Advances in Civil Engineering

Researchers have increasingly used system dynamics (SD) as a modelling tool to understand the behaviour of systems with varying degrees of dynamism and complexity. SD has had a particularly significant impact in improving system representation, modelling, and abstraction of problems within the construction domain. However, there is a lack of comprehensive systematic literature review and content analysis on application of SD in construction engineering and management (CEM). In this study, a systematic literature review and content analysis were used to investigate 213 journal articles published from 1995 through 2021, presenting applications of SD in CEM research. This included analysis of SD research in terms of contributing authors and their affiliations; identifying the major CEM research areas and patterns of SD research within those areas; study of the current focus of SD research, future trends, and potential for future research in these CEM areas; investigating the SD modelling paradigm in terms of hybridization with other modelling techniques; and a review of issues and challenges of SD modelling. This study contributes to the body of knowledge by (1) addressing the lack of a comprehensive systematic review and content analysis in the application of SD in CEM research, (2) providing construction researchers and practitioners with the state-of-the-art in SD research and application within the construction industry, and (3) assessing the potential for SD hybridization with other modelling approaches and proposing areas of future research to improve SD modelling capabilities. This study found that (1) the concept of SD was mostly used in the research areas of decision making and policy analysis, performance, and rework and change, (2) the areas of scheduling and health and safety have acquired more interest in SD relative to previous trends, and (3) researchers have the lowest interest in the research area of bidding and procurement.

In order to evaluate the shear strength and behavior of high-strength concrete beams without web reinforcing, eight high-strength continuous concrete beams with cross sections of 200 mm by 300 mm were cast and tested to failure. The ultimate load-carrying capability and shear behavior are presented. The applicability of the Sudheer et al. equations and ACI 318M-14 is examined. In addition, the effects of the compressive strength () and shear span to effective depth ratio (a/d) on the shear strength and behavior of HSRC beams without stirrups are also studied. 63 MPa, 78.8 MPa, 85.9 MPa, and 92 MPa were the concrete’s compressive strengths, while 2.41 and 3.33 were its shear span to effective depth ratios. There were two equal spans of continuous beams, and at each span, they were evaluated under a single-point load. It was found that with increasing compressive strength, the failure load was increased. But the deflection did not affect it significantly. While increasing, (a/d) led to a decrease in failure load but increased deflection. It was also found that both ACI 318 M-14 and Sudheer et al. equation were more conservative.

By embedding a nonlinear nonequilibrium adsorption model considering the adsorption history (i.e., Bai model), a governing equation for the three-dimensional model is extended, which discussed the influence of varying seepage velocity and injection concentration. Compared with the previous linear adsorption model, the concentration peak value of the nonlinear nonequilibrium adsorption history model is higher than that of the linear model, and the time to reach the peak concentration is slightly earlier. In the case of horizontal seepage water, a pollution point source tends to migrate along the direction of water flow and has less ability to diffuse in the vertical direction. Compared with the adsorption history model, the linear model has a stronger blocking ability for pollutant migration, and the longer the time, the greater the gap between the two models. The longer the decay period, the wider the spread of contaminants, and the longer it takes for them to migrate out of the model completely. The more significant the head difference, the larger the diffusion area of pollutants in the main seepage direction, but it has no promotion effect on the lateral diffusion. The pollutant concentration is higher than that of the point source case, and the diffusion range in each section is wider. The closer it is to the center of the pollution source, the weaker the dispersion effect on the diffusion of pollutants in the main seepage direction, and the pollutants will spread in the countercurrent direction, causing pollution upstream.

In recent years, there have been many studies on regional geological hazard risk assessment. However, most previous research focused on natural geological disasters such as landslides and debris flows. There were few special regional risk studies aimed at highway slopes influenced deeply by artificial factors. According to the characteristics of highway slope, based on the evaluation of regional natural influencing factors, the artificial influencing factors and geological engineering information of an individual slope are introduced in this paper. The information evaluation model, combined with the analytic hierarchy process (AHP) and ArcGIS spatial analysis, was used to evaluate the risk of disaster in the study area. Then, the risk assessment results and risk zoning map along the highway were obtained. By comparing and analyzing the data of the management unit, the research results were in good agreement with the actual slope. The results of this paper can effectively guide the maintenance and management of highway slopes and provide a reference for site selection of subsequent highway reconstruction and expansion projects. In general, this study can improve the level of geological risk management in highway engineering.

In the paper, a simple-supported wooden beam is used as the research object to identify the damage of the wood beam by finite element analysis and experimental research. First, ANSYS was used to establish the solid finite element model of the wood beam before and after the damage, and then the discrete wavelet transform was performed on the curvature mode of the wood beam before and after the damage, and the wavelet coefficient difference index was obtained after obtaining the high frequency wavelet coefficients. Then, the damage location of the wood beam was judged according to the sudden peak of the wavelet coefficient difference index, and the damage degree of the wood beam was estimated by fitting the relationship between the wavelet coefficient difference index and the degree of damage. Finally, the index was verified by the wooden beam test. The results show that the wavelet coefficient difference index can accurately identify the damaged location of the wood beams. The degree of damage to the wood beams at the damage location can be quantitatively estimated by fitting the relationship between the wavelet coefficient difference index and the degree of damage at the damage location. The research results provide a theoretical basis to identify wooden beam damage.

Over the years, there have been many studies on the performance improvement of asphalt mixtures using different materials and additives, especially those of the recycled variety, because of the environmental benefits they bring to the design. This study investigated the properties of asphalt mixtures made with different amounts of calcium lignosulfonate (CLS), which is a waste product, and used the Balanced Mix Design (BMD) approach to determine the appropriate mix design for CLS-containing mixtures. In this process, the results of the dynamic creep test were used as a measure of rutting resistance, the results of the indirect tensile test were used as a measure of moisture susceptibility, and the results of the Illinois Flexibility Index Test (IFIT) and Indirect Tensile Cracking Test (IDEAL-CT) were used independently as a measure of cracking resistance. On the other hand, since previous studies have suggested that CLS has antiaging properties, the specimens were made and tested in two groups: those with long-term aging and without long-term aging. So the objective was to determine the amount of CLS that should ideally be used as a bitumen additive in aged and unaged asphalt mixtures. The results showed that using 15% or 20% CLS will always yield acceptable outcomes in terms of BMD criteria for both aged and unaged conditions. However, a CLS content of 10% may also be acceptable for both aged and unaged conditions if IDEAL-CT results are used as the measure of cracking resistance.