Near-fault seismic risk assessment of simply supported bridges

Abstract

Bridges tend to sustain excessive seismic demand (e.g. displacement) under pulse-like ground motions attributing to the effect of forward directivity, which is of high likely to occur at locations near the fault rupture. This study tries to incorporate the pulse effect into the probabilistic seismic hazard analysis (PSHA) and probabilistic seismic demand analysis (PSDA) framework, which are combined to quantify the risk of earthquake-induced damage in the near-fault location. The near-fault PSDA and PSHA are established and connected conditioned on peak ground velocity (PGV). Four sets of typical simply supported bridge types with the varying heights, representing the range of the period, are simulated by taking account the strength and stiffness degradation associated with material and geometry nonlinearity. The detailed investigation of the near-fault seismic risk is performed for these bridge models located at representative near-fault sites namely 5, 10, 15, and 20 km, respectively. The results reveal that near-field directivity effect strongly impacts the bridge damage risk with the observation of higher risk at the closer site; the bridges with the period of approximately Tp/2(pulse period) tend to experience the highest seismic risk, and the relative vulnerability of four bridge types is also compared.

Probabilistic seismic performance of pylons of a cable‐stayed bridge under near‐fault and far‐fault ground motions

“…Earthquake risk probabilistic evaluation methods have gradually developed into the core of structural and infrastructure system risk mitigation decisions 20‐23 . Plotting the fragility curve of the structure allows intuitively observing this risk probability.…”

“…Earthquake risk probabilistic evaluation methods have gradually developed into the core of structural and infrastructure system risk mitigation decisions. [20][21][22][23] Plotting the fragility curve of the structure allows intuitively observing this risk probability. The fragility curve could be established as a conditional probability table in which the structural requirement exceeds its capability under a given ground motion intensity (IM).…”

Probabilistic loss assessment of curved bridges considering the effect of ground motion directionality

“…An appropriate IM helps to sufficiently reflect the level of uncertainty in seismic demand and conduct a reliable loss estimation for the structure. An increasing number of studies have focused on the optimal IMs for the probabilistic seismic demand analysis (PSDA) of bridges and IMs such as PGA , 55 PGV 56 as well as spectral acceleration and spectral displacement at fundamental period (, ) 57 are commonly‐used ones. However, most of the aforementioned studies refer to straight bridges, and only few 24,58,59 have focused on finding the optimum IMs of curved bridges.…”

Investigation of the relationship between intensity measures and engineering demand parameters of cable-stayed bridges using intra-plate earthquakes

“…The other group of seismic parameters is defined by response spectra. Table 2 lists the 29 intensity measures implemented in this paper (Housner, 1965; Husid, 1969; Arias, 1970; Sarma and Yang, 1987; Von Thun, 1988; Bommer and Martinez-Pereira, 1999; Zhong et al , 2020). It should be noted in Table 2 that Sa (1.0) , Sv (1.0) and Sd (1.0) adopted in this study represent spectral acceleration, velocity and displacement at the high-order period 1 s of the cable-stayed bridge.…”