a large number of bridges and buildings that are currently used, are made of slabs with opening. some of these buildings and bridges have been severely damaged because of natural disasters such as earthquake, storm and other effects such as materials fatigue and alkaline and corrosive agents. therefore, retrofitting and strengthening of these structures is essential and affordable. in this rese...

Past earthquakes have demonstrated that old RC bridges may be seismically vulnerable. Bridge responses during the last decades illustrated the necessity of the seismic assessment of bridges especially those which were designed with old codes. In this research an existing concrete bridge representative of the most common bridges in the highway system in Iran are studied. Push over and nonlinear ...

The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the ty...

Many applications of imaging techniques like diffraction tomography demonstrate their ability to image the interior of huge structures like bridges. One problem of testing concrete bridges are grouting defects in tendon ducts which may lead to corrosion of tendons yielding a degradation of the stability of the whole structure. Ultrasound is able to penetrate the tendon ducts and therefore it ma...

The dynamic effect of moving vehicles on bridges is generally treated as a dynamic load allowance (or dynamic impact factor) in many design codes. Due to the road surface deterioration of existing bridges, studies have shown that the calculated impact factors from field measurements could be higher than the values specified in design codes that mainly target at new bridge designs. This paper de...

Using Unmanned Aerial Systems (UASs) for bridge visual inspection automation necessitates the implementation of Deep Convolutional Neural Networks (DCNNs) to process efficiently large amount data collected by UASs sensors. However, these networks require massive training datasets defects recognition and detection tasks. In an effort expand existing concrete datasets, particularly cracks in brid...

The purposes of this study were to investigate the seasonal variations in the relative permittivity of actual concrete bridge decks of various ages on Korea expressways, and to propose a practical way to calibrate two critical effects, to assess the condition of the concrete bridge decks with better accuracy. For these purposes, fifty-three actual concrete bridge decks on Korea expressways were...

Corrosion of reinforcement is a major problem affecting a large number of reinforced concrete structures. At present, most reliability-based design studies of reinforced concrete structures do not consider the effects of corrosion. In this paper, we present a reliability-based approach to the design of reinforced concrete bridge girders that are under corrosion attack. Both reserve and residual...