This paper concludes that 4D models are a useful alternative to project scheduling tools like CPM networks and bar charts. They enable more people to understand a schedule quickly and identify potential problems. By developing a 4D model for a commercial construction project, we were able to detect the incompleteness of the original schedule, find inconsistencies in the level of detail among the schedule activities, and discover an impossible schedule sequence. We were also able to anticipate potential time-space conflicts and accessibility problems. The results of the case study show that 4D models are effective in evaluating the executability of a construction schedule. The case study also highlighted the need for improvements to 4D tools. 4D tools should include bar charts, component lists, and annotation tools in their graphical user interface. Automating schedule data preparation and 4D model generation in the design stages of a project can expedite 4D model development and use. Users need to be able to generate 4D models at multiple levels of detail and generate and evaluate alternative scenarios rapidly.

Closure of "Feasibility Study of 4D CAD in Commercial Construction"

Properties of fresh and hardened concrete

Construction simulation is the science of developing and experimenting with computer-based representations of construction systems to understand their underlying behavior. This branch of operations research applications in construction management has experienced significant academic growth over the past two decades. In this paper, the author summarizes his views on this topic as per his Peurifoy address, given in October 2008. The paper provides an overview of advancements in construction simulation theory as reported in literature. It then summarizes the key factors that contribute to successful deployment of simulation in the construction industry, and the key attributes of problems that make them more amenable for simulation modeling as opposed to other tools. The paper then provides an overview of long-term simulation initiatives leading to the next generation of computer modeling systems for construction, where simulation plays an integral role in a futuristic vision of automated project planning and control.

Role of Simulation in Construction Engineering and Management

The Semantic Web 10

SynOptics Communications Inc.

Chloride-induced corrosion is the main factor in determining the durability and service life of the reinforced concrete structures exposed to marine environments. Recognition of chloride diffusion phenomenon in concrete and developing a prediction model that can estimate the service life of the concrete structures subject to long-term exposure is vital for aggressive marine environments. The present study focuses on developing such a prediction model of chloride diffusion coefficient for silica fume concrete under long-term exposure to a durability site located in the southern region of Iran. All investigations are based on 16 concrete mix designs containing silica fume with variable water-to-binder ratios exposed to sea water for maximum period of 60 months. This empirical model is developed by applying regression analysis based on Fick’s second law on the experimental results and is compared with previous studies in this area. This comparison indicates that the predicted chloride diffusion coefficient level is within a ±25% error margin in the specimens. The results indicate that reducing the water-to-binder ratio and adding the silica fume to a dosage of 10% reduces the chloride diffusion coefficient in concrete. This study also confirms that the chloride diffusion coefficient increases with temperature and decreases over time.

Prediction of long-term chloride diffusion in silica fume concrete in a marine environment

A methodology for mobile crane lift path checking in heavy industrial projects

Modular construction is a common practice for building industrial plants, particularly in the oil sands region of Alberta, Canada. Each module is a project with its own activities and const...

Simulation-Based Multiagent Approach for Scheduling Modular Construction

Automated Crane Planning and Optimization for modular construction

At present, industrial projects are constructed primarily using a prefabricated approach. The modules are produced in an off-site facility and transported on transport trailers to the construction site where they are lifted by mobile cranes. One of the keys to the success of modular industrial projects is efficient crane planning, which includes path checking to find whether or not a crane has a feasible path through which to lift a module over obstructions in a congested plant. However, due to the large number of lifts, the manual path-checking practice is quite tedious and prone to error. In light of this problem, this paper proposes a methodology for automatically checking the lift paths for industrial projects. The proposed methodology simplifies and represents the three-dimensional site layout using project elevations. For each elevation, the crane feasible operation range (CFOR) is calculated based on the crane’s capacity and clearances, as well as site constraints. The pick area (PA) is cal...

Hosein Taghaddos

Papers

Prediction of long-term chloride diffusion in silica fume concrete in a marine environment

A methodology for mobile crane lift path checking in heavy industrial projects

Simulation-Based Multiagent Approach for Scheduling Modular Construction

Automated Crane Planning and Optimization for modular construction

Automated Method for Checking Crane Paths for Heavy Lifts in Industrial Projects