An equivalent discrete model is developed for time domain dynamic analysis of uniform high-rise shear wall-frame buildings with fixed base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allow the consideration of intermediate modes of lateral deformation. The proposed model was validated by a building whose lateral resisting system consists of a combination of shear walls and braced frames. The results showed the effectiveness of TMDs to reduce the peak displacements, interstory drift ratio, and accelerations when the building is subjected to a seismic load. The root mean square accelerations due to along-wind loads also decrease if TMDs are attached to the building. KEYWORDScoupled two-beam model, earthquake engineering, passive control devices, tall buildings, tuned mass dampers, wind engineering | INTRODUCTIONThe lateral deformation of certain types of buildings can be modeled by shear beams and flexural beams. However, there are many buildings for which these two extreme modes of lateral deformation do not adequately represent their dynamic behavior. [1][2][3][4][5][6][7] Miranda, [8] Miranda and Reyes, [9] Miranda and Taghavi, [10] Reinoso and Miranda, [11] Miranda and Akkar, [12] and Cruz et al. [13] considered intermediate modes of lateral deformation in seismic response of buildings through a two-beam model that couples the bending and shear stiffnesses in parallel. Van Oosterhout [14] used the same coupled two-beam model to evaluate the wind-induced acceleration in tall buildings through an analysis in the frequency domain.Dym et al. [15] and Rahgozar et al. [16] considered intermediate modes of lateral deformation in buildings through a Timoshenko beam model that accounts for shear deformation and rotatory inertia by adding them to an Euler-Bernoulli beam. This model reflects a series coupling of the beam's bending and shear stiffnesses, although the effect of rotational inertia is not a significant factor in tall buildings. [15] The literature features several empirical formulas that allow the estimation of the lowest natural frequency of a tall building as a function of its height. [17][18][19][20][21] Dym and Williams [22] concluded that a coupled shear-flexural model in parallel seems the better model for estimating the frequencies of shear wall-frame buildings because it provides predictions that are consistent with the observed data. On the other hand, a Timoshenko beam model cannot exhibit the correct dependence between the frequencies and the height of the building because it reflects a series coupling of the beam's bending and shear stiffnesses. [22] This shows that a coupled shear-flexural model estimates better the frequencies of tall buildings than a Timoshenko beam model, particularly in shear wall-frame buildings and tube-and-core constructions with the parallel nature of the two-beam model in which transverse displacements du...

SummaryAn equivalent coupled‐two‐beam discrete model is developed for time‐domain dynamic analysis of high‐rise buildings with flexible base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allows the consideration of intermediate modes of lateral deformation. The equivalent model is applied to a shear wall–frame building located in the Valley of Mexico, where the effects of soil–structure interaction (SSI) are important. The effects of SSI and TMDs on the dynamic properties of the shear wall–frame building are shown considering four types of soil (hard rock, dense soil, stiff soil, and soft soil) and two passive damping systems: a single TMD on its top (1‐TMD) and five uniformly distributed TMDs (5‐TMD). The results showed a great effectiveness of the TMDs to reduce the lateral seismic response and along‐wind response of the shear wall–frame building for all types of soils. Generally speaking, the dynamic response increases as the flexibility of the foundation increases.

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A unified design model is proposed for various kinds of passive dynamic absorbers (PDAs) attached to buildings with different lateral resisting systems. A total of five different PDAs are considered in this study: (1) tuned mass damper (TMD), (2) circular tuned sloshing damper (C-TSD), (3) rectangular tuned sloshing damper (R-TSD), (4) two-way liquid damper (TWLD), and (5) pendulum tuned mass damper (PTMD). The unified model consists of a coupled shear-flexural (CSF) discrete model with equivalent tuned mass dampers (TMDs), which allows the consideration of intermediate modes of lateral deformation. By modifying the nondimensional lateral stiffness ratio, the CSF model can consider lateral deformations varying from those of a flexural cantilever beam to those of a shear cantilever beam. The unified model was applied to a 144-meter-tall building located in the Valley of Mexico, which was subjected to both seismic and along-wind loads. The building has similar fundamental periods of vibration and different nondimensional lateral stiffness ratios for both translational directions, which shows the importance of considering both bending and shear stiffness in the design of PDAs. The results show a great effectiveness of PDAs in controlling along-wind RMS accelerations of the building; on the contrary, PDAs were ineffective in controlling peak lateral displacements. For a single PDA attached at the rooftop level, the maximum possible value of the PDA mass efficiency index increases as the nondimensional lateral stiffness ratio decreases; therefore, there is an increase in the vibration control effectiveness of PDAs for lateral flexural-type deformations.

Los puentes peatonales actuales son estructuras cada vez más esbeltas y flexibles, lo que ocasiona que estos sean más propensos a las vibraciones verticales inducidas por personas. En México no existen normas de diseño para la revisión del estado límite de servicio de este tipo de estructuras, lo que ocasiona que muchos peatones dejen de utilizarlos para cruzar vialidades. En este artículo se estudian tres puentes peatonales existentes en México, los cuales son modelados mediante vigas continuas tipo Euler-Bernoulli sometidas a cargas verticales peatonales en movimiento. Se observa que estos puentes no cumplen con los límites de confort establecidos en las normas internacionales, por lo que se diseña un sistema de control de vibraciones verticales basado en amortiguadores de masa sintonizada (AMS) para cada uno de ellos.