This CD-ROM contains 15 papers that were presented at sessions sponsored by ACI Committees 447 and 370 at the ACI Fall 2010 Convention in Pittsburgh, PA. In this publication, engineers report on how they are approaching the challenging task of predicting the response of structures subjected to blast and impact loading. Both experimental and analytical efforts are represented, often in tandem. The analytical approaches taken include single-degree-of-freedom modeling, highly nonlinear transient dynamic finite element simulations, and coupled Lagrangian-Eulerian simulations. Papers in the publication cover the design and evaluation of new and existing structures, as well as techniques for strengthening existing structures. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-281

The lack of a complete understanding of shear behavior under high dynamic conditions hindered the efforts for accurate prediction of impact behavior, since severe shear mechanisms may dominate the behavior of RC structures when subjected to impact loads. This current study involves a well-instrumented experimental program that was undertaken to contribute to our understanding of the effects of shear mechanisms on the behavior of reinforced concrete (RC) structures under impact loads. The test results showed that the shear characteristics of the RC beam specimens played an important role in their overall behavior. All specimens, regardless of their shear capacity, developed severe diagonal shear cracks, forming a shear-plug under the impact point. Furthermore, the application of the Disturbed Stress Field Model (DSFM) as an advanced method of modeling shear behavior under impact conditions is also investigated. A two-dimensional nonlinear finite element reinforced concrete analysis program (VecTor2), developed previously for static loads, was modified to include the consideration of dynamic loads such as impacts. VecTor2 analyses of the test specimens were satisfactory in predicting damage levels, and maximum and residual displacements. The methodology employed by VecTor2, based on the DSFM, proved to be successful in predicting the shear-dominant behavior of the specimens under impact.

Fiber reinforced concrete (FRC) is known to exhibit superior performance in its post-peak energy absorption capacity, (i.e., toughness) under flexural and tensile loading. However, the behavior of fiber reinforced concrete under compressive impact has not previously been investigated. In the present research, the strain rate response of fiber reinforced concrete under compressive impact was investigated over the full strain rate regime, from static loading to high strain rate loading, and finally to impact loading. FRC was found to have higher strengths under compressive impact loading than under static loading. The compressive toughness under impact loading increased due to the high peak load and the high strain capacity. FRC displays a much higher Dynamic Improvement Factor (DIF) under compressive impact and provides an overall higher performance under impact than under static loading. Finally, the existing CEB model for dynamic behavior of concrete was evaluated and a new constitutive model, the RCM modelis proposed to describe the DIF of the compressive strength of FRC. The model was found to match the test results for FRC at 50 MPa, 90 MPa, and 110 MPa (7250, 10,150 and 13,000 psi) at strain rate from 10-5 1/sec to the strain rate of 10 1/sec.

This paper presents a rational method to design barrier systems subjected to vehicular impact loading. The method is based on the energy principle using vehicle characteristics. It covers barrier systems with stiffness ranging from rigid to both linear elastic and nonlinear systems subjected to various vehicular speeds. A comparison of the analytical method with test data shows reasonable correlation.

Using a shock tube to subject structures to shock wave loading is a safe, economical and reliable alternative to live explosive testing. The University of Ottawa shock tube testing facility is capable of simulating shock wave induced loading of structures subjected to high explosive blast. The shock tube can accurately generate shock waves with similar properties as those produced by the actual detonation of high explosives. The parameters of the shock waves generated by the shock tube are found to be a function of driver length and driver pressure. Pressure-time histories are found to be in good agreement with similar free-air detonations. Furthermore, shock waves are found to be planar at the testing frame. Blast induced testing of structural elements, such as columns, slabs and masonry walls have been subjected to shock wave induced loading. This paper outlines the parameters of shock tube induced shock waves and explores the benefits of shock tube testing over live high explosive testing.