Tests on a Half-Scale Two-Story Seismic-Resisting Precast Concrete BuildingThis paper describes experimental studies on the seismic behavior and design of precast concrete buildings. A half-scale two-story precast concrete building incorporating a dual system and representing a parking structure in Mexico City was investigated. The structure was tested up to failure in a laboratory under simulated seismic loading. In some of the beam-to-column joints, the bottom longitudinal bars of the beam were purposely undeveloped due to dimensional constraints.Emphasis is given in the study on the evaluation of the observed global behavior of the test structure. This behavior showed that the walls of the test structure controlled the force path mechanism and significantly reduced the lateral deformation demands in the precast frames. Seismic design criteria and code implications for precast concrete structures resulting from this research are discussed. The end result of this research is that a better understanding of the structural behavior of this type of building has been gained results of simulated seismic load tests of a two story precast concrete building constructed with precast concrete elements that are used in Mexico are described herein. The structural system chosen in the test structure is the so called dual type, defined as the combination of structural walls and beam-to-column frames. Connections between precast beams and columns in the test structure are of the window type. This type of construction is typically used in low- and medium rise buildings in which columns are connected with windows at each story level. These windows contain the top and bottom reinforcement. Fig. 1 shows this type of construction for a commercial building in Mexico City. In most precast concrete frames such as those shown in Fig, 1, longitudinal beam bottom bars are not fully developed due to constraints imposed by the dimensions of file columns in beam-to-column joints. In an effort to overcome this deficiency, and as described later, some practicing engineers in Mexico design these joints by providing hoops around the hooks of that reinforcement in order to achieve its required continuity. However, this practice is not covered in the ACI Building Code (ACI318-02), nor in the Mexico City Building Code (MCBC, 1993). Part of this research was done to address this issue. The objectives of this research were Io evaluate the observed behavior of a precast concrete structures in the laboratory and to propose the use of precast structural elements or precast structures with both an acceptable level of expected seismic performance and appealing features from the viewpoint of construction Emphasis is given in this paper on the global behavior of the test structure. In the second part of this research which gill be presented in a companion paper, the observed behavior of connections between precast elements in the test structure, as well as the behavior of the precast floor system will be discussed in detail. Structural and non structural damages observed in buildings during past earthquakes throughout the world have shown the importance of controlling lateral displacement in structures to reduce building damage during earth- quakes. It is also relevant to mention that there are several cases of structures in moderate earthquakes in which the observed damage in non-structural elements in buildings was considerable even though the structural elements showed little or no damage. This behavior is also related Io excessive lateral displacement demands in the structure. To minimize seismic damage during earthquakes, the above discussion suggests the convenience of using a structural system capable of controlling lateral displacements in structures. A solution of this type is the so-called dual system. Studies by Paulay and Priestley4 on the seismic response of dual systems have shown that the presence of walls reduce the dynamic moment demands in structural elements in the frame subsystem. Also in conjunction with shake table tests conducted on a cast-in-place reinforced concrete dual system. Bertero5 has shown the potential of the dual system, in achieving excellent seismic behavior n this investigation, the dual system is applied to the case of precast concrete structures.DUCTILITY DEMAND IN DUAL SYSTEMSIn 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 combination of maximum lateral resistance in both subsystern i.e. walls and frames-leads to a lateral resistance of the global system equal to unity b is also assumed that both subsystems have the same maximum lateral resistan