Real Engineering Projects Research Articles

CAD-based Monte Carlo program for integrated simulation of nuclear system SuperMC

Monte Carlo (MC) method has distinct advantages to simulate complicated nuclear systems and is envisioned as a routine method for nuclear design and analysis in the future. High-fidelity simulation with MC method coupled with multi-physics phenomena simulation has significant impact on safety, economy and sustainability of nuclear systems. However, great challenges to current MC methods and codes prevent its application in real engineering projects. SuperMC, developed by the FDS Team in China, is a CAD-based Monte Carlo program for integrated simulation of nuclear systems by making use of hybrid MC and deterministic methods and advanced computer technologies. The design objective, architecture and main methodology of SuperMC are presented in this paper. SuperMC2.1, the latest version, can perform neutron, photon and coupled neutron and photon transport calculation, geometry and physics modeling, results and process visualization. It has been developed and verified by using a series of benchmarking cases such as the fusion reactor ITER model and the fast reactor BN-600 model. SuperMC is still in its evolution process toward a general and routine tool for the simulation of nuclear systems.

Prediction of structural vibrations using a coupled vehicle-track–building model

As a result of local factors, limited amounts of land and construction demands, subway lines are sometimes designed to run in close proximity to buildings. Hence, using a real Beijing subway engineering project, we have studied the vibration induced in a building by a moving rail vehicle. A numerical model of the spatially coupled vehicle–track–building system was developed to predict the vibration levels in the structure. The modeling theory was verified by comparison with multi-body system simulations and field test results. Two common types of track, namely, ballasted track and floating slab track were studied and their vibration-mitigation effects were compared in the time and frequency domains. A comparison of the particle peak velocities with the structural vibration limits of the floating floor slab and the first floor of a building revealed a very low possibility of severe damage resulting from vehicle-induced vibration for both types of tracks. We also conducted a one-third octave analysis of the vibration of each building floor and obtained the weighted root-mean-squared acceleration and vibration levels. A comparison of the weighted accelerations with the vibration limits for vibration perception by a human for both types of tracks also revealed that train-induced vibration had no obvious effect on daily human activities on most of the floors. The main exception to this observation was the first floor, which is located close to the vibration source. It is recommended that the first floor should be used for purposes other than residential. Furthermore, a comparison of the vibration levels of each floor for both types of tracks showed that the ballasted track had a better vibration-mitigation effect than the floating slab track for this special engineering case.

Towards phronetic knowledge for strategic planning in corporate real estate management

Purpose– The objective of this paper is to provide insights about the potential of real option thinking for corporate real estate management (CREM) from the owner-user perspective. A promising approach to classifying and evaluating flexibility in real estate is the real options approach. Most literature on real options look from an investor perspective.Design/methodology/approach– First, a review on real option thinking in the real estate and large engineering projects literature is provided using Flyvbjerg’s (2001) typology of knowledge systems. Next, the effects of exercising real options for various stakeholders in CREM is analysed in two case studies.Findings– The literature review shows that little research has been done on conditions and values needed to make real options applicable in the CREM practice of the owner-user of real estate. The case studies show that real options are more valuable to one stakeholder than to another.Practical implications– Based on the knowledge on conditions for and the consequences of exercising real options for various stakeholders, insight can be gained into the applicability of real options to the owner-user of real estate and how real options reasoning fits within this practice. A phronetic type of knowledge is needed that incorporates stakeholders’ interests.Originality/value– Creating phronetic knowledge would allow understanding why and how real options are used, or could be used in the future, and heuristics could be developed. In this way, real estate management should become more resilient to changes.

Integrated ANN-HMH Approach for Nonlinear Time-Cost Tradeoff Problem

AbstractThis paper presents an integrated Artificial Neural Network - Hybrid Meta Heuristic(ANN-HMH) method to solve the nonlinear time-cost tradeoff(TCT) problem of real life engineering projects. ANN models help to capture the existing nonlinear time-cost relationship in project activities. ANN models are then integrated with HMH technique to search for optimal TCT profile. HMH is a proven evolutionary multiobjective optimization technique for solving TCT problems. The study has implication in real time monitoring and control of project scheduling processes.

