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The service environment of concrete in the marine environment is harsh, and demands regarding the durability of marine concrete have increased. Marine concrete in harbor and wharf areas suffers from the combined effect of fatigue load, dry–wet cycles, and Cl− erosion, which can result in spalling of the concrete surface, corrosion of the internal reinforcement, and even concrete damage. This paper reviews recent research results on the durability of concrete and reinforced concrete (RC) under the combined effect of fatigue load, dry–wet cycles, and Cl− erosion. We further assess the variation in Cl− transport properties with fatigue load, the causes behind the reduction in the carrying capacity of RC products under fatigue load, the methods of Cl− erosion on concrete under the pressures imposed by dry–wet cycles, and the damage of the protective layer of concrete due to accelerated Cl− erosion caused by the action of dry–wet cycles. Further studies are needed on the durability of concrete under the action of fatigue load, wet and dry cycles, and Cl− erosion, in addition to the testing of the durability of concrete under the combined effects of the afore-mentioned various factors. [ABSTRACT FROM AUTHOR]

The reinforced concrete (RC) frames with masonry infill walls are always subject to in-plane (IP) and out-of-plane (OOP) interaction under earthquakes, and IP damage will affect OOP seismic performance. In order to study IP and OOP interaction of the masonry infill walls with opening in RC frames, we establish a finite element model of RC frame with solid and opening infill walls based on existing tests. We simulated the influence of opening rate and opening aspect ratio on IP and OOP interaction of RC frames with masonry infill walls. The results show that IP damage significantly reduces the OOP stiffness of the RC frames with masonry infill walls; The IP storey drift between 0.5%–2%, the OOP stiffness is reduced by 58.3%–73.7%; Under the same IP damage, the OOP bearing capacity and stiffness of RC frames with masonry infill wall in a larger opening rate has greater degradation level and faster degradation rate; For a given opening rate, the opening with an aspect ratio that closer of infill wall has the least influence on the IP and OOP interaction. Finally, based on the simulation results, a two-parameter exponential equation is found to describe the relationship between the OOP bearing capacity reduction, IP storey drift and the wall opening rate. [ABSTRACT FROM AUTHOR]

Abstract The seismic resilience of a system includes not only the consequences directly related to the intensity of earthquake but also the recovery process and time closely related to the human and government responses in the post-earthquake environment, in which many aftershocks would affect the mainshock-damaged systems. This manuscript proposes a resilience loss factor to incorporate the effects of aftershocks on the resilience loss of structures. This factor is applied on the evaluation of resilience loss for a case-study reinforced concrete (RC) frame structure under mainshock-aftershock (MSAS) sequences. The recovery time and pre-event functionality are introduced in the definition of the resilience loss factor, making this factor concentrate more on the intrinsic characteristics of structures during the recovery process. The replacement threshold based on the repair cost is incorporated into the definition of resilience loss factor to reflect the engineering application. The results indicate that the effects of considering replacement threshold and aftershocks on the resilience loss of structure can exceed 200% and 400% respectively, when the replacement threshold is reached. Highlights • Resilience loss factor is proposed considering the effects of aftershocks. • The normalization by recovery time and pre-event functionality are incorporated. • The replacement threshold is incorporated to reflect the engineering application. • Effects of replacement threshold and aftershocks on resilience loss are significant. [ABSTRACT FROM AUTHOR]

• A series of bidirectional pseudo-static tests on isolated infill walls in RC frames were conducted. • The effects of the in-plane and out-of-plane on the isolated infilled frames can not be neglected. • Boundary constraints affected the in-plane and out-of-plane performance of isolated infilled walls. This paper presents the findings of a series of bidirectional quasi-static tests conducted on isolated infilled frames to investigate the in-plane and out-of-plane interaction of the infills with different boundary constraints. The effects of prior in-plane damage on the out-of-plane behavior of isolated infill walls were assessed. It was found that the presence of existing cracks that developed during the in-plane loading stage had an effect on the out-of-plane cracking patterns, decreased the integrity of the isolated infills, and weakened the infill-frame boundary restraints. The behavior of isolated infill walls under combined in-plane and out-of-plane loading was also affected by the effectiveness of boundary constraints. The experimental results demonstrated that reliable boundary constraints were necessary for forming arching mechanisms and preventing rigid body motion. [ABSTRACT FROM AUTHOR]

• A new type of wall configuration to isolate infill walls from the surrounding RC frames was proposed. • Frame isolation reduces infill damage and delays the formation of beam-column joint shear failure under in-plane loading. • The new wall configuration improves the out-of-plane performance of the isolated infill walls. Masonry infill walls are vulnerable and have an adverse impact on the reinforced concrete (RC) frame structures under strong ground motions. Some retrofit schemes were proposed to address this, but their application may lead to some detrimental effects, such as the reduction of out-of-plane stability. A new type of wall configuration is presented in this paper to isolate infill walls from the surrounding RC frames with the view of limiting infill-frame interaction and providing a stable and reliable out-of-plane response. It features isolation gaps, wall reinforcement, tie columns, and steel channel tracks. The configuration is also verified experimentally through in-plane and out-of-plane tests. The results of in-plane tests indicate that the proposed wall configuration effectively reduces infill wall damage and undesirable infill-frame interaction. The results of out-of-plane tests demonstrate that the method improves the out-of-plane resistance and enhances the out-of-plane stability of the isolated infill walls. [ABSTRACT FROM AUTHOR]