Editorial: Rock landslide risk assessment, stability analysis and monitoring for the development of early warning systems and reinforcement measures

Peer Reviewe

A FULL-SCALE MEASUREMENT OF WIND ACTIONS AND EFFECTS ON A SEA-CROSSING BRIDGE

Wind loading is critical for the large-span and light-weight structures, and field measurement is the most effective way to evaluate the wind resistance performance of a specific structure. This study investigates the wind characteristics and wind-induced vibration on a sea-crossing bridge in China, namely Donghai Bridge, based on up to six years of monitoring data. It is found that: (1) there exists obvious discrepancy between the measured wind field parameters and the values suggested by the design code; and the wind records at the bridge site is easily interfered by the bridge structure itself, which should be considered in interpreting the measurements and designing structural health monitoring systems (SHMS); (2) for strong winds with high non-stationarity, a shorter averaging time than 10-min is preferable to obtain more stable turbulent wind characteristics; (3) the root mean square (RMS) of the wind-induced acceleration of the girder may increase in an approximately quadratic curve relationship with the mean wind speed; and (4) compared to traffic load, the wind dominates the girder’s lateral vibration amplitude, while the heavy-load traffic might exert more influence on the girder’s vertical and torsional vibrations than the high winds. This study provides field evidence for the wind-resistant design and evaluation of bridges in similar operational conditions

A FULL-SCALE MEASUREMENT OF WIND ACTIONS AND EFFECTS ON A SEA-CROSSING BRIDGE

Wind loading is critical for the large-span and light-weight structures, and field measurement is the most effective way to evaluate the wind resistance performance of a specific structure. This study investigates the wind characteristics and wind-induced vibration on a sea-crossing bridge in China, namely Donghai Bridge, based on up to six years of monitoring data. It is found that: (1) there exists obvious discrepancy between the measured wind field parameters and the values suggested by the design code; and the wind records at the bridge site is easily interfered by the bridge structure itself, which should be considered in interpreting the measurements and designing structural health monitoring systems (SHMS); (2) for strong winds with high non-stationarity, a shorter averaging time than 10-min is preferable to obtain more stable turbulent wind characteristics; (3) the root mean square (RMS) of the wind-induced acceleration of the girder may increase in an approximately quadratic curve relationship with the mean wind speed; and (4) compared to traffic load, the wind dominates the girder’s lateral vibration amplitude, while the heavy-load traffic might exert more influence on the girder’s vertical and torsional vibrations than the high winds. This study provides field evidence for the wind-resistant design and evaluation of bridges in similar operational conditions

Calculation Method of Bonding Section of Joint Surface of Dangerous Rock Mass Based on Amplitude Ratio

In this study, through an analysis of vibration response characteristics of joint surface stiffness on dangerous rock mass, the relationship formula between amplitude ratio of the dangerous rock mass to the bedrock and the length of the bonding section of the joint surface is determined. The stability of the rock mass can be evaluated by combining the formula with the existing rock-mass limit equilibrium theory. This study proposes the existence of a resonance bonding length for the dangerous rock mass. When the length of the bonding section reaches the resonance bonding length, the dangerous rock mass has the largest response to the bedrock vibration. The study found that when the length of the bonding section of the dangerous rock mass is longer than the resonance bonding length, the amplitude ratio increases with the decrease of the bonding section and increases with the increase of the vibration frequency of the bedrock. When the length of the bonding section of the dangerous rock body is shorter than the resonance bonding length, the amplitude ratio decreases with the decrease of the bonding section and decreases with the increase of the vibration frequency of the bedrock. Indoor experiments were conducted by collecting the vibration time-history curves of rock blocks and stone piers and performing analysis and calculation, which proved the accuracy of the analytical results. Through the amplitude ratio of the dangerous rock mass and the bedrock, the bonding length can be calculated. This method can improve the calculation accuracy of the stability coefficient K of the dangerous rock mass

Tension Force Detection of Short Suspender by Using Laser Doppler Vibrometer

In this study, the vibration frequency of steel rod-type short suspenders simulated by three types of prestressed steel rebars with aspect ratios of 14, 20.8, and 37.8 was detected accurately and remotely by using Laser Doppler Vibrometer (LDV); then the tension force state of short suspenders was evaluated through the quadratic regression relationships between vibration frequency and tension force. The results showed that the vibration frequency of steel rod-type short suspenders increases with the increase in tension force, and there is a good correlation between vibration frequency and prestress. Furthermore, when the prestress applied is the same, the vibration frequency of short suspenders decreases with the increase of their aspect ratios, indicating aspect ratio plays a decisive role on the change of vibration frequency. The errors between the tension force obtained by experiment and tension string theoretical calculation for short suspenders are large, due to the nonrigid boundary condition. The establishment of quadratic regression relationships between vibration frequency and tension force effectively avoids the influence of various factors on the existing calculation model such as mass, stiffness, and constraint type, and makes the detection accuracy of tension force achieve 98%

