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.

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.

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.

In geotechnical investigation, determination oftheseismic bearing capacity of foundation soil constitutes an important task. The bearing capacity of soil under static loading has been extensively studied since the early work of Prandtl (1921).Design of foundation in seismic areas needs special considerations compared to the static case. The inadequate performance of structure during recent earthquake has motivated researches to revise existing methods and to develop new method for seismic resistant design. For foundation of structure built in seismic areas the demands to sustain load and deformation during earthquake will probably be the severe in their design life. Due to seismic loading foundation may experience decreases in bearing capacity and increases in settlement. Two source of loading must be taken into consideration inertial loading caused by lateral forces imposed on the superstructure, kinematic loading caused by the ground movement developed during earthquake.

In geotechnical investigation, determination of the bearing capacity of foundation soil constitutes is an important task. Most of the previous studies investigated the stability of such foundation system using classical bearing theory. The classical bearing theory was developed depending on the theory of plasticity with the assumption that the soil behaves as a rigid-plastic material. The bearing capacity theories require making a guess on the shape and geometry of the most critical failure surface (mechanism of failure) a priori. Most theories assumed the geometry of the failing soil mass is symmetrical with respect to the center of the footing, while, Krey suggested that the geometry of the failing mass is unsymmetrical. Numerical methods do not require an initial assumption the geometry of the failure mode. In the present work, a numerical study assisted by a computer program is carried out using (Krey’s method) to investigate the center of the slip circle gives the minimum bearing capacity of the footing. Also, PLAXIS 2D used for analysis of some cases of studies by Krey’s method. Krey it's of the present study is compared with the classical theories of the ultimate bearing capacity. The predicted values of ultimate bearing capacity of soil of this study are less than those of others theories of ultimate bearing capacity. In order to facilitate the calculation of bearing capacity the proposed equations are used. It is a function of (footing width, (B), ratio of footing depth to its width, (Rf) , angle of internal friction of soil, (

Time history analysis was performed to study the effect of selected parameters in the behaviour of reinforced concrete frames under earthquake loads. The RC frames were designed for gravity-loads only as typically found in most seismic prone countries before the introduction of adequate seismic design code provisions. The parameters considered in this study were the number and span of bays, the number of stories, and the presence of infill wall (full infilled frame and infilled frame with open ground stories). It was observed that the presence of infill wall may affect the seismic behaviour of frame structure to large extent, and the infill wall increases the strength and stiffness of the structure. Also it was observed that infilled frames are preferred in seismic regions than the open ground story ones, because the story drift of first story in open ground story frames is very large than the upper stories, this may probably cause the collapse of structure.