International Journal of Civil Engineering
Volume:14 Issue: 5, 2016

This study proposes a prediction model about the trajectories a vehicle, in isolated conditions, along a curve of a road. As we know, the road environment induces stress on users and, under certain conditions, influences driving behavior. It is of advantage then, to isolate and identify those conditions from among the numerous variables, which are actually the most significant so as to prevent or mitigate the occurrence of dangerous maneuvers. On the basis of an experiment performed using an instrumented vehicle, we collected a data base to which we subsequently applied Neuro-Fuzzy techniques for the selection of the most representative variables. We then used these data to prepare a nonlinear dynamic Hammerstein-Wiener’s model able to predict the track paths along curves. The findings were encouraging since almost all the results obtained from the validation checks proved satisfactory. This research is the first step in the identification of complex systems and could be applied in road safety measures and design of new and existing roads.

The purpose of this paper is to improve the intelligence and universality of the classical method for gating control in the SCOOT system. First, we introduce a method to identify spillovers, and use the occupancy threshold for spillover recognition to trigger this special control logic. Second, the interrelationship of the traffic flows among adjacent traffic links is analyzed. Accordingly, we present an influence rate model for upstream links of the bottleneck link and a share ratio model for the downstream links. With known threshold values for the influence rate and share ratio, we propose a rule and process for selecting the intersections that should be included in the sub-area of the gating control. Third, we determine total capacity adjustments for the incoming and outgoing streams of bottleneck links. Under the measures, the queue can be dissipated to a permissible length within a given period of time. After that, the apportion models for the total adjustments among different paths and links are presented. Therefore, the correlation coefficients of the traffic flows are between the bottleneck link and the other links. Next, we ascertain the capacity decrements and increments for the gated and benefiting streams. The optimization schemes are defined so as to calculate splits for the gated and benefiting intersections. Finally, we evaluate the advanced method using a VISSIM simulation. The results show that a new control method brings significant and positive effects to the bottleneck link itself and to the entire test area.

A fast converging and fairly accurate nonlinear simulation method to assess the behavior of reinforced concrete columns subjected to static-oriented pushover force and axial loading (sections under biaxial-bending moment and axial loading) is proposed. In the proposed method, the sections of column are discretized into “Variable Oblique Finite Elements” (VOFE). By applying the proposed oblique discretization method, the time of calculation is significantly decreased, and since VOFE are always parallel to neutral axis, a uniform stress distribution along each oblique element is established. Consequently, the variations of stress distribution across an element are quite small which increases the accuracy of the calculations. In the discretization of section, the number of VOFE is significantly smaller than the number of “Fixed Rectangular Finite Elements” (FRFE). The advantages of using VOFE compared to FRFE are faster convergence and more accurate results. The nonlinear local degradation of materials and the pseudo-plastic hinge produced in the critical sections of the column are also considered in the proposed simulation method. A computer program is developed to calculate the local and global behavior of reinforced concrete columns under static-oriented pushover and cyclic loading. The proposed simulation method is validated by the results of tests carried out on the full-scale reinforced concrete columns. The application of the “Components Effects Combination Method” is compared with the proposed “Simultaneous Direct Method” (SDM). The obtained results show the necessity of applying SDM for nonlinear calculations. Especially, during the post-elastic phase, which occurs frequently during earthquake loading.

Coupled vibrations may occur between ship lift structure and the ship chamber during seismic process due to the ship chamber being hung at the roof of the ship lift. An investigation is carried out to explore the possibility of using different devices to connect the ship lift towers and the ship chamber to prevent the coupled vibrations. A three-dimensional shell finite element model is established, and then simplified into a three-dimensional truss finite element model through dynamic equivalent principle. And the numerical model of coupled vibration analysis is formed through static condensation, calculating the coupled vibration response between the ship lift structure and the ship chamber under five connection conditions: no connection, rigid connection, spring, viscous liquid damper and magneto-rheological fluid damper. The result shows that no connection and rigid connection between them are both inadvisable; the magneto-rheological fluid damper provides better vibration damping effect if suitable semi-active control strategy is applied, in comparison with passive control devices.

Resource allocation project scheduling problem (RCPSP) has been one of the challenging subjects amongst researchers in the past decades. Most of the researchers in this area have used deterministic variables; however, in a real project, activities are exposed to risks and uncertainties that cause delay in project’s duration. There are some researchers that have considered the risks for scheduling; however, new metahuristics are available to solve this problem for finding better solution with less computational time. In this paper, two new metahuristic algorithms are applied for solving fuzzy resource allocation project scheduling problem (FRCPSP), known as charged system search (CSS) and colliding body optimization (CBO). The results show that both of these algorithms find reasonable solutions; however, CBO finds the results in a less computational time, with a better quality. A case study is conducted to evaluate the performance and applicability of the proposed algorithms.

This study focused on the design of heat-resistant asphalt mixture for permafrost regions. Vermiculite powder with low thermal conductivity was used to replace some of the fine aggregates in the asphalt mixture to lower the thermal conductivity of asphalt mixture. Asphalt mixtures with different mass ratios (0, 3, 6, 9 and 12 %) of vermiculite powder were prepared for performance evaluation and thermal property evaluation. Wheel tracking test, low-temperature bending beam test, freeze–thaw splitting test and fatigue test were conducted to evaluate the influences of vermiculite powder on the high-temperature rutting resistance, low-temperature cracking resistance, moisture stability and anti-fatigue performance of asphalt mixture. Mathis TCI analyzer was used to analyze the influences of vermiculite powder on the thermal conductivity of asphalt mixture. Temperature monitor system was used to figure out the influences of vermiculite powder on the inside temperature of asphalt mixture. It is proved that vermiculite powder has no significant influences on the performances of asphalt mixture, while it obviously affects the thermal property of asphalt mixture. By the addition of 9–12 % vermiculite powder in asphalt mixture, the performances of asphalt mixture can still well meet the performance requirements for permafrost regions; the thermal conductivity can be reduced by 40–55 %; and the inside temperature of asphalt mixture can be lowered by 1–2 °C. It proves the feasibility of using vermiculite powder to produce heat-resistant asphalt mixture for permafrost regions.