Between the Poles

European initiative to improve knowledge of the subsurface in cities

The challenge of increasing urbanization in a world where anthropogenic pressure on the environment has become threatening is driving the digitalization of urban planning and the design, construction and maintenance and operations of urban infrastructure. Building information modeling and laser and photogrammetric scanning of entire cities is resulting in comprehensive digital twins of the aboveground of cities. But the below ground has been neglected. There is a growing recognition that the subsurface needs to be included in urban planning and construction to reduce the risks of conflicts with subsurface infrastructure and to maximize the benefits of subsurface resources.

Over the last couple of years, the COST TU1206 Sub-Urban program has identified a knowledge and communication gap between subsurface experts, urban planners and decision makers. To bridge this gap it is necessary to improve information about the subsurface, ensure it is broadly accessible, and to make sure that the people receiving the information are able to understand and use the information to take decisions. The objective of the TU1206 Sub-Urban program is to transform the relationship between experts who are developing urban subsurface knowledge and those who can benefit most from it. The Sub-Urban program is developing a network to co-ordinate, integrate and accelerate research into modelling the subsurface in European institutions. 150 researchers in 30 countries are contributing to the Sub-Urban program. Nearly a hundred cities are participating in the program.

At a preconference workshop organized by Geodan and TNO at the GEO|Design+BIM conference in Amsterdam, Rob van der Krogt, Johannes de Beer and Ignace van Campenhout gave an overview of the work of the TU1206 Sub-Urban program. The program comprises geological survey organizations, cities, and research partners from the member states of the European Union. Its goal is to improve the management of the subsurface in Europe's cities and to open up knowledge about the subsurface to enable the smart cities of tomorrow. Its objectives are to coordinate cross-disciplinary research on the subsurface, share methodologies and knowledge, inform and empower policy and decision makers and broaden the relevance and impact of our knowledge about the subsurface to make it fully complementary to and interoperable with above ground 3D urban models.

To date the Sub-Urban program has produced nineteen City Reports covering the subsurface information available about specific European cities. It has also generated seven thematic reports related to subsurface topics including subsurface planning, geochemistry, geotechnical issues, geothermal energy, groundwater, data management, 3D modeling, and cultural heritage.

Navigating through the toolbox

A key goal of the program is to develop a Toolbox to enable subsurface knowledge to be widely disseminated. The Toolbox is a fit-for-purpose suite of recommended methodologies, good practices, guidance and case studies to enable the free flow of key subsurface data knowledge.

One of the challenges identified by the program is that urban planners are not talking to subsurface experts. For example, at the workshop Ignace van Campenhout gave an example where a new stadium was designed without consideration for the subsurface in a part of Rotterdam.

Planned site for new Rotterdam stadium and subsurface map showing abandoned oilfield.

It was discovered subsequently that a major underground gas pipeline goes through the middle of the site. It was also found that the site lies above an abandoned oil field, which would be an opportunity for using geothermal heat to reduce the carbon footprint of the stadium. To begin to get urban planners and designers and subsurface experts communicating was the motivation for the preconference workshop “Utilizing subsurface data for urban planning, design, construction and maintenance” organized by Geodan and TNO at the GEO|Design+BIM conference in Amsterdam which I blogged about yesterday.

The workshop was effective in illuminating the risk of decision making without information about the subsurface. Poor information about the subsurface costs the world economy trillions of dollars. What is underway in the Netherlands with the Key Registry for the Subsurface or BRO is the beginning of a practical solution to this problem and I expect that the TU1206 Sub-Urban program will be directly involved in BRO and will help disseminate information about the BRO program as it is implemented beginning in 2018.

Elevated risk in road construction lacking knowledge of the subsurface

The challenge of increasing urbanization in a world where anthropogenic pressure on the environment has become threatening is driving the digitalization of urban planning and design, construction and maintenance and operations of urban infrastructure. Building information modeling and laser and photogrammetric scanning of entire cities is resulting in comprehensive digital twins of the above ground infrastructure of cities. But the below ground has been neglected. There is a growing recognition that the subsurface needs to be included in urban planning and construction to reduce the risks of conflicts with subsurface infrastructure and to maximize the benefits of subsurface resources.

