Experimental Study on Behavior and Failure Mode of PSRC Bridge Pier under Close-In Blast Loading

Precast segmental reinforced concrete (PSRC) bridge piers have been widely used in bridges. Many experimental and numerical studies have been conducted to investigate the seismic and impact behavior of PSRC piers, but very limited effort has been completed on the blast resistance of PSRC piers. In this paper, reduced-scale field tests were performed on PSRC piers to study their behavior and failure mode under close-in blast loading, including one monolithic pier and 12 PSRC piers. The influences of some typical variables on the PSRC pier were investigated. Compared with the different failure modes between monolithic piers and PSRC piers under the bottom explosion, the experimental results show that the monolithic piers exhibit a localized flexural failure in the near explosion zone and numerous transversal cracks due to stress wave propagation vertically, while the PSRC piers show signs of localized punching shear failure at the bottom segment and vertical cracks due to concrete squeeze resulting from the relative rotation in other segments. Meanwhile, the PSRC pier with crushed concrete at the bottom segment collapsed completely under a smaller scaled distance. Under the middle explosion, the middle segments of PSRC piers experienced a flexural failure by showing bending deformation and concrete spalling. Through variable analysis, seven segments can reduce the localized residual deformation of the PSRC pier and small slenderness ratio can decrease the overall residual deformation of the PSRC pier. Shear key, ED bar, and the axial compression ratio of 0.1 can decrease the concrete damage including the concrete spalling and vertical cracks. Circular cross sections can effectively weaken the prestressing force loss due to small damage.

Automated summary

This study investigated the behavior and failure modes of PSRC piers under close-in blast loading through reduced-scale field tests. The results showed that PSRC piers exhibited specific failure characteristics compared to monolithic piers under different explosion conditions. It was found that by designing structural parameters such as the number of segments, slenderness ratio, and shear key, the localized and overall residual deformation of PSRC piers could be reduced effectively.