Non-linear Dynamic Analysis For Earthquake-induced Pounding Between Adjacent Structures

Earthquake is one of the most important factor of the current structural disaster. Asthe adjacent structures are usually in the different dynamic characteristics, it may causestructural pounding during severe ground motions easily. The pounding of structuresmay result in substantial damage or even total collapse of colliding structures. The mainreason for pounding can be summarized as follows, one is the dynamic characteristics ofadjacent structures are different, and the other is the separation distance betweenstructures could not meet the demand of minimum displacement for the relativemovement between adjacent buildings. In recent decades, the phenomenons ofearthquake-induced pounding have been repeatedly observed, and serious damage ofstructures was caused.The study demonstrates that there are quite a large number ofbuildings which have a potential risk of pounding in our country. Therefore, the studyfor the effect of pounding and the analysis for the mechanism of structural pounding areof great importance. Numerical simulation not only can be used to analysis the complexmechanism of structural pounding, but also can provide explaination for thephenomenon of pounding. Although it has been intensively studied by many scholarswith much simplified models, we need to build a more elaborative model to get moreaccurate results. This study takes earthquake-induced pounding between structures ofunequal heights as the research object. A sophisticated three-dimensional finite elementmodel is established, which takes the non-linear model of material behavior intoconsideration. Several aspects of analysis are carried out as follows.1. The commonly used research methods for structural pounding are sketched. Itmainly includes stereo-mechanical model method and contact model method. Theadvantages and disadvantages of four most basic contact model have been discussed.Then the contact criteria and contact algorithms of explicit dynamic finite elementmethod are introduced.2. In view of the pounding between the adjacent monolayer structures, asophisticated three-dimensional finite element model is established by using ANSYS/LS-DYNA. The impact of the collision on the structural response has beendiscussed.The impact of the level of ground motion, period ratio of structure and masseccentricity on the structural collision has been analysised.3. The adjacent multi-storey frame structures which are in different heights areselected as the research object. The model is used to research the impact of pounding onstructural dynamic response, such as interlaminar shear, floor displacement and so on.The impact of seismic gaps, the impact position, the level of ground motion, period ratioof structure and mass eccentricity on the structural collision has been discussed.