Semi-rigid behaviour of stainless steel beam-to-column bolted connections

Stainless steel is increasingly used in structural applications but there is still significant lack of experimental evidence on the moment-rotation (M-) behaviour of moment resisting beam-to-column connections. The current paper presents experimental test results obtained from full scale tests conducted on three widely used connection types i.e., double web angle (DWA), top seat angle (TSA) and top seat with double web angle (TS-DWA) connection. Considered beam, column and angle sections were fabricated using austenitic stainless steel plates and M20 high strength bolts were used for connection assembly. M- curves for all connections were carefully recorded and were used to determine initial stiffness (Ki) and moment capacity (M20mrad) for each of the connections. Eurocode 3 guidelines were used to check the classification i.e., whether or not the connections were semi-rigid in nature. Although the considered DWA connection failed to achieve partial-strength, both TSA and TS-DWA connections showed obvious semi-rigid nature despite the connection capacities were limited by bolts. In addition, extensive ductility of stainless steel ensured that all three connection types achieved a minimum connection rotation of 30 mrad, which is specified by FEMA as a requirement for earthquake design of ordinary moment frames.

ANALISIS STRUKTUR GEDUNG IRNA (INSTALASI RAWAT INAP) RUMAH SAKIT UMUM PASAMAN BARAT MENGGUNAKAN SNI BETON BERTULANG 2847:2019 DAN SNI GEMPA 1726:2019

Indonesia continues to follow the development of building standards in the world which are dynamically changing for the better and safer, both in loading regulations, planning for concrete structures, steel structures, and planning for earthquake resistance. The latest planning standard methods reviewed in this study are SNI-03-1726-2019, SNI-03-2847-2019 and RSNI-03-1727-2020 replacing SNI-03-1726-2012, SNI-03-1727-2013, and SNI-03-2847-2013. The basic difference in SNI-03-1726:2012 compared to SNI-03-1726:2019 is in the coefficients of Fa and Fv, namely the coefficient of soil sites for a long earthquake period of 1 second and in SNI-03-2847:2019 which refers to ACI 318M-14 Building Code Requirements for Structural Concrete. The results of this study found that this change in the modeling of the West Pasaman Regional General Hospital met the requirements for the SNI-03-1726-2019 earthquake design and the SNI-03-2847-2019 reinforced concrete design.

Strengthening heritage tunnels to enhance the resilience of Wellington’s transport network

Wellington city is characterised by steep hilly terrain, and as such several tunnels have been constructed since the beginning of the last century to provide critical transport access in the city. These tunnels are still used today as part of the city’s transport routes, while also being an integral part of the city’s history and heritage. Wellington is among the most seismically active areas in New Zealand. Three major active faults located within the Wellington Region and the proximity to the subduction zone are the main contributors to the high seismicity. The aging tunnels were designed and constructed prior to the advent of earthquake design standards and are subject to deterioration. Hence, they require maintenance and strengthening to ensure operational integrity and resilience to earthquake and other hazard events. Authorities have been supported by the authors in managing the risk through identifying key vulnerabilities, and prioritisation and implementation of strengthening measures. Best practice investigation and strengthening techniques have been applied through the process to ensure resilience and cost effectiveness. The paper presents case histories that highlight the value of investigations and assessment in understanding the risks, and novel strengthening measures developed to enhance resilience while preserving the heritage of the tunnels. Case histories include the seismic strengthening of the Hataitai Bus Tunnel, the Northland and Seatoun road tunnels and the investigation and assessment of the iconic Wellington Cable Car tunnels.

Seismic Fragility Relationships for Structures

Structural fragility assessment is a fundamental component of modern performance-based earthquake design and assessment processes. Major advances in fragility functions development and implementation have occurred over the past three decades.

