Comparison of Experimental and Analytical Load-Rating Methodologies for a Pony-Truss Bridge

Author(s):  
Timothy S. Schenck ◽  
Jeffrey A. Laman ◽  
Thomas E. Boothby
1977 ◽  
Vol 4 (2) ◽  
pp. 214-225
Author(s):  
Baidar Bakht ◽  
Paul F. Csagoly

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.


Author(s):  
Risa Fujinaga ◽  
Tatsumasa Kaita ◽  
Ryoko Koyama ◽  
Tsutomu Imai ◽  
Katashi Fujii

The load bearing capacity of an existing corroded pony truss bridge, which is used for 100 years was estimated from FEM results for whole bridge model. The beam element model is to clarify that the influence of the residual out-of-plane deformation in main truss structures on the load bearing capacity from the viewpoint of whole bridge. Also, shell element model is to clarify that the influence of severe corrosion damages occurred in many structural members on the load bearing capacity as whole bridge. On the other hand, the influence of assumed support conditions in analytical models were discussed from the analytical results of both type of models, because it will be thought that the performance of shoes deteriorates gradually by long in-service period. The ultimate load bearing capacity was estimated by the critical live load magnification. From the analytical results, the residual out-of-plane deformation of main truss structures in this bridge had little influence on the ultimate load bearing capacity. Also, the ultimate load bearing capacity may decrease up to 20% due to aging deterioration of shoes including corrosion damages. In bridge maintenance, it should be paid attention on local severe corrosion damages on the structural member, which may occur higher secondary stress.


1997 ◽  
Vol 2 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Thomas E. Boothby ◽  
Richard J. Craig
Keyword(s):  

Author(s):  
Chan Yang ◽  
Peng Lou ◽  
Hani Nassif

Many states have load rated their truss bridge gusset plates following the guidelines published in 2009 by the Federal Highway Administration in response to the catastrophic failure of the I-35W Bridge. As the Manual of Bridge Evaluation released new load rating provisions after 2014, the urgency in adopting and applying these mandated provisions became a pending burden for state agencies requiring extensive work to update the ratings of gusset plates. Moreover, this paper argues that the current states’ load rating practices do not involve the rating for the welded gusset plate owing to the lack of established provisions. In addition, the gusset plate with no plans also poses particular challenges for the state agencies. To provide state agencies with better insights on the load rating approach of gusset plates, this paper presents a study that carefully reviewed the states’ current practices and load rating provisions. The results of the study indicate the necessity of adopting the new provisions, as the former load rating methodology exhibited inaccurate results in some cases. Additionally, this paper reviews extensive work done for welded connections and proposes a load rating guidance for welded gusset plates. To deliver better interpretations, a case study is provided for the welded gusset plates. This paper also reviews the evaluation method for deteriorations and staggered bolt patterns with relevant case studies. Lastly, the paper provides guidance on estimating the unknown bolt strength as well as weld metal strength for the gusset plate.


2001 ◽  
Vol 85 (8) ◽  
pp. 76-81
Author(s):  
Holger S. Svensson ◽  
Markus Maier
Keyword(s):  

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