Precast construction elements are described suitable for use in high seismic areas. The precast construction elements can be precast, pre-topped double tees. The precast construction elements incorporate a passive energy dissipation device in a flange. The energy dissipation device provides a ductile connection having a deformation capacity of larger than 0.6″. Adjacent elements are connected to one another at joints that include the passive energy dissipation device. Passive energy dissipation devices can be passive hysteretic dampeners, such as U-shaped flexural plates. Passive energy dissipation devices can be bar dissipaters (e.g., grooved dissipaters). Also described are passive hysteretic dampers that include U-shaped flexural plates held in conjunction with a reinforcement element that defines a circle around which the flexural plate can bend.

A grid framework structure configured to support one or more load handling devices thereupon includes i) a grid structure including a plurality of grid cells; and ii) a load bearing framework, wherein the grid structure is suspended from the load bearing framework by three or more tension elements connected to a respective number of suspension points on the grid structure, each of the three or more tension elements having a length configured to suspend the grid structure in a substantially horizontal plane.

A tuned liquid damper, including a first outer housing having two ends, the first end being open to the atmosphere and the second end being connected by a conduit to a gas-filled second outer housing. The conduit may be adapted to allow gas flow between the second end and the second outer housing. The tuned liquid damper may also include first and second membranes, each attached to the inside of the first outer housing, and a sealed compartment within the first outer housing defined by the first and second membranes. The sealed compartment may be at least partially filled with a liquid, which prevents gas flow through the first outer housing from the first end to the second end.

The invention relates to an assembly method for a vibration damper of a tower of a wind power plant, in which the vibration damper is switched into a transport state from a state of use. The vibration damper is connected to a structural component of the tower such that a damper mass of the vibration damper can be set in motion, during which movement the distance between the damper mass and a central axis of the tower varies. The vibration damper is switched into the transport state by tilting the vibration damper compared to the state of use. The invention also relates to an associated assembly system.

The invention provides an adjustable stiffness assembly for use in conjunction with a fixed stiffness element to elastically connect a structure to a mass. The assembly includes a structure mount, a mass mount, and a rotatable stiffness element. The rotatable stiffness element rotatably engages with the structure mount and the mass mount, and has a minimum stiffness value with respect to forces in a direction a maximum stiffness value with respect to forces in another direction The fixed stiffness element and the adjustable stiffness assembly together provide a complete stiffness assembly having a total stiffness value with respect to force in the global direction for elastically connecting the mass and the structure. The first rotatable stiffness element is rotatable relative to the structure mount and the first mass mount to vary the total stiffness value of the complete stiffness assembly with respect to force in the global direction.

A new passive control building arrangement is provided for improving the seismic response of structures. The proposed control arrangement was incorporated to a 1/20 scale model of a steel structure. The SAP2000 software program was used to develop an analytical model of the constructed scale model. After using a series of experimental data to calibrate the analytical model, valuable information of the dynamic properties of the arrangement was obtained. Different configurations with distinct parameters of the control arrangement were analyzed in the program to evaluate the variables that affect the dynamic properties of the model. It was determined that the geometric configuration of the arrangement and the spring stiffness value of a spring used in the arrangement affect considerably the dynamic properties. Simulated earthquake tests were performed in two proposed alternatives of the control arrangement to evaluate their effectiveness in improving the seismic response of the scale model. It was observed that the control arrangement can effectively reduce the accelerations and base reactions of the model.

A sliding seismic isolator includes a first plate attached to a building support, and an elongate element extending from the first plate. The seismic isolator also includes a second plate and a low-friction layer positioned between the first and second plates, the low-friction layer allowing the first and second plates to move freely relative to one another along a horizontal plane. The seismic isolator also includes a lower support member attached to the second plate, with a biasing arrangement, such as at least one spring member or at least one engineered elastomeric element, which can include one or more silicon inserts, positioned within the lower support member. The elongate element extends from the first plate at least partially into the lower support member and movement of the elongate element is influenced or controlled by the biasing arrangement.

An active inertial damper system (100) and method for damping vibrations (V1,V2) in a structure (11). An inertial mass (2) is supported by a support frame (1) via spring means (3) to form a mass-spring system (2,3) having a resonance frequency (fn). A controller (6) is configured to control a force actuator (4) to adapt the driving force (Fd) as a function of measured vibrations (V1,V2). The controller (6) comprises a filter (H) determining a magnitude (M) of the driving force (Fd) as a function of frequency (f) for the measured vibrations (V1,V2) in the structure (11). The filter (H) is configured to provide an anti-resonance dip in the magnitude (M) of the driving force (Fd) at the resonance frequency (fn) of the mass-spring system (2,3) to suppress resonant behaviour of the mass-spring system (2,3) itself.

Example embodiments provide mechanical dampers. The mechanical dampers may be applied to dissipate energy in a structure that arises for example from a dynamic load such as seismic activity, vehicle impact, vibration of the structure, wind forces, an explosion, etc. The damper comprises a pair of clamping plates. A shear plate is held between the clamping plates. The shear plate is movable in transverse directions relative to the clamping plates. The damper also comprises a conical wedge coupled between one of the clamping plates and the shear plate. The conical wedge comprises a female conical element and a male conical element that projects into a conical indentation of the female conical element.

Described and shown are passive variable stiffness devices, which are of compact design and configured to produce a restoring force that varies optimally with the isolator displacement when subjected to vibration-inducing loading.