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SUMMARYA method is suggested to deal with the wave propagation problems in composite-laminated plates subjected to uncertainty in load and material property based on the interval analysis method and the hybrid numerical method (HNM). The uncertain parameters are treated as intervals, in which only their bounds of the uncertainty are needed. Using the first-order Taylor expansion, the transient responses can be approximated as a linear function of the uncertain parameters. In this function, the transient responses at the midpoints of the uncertain parameters can be obtained directly through the HNM. A sensitivity analysis technique is suggested to calculate the first derivative of the transient responses with respect to each uncertain parameter based on two cases that the parameter exists in load or material property. Applying the interval extension in interval mathematics, the lower and upper bounds of the transient responses caused by the uncertainty can be finally obtained. The present method is applied to a numerical example, in which the uncertainty of the load, elastic constants of the layer material and ply orientations are all investigated, and the results demonstrate the effectiveness of the present method.

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Although precast concrete structures have been widely used in building engineering, their application in moderate- and high-seismic zones is restricted because of poor lateral performance. This study proposed a fully assembled precast concrete frame with buckling-restrained braces (PCF-BRB) to simplify construction and enhance seismic performance. A nonlinear finite element model of the PCF-BRB was established using ETABS to investigate the feasibility of its use in seismic regions. The accuracy and rationality of the analysis model were verified by existing experimental data. Furthermore, the seismic performance, including plastic hinge development, internal force distribution, maximum inter-story drift, and energy dissipation, of the PCF-BRB was evaluated through static pushover analysis and dynamic time history analysis. The analysis results showed that the PCF-BRB has good seismic performance. Finally, this study provided a recommended seismic performance factor for design, namely the stiffness ratio of buckling-restrained braces (BRBs) to the frame (k, defined later) for the PCF-BRB structure. It is recommended that the stiffness ratio range of low-rise PCF-BRB structures should be 1.5 ≤ k ≤ 3.0, and that of high-rise PCF-BRB structures should be 3.0 ≤ k ≤ 4.0.

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