽  
Jonny Nilimaa ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
The Real ◽  
Existing Structures ◽  
Steel Truss Bridge ◽  
Standard Code ◽  
Load Carrying ◽  
Existing Bridges ◽  
Truss Bridge

Five bridges of different types have been tested to failure and the results have been compared to analyses of the load-carrying capacity using standard code models and advanced numerical methods. The results may help to make accurate assessments of similar existing bridges. There it is necessary to know the real behaviour, weak points, and to be able to model the load-carrying capacity in a correct way.<p> The five bridges were: (1) a strengthened one span concrete road bridge - Stora Höga ; (2) a one span concrete rail trough bridge loaded in fatigue – Lautajokk; (3) a two span strengthened concrete trough railway bridge - Övik; (4) a one span railway steel truss bridge -Åby; and (5) a five span prestressed concrete road bridge - Kiruna. The unique results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy and shortcomings/potentials of different codes and models for safety assessment of existing structures.

Load-Carrying Capacity of the early age Steel Ghent Floralia Exposition Hall/Tragverhalten der Floralia-Ausstellungs- halle des frühen Stahlzeitalters

Bauingenieur ◽  
2020 ◽  
Vol 95 (05) ◽  
pp. 174-179
Author(s):  
Philippe Van Bogaert
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Point Of View ◽  
Early Age ◽  
Load Carrying Capacity ◽  
Main Structure ◽  
Load Carrying ◽  
The World ◽  
World Exposition ◽  
Structural Point

ABSTRACT The Floraliahall in Ghent was built during 1912 and 1913 as part of a series of large infrastructure works for the world exposition of 1913. The main structure of the hall consists of 18 portal frames having three spans of 10.16 m, 40.18 m and 10.16 m. The upper part of the structure is highly slender. Adversely to the customary concepts of 100 years ago, the lighter frames at 7.45 m distance, are hinged twice at the springs, whereas the more heavy frames, at 15 m distance, are completely clamped at their base. In addition, measurements show that cross-sections of compressed parts have larger area than the tensile parts. From the structural point of view, these frames sometimes have an unexpected composition. The aim was to determine whether this structure can comply with contemporary requirements and codes. From measurements and simulations follows that in limited areas high stresses appear, unacceptable even in serviceability state. This may be partly due to modifications of the roof that were made inappropriately, from the uncertainty to assess certain details with the model and from ineffective analysis at the time of construction. ZUSAMMENFASSUNG Die Floraliahalle in Gent wurde zwischen 1912 und 1913 als Teil einer Reihe großer Infrastrukturarbeiten für die Weltausstellung von 1913 errichtet. Die Hauptstruktur der Halle besteht aus 18 Portalrahmen mit drei Feldern von 10,16 m, 40,18 m und 10,16 m. Der obere Teil der Struktur ist sehr schlank. Im Gegensatz zu den vor 100 Jahren üblichen Konzepten sind die leichteren Rahmen in einem Abstand von 7,45 m gelenkig aufgelagert, während die schwereren Rahmen in einem Abstand von 15 m vollständig an ihrer Basis eingespannt sind. Außerdem zeigen Messungen, dass Querschnitte von druckbeanpruchten Teilen eine größere Fläche aufweisen als die Zugteile. Vom strukturellen Standpunkt aus haben diese Rahmen manchmal eine unerwartete Zusammensetzung. Ziel war es festzustellen, ob diese Struktur den heutigen Anforderungen und Normen entspricht. Aus Messungen und Simulationen geht hervor, dass in begrenzten Bereichen hohe Beanspruchungen auftreten, die auch im Gebrauchstauglichkeitszustand nicht akzeptabel sind. Dies kann zum Teil auf unsachgemäß vorgenommene Änderungen des Daches, auf die Unsicherheit, bestimmte Details mit dem Modell zu bewerten, und auf eine ineffektive Analyse zum Zeitpunkt des Baus zurückzuführen sein.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala
Keyword(s):  
Fuzzy Sets ◽  
Carrying Capacity ◽  
Stochastic Methods ◽  
Nonlinear Behaviour ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Input Parameters ◽  
Stochastic Solution ◽  
Fuzzy Solution ◽  
Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

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