One of the most reasonable ways to connect thin ultra-high performance concrete (UHPC) facades to building structures is bolted joints. To design the joints for the facades economically and safely, a clear investigation of the structural behavior is needed. In this study, the joint strength, failure modes and strain concentration phenomena of the bolted UHPC panels are investigated by direct tensile test. The main experimental variables are the geometric parameters, which are the width of the specimen, its thickness, and the distance from the center of the hole to the edge. Experimental results show that ductility of the joint depends on the failure mode. In addition, it is shown that the increase in the material cost of the panel, such as size and thickness, does not necessarily lead to an increase in the joint strength.
<p>Higher modular steel frames require lateral resisting systems against wind and earthquake loading. Modular steel frame systems have provided one of alternatives for rapid constructions such as school buildings, hospitals, emergency shelters, and dorms in a short time. For ease of construction in field and the allowance of tolerance of connection fabrication one intermediate diaphragm floor subsystems are introduced between steel modular systems and concrete core walls. The load transfer between these two systems is made possible by satisfactory performance of diaphragm action with reliable structural connections among subsystems. Commonly used anchorage connection details using embed steel plates welded to reinforcing bars were prepared to investigate structural performance of load transfer between the floor frames and concrete core walls. Tensile and shear resistance of wall connections are supposed to control the strength of the subsystems. Tensile and shear failures between embed plates and reinforcing bars are expected as one of governing failure modes between two subsystems. The experimental program of cyclic behavior was performed to investigate the structural performance of the proposed subsystems subjected to wind and moderate earthquake loading which can be applied to construction of the medium height residential modular buildings near future. To intend favorable failure mechanisms in the load transfer between the subsystems, failure sequences and ductile failure modes must be controlled. The proposed load transfer subsystem provides one of alternative for facile construction methods for mixed type of modular systems and stable structural performance.</p>
>> In this present study, a response modification factor for a lightweight steel panel-modular system which is not clarified in a current building code was proposed. As a component of the response modification factor, an over-strength factor and a ductility factor were drawn from the nonlinear static analysis curves of the systems modeled on the basis of the performance tests. The final response modification factor was then computed by modifying the previous response modification factor with a MDOF (Multi-Degree-Of-Freedom) base shear modification factor considering the MDOF dynamic behaviors. As a result of computation for the structures designed as a dual frame system, ranging from 2-story to 5-story, the value of 4 was estimated as a final response modification factor for a seismic design, considering the value of 5 as an upper limit of the number of stories.
>> A new formula is proposed for the fundamental period of high-rise residential concrete shear-wall (SW) buildings.This formula, developed on the basis of dynamics with the recorded fundamental period during the recent earthquakes, can consider the wall stiffness with respect to any direction. To verify the proposed formula, the fundamental period of 10 sample buildings, measured during construction, is compared with the predicted fundamental period. Furthermore, the empirical formulas presented in the building codes KBC 2009 and ASCE 7-10, are also compared with the proposed formula to show a rationality of the proposed formula. The comparison results show that the proposed formula not only can rationally consider the characteristics of each shear-wall, but that it also accurately predicts the fundamental period of the buildings.
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