Assessment Of The Effect Of Size Of Diaphragm Discontinuity (opening) On The Rigidity Of Diaphragm And Distribution Of Lateral Load To The Lateral Load Resisting Element

Earthquake - resistant structures are provided with lateral and vertical seismic force –rnresisting systems capable of transmitting inertial forces from the location of massesrnthroughout the structure to the foundations. Floor and roof diaphragms play a key role inrndistributing earthquake-induced loads to the lateral load resisting systems. Continuity andrnregular transitions are essential requirements to achieve adequate load paths. Floorrndiaphragm that has a large opening is likely to be inefficient in distributing seismic loads tornthe vertical elements.rnDesign codes like UBC-97 specify that diaphragms having cut out or open areas greater thanrn50 percent of the gross enclosed area of the diaphragm are affected by diaphragmrndiscontinuity[11]. However, there are different cases where this provision can bernunsuccessful. In order to investigate the effect of diaphragm discontinuity on the response ofrna structure, different parametric studies have been carried out. In the parametric studies,rnstory height, shear wall width, number of stories, number of bays, shape of diaphragmrnopening, diaphragm opening size, span length and opening location in stories are taken asrnparameters.rnThe study proceeded by assessing the effect of diaphragm discontinuity/opening on responsernof a structure like diaphragm rigidity, story drift, distribution of lateral load to lateral forcernresisting element and natural vibration period for each parametric study listed above. Thernstudy has shown that the rigidity of a slab does not only depend on the opening size, butrnrather depend on the stiffness of vertical elements, number of stories, aspect ratio of the slabrndimension and shape of diaphragm opening.rnMaster’s Thesis Effect of Diaphragm DiscontinuityrnStructural Engineering iv AAUrnThe investigation has shown that the code provision relating diaphragm rigidity to openingrnsize is not always satisfied.rnKey words: diaphragm discontinuity, opening, diaphragm rigidity, actual diaphragmrnstiffness, rigid diaphragm, flexible diaphragm, stiffness, story drift, lateral force distribution,rnperiod

Get Full Work

Report copyright infringement or plagiarism