Development And Study On The Seismic Behavior Of Novel Joint In Pre-fabricated Modular Steel Building

Pre-fabricated Modular construction is a new style of construction in which the modular units are pre-fabricated in the factories,transported to the construction site and erected to form an assembled building.Pre-fabricated modular construction is different from traditional steel construction in terms of detailing of connections and construction methods.Because of faster construction it is highly adapted in mid-rise and high-rise construction.As the height of building increases the effects of lateral loads on the buildings become more severe.Connection in Pre-fabricated modular steel building system is the main part in load transfer,structure's stability and failure mechanism of the Modular Building.In this thesis,a new type of fully bolted connection having four parts including,upper part for upper modules,lower part for lower modules and gusset plate in between two parts for horizontal connection,and long bolts for horizontal connection is proposed.The ultimate structural behavior of the proposed connection was analyzed by using finite element modeling software ABAQUS/CAE,under Nonlinear static and Quasi-static loadings analysis to study the lateral load carrying capacity,moment-rotation curve,stiffness and seismic capacity of connection.The detailed connection was simplified by using the non-linear spring interaction in beam element model in ABAQUS to reduce computation time and use the connection as spring element.The structural behavior of the connection with gap between the adjacent modules was studied and the appropriate construction tolerance or gap was proposed.The structural behavior of the frames and 3-Dimensional Modular blocks using novel connection was also studied.The detailed models of frames and 3D module units were simplified using spring elements in ABAQUS.Then Dynamic analysis was performed on 5-storey and 12 module units full scale simplified building under real earthquake accelerogram to study the behavior,interstorey drift of modular building under real earthquake waves along both lateral directions.The Buckling analysis on the 3D simplified modular building was performed to get the buckled modes and effective length.The results revealed that because of the deformation caused by the lateral loads the gap is generated between the upper and lower part of connection which results in bearing failure of floor beam on tension side.As connecting parts are bolted together,the novel connection shows good ductile behavior.In 3-dimensional modules the bolts of floor beam on compression side are at higher stress level and fail in shear.The parametric study showed that length of the tenon plays an important role in the ultimate load capacity,moment capacity and stiffness of the connection,with increase of length load carrying capacity very obviously.The simplification of joint using rotational stiffness of connection showed accurate failure behavior of detailed model which would be assisting engineers in using connection as spring element for design purpose.The Dynamic analyses showed inter storey-drift was within code limits.Then,FEA is justified by analyzing connection in the reference.With these evidences the veracity of the FEA on study of nonlinear behavior novel connection was confirmed.