土建畢業(yè)設計外文翻譯---一個未完工的二層預制混凝土結構物的抗震測試-建筑結構-全文預覽
【正文】 CTILITY DEMAND IN DUAL SYSTEMS In order to develop a base for a later analysis of the observed seismic response of the test structure studied in this project a simple analytical model is used to evaluate the main features of ductility demands in dual systems. Fig 2 shows the results of a simple approach to analyze the lateral load response iii a dual system. The lateral load has been normalized in such a manner that the bination of maximum lateral resistance in both subsystern . walls and framesleads to a lateral resistance of the global system equal to unity b is also assumed that both subsystems have the same maximum lateral resistance. In the first case (Fig 2a), it is assumed that the wall and frame subsystems have global displacement ductility capacities equal to 4 and 2 respectively. In the second case (Fig. 2b), the frame subsystem response is assumed to be elastic, and the lateral stiffness of the wall subsystem is taken to be 4 times that of the frame subsystem. As shown in Fig 2, the lateral deformation patibility of the bined system is controlled by the lateral deformation capacity of the wall subsystem. In the first case Fig 2ak an elasticplastic envelope for the lateral global response of the dual system is assumed, and the corresponding displacement ductility (u) is equal to the second case (Fig. 2b) with an elastic behavior of the frame subsystem, this ductility is equal to 25. These simple examples illustrate that in the analyzed cases, due to the higher flexibility in the frame subsystems as pared to those of the wall subsystern, in a dual system, the ductility demands in the frame subsystem result in smaller ductility values than those of the wall subsystem. This analytical finding was verified in this study from the experimental studies conducted on the test structure. This verification is later discussed in the paper It is of interest to note that results of the type shown in Fig. 2 have been also found by Bertero39。 in the columns and walls are left in these elements for a later assemblage with the precast beams. The unfastened design base shear required by the Mexico City Building Code (MCBC, 1993)2 is , where WT is the total weight of the prototype structure, assuming a dead load of 5,15 KPa (108 psi) and a live load of KPa ( psi). The prototype structure was designed using procedures of elastic analyses and proportioning requirements of the MCBC, In these analyses, the gross moment of inertia of the members in the structure was considered and rigid offsets (distances from the joints to the face of the supports) were assumed for all beams in the structure except for beams in the central frame, which had substandard detailing as will be described latch. Results from these analyses indicated that the structural walls in the test structure would take about 65 percent of the design lateral loads. A review of the nominal lateral resistance of the structure using the MCBC procedures showed that this resisting force was about times the required code lateral resistance (0,2Wr), This is one of several factor
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