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Landslide Questions

What is a landslide?

A landslide is defined as the movement of a mass of rock, debris, or earth down a slope due to gravity. The materials may move by falling, toppling, sliding, spreading, or flowing.

Landslide Animation:

What causes a landslide?

Almost every landslide has multiple causes. Slope movement occurs when forces acting down-slope (mainly due to gravity) exceed the strength of the earth materials that compose the slope. Landslides can be triggered by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors.

What are submarine landslides?

Earthquake shaking and other factors can also induce landslides underwater. These landslides are called submarine landslides. Submarine landslides sometimes cause tsunamis that damage coastal areas.

Where do landslides occur?

Landslides in the United States occur in all 50 States. The primary regions of landslide occurrence and potential are the coastal and mountainous areas of California, Oregon, and Washington, the States comprising the intermountain west, and the mountainous and hilly regions of the Eastern United States. Alaska and Hawaii also experience all types of landslides.

How fast do landslide travel?

Landslides can move slowly, (millimeters per year) or can move quickly and disastrously, as is the case with debris flows. Debris flows can travel down a hillside at speeds up to 200 miles per hour (more commonly, 30 – 50 miles per hour), depending on the slope angle, water content, volume of debris, and type of earth and debris in the flow. These flows are initiated by heavy periods of rainfall, but sometimes can happen as a result of short bursts of concentrated rainfall or other factors in susceptible areas. Burned areas charred by wildfires are particularly susceptible to debris flows, given certain soil characteristics and slope conditions.

Why study landslides?
Landslides are a serious geologic hazard. It is estimated that in the United States they cause in excess of $1 billion in damages and from about 25 to 50 deaths each year. Globally, landslides cause billions of dollars in damages and thousands of deaths and injuries each year.

Who is most at risk for landslides?

As people move into new areas of hilly or mountainous terrain, it is important to understand the nature of their potential exposure to landslide hazards, and how cities, towns, and counties can plan for land-use, engineering of new construction and infrastructure, and other measures which will reduce the costs of living with landslides. Although the physical causes of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land-use management regulations can reduce landslide hazards.

Do human activities cause landslides?

Yes, in some cases human activities can be a contributing factor in causing landslides. Many human-caused landslides can be avoided or mitigated. They are commonly a result of building roads and structures without adequate grading of slopes, of poorly planned alteration of drainage patterns, and of disturbing old landslides.

Where can I find landslide information for my area?

The USGS National Landslide Information Center (NLIC) is a part of the U.S. Geological Survey Landslide Hazards Program that collects and distributes all forms of information related to landslides. The NLIC is designed to serve landslide researchers, geotechnical practitioners engaged in landslide stabilization, and anyone else concerned in any way with landslide education, hazard, safety, and mitigation. Every state in the US has a geoscience agency and most have some landslide information. The Association of American State Geologists provides links to the State Geologist for every state.

What was the most expensive landslide to fix in the United States?

The Thistle, Utah, landslide cost in excess of $200 million dollars to fix. The landslide occurred during the spring of 1983, when unseasonably warm weather caused rapid snowmelt to saturate the slope. The landslide destroyed the railroad tracks of the Denver and Rio Grande Western Railway Company, and the adjacent Highway 89. It also flowed across the Spanish Fork River, forming a dam. The impounded river water inundated the small town of Thistle. The inhabitants of the town of Thistle, directly upstream from the landslide, were evacuated as the lake began to flood the town, and within a day the town was completely covered with water. Populations downstream from the dam were at risk because of the possible overtopping of the landslide by the lake. This could cause a catastrophic outburst of the dam with a massive flood downstream. Eventually, a drain system was engineered to drain the lake and avert the potential disaster.

How many deaths result from landslides?

An average of between 25 and 50 people are killed by landslides each year in the United States. The worldwide death toll per year due to landslides is in the thousands. Most landslide fatalities are from rock fall, debris-flows, or volcanic debris flows.

What should I know about wildfires and debris flows?

Wild land fires are inevitable in the western United States. Expansion of human development into forested areas has created a situation where wildfires can adversely affect lives and property, as can the flooding and landslides that occur in the aftermath of the fires. There is a need to develop tools and methods to identify and quantify the potential hazards posed by landslides produced from burned watersheds. Post-fire landslide hazards include fast-moving, highly destructive debris flows that can occur in the years immediately after wildfires in response to high intensity rainfall events, and those flows that are generated over longer time periods accompanied by root decay and loss of soil strength. Post-fire debris flows are particularly hazardous because they can occur with little warning, can exert great impulsive loads on objects in their paths, and can strip vegetation, block drainage ways, damage structures, and endanger human life. Wildfires could potentially result in the destabilization of pre-existing deep-seated landslides over long time periods.

How do landslides cause tsunamis?

Tsunamis are large, potentially deadly and destructive sea waves, most of which are formed as a result of submarine earthquakes. They may also result from the eruption or collapse of island or coastal volcanoes and the formation of giant landslides on marine margins. These landslides, in turn, are often triggered by earthquakes. Tsunamis can be generated on impact as a rapidly moving landslide mass enters the water or as water displaces behind and ahead of a rapidly moving underwater landslide.

What are some examples of landslides that have caused tsunamis?

The 1964 Alaska earthquake caused 115 deaths in Alaska alone, with 106 of those due to tsunamis generated by tectonic uplift of the sea floor, and by localized subareal and submarine landslides. The earthquake shaking caused at least 5 local slide-generated tsunamis within minutes after the shaking began. An eyewitness account of the tsunami caused by the movement and landslides of the 1964 Alaska earthquake.

