Since the September 11, 2001, attack in New York, the number and intensity of terrorist activities around the world have attracted our attention toward infrastructure systems. Also, unintentional explosions resulting from fuel oil (gas) and fireworks in transit can lead to the interruption of the highway system. In addition, crucial bridges in a local war are main targets for hostile forces because they convey military supplies. Bridge piers are main axial bearing components and readily suffer damage under blast loading, so damage modes of bridges in different cases and explosive damage assessments should be studied to provide design advice for protection against explosion. In this paper, numerical models of reinforced concrete (RC) piers are built and verified by the explosion experimental acceleration data and the theoretical ultimate bearing capacity. Based on the verified model, different damage modes of RC piers in three noncontact explosive cases are investigated, in which the locations of explosive centers are at the bottom, the midheight, and the top of the pier. RC piers always experience flexural failure in these cases. The residual bearing capacities of piers before collapse are also studied, and the relations between trinitrotoluene (TNT) mass and residual bearing capacity are fitted by a cubic polynomial, resulting in a downward trend. From damage index and polynomial, the damage extent after blasting can be evaluated.

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.

Since the 9.11 attacks in New York, terrorist attacks, military strikes, and accidental explosions have caused serious damage to various infrastructures around the world. Accidental traffic explosions in bridge engineering have occurred frequently due to the increasing firework truck on the bridge and heavy fuel oil ships under the bridge. Besides, intentional car bomb explosions in terrorist attacks and military assaults are significant threats to the bridge structure. Bridge pier is a particularly important component of the overall bridge structure due to its vertical support capacity. Therefore, the damage of reinforced concrete (RC) piers under blast loading should be studied. In this paper, the pier is simplified as a single degree of freedom (SDOF) system based on energy equality, and the blast loading distribution on the surface of the pier is simplified as a uniform distribution. Then, the P‐I curves of an RC pier are obtained based on the SDOF system and a uniform distribution blast loading to quickly evaluate the damage extent of an RC pier so that the P‐I curves and fitting formulas for different damage extents can be used for practical engineering. After a numerical simulation verification, the P‐I curves and fitting formulas based on the simplified method can supply a rapid and effective method for engineers to assess the postexplosive damage of an RC pier.

In simulating engineering structures, the uncertainty quantification and propagation (UQ&P) of model parameters is of paramount importance for model verification and validation (V&V), the fidelity of which has been proven to have a prominent effect on structural safety assessment and decision making. In this study, the parametric uncertainties due to environmental periodicity were inversely quantified in form of intervals through a V&V framework based on the conjunction of interval response surface method (IRSM) and probability box (P-Box), which is adaptable and efficient for real bridge structures. The uncertainties of temperature were first quantified with P-Box, based on a year’s worth of data obtained from the structural health monitoring (SHM) system of a cable-stayed bridge. Following that, the uncertainties of structural frequencies were quantified through a correlation analysis between temperature and frequencies which were filtered by different techniques. The expressions of IRSM were constructed and verified, with frequencies calculated from them agreeing well with those calculated from the finite-element (FE) model simulation. Thereafter, the interval boundary values of the observed frequencies were obtained by searching the tails of the P-Box bounds, thus providing the target intervals for model validation. The parametric intervals were validated efficiently through a two-step calibration procedure based on monotonic analysis. The result shows that the validated model has a good predictive capacity and could serve as a high-fidelity model for further application, with the parametric uncertainties appropriately considered in the form of intervals.