Analysis Of RC Structures Subject To Vibration By Using Ansys

Recent historic events have shown that buildings that are designed in compliance with conventional building codes are not necessarily able to resist blast effects. It was observed in the past events that progressive or disproportionate collapse generally occurred due to deficient blast performance of the structure, albeit in compliance with conventional design codes. In the past, safety of structures against blast effects was ensured, to a limited extent, through perimeter control; which minimizes damage by preventing the direct impact of the blast effects on the building. With the emergence of blast resistant structural design, methodologies to inhibit progressive collapse through the structural components performance can be developed, although there are no available adequate tools to simulate or predict progressive collapse behavior of concrete buildings with acceptable precision and reliability. This paper presents part of an effort to find an affordable solution to the problem. State of the art review of the blast analysis and progressive collapse analysis procedures will be presented. Preliminary analysis has been carried out to establish the vulnerability of a typical multistory reinforced concrete framed building in Riyadh when subjected to accidental or terrorist attack blast scenarios. In addition, the results of the blast vulnerability assessment will be used to develop mitigation approach to control or prevent progressive collapse of the building. For protective structures, reinforced concrete is commonly used. Concrete structures subjected to explosive loading in a combination of blast and fragments will have very different response than statically loaded structure. During the blast and the fragment impacts the structure will shake and vibrate, severe crushing of concrete occurs and a crater forms (spalling) in the front of the concrete; for large penetration, scabbing may occur at the backside of the wall, or even perforation, with a risk of injury for people inside the structure. This thesis is intended to increase the knowledge of reinforced concrete structures subjected to explosive loading, i.e. effects of blast and fragmentation. A further aim is to describe and use the non-linear finite element (FE) method for concrete penetration analyses. Particular attention is given to dynamic loading, where the concrete behavior differs compared to static loading. The compressive and tensile strengths increase due to the strain rate effects. Initial stiffness increases, and moreover the concrete strain capacity is increased in dynamic loading. Traditionally, for prediction of the depth of penetration and crater formation from fragments and projectiles, empirical relationships are used, which are discussed here together with the effects of the blast wave that is caused by the explosion. To learn more about the structural behavior of concrete subjected to severe loading, a powerful tool is to combine advanced non-linear FE analyses and experiments. A trustworthy model must be able to capture correct results from several experiments, including both the depth of penetration and the crater size. In this thesis, FE analyses of concrete penetration with steel projectiles have been performed and compared to existing experimental results.