One of the challenges identified by the European COST Sub-Urban program is a communications gap between urban planners and subsurface experts. To begin to improve the level of communication between urban planners and subsurface experts, Geodan and TNO organized a preconference workshop “Utilizing subsurface data for urban planning, design, construction and maintenance” at the GEO|Design+BIM conference in Amsterdam.

Alternative routes for proposed highway

The workshop was a hands-on event with real data from a part of the Netherlands. It was led by Cindy Teeven and Ceciel Fruijtier from Geodan and Rob van der Krogt from TNO. In the simulation in which all participants in the workshop participated, a decision had to be made about the preferred route for a new highway. The alternatives were a route that skirted existing buildings and followed the route of an existing railway and regional road and a route that went through the countryside. An online GIS system provided layers of typical 2D information from public databases that might be relevant to the decision process including the location of existing residential and business buildings, historical and conservation sites, existing infrastructure such as roads and railways, and so on. Each of the participants was assigned a role to play: people of the place, traffic engineer, civil engineer, regional government, environmental authority, and local business council. After an hour with the data we were asked to report on the decision that had been reached on a preferred route. Primarily for reasons relating to reducing traffic through populated areas, the choice of most of the stakeholders was the route through the countryside. However, the “civil engineers” raised a red flag about this route because of the risk of poor soil conditions that could make this route challenging and expensive. Clay and peat, which are prevalent in the Netherlands, are susceptible to subsidence when a load is placed on them and are therefore to be avoided whenever possible when building any kind of structure. In contrast a great deal was known about the soil conditions of the alternative route because infrastructure and houses had been built along it for many years.

Surface elevations from lowest (blue) to highest (red)

After the first hour it was announced additional information was provided including a digital terrain model (DTM) showing surface elevation for the area and a model of the subsurface composition of the terrain – whether sand, peat or clay - to roughly 50 meters interpolated from bore holes and groundwater sampling sites in the region.

The DTM showed that the route skirting existing infrastructure was generally higher by a couple of meters than the alternative route through the countryside where the land was low lying suggesting subsidence. The subsurface soil composition model was used to create profiles showing the probability of clay and peat in the subsurface along the proposed routes. The 3D model revealed a high probability of clay and peat in the subsurface along the route through the countryside. In light of the new information about the subsurface, participants were requested again to arrive at a decision for the preferred route. Armed with the new subsurface information several of the stakeholders changed their minds. For the “civil engineers” the new subsurface information confirmed their fears about the risk of the route through the countryside.

The cost of an elevated highway or viaduct over the extensive peat and clay fields would be much more expensive than the alternative route skirting existing infrastructure. If the simulation had included cost and it had been made clear that the cost would have to be borne through a rate increase, I would expect that more of the stakeholders would have changed their minds.

Probability of clay in the subsurface along route from lowest (blue) to highest (red). Vertical dimension is depth.

It was explained at the end of the workshop that the workshop was based on a historical event in the north of Holland. At the time it was decided to build the route through the countryside. After extensive construction delays and rising costs, it was ultimately resolved in a high profile court case. The outcome was that the construction contractor and the regional government agreed to split the much higher cost of building a viaduct through the countryside.

The workshop was effective in illuminating the risk of decision making without information about the subsurface. In this case there was some data about the subsurface although historically it was only consulted after the initial decision. The reality in much of the world is that there is little information publicly available about the subsurface. Many construction projects proceed blindly with respect to what lies below the surface. In the United States poor information about what lies below the surface is the leading cause of construction delays and cost overruns. Construction bids are routinely inflated significantly to accommodate the risks associated with the lack of knowledge about the subsurface. Poor information about the subsurface costs the world economy trillions of dollars. What is underway in the Netherlands with the Key Registry for the Subsurface or BRO is the beginning of a practical solution to this problem. The world should be watching.

