Masonry barrages are considered one of the most important water structures in Egypt. They control water levels in the River Nile and its branches and canals. It is very important to keep them working in good condi tion to assure good water management and distribution process. Most of barrages in Egypt have been built many years ago using masonry bricks without steel reinforcement. Due to their importance it is essential to protect these structures from the risk of earthquakes. Also some of these masonry barrages have been belt hundreds years ago and still working till now. The new barrages in Egypt were built using reinforced concrete. The cost of reinforced concrete structures is much higher than masonry structures. The main problem of the masonry structures is their low resistance to lateral load especially in the out of plane direction which causes over stress in the barrage piers during earthquakes. This research was performed to investigate the effect of us ing reinforcement masonry and prestressed masonry to increase the seismic load capacity of barrage piers in the out of plane direction. These two techniques could be used in new structures or in existing structures. Three masonry piers were built on a s haking table using ordinary masonry, reinforced masonry, and pre-stressed masonry. These piers were exposed to cyclic loads with different frequencies to model the earthquake. Finite element model was developed for the tested piers. Dynamic analyses were performed using the same input motion of the shaking table. The results of the experimental and the numerical models were compared to adjust the numerical model. Another finite element models were developed for typical masonry barrage using ordinary and re inforced masonry. Time history dynamic analyses were performed to investigate the effect of earthquakes on their responses. Guidelines for the assessment of the use of reinforced and pre-stressed techniques in construction and strengthening of masonry barr ages were suggested.

Some structures are exposed to blast load due to different reasons such as; quarry blasting, explosions used in the construction of new roads, bomb, terrorist attack, or other artificial explosions. Ground vibrations are part of the output of the blasting operations. When their levels are high, they can cause damage to nearby structures. For example; cement companies has been in operation long time ago in some areas in Egypt using quarry blasting. Since then, new structures and new communities were established in these areas and some nearby structures were damaged due to ground vibrations (such as; some buildings in the 15 th of May city). The reduction of the additional stress in the structures is necessary for the safety of the existing structures near the bl ast because even a small amount of blast can produce a serious damage to the structures. Most design codes have specified for the seismic vulnerability and also against vehicular collisions but there are no definite structural design criteria for the struc tures exposed to typical blast loadings. This research is intended to investigate the effect of blast load on a water structure (barrage) when using open trench as low-cost barrier to reduce the internal forces induced in the structure during the blast. T he barrage structure was chosen in this research because this type of water structures is of special importance in Egypt since they control the water management process. The analysis of these structures should be carried out for different loading condition s. They are normally designed for dead load, live load and other occasional loads. To investigate the effect of blast load on the structure (with and without using trench), Finite element analysis model under dynamic load (blast load) has been established for the structure. Non-linear dynamic time history analysis was performed for the structure without using trench. Then, an open trench was used as a wave barrier to reduce the effect of the ground vibrations induced by the blast on the internal forces of the structure. A parametric study was carried out to investigate the effect of different factors affecting the internal forces induced in the structural elements due to blast load such as; depth, width, and location of the trench. These factors are import ant for the safety of structures near the blast.

There are a lot of bridges in Egypt; most of them are used to cross the River Nile or its branches and also to cross the streets to reduce the traffic jam. Due to some problems in the bridge itself or in the road after the bridge, it is required to reduce the velocity of vehicles on the bridge. In many cases obstacles are constructed on the bridge to reduce the velocity of the vehicles. These obstacles cause impact forces in the structural elements of the bridge. Also, due to the rough pavement or due to the bad maintenance of the expansion joints, the impact forces happen when the vehicles pass over the bridge. In this research the vibration responses of a typical R.C bridge, due to truck passing an obstacle on the bridge, were measured using accelerometer transducers connected to a data logger system. Signal processing operations were carried out on the recoded signals to enhance the data quality and to obtain the velocity and displacement from the acceleration response. Finite element model was developed for the bridge to evaluate the effect of vibration. The numerical model was subjected to the real recorded signals (displacement response). The stresses due to these vibrations were calculated and compared to the original stress of the bridge due to static loads. Then, an oscillator beam model was used to model the bridge, the obstacle, and the truck taking into consideration the interaction between them. The results of this model were compared to that obtained from the measured response to assure that the stresses due to the experiment are matched with that obtained from the oscillator beam model. Then a parametric study was performed to study the effect of the obstacle height, the wheel load, and the span of the bridge on the results. The impact factor obtained from the Egyptian Code for Loads was compared to that obtained from the numerical results to investigate the excessive stresses induced in the bridge due to the existence of an obstacle on the bridge. As a result of this study, recommendations and guidelines were suggested.

This paper studies the effect of wave loads on the submerged piles. The submerged piles are used widely in harbors, and offshore structures.The bottom part of the pile is buried in soil under the mud line while the upper part (free height of the pile above the mud line) is subjected to waves. The internal forces induced in the pile depend on many factors such as, pile diameter, soil type, water depth, wave period and height. A numerical model for a submerged pile was developed using a commercial Finite Element program to study the internal forces induced on submerged piles which subjected to wave action. The factors affecting the internal forces induced in the pile, due to the wave load, were studied. In the present research, range of different values for each factor was taken into consideration to establish the effect of each factor on the internal forces induced in the pile. The results were summarized in curves to highlight the effect of each factor.

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