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Pushover analysis is widely used in modern practical structural design to evaluate collapse modes and member forces at the safety limit state. All members, including shear walls, need to be modeled properly to assure the accuracy of pushover analysis. As such, functions to predict initial stiffness, crack strength, yield or ultimate strength, stiffness degrading ratio to the yielding point, ultimate deformation, and ultimate shear strength must be acceptably accurate. While several theoretical, semi-theoretical, and empirical functions have been proposed and are commonly used in practice, the accuracies of these functions have not been verified comprehensively. The Ministry of Land, Infrastructure, Transportation and Tourism and the Building Research Institute launched a project in Japan from 2012 to 2015 to develop a comprehensive database of experimental data from 507 reinforced concrete wall experiments conducted between 1975 to 2013 to confirm the accuracy of the functions. In this paper, the comparisons between values predicted using the functions against experimental results from the database are presented. It was found that (i) the predicted initial stiffness tends to be higher than that from experimental tests, (ii) the predicted ultimate flexural and shear strengths were generally smaller than those from experimental tests, and its accuracy appears to be dependent on the presence of boundary columns and the existence of openings, and (iii) the predicted deformation corresponding to yield and at ultimate shear strength tends to be smaller than those from experimental tests.

Following the observation of severe damage to structurally isolated non-structural reinforced concrete walls after major earthquakes, researchers began to reassess the effectiveness and connection detail of non-structural walls to moment-resisting frames. A method to control damages to the non-structural wall, is to cast exterior non-structural concrete wall elements to be monolithic with frame elements, without anchoring the wall longitudinal bar. The non-anchorage of the wall longitudinal bar significantly increases the drift capacity of the wall and decreases damage. Using an experimental approach, this study assesses the influence of reinforcement detailing and quantity of the transverse reinforcements on the strength and drift capacity of the non-structural hanging wall. This study further evaluates the workability mechanism of the transverse reinforcements and reinforcement detailing with concrete. The non-anchorage of hanging walls, having boundary confinements, was found to exhibit a higher drift and strength capacity than similar walls with the anchored detailing without boundary confinements. The strength capacity of the anchored detailing hanging walls with minimum amounts of reinforcements was higher than that of the non-anchored specimen. The boundary confinements were found to be more influential on the capability of the hanging wall when placed along with non-anchored detailing reinforcement.

Static loading tests on two full-scale reinforced concrete buildings were conducted at Building Research Institute in 2014 and 2015 to verify the effectiveness of damage control design utilizing walls. The tested buildings were five-storeys high with two bays in the direction of loading. The 2014 specimen was a moment resisting frame consisting of beams and columns with wing walls. The 2015 specimen contained wing walls, spandrels and hanging walls attached to the columns and beams. The measured strengths were much higher than the calculated strength of the bare frame without these walls. The hysteretic curves showed ductile behaviour in the 2014 specimen until ultimate drift, while strength deterioration was observed in the 2015 specimen. From the cracking pattern and the storey drift distributions within the specimens, the first specimen formed a beam sway mechanism, and the second specimen formed a mixed mechanism with column yielding between the 1st to 3rd storeys. The residual cracks of the specimens were generally wider due to the concentration of the plastic hinge region, although the damage was evaluated as slight at 0.33% drift and as minor at 0.75% based on the residual energy capacity. Damage grades evaluated from the residual energy capacity were obviously smaller than the damage grades evaluated from the residual crack widths in accordance with the damage evaluation guidelines.

In order to use a damaged building continuously after earthquake, owners and/or stakeholders need to understand residual seismic capacity of the building. In Japan, a method to evaluate residual seismic capacity for damaged buildings had been developed. In order to evaluate residual seismic capacity of damaged building, the damage level of structural elements should be evaluated properly. This paper presents the results of damage analysis based on experimental data obtained from a full-scale static loading test [1] on a five-story reinforced concrete building tested at Building Research Institute. The damage rating for the specimens evaluated by the residual seismic capacity concept [3] was ”Moderate” or ”Heavy” at 0.5% and 1% building drift angle despite the structure maintaining horizontal load carrying capacity. This implies that the applied method gives a conservative result for ductile buildings, such as relatively new moment resisting frames designed after 1981. In order to apply the method used in this paper to new buildings, the damage evaluation method for structural elements should be advanced more in the future.

Two real scale five-storey reinforced concrete frame buildings were tested in BRI in order to evaluate damage of reinforced concrete structural members such as beams, columns, and walls for strength-based design buildings. A series of experimental works show that secondary RC walls could have improved seismic performance for damage reduction by changing configuration and rebar arrangement.

In this paper, results are presented from shaking-table tests of a full-scale 10-story reinforced-concrete structure to confirm the behavior of a free-standing system with a base that permits both sliding and uplifting. The purpose of this system is to use the seismic resistance of the structure during a small or medium earthquake and a sliding and uplifting behavior of the free-standing system during a large earthquake. Cast-iron plates were installed on the grade beams of the lower part of the specimen building to generate a low friction coefficient. Thus, the specimen building should be able to move sideways during large earthquakes, although the specimen building should not move sideways during small earthquakes. In the tests, the specimen building was moved sideways during tests with JMA-Kobe 25%, 50%, and 100% amplitude excitations but not during that with JMA-Kobe 10% amplitude excitation, and the specimen building was uplifted at one of its corners for all amplitude excitations. The base sliding displacement was 84–189 mm, and the corner uplift was 5–40 mm. The sliding and uplift behavior led to small maximum inter-story drift ratios, and these behaviors did not increase the base overturning moments. Thus, allowing sliding and uplifting behavior can reduce building damage in an extremely large earthquake.