Quick Seismic Protection of Weak Masonry Infilling in Filled Framed Structures Using Flexible Joints

Abstract

This paper deals with research related to repair and strengthening of weak and brittle masonry infills in R.C. or steel frame structures. Masonry infills are commonly used in 20th century architectural heritage residential and office buildings. In case of earthquake damage to the weak and brittle masonry infills the commercial buildings go out of service and residents of residential buildings are prohibited from living in their homes although the main frame structure is not damaged. The new retrofitting method proposed in this paper may be either a preventive seismic improvement or a quick emergency intervention before seismic aftershocks: it is proposed to use a polymer PM to fill new horizontal and vertical joints between infilling masonry and frame or to fill cracks generated by the earthquake. The test results presented in the paper confirmed ability of polymer PM to fulfil requirements of quick repair material for seismic area.

Durability of PS-Polyurethane Dedicated for Composite Strengthening Applications in Masonry and Concrete Structures

“…One of the major cause of deaths in case of an earthquake are failures of buildings and other masonry structures due to their brittle behavior. It was proven that such failures can be successfully avoided or at least delayed in time with different technologies based on polyurethanes (PU) and their fibrous composites [2][3][4][5][6][7]. Polyurethane flexible joints (PUFJ) and fiber reinforced polyurethanes (FRPU) have been introduced in the last decade and investigated in laboratory and in-situ tests concerning their mechanical properties.…”

“…PUFJ and FRPU were tested as structural bonding systems, which transfer high loads and high deformations simultaneously. This ability was utilized in the repair of cracked masonry and concrete structures using PUFJ [2,[5][6][7]. They have been working in various environmental conditions and under the influence of chemical agents [7].…”

Deformable Polyurethane Joints and Fibre Grids for Resilient Seismic Performance of Reinforced Concrete Frames with Orthoblock Brick Infills

“…Brittle materials (e.g., clay bricks, concrete [1]) can be found in the majority of civil engineering buildings and especially in those that are made of masonry or reinforced concrete (RC). Connectors of brittle structural members may be: stiff joints (capable to carry high loads but unable to undergo large deformations) or sealants (capable to undertake high deformations but unable to carry high loads) [2].…”

“…Stress concentrations overcome strength of the substrates, generated by stiff adhesives [12,[16][17][18][19]. In seismic areas, high amount of ductility and deformation capacity of structures are required [1,5,20,21], thus other bonding solutions are sought, more compatible with masonry and concrete substrate [22][23][24][25]. The PFJ introduces greater tensile and shear resistance, deformability and ductility and thus greater bearing capacity (damage energy) in the bonded brittle structural elements, also in the post failure deformation zone-making the structure safer [1,15].…”

Flexible Adhesive in Composite-to-Brick Strengthening—Experimental and Numerical Study

“…In the last few years, the applications of flexible polyurethane adhesives FRPU/SRPU (Fiber/Steel Reinforced Polyurethanes) were tested on masonry substrates [18,19,20,21,22,23,24]. The effectiveness of composite strengthening, bonded on flexible adhesives to concrete substrates was also demonstrated [25,26].…”