# BIM for Construction Management/Introduction
## Introduction

The construction industry is a core industry in any economy since it provides the physical infrastructure that is fit for use by people. Construction can include the building, renovation, or demolition of ‘assets’ as diverse as houses, offices, dams, bridges, roads and factories [Refer to table 1]. Forecasts suggest that demand for infrastructure is increasing and trillions of dollars are to be invested in infrastructure in the coming decades. Additionally, billion-dollar-plus mega projects will account for a larger share of these developments. Despite the development of various approaches in construction management, the industry is still faced with stagnant productivity and low profit margins. In fact, the productivity (‘000$/worker) of the industry has remained stagnant for the last century while more than doubling in other industries such as manufacturing . The challenges the industry faces are best understood by understanding the nature of the construction industry.
| Buildings | Infrastructure | Industrial |
| Residential | Roads | Oil & Gas |
| Commercial | Railways | Power Stations |
| Administrative | Airports | Pipelines |
| Villas | Dams | |

## The nature of the construction sector

Each construction project is one of a kind forming a unique set of organizations, designs, processes, and objectives of its own. The construction process is complex, time-consuming and fragmented. The technological complexity ranges from simple, familiar, well-known materials, trades, and designs to highly complex facilities involving multiple interacting systems and other requirements dependent on the nature and objectives of the project. Regardless of a project’s technological complexity, any mid-to-large sized project also involves a high-level of organizational complexity. This is because any project has participants that have varying specialized skills that have useful contributions to the delivery of the project. These participants can be separated into five generic groups: builders, designers, regulators, purchasers and users of the ‘assets.' Each of these groups can then be further subdivided into specialist interest groups such that any project brings together a large number of participants with varying specialties. These interacting components that result in highly complex undertakings have resulted in an industry that seldom delivers projects on-time, within budget, and to specifications.

## Construction Management

Construction management concerns the management of construction projects and businesses to ensure that projects are delivered on-time, within-budget, to specifications, while meeting expected aesthetic, socially responsible and environmental impacts. This means that it covers the management of the construction process from its conception till hand-over in order to achieve economic success. It addresses the effective planning, organizing, application, coordination, monitoring, control and reporting of the core business processes of marketing, procurement, execution, administration, accounts and finance necessary to achieve economic success and/or profitability for an organization engaged in providing infrastructure.
A builder’s main objective, as we see it, is to achieve a laminar flow of work, i.e., an uninterrupted workflow of crews. A laminar flow is free of crew stoppages, interferences, idle hours, and is achievable when a planner develops a buildable schedule. Various approaches have been proposed in academic literature and adopted by contractors over the last decade. Those include: critical path method, lean construction management, advanced work packaging, modularization, and off-site fabrication, etc. We propose that comprehensive and reliable information are essential for the success of any of those methods.

## The role of information in construction management

Regardless of the specifics of any of these approaches, they all involve decisions, which are based on the current status of the project. Given the nature of the construction process, decisions are often taken by a group of participants who consider multiple criteria. Each participant forms an image of the current status of the project and vision of the future situation in his/her head based on his/her own interpretations of documents provided by the other participants. Typical documents include blueprints, design drawings, schedules, budget, procurement orders, equipment logs, and progress reports. These interpretations and information form the basis of the discussions and decisions about the appropriate design of the asset, when, how, and by whom it should be built, how long the whole project or a part of the project should take, and how much things will cost. As such, a large portion of the planning and coordination of the project occurs primarily in the participants’ heads and are not captured in any way. This has several effects:
* Information may be miscommunicated between parties (party forgets a piece of information, party misunderstands or misinterprets information)
* Different parties (owners & contractors) may work from different versions of reality which results in disagreements on matters such as construction progress, change orders and claims management
* Resulting actions and results are not consistent and repeatable from meeting to meeting and project to project
* Companies miss out on an opportunity to capture and analyze data in performance analytics which can lead to better outcomes and risk management.
Given that it may be difficult to imagine the amount of information and relationships, let us look into a common object we all know of: the column.

### A typical construction object: the column

In order for us to construct a column, there are many stages and scopes involved. This includes engineering (design), procurement (supply material), and construction (building). In order for the column to be built, various conditions have to be met. Those include completed design, material availability, prior activities completion, crew availability, engineers’ availability, and so on. Effectively, this means that for any given construction object in a project there are various disciplines, decisions, analysis, material, data, and documents involved (Refer to figure 1). Moreover, a revision or change in any of these attributes have to be accounted for and managed, in order to assess the change’s impact on other attributes. Therefore, it is apparent, that even for an object as basic as a column there are plenty of relationships, information, and complexities that have bearing on its successful delivery.
Given that even in the most basic of projects there will be hundreds of objects involved, imagine the amount of information and relationships that must be managed for its completion within time, on budget, and to specifications. This is even more challenging in medium to large sized projects, where there can be millions of objects of varying types that belong to several disciplines and require the involvement of higher number of participants. Ultimately, information mismanagement can result in delays in Engineering, out of sequence work, inconsistent progress, work disruption, scope creep, and hand over delay for instance. The challenge is further compounded by the fact that each construction project is one of a kind, forming a unique set of organizations, designs, processes and objectives of its own. This makes the task of information modelling and management more challenging as few inputs can be generalized, standardized, hardcoded and rendered applicable to the next project.

