The construction industry has significantly evolved and nowadays actively exploits the newest technologies for improving performance and reducing time, costs, the involvement of the workforce in the process and minimising defects. Prefabrication and simulation have become perfect tools for reaching these strategic objectives and bringing up positive shifts in the whole industry.
Nowadays, in the age of widespread modular construction, the issue of becoming more time- and cost-effective has become extremely acute for constructors. One of the tools that can assist in improving the overall performance of the construction industry is the visualisation of projects. Its necessity can be easily explained by the fact that most managers rely on intuition and imagination when making decisions regarding planning and scheduling.
In means that in the case if it is possible to visualise the project, it is generally easier to organise the flow of the working process. Except for this primary benefit, this tool also has other advantages such as helping the site manager in bettering the perception of the project because one of the visualisation options is displaying virtual environment of the project; minimizing the risks of failing to meet deadlines.
After all, it optimises the schedule at every stage of construction; enhancing communication among managers and making it more efficient as they see the actual picture, not the one drawn by their imagination; and allowing to find construction alternatives that can be applied during every particular stage if they prove to be more effective. In addition to it, a visualisation is a perfect tool for avoiding defects or, at least, minimizing their quantity because it makes it possible to see the simulation of the construction in a that helps assess the existence of defects and eradicate them (Murray, Fernando & Aouad 2004).
The specificity of the visualisation tool is that it consists of four primary components that altogether increase the productivity of the construction process. It includes the virtual environment a tool allowing the user to analyse the elements of the constructions (modules) within the environment they will be installed in, thus creating a simulation of the projects. Additionally, it has the function of automatic constraint recognition that assists in assembling and disassembling the parts of the edifice to see whether they collide once put together.
The next constituent is the construction database that stores all information about the project including all changes in building, the order of construction, deliveries, and stock of sites. Finally, there is a system responsible for the functioning of the visualisation tool, a task manager, which provides the user with the information necessary to make the operation smooth and flawless such as the description of the data that should be entered or the steps needed for creating a simulation model.
Visualisation is indissolubly related to the process of simulation. It is one of its variations. Simulation is actively used for creating a virtual environment, developing and altering the schedule of construction, and framing the building design. As of creating a virtual environment, simulation helps in generating a 3D picture of the edifice under construction. The building design is necessary for viewing the modular parts of the construction and putting them together to view the result of the project. What should be noted that using graphic tools for simulation makes it possible to rotate the objects or assemble them in the program so that it is possible to eliminate defects because the project can be analysed before being brought to life? As of schedule, it can be modified and altered by using the simulation tool because every time the new object is added to the system, the schedule automatically changes, so that it helps improve the time performance of the constructors (Murray, Fernando & Aouad 2004).
What is also significant about simulation is that is has a wide range of advantages for architecture engineering and construction (AEC), especially if compared with conventional methods of planning and scheduling. This tool is dynamic that means that it is easy to change it every time a new resource or modular part is added to the database. Because of its dynamism, computer-aided simulation easily incorporates many random factors such as weather conditions or the status or the working team or operation of the equipment used in the construction process.
Finally, it is useful in modelling resources, e.g. demonstrating the relationship between the stage of the construction and the resources used or the simultaneous use of one resource in different processes, etc. Altogether, they make simulation a comprehensive and one of the most efficient tools for integrating design and construction (Shi 1999). Moreover, it focuses on the prioritisation of tasks, so that it is a perfect way for optimizing the flow of the working process (Hasan, Al-Hussein & Gillis 2010).
Furthermore, there is a way to exploit simulation for assessing productivity and increasing it. This process can be somewhat complicated because it is impossible to predict some random factors including weather conditions such as extreme temperatures, wind or rain or the operational status of the equipment used and breakdowns or emergencies that can have the negative influence on the level of productivity, but, in general, simulation helps in analysing it. Several factors are taken into consideration while estimating potential productivity and developing the overall schedule for the project. In most cases, they include time needed for production, transportation, and putting the needed modular part in place as well as the distance between the factory and assembly yard and the location of resources, factories, and the future building (. 2013). These factors if evaluated appropriately while designing the simulation model can help spectacularly improve productivity.
Except for the benefits mentioned above, there is one more significant argument in favour of using it. It is not a secret that construction is a magnificent contributor to the issue of natural environment pollution. As most industries become more environmentally friendly and there are growing concerns regarding climate change, the construction industry cannot but follow the overall tendency of trying to reduce the negative impact on the environment. Simulation can become another effective tool for reducing the influence of the construction process on the environment, especially decreasing the emission of CO2 in the atmosphere.