Research in the Canary Islands concludes that there have been at least five massive volcano landslides that occurred in the past, and that similar large events may occur in the future. Giant landslides have the potential of generating large tsunami waves at close and also very great distances and would have the potential to devastate large areas of coastal land as far away as the eastern seaboard of North America.

Rock falls and rock avalanches in coastal inlets, such as those that have occurred in the past at Tidal Inlet, Glacier Bay National Park, Alaska, have the potential to cause regional tsunamis that pose a hazard to coastal ecosystems and human settlements. On July 9, 1958, a magnitude M 7.9 earthquake on the Fairweather Fault triggered a rock avalanche at the head of Lituya Bay, Alaska. The landslide generated a wave that ran up 524 m on the opposite shore and sent a 30-m high wave through Lituya Bay, sinking two of three fishing boats and killing two persons.

How soon does the danger of landslides end after the rain stops?

It’s not possible to exactly predict the number of days or weeks that landslides remain a danger after heavy rain. Residents near mountain slopes, canyons, and landslide prone areas should stay alert even after heavy rain subsides.

Why is southern California vulnerable to landslides?

Areas that have been burned by recent wildfires are highly susceptible to debris-flow activity that can be triggered by significantly less rainfall than that which triggers debris flows from unburned hill slopes.

What was the biggest landslide in the world?

The world’s biggest historic landslide occurred during the 1980 eruption of Mount St. Helens, a volcano in the Cascade Mountain Range in the State of Washington, USA. The volume of material was 2.8 cubic kilometers (km).

What was the biggest prehistoric landslide?

The world’s biggest prehistoric landslide, discovered so far on land, is in southwestern Iran, and is named the Saidmarreh landslide. The landslide is located on the Kabir Kuh anticline in Southwest Iran at 33 degrees north latitude, 47.65 degrees east longitude. The landslide has a volume of about 20 cubic kilometers, a depth of 300 m, a travel distance of 14 km and a width of 5 km. This means that about 50 billion tons of rock moved in this single event!

Source: http://www.weatherwizkids.com

Deadliest Landslides In Recorded History

Some single landslide events have killed numbers in excess of the populations of small countries.

Landslides are life-threatening events that can make it seem as though the world we live upon is crumbling around us. Those landslides listed below are some of the deadliest in recorded human history, each taking away human life by the thousands.

10. Diexi Slides, Sichuan, China, August 1933 (3,000+ deaths)

On August 5, 1933, a strong earthquake triggered a massive landslide in Diexi, Mao County, Szechwan, China. The event, known as the Diexi Slides, claimed more than 3,000 lives, and destroyed many villages within the affected region. The old town of Diexi suffered the worst fate of all as it sank into the landslide-created dam below.

9. Khait Landslide, Tajikstan, July 1949 (4,000 deaths))

For centuries, the mountainous belt running through Central Asia has witnessed a large number of disasters involving earthquake-triggered landslides. One such natural catastrophe occurred in July of 1949, when the 7.4 magnitude Khait Earthquake triggered hundreds of landslides near the southern limits of the Tien Shan ranges in central Tajikistan. The adjacent valleys of Yasman and Khait were the most affected by these earthquake-induced landslides. The Khait Landslide involved rockslides with saturated loess travelling at an estimated average velocity of around 30 meters per second. Approximately 4,000 people were killed in this tragic natural disaster.

8. 62 Nevado Huascaran Debris Fall, Ranrahirca, Peru, January 1962 (4,500 deaths)

Mount Huascarán is a famous Peruvian mountain with a snowcapped peak that rises to a height of 22,205 feet. In January of 1962, a thaw triggered the breaking off of a portion of the north summit of the mountain, leading to a landslide/avalanche that led to the tragic death of nearly 4,500 people. The avalanche, locally referred to as ‘Huayco’, involved a massive ice sheet that was estimated to be about 1 kilometer wide and 40 feet high. As the ice sheet moved rapidly down the slopes, it gathered rock and debris from the mountain and strengthened in force, completely burying several villages in Ranrahica underneath it.

7. Huaraz Debris Flows, Ancash, Peru, December 1941 (5,000 deaths)

In December of 1941, the residents of Huaraz, a Peruvian city in the Ancash region, were completely unaware that a retreating glacier tongue above their city would soon be responsible for wreaking havoc its people and claim thousands of the lives living within. Just before dawn on December 13, 1941, disaster struck the Peruvian city when a landslide resulted in glacial ice crashing down into Lake Palcacocha, generating huge waves that completely destroyed the dam on the lake. This released large volumes of water, itself laden with mud, rock, and ice, into the valley below with an unimaginably high force. Another dam in the nearby Lake Jircacocha was also broken by the flowing glacial water, resulting in the furious waters of both of the two lakes emptying themselves onto the city of Huaraz, claiming more than 5,000 lives in the process.

6. Kelud Lahars, East Java, Indonesia, May 1919 (5,000+ deaths)

Mount Kelud, in Eastern Java, Indonesia, is quite infamous as an extremely active, hazardous volcano, and one which has erupted about 30 times in the past killing thousands of people in its volcanic disasters. One of the deadliest eruptions of this volcano occurred on May 19, 1919, when over 38 million cubic meters of water were expelled from the crater lake of the volcano, which had accumulated large amounts of sediment and volcanic material to form lethal lahars. The lahars moved down the mountains with high velocity and swept away and drowned all that were unfortunate enough to be in its path.

