Design for value and enhanced functionality
Value engineering should be about maximizing value, not simply reducing costs, but this is a shift from established thinking, writes Jonathan Cook of Tensar.
Value engineering is about maximizing the overall value for the stakeholders of a project.
Giving a keynote address in October 2018 to the Chartered Association of Building Engineers following the Grenfell Tower disaster, Dame Judith Hackitt, former executive chair of health and safety, said value engineering was a phrase she would be “happy never to hear again”. ; it’s anything but value, it’s reducing cost and quality”.
The construction industry can often equate cost reduction directly with increased value, but ignore that cost has a direct impact on the delivery of functionality. If a reduction in cost leads to a disproportionate reduction in functionality, then a cost reduction can lead to reduced value. Clearly, the complete definition of the required functionalities is essential, and all the functional requirements of the stakeholders must be studied, clarified and defined, before any modification of the engineering of the value is proposed.
Value engineering has its place
Value engineering identifies opportunities to reduce costs, while improving functionality. The goal is to meet the functional performance requirements of the project at the lowest cost – preferably, the lowest total cost.
For construction projects, this means investigating the availability and cost of materials, construction methods, transportation, project-specific restrictions, as well as stakeholder issues and benefits, environmental impacts and durability. Adopting new and innovative materials and methods, such as substituting materials and methods with cheaper alternatives, can significantly reduce costs, but must do so without reducing functionality.
The importance of defining functionality
Functional analysis is an established technique that can be used to identify and quantify the requirements or value criteria of all stakeholders.
Example of stakeholder value criteria for a retaining wall project:
|Client – project owner||
|The neighboring merchants||
|Employees and public||
|environmentalist and ecologist||
The impact of any change in method should be assessed against each of the value criteria. Functionality is therefore not just about ensuring that a specific function is performed, but how well it is performed (performance), for how long it is actually performed (lifespan) and with what social and environmental consequences (impact).
When can value engineering be applied?
Value engineering can be applied at any stage of a project, but the earlier it is considered, the greater the potential for increasing value.
The figure below (extracted from RISC Guidance Note 5) illustrates how the early application of value engineering has the potential to have the most benefits for all stakeholders.
Skilled designers improve performance, functionality and environmental impact while reducing costs and have long understood the importance of early involvement in the project. In this way, recognized experts have been able to contribute with alternative approaches that offer real value to stakeholders, such as extending the life of new pavements to minimize future traffic disruptions and financial and environmental impacts. associates.
During the pre-construction stages of projects, companies partner with contractors to develop and implement value engineering alternatives that have major value impacts, such as redesigning support structures of land to enable the use of on-site waste as structural backfill – reducing disruption to local traffic and reducing overall carbon emissions.
Let’s see how geotechnical value engineering can provide benefits to stakeholders even on simple projects with relatively low geotechnical risk. Consider an access road to allow for the construction and future maintenance of a heathland wind farm. The fillers are well defined and this is a pristine site with no previous development so no complications are to be expected. A site survey was carried out, focusing on turbine locations with only one or two test pits along the road alignment. The subsoil was found to be variable, say 1.0-3.0% CBR. The access roads were designed taking into account the subgrade and using the CBR value of 1.0%. The resulting design required a 900mm thick granular layer, or 550mm with an incorporated stabilizing geogrid.
But what if a value engineering approach was taken to reassess the access road design? The value engineer can explore the potential benefits of modifying vehicle load. For example, by reinforcing the roads between wind turbine locations, the mobile crane can be moved between locations on heavier vehicles with only partial dismantling. This will increase road construction costs but greatly optimize crane utilization, with consequent reductions in rental costs for the contractor and potentially an earlier completion date for the client.
Alternatively, a small amount of additional investigative work on site could map the locations of weaker soil areas. The value engineer could then consider varying the design profile based on the actual strength of the subsoil. The thickness of the stabilized layer will then vary, with perhaps the majority at 250mm thick, and with only limited areas up to 550mm. In addition, construction traffic can be reviewed. Sections of road closer to the site entrance will carry all construction traffic, while sections of road farther from the entrance will carry significantly fewer construction vehicles. The stabilized road design can be adjusted accordingly, rather than assuming the same load case everywhere. This results in a gradual reduction in layer thickness as the roads progress through the site.
By reducing the thickness of the stabilized layer, the volume of imported quarry aggregates is reduced. The overall savings would be considerable, reduce construction costs and time, and easily cover additional site survey costs. In addition, reducing imported aggregates has other cost and environmental benefits: transport costs are reduced, disruption and damage to local roads is reduced, and energy costs and carbon costs of construction are also significantly reduced.
Value engineering on this simple project offers significant cost savings for the contractor, as well as real benefits for local stakeholders and the environment.
- Jonathan Cook is Senior Product Manager at Tensar