Key registry created in the Netherlands to help model the subsurface

Increasing urbanization throughout the world challenges the sustainable development and resilience of cities. Despite this, the importance of the ground beneath cities is often overlooked.  A lot of information about the underground is captured during excavation and drilling. But this data is typically stored in project or private databases and is not shared. Capturing this data in a shared, open database is a first step toward developing a model of the subsurface that can be reliably used for urban planning, design, construction and maintenance.  The Netherlands has recently embarked on a national program supported by legislation and standards to do just that.

At the preconference workshop “Utilizing subsurface data for urban planning, design, construction and maintenance” organized by Geodan and TNO at the GEO|Design+BIM conference in Amsterdam, Michiel van der Meulen of the COST Sub-Urban program presented an overview of a new program supported by legislation to develop and maintain an open database of information about the subsurface in the Netherlands.

Current data about the subsurface in the Netherlands comes from borehole logs, cone penetration tests, and groundwater measuring points. Most of the currently available information about the subsurface in the Netherlands comes from boreholes drilled typically to over 100 meters using light drilling equipment as well as some boreholes to much greater depths using heavy drilling equipment. This information is available for free through the DINOloket of the TNO, Geological Survey of the Netherlands.

Based on interpolating from the existing borehole data, there are several models of the subsurface in the Netherlands developed by the Geological Survey of the Nethelands. For example, there is a model of the subsurface down to 50 meters. It has a resolution of 100 by 100 by half a meter. It was intended to assist in identifying aquifers and gas fields. This is too course for city planning purposes. What an urban planner needs is much higher resolution and that will require more data.

In 2015 a new law was passed by the States General or parliament in the Netherlands creating a Basisregistratie Ondergrond (BRO) or Key Registry for the Subsurface. The law mandates that if you excavate or drill you have to share your data (relating to soils, geotechnics, and groundwater) with the registry. In addition if when using the data in the registry you find something is incorrect you have to report it. The registry is required to be open and accessible to all citizens of the Netherlands. This new registry will require new standards for recording data and there is a major effort underway in the Netherlands to develop these standards. The implementation of the new subsurface registry will begin in 2018.

The Key Registry for the Subsurface or BRO is intended to provide transparent and accessible information about the subsurface. It is subject to the government's open data policy. In addition to providing data for urban planning, design, construction and maintenance, it is intended to include an inventory of opportunities and risks relating to subsurface, provide data for sustainable water management and to support the governments goal of moving toward a carbon neutral economy at the national regional and local levels. It is also intended to reduce the costs associated with infrastructure management for soil remediation.

The overall goal is to initiate the process of organizing an information chain that will harness geological survey and city efforts in building databases and creating the necessary standards for information production about the subsurface. But to better serve cities with the subsurface information they need, Michiel van der Meulen said that we need to rethink geological mapping, rethink urban information management, and create new alliances among organizations involved in urban development. The new BRO key registry is an important first step in the process of developing models of the subsurface that can be joined seamlessly with above surface information to create the comprehensive digital twins that will be required by the smart cities of the future.

Geospatial data bill before Congress revised to its original intent

The Geospatial Data Act (GDA) of 2017, which was introduced earlier this year in the Senate (S.1253) and a companion bill in the House (H.R.3522), has some history. It was originally proposed in 2015 by Orrin Hatch, a Republican Senator from Utah, and sponsored by five Republicans and five Democrats. The 2015 bill consisted of 10 sections and basically codified and strengthened federal government practices relating to geospatial data. For example, it proposed that the chair of the Federal Geographic Data Committee (FGDC) be the Director of the Office Management and Budget (OMB), an agency that has statutory authority and can set standards and enforce practices for all government departments.  This would provide FGDC with the authority to make other agencies follow existing common sense rules. The bill established a clear vision, assigned responsibility, provided authority and ensured oversight of Federal activities by Congress. These improvements were intended to help ensure that the U.S. is able to build a robust National Spatial Data Infrastructure (NSDI).  The 2015 bill enjoyed wide support in the geospatial community throughout the U.S. and was generally viewed as a positive step forward.

