Structural response prediction with desirable accuracy is considerably essential for the health monitoring of bridges. However, it appears to be difficult in accurately extracting structural response features on account of complex on-site environment and noise disturbance, resulting in poor prediction accuracy of the response values. To address this issue, a Transformer-based bridge structural response prediction framework was proposed in this paper. The framework contains multi-layer encoder modules and attention modules that can precisely capture the history-dependent features in time-series data. The effectiveness of the proposed method was validated with the use of six-month strain response data of a concrete bridge, and the results are also compared with those of the most commonly used Long Short-Term Memory (LSTM)-based structural response prediction framework. The analysis indicated that the proposed method was effective in predicting structural response, with the prediction error less than 50% of the LSTM-based framework. The proposed method can be applied in damage diagnosis and disaster warning of bridges.

A buckling-restrained brace (BRB) serves as a typical load-bearing and energy-dissipative device for the passive control of structures under seismic loading. A BRB is generally designed to not yield under frequently occurring earthquake (FOE) and wind loads, resulting in it having less effectiveness in vibration reduction compared with post-yielding performance. To address this dilemma, this study proposed the concept and technique details of the viscoelastic-yielding compounded BRB (VBRB). Different from a conventional BRB, a VBRB is fabricated by attaching the viscoelastic damper (VED) to the surface of a BRB’s steel casing, ensuring a compatible deformation pattern between the VED and the BRB’s steel core. A dynamic loading test of VBRB specimens was carried out in which 0.2 Hz~0.6 Hz in loading rate and a maximum of 550 kN in load-bearing capacity had been applied, verifying the feasibility and performance of the VBRB. Subsequently, a parametric design procedure was developed to determine the required VBRB parameters so that the maximum elastic drift response of the structure could be reduced to the code-prescriptive value. The wind-resistance and seismic performances of the VBRB were critically evaluated through dynamic time-history analyses on a 48-story mega VBRB-equipped frame designed according to the Chinese seismic design code (GB50011-2010), and the effectiveness of the approach was also verified. Results indicate that the VBRB has advantages over a conventional BRB by providing a multi-stage passive energy dissipation capacity, resulting in a better vibration-control effect than conventional BRBs for structures subjected to wind load and seismic excitations.

Buckling-restrained brace (BRB) is a dual-function device that improves the seismic resistance and energy-dissipation capacity of structures in earthquake engineering. To achieve the expected performance under severe ground motions, BRB is usually designed to remain elastic under mild earthquakes, leading to the increased seismic forces and insignificant vibration-reduction effect on the structures at this stage. This study extends the concept of adaptive passive-control of structures by proposing a novel frictional-yielding compounded BRB (FBRB). FBRB is fabricated by connecting the BRB steel casing and end plates with the friction dampers (FDs) in such a way that the BRB steel core and FDs undergo compatible deformation. In this way, FD dissipates seismic energy under mild earthquakes, while FD together with the BRB core dissipates energy under severe ground motions, resulting in an efficient self-adaptive vibration-reduction mechanism. The proposed FBRB construction was experimentally validated by carrying out the reversed-cyclic test, and the result indicated reliable connection with stable hysteretic behavior. Subsequently, the FBRB-equipped frame was proposed and studied which adopted FBRB as the energy-dissipative devices. A parametric design method was developed to determine the FBRB parameters with which the maximum elastic drift of the system could be reduced to the code-allowable value. The approach was implemented on a 48-story mega FBRB-equipped steel frame as the case study. The seismic behavior of the FBRB-equipped case structure was compared with that of the BRB-equipped system, and critically evaluated by carrying out the nonlinear time-history analyses. Results revealed that FBRB compensated for the conventional BRB in terms of inadequate energy dissipation under mild earthquakes and, meanwhile, was more efficient than the conventional BRB in reducing the lateral drifts under severe ground motions. The analysis indicated potential application prospect of FBRB in practical engineering.

A new non‐finite element friction model for tube hydroforming corner fill analysis has been introduced. The proposed model, which is applicable to 90‐degree die corners, is based upon geometric considerations and does not require an incremental solution scheme. Hoop strain distributions are evaluated using both FEA and the proposed theory. Overall correlation between the FEA and proposed solutions is quite respectable in light of the fact that the proposed friction model is based upon a non‐finite element theory which does not account for the intermediate deformation. This paper helps lay the groundwork for improvements in numerical modeling of friction effects on the hoop strain distribution in tubular hydroforming corner fill analysis when closed form solutions are required. The long term‐intent of this effort is to mold the proposed theory into a form that is accommodating to a more global contact model.