An-Najah Blogs :: aminhelo http://blogs.najah.edu/author/aminhelo An-Najah Blogs :: aminhelo en-us Thu, 23 Nov 2017 00:19:04 IST Thu, 23 Nov 2017 00:19:04 IST webmaster@najah.edu webmaster@najah.edu Dynamic Behavior of Reinforced Concrete Structures with Masonry Wallshttp://blogs.najah.edu/staff/aminhelo/article/Dynamic-Behavior-of-Reinforced-Concrete-Structures-with-Masonry-WallsPublished ArticlesThe inclusion of a soft storey in multistory concrete buildings is a feature gaining popularity in urban areas where the cost of land is exorbitant In earthquake prone zones this feature has been observed in post earthquake investigations Although engineers are prepared to accept the notion that a soft storey poses a weak link in Seismic Design yet the idea demands better understanding The following study illustrates the importance of the judicious distribution of shear walls The selected building is analyzed through nine numerical models which address the behavior of framed structures The parameters discussed include inter alias the fundamental period of vibration lateral displacements and bending moment It is noticed that an abrupt change in stiffness between the soft storey and the level above is responsible for increasing the strength demand on first storey columns Extending the elevator shafts throughout the soft storey is strongly recommended An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 22 2008 Pages: 077-092 The Effect of Shear Wall Distribution on the Dynamics of Reinforced Concrete Structureshttp://blogs.najah.edu/staff/aminhelo/article/The-Effect-of-Shear-Wall-Distribution-on-the-Dynamics-of-Reinforced-Concrete-StructuresPublished ArticlesThe inclusion of a soft storey in multistory concrete buildings is a feature gaining popularity in urban areas where land is of exorbitant cost In earthquake prone zones this feature has been observed in post earthquake investigations Although engineers are prepared to accept the notion that a soft storey poses a weak link in Seismic Design yet the idea demands better understanding The following study illustrates the importance of the judicious distribution of shear walls The selected building is analyzed through nine numerical models which address the behavior of framed structures The parameters discussed include inter alias the fundamental period of vibration lateral displacements axial and shear forces It is noticed that an abrupt change in stiffness between the soft storey and the level above is responsible for increasing the strength demand on first storey columns Extending the elevator shafts throughout the soft storey is strongly recommended 2008 SEISMIC ENGINEERING CONFERENCE: Commemorating the 1908 Messina and Reggio Calabria Earthquake AIP Conference Proceedings Volume 1020 pp 1747-1754 2008 A scrutiny of the Equivalent Static Lateral Load method of design for multistory masonry structureshttp://blogs.najah.edu/staff/aminhelo/article/A-scrutiny-of-the-Equivalent-Static-Lateral-Load-method-of-design-for-multistory-masonry-structuresPublished ArticlesBuilding structures with a soft storey are gaining widespread popularity in urban areas due to the scarcity of land and due to the pressing need for wide open spaces at the entrance level In earthquake prone zones dynamic analysis based on the Equivalent Static Lateral Load method is attractive to the novice and the design codes leave the choice of the analysis procedure up to the discretion of the designer The following is a comparison of the said method with the more elaborate Response Spectrum Method of analysis as they apply to a repertoire of different structural models The results clearly show that the former provides similar results of response in structures with gradual change in storey stiffness; while it is over conservative for a bare frame structure It is however less conservative for structures with a soft storeyEvaluation of the Stiffness Matrix of an Indeterminate Truss Using Minimization Techniqueshttp://blogs.najah.edu/staff/aminhelo/article/Evaluation-of-the-Stiffness-Matrix-of-an-Indeterminate-Truss-Using-Minimization-TechniquesPublished ArticlesFor an existing reinforced concrete or steel structure the evaluation of the stiffness matrix may be hampered by certain physical limitations such as material deterioration resulting from prolonged use an adverse or in a corrosive environment The following is a method that allows the determination of the member stiffness of an indeterminate truss through a minimization technique of a properly constructed Error Function Thus exact sectional and material properties do not have to be known a prioriA Study of a Flexible Submerged Cylindrical Tank Subject to Lateral Ground Excitationhttp://blogs.najah.edu/staff/aminhelo/article/A-Study-of-a-Flexible-Submerged-Cylindrical-Tank-Subject-to-Lateral-Ground-ExcitationPublished ArticlesIn a submerged rigid oil storage tank it is possible to evaluate the internal and external hydrodynamic forces separately Internally the forces are due to internal waves generated at the oil-water interface Externally they are due to radiated waves When such a tank is made of steel at it is usually the case the internal and external forces get coupled through the flexibility of the shell hence their solutions become inseparable The following is an analytical treatment for the case of a flexible tank it expands the solution of the rigid tank to include the shell flexibility effect The submerged tank is assumed to be subject to a harmonic lateral ground excitationMathematical Analysis of a Vibrating Rigid Water Tankhttp://blogs.najah.edu/staff/aminhelo/article/Mathematical-Analysis-of-a-Vibrating-Rigid-Water-TankPublished ArticlesThe hydrodynamic pressure distribution on the wall of a vibrating water tank is traditionally expressed as a summation of two components; an impulsive component and a convective one obtained by separating the potential function into two parts This requires solving Laplaces equation in two stages each with a separate set of boundary conditions The following is one step systematic solution to the problem in a frame moving with the tank It proves to be simple compact and could lead to the impulsive frequency independent and the convective frequency dependent components of pressure at the water tank wallA Detailed and Simplified Solution to Hydrodynamic Forces on a Submerged Tank Subject to Lateral Ground Excitationhttp://blogs.najah.edu/staff/aminhelo/article/A-Detailed-and-Simplified-Solution-to-Hydrodynamic-Forces-on-a-Submerged-Tank-Subject-to-Lateral-Ground-ExcitationPublished ArticlesThe domain where a submerged vertical cylindrical tank exists is divided into two regions Assuming irrational motion and an ideal fluid the Laplace s equations in both regions are solved by the method of separation of variables The integral equation resulting from matching the potentials at the interface is solved numerically by the Galerkin method It is shown that the mathematical labor is greatly reduced by dropping the surface effects and the results are in good agreement with those obtained by including surface effects albeit at higher values of excitation frequencies The case of protruding cylinder is presented to further illustrate the simplicity of the solutionDynamics of Internal Waves in Cylindrical Tankhttp://blogs.najah.edu/staff/aminhelo/article/Dynamics-of-Internal-Waves-in-Cylindrical-TankPublished ArticlesThe internal wave problem in a circular cylindrical tank is solved by the standard method of separation of variables Numerical results for the surface displacement at the interface as well as the pressure distribution at the wall are obtained J Wtrwy Port Coast and Oc Engrg Volume 111 Issue 2 pp 453-457 MarchApril 1985