# Experimental Study on Out-of-Plane Seismic Performance of New Type Masonry System
## 1 Introduction  
Unreinforced masonry (URM) buildings are the most representative construction system, since the early ages of mankind. Most of them are constructed without the consideration of earthquake design requirements or reference to any particular design code. It is common that total or partial collapse of URM buildings occurs during an earthquake, due to poor quality of materials and construction technology, as shown in Figures 1 and 2 (e.g., [1; 2; 3; 4; 5; 6]). The low tensile strength, low ductility, and low ability to dissipate energy are the main reasons for limiting the use of URM in middle- and high-seismicity regions. On the other hand, masonry has several advantages as a structural material, such as thermal and acoustic efficiency, economy, simple construction technology, excellent fire behavior, and, usually, low embedded energy. Masonry has good durability and adequate performance, with respect to healthy indoor environment, and can be effectively considered as an alternative low-cost construction solution to low to medium rise residential buildings. Increasing interest in this construction technique, in the last few decades, has resulted in many experimental tests on in-plane URM sub-assemblages [7; 8; 9; 10; 11] and in-plane URM buildings [12; 13; 14; 15; 16; 17; 18]. These studies have provided significantly valuable insights into in-plane seismic performance on URM buildings. On the other hand, in recent decades, there has been an increasing number of investigations focusing on the out-of-plane behavior (e.g., [19; 20; 21; 22]). Despite the fact that masonry walls are widely used in all over the world, there is only a limited number of experimental studies addressing the out-of-plane behavior of masonry walls [23; 24]. Thus, the knowledge of their behavior and design provisions is limited. In general, URM walls exposed to horizontal loads perpendicular to their plane are the most vulnerable elements, in terms of failure mechanisms, as evidenced by post-earthquake damage observations of both public and private buildings [13; 14; 16; 17; 18; 25]. Due to the out-of-plane vulnerability of URM walls, and the need to understand their behavior, a few experimental studies have been conducted in the past (e.g., [3; 4; 26; 27; 28; 29]). Furthermore, some studies on mortar-free masonry units, considering the interlocking mechanism, have been conducted (e.g., [30; 31; 32; 33]). However, most of the studies are on brick units with unevenness; there is no study targeting block units, this study does. Under these backgrounds, the authors developed two types of new block systems, consisting only of main and key blocks, without joint mortar, in consideration of seismic performance and workability. Two types of block systems have different key block shapes. One is the peanuts shape, and the other is the H shape. It is expected that the proposed  
Figure 1: Masonry wall damage of West Java earthquake, Indonesia (2009). Figure 2: Masonry wall damage of Northern Osaka earthquake, Japan (2018). masonry wall system will be applied mainly to low-rise masonry houses, masonry fences, and infilled masonry walls in developing countries. In the previous study, the proposed two types of concrete block walls, as well as a typical concrete block walls, were experimentally investigated to evaluate the in-plane seismic performance. In the tests, full-scale, single-story specimens were tested under static cyclic in-plane loading, and failure patterns and cracks were carefully observed [34]. In this study, in order to evaluate the out-of-plane seismic performance of the proposed block systems, two types of the proposed block walls were experimentally investigated, including the typical block wall. Firstly, the shaking table tests were carried out to investigate the fundamental, out-of-plane behaviors of three specimens.