Towards actual brazilian traffic load models for short span highway bridges

Abstract

New live load models for highway bridge design in Brazil are under development by assembling real traffic database, traffic simulations, analytical-numerical modeling of the dynamic interaction between vehicle and structure and statistical extrapolations. This paper presents and discusses the results obtained in the first stages of this work which includes the comparison between the static effects due to the actual traffic of heavy vehicles and those generated by the live load model given in the current national code NBR 7188. It is demonstrated that this live load model is not appropriate to represent the actual traffic effects and may be, in some cases, non-conservative. The present work deals with short span bridges for two lanes single carriageway under free flow traffic scenarios. The representative static effects in these bridges due to the actual traffic of heavy vehicles are obtained by extrapolating its probability density functions to a certain return period. To this purpose, a traffic database was constructed by gathering data from several weighing stations in Brazilian highways which was then applied to perform traffic simulations through a specially developed computational tool.

Fatigue design in reinforced concrete bridges according to Brazilian code

“…Third, according to the results, the freight vehicles with 5, 6, 8 and 9 axles were those that presented the higher stress variations in all studied beams of all bridge models, therefore, being those that tend to cause more deleterious effects compared with the others analyzed. These results lead to similar conclusions that have been found in previous studies, such as Pircher et al (2011) and Rossigali et al (2015). Moreover, if this analysis was performed, taking into consideration the data from the three toll collection points, roads with a huge volume of those vehicles deserve attention.…”

“…Brazilian authorities and governmental bureaus do not have a clear understanding and sufficient information about the real and current situation of these structures (Mascarenhas, Carvalho, Vitório, 2019). Rossigali et al (2015) point out that the current Brazilian live load model to design bridges (ABNT, 2013) does not represent the current traffic effects properly, and it can be in certain situations against security.…”

Analysis of the brazilian federal bridge inventory

“…Typical cross-section of Brazilian bridges code NBR 7188/2013 [18] raises another concern. The simulation showed that Brazilian code load models may not adequately reproduce the real traffic of heavy vehicles and may, in many cases, be non-conservative [19].…”

Global‐local fatigue assessment of an ancient riveted metallic bridge based on submodelling of the critical detail

“…Strain ranges and number of cycles causing by single truck across the bridge are obtained by using the rain‐flow counting. The annual damage index can be derived according to Equation in comprehension with the damage index due to single truck and traffic statistical results, where the average daily volume being 6000 is adopted according to research by Rossigali et al Assuming that failure occurs when the cumulative damage exceeds 1, fatigue lives of concerned joint based on the strain states around the rivet holes are determined, as listed in Table . The predicted lives of the regions around the riveted hole are longer than 50 years expect for the region around the Hole 15, indicating that in the gusset plate are much more prone to fatigue failure and needs to be strengthened for insufficiency.…”