3 Problems with the Production Management Systems: Understanding the problem and the context
3.4 Information and Communication System Problems in Construction
3.4.1 Shortcomings of the current design and product modelling systems:
Construction drawings (2D) have been traditionally considered to be a language with which professionals within construction industry communicate. In the 1760s, a precise standardised method for representing three dimensional objects called descriptive geometry in two dimensions was developed by the Frenchman
Gaspard Monge (Koskela et al., 2010). The method was deemed so powerful that it was kept in secrecy for many years, and Monge published the details only in 1799 (Kant, 1799). Since then, descriptive geometry has been the basis for construction design drawings. Together with written description, such as bills of materials, drawings have been used to represent the object to be built, both for contractual purposes and for site execution (Koskela et al., 2010).
A number of Computer Aided Design (CAD) software have been developed over the years, which facilitate generation and distribution of drawings. However, due to the fragmentation prevalent in the construction industry, the ability to interpret these drawings on a project varies from one subcontractor to the other. Also, due to increasing complexity of building systems, drawings have become much difficult to interpret even for the technically competent. Computer Aided Design does not intrinsically support generation of intelligent design, whereas the objects contained within the drawings demonstrate behavioural patterns and where design objects can be controlled in a parametric way.
Current practice in using 2D CAD is that the designers and engineers develop solutions independent of each other. However, there is no potential solution to automatically check the design for consistency, and due to complexity of design, manual checking is quite difficult. This leads to design errors and inconsistencies, which are then identified on site and are costly to fix. Also, it is not possible to automate tasks such as fabrication using CNC systems using CAD drawings, or to check the design for potential clashes between various components such as building structure and facilities. It is also not possible to build fail-‐safe rules (design templates to ensure standard conformance) using 2D CAD systems.
On the contrary, object oriented design development, which is offered by Building Information Modelling software, is capable of representing intelligent behaviour and can integrate a multitude of information from various sources. (Eastman et al. 2008).
The problems with the traditional 2D CAD technologies during the construction project lifecycle are discussed below. The stages described below could be different in sequence depending on the type of the contractual agreement, for
example Design-‐Bid-‐Build or Design-‐Build. In Design-‐Build and partnership projects, some of the inefficiencies of the traditional process described below are taken care of, however, the critical inefficiencies related to the production phase most likely remain.
3.4.1.1 Problems during Pre-‐Construction
The key goal of the conceptual design stage is to capture the functional and aesthetic requirements from the client and translate that into design intent. This makes design a highly iterative process, where initially a significant amount of refinement is taking place and client input is being taken into account. The current paper based process leads to significant inefficiencies, as it is not easy to interpret and communicate the design intent about a three dimensional space in a two-‐ dimensional drawing (potentially for an untrained eye of the client). Also, through the paper-‐based process, critical project based information such as cost estimates and performance evaluation (such as energy, acoustics, structural, thermal, etc.) has to be carried out post design and manually. Often, when inefficiencies are found with the design, it is too late to make a change, which then leads to compromises with client’s original intentions.
3.4.1.2 Problems during Tendering and Bid Process
Traditional contracts based on the lowest bid, involve a strenuous bidding process, where contractors spend at least 1% of the estimated project costs on compiling bids (Eastman et al., 2011). These bids are developed using paper based or electronic 2D drawings, where manual extraction of quantities and interpretation of design is required. As a result, significant amount of time and effort is required in preparing the bid. If we consider a contractor’s hit rate as 20% (i.e. they win 1 job for every 5 bids), the 1% of bid development cost gets added to the overheads. Also, due to major inconsistencies in design, a significant amount of RFIs are generated even during the bid stages as the main contractor has to take input from their supply chain to arrive at a final cost.
3.4.1.3 Problems during Design and Detail
Developing a detailed design is a highly collaborative and iterative process, where a number of design consultants contribute towards the final design. The current 2D CAD and design processes do not lend themselves for collaborative design development. Most commonly an over-‐the-‐wall approach is taken towards design where each consultant (Architect, Structural, MEP, etc.) develops their respective design and passes it to the next as an input. This makes the process a very lengthy and costly. Also, due to the fragmented nature of design development, many issues related to physical clashes between different design elements (i.e. architectural and structural or structural and MEP etc.) remain undetected until the construction stage of the project. This leads to either rework or lengthy delays during the construction process.
