Force transfer of the floor slab in a post-tensioned concrete 3D frame under two-directional lateral loads

[[abstract]]預力預鑄梁柱結構系統，使用無握裹預力鋼腱貫穿梁而連結柱，在地震過後利用預力鋼腱的預力作用，使構架回到原來的位置(Self-centering)，並可以降低地震後結構的殘餘變位。但是應用於實際結構時，剛性樓板勢必降低梁柱界面開口。因此，有必要針對樓板傳力機制進行研究。 本文為探討預力預鑄混凝土立體構架在雙向載重下之樓板傳力機制。建造一組單跨單層含樓板梁柱之立體構架，包含4根柱、4根梁以及2塊裝組合樓板。4根柱及2根梁分為兩組平面構架，即重力構架和預力構架。為了模擬真實地震力作用，力量加載由重力構架作雙向加載，經由2塊裝樓板和2根橫向梁，將地震力傳遞至預力構架。樓版及橫向梁皆施加預力，具有自回位之功能，同時不會影響預力構架梁柱接頭界面之開啟。 主要研究參數為兩塊裝樓板及橫向梁的預力變化對其傳力行為研究，並探討立體構架在雙向載重下之耐震行為。實驗結果顯示此結構系統在雙向載重下都能維持彈性關係只有微細裂縫，同時結構具有自回位的功能。[[abstract]]The precast and prestressed concrete structural systems utilize unbonded post-tensioned to connect beams and columns together The structure may return to its original position without residual deformations due to the prestress under earthquake loads (self-centering function) However floor slabs designed as a rigid diaphragm may reduce the gap-opening in the beam-column interface in practice Therefore it is necessary to investigate the force transfer of the slabs in the precast and prestressed concrete structural system This research aims to invertigate the force transfer of the floor slabs in the precast and prestressed concrete structure under bi-axial loads For this purpose a 3D one story sub-structure was constructed including four columns four beams and two slabs to form a gravity frame a post-tensioned frame and slabs in between In order to simulate the path of force transfer of inertial load during an earthquake the lateral loads was applied at the column of the gravity frame and then transmitted to the post-tensioned frame through the floor slabs and transverse beams where prestress was also applied to have self-centering function without interfering the gap-opening in the beam-column interface The primary invertigating parameters are the prestress level in the slabs and transverse beams Test results showed that the sub-structural remained elastic all the time without major damage restored its function after eachtest and returned to its original position without residual deformation