Abstract Probabilistic seismic demand models are a common and often essential step in generating analytical fragility curves for highway bridges. With these probabilistic being traditionally conditioned on single intensity measure (IM), the degree of uncertainty is dependent IM used. Selection an optimal conditioning not trivial matter has been focus numerous studies. Unlike previous studies that consider structure selection, this study evaluates IMs use when bridge portfolios such as would...

Abstract Bridge fragility curves, which express the probability of a bridge reaching certain damage state for given ground motion parameter, play an important role in overall seismic risk assessment transportation network. Current analytical methodologies generating curves do not adequately account all major contributing components. Studies have shown that some types, neglecting to these components can lead misrepresentation bridges' fragilities. In this study, expanded methodology...

This study evaluates the properties of superelastic Ni–Ti shape memory alloys under cyclic loading to assess their potential for applications in seismic resistant design and retrofit. Shape alloy wire bars are tested evaluate effect bar size history on strength, equivalent damping, recentering form. The both quasistatic dynamic loading. results show that nearly ideal can be obtained form alloys. However, higher strength damping compared with bars. capabilities (based residual strains) not...

This paper investigates the cogency of various impact models in capturing seismic pounding response adjacent structures. The analytical considered include contact force-based linear spring, Kelvin and Hertz models, restitution-based stereomechanical approach. In addition, a model based on law using non-linear hysteresis damper (Hertzdamp model) is also introduced for simulation. Simple approaches are presented to determine stiffness parameters models. Parameter studies performed two...

Seismic fragility curves for classes of highway bridges are essential risk assessment transportation networks exposed to seismic hazards. This study develops nine (common three-span, zero-skew with non-integral abutments) common the central and southeastern United States. The methodology adopted uses 3-D analytical models nonlinear time-history analyses. An important aspect selected is that it considers contribution multiple bridge components. results show multispan steel girder most...

Abstract Fragility curves for retrofitted bridges indicate the influence of various retrofit measures on probability achieving specified levels damage. This paper presents an analytical methodology developing fragility classes bridge systems. The approach captures impact vulnerability multiple components, which to date has not been adequately addressed, and results in a comparison system before after application different measures. Details presented include modeling, uncertainty treatment,...

Hurricane Katrina caused significant damage to the transportation system in Gulf Coast region. The overall cost repair or replace bridges damaged during hurricane is estimated at over $1 billion. This paper describes observed patterns bridges, including attributed storm surge, wind, impact from debris, scour, and water inundation, as well examples of measures used quickly restore functionality system. Using data 44 that were damaged, relationships between surge elevation, level, costs are...

This study evaluates the feasibility of a new class partially restrained connections using shape memory alloys. In martensitic form, alloys (SMAs) have ability to recover large residual deformations by heating alloy above its transformation temperature. The proposed connection consists four diameter NiTi SMA bars connecting beam flange column and serve as primary moment transfer mechanism. Two full-scale were tested SAC loading protocol. exhibited high level energy dissipation, ductility...

The 12 January 2010 M w 7.0 earthquake in the Republic of Haiti caused an estimated 300,000 deaths, displaced more than a million people, and damaged nearly half all structures epicentral area. We provide overview historical, seismological, geotechnical, structural, lifeline-related, socioeconomic factors that contributed to catastrophe. also describe some many challenges must be overcome enable recover from this event. Detailed analyses these issues are presented other papers volume.

As the use for regional seismic risk assessment increases, need reliable fragility curves portfolios (or classes) of structures becomes more important. Fragility have added complexity having to deal with uncertainty in geometric properties, along typical uncertainties such as material or component response parameters. Analysts are challenged selecting a prudent level treatment while balancing simulation and computational effort. In order address this question, study first evaluates modeling...

Relationships between bridge damage and the resulting loss of functionality are critical to assessing impact an earthquake event on performance transportation network. This study addresses this data need by use a Web-based survey central southeastern U.S. Department Transportation inspectors officials. Results 28 responses analyzed offer link various types component expected level allowable traffic carrying capacity due closure decisions repair procedures. is utilized assess probability...

Wood poles comprise a portion of the power utility's aging infrastructure that make significant impact on customer's reliability. A large number may fail under influence severe wind storms and hurricanes, sometimes resulting in millions dollars replacement costs per year to utilities. holistic approach risk assessment wood distribution networks would therefore consider simultaneous effects decay natural hazards failure probability poles. Toward this goal, paper presents framework for...

Summary Recent efforts of regional risk assessment structures often pose a challenge in dealing with the potentially variable uncertain input parameters. The source uncertainties can be either epistemic or aleatoric. This article identifies variables exhibiting strongest influences on seismic demand bridge components through various regression techniques such as linear, stepwise, Ridge, Lasso, and elastic net regressions. statistical results indicate that Lasso is most effective one...

SUMMARY This paper proposes a new set of probabilistic joint shear strength models using the conventional multiple linear regression method, and advanced machine‐learning methods multivariate adaptive splines (MARS) symbolic (SR). In order to achieve high‐fidelity with reduced model errors bias, this study constructs extensive experimental databases for reinforced unreinforced concrete joints by collecting existing beam‐column subassemblage tests from sources. Various influential parameters...

Summary Current seismic design codes and damage estimation tools neglect the influence of successive events on structures. However, recent earthquakes have demonstrated that structures damaged during an initial event (mainshock) are more vulnerable to severe collapse a subsequent (aftershock). This increased vulnerability translates likelihood loss use, property, life. Thus, reliable risk assessment tool is required characterizes undamaged structure subjected under events. In this paper,...