A Project-Based Approach to Teaching Programmable Logic Controller Course

Sequential control using ladder logic, Programmable Logic Controllers (PLCs), and operator interfaces are commonly used in the manufacturing industry today. The introduction course of programmable logic controller is a course that needs a lot of practice. We present a project-based approach to teaching it by introducing real engineering projects into the process of theory teaching. The students show more enthusiastic during learning course and their abilities of solving engineering problems are greatly enhanced.

A Hands-On Education Project: Antenna Design for Inter-CubeSat Communications [Education Column

CubeSat platforms have become a de facto standard for universities willing to initiate space-technology activities with students. These small satellite platforms ease the implementation of hands-on education projects and opening the apertures of new research areas. Moreover, due to the limited volume (a 10 cm cube) and power (1 W), the application of imaginative solutions is mandatory. This leads to new innovation processes in the course of CubeSat projects. In this paper, we present a hands-on education project the aim of which is the specification, design, building and measurement of an antenna for communication between nanosatellites and, in particular, CubeSats. The project lies within the framework of ETSIT-UPM innovative education activities in the area of space technology, where students play a leading role in real engineering projects.

Network theory-based analysis of risk interactions in large engineering projects

This paper presents an approach based on network theory to deal with risk interactions in large engineering projects. Indeed, such projects are exposed to numerous and interdependent risks of various nature, which makes their management more difficult. In this paper, a topological analysis based on network theory is presented, which aims at identifying key elements in the structure of interrelated risks potentially affecting a large engineering project. This analysis serves as a powerful complement to classical project risk analysis. Its originality lies in the application of some network theory indicators to the project risk management field. The construction of the risk network requires the involvement of the project manager and other team members assigned to the risk management process. Its interpretation improves their understanding of risks and their potential interactions. The outcomes of the analysis provide a support for decision-making regarding project risk management. An example of application to a real large engineering project is presented. The conclusion is that some new insights can be found about risks, about their interactions and about the global potential behavior of the project.

Durability problems of lining structures for Xiamen Xiang’an subsea tunnel in China

Durability problem of reinforced concrete for underground structures is a hot issue in the field of structural engineering. For underground structures, the prediction of structural service life and methodology for durability design are needed to estimate structural durability. Taking the case of Xiamen Xiang’an subsea tunnel as background, which is designed to meet the requirement of 100-year service life, the influential factors on tunnel lining durability are analyzed. Under the criteria of crack controlling and bearing capacity of lining structures, the theoretical service life of Xiamen Xiang’an subsea tunnel lining is studied. The regulations, which are needed for the diffusion capability of chloride ions in concrete by the relevant diffusion tests, are proposed. After a quick corrosion test, the bearing capacity test on eccentric short columns is implemented to investigate the variation rules in the bearing capacity of models with time. Influence of the corrosion degree of steel bars on the bearing capacity of models is also investigated. Based on the results of model tests, the acceleration ratio between the quick corrosion in laboratory test and the natural corrosion environments is established. Thus, the natural service life of subsea tunnel lining structures can be obtained by means of laboratory tests. Then, the proposed method using this modified model is employed to predict the service life of tunnel lining structures. Finally, the design and construction measures for improving the durability of lining structures of subsea tunnel are introduced. The proposed method in the present study based on a real engineering project is superior to those with only theoretical assumptions, and would be more suitable forsimilar projects.

Circular Inclined Concrete-Filled Steel Tubular Stub Columns Subjected to Axial Compression

In order to find out the mechanics behaviors of the inclined CFST stub columns which are used in some real engineering projects, a series of tests are performed and a total of 6 specimens with circular section were experimented. The main parameters were the inclined angle (0 degree and 9 degree) and with or without infilling concrete. Comparisons between measured sectional strengths and predicted sectional strengths using the existing codes were made. The results show that the circular inclined CFST stub columns behaved in a ductile manner and all the codes were conservative and available for predicting the capacities of the specimens.

Experimental Investigation on Rectangular Inclined Concrete-Filled Steel Tubular Stub Columns

In recent 10 years, inclined concrete-filled steel tubular (CFST) columns are applied for some real engineering projects in China. And so a total of 10 specimens were experimented to study the behaviors of the rectangular inclined CFST stub columns. The main parameters were the inclined angle (0 degree and 9 degree), the inclined orientation (major axis and minor axis) and with or without infilling concrete. Comparisons with predicted sectional strengths were made using the existing codes. The results clearly show that all the codes were conservative and available for predicting the capacities of the specimens.

