Engineering Characteristics of Near-fault Vertical Ground Motions and Their Effect on the Seismic Response of Bridges
A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component. The results show that both the peak value ratio and response spectrum ratio are larger than the 2/3 value prescribed in existing seismic codes, and the relationship between the vertical and horizontal ground motions is comparatively intricate. In addition, the effect of the near-fault ground motions on bridge performance is analyzed, considering both the material nonlinear characteristics and the P∼Δ effect.
The challenge of new communication architectures is to offer QoS in Internet networks. This paper investigates the QoS aspects in the NGN (Next Generation Networks), and especially in the wireless networks. Voice and video multimedia applications will be developed and used when QoS mechanisms will exist. Therefore new functions must be developed to guarantee performance, offer security, avoid jitter and to allow the respect of real-time constraints.