Safety Risk Assessment Analysis of Bridge Construction Using Backpropagation Neural Network

The evaluation of construction safety risks has become a crucial task with the increasing development of bridge construction.This paper aims to provide an overview of the application of backpropagation neural networks in assessing safety risks during bridge construction.It introduces the situation,principles,methods,and advantages,as well as the current status and future development directions of backpropagation-related research.

Quality Control Measures of Bored Pile in Bridge Construction

In order to improve the quality of bored piles in bridge construction and ensure the overall quality of the bridge,we analyzed a series of problems in the construction process of bored piles,then propose corresponding quality control measures,in hopes of improving quality control of bored piles in bridge construction in our country.

Technologies for Asphalt Pavement Surface Testing in Road and Bridge Construction

Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.

Application of Mobile Formwork Cast-In-Situ Beam Technology in Bridge Construction

The application of mobile formwork cast-in-situ beam technology is conducive to providing quality assurance for bridge constructions.At the same time,it can improve the overall mechanization level of the construction process and further accelerate the construction progress,so as to shorten the construction period and improve the economic benefits of enterprises.In fact,this construction method has been widely applied.In order to assure a positive outcome from the use of this technology,this paper analyzes the application of mobile formwork cast-in-situ beam technology in bridge construction to provide reference.

A dynamic holographic modelling method of digital twin scenes for bridge construction

Holographic projection technology can provide a more intuitive and efficient visualization effect for a digital twin bridge construction scene.However,pre-rendering methods in the existing research work are usually used to implement holographic visualization,which is static display.The above-mentioned methods for static display have many shortcomings,such as poor adaptability,low rendering efficiency and lack of real-time.A dynamic holographic modelling approach is proposed for the augmented visualization of digital twin scenes for bridge construction.Firstly,a dynamic segmentation algorithm with adaptive screen size was designed to high-efficiently generate holographic scenes.Secondly,a motion blur control method was designed to improve the rendering efficiency of holographic scenes according to human visual characteristics.Finally,a prototype system was developed,and the corresponding experimental analysis was completed.The experimental results show that the method proposed in this article can support adaptive screen size image segmentation and real-time generation of holographic scenes for bridge construction.The amount of scene data can be reduced to more than 30%,which significantly improves rendering efficiency and reduces glare.

Precast steel—UHPC lightweight composite bridge for accelerated bridge construction

In this study,a fully precast steel—ultrahigh performance concrete(UHPC)lightweight composite bridge(LWCB)was proposed based on Mapu Bridge,aiming at accelerating construction in bridge engineering.Cast-in-place joints are generally the controlling factor of segmental structures.Therefore,an innovative girder-to-girder joint that is suitable for LWCB was developed.A specimen consisting of two prefabricated steel—UHPC composite girder parts and one post-cast joint part was fabricated to determine if the joint can effectively transfer load between girders.The flexural behavior of the specimen under a negative bending moment was explored.Finite element analyses of Mapu Bridge showed that the nominal stress of critical sections could meet the required stress,indicating that the design is reasonable.The fatigue performance of the UHPC deck was assessed based on past research,and results revealed that the fatigue performance could meet the design requirements.Based on the test results,a crack width prediction method for the joint interface,a simplified calculation method for the design moment,and a deflection calculation method for the steel—UHPC composite girder in consideration of the UHPC tensile stiffness effect were presented.Good agreements were achieved between the predicted values and test results.

A Fuzzy Logic-Based Method for Risk Assessment of Bridges during Construction

There are many potential sources of risks which may cause bridge failures and result in numerous economic and human losses during the construction of bridges. Therefore,risk assessment for bridges during construction should be taken rigorously to avert bridge failures and casualties. This article presents a fuzzy logic-based method which integrates the fuzzy analytical hierarchy process( FAHP) method based on a 3-point scale,fuzzy logic,and fuzzy set theory into a single synthetic method. In this method,the FAHP method based on a 3-point scale was used to identify and rank diverse risk factors,and fuzzy logic and fuzzy set theory were used to process inaccurate datasets including non-statistical information. After the concept and procedure of the FAHP method based on a 3-point scale were demonstrated,the proposed fuzzy logic-based method was used to perform risk assessment on the Aizhai Suspension Bridge with a main span length of1 176 m in China. The results show that the proposed method can more effectively carry out risk assessment of bridges during construction.

Study on the Installation and Construction Technology of the Transfer Stairway on the Track Platform on Bridge——Taking the Construction of the Jialing River Bridge in Zengjiayan of Chongqing City as an Example

The bridge deck on the Yuzhong side of Zengjiayan Jialing River Bridge is close to subway lines and light rail stations.It is necessary to set up transfer stairways on both sides of the bridge.The construction technology of installing and replacing with tunnel under special conditions is discussed to provide reference for bridge construction.

Discussion on Construction and Erection Technology of Bridge Precast Box Girder

At present,the precast construction technology has been widely used,especially in the process of bridge construction,where the precast box girder construction and erection technology has attracted more attention compared to other available methods.In order to effectively improve the application effect of this technology,and the overall quality of the bridge,this paper discusses the advantage and disadvantage of implementing the precast box girder construction and erection technology in the bridge construction.

Sub-1 GHz Network-Based Wireless Bridge-Monitoring System:Feature and Verification

Traditional bridge monitoring systems often require wired connections between sensors,a data acquisition system,and data center.The use of extension wires,conduits,and other costly accessories can dramatically increase the total cost of bridge monitoring.With the development of wireless technologies and the notable cost benefits,many researchers have been integrating wireless networks into bridge monitoring system.In this study,a wireless bridge monitoring system has been developed based on the Sub-1 GHz network.The main functional components of this system include sensors,wireless nodes,gateway and data center.Wireless nodes can convert analog signals obtained from the sensors to digital signals,then transmit the collected data to the gateway using the Sub1 GHz network.The gateway receives and sorts data from different wireless nodes and then forwards these data to the data center wirelessly.All collected data are processed in the data center using the data processing software developed in this study.In order to validate the performance of the wireless system developed in this study,a steel girder bridge was monitored in the field during the concrete deck construction.The field results were also compared with the theoretical values obtained from finite element models to ensure the accuracy and reliability of the wireless system.The results indicate that the wireless bridge monitoring system developed in this study is effective and affordable.The Sub-1 GHz network can be a better solution for bridges with complicated site conditions because of the extended data transmission distance.Although the power consumption can be controlled by using low-power consumption components,including the power control in software design can also dramatically reduce the system’s power consumption.

Particle swarm optimization model to predict scour depth around a bridge pier

Scour depth around bridge piers plays a vital role in the safety and stability of the bridges.The former approaches used in the prediction of scour depth are based on regression models or black box models in which the first one lacks enough accuracy while the later one does not provide a clear mathematical expression to easily employ it for other situations or cases.Therefore,this paper aims to develop new equations using particle swarm optimization as a metaheuristic approach to predict scour depth around bridge piers.To improve the efficiency of the proposed model,individual equations are derived for laboratory and field data.Moreover,sensitivity analysis is conducted to achieve the most effective parameters in the estimation of scour depth for both experimental and filed data sets.Comparing the results of the proposed model with those of existing regression-based equations reveal the superiority of the proposed method in terms of accuracy and uncertainty.Moreover,the ratio of pier width to flow depth and ratio of d50 (mean particle diameter)to flow depth for the laboratory and field data were recognized as the most effective parameters,respectively.The derived equations can be used as a suitable proxy to estimate scour depth in both experimental and prototype scales.