5. North India Flood mudslides, Kedarnath, India, June 2013 (5,700 deaths)

One of the worst natural disasters in the history of India occurred in June of 2013, when powerful flash floods killed around 5,700 people in the Himalayan state of Uttarakhand. Consistent cloudbursts and incessant monsoon rainfall were primarily held responsible for the disaster, which has been officially termed as a natural calamity. However, a section of environmentalists, scientists, and the educated public think otherwise. According to them, thoughtless human intervention in the Himalayan mountain ecosystem had rendered the ecosystem extremely fragile and prone to disaster. The unchecked tourism in the region had promoted the rapid growth of hotels, roads, and shops throughout the region without paying heed to the environmental laws and demands of the ecosystem. The mushrooming of hydroelectric dams in Uttarakhand was also another important factor held responsible for the environmental damage. Heavy rainfall had been previously recorded in the region which had also led to flash floods, but the devastation produced in 2013 was comparable to no earlier data. It is believed that floodwaters had no outlets this time, as most of the routes taken by the water previously were now blocked by sand and rocks. Hence, the lethal waters, laden with debris from dam construction and large volumes of mud and rocks, inundated towns and villages and buried all forms of life that came in its way.

4. 70 Nevado Huascaran Debris Fall, Yungay, Peru, May 1970 (22,000 deaths)

In May of 1970, an earthquake triggered a massive series of landslides and avalanches of rock and snow that buried the towns of Yungay and Ranrahirca. Nearly 22,000 people perished in this natural disaster. The avalanche travelled a distance of 16.5 kilometers. It ended up carrying 50-100 million cubic meters of water, mud, and rocks, which reached the village of Yungay and smothered all life forms therein under its deadly cover.

3. Armero Tragedy, Tolima, Colombia, November 1985 (23,000 deaths)

A dormant volcano, the Nevado del Ruiz in Tolima, Colombia, suddenly came to life on November 13, 1985, wreaking havoc on the nearby villages and towns, and killing as many as 23,000 people. A pyroclastic flow from the crater of the volcano had melted the glaciers in the mountain and sent deadly lahars, saturated with mud, ice, snow, and volcanic debris, rushing down the mountain at killer speeds towards the residential areas directly below it. The lahars soon engulfed the town of Armero, killing thousands there, while casualties were also reported in such other towns as Chinchiná

2. Vargas Tragedy, Vargas, Venezuela, December 1999 (30,000 deaths)

The Winter of 1999 witnessed unusually heavy rainfall in the Vargas State of Venezuela. The rainfall triggered a series of large and small flash floods and debris flows that claimed around 30,000 lives in the region. As per estimates, approximately 10% of the population of Vargas perished in the disaster. The entire towns of Carmen de Uria and Cerro Grande completely vanished under the mud bed, and a large number of homes were simply swept away into the nearby ocean.

1. Haiyuan Flows, Ningxia, China, December 1920 (100,000+ deaths)

The 8.5-magnitude Haiyuan Earthquake was the world’s second deadliest earthquake of the 20th Century. It generated a series of 675 major loess landslides causing massive destruction to lives and property. The natural calamity which struck the rural district of Haiyuan on the evening of December 16, 1920 claimed over 100,000 lives, and severely damaged an area of approximately 20,000 square kilometers. The worst affected areas included the the epicenter of the earthquake in the Haiyuan County in what is now the Ningxia Hui Autonomous Region, as well as the neighboring provinces of Gansu and Shaanxi. Haiyuan County alone lost more than 50% of its population in the disaster. One of the landslides buried an entire village in Xiji County as well.

Source: https://www.worldatlas.com

BIM Level of Detail (LOD) – Get ideas of each stage of a BIM modeling process

LOD stands for Level of Detailing in BIM. This specification determines the nature of the BIM Model based on the client requirement. It is not always important to detail the model in totality. We can work on need based BIM Models that can differentiate the stages based on the Level of Detailing. Typically a BIM model helps in denoting the amount of details or intricacies for a building.

LOD is the measuring criteria of the utilization of a model. These standards are determined by construction bodies appointed by the Government for effective implementation at different stages. Architects and Engineers work on BIM projects based on these standards. The standards of LOD for BIM are defined below

LOD 100 (Conceptual design/Schematics) – This is the first stage of the construction phase. LOD 100 denotes the design and schematic stage. The details produced with this LOD is just basic massing, lines and 3D geometry. This model will give you an idea of how a building structure will look like in a nutshell. This model will not even have door or window details. Architects and Engineers can use this model for energy modeling purposes too. Software like Revit can be used for basic 3D modeling and Ecotect can be used for energy modeling.

LOD 200 (Design Development) – With LOD 200, you can create a presentation model for the client. This presentation model gives an idea of the door window shapes, size, flooring, basic and generic furniture placements etc. The BIM Models exhibit a general design of a building structure. LOD 200 models are an integral part of the Architectural BIM Services which starts with design intent model and can be further upgraded based on different functions.

LOD 300 (Detailed Design and Documentation) – Other phases of BIM starts with the LOD 300. The 3D geometry created with LOD 300 indicates that this model is much more than mere presentation. When a client demands LOD 300 model, it means that he intends to use BIM for construction. Clash detection and BIM coordination, Architectural Construction Drawings, 3D Rendering Services etc. all these construction processes require ample level of detailing. In this model, we can use generic as well as parametric Revit families. These models can be used to extract coordinated shop drawings further used for construction.

LOD 400 (Construction & Fabrication) – These models basically are a level up than LOD 300. These models have shop details, detailed views of components that can be fabricated. The assemblies are with real time details, that help the Engineers and onsite construction labor to proceed ahead with the installation of specific components. In LOD 300 you come to know about the placements but with this the specific details and parts are developed and can be used to fabricate them through CNC machines. tconstruction or fabrication and also facilitates them

LOD 500 (As Built) – This is the last stage of the BIM Modeling phase. The as-built stage covers the updation of the BIM model with the onsite construction updation. This model is further retained for facility management and renovation of the building at a later stage. These models are leveraged to analyze building efficiency once it gets operational. Scan to BIM Services is another BIM discovery that eliminates manual surveying and drawing creation by scanning the building structure

BIM LOD specification has enabled segregation of the whole BIM modeling and design process in various levels. Is has helped in distributing the work load and ease the way for Engineers, Modelers and other authorize professionals.

