RESISTANT MECHANISM AND ANALYTICAL METHOD FOR RESTORING FORCE CHARACTERISTICS OF LATH-MORTAR FINISH WALL BY VENTILATION CONSTRUCTION METHOD SUBJECTED TO HORIZONTAL LOADS

A lath-mortar wall is used on conventional wooden house, and the wall using furring strips for damp proof is particularly attracting the attention because of its good durability. However, a lot of severe damage of lath-mortar wall was reported during past earthquake disasters. Also, the past studies on seismic resistant performance of lath-mortar wall were limited. This paper investigates the resistant mechanism and restoring force characteristics, and the analytical method is studied. First, to clarify the resistant mechanism and inelastic behavior of lath-mortar wall, the horizontal loading tests are done as parameter with the load distribution pattern (see Table 2). 1st story and 2nd story wall test specimen are prepared (see Figs. 1, 2), which wall is made of ventilation construction method. From test result in case of 1st story wall specimen, the slip and pinching behavior are observed (see Fig. 5). From the observation of test specimen, the remarkable damage is not appeared on mortar, however, the pull-out of staple and damage on wooden frame are observed (see Fig. 7). The rotation of lath-mortar is occurred following the shear deformation of wooden frame. And the same ratio of each deformation is presented until 1/3- rad story drift. During the ultimate state after 1/30 rad, the rotation of lath-mortar is not progressed because of pull-out and fracture of staple joint (see Fig. 6). From test results in case of 2nd story wall specimens, the slip and pinching behavior are presented (see Fig. 8). From the observation of test specimens, the lath-mortar does not show the remarkable damage, however, the pull-out of staple are occurred (see Figs. 9, 14). From the comparison of skeleton curve, the stiffness and strength show different each story (see Fig. 10, Table 3). It means that the relative displacement between lath-mortar and wooden frame presents the different trend due to load pattern (see Fig. 15). And the analytical study is done to discuss the deformation of lath-mortar wall (see Fig. 16). From the consideration of analytical expression and test results of 2nd story wall specimen, the relative displacement of staple joint presents different from each other due to the center of lath-mortar wall which is calculated with equilibrium condition. To chase the resistant mechanism of lath-mortar wall, the inelastic behavior of staple joint becomes important. Here, the elementally loading test on partial staple joint test specimen with lath-mortar is perf