However the 2015 bill was blocked in the Senate Committee on Commerce, Science, and Transportation. It has been suggested that MAPPS, an organization representing some engineering and surveying firms that is attempting to restrict procurement of geospatial services by extending the Brooks Act to cover the geospatial sector, was instrumental in getting the 2015 bill blocked in committee. As a result the 2015 bill was rewritten with two additional sections that broadly extended the definition of survey data and mandated rules (Brooks Act) for procurement of geospatial services by the federal government. 

The bill has now been revised back to its original intent.  The text of the revised House bill (H.R.4395) is on congress.gov and it does not include Section 11 and 12 which were intended to apply the Brooks Act to geospatial data and services and were not viewed positively by the broad gesopatial community.  The text of the revised Senate bill (S.2128) is not yet available.

Increasing proportion of U.S. jobs require digital skills

In a new report from the Brookings Institution Digitalization and the American workforce the changing requirements for digital skills for job types covering 90% of the U.S. workforce has found dramatic changes in the last 15 years.  As recently as 2002 under half of U.S. jobs required digital skills.  By 2016 70% of jobs required digital skills.  Almost a quarter of U.S. jobs now require high digital skills.

Virtually all industry groups saw increased digital skill requirements increase from 2002 to 2016.  The industries leading the digital charge were professional, scientific and technical services; media; and finance and insurance.  Trailing the pack are education, transportation and warehousing, basic goods manufacturing, and construction.  Looking at construction the report notes that in the period 2010-2016 construction output out rose by 2.7%, wages rose by 1.4%, and productivity decreased by -0.6%, highlighting the continuing challenge of productivity stagnation in the construction industry.  Among occupations construction labourers have the lowest digital skills, perhaps one of the reasons paper drawings still typify construction sites.

During this period the digital skill level of even the least digitalized occupations have risen.  Welders and heavy truck drivers saw their digtial skillls scores triple or more. By 2016 48 percent of low digital skills occupations employing 33 million workers had become medium-digital or even high-digital occupations.  Among the occupations transitioning from low digital scores to medium or high include tool and die makers and bus and truck mechanics.  Even at the very bottom end, the digital skills of construction laborers increased through not by enough to move them out of the low digital skills category.

 

Shortage of skilled trade workers drives prefabrication

At the Fall BIMForum/BuildCon conference in Dallas two presentations about actual prefabrication experience - for data centres and for large automotive plants - both mentioned shortage of skilled labour as an important motivation for turning to prefabrication for construction projects.  In addition to reducing onsite labour requirements, Improved quality, greater safety, faster project delivery, and in some cases reduced costs were mentioned as the key benefits of prefab.

A compelling presentation on the market drivers for and benefits of prefabrication for data centre infrastructure was given by Matthew Englert, Vice President at Rosendin Electric and President, Modular Power Solutions and Chris Crosby, CEO of Compass Datacenters. Data centers, which used to be defined in terms of servers and racks of servers, are now defined by containers of servers. Timing is of the essence for building data centres.  Compass advertises "We’ll deliver your dedicated data center in six months from breaking ground on a pad ready site or we’ll pay you $100,000."

The electric power requirements of data centres are reckoned in the hundred of kilowatts and even megawatts. A significant portion of the cost of a data centre is the electric power rooms to convert and manage the power for the servers and other equipment in data centres.

Both Chris and Matthew said that an important motivation for turning to prefabrication for the power rooms is the decline in the number and quality of the skilled tradesmen required to build power rooms. Older and more highly skilled trades people are retiring and they are not being replaced by younger people. This is partly a North American problem because there are limited apprenticeship programs. Perhaps because in the past skilled trades people were simply imported from Europe.

There are other advantages to prefabrication. It is easier to attract skilled workers to work in a plant under a roof with the amenities of factory environment as opposed to working outside often in inclement weather.  Weather is always a risk on a construction site.  Another advantage of a factory environment is safety. Statistics show that injuries are less in a prefab environment compared to a construction site. Quality is another factor that is easier to control in a prefab plant.

