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Existing structures can be retrofitted against earthquakes with tuned sloshing water dampers (TSWD). These dampers can be incorporated in the structure as displacement response reduction devices for avoiding failure of masonry panels while ensuring their structural function as diagonal struts. The proposal of retrofitting for an existing four story building with TSWDs has been examined through simulated experiments on a reduced scale model of the structure mounted with actual size TSWD. The effectiveness of the single frequency TSWD systems, optimally designed for response control of accurately assessed structures, against well-defined excitations, has been substantiated. Experiments have been conducted with multi-frequency TSWD systems for approximately assessed structures against broadband excitations. The multi-frequency sloshing water damper system exhibited a comparatively robust performance against broadband excitations for a reasonable range of structural frequencies. A retrofitting scheme for the structure has been proposed with multi-frequency TSWD systems.

Structural engineers usually make simple hand calculations to pre-design structures before performing further complex analysis. However, in the case of structures subjected to impact loads, the problem is quite difficult to cope with, due to the lack of knowledge about simplified methods of analysis that can reproduce with sufficient accuracy the structural behavior, in order to establish an adequate pre-dimensioning, prior to a computer calculation. In this paper, a new formulation is presented to solve the problem of large mass impact on any kind of structure in a simplified way. The method enables a force equivalent to the impact load to be obtained that enables analysis as a static load case.

The spatial-varying frequency of a vehicle-bridge interaction (VBI) system subjected to a moving mass is theoretically derived and numerically investigated through a three-dimensional VBI model, in which the effects of moving mass are introduced through the inertial force and centrifugal force in the equation of motion of the bridge. For a large vehicle-to-bridge mass ratio, it has been known that the frequency of a VBI system could change with respect to the location of a moving vehicle. As such, this study derives the analytical solution based on a moving mass-beam system to account for frequency variation and further builds the numerical model with detailed implementation for practical applications. The numerical results show the following findings: (1) The frequency of a VBI system is a function of velocity and location of a moving vehicle. (2) The reduction of spatial-varying frequency ratio for a particular mode decreases with respect to the mode of higher order. (3) The maximum reduction of spatial-varying frequency ratio of the first mode in a moving mass-beam system occurs in the location where the bridge has the maximum deflection as a result of local mode excitation. (4) For the VBI system with high suspension stiffness and large vehicle-to-bridge mass ratio, the absolute variation of spatial-varying frequency ratio of the first mode can be up to 30–40%.

The operator-splitting (OS) method for real-time substructure testing (RTST) provides explicit and unconditionally stable solutions for structures with softening type stiffness and damping has been widely used for precisely disclosing the seismic performance of structures with velocity-dependent specimens. However, the OS method for RTST provides only explicit target displacement and velocity but not an explicit target acceleration, so that it is essentially an implicit method for Dynamic real-time substructure testing (DRTST) with dynamic system specimens. For precisely disclosing the seismic performance of multiple-degree-of-freedom structures with dynamic system specimens, one improved OS method is proposed for DRTST in this paper. The methodology and stability of the proposed OS method are investigated, and the effectiveness of the proposed OS method is validated by numerical simulations and experimental tests. By using the predictor displacement, velocity, and acceleration approximations, the OS method is an explicit algorithm for DRTST. The stability analysis shows that the proposed OS method is conditionally stable for DRTST, and its stability limit decreases with the increase of the mass ratio and the stiffness ratio, while it increases first and then decreases with the increase of the damping ratio. The numerical and experimental results confirm the stability and accuracy of the OS method. The OS method for DRTST provides a practical and precise investigation strategy for structures with dynamic system specimens and may have broad application prospects in civil engineering.

The precision measurement of the W boson properties, such as its mass and width, constitutes an important consistency check of the Standard Model. This paper, in particular, describes methods to measure the W mass with improved precision at the Large Hadron Collider, exploiting the large number of Z bosons produced. The precision on the W boson mass achievable with an integrated luminosisty of 10 fb^-1 is discussed.