Over recent years, numerical simulations have arisen as the most effective method to analyze structures under blast events. However, in order to achieve accurate numerical predictions, reliable constitutive models contrasted against experimental benchmarks are needed. In this work, the experimental tests on normal and high-strength concrete slabs conducted by the University Missouri-Kansas City on the shock tube at the Engineering Research and Design Center, U.S. Army Corps of Engineers at Vicksburg, Mississippi, are modeled by using a novel constitutive model for concrete presented recently by the authors. The model makes extensive use of Fracture Mechanics considerations through the Cohesive Crack Model developed by Hillerborg and co-workers. The numerical predictions obtained show good agreement with the experimental results, especially in the case of the high strength concrete slabs.

Six normal and high-strength reinforced concrete slabs were subjected to simulated blast loading using a Blast Loading Simulator at the U.S. Army Corps of Engineers, Engineering Research and Design Center. A blind prediction contest was sponsored to evaluate the effectiveness of various modelling approaches to predict the blast response of the normal and high-strength concrete slabs. This paper describes a contest submission in the single-degree-of-freedom (SDOF) category generated using software program RCBlast. RCBlast was developed to perform inelastic analysis of structural members subjected to blast-induced shock waves. The program uses a lumped inelasticity approach to generate resistance functions for SDOF analysis. Incorporated into the development of the resistance functions were: material models and dynamic increase factors (DIF) appropriate for normal and high-strength concrete and steel reinforcement; member modelling capable of describing the gradual formation and progression of plastic behavior, and; hysteric modelling to account degradation in stiffness and energy dissipation.

Simulation of structural behavior of Reinforced Concrete (RC) subjected to shock loading is an important aspect of blast-resistant design of military and civilian structures. Depending on the application, different analytical approaches of varying complexities can be used to predict the nonlinear response of various concrete elements to blast loads. This paper reports the findings of a comprehensive study submitted for a Blast Blind Prediction Contest that involved various simulations of blast-loaded concrete slabs. The NSF in collaboration with ACI-447 and ACI-370 committees, Structure-Point and UMKC/ SCE sponsored the contest that included four categories requiring the use of Single Degree Of Freedom (SDOF) and physics-based (HYDROCODE) simulation techniques to predict the responses of one-way reinforced concrete slabs to two levels of blast loading. The study investigated the varying blast response characteristics associated with the use of two classes of concrete, Normal and High Strength and two classes of reinforcement, Normal and High Strength Vanadium. A testing program that encompasses all contest categories was completed at the Blast Loading Simulator (BLS) at the ERDC/ USACE, Vicksburg, MS to collect relevant shock loading and structural response data for various testing configurations. Various SDOF tools (i.e. P-I curves, UFC-3-340-02 charts, RCBlast, and RCProp/ SBEDS) and HYDROCODE constitutive models (LS-DYNA MAT-159, MAT-085, and MAT-072R3) were utilized to simulate various test setup information in order to predict maximum and residual responses and cracking patterns of tested RC slabs. Despite their major differences in modeling capabilities, analytical efforts, and inherent accuracy, all utilized simulation techniques were successful in predicting blast responses of investigated RC slabs with sufficient practical accuracy. Acknowledging their modeling limitations, SDOF simulations exhibited excellent capabilities in predicting overall behavior and maximum responses with a level of accuracy that is well suited for design applications. On the other hand, HYDROCODE simulations proved superior in their response and damage predictions owing to their modeling capabilities that allowed realistic end conditions, material nonlinearities, and strain-rate effects.

Numerical simulations of Reinforced Concrete (RC) panels subjected to blast loads are presented in this paper. In spite of a large number of events such as explosions and bombings in recent years, there is a difficulty in accurately predicting the behavior of structural systems due to blast loading. The effects of blast loads on 64” (L) x 33.75” (W) x 4” (H) RC slabs are studied using both nonlinear finite element analysis and Single Degree of Freedom (SDOF) models, and the analysis results are compared with available test results provided by the University of Missouri-Kansas City. This study investigated the gap between actual and predicted response of reinforced concrete structures subjected to highly dynamic loading such as blast. The effects of concrete strength, reinforcing steel grade, and the magnitude of blast loads on the dynamic response of reinforced concrete panels are considered.

A batch of blast resistance reinforced concrete slabs were tested in the shock tube facility at the University of Missouri Kansas City (UMKC). Based on the results from the tests, a blind numerical simulation contest was announced by UMKC in collaboration with the American Concrete Institute (ACI). The authors of this paper participated in the contest and received the test results only after completing their simulations. In this paper two basic numerical approaches are described. The first is a preliminary section rigidity assessment and the second is a full numerical simulation performed with the LS-DYNA code. The numerical results are compared with the UMKC test results and the influence of the numerical parameters is further discussed. The section rigidity assessment approach is then used to explain some unexpected results.