A typical blast wave attenuation curve presents a relationship between Peak Particle Velocity (PPV) at the surface of a geologic profile and distance. As the stress wave is amplified at the free-field boundary, the attenuation curve at the surface is always larger than the within media profile curve. Measurements are made at the rock's surface and test blasts are always conducted to ensure the safety of underground existing structures. In order to design underground blasting, the recorded PPVs are then reduced by a factor of 2. In this paper, particle velocity amplification was studied by using numerical simulation, and the difference between PPV at the surface and within media profiles is quantified. The amplification factor depends upon source depth, incidence angle, and Poisson’s ratio of the media. It is calculated as the ratio of the magnitude of PPV at the surface of the media to the within media profile. According to the parametric study, the amplification factor for a uniform medium increases with increasing source depth, while the amplification factor decreases with increasing Poisson’s ratio. Considering a three-layer model with a source depth of 30m, the amplification factor is high for low incident angles and low for higher incident angles. The range varies between 1.5 to 2.1.

Shear strength is a crucial parameter in designing Reinforced Concrete (RC) columns considering the effects of lateral loads such as wind or earthquakes. Numerous design codes and published studies have proposed equations for calculating the shear strength of RC columns. However, a discrepancy exists between the calculated models and the experimental results. The aim of this study is to evaluate the calculated models for the shear strength of rectangular RC columns based on 735 data sets, obtained from the literature. Six code-based and empirical models are investigated in this paper. The four code-based models include ACI 318 (2014), CSA (2014), Eurocode 8 (2005), and FEMA 273 (1997), and the two empirical models are proposed by Ascheim & Moehle (1992) [8] and Sezen & Moehle (2004) [9]. The shear strengths of RC columns are calculated for the six models using inputs from the experimental database. Finally, the results are evaluated using statistical indicators, including coefficient of determination and root-mean-squared error. The results reveal that Eurocode 8 (2005) is the best model, followed by Sezen & Moehle (2004) and Canada CSA (2014) since the results of those models are close to the experimental ones and shown to be more conservative than the others.