Recent analytic, experimental, and practical studies are developing energy dissipation devices combined with amplifying mechanisms (AM) to enhance structural behavior. This research presents the theoretical and experimental development of the eccentric lever-arm system (ELAS), a new system generically called amplified added damping (AAD), which is a combination of an AM with one or more dampers capable of supporting large deformations. The proposed AM device is a variant of the well-known lever-arm system. This work is divided in four parts: (1) kinematics of the ELAS and definition of an equivalent AAD; (2) parametric analysis of a linear single-story structure with ELAS; (3) numerical analysis of a multi-degreeof-freedom structure with frictional damping with and without AM; and (4) pseudo-dynamic tests of a full scale asymmetric one story steel structure with and without frictional AAD. Parametric analyses demonstrate that using high-amplification ratios and low supplemental damping could be a good practice . On the other hand, similar to systems without AMs, dissipation efficiency increases conformably with the stiffness of the secondary structure. As expected, it was observed that deformation was highly concentrated in the flexible edge of the asymmetric test model without damper. Conversely, the structure with frictional AAD clearly showed uniform plane deformation. The implemented AM, which has a large amplifying ratio of˛ 11, performed with close accordance with numerical simulations and a high mechanical efficiency . 95%/ using a frictional damper with a very low force capacity.[1, 2]; and (ii)connecting the beam of the building and the damper though an auxiliary V-shaped structure ('chevron'), where the damper works horizontally. These configurations are shown in Figure 1 (a and b), where they are identified as diagonal and chevron systems, respectively.Both configurations are generally appropriate for flexible buildings. However, stiff structures such as buildings with reinforced-concrete shear walls obstruct the implementation of energy dissipation systems because inter-story drifts generated under seismic excitations can not produce enough deformation (and energy dissipation force) in the dampers. To overcome this problem, various amplifying mechanisms (AM) have been proposed [3,4], including the Toggle Brace Damper (TBD) [1, 5-7], scissor-jack damper [8], lever-arm systems (LASs) such as the DREAMY system of Taisei Corporation [9, 10], hydraulic amplification devices [11], seesaw-damper system [12][13][14], and amplification systems based on pinions with different diameters [15]. Figure 1 schematically shows some of these systems along with the traditional chevron and diagonal systems.It is important to note that the efficiency of energy dissipation devices depends on the stiffness of the elements designed to transmit deformation (inter-story drift) from the main structure to the energy dissipation devices (henceforth, named secondary structure or secondary system). Because both secondary structure ...

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This paper presents the numerical and experimental evaluation of a vertical‐rocking isolation (VRI). This evaluation is done by 1‐D shaking table tests performed on a full‐scale legged storage tank of 3000‐liters capacity and its representation through a simple yet representative rigid lumped‐mass model approach. The isolation system setup consisted of four ISO3D‐2G devices, each one placed on each leg of the tank, which uses high‐damping natural rubber to generate the restoring and dissipative forces. The ISO3D‐2G device is vertically flexible and laterally rigid, enabling the isolation mechanism of the rocking motion of the tank. The experiments were carried out using three white noise for the system identification and 17 ground motions inputs for the system validation. The measured variables included the lateral acceleration and displacement of the tank, and the vertical and rotational behavior of the isolation interface. The identification results showed a vertical‐rotational coupled fundamental mode that is highly dependent on the amplitude of deformation, with a period varying from 0.5 to more than 1 s, depending on the intensity of the motion. The maximum displacement of the tank at the top remained below 13 cm with total accelerations of nearly 0.3 g, both for motions with Peak Ground Acceleration (PGA) values ranging from 0.3 to 0.8 g. The mean maximum values were predicted with the simplified model with errors of less than 10% and 21% for displacements and accelerations, respectively. Finally, the results show that the behavior of vertical‐rocking isolated structures can be predicted by simplified models with reasonable errors and that the development of simple design guidelines and equations for VRI systems is possible.

Nowadays, freight transport is crucial in the functioning of cities worldwide. To dig further into the understanding of urban freight transport movements, in this research, we conducted a case study in which we estimated an origin-destination matrix for the trucks traveling on Autopista Central, one of Santiago de Chile’s most important urban highways. To do so, we used full real-world vehicle-by-vehicle information of freight vehicles’ movements along the highway. This data was collected from several toll collection gates equipped with free-flow and automatic vehicle identification technology. However, this data did not include any vehicle information before or after using the highway. To estimate the origins and destinations of these trips, we proposed a multisource methodology that used GPS information provided by SimpliRoute, a Chilean routing company. Nevertheless, this GPS data involved only a small subset of trucks that used the highway. In order to reduce the bias, we built a decision tree model for estimating the trips’ origin, whose input data was complemented by other public databases. Furthermore, we computed trip destinations using proportionality factors obtained from SimpliRoute data. Our results showed that most of the estimated origins belonged to outskirt municipalities, while the estimated destinations were mainly located in the downtown area. Our findings might help improve freight transport comprehension in the city, enabling the implementation of focused transport policies and investments to help mitigate negative externalities, such as congestion and pollution.

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