The seismic performance of school buildings is crucially important in disaster response, as they are expected to serve as temporary shelters after major earthquakes. However, such buildings' seismic resistance is often inadequate, due to poor seismic design and/or ongoing processes of aging and deterioration. Therefore, a rapid and reliable methodology for holisti- Abstract. The assessment of the seismic performance of existing school buildings is especially important in seismic-disaster mitigation planning. Utilizing a support vector machine coupled with a fast messy genetic algorithm, this study developed two inference models, both using the same input variables: i.e., 18 building characteristics selected based on expert opinion. The first model was designed to judge whether a building needs to be retrofitted; and the second, to estimate the cost of retrofitting buildings to specific levels. The study proposes a life-cycle seismic risk framework that takes into account projections of the seismic risk a given building will confront over the course of its entire existence, and thus helps determine the economically optimal level of retrofitting. The results of a case study indicate that the higher upfront cost of retrofitting that is required to reach higher seismic performance levels could, depending on the level of predicted seismic risk, be offset by lower repair costs in the long run. It is hoped that this research will serve as a basis for further studies of the assessment of the life-cycle seismic risk of school buildings, with the wider aim of arriving at an economically optimal building-retrofit policy. OPTIMIZATION

Aiming at some stress-induced failure phenomena in surrounding rock that occur during the construction of super-long and deep-buried tunnels, a method for estimating the in situ stress in the tunnels based on multivariate information integration is proposed, which uses a small amount of in situ stress measurement, stereographic projection technology, and a numerical simulation method. Firstly, by conducting a macroscopic analysis of the regional geological structure, topography, and pre-excavated small tunnels (such as exploration of adits and pilot tunnels), the strength of the tectonic stress field and the orientation of the principal stresses in the tunnel sections are preliminarily determined. Secondly, the reliability of the in situ stress measurement data were analyzed using full-space stereographic projection and the plane stress projection method. Then, some representative measurement points that reflected the distribution characteristics of in situ stress in the project area, on the whole, were determined. Thirdly, the finite difference (FDM) and multiple regression analysis (MRA) methods were used to inverse the in situ stress field in the project area. The proposed method was applied to a super-long and deep-buried tunnel project in Qinling, and the in situ stress distribution characteristics of the tunnel sections at different mileages were obtained. The results show that both the calculated principal stress values and the azimuth angle of the maximum horizontal principal stress are in good agreement with the measured ones, indicating that the method used in this study is reasonable. Finally, the typical surrounding rock failure phenomena encountered during the excavation of the project were investigated, and targeted treatment measures were proposed. The research results can provide references for support design and disaster management of surrounding rock in deep-buried long tunnels.

The bonding state of the pile-soil interaction is complex. Traditional monitoring methods and tools have not been fully applied to monitor and evaluate it although it affects the lifecycle safety of the pile. In this study, a health monitoring method is proposed to evaluate the bonding state of the pile-soil contact area; it is a transient impact response method based on piezoelectric ceramic sensors to monitor the pile-soil bonding state. During the test, different damage degrees of the pile-soil bonding state were simulated by considering the working conditions of different soil densities and different crack depths as examples. A horizontal transient impact stress was applied to the pile top, and a piezoelectric ceramic sensor embedded in the pile detected the stress wave. As the stress wave response differs in different damage conditions, an energy index was established to quantitatively monitor the degree of damage.