## Building Information Modeling (BIM)

At its core, BIM is an enabler. It enables better information flows, which enables better decision making, and consequently leads to better buildings and more effective delivery. In its broadest sense, BIM is the process of developing and managing a product model in a multi-disciplinary environment over the lifecycle of a project. It thus must be emphasized that we refer to BIM as Building Information Modelling rather than the Building Information model, and consequently advocate for BIM as an approach and a way of doing things. BIM ought to cover the building’s lifecycle – from inception through to demolition. The elegance and simplicity of BIM as a concept is best in the following definition:
“Building information modeling is an IT enabled approach that involves applying and maintain an integral digital representation of all building information for different phases of the project lifecycle in the form of a data repository.”(Pittard & Sell 2016)
However, despite the focus on technology, a BIM approach requires pre-requisites such as a change in the culture, procedures and roles compared to non-BIM based projects. Specifically, it requires a collaborative approach in project delivery, where different stakeholders both internal and external to a contractor act in cohesion. The combination of technology and collaborative work would improve the quality of the delivered product along with the reliability, timeliness, and consistency of the process to create and change information.
A building information model contains the geometrical properties of all construction objects, based on which standardized quantity surveying methods can be used to calculate quantities. In essence, it is a digital representation of the scope of the project, and can be linked to a multitude of functions such required resources, time to build, and the cost of building.
BIM, as such, acts as the primary information repository for the whole project team – both internal and external to the builder. This ensures that all designers, builders, and subcontractors maintain a common basis for both design and delivery, so that the relationships between conventionally isolated information pools may be fully explored and detailed. This is equally useful within the builder’s team, where all participants have access to the same information and BIM can be used to extract all the relevant information and reports: plans, schedules, material take offs, and so on. In that sense there are multiple dimensions to a BIM model that go beyond the 3D representation, commonly referred to as nD. In essence, BIM provides a common data environment to store all information that can be used to demonstrate entire asset lifecycle from construction through to operation.
For a contractor, BIM can then be leveraged to better understand, plan, and control costs and schedules by providing an environment where the right information can be made at the right time, to reduce requests for information, manage change, and limit (or even eliminate) unforeseen costs and delays.

### A BIM-based, Multi-tiered approach

As mentioned earlier, a contractor’s objective is to achieve a laminar flow of work in order to complete the project on-time, within-budget, and to-specs. A laminar flow is free of crew stoppages, interferences, idle hours, and is achievable when a planner develops a buildable schedule based on comprehensive and reliable information.
In order to do so, a robust pull-driven approach is necessary to optimize the supply chain. Take for instance an area where foundations have to be casted, and reinforcement cutting and bending has been subcontracted to another party. The subcontractor may sub-optimize and complete the heaviest bars first in order to increase his/her progress, neglecting the fact that the contractor will not be able to pour any of the foundations because the foundation’s rebar isn’t complete. Similarly, necessary documents such as the method statement need to be available for the builder to complete work when it was scheduled. As such, planning for all pre-requisites needs to happen with the end in mind (construction & hand-over) ie. A pull driven technique.
Such a pull driven technique is best served by a multi-tiered approach to planning. The tiers comprise a master schedule, N-month look-ahead schedule, and N-week look-ahead schedule—which correspond to a long-term, mid-term, and short-term schedule, respectively. The master schedule is built backward from construction and sets the milestones and targets for deliverables. N-month-look ahead is a verification tier to verify the build-ability of planned activities. Examples of verification information include the readiness of long-lead materials, crews, drawings, equipment and engineering. The third tier is the N-week look ahead schedule and is a confirmation tier. It confirms the build ability of the schedule and ensures coordination between different crews. Examples of confirmation include accessibility and availability of crews.
However, such an approach requires strategic early planning, a clear project structure, and an effective flow of information which depends on a disciplined set of procedures. Therefore, effective project control management systems are conducive to successful project management. Integrated databases and workflows, ideally based on BIM (3D CAD model) should support this approach as well as other functions.

