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Highlights • Drift in CBFs designed to EC8 is dependent on mean ground motion period. • Increased drifts when ratio of mean period to fundamental structural period is low. • In these cases numerically calculated drifts can exceed values predicted by codes. • Regression models developed to peak predict global and inter-storey drift in CBFs. Abstract The influence of mean ground motion period, T m , on the inelastic drift response of steel Concentrically Braced Frame (CBF) structures designed to Eurocode 8 is investigated. Incremental dynamic analysis is performed for a set of case study frames with varying structural characteristics at four different seismic intensity levels. From the results of these analyses, regression models for predicting both global and inter-storey drift are developed. It is shown that that both global and inter-storey drift tend to increase nonlinearly as the ratio of fundamental structural period to mean ground motion period, T 1 / T m , decreases below unity. The rate of this increase is dependent on the ground motion intensity, represented by the EC8 behaviour factor q. The first mode participation factor, relative storey stiffness and column-to brace stiffness are also shown to influence inter-storey drift response. The values of drift predicted by the developed regression models are compared to values predicted by design codes as well as other predictive models developed in previous studies. It is observed that design codes can under predict drift at lower T 1 / T m values. [ABSTRACT FROM AUTHOR]

Highlights • The impact of the target spectrum on the acceleration causing collapse is investigated. • The impact of the number of ground motions on structural response is investigated. • Several MDOF and SDOF models are considered in the study. • A minimum of 15 ground motions should be used for time-history analysis. • The CS offers 1.2–2.3 times larger accelerations causing collapse than the UHS. Abstract The impact of the type of target response spectrum and the number of ground motions on the response of buildings is investigated. The parametric study involves the selection of ground motions based on the Eurocode 8 spectrum, a conditional spectrum using the official seismotectonic model of Slovenia, a uniform hazard spectrum based on the seismotectonic model of the SHARE project, and the corresponding conditional spectrum. In addition to the variation of the target response spectrum, the number of selected ground motions was varied from 7 to 60. Selected sets of ground motions were used to investigate the seismic response of eight reinforced concrete buildings with fundamental vibration periods from 0.15 s to 1.76 s. The aim of the study was to analyse the variation of target displacements obtained by a pushover-based method, i.e. the median displacement corresponding to a seismic intensity with a return period of 475 or 2475 years, and the median spectral acceleration causing collapse, which was estimated by incremental dynamic analysis. It was found that the target spectrum and the number of ground motions have a limited impact on the target displacement, especially if it corresponds to seismic intensities with a return period of 475 years. Additionally, the impact of the number of ground motions on the median spectral acceleration causing collapse is much lower than the impact of the target response spectrum. When the conditional spectrum was used as the target spectrum for ground motion selection instead of the design response spectrum prescribed by Eurocode 8, the resulting median spectral acceleration causing collapse increased by a factor of between 1.2 and 2.3. [ABSTRACT FROM AUTHOR]

Highlights • The details of the project of a 6-storey CLT building are presented. • The design for gravity and seismic loads is discussed in detail. • A recently developed proposal of revision of the timber chapter within the Eurocode 8 on seismic design is applied. • The design of the anchoring connections to the concrete foundation for multi-storey timber buildings is discussed. • Some details are also given regarding construction issues and fire design. Abstract This paper presents the design and construction of a six-storey residential cross-laminated timber (CLT) building in Florence, Italy. The different phases of the design process are described in detail, together with the production, transportation and on-site construction. Special emphasis is given to the seismic design, where a recently developed proposal for the revision of the Eurocode 8 has been applied, demonstrating its feasibility. Some design and construction issues are also addressed, including the connection of hold-down anchors to the concrete foundation. This connection represents the weakest link of the traditional commercial connectors used for CLT buildings, especially concerning the seismic design. [ABSTRACT FROM AUTHOR]

Water towers are widely used in our society as one of water distribution facilities within water network systems. In the event of a severe earthquake, however, a single plastic hinge that occurs in a water tower could cause its total collapse before nonlinear resources of the rest of the tower remains fully utilised. This research presents an innovative technique for the assembly of a water tower using the slits in its reinforced concrete shaft for the purpose of mitigating the seismic response. Slit shafts were designed to have four slits at 90° intervals along the full height of the shafts. The shaft parts were connected to each other at the bottom, top and every five meters with coupling beams. The slit width was used as a variable in this study which varied between 50 mm and 2000 mm. The nonlinear seismic performance of the proposed slit towers was analysed by means of a finite element approach with respect to soil types defined in Eurocode 8 and seismic behaviour were compared to the solid water tower. A detailed observation of the compression and tension stress distributions with respect to the slit width was performed. The obtained analytical results revealed that slit width in the reinforced concrete tower affect the failure mode and stiffness of a water tower significantly. With an appropriate design, the conversion of a solid water tower into a slit tower can significantly increase its ductility under seismic action without significantly compromising its bearing capacity. The results showed that contours of tension and compression stress intensity in shafts, which could lead to a failure of water towers, highly depended on the slit width. In the solid water tower, the stress concentration dominated at the base of the shaft, however in the narrow slit water towers the stresses were equally distributed along the height of the shafts. Also, the stresses were mostly concentrated at the top of the shafts in the wide slit water towers. Conclusively, the results provided useful information regarding the compression stress distribution along the slit shafts in the water towers which can be used in obtaining an optimum slit shaft design for different soil types. [ABSTRACT FROM AUTHOR]

Several research studies have proved the beneficial effects resulting from the presence of moment resisting frames and braced frames in dual structural systems. Nonetheless, Eurocode 8 provides design rules only for dual systems with moment resisting frames and concentrically braced frames and thus ignores that moment resisting frames may beneficially combine with other types of braced frames. In this paper, a design procedure for dual systems with moment resisting frames and eccentrically braced frames is proposed based on the current design provisions of Eurocode 8 for dual structures with moment resisting frames and concentrically braced frames. To evaluate the effectiveness of the proposed procedure, the seismic response of the designed systems is evaluated through incremental nonlinear dynamic analysis. The buildings considered are founded on hard or soft soil and are characterised by different values of the link length and number of storeys. [ABSTRACT FROM AUTHOR]

A significant number of existing reinforced concrete building structures were designed and built before 1970, prior to the enforcement of modern seismic design codes. The response of these structures when subjected to cyclic loads, such as that induced by earthquakes, is strongly influenced by the bond properties between the reinforcing bars and the surrounding concrete. This paper describes the results of a testing campaign composed of seven unidirectional cyclic tests and one monotonic test performed on full-scale columns built with plain bars, without adequate reinforcement detailing for seismic demands. An additional unidirectional cyclic test was carried out on a specimen with deformed bars for reference. The influence of bond properties, a cold joint at the base, lapping of longitudinal reinforcing bars, amount of reinforcing steel, cross-section dimensions and imposed loading history (monotonic or cyclic) is discussed. Finally, a correction coefficient to the expressions of EC8-3 for the calculation of ultimate rotation capacity of columns with plain reinforcing bars is proposed. [ABSTRACT FROM AUTHOR]