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Under different ground motion excitation modes, the spatial coupling effect of seismic response for the arch bridge with thrust, seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.

Taking a 490 m deck type railway steel truss arch bridge as the background, the dynamic calculation model of the whole bridge was established by SAP2000 software. The seismic response analyses under one-, two- and three-dimension (1D, 2D and 3D) uniform ground motion excitations were carried out.

For the steel truss arch bridge composed of multiple arch ribs, any single direction ground motion excitation will cause large axial force in the chord of arch rib. The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation. The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation. For the bottom chord of arch rib, the arch foot is the weak part of earthquake resistance, but for the upper chord of arch rib, the arch foot, arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts. The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force, but the normal stress of the upper chord of the arch rib is caused by the axial force, in-plane and out of plane bending moment.

The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges.

Because of the extensive use of long‐span structures in modern engineering, much attention has been given to the extent to which ground motion phase‐lags affect the internal forces of such structures. In this paper, this problem is studied from the aspect of random seismic analysis, i.e. the random seismic responses of long‐span structures are explored with the phase‐lags of the ground joints of the structures taken into account. The earthquake is regarded as a stationary random process. Formulae for calculating the random responses of the structural displacements and internal forces are derived. Numerical examples are presented which illustrate some basic features of such random response, and also show that the ground motion phase‐lags have considerable effects on structural safety analysis.

This article examines the economic impact of a major California earthquake, by focusing on the catastrophic damage to residential real estate. It asserts that the damage, although substantial, would be small relative to the U.S. GNP. The author also asserts that the risk can be optimally allocated through reasonably priced insurance contracts and well‐functioning insurance derivative markets.

A novel frequency domain approach, which combines the pseudo excitation method modified by the authors and multi-domain Fourier transform (PEM-FT), is proposed for analyzing nonstationary random vibration in this paper.

For a structure subjected to a nonstationary random excitation, the closed-form solution of evolutionary power spectral density of the response is derived in frequency domain.

The deterministic process and random process in an evolutionary spectrum are separated effectively using this method during the analysis of nonstationary random vibration of a linear damped system, only modulation function of the system needs to be estimated, which brings about a large saving in computational time.

The method is general and highly flexible as it can deal with various damping types and nonstationary random excitations with different modulation functions.

As a practical engineering method, earthquake response spectra play an important role in seismic hazard assessment and in seismic design of structures. However, the computing scale and the efficiency of commercial software restricted the solution of complex structures. There is a clear need of developing large-scale and highly efficient finite element procedures for response spectrum analysis.

In this paper, the kernel theories for earthquake response spectra are deduced and the corresponding parallel solution flow via the modal superposition method is presented. Based on the algorithm and the parallel data structure of JAUMIN framework, a parallel finite element (FE) solution module is established. Using the solution procedure on a supercomputer equipped with up to thousands of processors, the correctness and parallel scalability of the algorithm are evaluated via numerical experiments of typical engineering examples.

The results show that the solution module has the same precision as the commercial FE software ANSYS; the maximum solution scale achieves 154 million degrees of freedom (DOFs) with a favorable parallel computing efficiency, going far beyond the computing ability of the commercial FE software.

The solution scale in this paper is very challenging for the large-scale parallel computing of structural dynamics and will promote the dynamic analysis ability of complex facilities greatly.

Timely detection of emergency events and effective tracking of corresponding public opinions are critical in emergency management. As media are immediate sources of information on emergencies, the purpose of this paper is to propose cross-media analytics to detect and track emergency events and provide decision support for government and emergency management departments.

In this paper, a novel emergency event detection and opinion mining method is proposed for emergency management using cross-media analytics. In the proposed approach, an event detection module is constructed to discover emergency events based on cross-media analytics, and after the detected event is confirmed as an emergency event, an opinion mining module is used to analyze public sentiments and then generate public sentiment time series for early warning via a semantic expansion technique.

Empirical results indicate that a specific emergency can be detected and that public opinion can be tracked effectively and efficiently using cross-media analytics. In addition, the proposed system can be used for decision support and real-time response for government and emergency management departments.

This paper takes full advantage of cross-media information and proposes novel emergency event detection and opinion mining methods for emergency management using cross-media analytics. The empirical analysis results illustrate the efficiency of the proposed method.

The proposed method can be applied for detection of emergency events and tracking of public opinions for emergency decision support and governmental real-time response.

This research work contributes to the design of a decision support system for emergency event detection and opinion mining. In the proposed approaches, emergency events are detected by leveraging cross-media analytics, and public sentiments are measured using an auto-expansion of the domain dictionary in the field of emergency management to eliminate the misclassification of the general dictionary and to make the quantization more accurate.

An analytical investigation is performed on zipper-braced frames. Zipper-braced frames are an innovative bracing system for steel structures. Conventional inverted-V-braced frames exhibit a design problem arising from the unbalanced vertical force generated by the lower story braces when one of them buckles. This adverse effect can be mitigated by adding zipper columns or vertical members connecting the intersection points of the braces above the first floor.

This paper critically evaluates over strength, ductility and response modification factors of these structures. To achieve the purpose of this research, several buildings of different stories are considered. Static pushover analysis, linear dynamic analysis and nonlinear incremental dynamic analysis are performed by OpenSees software concerning ten records of past earthquakes.

