Findings Practice in both NA and the EU is governed by overarching design and construction documents that are heavily influenced by local practices and local codes. Both regions utilize the same equipment and similar design methodologies, and both are developing new innovations. EU innovation is more focused on drilling and construction site activities such as in-boom locating devices. Representatives from the EU are currently examining concreting practices and plan to publish their conclusions in the near future. In NA, the innovations are focused on QA/QC, or post process needs such as in-cab readouts, hole measurement devices, and Thermal Integrity Profiling. Although many of these measurement devices are more widely used in NA, often they were developed in Europe. Both regions exhibit less conservatism in design when stronger, more realistic geotechnical investigation materials are available. practice using fewer diameters for its designs and, in general, the diameters used in the EU tend to be smaller than in NA. The use of Design Build (DB) or variations thereof as opposed to Design Bid Build (DBB) are far more prevalent in the EU than in NA. In addition, the EU seems more advanced in selecting contractors based on value versus price. QA/QC testing is performed on a smaller percentage of shafts in the EU than in NA. The EU depends more on analytical design and in some cases load testing rather than integrity testing for design assurance. Why do we see these differences? The task force concluded that many of these differences can be attributed to risk issues including: quality, productivity, safety, schedule, cost, public disruption and sustainability. Risks are often the direct result of decisions related to specialty subcontractor selection, and/or design type selection. Drilled shafts to support a concrete plant in Calgary, Canada (photo courtesy BAUER Spezialtiefbau GmbH) Bored pile construction in Switzerland (photo courtesy BAUER Spezialtiefbau GmbH) public private partnerships or Build, Oper- ate, Transfer) many, if not all, risks are borne by the DB contractor, who then either shares them within its team on an ability-to-pay basis or finds insurance protection for them. DB contractors in NA tend to be larger conglomerates that coordinate design, construction, testing and often financing issues as well as long-term maintenance. In the end, decisions are made based on economic reasons. Short-term efficiencies often do not equate to long-term economies. Even conventional contracts, which are awarded based on a value rather than price basis, usually come with increased builder liability and responsibility. If one accepts the premise that, to the DB contractor, the long-term economic decision is paramount, then some of the differences identified in this study are easier to understand. It is a basic assumption contained herein that this premise governs DB in both the EU and NA. For example, slurry protected shafts are In general, the EU utilizes a larger percentage of cased shafts while NA constructs a higher percentage of shafts using slurry protection. In the slurry practice, the use of mineral slurries is predominant in the EU while polymer is prevalent in NA. The EU has standardized Influence of Project Delivery Methods In the NA low bid environment of DBB, risks are shared or volleyed between the various entities. In contrast the DB environment (including such things as often cheaper to construct than cased shafts, but suffer a higher incidence of anomalies. Anomalies drive schedule losses, which are often not considered by DBB contractors. However a DB contractor, who is responsible for financing, has a different perspective. If cased shafts are DEEP FOUNDATIONS • NOV/DEC 2016 • 105
