Results of comprehensive nonlinear response history analyses on a range configurations representing typical highway overcrossings subjected to combined effects vertical and horizontal components near-fault ground motions are reported. Current seismic design guidelines in California neglect the for peak accelerations less than 0.6g provide rather simplistic measures account when they need be incorporated design. from numerical simulations show that cause significant amplification axial force...

The 2010–2011 Canterbury earthquakes in New Zealand revealed (1) improved structural response resulting from historical design advancements, (2) poor performance due to previously identified shortcomings that had been insufficiently addressed practice, and (3) new deficiencies were not recognized because of premature failure other flaws. This paper summarizes damage concrete walls observed the February 2011 Christchurch earthquake, proposes links between specific concerns, offers suggestions...

Abstract The estimation of cyclic deformation demand resulting from earthquake loads is crucial to the core objective performance‐based design if damage and residual capacity system following a seismic event needs be evaluated. A simplified procedure develop spectrum for use in preliminary evaluation proposed this paper. methodology based on estimating number equivalent cycles at specified ductility. then determined using well‐established relationships between input energy dissipated...

Nonlinear static and dynamic analyses were used to evaluate the inelastic seismic response of bridge viaduct structures supported on extended cast-in-drilled-hole (CIDH) pile shafts. The nonlinear a beam-on-nonlinear-Winkler foundation (BNWF) framework model soil-pile interaction, fiber beam-column elements reinforced concrete sections, one-dimensional site for free-field soil profile response. study included consideration ground motion characteristics, response, lateral resistance,...

The traditional use of displacement ductility factor for damage assessment structures under high-intensity earthquake ground motion is inadequate, since it implicitly assumed that occurs only due to maximum deformation and independent the number nonpeak inelastic cycles or plastic strain energy dissipated by structure. A more recent approach, however, considers structural as a linear combination normalized energy. At ultimate limit state, decrease linearly with increase in amplitude. state...

The current approach for seismic retrofit of bridge columns in California involves extensive use steel jacketing, which has been shown to be very effective enhancing the flexural and shear performance deficient columns. In this paper, an analytical model is developed first‐yield limit state ultimate flexurally dominated steel‐jacketed circular Lateral stiffening column taken into account by considering bond transfer between jacket column. Two possible states are identified: (1) A that...

Results of an experimental program investigating the lateral strength and ductility capacity reinforced concrete piles are presented. Four full-scale with details representative current California design were tested under combined axial compression reversed cyclic displacement. Test parameters include confining steel ratio, aboveground height, soil density. Of particular interests stiffness soil-pile system, depth-to-maximum-moment, magnitude local deformation upon formation a plastic hinge...

Abstract Shear‐type buildings with Maxwell model‐based brace–damper systems are studied in this paper a primary emphasis on the effects of brace stiffness. A single‐story building viscous damper installed top Chevron‐brace is first investigated. Closed‐form solutions derived for simple structure, relating stiffness and coefficient to targeted reduction response displacement or acceleration. For given stiffness, solution minimized give set formulae that will allow optimal be determined,...

In this paper, a procedure for developing the duration-dependent inelastic seismic design spectrum is proposed. The approach assumes that lateral strength of structure can be increased to compensate number cycles may imposed on under long duration ground motion. Seismic input energy considered as part demand structure, and an empirical prediction in terms motion made. established by requiring have cyclic plastic strain capacity larger or equal portion contributing cumulative damage....

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An analytical model, based on the commonly used equivalent cantilever concept, is developed for assessing local ductility demand of a yielding pile-shaft when subjected to lateral loading. For elastic response pile-shaft, an depth-to-fixity assumed, which can be derived by equating stiffness that soil-pile system. In adapting model pile-shafts, however, depth-to-maximum-moment assumed occur at depth above depth-to-fixity. The strength, depends depth-to-maximum-moment, determined using...

Seismic performance of structures is related to the damage inflicted on structure by earthquake, which means that formulation performance-based design inherently coupled with assessment structure. Although potential for cumulative during a long-duration earthquake generally recognized, most codes do not explicitly take into account such events. In this paper, classical low-cycle fatigue model commonly used seismic cast in framework suitable incorporating design. The model, conjunction input...

Large inelastic tensile strains and wide horizontal cracks primarily caused by in-plane loading, may lead to local out-of-plane deformations of the end regions reinforced concrete (RC) walls within a buckled zone that comprises plastic hinge length. Critical parameters influence onset this failure mode have been studied through past experimental tests on RC prisms subjected axial which simulates response under demands. Missing from those studies is effect bidirectional loading protocols...

In this paper, the damage potential of an earthquake ground motion is evaluated in terms total power acceleration motion. By assuming appropriate spectral shape for input energy spectrum, and using well-known Parseval theorem evaluating a random signal, peak amplification factor equivalent velocity spectrum can be determined. It shown that depends on peak-ground-acceleration to peak-ground-velocity ratio duration strong phase Values vary from about 2 10 most recorded motions used study....

This paper uses a recently developed technique, known as the differential transformation, to determine critical buckling load of axially compressed heavy columns various support conditions. In solving problem, it is shown that transformation technique converts governing equation into an algebraic recursive equation, which must be solved together with boundary Although fairly large number terms are required for convergence solution, method nonetheless efficient and easy implement. The also...

Potentially unfavorable stress redistributions could occur in post-tensioned concrete box-girder bridges upon deck rehabilitation by an ultrahigh-performance (UHPC) overlay. The reason for such is that the forms integral part of load-resisting mechanism so rehabilitation, namely, process removing deteriorated and casting a fresh UHPC overlay, may cause large box girder. In addition, significantly different shrinkage behavior between freshly cast overlay old existing below would result...

The current American Association of State Highway and Transportation Officials (AASHTO) Load Resistance Factor Design (LRFD) Specifications impose fairly strict limits on the use its live-load distribution factor for design highway bridges. These include requirements a prismatic cross section, large span-length-to-width ratio, small plan curvature. Refined analyses using 3D models are required bridges outside these limits. place severe restrictions routine in California, as box-girder...

Under seismic loading, restraint provided by the anchorage of pile reinforcement in pile-cap a foundation may induce large curvature demand pile. For performance-based design foundation, severity local damage be controlled limiting ductility potential plastic hinge region The depends on strength and stiffness soil-pile system, as well equivalent length In this paper, kinematic model relating displacement factor to is proposed. analytical model, which amenable for wide range soil properties,...

Current practice in California requires up to a 60-day waiting period for closure pour after falsework release both staged construction and bridge widening. The relatively long is intended mitigate damage the connected deck as differential displacement develops between new previously constructed decks. current does not take into account capacity of slab, which depends on dimensions reinforcement details slab. In this paper, time-dependent deflection two bridges under was measured...