Source: https://bimforum.org

Benefits of using BIM Modeling from a contractor stand point

BIM stands for Building Information Modeling, a virtual design process that delivers a complete 3D geometry loaded with building data like quantities, material information, Revit families etc. for further construction processes. These details can be utilized to present the aesthetics, functionality and building efficiency overall much before they are constructed. Contractors can take advantage of BIM owing to plenty of other advantages it has to offer. Construction technologies are reinventing themselves year on year with several cloud based software like BIM 360 gaining prominence. These services are providing great opportunity to the contractors to use BIM for the overall construction process. Let us see how virtual construction technology works with the contractors. Adoption of this process is enabling contractors to follow a structured project execution method and project delivery accurate and quicker.

BIM in pre-construction Phase

BIM Modelling is carried out by Architects, Engineers and Contractors to virtually construct the building to understand the overall building functionalities. By working with the Virtual Construction Modeling or “Virtual Design Construction”, contractors can ease their design process and detect design flaws prior to the beginning of the construction process. As we all understand Building Information Modelling works with a collaborative approach and enables every party involved in the design and development process to be in sync with each other. We can achieve

Reduced cost and quick delivery
Accurate results
Design changes
Single Model utilization for all phases

Architects and Contractors are adopting virtual construction modeling for the designing and construction process. This BIM Modelling process nowadays is widely used by contractors to handle complex infrastructure projects too. As we all know Virtual Construction Modelling is much more than just 3D Models and drawings. It gives a great value addition to the entire construction process and brings a simple 2D CAD drawing by adding visual 3d features, building data etc. Information found in the 3D Model generally comes in light only during actual construction. But with the help of BIM Coordination Modelling, lot of critical clashes or interferences that are usually detected during construction is identified during the clash detection process.

Building information modeling facilitates the Contractor by providing a single model with building data that brings all the parties together and reaches an amicable conclusion regarding any design change.

Any construction project is dependent on the ability to work seamlessly within each department. The ability to share, verify and process building data plays a very important role. This is where BIM Modelling comes into play. This process helps in creating a common data sharing tool that helps in the construction process and also after post-construction process. Contractors require complete building data that is usually provided for construction on site. Hence, the contractors would like to receive a 3d model which has got the flexibility to modify and add details as on site. Contractors are also concerned with the after construction stage too. The contractors can also provide any feedback arising during construction, raise change orders and contact the Architects, Engineers and BIM team to directly incorporate changes. Having a smart model helps a contractor in a lot of ways. The contractor can provide As-built modeling services, facility management etc. after the construction is over. The collaborative approach helps all the parties involved in the process with complete building data and project information for all stages.

Once the 3D Model is built with all data and all the processes, this model is handed over to the owner of the building which he can use for the operational management of the building. Any requirement in terms of replacement of components, renovation or retrofit, new design requirements etc. can be easily dealt with in case of an in place BIM Model.

The 3D geometry within the BIM Model, building data and the Revit families depict detailed information such as manufacturer detail, asset tags, locations etc. It gets easier to order the equipment’s in case of any repairs or issues within the building. Since it is a 3d virtual model depicting the building as it would be constructed, it becomes easier to understand the wall penetrations too or interior elements within the wall, ceiling etc.

Apart from contractors, even sub-contractors are an integral part of the entire virtual construction modeling process. Right from BIM Modeling and conducting coordination meetings, they work hand in hand with the contractors. BIM Model is the key information Centre for the entire construction and project team. We can extract Architectural construction drawings, MEP Installation drawings, Revit Families etc. from a single 3d geometrical model and perform constructability reviews, construction scheduling etc. With the help of BIM 360 tool, we can work with real-time changes and updates. Models will be all time updated with all the project progresses and finished items. All the parties are aware of what is going on with the project. Any design changes are communicated uniformly within all parties through BIM 360 tool.

Utilization of Building Information Modeling helps contractors maximize their profitability by working on a turnkey project such as complete installation and facility management services. Building Information Modeling is extremely beneficial to the contractors working turnkey. These services can be more productive with virtual construction modeling. Most of the issues can be resolved by referring to the completed 3D Model. Intricate information of types of equipment can be found within the Revit families. Owners can get a very fair idea of the maintenance cost during the construction and post-construction phase.

One of the key benefits that contractors avail by opting to work with BIM is the integration of the cost and timeline with the building data. Overall results have achieved great boost and results for all the parties involved in the project.

More and more contractors are now getting into turnkey projects and offering BIM Model as a part of their integrated service delivery model. Builders and stakeholders initially did not find it lucrative, however looking at the amount of assistance this provides post construction they have also begun to use this process.

Source: https://www.kiwibox.com

What Interoperability really means in a BIM context?

It has been an interesting week for interoperability in the BIM world. Three of the dominant players have made public statements on their strategy for BIM interoperability. Autodesk and Trimble issued a joint press release announcing anagreement to increase interoperability for customers to gain flexibility throughout the BIM project lifecycle. At the core of the press release was support of IFC and COBie.

Two days later BIM+ published an interview with Bentley Systems CEO Greg Bentley where BIM interoperability were also a key topic. Bentley were less supportive of IFC and COBie as we will see but still had a solution for interoperability in the AEC industry.

In this article we will look at what what interoperability really means in a BIM context. Then we will use select quotes from the press release and the interview to discuss the current state of interoperability in the world of BIM. We will see progress and good signs but we will also see issues, limitations and confusing and provocative statements. At the end we ask if these vendors holding the interoperability banner high are “sailing under false colors” or if they are just doing the best they can with the limitation of the current standards. Read on and see if you share our opinion.

