Shaking table tests of one and two story masonry building models seismically augmented with plastic waste reinforced cementitious composite

The unreinforced masonry structures have proved inefficient during earthquake events due to lower flexural/tensile strength, resulting in large loss of lives and properties. Although different strengthening methods have been investigated to date, those methods were found to difficult to implement in practice. Consequently, the present study proposes a mortar strengthening technique using waste plastic (polyethylene terephthalate, i.e., PET) fibre to enhance the seismic response of masonry structures. The use of waste plastics would also reduce the environmental problems arising due to the disposal of waste plastic in open landfills and marine ecosystems to a large extent. Waste plastic bottles were cut into fibres, which were then used to reinforce the mortar. In the current study, both one story and two story masonry models (scaling factor 1:3) were built using fly ash and clay bricks. Control (unreinforced) mortar was used for the unreinforced models and PET fibre-reinforced mortar was used in case of the reinforced models. The same mortar composition was used for joints (bed and head) and plastering. The one story models were subjected to the bi-directional seismic force generated by a bi-directional shaking table, and the two story models were subjected to the uni-directional seismic force generated by a uni-directional shaking table. Subsequently, a thorough investigation was carried out, and the results obtained were compared with those of unreinforced models. Moreover, various parameters related to seismic conditions, such as ultimate peak ground acceleration (PGA), crack propagation, energy flux ratio, arias intensity, failure pattern, damage grade, acceleration amplification factor, etc., were compared. It was found that there was a notable increase in the seismic safety of the strengthened models. The PGA causing the 1st crack strength was improved up to 46.2 % for one-story models and up to 137.1 % for two-story models. Likewise, the increase in the PGA causing the ultimate crack was up to 46.2 % and up to 117.1 % for one-story and two-story models, respectively. Furthermore, the reinforced models exhibited ductile and gradual failure. By and large, the mortar reinforcing method using waste PET fibres proved easy to implement, efficient, inexpensive (increase in cost up to 4 %), and sustainable.