Also, ductility factor, over strength factor and response modification factor, has been calculated for zipper-braced frames system. The values of 3.5 and 5 are suggested for response modification factor in ultimate limit state and allowable stress methods, respectively.

The fragility curves were plotted for the first time for such kind of braces. It should be mentioned that these curves play significant roles in evaluating seismic damage of buildings.

Increasing awareness of the society and complying with design requirements of building codes for seismic safety of structures and inhabitants during severe earthquakes are the primary purpose of seismic analysis. This study aims to present the variability in seismic fragility functions for frames of different heights for the most vulnerable condition of structure using nonlinear time history analysis.

A total of 4, 8 and 20 stories reinforced concrete (RC) moment-resisting two-dimensional frames are considered for this study. Ground motions (GM) are selected as per the conditional mean spectrum and these are conditioned on a target spectral acceleration at the concern time period. RC frames are designed and detailed as per Indian standards. A concentrated plasticity approach is adopted for non-linear analytical modeling of the RC frames. Deterministic capacity limit states in terms of maximum inter-story drift ratio are considered for different damage states. Fragility functions have been derived following a lognormal distribution from incremental dynamic analysis curves. Finally, the maximum likelihood estimation of the response is obtained for fitting curves with observed fragility.

The fragility functions of the three structures reflect that under critical or extreme conditions of GM the taller buildings have higher fragility than the shorter buildings for each level of limit states even though both are designed to meet their code-level design forces.

The study is conducted on the extreme scenario of GM conditioned on the fundamental time period of each building, whereas comparison can be developed by selecting various methodologies of GM set. The probabilistic capacity model can be developed for future studies to check the fragility variation with deterministic and probabilistic capacity.

The investigation endeavors to present a comprehensive fragility assessment framework by analytical method. The outcome will be useful in the development of a disaster management strategy for new or old buildings and the response of seismic force with a variation of the building’s height. The findings will also be useful for updating the earthquake-resistant building codes for the new building construction in a similar context.

Inspired by the comparison of charity donations among candidates in rural elections, the authors linked the non-profit motives of charity to corporate pollution emissions. And on this basis, the authors aim to provide theoretical and empirical explanations for the relationship between corporate philanthropy and pollution. The authors find that the desire to pursue more pollution emissions stimulates the firm's philanthropy, which is similar to the public welfare donations in rural elections.

Firstly, the authors construct a game-theoretical framework consisting of an entrepreneur and a bureaucrat to study the environmental cost of corporate philanthropy through the impact on pollution emission by the firm. Secondly, the authors used various empirical methods, including hybrid OLS, IV-2SLS, PSM, etc., to empirically test the impact of a firm's philanthropy on corporate pollution emissions. Finally, the authors use the output and abatement input as intermediary variables and apply the intermediary effect model to test the impact mechanism between corporate philanthropy and corporate pollution emissions.

Theoretical model finds that the firm invests more in philanthropy discharges more emissions when the theoretical model is in political equilibrium. Besides, empirical results show that corporate philanthropy will lead to more pollution emissions by reducing abatement input and increasing production. Finally, the heterogeneity test finds that compared with state-owned enterprises, the intention of non-state-owned enterprises' philanthropy for more pollution emission is more obvious. Moreover, the improvement of regional environmental regulation can significantly inhibit the realization of corporate philanthropy's poor motive.

The results have obvious policy implications for China's future policy-making. Firstly, regulatory agencies should pay close attention to the charitable behaviors of firms with serious negative environmental externalities, and prevent them from replacing more pollution emissions with philanthropy. Besides, due to weak environmental supervision in rural areas, rural polluting enterprises will be more inclined to make charitable donations to the village collective to obtain more emission rights. Therefore, the government should strengthen environmental supervision in rural areas to prevent enterprises from wanton pollution.

By constructing a game-theoretical framework consisting of an entrepreneur and a bureaucrat, the authors expound on corporate philanthropy's pollution motivation and decision-making mechanism for the first time in theory. Besides, this paper finds that the desire to pursue more pollution emissions also stimulates the firm's philanthropy. This paper expands the literature on corporate charitable donation motivations.

In order to make sure of the safety of a long-span suspension bridge under earthquake action, this paper aims to study the traveling wave effect of the bridge under multi-support excitation and optimize the semi-active control schemes based on magneto-rheological (MR) dampers considering reference index as well as economical efficiency.

The finite element model of the long-span suspension bridge is established in MATLAB and ANSYS software, which includes different input currents and semi-active control conditions. Six apparent wave velocities are used to conduct non-linear time history analysis in order to consider the seismic response influence in primary members under traveling wave effect. The parameters α and β, which are key parameters of classical linear optimal control algorithm, are optimized and analyzed taking into account five different combinations to obtain the optimal control scheme.

When the apparent wave velocity is relatively small, the influence on the structural response is oscillatory. Along with the increase of the apparent wave velocity, the structural response is gradually approaching the response under uniform excitation. Semi-active control strategy based on MR dampers not only restrains the top displacement of main towers and relative displacement between towers and girders, but also affects the control effect of internal forces. For classical linear optimal control algorithm, the values of two parameters (α and β) are 100 and 8 × 10–6 considering the optimal control effect and economical efficiency.

The emphasis of this study is the traveling wave effect of the triple-tower suspension bridge under multi-support excitation. Meanwhile, the optimized parameters of semi-active control schemes using MR dampers have been obtained, providing relevant references in improving the seismic performance of three-tower suspension bridge.