The tool can be used for assessing the number of cranes that will be used for assembling the edifice and their type single- or double-jibbed. The reason why simulation is an effective tool for reaching this goal is that it considers numerous dimensions of the projects such as source and destination locations, weight and size of modular parts, the speed of lifting modules, etc. Moreover, it examines the productivity of the cranes including the amount of energy consumed. That said, it was found that double-jibbed cranes are more productive and environmentally friendly than single-jibbed. They consume less fuel that is why they produce less CO2 emissions (Hasan et al. 2013).
At the same time, double-jibbed cranes are more productive because they are less time-consuming when it comes to hooking modules and lifting them. In addition to it, they are more cost-effective because even though their rental cost is higher, the number of cranes needed for the project and the number of workers involved are lower. So, the result of the simulation model with time, costs, fuel consumption, and cranes productivity as the inputs, is that it is better to rather than single-jibbed because they make the construction process cheaper and quicker (Hasan, Al-Hussein & Gillis 2010).
Even though simulation has proved to be an effective tool for improving construction performance and has numerous advantages, some steps should be taken while developing the simulation model so that it produces the correct results. First, it is necessary to apply proper input data to the model. It means that it should be introduced and analysed in an appropriate statistical form. Moreover, it is vital to remember that no important factors can be ignored. For example, in the case of using simulation for modular construction projects, it is important to assess the average time for design, prefabrication and assembling, distances between the factory and the assembly yard, potential delays in delivery, etc. Second, it is crucial to analyse the outputs of the simulation model. In the case of construction, it means that what is assessed is whether the outputs of the model comply with the plan for construction. This step can involve the estimation of any vital factor such as time, costs, workforce involved, etc.
The final condition is the validation of the simulation model. There are various ways to do it, but one used for construction is comparing the results with historical or published data such as the results of the simulation model developed earlier by the particular constructor or those of similar projects. What should be noted is that a similar project does not necessarily mean erecting separate edifice, it can as well be related to building one floor or installing one door. The reason for choosing this specific way for validating the model is that construction is a cyclic process, so it does not evolve significantly and always involves similar inputs and has similar outcomes.
That said, if the results of the model correspond to the result of the models that proved to be successful, then it can be used in the construction process (AbouRizk & Halpin 1990). What also should be highlighted is that because it is recommended to validate the results of the model using the previous projects that were cyclic, such simulation is referred to as simulation of repetitive construction processes.
Nowadays, the construction industry witnesses the new tendency towards the automation of the processes such as design, prefabrication, construction, simulation, and planning. What is most significant about automation is that it implies the use of computers at every stage of construction. For example, when speaking about design, automation means exploiting a wide range of graphic technologies including 3D and 4D that make the whole construction process easier and less time-consuming.
They are used for creating the design of the future construction from separate modular parts added to the database of the computer program and estimating it within the environment it will be put in. Automation of prefabrication implies the use of robotics and assembly lines in manufacturing modular parts. Furthermore, robots and machines are used in assembling and construction. In general, the primary aim of automation is reducing the involvement of workers in the construction process that will entail the decrease in costs and time and the increase of safety in the working place.
However, introducing robotics to prefabrication and construction faces numerous barriers both economic and technological. Except for the fact that the transition to automation and robotisation is costly and requires implementing many changes in the construction process, it also needs the development of new systems that would comply with the use of robots such as mobile platform and necessary software for control and management (Neelamkavil 1999).
As of the automation of simulation, it comes down to creating the virtual environment and building design. What can be added to the in the paper is that automation makes real-time construction process simulation possible. It means that every step of the construction process will be automatically displayed in a computer program that will be useful for planning and control. The same can be said about the automation of the scheduling process. In addition to it, automation helps save time because there is no need to develop a new simulation model or change the schedule manually every time a new factor emerges. After all, it changes automatically. The only thing that should be done is adding a new factor to the database, and the computer does all the necessary calculation showing the necessary alterations to the schedule. Moreover, the data is collected in the real-time mode, so, every time a new step is taken or a new modular part is put in its place, the schedule changes.
What in general can be said about automation is that once the technological and economic barriers are overcome and the process becomes flawless, it will turn into the source of limitless advantages because it will help optimise and control the construction process. Moreover, all documentation on the project will be well organised, accurate, and timely. The status of every stage of the construction project will be up-to-date and easily accessible. What is most vital is the fact that automation will inevitably lead to the minimum defects and the maximum performance not to mention the reduction of costs and emissions of greenhouse gases into the atmosphere making the construction industry time-, cost-, and energy-effective.
In conclusion, it may be highlighted once again that today the primary strategic objective of the construction industry is becoming more productive and environmentally friendly and, at the same time, less time- and cost-consuming. To achieve this goal, the constructors exploit a wide range of methods including developing simulation models and automation of the whole process of construction. Initially, these tools require time, money, and a lot of skills and knowledge and face many barriers, but once they are fully implemented in the process, they guarantee that it is flawless and become a source of numerous benefits.