The need of high performance concrete HPC is increasing in the recent years. This material becomes necessary, but it is brittle. So, fibers are used to enhance mechanical properties of HPC. The enhanced properties include tensile strength, compressive strength, elastic modulus, crack resistance, crack control, durability, fatigue life, resistance to impact and abrasion, shrinkage, expansion, thermal characteristic, and fire resistance of concrete. The main objective of this research is to study the effect of using Harex, polypropylene and glass fibers on flexural behavior of High performance concrete beams under static and repeated loads.

The need of high performance concrete HPC is increasing in the recent years. This material becomes necessary, but it is brittle. So, fibers are used to enhance mechanical properties of HPC. The enhanced properties include tensile strength, compressive strength, elastic modulus, crack resistance, crack control, durability, fatigue life, resistance to impact and abrasion, shrinkage, expansion, thermal characteristic, and fire resistance of concrete. The main objective of this research is to study the effect of using Harex, polypropylene and glass fibers on flexural behavior of High performance concrete beams under static and repeated loads.

The elevated cylindrical storage silos are lifeline structures and strategically very important, since they have vital use in industries. Silos are special structures subjected to many different unconventional loading conditions, which result in unusual failure modes. In addition silos are cantilever structures with the material stacked up very high vertically. The earthquake response of silo structures for the storage of bulk solids differs for elevated silos and silos supported directly on the ground. The walls of different type of silos are subject to earthquake loads from the stored mass, and these may substantially exceed the pressures from filling and discharge. The assessment of horizontal action of ensiled material due to seismic vent seems to be particular interest. This paper is concerned with the earthquake response of these structures, which has received little attention to date. A cylindrical silo wall and bulk solid is modeled by three dimensional finite solid elements. The interaction effect between the silo wall and bulk solid is taking account by using the nonlinear approach proposed by Duncan and Chang [5]. A then interface layer proposed by Desia [4] is applied to describe the phenomena taking place on the surface between the granular material and silo wall. Coulomb's friction low was used for modeling of wall friction. An incremental iterative finite element technique is applied for dynamic analysis of wheat silos using SAP2000 structural software package [3]. In this research seven reinforced concrete silo models with different height to diameter ratios were studied and analyzed in time history by using earthquake acceleration 0.5g applied to silos models. The resulting finite element silo pressures as the silo is full with and without earthquake excitation are compared with theoretical filling and discharging pressure. The result obtained revealed that the elevated silos response is highly influenced by the earthquake characteristics and is depending on the height to diameter ratio. Also the findings indicate that the squat silos (large diameter to height ratio ) are more resistance to the earthquake and more economical. The seismic responses of the elevated wheat silo such as top displacement, normal forces, shearing forces and bending moments in silo support have been assessed for earthquake records.

Frame system structures which composed of only reinforced concrete columns, beams and slabs, have been widely adopted for many framed buildings. Generally, in-plane stiffness of slabs is ignored in the conventional analysis of such structures. However, in reality, the floor slabs may have some influence on the lateral response of the structures. Consequently, if the in-plane stiffness of slabs in a frame system structure is totally ignored, the lateral stiffness of the global frames may be underestimated. Therefore, the objective of the research is to investigate the effect of floor diaphragms in multi-story frames by comparing frames models with different slabs thickness by those without slabs. Furthermore, it can be seen from the study that the slab thickness is an important factor increasing in-plane stiffness of the slab and consequently increasing the overal in-plan stiffness of the building leading to an increase in base shear and a decrease in lateral displacements values.

Helical piles have been used widely in engineering application .They can be used to provide structural stability against axial compression ,uplift and lateral forces. . In recent years, helical pile foundations have become more widely used in many countries. There are few studies about helical piles, for this reason the aim of the present paper is to study how to improve the prevision of the compression and uplift capacities of helical piles, and study the effect of embedded depth and helical area of helical piles in sand soil on the compression and uplift bearing capacities. Studies of helical piles with different areas of helices provided are in continuation. Compression and uplift loads were applied at different height within the soil. The embedment length of screw anchor piles was also varied to study the behavior of helical piles under compression and uplift loads. Various size and numbers of helices have been used in the laboratory tests with diameters 5 ,6.7 , 8.2 and 10cm with varying lengths. The embedment ratios for each ,D/d are 1 ,2 ,3 ,4 ,5 ,6 and 7 . An experimental setup instrumented to allow the measurement of the compression and pullout loads which affect on the helical pile installed into prepared layers of sand until failure. The results show that the compression and pullout resistance of helical anchors is strongly affected by the area and composition of helical plates welded to the pile steel shaft . The compression and uplift loads are increased with increasing of the embedment ratios, D /d and helix diameter, d. In addition to some other useful results are indicated in this paper.