A study carried out by Freire and Alarcón (2002) diagnosed and evaluated the traditional design process for three projects of a design consultant. The authors used lean principles to identify wastes present within the process and found the main wastes occurring within the process to be:
1. Ignorance of client requirements; 2. Bureaucracy and paper work; 3. Interdisciplinary coordination; 4. Information not available; and 5. Rework.
Freire and Alarcón (2002) also identified time distribution in traditional design process as shown in Table 3 below:
Table 3. Distribution of time in design tasks (Freire and Alarcón, 2002).
Category Duration (%) Designing 50.2 Verifying information 8.2 Collecting information 28.1 Correcting information 12.2 Issuing 1.4
The results from table above clearly show that the value adding activity of actual design work contributes to only 50.2% time spent on this overall process, where the rest constitute wasteful tasks.
3.4.1.4 Problems during Construction Phase
It is during the construction stage that the inefficiencies of the traditional design cause the biggest problems (Eastman et al., 2011, Kymmell, 2008).
• Rework due to inaccuracies or lack of detail: As the design is not normally checked for constructability and refined for execution, a thorough review takes place early in the project to identify errors and omissions.
• Lack of support for Prefabrication: Also, the lack of automation and parametric abilities of the 2D design makes is difficult to support a prefabrication strategy; hence most of the components have to be constructed on site, leading to inefficiencies.
• Clashes leading to rework: Two types of clashes could occur, physical clashes; i.e. construction elements clashing with each other as design hasn’t been refined or process clashes; where the work sequence hasn’t been properly planned due to lack of visualisation. This causes either a delay in work or complete rework of construction elements.
• Drawing Management: Drawing or design issue management becomes highly complex and inefficient in a 2D CAD/ paper based process. This leads to not only inefficiencies on construction projects, but also causes safety issues as probability of subcontractors working with a wrong revision of drawings increases. On a case study A a major accident happened where a subcontractor used an old revision of drawing to construct a concrete slab. This led to the failure of the slab and injury of two personnel. The subcontractor claimed that they had not received the latest copy of the drawing. Also, on an average it was found for company A that the expenses for postage and scanning of paper drawings were in the region of £200-‐ £300 (excluding personnel costs).
• Visualisation of design during planning: It is highly important that the production teams and project managers are familiar with the design and
complexity of tasks while planning and scheduling production tasks. However, with 2D drawings it becomes quite difficult to visualise 3D spaces and how the production will happen over a timeline, especially if it is a complex structure. Also, quite often it is realised during the project that required information from drawings and specifications is either missing or not clear. This leads to significant number of Requests for Information (RFIs) being sent to and from the project. It is widely documented that RFIs lead to major inefficiencies during a construction project.
3.4.1.5 Problems with Handover and Post Construction There are two important issues the project has to address:
• Handing over an accurate record and information about the facility to the owner
• Ensuring the information handed over supports effective operation and maintenance of the facility
Normally at the end of a project, all the as-‐built information is sorted and archived in boxes, which are then handed over to the client. However, as the information is mostly recorded on paper, this resource is hardly ever used or synchronized with a client’s facilities management system as demonstrated in the Maryland General Hospital case study, which was documented by the author (Eastman et al., 2011). The following observations were made in the case study:
• The lifecycle of the equipment was not optimized, i.e. the facitilities management system did not take into consideration issues such as maintenance intervals, servicing, etc.
• Warranty and other product-‐related information were not easily accessible. • No ready inventory of equipment was available.
The resulting processes are quite informal and dependent on knowledge gathered by experienced staff members about the facilities operations over the years. As a result, the hospital ends up spending considerable resources on Facilities Management but does not get the results it needs. The BIM-‐enabled process for recording and delivering as-‐built information offered an opportunity to record and
provide accurate as-‐built information, in a form, which helps maintain and manage the facilities in an efficient way and increase the lifecycle of the building.