BIM-based automated design and planning for boarding of light-frame residential buildings

Highlights

• Improper boarding design and planning leads to a significant amount of material waste.

• A rule-based automated BIM approach to boarding design and planning is proposed.

• Rule-based design algorithms are developed to automate the boarding design.

• Design rules are comprehensively formalised based on trades' know-how.

• A prototype system is developed as an Autodesk Revit add-on tool for demonstration.

Abstract

Building information modelling technology provides a game-changing solution to address the challenges encountered in the AEC industry. However, this technology currently is not sufficient to fulfil the needs of construction practitioners in terms of proactive design and planning for boarding of light-frame residential buildings. This is partially due to the fact that boarding design and planning requires trades' know-how and substantial manual effort in developing the building information models. Current manual and ad hoc decision making for boarding of light-frame buildings leads to the generation of a significant amount of material waste. This research thus proposes a rule-based automated building information model (BIM) approach for designing boarding layout and planning material sheet cutting, resulting in practically feasible solutions with minimal material waste. In this research, object-based computer-processable layout design rules are comprehensively formalised based on trades' know-how. On this basis, rule-based design algorithms are further developed and integrated with mathematical algorithms in order to automatically generate design and planning alternatives while minimising material waste. Rich information in the BIM is leveraged to automate the rule-based boarding design and planning. A prototype system is developed based on Autodesk Revit via Application Programming Interface. A typical wood-framed residential building is used as a case study to test the developed prototype system. The results show the proposed approach successfully preserves the know-how of senior trades people while also minimising material waste in automating the boarding design and planning.

Introduction

In North America, light-frame structures, such as light wood framing and light gauge steel framing systems, are widely used in residential buildings. Wall studs and floor joists in light-frame walls and floors need to be covered using sheathing and drywall sheets to form the exterior and interior sides. In general, sheets of sheathing and drywall are available in rectangular shapes with varying dimensions (e.g., 4′ × 8′, 4′ × 10′, and 4′ × 12′) and thicknesses (e.g., 1/2″ and 5/8″). In construction practice, boarding sheets of nominal sizes are cut to designed dimensions, then fastened to wood (or metal) studs and joists. Boarding design and planning herein refers to the layout design of sheathing and drywall sheets on walls and floors according to trades' know-how as well as the material cutting plan. Such “design and planning” differs from the general perception of engineering design such as structural design, and it is also distinguished from commonly practiced planning and scheduling on the project level –which is concerned about developing work breakdown structures and sequencing activities into a project network model for critical path scheduling analysis [22,23]. Boarding design and planning is carried out by trades either late in the design stage, after all architectural and structural designs have been finalised, or during the construction phase. It should be noted that architects primarily focus on architectural aspects such as energy and sound performances in determining the thickness and material of drywall sheets, while structural engineers concentrate on structural performances in deciding the layout patterns of sheathing sheets in structural components (e.g., shear walls). Inputs are required from construction practitioners (e.g., carpenters) to properly design the layout of boarding sheets according to practical know-how and design principles, and to plan material cutting and installation. However, in current practice, proactive boarding design and planning is largely overlooked due to the fact that it requires [1] construction-centric design knowledge that is not accommodated in the existing design software and [2] substantial effort on the part of the construction engineer working in the field to add relevant information in the building design models. In most cases, construction practitioners make their ad hoc decisions regarding the boarding layout and the cutting plan of material sheets solely based on experience and rules of thumb. Such an experience-based, ad hoc approach to decision making often results in considerable material waste and rework in the field. According to the National Association of Home Builders [31], for instance, the construction of a typical 2000 ft² residential house can lead to as much as 8000 lb. of solid waste, of which approximately 2000 lb. is drywall. As such, there is a need for innovative technology which effectively enables proactive design and planning for boarding of light-frame buildings.

Building information modelling technology has the potential to revolutionize the construction industry. A building information model (BIM) is a purpose-built information model, as the level of detail (LoD) of the information in the BIM depends on the tasks for which it will be used [9]. In general, building objects in a given BIM can be modelled at various LoDs ranging from LoD 100 to LoD 500 [3]. With the increase in LoD, building information and design details are increasingly enriched in BIMs to represent the location, orientation, size, shape, quantity, and non-graphic information of the building [34]. To make a BIM fit for use by contractors and sub-contractors, it needs to be designed with sufficient construction details (i.e., construction-specific information) for specific application needs. In fact, building objects in a given BIM must be developed at LoD 350 or higher to represent detailed sub-components (e.g., blocking, wall bracing, boarding sheets, and so on) of building components [39]. Such detailed BIMs are of vital importance in project coordination and decision making in relation to construction material takeoff and planning applications during the construction stage [26]. Nevertheless, developing a construction-centric BIM through manual modelling is time-consuming and error-prone. Increasing the LoD from one level to another increases the modelling time by a significant margin (in the range of two to eleven times) [19]. As such, it is challenging for construction professionals, who play the crucial role in transforming designs into structures under tight time constraints in the field, to translate construction-specific data into BIMs. Generating BIMs in an efficient and cost-effective manner is identified by Ding et al. [8] as one of the primary challenges faced by the industry in implementing BIM in the construction field. For this reason, boarding design for light-frame residential housing (i.e., precise sheathing and drywall layout information) typically is not represented explicitly in BIMs. The resulting BIM is still far from sufficient to fulfil the specific needs of building trades.

To address these deficiencies, this research explores a novel rule-based automated BIM approach to boarding design and planning (i.e., designing sheathing and drywall layouts and planning sheet material cut). The original contribution is the novel rule-based design algorithms capable of generating various boarding layout design alternatives in BIM. Design rules are comprehensively formalised based on trades' know-how and are encoded into rule-based design algorithms to preserve trades know-how in the development of boarding design and planning. Established mathematical algorithms (i.e., greedy algorithms) are applied in connection with the proposed rule-based algorithms enabling an iterative process to evaluate various design alternatives and identify the “optimal” boarding design alternatives and material cutting plans with minimal material waste. Rich building information, including both geometric information and functional information of building components, are extracted from BIMs to facilitate the automated rule-based boarding design and planning.

The remainder of this paper is organised as follows. In Section 2, the literature pertaining to BIM-enabled construction design and planning, parametric modelling technology, and BIM-based material waste minimization is reviewed in order to clarify the point of departure and demonstrate the rationale underlying this research. Subsequently, the methodology for automated boarding design and planning is described in Section 3. Section 4 presents boarding design rules. The development of an automated design and planning system for boarding of light-frame buildings is described in Section 5. A case study of a wood-framed residential building is presented to validate the methodology and verify the prototype system in Section 6. The final section concludes by highlighting the research contribution of this paper.