土建专业外文翻译---二层预制混凝土结构物的抗震测试(编辑修改稿)

土建专业外文翻译---二层预制混凝土结构物的抗震测试(编辑修改稿)内容摘要：

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 shake table tests of a dual system. 8 DESCRIPTION OF TEST STRUCTURE The test structure used in this investigation is a twostory precast concrete building, representative of a lowrise parking structure located in the highest seismic zone of Mexico City. The prototype was constructed at onehalf scale. For the sake of simplicity, ramps required in a parking structure have not been considered in the selected prototype structure. Their use, requiring large openings in the floor system, would have required a very plex model of the floor system for both linear and nonlinear analysis of the structure. A detailed description of the dimensions, materials, design procedures, and construction of the test structure can be found A summary of this information is given below. The dimensions and some characteristics of the test structure are shown in Fig. 3. The longitudinal and transverse are shown in Fig3a. Also, the exterior (longitudinal) frame containing the wall (Column Lines 1 and 3) are termed the lateral frame (see Fig, 3b), and the internal (longitudinal) frame with the single tee (Column Line 2) are termed the central frame. Doable tees spanning in the longitudinal direction are supported by Lshaped precast beams in the transverse direction as shown in Fig3a. The structure uses precast frames and precast structural walls, the latter elements functioning as the main lateral load resisting system. Fig. 4 shows an early phase of the construction of the test structure. As can be seen, the windows39。 39。 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 9 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 factors, later discussed, that contributed to the overstrength of the structure. The longitudinal reinforcement in all the structural elements of the test structore was deformed bars from Grade 420 steel. Table 1 lists the concrete pressive cylinder strengths for different members of the prototype structure. Fig. 5 shows typical reinforcing details for precast beams spanning in the direction of the applied lateral load (see Fig. 3). Figs. 6 and 7 show reinforcing details for the columns, and for the structural wails and their foundation, respectively. It should be mentioned that the test structure was designed with the requirements for moderately ductile structures specified by the MCBC. According to these provisions, the test structure did not require special structural walls with boundary elements such as those specified in Chapter 21 of AC1 318 02. The precast twostory columns were connected to。