For data centre power rooms the prefab "skids" built by Modular Power Systems are huge weighing 60,000 to 80,000 pounds and requiring large flatbed trucks to deliver from the prefab plant to the construction site.  You can watch the construction of a couple of data centres at the Compass site and the power rooms are prefabbed offsite and delivered on flatbed trucks.  They are offloaded onto concrete pads that have been prepared in advance.  The process is very efficient and reduces the congestion of trades people at the construction site. 

Chris was blunt in his assessment of the appropriateness of existing BIM software for designing data centres. His perspective is that BIM software is no better than traditional CAD. The problem is that the level of detail (LOD) currently supported by BIM software is simply not detailed enough. He argues that if you are going to use 3D design software then mechanical design tools such as Solidworks are better than BIM tools.  He believes that BIM software is ripe for disruption. Designing buildings and other infrastructure in the future is going to require new design tools and that is going to require significant investment in new technology. This is a very similar sentiment to Greg Luth's perspective on the advantages of high definition building information modeling (HD BIM) for structural engineering of large manufacturing plants such as the Tesla Gigafactory in Nevada.

Based on his experience Chris believes that prefab always costs more the first time. Repetition is required to bring the costs down to where prefab is cheaper than stick built. Therefore Chris and Matthew are convinced that the next step is to move beyond prefab to manufacturing.

General Motors came to similar conclusions based on their experience in using Epsilon Industries prefabbed utility system upgrades for four GM automotive plants.  As presented by Jeffrey Johnson, Manager, Process Energy Initiatives, Bob Stevenson, Senior Vice President, Ghafari Associates, Chris Wiederick, President, Epsilon Industries, and Christopher Hofe, Project Director, Barton Malow Company, the problems that encouraged the GM team to prefab most of the utility components were a shortage of skilled trades and wanting to avoid congestion resulting from many trades tripping over each other at construction sites.  They estimated that prefabbing reduced their costs by about 20% and enabled them to deliver completed utility plant for the automotive factories in eight months instead of eighteen. For example, a complete chilled water system including a safety system and weighing 85 000 lbs was manufactured in Kingston, Ontario, trucked down and and was up and running in 2.5 weeks. Also since quality assurance for the chiller was completed in the factory in Kingston, the handover was virtually instantaneous compared to the prolonged period required for a stick built chiller.

For GM shortage of labour is a major problem and was a major motivator of the decision to use prefab components from Epsilon Industries.  The GM team repeatedly emphasized that they didn't know how they could have staffed stick build projects at these four sites.  Onsite congestion at a construction site is also a major problem that is relieved by prefabbing components.  Work conditions on a construction site are often poor because of bad weather. Weather is always a risk that can hold up a stick built project.  They also reported that supervising in a factory environment is much easier compared to a construction site.  GM found it easier to recruit labour for a factory environment and they was able to retain better quality labour, people who wanted to settle down, as opposed to the high proportion of transients typical of construction projects.

HD BIM used to design Tesla Gigafactory in record time

At the Fall BIMForum/BuildCon conference in Dallas, an entralling presentation about how HD BIM was used to build five buildings of the Tesla Gigafactory in Nevada in record time was given by Greg Luth of Gregory P. Luth & Associates (GPLA). HD BIM is "high definition building information modeling" and refers to BIM modeling that is detailed enough (LOD 400) that what are called "shop drawings" can be produced from the BIM model.  Shop drawings include, literally, the nuts and bolts for structural steel and rebar in the case of reinforced concrete structures.

GPLA is a structural engineering company which has comprised between 10 and 16 engineers at different times.  Greg described a number of projects that GPLA had completed using the HD BIM approach.  The first in 2006 was the USC School of Cinematic Arts where the HD BIM approach proved itself very successfully saving 20% in costs and 30% in time.

