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Concrete panels are usually used to provide protection against incidental dynamic loadings such as the impact of a steel projectile. In this paper finite element technique is used to investigate the dynamic behavior and failure conditions of reinforced concrete panels subjected to the projectile impacts. Finite element model calibration was based on some experimental results conducted by M.E. Mohamed et al." Experimental Analysis of Reinforced Concrete Panels Penetration Resistance". Nonlinear three-dimensional numerical simulation of this experimental investigation was carried out using AUTODYNE, which is probably the most extensive code dealing with penetration problems. A comparison was conducted between the results calculated by the finite element method with field measurement and show relatively good agreement. The aim of this paper is to study numerically the penetration resistance of ferrocement panels reinforced with different number of layers and the main findings show an enhancement in the penetration resistance of about 30% with using ferrocement panels on other hand, the results showed that increasing number of layers of steel meshes have slight influence on the penetration resistance of these panels.

In this study, a circular cross-section tunnel with concrete lining is analyzed by the finite element code AUTODYN 3-D version 4.3., which is probably the most extensive code dealing with explosive loads in the world. First, a model calibration was performed for the AUTODYN finite element parameters and material models by using a field test problem with available field measurements. Then, based on the calibration results, a parametric study has been performed by means of finite element non-linear dynamic analysis to investigate the effect of underground explosion on the behaviour of circular tunnel with concrete lining in rock media. A charge of 2500 kg TNT was used as an explosive load. This charge was located at 3.25m-bellow ground surface with two crown-detonation distances 10 and 15m for all models. Finally, a non-linear rational analysis is conducted for the parametric study results to develop simple equations to determine peak displacements and strains for circular tunnels with concrete lining. These equations may help tunnel designers and military engineers in estimating displacements, and strains, then overall damage in the tunnels with no need to deal with complex finite element non-linear dynamic codes.

El-Azhar road tunnels, a major project of underground structures in Cairo, Egypt, were constructed by the tunneling boring machine (TBM). During construction of a proposed building over the existing El-Azhar road tunnels, Geotechnical challenges are expected to occur. An example of these challenges arises when the proposed building is constructed over the existing southern road tunnel. However, the serious damage in the road tunnel liners is predicted and the maximum radial displacement of the road tunnel is also computed. The allowable radial displacement of the road tunnel liners when the proposed building is constructed over the road tunnels should be checked within the allowable limit of 10 mm set by the Egyptian Standards. In the present study, the prediction of the impact of the proposed building construction on El-Azhar tunnels is highlighted and a model is proposed to study the soil structure interaction using a 2-D model of the proposed building on EI-Azhar tunnels. The study is conducted using Finite Element Method. The constitutive model for this analysis contains elasto-plastic materials. A yielding function of the Mohr-Coulomb type and a plastic potential function of the Drucker-Prager type are employed. A linear constitutive model is employed to represent the tunnel liners. The effects are expressed in terms of settlement and radial deformation in the road tunnels. The study includes the prediction of the settlement, the relative movements, and the lining stress under different loading steps. The description of the used model, the output results, and the final conclusion are presented in this paper.

Protective layers of fortified structures are considered key points in resisting missiles. Most of these protective layers are made from plain concrete. Due to the progressive development of military destructive weapons such as hyper-velocity missiles, plain concrete protective layers are not sufficient to resist the effect of hyper-velocity objects. So it is essential to have a new generation of protective layers to able to resist this kind of weapons. The objective of this paper is to enhance the protective layer material through designing a special concrete mixture with high reliability to resist the penetration of hyper-velocity object. Ferrocement technique is used to enhance the concrete panels' penetration resistance. A parametric study is performed on the effect of changing number of the steel wire mesh layers inside the concrete panels on its penetration resistance. The study in this paper is based on the finite element model verification conducted by M.E. Mohamed et al. using AUTODYN-3D on "Numerical Simulation of Projectile Penetration in Reinforced Concrete Panels" [1]. Also, plain concrete and ferrocement panels' penetration resistance was studied under the effect of hypervelocity objects. This Hyper-velocity projectile was presented in experimental work conducted by Dawson [2]. The main findings of this paper were that there is an enhancement in the penetration resistance for ferrocement panels rather than plain concrete once. Also increasing of steel layers mesh number have slight influence on the penetration resistance of the ferrocement panels.