Helical piles have been used widely in engineering application .They can be used to provide structural stability against axial compression ,uplift and lateral forces. . In recent years, helical pile foundations have become more widely used in many countries. There are few studies about helical piles, for this reason the aim of the present paper is to study how to improve the prevision of the compression and uplift capacities of helical piles, and study the effect of embedded depth and helical area of helical piles in sand soil on the compression and uplift bearing capacities. Studies of helical piles with different areas of helices provided are in continuation. Compression and uplift loads were applied at different height within the soil. The embedment length of screw anchor piles was also varied to study the behavior of helical piles under compression and uplift loads. Various size and numbers of helices have been used in the laboratory tests with diameters 5 ,6.7 , 8.2 and 10cm with varying lengths. The embedment ratios for each ,D/d are 1 ,2 ,3 ,4 ,5 ,6 and 7 . An experimental setup instrumented to allow the measurement of the compression and pullout loads which affect on the helical pile installed into prepared layers of sand until failure. The results show that the compression and pullout resistance of helical anchors is strongly affected by the area and composition of helical plates welded to the pile steel shaft . The compression and uplift loads are increased with increasing of the embedment ratios, D /d and helix diameter, d. In addition to some other useful results are indicated in this paper.

This research studies the effect of abnormal operation conditions on water hammer phenomenon in water supply pipe network in order to provide an acceptable level of protection against system failure due to pipes collapse or bursting. Water Hammer and Mass Oscillation WHAMO software is used in the analysis which uses the implicit finite difference scheme for solving the momentum and continuity equations at unsteady state case. Assiut city water supply network is used in the analysis. Flow of pipe network is studied due to; firstly, the sudden change in water demand at one or more junctions, secondly, the closing of some pipes of the network on the transient pressure and flow rates, and finally the failure in some network pipelines on intrusion or leakage due to transient pressure head fluctuations. The previous cases are studied in steady normal case, without any protection, and under different protection device(s) such as non-return valve and open surge tank. The results showed that rapidly change in demand increases the pressure head and flow rate fluctuations. Closing some pipelines increases pressure in a region and decreases it at another and also changes the direction of flow in the network. Also, failure of some pipelines can cause intrusion and leakage from outside the network to inside and inversely, which affects the values of minimum pressure heads more than the maximum ones

This research studies the effect of abnormal operation conditions on water hammer phenomenon in water supply pipe network in order to provide an acceptable level of protection against system failure due to pipes collapse or bursting. Water Hammer and Mass Oscillation WHAMO software is used in the analysis which uses the implicit finite difference scheme for solving the momentum and continuity equations at unsteady state case. Assiut city water supply network is used in the analysis. Flow of pipe network is studied due to; firstly, the sudden change in water demand at one or more junctions, secondly, the closing of some pipes of the network on the transient pressure and flow rates, and finally the failure in some network pipelines on intrusion or leakage due to transient pressure head fluctuations. The previous cases are studied in steady normal case, without any protection, and under different protection device(s) such as non-return valve and open surge tank. The results showed that rapidly change in demand increases the pressure head and flow rate fluctuations. Closing some pipelines increases pressure in a region and decreases it at another and also changes the direction of flow in the network. Also, failure of some pipelines can cause intrusion and leakage from outside the network to inside and inversely, which affects the values of minimum pressure heads more than the maximum ones

This research studies the effect of abnormal operation conditions on water hammer phenomenon in water supply pipe network in order to provide an acceptable level of protection against system failure due to pipes collapse or bursting. Water Hammer and Mass Oscillation WHAMO software is used in the analysis which uses the implicit finite difference scheme for solving the momentum and continuity equations at unsteady state case. Assiut city water supply network is used in the analysis. Flow of pipe network is studied due to; firstly, the sudden change in water demand at one or more junctions, secondly, the closing of some pipes of the network on the transient pressure and flow rates, and finally the failure in some network pipelines on intrusion or leakage due to transient pressure head fluctuations. The previous cases are studied in steady normal case, without any protection, and under different protection device(s) such as non-return valve and open surge tank. The results showed that rapidly change in demand increases the pressure head and flow rate fluctuations. Closing some pipelines increases pressure in a region and decreases it at another and also changes the direction of flow in the network. Also, failure of some pipelines can cause intrusion and leakage from outside the network to inside and inversely, which affects the values of minimum pressure heads more than the maximum ones

ABSTRACT The effect of using different protection devices on water hammer phenomenon to provide an acceptable level of protection against system failure due to pipe collapse or bursting is presented. Water Hammer and Mass Oscillation (WHAMO) software is used in the analysis which uses the implicit finite difference scheme for solving the momentum and continuity equations at unsteady state case. Assiut city water supply network is used. The network is supplied from two points at pump No. 36 and pump No. 37. Flow of pipe network is studied under steady normal case, without any protection case against water hammer phenomenon, and the model under different operation cases; with a transient protection device(s) such as non-return valve, open surge tank, air chamber and pressure relief valve (PRV). The results are performed for three scenarios; the first is the normal operation of pump 36 and failure of pump 37, the second is the normal operation of pump 37 and failure of pump 36, and finally failure of pumps 36 and 37 together. The results showed that using of open surge tank or air chamber with non-return valve protects the pipe network effectively from the harm of water hammer. Also, using PRV with non-return valve protects the pipe network from extreme pressures. Although using non-return valve only doesn’t have a great effect on the maximum pressure head than the normal case, it protects the network from the more low pressures than without protection one. All protection cases safeguard the pipe network from the extremes of water hammer, but increase the water hammer wave period. Finally, the sudden shut down of the pumps 36 and 37 together has the large effect on the pressure heads than the shut down of any of them only.