Research On Behaviour Of Infilled Freams Structures By Considering Of Interaction

The infilled walls were always considered as non structural components in the current design method, by ignoring the strength and rigidity of the infilled walls. However, the infilled walls and the freams word together under the lateral loads, such as wind loads and earthquake action. Under the influence of the infilled walls, the lateral stiffness, the ultimate bearing capacity and the failure form of the infilled freams are great different from the bare freams. Due to the complexity of the interaction between the infilled walls and freams, although lots of theory and experiment research about infilled frames have been done by many scholars all over the world, there is no consensus of opinion in analysis and design method by considering of interaction.In this paper the behaviour of single-storey one-bay infilled frames under monotonic lateral loads is studied and investigated analytically, on the basis of the previous research. To this purpose a precise finite-element micromodel is formulated and used, by considering contact interface conditions between the frame and the infill. This paper analyses lateral stiffness of the frames with infilled walls and investigates the influence of the infill panel opening percentage and the opening position in the reduction of the infilled frames stiffness. It is shown that: 1). The system's stiffness increases as the ratio of the width to the height of the infilled walls (l/h) increases. But the growth rate is gradually slow, which means that for values of the l/h ratio greater than 1.8 the system's stiffness tends to be independent of the l/h ratio.2). The system's stiffness decreases as the ratio of inertia moment of the beam to the columns (I2/I1) increases. 3). The increase in the system's stiffness is almost proportional to the increase of the infill's relative stiffness. 4). Considering the effect of the opening position, the stiffness of the structure can made different values in the opposite direction along the same line. We should consider this impact in the structure design.This article also does a research on seismic damage and elastic finite element analysis of a bottom weak layer structure in Wenchuan Earchquake. And suggestions in structure analysis and design, designers should consider the stiffness effect of infilled walls to avoid weak layer.