The Fehleranalyse Error Analysis of Fully Characteristic Curve of Pump to Be Nominalization and Study for the Influence on Result of Hydraulic Transients Calculation

In this paper，by transforming the fully characteristic curve of pump with eighty specific speed to be numeralization he obtained fehleranalyse error of discrete data were analyzed based on the pump similarity theory and the difference between certain assumed condition and real situation in numeralization process. Then the influence of the fehleranalyse error of numeralization method on the pressure boost caused by Pump-off water hammer was computed by a Pump-off water hammer calculation within an real engineering project. The reliability of numeric calculation method of fully characteristic curve of Pump is proved.

Study on Crack Causes and Strengthening Measures of Large Span PC Continuous Box Girder Bridges

This template Based on cracks observation and finite element analysis of real engineering projects as well as bridge load test after reinforcement, causes and types of cracks in prestressed concrete box girder bridges and treating measurements are systematically studied. The results obtained from the calculation are presented to demonstrate the effect of sensitive factors, such as arrangement of longitudinal prestressed tendons, the magnitude of vertical prestressed force, temperature gradient, etc. The results show that the arrangement of longitudinal prestressed tendons and the magnitude of vertical prestressed force take key roles in cracks control of box girder webs. Lots of treating measurements are presented in accordance with different types of cracks, some of them are applied to a reinforcement engineering of a long span pretressed concrete continuous box girder bridge with cracks. Load test after reinforcement of the bridge demonstrates the reasonability of the treating measurements. Several design recommendations and construction measures about reinforcements and some sensitive factors mentioned above are proposed to control cracks.

Multi‐response robust screening in quality construction blue‐printing

PurposeThe aim of this paper is to circumvent the multi‐distribution effects and small sample constraints that may arise in unreplicated‐saturated fractional factorial designs during construction blueprint screening.Design/methodology/approachA simple additive ranking scheme is devised based on converting the responses of interest to rank variables regardless of the nature of each response and the optimization direction that may be issued for each of them. Collapsing all ranked responses to a single rank response, appropriately referred to as “Super‐Ranking”, allows simultaneous optimization for all factor settings considered.Research limitations/implicationsThe Super‐Rank response is treated by Wilcoxon's rank sum test or Mann‐Whitney's test, aiming to establish possible factor‐setting differences by exploring their statistical significance. An optimal value for each response is predicted.Practical implicationsIt is stressed, by example, that the model may handle simultaneously any number of quality characteristics. A case study based on a real geotechnical engineering project is used to illustrate how this method may be applied for optimizing simultaneously three quality characteristics that belong to each of the three possible cases, i.e. “nominal‐is‐best”, “larger‐is‐better”, and “smaller‐is‐better” respectively. For this reason, a screening set of experiments is performed on a professional CAD/CAE software package making use of an L8(27) orthogonal array where all seven factor columns are saturated by group excavation controls.Originality/valueThe statistical nature of this method is discussed in comparison with results produced by the desirability method for the case of exhausted degrees of freedom for the error. The case study itself is a unique paradigm from the area of construction operations management.

Determination of rock resistant coefficient based on Mohr-Coulomb criterion for underwater tunnel

According to the load-structure method, the wall rock with lining can bear the load caused by the surrounding rock, and the rock resistant coefficient (RRC) is a key parameter for evaluating the capacity of this wall rock. Based on the Mohr-Coulomb yield criterion, this paper develops a formula for calculating the RRC, which has been applied to the real engineering project, such as Xiamen Xiang’an East Passage Underwater Tunnel Project. The fact shows that this formula is helpful for designers to determine the RRC value.

Real Options and Real Engineering Projects

:Real options analysis is a tool that has not fully justified itself in the face of real world complexity. It is intended to value flexibility in future choices; however, much of the literature focuses on the mathematical details of how to perform real options analyses, without taking the time to ask whether key characteristics of engineering projects have been properly recognized. In addition, many papers contrast real options analysis with a simple NPV analysis with deterministic data and no options. Because engineering economic analysis has long included decision trees, sensitivity analysis, simulation and other tools, the key question is, what does real options analysis add to this toolbox? A comparison of real and financial options and case studies of engineering projects led us to conclude that the value of real options is more limited than many suggest. Different recommendations due to the use of real options may be limited to near-zero NPV projects where the future benefit stream can be well forecasted and where uncertainty can be identified. This can lead to great difficulty in applying options to real engineering projects.

