Optimum Location And Bracing System As Alternative To Shear Walls For Retrofitting Of RC Buildings Against Seismic Loading

The defective structures must be retrofitted to resist the effects of earthquakes due to the potential risks connected with reinforced concrete structures designed in many parts of the world in accordance with codes that are now proven to guarantee insufficient safety against seismic loads. Typically, shear walls or steel bracing are utilized to boost the seismic strength of framed structures. This paper discusses the possibility of using braces in two different conditions, the first one is in retrofitting already constructed structures that don’t have sufficient strength against seismic loading, and the second one is the possibility of using braces instead of shear walls in designing non constructed reinforced concrete structures for economical purposes. Different bracing systems in different locations compared with reinforced concrete shear walls in affecting the structural properties of the 10-story square building. Using bracing in the interior frames of buildings was also considered. The results show that different bracing systems have different responses for structural properties such as story displacement, base shear and fundamental time period. The results are significant for detecting the best bracing system to use instead of shear walls reflecting for the two mentioned scenarios as well as considering their locations on the building

SIMULTANEOUS FORCE AND DEFORMATION CONTROL OF CABLE ARCH STAYED BRIDGES

The tendency to build cable arch stayed bridges is increasing due to their aesthetic appearanceand efficient performance. Due to overloading or time passing, they may face deformation thusthey are required to be reshaped. For the same explanations the cables could undergo hightension and some others face slack, in order to keep the bridge safe in terms of stress failure,the redistribution of internal force of cables is essential. Pragmatically, the displacementrestoring and the force redistribution are simultaneously necessary, since both issues arisetogether. This paper deals with simultaneous control of nodal displacement and internal forceof cable theoretically by MATLAB Program and experimentally of a linear and a geometricallynonlinear model. The paper also shows that how the technique of adjustment response to controllinear and geometrically nonlinear structures. It was determined that the technique waspragmatic and effectual for linear structures. While it was not very accurate for geometricallynonlinear structures, since more than one iteration was required to get the target.HTTP://DX.DOI.ORG/10.30572/2018/KJE/10040

Simultaneous displacement and internal force prescription in shape control of pin-jointed assemblies

This paper presents a direct method for controlling nodal displacements, internal bar forces, and simultaneously both nodal displacements and internal bar forces, of a prestressable pin-jointed assembly under load. The method is aimed at static shape control of geometrically sensitive structures through length actuations in selected bars. The paper discusses identification of the most effective bars for actuation so that the desired shape can be obtained, without incurring violation in bar forces, through both a minimal number of actuators and minimum actuation in those actuators. The method can also be used for adjustment of bar forces to either reduce instances of high forces or increase low forces (e.g., in a cable nearing slack). Read More: http://arc.aiaa.org/doi/10.2514/1.J05481

Displacement and force control of complex element structures by Matrix Condensation

A direct and relatively simple method for controlling nodal displacements and/or internal bar forces has been developed for prestressable structural assemblies including complex elements ("macro-elements", e.g., the pantographic element), involving Matrix Condensation, in which structural matrices being built up from matrices of elementary elements. The method is aimed at static shape control of geometrically sensitive structures. The paper discusses identification of the most effective bars for actuation, without incurring violation in bar forces, and also with objective of minimal number of actuators or minimum actuation. The advantages of the method is that the changes for both force and displacement regimes are within a single formulation. The method can also be used for adjustment of bar forces to either reduce instances of high forces or increase low forces (e.g., in a cable nearing slack)