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Masonry often requires strengthening to withstand against extreme actions such as earthquakes, cyclones and flooding. Recently, new methods have been developed to strengthen masonry, such as fabric reinforced cementitious matrixes and fibre reinforced polymers. However, other strengthening systems such as welded wire meshing (WWM), reticulatus and plastering with cementitious matrixes/mortar (CP) have been also practiced to reinforce masonry, conversely no systematic design guidelines are available for these methods. In this study, an attempt has been made to establish rational design approaches to predict the shear resistance of WWM, reticulatus and CP methods. Three sets of experimental database have been developed for design verification. The effectiveness of these strengthening methods was appraised by comparing their structural performances. The available formulations to predict the shear resistance of unreinforced masonry (URM) and CP strengthened masonry were assessed against the established database, and suitable modifications were proposed to effectively account the contribution of cementitious matrix. A unified approach to estimate the shear strength was proposed based on the contribution of URM, CP and reinforcements. The design approach is shown to conservatively predict the shear strength of strengthened masonry. [ABSTRACT FROM AUTHOR]

In past decades, multistory housing buildings have been constructed in high-seismic-risk regions in Latin America using thin reinforced concrete (RC) walls as the primary earthquake-resistant structural system. Typically, these thin walls are built using a light amount of brittle welded wire mesh placed in a single curtain for longitudinal and transverse reinforcement. This type of construction system is convenient due to the higher speed of construction compared to construction with thicker walls and conventional reinforcement. However, the seismic design of thin walls in buildings is based mainly on limited experimental research, mainly on squat-thin RC walls. A limitation of thin RC walls is that a cold-drawn mesh has low ductility and low energy deformation capacity. Furthermore, thin walls that are subjected to earthquake loading could fail due to out-of-plane instability. A database of RC thin walls tested under compression-tension cycles or cyclic lateral loading by several authors is used in this study to review the mechanics of lateral instability of thin RC walls. This study's results are used to understand better the potential seismic behavior of thin RC walls with a single curtain of welded wire mesh fabric. The drift capacities of typical thin RC walls are estimated in a performance-based seismic design procedure for buildings with RC thin walls. [ABSTRACT FROM AUTHOR]

This paper presents the results of shaking table tests of shear wall panels made of cob materials. A proposed low-cost retrofit design was applied on one of the panels. The retrofitting was carried out with vertical bamboo sticks and horizontal layers of plastic coated steel wire mesh. A similar wall panel without retrofit was used as a control specimen. The wall panels were 1 m in height and length each with a thickness of 150 mm. The height and thickness were selected to simulate one-third model dimensions of the prototype walls employed in cob buildings in Balochistan, Pakistan. The walls were instrumented with accelerometer and string pots to measure acceleration and displacement, respectively. The decay in the dynamic characteristics of the retrofitted wall panel was less than the unretrofitted control wall panel. The displacement and acceleration of the unretrofitted control specimen increased drastically after a peak ground acceleration (PGA) of 1 g (0.33 g in the prototype domain). The acceleration response of the control specimen decreased at a PGA of 2.25 g (0.75 g in the prototype domain) and it failed by toe crushing at a PGA of 4.55 g (1.52 g in the prototype domain). No significant damage or change in the behaviour of the retrofitted wall panel was observed up to a PGA of 5.19 g (1.73 g in the prototype domain). The applied in-plane moment on the unretrofitted wall panel reached to a maximum value at a PGA of 1.23 g (0.41 g in the prototype domain) whereas the retrofitted wall was subjected to similar maximum moment at a PGA of 3.43 g (1.14 g in the prototype domain). The results clearly indicate that the proposed retrofit design is effective in improving the in-plane response of the cob shear wall and can be used for both the existing and new cob structures. [ABSTRACT FROM AUTHOR]