Highly Dissipative Materials for Damage Protection against Earthquake-Induced Structural Pounding

Abstract

It is a common situation that seismic excitations may lead to collisions between adjacent civil engineering structures. This phenomenon, called earthquake-induced structural pounding, may result in serious damage or even the total collapse of the colliding structures. Filling the gap between two buildings erected close to one another by using visco-elastic materials can be considered to be one of the most effective methods to avoid seismic pounding. In this paper, a new polymer–metal composite material made of polyurethane and closed-cell aluminum foam is proposed as a pounding energy absorber for protection against earthquake hazards. The composite was created in two versions, with and without an adhesive interface. A series of experiments which reflect the conditions of seismic collision were performed: quasi-static compression, dynamic uniaxial compression and low-cycle dynamic compression with 10 loops of unloading at 10% strain. The composite material’s behavior was observed and compared with respect to uniform material specimens: polymer and metal foam. The experimental results showed that the maximum energy absorption efficiency in the case of the new material with the bonding layer was improved by 34% and 49% in quasi-static and dynamic conditions, respectively, in comparison to a sole polymer bumper. Furthermore, the newly proposed composites dissipated from 35% to 44% of the energy absorbed in the cyclic procedure, whereas the polymer specimen dissipated 25%. The capacity of the maintenance of the dissipative properties throughout the complete low-cycle loading was also satisfactory: it achieved an additional 100% to 300% of the energy dissipated in the first loading–unloading loop.

Specifications for Modelling of the Phenomenon of Compression of Closed-Cell Aluminium Foams with Neural Networks

“…The authors would like to kindly acknowledge Roman Gieleta for his help in the experimental part of the present article and publication [ 28 ].…”

“…We would also like to highlight civil engineering and architecture here, since these application fields are unjustly underestimated in the metal foam industry even though they have significant potential. Examples of the usage of closed and open cellular metals include: structural elements (e.g., wall slabs, staircase slabs, parking slabs) [ 17 , 21 , 22 ], interior and exterior architectural design [ 23 , 24 ], highway sound absorbers [ 5 , 25 ], architectural electromagnetic shielding [ 26 ], sound absorbers in metro tunnels [ 17 ], dividing wall slabs with sound insulation (e.g., for lecture halls) [ 27 ] and the novel concept of earthquake protection against building pounding [ 28 ].…”

Finite element modeling of plastic hinges based on ductility demand‐capacity method using nonlinear material for dynamic analysis

“…A plastic hinge does not allow for rotation under loads smaller than that which plasticizes the hinge, but under greater loads it transmits the boundary moment and allows for rotation, see Zhao et al 26 For supports made of concrete, taking into account the concept of plastic hinges, correct plastic analysis requires the use of a plastic‐degradable model of concrete. In this model, during element loading, the load‐bearing capacity limit is reached as a result of degradation of the material from the increase in external load, and consequently, the load‐bearing capacity is lost due to the increase in plastic deformation, see Lubliner et al, 21 Lasowicz et al, 27 Stręk et al, 28 and Oller et al 29 This is a very important element of the analysis, thanks to the location of the place where the support material degrades the fastest and to the greatest extent, it is possible to determine the place where plastic hinges are formed. This is due to the fact that where concrete loses its load‐bearing capacity, reinforcement (i.e., steel) starts to play a major role in transferring the loads.…”

A new ANN rheological model of a comply polymer in temperature spectrum

“…Comply polymers are materials widely used in civil engineering technology. Exemplary applications comprise: connections in structural elements [1], reinforcement of traditional building materials like bricks or timber [2], reinforcement of historic or heritage buildings or structures [3], bonding layers in protection composites against earthquake-induced pounding of buildings [4]. The given examples do not, of course, exhaust the field of application of comply polymers in the building industry and civil engineering; however, they show some characteristic conditions in which these materials can work.…”