What is interoperability

Before we dive in, let us have a quick refresher on what interoperability is. Lets look at the definition from the AFUL interoperability working group :

Interoperability is a characteristic of a product or system, whose interfaces are completely understood, to work with other products or systems, present or future, in either implementation or access, without any restrictions.

This definition is quite a mouthful. At least we can draw one main conclusion – you cannot have interoperability without open standards. Let us explore further

Interoperability in BIM software

Wikipedia have a separate sub-chapter on software interoperability that are a bit more specific.

With respect to software, the term interoperability is used to describe the capability of different programs to exchange data via a common set of exchange formats, to read and write the same file formats, and to use the same protocols.

One common use case for software interoperability is for the customers freedom to switch from one product to another while keeping the data intact after the transfer. This is especially important for use cases where the data will stay in one system for a long time (e.g. in Computer Aided Facility Management – CAFM systems) to prevent vendor lock-in.

For BIM interoperability there is another just as important driver. In the construction industry where one-off projects teams are assembled across different organisations, disciplines and phases you want the different discipline tools to share information with each other and you want data generated in one phase to be usable without re-entry for the next phase. This is the foundation for openBIM. You cannot have a true openBIM workflow without interoperable software. Interoperability is about freedom to work with the best in any discipline and for them to use the tools they are most comfortable and productive with.

Semantic interoperability and BIM

To communicate with each other systems need to use common data formats and communication protocols. Examples of formats are XML, JSON, SQL, ASCII and Unicode. Examples of protocols are HTTP, TCP, FTP and IMAP. When systems are able to communicate with each other using these standards they exhibit syntactic interoperability.

For BIM tools to work together we need more than just the ability to transfer information. We need the ability to transfer meaning. What is sent must be the same as what is understood. To achieve this both sides must refer to a common information exchange reference model. We need semantic interoperability.

What is not interoperability

The figure above is also taken from the interoperability working group. It is presented under the heading “degrees of interoperability”. However we would argue that the two first categories are not real interoperability. Again we use wikipedia to clarify when a vendor is forced to adapt its system to a dominant system that is not based on Open standards, it is not interoperability but only compatibility.

Plug-ins to BIM tools are common ways of providing such a compatibility solution.

The vendor behind that product can then choose to ignore any forthcoming standards and not co-operate in any standardisation process at all, using its near-monopoly to insist that its product sets the de facto standard by its very market dominance.

The design industry have a long history of dominating vendors trying to corner the market by controlling the de facto standard. We will later see if this is still relevant in the world of BIM

BIM maturity and interoperability

We have covered BIM maturity as described by the BIM levels before BIM level 1 is obviously not interoperability. Here BIM tools are used to automate the generation of design documents but no reusable data is passed on to the other parties in a standard format.

BIM level 2 is mainly about federated models and file based collaboration. The UK based BIM level 2 minimum requirements are requiring a combination of 3D native models and COBie data. As the native formats are not open standards the BIM level 2 mandate do not require real interoperability at this stage.

In our view it is first when you get to level 3 and move beyond just the file based collaboration you get truly integrated interoperable data. By the original definition level 3 would mean a centralised model that all parties are contributing to and benefiting from.

Now that we have some background on what requirements for real BIM interoperability are, let us have a look at the two case studies

Case study 1 : Autodesk and Trimble joint press release

For our first case study we will look at the joint press release from Autodesk and Trimble

To support open industry standards such as Industry Foundation Classes (IFC) and Construction Operations Building Information Exchange (COBie)

This is good news for openBIM and following a trend we have seen lately.

Trimble already have announced this kind of partnership with Nemetschek last year (2015).

Autodesk has also moved towards more actively promoting openBIM interoperability. In example by promoting openBIM at BIM World Paris this year (2016).

So all in all this is good new for the openBIM – buildingSMART community. IFC and COBie are taking steps to becoming the unrivalled open standard for interoperability in the AEC industry.

work together seamlessly through optimized file compatibility across applications

File compatibility is important for level 2 BIM. We are hoping the ambition is also to move beyond this

And what´s that word – compatibility – that´s not interoperability. Let explore the press release further in the next section

Tighter product-to-product integration can enable design and construction professionals to share models, project files and other data between select Autodesk and Trimble solutions

Yep – that´s compatibility for you. This is about two vendors saying their joint customers will get an edge over other players due to a tighter point to point integrations. Or are we misinterpreting this?

Again – the blame for this should not go to the vendors alone. If they want to provide “lossless” data transfers with semantic interoperability the current state of openBIM will only take them so far

The solution for industry interoperability : openBIM needs to evolve along the needs of the industry and vendors should work with standards bodies and “donate” results of these efforts back to the community

accelerate interoperability by exchanging Application Programming Interfaces (APIs) and developer tools to build and market interoperable products

Again it will be interesting to see if this is a compatibility play or interoperability play. This industry is in need of open API´s to support interoperability.

UPDATE : After publishing this article we have come over this article where Jim Lynch of Autodesk confirms these points.

with those types of exchange formats or industry standards, you’re somewhat limited in what you can actually do.

AndToday, those products [Revit and Tekla] do interoperate via IFC, but when you take it to the next level of APIs, you get much stronger and more direct interoperability,

This confirms our point that the press release was a bit misleading. END UPDATE

Case study 2 – Bentley interview

Let´s move on to the Bentley interview and focus on quotes related to interoperability.

Interoperability is now provided though collaborative services that work well with our competitors’ software. You should also give some credit to Autodesk. We have a long-standing interoperability agreement with them.