Finite element modeling of underground water flow with Ranney wells

The objectives of this study were to define the regional and local groundwater flow, and to give quantitative estimates of the groundwater dynamic parameters and of the available groundwater resources. To achieve these objectives, numerical tools are required to quantitatively model flow through porous saturated and unsaturated media. We have developed a general finite element (FE) model for underground water flow and specific algorithms for Ranney wells. Solutions for steady and unsteady conditions are obtained by using two basic models: global and local. The global model consists of 3D finite elements and 1D finite elements with the equivalent well permeability representing Ranney wells. The local models are generated around wells, using solutions for all quantities from 3D global model at a cylindrical surface which bounds the local model. The local model consists of a fine 3D FE mesh and 1D elements used to model each of the well screens. We developed a software for pre- and post-processing, Lizza, which can be used for easy modeling of complex engineering underground water flow problems with Ranney wells. The FE package PAK-P is used as the solver. This software can handle flow regions with general irregular boundaries. The flow region itself may be composed of layers of nonuniform soils having an arbitrary degree of local anisotropy. Flow can occur in the vertical plane, the horizontal plane, or in a three dimensional region exhibiting radial symmetry about the vertical axis. The water flow model includes constant or time-varying prescribed head and flux boundaries, as well as boundaries controlled by atmospheric conditions. At a soil surface, boundary conditions may change during the time evolution from prescribed flux to prescribed head type conditions (and vice versa). The model also include a seepage face boundary through which water leaves the saturated part of the flow domain, and free drainage boundary conditions. The results of modeling several real engineering projects (Belgrade Water Supply Center) are presented.

Generalized relationship for determining soil electrical resistivity from its thermal resistivity

The knowledge of soil electrical and thermal resistivity finds its application in many of the real life engineering projects like laying of high voltage buried power cables, ground modification techniques etc. This necessitates determination of soil electrical resistivity and thermal resistivity and development of a relationship between them. However, as these resistivities mainly depend on the type of the soil (i.e. its physical composition) and its saturation, efforts have been made in this paper, to develop a generalized relationship to relate them. Validation of the relationship has been conducted vis-à-vis the results obtained from the laboratory experiments and those reported in literature.

99/01257 Analysis and control of Yimin-Fengtun 500 kV TCSC system : Zhou, X. et al. Electric Power Systems Research, 1998, 46, (3), 157–168

The Yimin-Fengtun thyristor controlled series compensation (TCSC) system that is under research will be situated at a main corridor of 500 kV transmission system of northeast China. The TCSC will be used to increase the transient stability and dynamic stability of the power system. In order to adapt to the development of the transmission system, the design for the controller must meet the requirements of systemization and robustness. The TCSC project will be the first FACTS (flexible ac transmission systems) project installed in the main grid of China. In this paper, based on the real engineering project, systematic research is done on the models of the TCSC, the control algorithms, the development of simulation software and the implementation of the TCSC. Some achievements have been obtained on the studies of engineering applications, control schemes, electromagnetic transient models and electromechanical transient models of the TCSC and software development as well.

A knowledge-based system for identifying potential project risks

This paper presents an integrated knowledge-based system (KBS) that assists project managers in identifying potential risk factors and the corresponding project risks. The knowledge acquired from previous experience is captured by the proposed project risk identification model which incorporates the work breakdown structure (WBS). The knowledge is then translated into rules for the KBS. A prototype was developed based on the proposed KBS to determine potential risk factors along with their risk effects and the related work packages for an extra high-voltage (EHV) transmission line construction project. The results obtained clearly demonstrate the feasibility and the applicability of this system in a real engineering project environment.

Analysis and control of Yimin–Fengtun 500 kV TCSC system

The Yimin–Fengtun thyristor controlled series compensation (TCSC) system that is under research will be situated at a main corridor of 500 kV transmission system of northeast China. The TCSC will be used to increase the transient stability and dynamic stability of the power system. In order to adapt to the development of the transmission system, the design for the controller must meet the requirements of systemization and robustness. The TCSC project will be the first FACTS (flexible ac transmission systems) project installed in the main grid of China. In this paper, based on the real engineering project, systematic research is done on the models of the TCSC, the control algorithms, the development of simulation software and the implementation of the TCSC. Some achievements have been obtained on the studies of engineering applications, control schemes, electromagnetic transient models and electromechanical transient models of the TCSC and software development as well.