Sicherheitstechnische Grundlagen der Erdbebenauslegung/Safety-related fundamentals of earthquake design

Die Grundlage aller Baunormen ist der Versuch materielle und immaterielle Schäden durch unsichere Bauweisen zu verhindern. Auch wenn es wünschenswert wäre, ist es doch prinzipiell unmöglich eine absolute Zuverlässigkeit und Sicherheit zu erreichen. Hierfür wird im Eurocode 0 [1] eine Grundlage geschaffen, indem eine einzuhaltende maximale Versagenswahrscheinlichkeit für die Auslegung definiert wird. Aufbauend hierauf, versuchen alle Bemessungsnormen und Berechnungsvorschriften eine Sicherheit zu erreichen, die dieser Versagenswahrscheinlichkeit entspricht. Zur genaueren Bestimmung der Versagenswahrscheinlichkeit ist die Anwendung probabilistischer Ansätze und Methoden erforderlich. Im Erdbebeningenieurwesen und bei der Erdbebenauslegung berechnet sich diese aus der Faltung der seismischen Gefährdung an einem Standort und der Verletzlichkeit (Vulnerabilität) des zu betrachtenden Bauwerks. Mit der Einführung des neuen nationalen Anhangs des Eurocode 8 für die Erdbebenauslegung (Juli 2021) [2] und den damit verbundenen neuen nationalen und europäischen seismologischen Erkenntnissen (u. a. GFZ [3], SERA [4]) soll das Sicherheitsniveau und die zugehörige Versagenswahrscheinlichkeit von nach Eurocode 8 ausgelegten Bauwerken im Rahmen dieses Beitrags vereinfacht bestimmt und verglichen werden. Hierfür wird das Sicherheitsreservefaktorverfahren, welches zur sicherheitstechnischen Bewertung von kerntechnischen Anlagen verwendet wird, vereinfacht angewandt. Es zeigt sich, dass das im Eurocode 0 geforderte Sicherheitsniveau für die Erdbebenauslegung nach Eurocode 8 nicht erreicht wird.

Comparison between the previous and new earthquake design standards in Thailand

<p>This study was conducted on the seismic performance of the new DPT 1301/1302 - 61 earthquake design standard in Thailand, the ACI 318-11:2014, and the ASCE 7-16 Standard. The selected sample structure for the case study was an existing five-storey building located in Bangkok. It was designed as a shopping mall having a length of 350 m, a width of 35 m, and a height of 26 m, resulting in a total constructed usable area of 62,000 m2, and consists of shops, restaurants and car-park spaces. Construction started on 15th February 2013, and it was opened on 31st August 2019. Bangkok is situated on a large plain underlain by the thick alluvial and deltaic sediments of the Chao Phraya Basin. The design spectral accelerations, as specified in the previous DPT standard 1302 - 52, were established based on the data of the site characteristics available from the past. However, recent studies have revealed several key features of the site characteristics that are essential for improvement of the previous standard. The structural analysis and design of this building were performed by using computer software programs so as to comply with the previous standard. This paper presents a comparison between the previous and the newly revised standards and examines the design differences by using the selected building as a case study on the structural design of typical existing low-rise buildings in Bangkok.</p>

WOODEN STRUCTURES

The NMIT Arts & Media Building in Nelson, New Zealand is the first in a new generation of multi-storey timber structures. It employs a number of innovative timber technologies including an advanced damage avoidance earthquake design that is a world first for a timber building. Aurecon structural engineers are the first to use this revolutionary Pres-Lam technology developed at the University of Canterbury

Should we build better? The case for resilient earthquake design in the United States

America seems to have an earthquake investment gap, paying billions more annually on average to recover from earthquakes than it invests to prevent losses beforehand. Two large studies for Federal Emergency Management Agency (FEMA) and the US Geological Survey (USGS) offer insight into how well American buildings will resist future catastrophic earthquakes. They suggest that the public prefers new buildings to do more than to assure life safety, which has been the building code’s historic objective. They also suggest that greater resilience would better serve society’s economic interests. People expect to be safe in new buildings and the building code delivers safety. But people also want to use buildings after the Big One. America has a few options for meeting those expectations, including stronger, stiffer construction, with geographically optimized strength and stiffness. Greater strength and stiffness is not the only option to improve resilience, but such an approach offers the advantages that it could be implemented in practice by any structural designer without requiring additional technical expertise, software, of proprietary technology. It would produce a healthier economy and save society an average of $4 for every $1 of added cost. The savings cross property lines, benefiting tenants, owners, lenders, developers, and everyone who does business with them. The added cost would amount to approximately 1%, and experience in Moore, Oklahoma, shows that it would probably affect real estate sales and prices little or not at all. The solution addresses ethical considerations by responding to the public’s expectations for better performance and by optimizing utilitarian outcomes. Other options such as second-generation performance-based earthquake engineering, innovative technologies, and rating systems could complement this approach and further increase resilience.