This just confirms what we have seen. Point to point compatibility integrations are taken for interoperability. And those integrations are not based on open APIs. Bentley are promoting the use of its own i-model format generated by design software plug-ins.

(On IFC and COBie) : they will never go far enough, or be current enough, or be extensive enough to quite achieve a standard of persisting intelligent data

Yes there are limitations in the current implementations. But can they never be fixed? If the industry come together to work to fix the limitations? Again Bentley only see their own format as a viable solution.

Instead of complaining about lack of interoperability there are very practical ways to overcome it, that the internet has led to a strategy for self description. If in the AEC world we say that a lack of standards is holding us back we are making excuses.

Interoperability implies open standards by definition. If you are inventing your own integration layer, hoping it will become a defacto standard you should not call it interoperability.

I can’t think of anything but problems with COBie. …. What would you actually use it for, it’s verbose, it’s limited in terms of virtuosity and as a data exchange mechanism it is almost entirely theoretical as every time the design changes, which is constantly, you would have to re-export the whole COBie

COBie is not about sharing design data each time the design changes. COBie defines data drops related to the transition between each main phase change in the project lifecycle, the main one being handover of as built and operations and maintenance data. Owners capable of utilising models for the operations phase would typically require a combination of native models and openBIM iFC files to transfer the virtuosities of the models.
For the use cases Bentley describes buildingSMART are working on alternative model-view definitions and representations. We totally agree that that work needs to speed up, but attacking COBie for that flaw is really missing the point

So what is Bentleys solution to the interoperability challenge of the industry. Bentley have their own format called I-model. I-models can be created using free plugins to tools both from Bentley (e.g. Microstation) and some other tools (e.g. Revit). The i-models can be viewed in free viewers from Bentley (if you are on the windows platform) or they can be viewed as 3d pdf files (if that is the format the models were published to). The data in the i-models can be accessed via an ODBC database driver that Bentley provides. That means that there are integration possibilities but we would not call it an open standard and therefore not an interoperability solution.

To give some balance to the discussion we trust that Bentley are right when they say that the I-model format have many advantages over the openBIM formats/ standards. The one thing that counts however in interoperability and standardization is market adoption. Have a look at the trend graph below. IFC is definitely on the rise. That is not the case for i-model

Summary

openBIM as defined by buildingSMART is well positioned to become the interoperability framework for the AEC world. To do so however requires buildingSMART and the community to work through some limitations and constantly improve both the standard and the implementations.

Bentley is now the only major BIM player not openly supporting interoperability based on openBIM. At the same time the market is screaming for interoperability between the building and infrastructure domains. buidlingSMART have it on their todo list. Bentley say they have a superior solution…

Then back to our question – are the industry sailing under false colors?
Sailing under false colors is probably a too harsh expression for this. But we do think however that the interoperability term is thrown around a bit too loosely in our industry. Especially in marketing messaging. It is being used to describe point-to point solutions and it is being used to describe integrations based on proprietary formats. We think the industry needs to understand and agree on what interoperability is to make educated decisions based on the messaging from the vendors.

We also strongly hope that our standards will evolve so that compliance with the standard and working in the community is the main message you are promoting, not integration with another vendor.

Source: blog.areo.io/bim-interoperability

7 Reasons Why Transitioning to BIM Makes Sense for Small Firms

The benefits and capabilities of building information modeling in large-scale architectural practices are well known. But is BIM really necessary for smaller firms? Many small firms have been operating using traditional CAD methods for some time now, and switching technologies can seem a daunting task, especially for companies that operate on small budgets and without the specialized personnel of large international firms. But this is 2016 and the economic landscape has changed, with more and more expected from architects all the time. Time is more valuable now than ever. Where BIM software programs were once seen as simply nice to have, their large range of benefits have now made BIM an essential part of the design process. And as the following reasons show, BIM is just as important a tool for small offices as it is for larger ones.

Reason 1: Wow Factor

BIM is such an obvious solution for large projects, as it allows architects, consultants and contractors to work using the same information, that large-scale developers have begun to expect 3D models and multiple perspectives for every project. But many clients that small firms often work with are less familiar with BIM—or even the design process in general. Davey McEathron of Davey McEathron Architecture explains:

“The efficiencies that are built into a BIM program are one of the things we tout when we are in front of a client trying to win that business. When you show a client a 3D model and start spinning it around, it kind of blows their mind.”

Harnessing BIM technology when pitching to clients instills confidence in your work, while exciting them with an accurate visualization of how their project will look.

Reason 2: Shorten Feedback Loops, Save Time

CAD is a drafting program, not a responsive modeling program. This means that when changes need to be made to a drawing set, the architect must go through each drawing to make updates, taking valuable time and increasing the probability of user error. BIM software recognizes changes three-dimensionally, and will update all drawings at the same time, allowing architects to focus on more important duties.

Reason 3: Avoid Outsourcing

For competitions and important projects, computer renderings are an obligatory tool in attracting a client’s attention. Without BIM, creating these images is a headache that many small firms prefer to outsource rather than produce in-house. Yet outsourcing can be expensive, and any miscommunication could result in an imperfect product.

As Geoffrey Tears of Mohle Design explains, it can be difficult to compete when you “have to outsource to get things rendered, versus the bigger firms who are actually making these 3D models and producing information as they go.”

Reason 4: BIM is the Future

While it’s possible today to operate without BIM, widespread adoption and government BIM mandates have made BIM the global industry standard. New productivity updates for BIM programs continue to increase the software’s capabilities, further widening the gap between old and new ways of practicing. Meanwhile, architects will need to keep up with their clients, who will continue to demand more descriptive models and images, expect competency in modern technology, and will be less willing to pay for the hours needed to update drawing sets. Firms using only CAD software may find themselves at a disadvantage.

