Narrow Results

Earthquake causes wide and severe damage to building structures, due to not just the great ground motion but also secondary actions, such as impact, blast or fire, occurring after earthquake. The extreme combined loading scenario should be considered for safety of buildings and lives. Taking fire for example, the combined load can be considered as an event in which the structures are first partially damaged under an earthquake and then attacked by fire. In order to investigate the post-earthquake loading scenario, it is important to assess the partial damage caused by earthquake on different components of structures. The behavior of welded steel I-beam to hollow square tubular columns is investigated herein. A detailed experimental study is presented in which two groups of unstiffened welded steel connections, with the same configurations, subjected to static and cyclic loading are considered. The flexibility and strength of the connections are measured, while the damage phenomena and failure modes are explored during the tests. The connection damage is found to be a cumulative fracture developing process which leads to significant gradual degradation of the mechanical properties of the connection. The quantificational evaluations of the cyclic loading induced damage are also carried out to investigate the connection damage level according to different loading intensities. A finite element modeling numerical study is also carried out to validate the experimental results and a good agreement is achieved. The test results and FE modeling provide a benchmark data for the unstiffened welded connections and can be used for further investigations of the connections subjected to combined actions such as post-earthquake fire.

Earthquake causes severe damage to buildings and infrastructure, due to not only the ground motion but also secondary actions, such as impact, blast and fire which would occur after an earthquake. In order to investigate the post-earthquake loading scenarios, it is important to assess the partial damage of structures caused by earthquake. This paper presents the behavior of double-angle bolted steel I-beam to hollow square tubular column connections under static and cyclic loading. A detailed experimental study is presented in which two groups of bolted steel connections with different column wall thickness are considered. The flexibility and strength of the connections are measured, while the damage phenomena and failure modes are explored in the tests. The connection damage under cyclic loading is found to be an accumulative developing process of fracture which leads to significant gradual degradation of the mechanical properties of the connections. Quantitative evaluations of the cyclic loading induced damage are carried out to investigate the damage level of connections according to different loading scenarios. The test results herein provide a detailed understanding of the behavior of the double-angle bolted connections under seismic loading, which would be useful for further investigations under post-earthquake actions.

On 6 February 2023, an earthquake doublet occurred, the first at Kahramanmaraş Pazarcık district ($M_w=7.7$) at local time 04:17 and the second, which approximately 9 hours after the first earthquake, occurred at Kahramanmaraş Elbistan district ($M_w=7.6$) at local time 13:24 in Türkiye. It is a disaster affected 11 cities in the eastern region in Türkiye and is referred as “Disaster of the Century”. Earthquake disasters allow humanity to investigate seismic behavior under related construction details and revising the seismic codes.

The authors conducted observational research to obtain interpretive information and digital data by investigating structural damages of moderately and heavily damaged buildings from earthquake sites. In this paper, performance evaluation is done based on existence of soft storey, weak column-strong beam, deficiencies and pounding effect. Damages are classified as beam, column, beam-column joint and shear wall, infill wall, roof and scaffolding damages. Ampleness of soft storey, column damages, inadequate joint reinforcement, inadequate structural ductility and low capacity, strong beam-weak column effect, and infill wall damages have been observed from the field. As a result of field observation, structural deficiencies, irregularities and mismatching capacity design principles have been concluded as common problems of reinforced concrete buildings in the Kahramanmaraş earthquake site.