Development of Retrofitting Solutions: Remedial Wall Ties for Masonry Enclosure Brick Walls

The external envelope walls of a significant percentage of the residential building stock in Southern European countries is commonly constituted by infill masonry walls. However, thousands of square meters of this masonry wall typology presents severe issues of cracking and instability, related to the incorrect and deficient support conditions of the outer brick panel of the double-leaf wall solution. In this work, an experimental campaign divided in two phases has been performed to evaluate the effectiveness of two different remedial wall ties retrofitting techniques (Solution A and Solution B) used for double leaf horizontally hollowed clay brick masonry façades. The first phase of the experimental campaign was performed on 120 isolated specimens of horizontally hollowed clay bricks, resorting to post- and pre-NP EN 771-1 brick exemplars (that is, new and pre-existent aged bricks, respectively), as well as on 4 square wallettes, with a side length of 1.20 m, considered as representative of a real scale scenario, for evaluating the two remedial wall ties retrofitting techniques. The second phase of the experimental campaign was performed to fully characterize the different failure types as well as the slipping phenomena observed in the first phase of the experimental campaign, focusing solely on the retrofitting technique Solution B and comprises 24 tests performed on isolated specimens, resourcing to new and pre-existent aged bricks as well. The results obtained by the use of these techniques revealed an average anchorage strength value ranging from 0.25 to 2.5 kN for each tested tie-bar. Solution B reveals an increase of double of the anchorage strength value in comparison to Solution A. In this sense, the global results revealed a suitable applicability of both retrofit studied solutions.

Out-of-Plane Shaking Table Tests on Seismic Response of RC Frame Infilled with a New Type of Shale Fired Heat-Insulation Blocks

Shale fired heat-insulation block, which is made of shale, fly ash, building rubbish, and waste paper, is a new type environment-friendly product. In order to study the mechanical properties of shale fired heat-insulation block walls, four full-scale walls were tested under El-Centro, Taft, and Ninghe earthquakes using shaking table equipment, in which the influence of the spacing of cast-in-place belt and the connection between the wall and the frame on the out-of-plane seismic performance of the wall was taken into account. The subject of this study is mainly about out-of-plane dynamic response of masonry walls in terms of frequency, displacement, and acceleration. It could be concluded that the cast-in-place belt and the rigid connection between wall and RC frame could effectively reduce the out-of-plane seismic response of the infill masonry wall. Finally, the recommendations for the use of this type of block in the structure are given.

Observed damage in public school buildings during the 2017 Mexico earthquakes

In September 2017, two major earthquakes struck south and central Mexico. These earthquakes produced widespread damage in public and private school infrastructure. In Mexico, all school buildings are classified as essential infrastructure and are expected to attain an immediate occupancy performance level after major earthquakes. However, there is a large variation in the quality of the design and construction practices of these buildings due to age of construction, material quality and availability, and great socioeconomic gaps around the country. In this article, an analysis of the observed damage in public school buildings is presented. The results are analyzed depending on the structural system, construction material, and year of construction. The results showed that damage intensity in seismically designed buildings was significantly lower than that observed in the pre-1985 structures. Load bearing and infill masonry walls were the most damaged structural elements.

Behaviour of Partially Infilled Frames using Finite Element

This paper presents an explicit behaviour of Reinforced Concrete frame by considering the masonry infill wall material fully and partially in the structure. A two storey 2D frames of six different cases and 10 storey 3D building of four different cases with fully and partially assignment of infill masonry walls. Analysis was performed in E-TABS software for all the 10 cases by generating synthetic earthquake matched time history with response spectrum. The study was carried out the effect of infill wall on the behaviour of column. The results were discussed and maximum storey displacements were taken in to consideration to study the behavior of the structure. The Storey displacements for the ten cases were taken in to account and revealed that higher displacements were observed in the cases with the partial infill and effect on column due to the partial or absence of infill wall adjacent to the column.