Reason 5: BIM Can Help Market Your Firm

Image is everything. Attracting new clients means having to tout your firm’s abilities and accomplishments. BIM can help create both the images and the documents needed. “It’s provided us a really fast tool for marketing,” said Tears, “in that we can set up all of our necessary drawings and renderings, or go through and set up a whole new document of purely marketing packages, so that we’ve done all our graphic design in Revit.”

Reason 6: Build Trust and Secure Repeat Clients

The most important thing for most clients is that a project is completed in a timely manner and for around the expected budget. If an architect is able to deliver those things, the client will be more likely to use their services again in future developments. BIM allows architects to more easily create precise, correct construction documents and thus more accurately predict costs.

For Vanessa Bizzell of Bluemouse LTD, making clients happy is about mitigating risk. “Because we’re building in 3D, I have the confidence that the work I put in Autodesk Revit LT will work when we build, and that any problems are sorted out before we get on site. I know my clients don’t always have that confidence; [working with other architects] they have to use contingency plans. But I couldn’t justify taking the risk for them.”

Reason 7: Compete with Larger Firms

Small firms often find themselves competing with much larger firms to win a project. To compete successfully in these situations, small firms need to start on a level playing field. Using BIM software allows fewer people to do a lot more in less time, while demonstrating to the client that despite your smaller size, you’re just as sophisticated as the larger practices they may be considering. Once your drawings sets are in equal standing with your competitors, the actual designs will shine through.

Tears explains how not having BIM can hurt smaller firms:

“One of the big issues for us in getting those bigger jobs — as well as just competing for those jobs — was that it was tougher for our firm to show up with just 2D drawings and space plans and elevations, compared to some of those bigger firms that were competing for the same jobs and would have renderings and walkthroughs. Any bit of information that they needed to take out, they had.”

In our fast-paced world, time is the most valuable asset for an architecture firm. BIM cuts out needless time-wasting work, allowing firms to get the most out of their projects—regardless of size.

Source: https://www.archdaily.com

Building Information Modeling is More than Software

It is 2018, and it should be clear to everyone in the AEC industry that BIM is the future of building, infrastructure design, construction, and maintenance. There are millions of marketing dollars spent by BIM software companies each year trying to convince you that Building Information Modeling can’t happen without their product. They will try to convince you that their product is the “real BIM.” Of course, we live in an open, capitalist society where this behavior is expected. However, if you and your firm are making the move to BIM, this background noise may be concerning… and if it’s not, it should be.

In the first paragraph of Wikipedia’s entry on Building Information Modeling, the statement is made that building information models are files that are “…often but not always in proprietary formats and containing proprietary data…” This is troubling to some, however, understandable, of course. If your BIM software solution becomes inaccessible for any reason, your work is captive. For many, this is unacceptable and prevents them from moving forward to the power of BIM.

The idea of proprietary formats and databases is rooted in the concept of traditional BIM.

This concept goes back to the beginning days of computer science. The concept is that these custom data structures can be optimized to store information formatted in a way that improves access speed, reducing the time needed to load the BIM’s data. While this can be true, it’s not a given – especially when you consider the incredible capabilities of today’s computers. And it is possible that proprietary file formats actually hinder productivity by limiting the way that proprietary BIM solutions work across systems and disciplines.

This lack of good software interoperability is a major obstacle to efficiency and technology adoption. This is more insidious than it might appear at first. As firms resist the move to BIM, they limit their ability to work with other disciplines in the larger AEC workflow. This can limit access to expertise, raise total project costs, and add workflow gaps that can lead to costly rework.

Is there a solution to this problem? Yes, and it’s not what some may believe to be the obvious answer. The first part of a modern, interoperable BIM workflow is based on industry standard, non-proprietary file formats. Then, you’ll want your BIM model data represented in accordance with open, international standards. And you’ll need the ability to transfer BIM data accurately between multiple BIM tools that support all disciplines in this modern BIM workflow.

Source: https://www.archdaily.com

A Brief History of BIM

Building Information Modeling (BIM) is a term that has become ubiquitous in the design and construction fields over the past 20 years, but where did it come from? The story is rich and complex with players from the United States, Western Europe and the Soviet Block competing to create the perfect architectural software solution to disrupt 2-Dimensional CAD workflows.

The benefits of an architectural design model tied to a relational database have proven to be incredibly valuable, with contractors becoming the primary drivers of BIM technology for the first time in 2012.

What exactly is BIM?

The question often arises, for the purposes of this article, BIM software must be capable of representing both the physical and intrinsic properties of a building as an object-oriented model tied to a database . In addition most BIM software now features rendering engines, an optimized feature specific taxonomy and a programming environment to create model components. The user can view and interact with the model in three-dimensional views as well as orthographic two-dimensional plan, sections and elevation views of the model. As the model is developed, all other drawings within the project will be correspondingly adjusted. A Building Information Model could be designed in a software that is not strictly speaking, ‘parametric’ and where all information and geometry is explicitly defined but this would be cumbersome.

A parametric building modeler will allow the user to create constraints such as the height of a horizontal level, which can be tied to the height of specified set of walls and adjusted parametrically, creating a dynamic database model which is tied to geometry. This development answered a need in the architectural industry to be able to change drawings at multiple scales and across fragmented drawing sheets. The amount of hours that are necessary for the production of drawings has decreased steadily over time with the general trend of non-farm labor in the United States since 1964. The improvement in productivity has risen in concert with computer technology which has automated tedious tasks in all disciplines. Although some of the earliest programs for architectural representation used a BIM metaphor, limitations in computer power and awkward user interfaces for BIM platforms contributed to a growth in two-dimensional line drawing programs such as AutoCAD and Bentley Microstation.

