Evolution of BIM technology has augmented information rich BIM models with the additional dimensions of scheduling and material/cost estimation. 4D and 5D BIM models enable better planned and more cost effective construction.
4D and 5D BIM are riding the BIM technology wave and are set to revolutionise the construction industry. By integrating information rich 3D BIM models with additional dimensions of scheduling and cost/material estimation, 4D and 5D BIM better manage the effect of change orders on project costs and scheduling. This promises to reverse the construction industry’s annual losses pegged at $177B due to poor communication, rework and bad data management.
So, what are the major causes of cost and schedules overrun?
- Inaccurate project planning during the initial construction stages.
- Inaccurate project estimates during initial stages due to absence of sufficient data.
- No planning or readiness for change orders.
- Administration errors caused due to system flaws or human errors.
- Poor operational work flow and un- streamlined processes.
Advantages of 4D BIM
4D BIM adds the time factor in the form of scheduling data into 3D models. Time-related information for any element includes information about lead-time, the time it takes to install or construct, the time needed for it to become operational, the sequence in which the components are to be installed as well as dependencies on other areas of the project.
Clash-free Construction Scheduling
It generates information about the schedules of building products and creates a visual in a step-by-step method. For different building components, 4D BIM incorporates time related information like lead-time, construction and installation time, allowances for drying and mixing period, and inter dependency on other products.
The £8.4bn worth Greenwich Peninsula transformation is London’s largest single regeneration project. It aims to provide 15,720 new homes in seven new neighborhoods, a new film studio, a new design district, schools, offices, health services and public spaces – all within a 1.6 mile stretch along the Thames.
A project of this scope required scheduling of multiple elements. 4D simulation facilitated progress monitoring against the construction program. Look-ahead workshops with the subcontractors threw light on how the façade system would be set up (there were some 17 façade elements in a single asset!), taking into account the geometry, logistics, resources (equipment) and timeline. 4D BIM technology also facilitated effective planning on when equipment was needed on site and managing this around other parallel construction activities of the project.
4D Graphical Representation
The scheduling data is easily convertible into graphical representation, which helps in comparing the scheduled plan with the actual plan.
The University of Virginia (UAV) Health System University Hospital is one of the few trauma centers in the region with a footfall of 20 patients each day via helicopter. The hospital needed to expand its 440,000 square feet premises without affecting daily operations and services.
The project and design team put 4D BIM technology into operation. Revit, Navisworks and BIM 360 cloud services were used to seamless coordinate and plan construction sequence in a way that helicopter pilots could safely land and take off from their helipad which was as close as 30 feet away from construction activities and operating cranes. These operations were managed for close to 22 months in a normal manner!
Optimal Resource Utilization
Properly planned data in the form of graphs and datasheets lends greater visibility and aids resource mobility and better resource planning. The coordinated approach also helps in optimal resource utilization, achieving higher operational efficiencies and in meeting timelines.
China Zun tower is the tallest structure in Beijing with 108 floors across a gross floor area of 43.7 million square meters. Construction completion of this project was timed at an aggressive 62 months, 1.4 times faster than projects of same size. The project team created 652 BIM models and 800 component families to facilitate construction coordination and workflow. For the 6.5 meters thick base slab of the tower, 56,000 cubic meters were required to be poured all at once. The BIM workflow simulated the entire pouring process and associated resource and equipment logistics. This seamless and meticulous coordination resulted in the project being completed in 93 hours – seven hours less than estimated.
Better Interdisciplinary Coordination
Since the reworks are minimized and each worker on site is adequately informed about what he would be working upon at a particular phase of construction project, there is better coordination among various disciplines. The contractors can easily link this with activities of other disciplines and plan in a logical manner by maximizing the work efficiency of each worker on construction site.
A UK based architectural firm had challenges of inter-woven building plans at five different levels and modeling exact elements was a huge challenge. The technical instructions were in foreign language and MEP drawings lacked dimensions for pipe and systems.
Hitech CADD Services developed a federated/coordinated 4D BIM model for construction scheduling using Revit and Navisworks respectively. Interdisciplinary clashes were detected and eliminated to develop a coordinated model. A clash free federated 4D Revit BIM model was delivered to client accompanied with a project introduction video having photo realistically rendered models, which helped the client gain design intent, save costs and rework.
Advantages of 5D BIM
5D BIM, the next step up from 4D (time scheduling), integrates design with estimating and costing, including generation of quantities, development of rates and overall cost.
Enhanced Cost Forecast and Estimation
The exact quantity of various building components generated by higher level of detailing with manufacturer details from the 3D models can be compared with the current purchasing rates to estimate the cost for entire structure.
A leading project management solutions provider in Saudi Arabia required interdisciplinary clash detection, material takeoffs and scheduling during ongoing construction work. Hitech created information rich BIM model with LOD 500 as per AIA standards, for MEP, architectural and structural disciplines by using Autodesk Revit and Navisworks. Accurate material take-offs and construction scheduling using Navisworks provided more accurate cost estimation and smoother construction activities.
More Accurate and Faster Quantity Take offs
On an average, estimators spend 50% to 80% of their time in creating a quantity take off for cost estimating. When the process is automated, it reduces human errors, saves cost and time. With more time on their hands, estimators can focus on other important project specific factors like assessing financial risk factors and identifying construction assemblies involved, generating pricing etc.
Over 60% of construction failures are due to economic factors, mostly because of lack of liquidity on daily activities. This problem is simply solved by linking cost information to the traditional 3D model and scheduling, also known as 5D BIM. This dimension allows the instant creation of financial estimations against time, greatly reducing the time consuming task of quantifying resources and estimating costs from days to minutes while also minimizing errors.
Automated Quantity take offs as per Design Modifications
Whenever a single component is modified, the direct impact on the cost is calculated automatically. By using BIM model instead of drawings, the take-offs, counts and measurements are generated directly from the underlying model. Therefore, the information is always consistent with the design. When any change is made in the design, the change automatically ripples to all related construction documentation and schedules, take-offs, counts and measurements that are used by the estimator.
Easy Selection of available Options
Accurate and quick estimation while analysing various design options within a fraction of time makes it easier for the architect to choose design option as per the client’s requirements. This also helps owners, contractor and sub-contractors during bidding phase.
Addition of cloud technology to BIM allows access of data from anywhere and on any device to contractors and project managers. This helps them coordinate better with their teams on schedules or change in design or plans.
A Futuristic View
6D BIM provides for additional information related to operation and facility maintenance which gives a better understanding of the whole-life-cost of asset along with the cost of construction. This additional data may contain information on component manufacturers, installation and maintenance details, decommissioning data and energy performance throughout its life span. Thus, the pre-planned O&M eases better facility management in terms of cost and sustainability.
IOT-based data driven scheduling tools like IBM Maximo and Watson IOT not only provide real time weather data but also manage work orders. Combining cost data with scheduling in cloud based platforms like BIM 360 enables stakeholders to track cost data and site data in real-time on any device at any time. Thus, it not only improves productivity, site safety and project management but also facilitates informed decision making to meet unpredictable or unexpected situations during construction.
It is apparent that 4D and 5D BIM are revolutionizing the construction industry. The integration of information rich 3D BIM models with added dimensions of scheduling (4D) and cost/material estimation (5D) ensure better management of change orders on project costs and scheduling. Integration of the cloud technology with BIM, allows stakeholders to access data from anywhere on any device.
Governments in most countries across the world have mandated BIM adoption for professionals in the AEC sector. There are clear directives to implement new trends in BIM technology for efficient deployment of resources, planning, designing, managing and reducing rework during the construction process. As Disney said, “The way to get started is to quit talking and begin doing!”