Downsizing Strategy for Cars, Beijing for People Not for Cars: Planning for People

Beijing, the capital of China, is increasing enormously relative to its economy, pollution, population and dependency on private vehicles. Most of the Chinese cities are built and being built as a car-centric city. Six million cars are registered in Beijing, and with passage of time the attraction of private vehicles increases. Increasing in infrastructure the selection towards private vehicle is boosting. Municipality of Beijing is busy to use the conventional ways to solve the congestion problem rather than the smart solution, what megacities need to adopt. Beijing is second-worst in length of communing time.   This paper addresses the traffic congestion problem in the central part of the Beijing by using “Mixed Use Small Block Concept”, where the network of roads spreads like veins in a human body, and the accessibility around center is dependent on vehicle. The aim is to recover the areas from cars and give it to residential and improve their accessibility by changing the mode of travel from car to walking and cycling, and provide clear boundaries and redesign the area by using Small Block Mixed use concept. Combining the public transportation, urban planning design and Non-Motorized Transportation priority will lead the city towards livability.The right to access every building in the city by private motorcars actually the right to destroy the city.” Mumford

Multicriteria Evaluation of Transport Plan for High-Speed Rail: An Application to Beijing-Xiongan

Beijing has an enormous transportation challenge: to relieve the extreme congestion that has arisen, largely due to overpopulation. To meet this challenge, the city administration has decided to extend its territory; a new city will be planned and built. This new city, Xiongan, will reduce the burden on the capital. A new high-speed railway (HSR) line is designed to transport millions of people every day within less than an hour. This study applies the potential of Geographical Information Systems (GIS) and multicriteria methods, Analytic Hierarchy Process (AHP) and Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE II), to determine the best alternative of transportation for the new high-speed railway line between Beijing and Xiongan, comparing different ones. The methodology consists of two stages. In the first stage remote sensing datasets such as ASTER DEM and LANDSAT images and GIS software such as ERDAS IMAGINE and ArcGIS have been used to determine settlement distribution, station location, elevation model, slope percentage, vegetation percentage, and route alignment for a new high-speed railway line for better understanding of its spatial distribution pattern over the study area. The second phase of the study focusing on assessing the various alternatives of transportation has been determined, and three approaches to choosing the best alternative have been introduced. In the paper we examine criteria associated with travel and economic criteria: travel time, the number of train stops, public satisfaction with transport, the number of seats per day, connectivity, operating costs, profit, and the payback period. Six alternatives of transportation have been studied. The stops in Guan and stations in the metro’s rings have been investigated. In the second stage, the Analytic Hierarchy Process (AHP) and PROMETHEE II methods have been used to select the best alternative. The first approach uses only criteria related to the trip, as the criterion to choose the best alternative is the maximum of the net outranking flows by PROMETHEE II method; the second approach applies two independent criteria: the ratio of normalized operating costs and the normalized net outranking flows, and the ratio of the normalized payback period and the normalized net outranking flows; the third approach includes all defined criteria, and the criterion of choosing the best alternative is the maximum of net outranking flows as calculated by the PROMETHEE II method. The approaches have been analyzed with the purpose of comparing the results. The result indicates that it is expedient to have a station in Guan, which will increase the connection and connectivity among the cities while providing fast mobility options for a large number of inhabitants of Guan city. Furthermore, the result from Remote Sensing and GIS analysis demonstrates that the proposed high-speed railway line will be environmentally sustainable and is economically/socially feasible and that it will certainly attract current and future passengers because of their needs

Automated Data Processing for Monitoring Based on Median Algorithm

As introduction of the automation equipment, hardware automation level on reservoir has greatly improved. For the restriction of the software performance and technical personnel, data reorganization far failed to meet the requirements of hardware. Base on the research on domestic and foreign technique, it is concluded that a set of data transformation methods suitable for the automation system of the small and medium-sized dams. Through the median denoising processing and eigenvalue automatic statistical techniques, a large amount of data can be screened and filtered. The method can solve practical engineering problems and meet the need of automation equipment