The Tesla Gigafactory project involved five buildings, 3.5 million square feet, 32,000 tons of structural steel, and 2,500 tons of rebar.  All the steel and rebar shop drawings were produced from the BIM model.  The structures for all five buildings were delivered only seven months after GPLA received the first telephone call from Tesla.

BIM LOD specification released under open Creative Commons license

At the Fall BIMForum/BuildCon conference in Dallas, BIMForum announced the 2017 release of the Level of Development (LOD) specification.  The Level of Development (LOD) Specification is a reference that enables practitioners in the AEC Industry to specify with a high level of clarity the content and reliability of Building Information Models (BIMs) at various stages in the design and construction process.  The 2017 specification has been released under a Creative Commons license that allows anyone to use the LOD specification non-commercially with attribution and no derivatives.  In other words you can use it for free, as long as you don't sell it, that you include attribution to BIMForum and that you don't change it. 

The 2017 release also includes levels and grids and five types of coordinate systems; assembly or object coordinates, local building coordinates, local campus coordinates, state plane or civil coordinates and geospatial or GIS coordinates.  BIMForum is encouraging software developers to become aware of the new LOD specification in hopes that they will integrate it into design and construction software applications.

In April 2014 at the Spring BIMForum in Boston James Vandezande and Will Ikerd gave a summary of the BIMForum's recently released LoD specification.  It was intended to allow authors to define what their models can be relied on for, and to allow downstream users to clearly understand the usability and the limitations of models they are receiving.  The specification did not prescribe what Levels of Development are  reached at what point in a project. Its primary objectives were;

• To help teams, including owners, to get a clear picture of what will be included in a BIM deliverable
• To help design managers communicate the level of detail that needs to be provided at various points in the design process
• To provide a standard that can be referenced by contracts and BIM execution plans.

Version 1 of the specification which was released in 2013 included LOD levels upto 400

• LOD 100 - A model element may be graphically represented in the model with a symbol or other generic representation.
• LOD 200 - A model element is graphically represented as a generic object  with approximate quantities, size, shape, location, and orientation.
• LOD 300 - A model element is graphically represented as a specific object  with quantity, size, shape, location, and orientation.
• LOD 350 - A model element is graphically represented as a specific object with quantity, size, shape, orientation, and interfaces with other building systems.
• LOD 400 - A model element is graphically represented as a specific object with size, shape, location, quantity, and orientation and with detailing, fabrication, assembly, and installation information.

The specification has been accepted into the National BIM Standard (NBIMS) and a number of major organizations have adopted and are using it including the U.S. Army Corps of Engineers, Mayo Clinic, and Massport.

In April 2014 at the Spring BIMForum in Boston James Vandezande and Will Ikerd gave a summary of the BIMForum's recently released LoD specification.  It was intended to allow authors to define what their models can be relied on for, and to allow downstream users to clearly understand the usability and the limitations of models they are receiving.  The specification did not prescribe what Levels of Development are  reached at what point in a project. Its primary objectives were;

• To help teams, including owners, to get a clear picture of what will be included in a BIM deliverable
• To help design managers communicate the level of detail that needs to be provided at various points in the design process
• To provide a standard that can be referenced by contracts and BIM execution plans.

Version 1 of the specification which was released in 2013 included LOD levels upto 400

• LOD 100 - A model element may be graphically represented in the model with a symbol or other generic representation.
• LOD 200 - A model element is graphically represented as a generic object  with approximate quantities, size, shape, location, and orientation.
• LOD 300 - A model element is graphically represented as a specific object  with quantity, size, shape, location, and orientation.
• LOD 350 - A model element is graphically represented as a specific object with quantity, size, shape, orientation, and interfaces with other building systems.
• LOD 400 - A model element is graphically represented as a specific object with size, shape, location, quantity, and orientation and with detailing, fabrication, assembly, and installation information.

The specification has been accepted into the National BIM Standard (NBIMS) and a number of major organizations have adopted and are using it including the U.S. Army Corps of Engineers, Mayo Clinic, and Massport.