### Defining Functions

The approach discussed above is dependent on various control functions being fulfilled. To begin with, the scope is defined. That is, in the case of our concrete object, the object is modelled and accordingly the concrete volume can be calculated. This is followed by the estimation stage, where the needed resources are identified and accordingly the unit price is set for the object. High level planning follows this, from which realistic targets are set for the completion dates of activities. Procurement of material is then driven by the construction due dates in order to ensure it is available at the right time. Site management and progress monitoring then ensure that all requirements are available in order to build, and monitor the progress accordingly. Finally, quality control ensures that the column is being constructed according to specifications to conclusively close out the workspace and prevent rework. An illustration of the output from each of these functions can be seen in figure 3. This is then followed with commissioning and handover of the object.

### The Project Data model
#### Key Map of Control Data Models

A project data model is a representation of data items and the relationships between them, all of which are modeled to resemble a real world project. The project data model groups the data items and the relationships into multiple sub-models (control data models) based on functionality. Hence a collection of data items and relationships makes up a control data model, and a collection of control data models makes up a project data model. The individual boxes in Figure 5—such as the Scope Model, the Progress Control Model, and the Quality Control Model—are examples of a control data model with a functional purpose. Each control data model contains hundreds of data item types, and the amount of information can easily grow by several orders of magnitude if different instances of the types and versions of the data models generated during the project are accounted for. Moreover, this data is not static and as such is continuously updated, and these updates must be captured and assessed.
The lines in Figure 5 represent the connections (relationships) between the control data models and the key data items used for the connections. For instance, the line between the Scope Model and the Estimation Model shows that a 3D object in the Scope Model connects (relates) to an estimate item in the Estimation Model. Figure 5 is a key map—a high-level diagram showing how information is organized based on functionality. Each control data model in it roughly relates to a chapter or two in the book.
Traditionally the data models in Figure 5 were deployed without the Scope Model, i.e., BIM. The noticeable difference in this book is that BIM is deployed and is playing a key role in integrating the information that used to be in silos in the project data model. All of the control models in Figure 5 are connected to the BIM, which shows that BIM is serving as the orchestrator of data flow between the different control data models and has the appropriate context to be the main interface for team members to input, retrieve, and visualize information.

### Common Elements of Controls in Data Models

The basic elements of controls are spread across several chapters since many of the chapters relate to controlling the performance of a functional team and of the overall project team. The elements of controls are a breakdown structure, a standard for comparison, and monitoring.
The breakdown structure’s function is to organize information. The volume of information in construction or any data model tends to be vast, and computers and users cannot benefit from modeling unless the information is properly organized. For this reason, one or more breakdown structures are discussed in several chapters. The standard for comparison and the monitoring serve the purpose of controlling performance. Project controls tend to be cyclically, looping through the stages of establishing a standard for comparison (e.g., a baseline), monitoring against the standard, and acting upon the monitored data to prevent the performance from veering off the standard. The standard for comparison and the monitoring are control elements also defined and found across several chapters.

## This book

In this book, we introduce methods that support this BIM-based and multi-tiered approach to construction management. Some of the methods build on traditional methods found in many construction management books, and some are new and more specific to BIM. Some of the methods rely on the support of other organizations, such as the owner and suppliers, and some are methods that the general contractor has full control over. Nevertheless all the methods are developed to ultimately help a general contractor achieve laminar flow by opening the work front of crews in a timely manner and by preventing a reverse workflow
Many construction project management books or sources speak either in the language of construction engineering or computer engineering. Construction engineers are often left without sufficient understanding of the logic and approaches of computer engineers, and vice versa. This gap is greater for a certain phase of a project’s lifecycle. While there are references that bridge this gap for designing, few references exist for bridging the gap for construction. The references helpful for construction are often either software-specific or briefly touch on the overarching and basic concepts of construction. Although this book will be useful for anyone in the industry at any phase, it is our intention to help the builders first—both Construction engineers and computer engineers involved in building. It is also an entry level book for people starting their career in this field. Its aim is to help civil engineers understand the fundamentals of construction and their relation to information modeling and management, and to help computer engineers understand the business rules of construction. The book prioritizes the needs of general contractors on medium to large projects, who can see the long-term value of developing a system that is holistic yet adaptable to differing project conditions. The book mainly presents concepts, terms, methods, and examples in the context of building construction (residential building, office tower, retail space, etc.), but similar or comparable concepts, terms, etc. exist in other construction sectors. Whenever comparing, benchmarking, or contrasting with the practices of other sectors is helpful, the book does so.
If by the time you have finished reading this book, you cannot implement and adopt the methods we developed, then this book would’ve failed to achieve its goals. For ‘the great aim of education’ said Herbert Smith, ‘is not knowledge but action’.
And this is an action book.