The fatigue behaviors of metals are different under in-service environment and loading conditions. This study was devoted to investigating the combined effects high low cycle loads on performance alloy steel Q345. Three kinds experiments were carried out, including pure (HCF) tests, (LCF) (HLCF) tests. prediction formulae proposed for failure. Scanning electron microscopy (SEM) stereo microscope used analyze microstructure fracture morphology due loads. Case damage a arch bridge out based FE...

To study the seismic performance of self-centering circular-section rocking steel bridge piers whose functions can be restored after an earthquake, a high-precision finite element (FE) analysis model such was established. The hysteresis behavior concrete-infilled and hollow compared. In response to characteristics local deformation wall plates elliptical bottom surface, two reinforcement methods for pier bottom, namely thickening plate adding longitudinal stiffeners in plastic zone were...

The local instability of steel plates is the predominant seismic failure mode for bridge piers. However, application shell-based finite-element (FE) models in an engineering design presents significant difficulties, and existing simplified calculation methods have their own insufficiency. In this paper, single-column square-section piers were studied to propose equivalent hysteretic model fiber elements that can consider behavior plates. Using length half-buckling wave at bottom pier as...

Based on the continuum damage mechanics model (CDM) for monotonic tension, a new CDM ultra-low-cycle fatigue (ULCF) is put forward to predict ULCF of steel and its weld joint under strong earthquakes. The base metal, heat-affected zone metal Q345qC were considered as research objects, uniaxial plastic strain threshold was calibrated via tensile testing combined with finite element analysis notched round bar specimens. tests specimens carried out analyse their life, fracture life...

Cyclic void growth model (CVGM) and continuum damage mechanics (CDM) are suitable for predicting the of ultra-low-cycle fatigue (ULCF) theoretically. However, studies on prediction is lacking. To determine which method better, we used two methods to predict ULCF. Firstly, uniaxial tensile large strain cycle tests were performed base metal, weld metal heat-affected zone material parameters calibrated respectively. The plastic threshold toughness parameter minimum, dispersion was maximum....

Mechanical properties, including the fatigue behavior of metals, are usually determined from damage-free specimens, but it is not well known how these properties change with respect to prior damages; hence, present work aims understand remaining mechanical low carbon alloy steel Q345q pre-damages. Low-cycle tests on damage free tensile low-cycle damaged and plastic deformed specimens were carried out, respectively. The life prediction formula was proposed. influences different kinds...

To propose a seismic response calculation model for eccentrically compressed steel piers that can consider the local instability effect and horizontal bidirectional earthquake actions, in-plane out-of-plane pseudo-static numerical simulation analysis are performed to study applicability of improved fiber model. The comparison results with refined hybrid-element show accurately simulate hysteretic performance in or directions be used calculate structural requirements under action rarely met...

<title>Abstract</title> The prestressed self-centering rocking steel bridge pier with external energy-dissipating devices has excellent seismic and economic performance broad application prospects. This paper establishes a prediction model for the height of compression zone at bottom based on existing statics analytical piers under horizontal cyclic load. Furthermore, dynamics Lagrange’s equation conservation theorem angular momentum before after impact, calculation method structural system...

Abstract Steel structures with thick‐walled section tend to have local fracture before the occurrence of instability under strong earthquakes, which is termed as ultra‐low cycle fatigue (ULCF). In this study, a series specimens made structural steel Q345qC for bridge in China were firstly tested investigate ULCF behaviour material level. Based on test data, three models calibrated. Subsequently, square piers also investigated component Moreover, finite element global and submodels...

Seismic performance of partially concrete-filled steel tube (PCFST) bridge piers is controlled by the coupled failure ultralow-cycle fatigue (ULCF) and local instability plates. An empirical formula was established for plastic fracture displacement on average stress triaxiality crack intiation process, two-stage prediction model ULCF cracking improved. Furthermore, an strain amplification factor element size coarse model. A complete modeling method proposed seismic analysis PCFST considering...

For an RC beam, the strength of steel rebar, bonding between concrete and reinforcement, bite action aggregates will deteriorate significantly due to corrosion. In present study, 10 beams were designed study impact corrosion on shear bearing capacity. The mechanism for stirrups longitudinal bars their effects analyzed. Based existing experimental data, correlation stirrup factor cross section loss rate was obtained. An effective prediction formula capacity corroded proposed validated by...