The Beginnings

The conceptual underpinnings of the BIM system go back to the earliest days of computing. As early as 1962, Douglas C. Englebart gives us an uncanny vision of the future architect in his paper Augmenting Human Intellect.

“the architect next begins to enter a series of specifications and data–a six-inch slab floor, twelve-inch concrete walls eight feet high within the excavation, and so on. When he has finished, the revised scene appears on the screen. A structure is taking shape. He examines it, adjusts it… These lists grow into an evermore-detailed, interlinked structure, which represents the maturing thought behind the actual design.”

Englebart suggests object based design, parametric manipulation and a relational database; dreams that would become reality several years later. There is a long list of design researchers whose influence is considerable including Herbert Simon, Nicholas Negroponte and Ian McHarg who was developing a parallel track with Geographic Information Systems (GIS). The work of Christopher Alexander would certainly have had an impact as it influenced an early school of object oriented programming computer scientists with Notes on the Synthesis of Form. As thoughtful and robust as these systems were, the conceptual frameworks could not be realized without a graphical interface through which to interact with such a Building Model.

Visualizing the Model

From the roots of the SAGE graphical interface and Ivan Sutherland’s Sketchpad program in 1963, solid modeling programs began to appear building on developments in the computational representation of geometry. The two main methods of displaying and recording shape information that began to appear in the 1970s and 1980s were constructive solid geometry (CSG) and boundary representation(brep). The CSG system uses a series of primitive shapes that can be either solids or voids, so that the shapes can combine and intersect, subtract or combine to create the appearance of more complex shapes. This development is especially important in representing architecture as penetrations and subtractions are common procedures in design, (windows, doors).
The process of design requires a visceral connection to the medium that the designer is working in. This posed another challenge as architects required a way to tell the computer what to do that was less tedious than the punch cards that were used on early computers. The development of light pens, head-mounted displays and various contraptions in the early days of human-computer interaction (HCI) are well documented elsewhere. A rigorous history of HCI from an architectural perspective can be found in Nicholas DeMonchaux’s book, Spacesuit: Fashioning Apollo. The text carves a narrative of the precursors to BIM and CAD technology as they were entwined in the Space Race and Cold War.

Database Building Design

Seeing buildings through the lens of the database contributed to the breakdown of architecture into its constituent components, necessitating a literal taxonomy of a buildings constituent parts. One of the first projects to successfully create a building database was the Building Description System (BDS) which was the first software to describe individual library elements which can be retrieved and added to a model. This program uses a graphical user interface, orthographic and perspective views and a sortable database that allows the user to retrieve information categorically by attributes including material type and supplier. The project was designed by Charles Eastman who was trained as an architect at Berkeley and went on to work in computer science at Carnegie Melon Uniersity. Eastman continues as expert in BIM technology and Professor at the Georgia Tech School of Architecture.

Eastman claims that drawings for construction are inefficient and cause redundancies of one object that is represented at several scales. He also criticizes hardcopy drawings for their tendency to decay over time and fail to represent the building as renovations occur and drawings are not updated. In a moment of prophecy, the notion of automated model review emerges to “check for design regularity” in a 1974 paper.

Eastman concluded that BDS would reduce the cost of design, through ‘drafting and analysis efficiencies’ by more than fifty percent. Eastman’s project was funded by DARPA, the Advanced Research Projects Agency and was written before the age of personal computers, on a PDP-10 computer. Very few architects were ever able to work on the BDS system and its unclear whether any projects were realized using the software. BDS was an experiment that would identify some of the most fundamental problems to be tackled in architectural design over the next fifty years. Eastman’s next project, GLIDE (Graphical Language for Interactive Design) created in 1977 at CMU, exhibited most of the characteristics of a modern BIM platform.

In the early 1980′s there were several systems developed in England that gained traction and were applied to constructed projects. These include GDS, EdCAAD, Cedar, RUCAPS, Sonata and Reflex. The RUCAPS software System developed by GMW Computers in 1986 was the first program to use the concept of temporal phasing of construction processes and was used to assist in the phased construction of Heathrow Airport’s Terminal three (Laiserin – History of BIM). The founding of the Center for Integrated Facility Engineering (CIFE) at Stanford in 1988 by Paul Teicholz marks another landmark in the development of BIM as this created a wellspring of PhD students and industry collaborations to further the development of ‘four-dimensional’ building models with time attributes for construction. This marks an important point where two trends in the development of BIM technology would split and develop over the next two decades. On one side, the development of specialized tools for multiple disciplines to serve the construction industry and improve efficiency in construction. On the other side is the treatment of the BIM model as a prototype that could be tested and simulated against performance criteria.

A later but prominent example of a simulation tool that gave feedback and ‘suggested’ solutions based on a model is the Building Design Advisor, developed at Lawrence Berkeley National Lab beginning in 1993. This software utilizes an object model of a building and its context to perform simulations. This program was one of the first to integrate graphical analysis and simulations to provide information about how the project might perform given alternative conditions regarding the projects orientation, geometry, material properties and building systems. The program also includes basic optimization assistants to make decisions based on a range of criteria which are stored in sets called ‘Solutions’.

“The input on the left generates the stairs on the right that can be adjusted parametrically. Charles Eastman’s GLIDE was one of the first programs to incorporate most of the major features present in BIM software today.” Image via Charles Eastman’s paper “GLIDE.”

Virtual Building

While the developments were happening rapidly in the United States, the Soviet Block had two programming geniuses who would end up defining the BIM market as it is known today. Leonid Raiz and Gábor Bojár would go on to be the respective co-founder and founder of Revit and ArchiCAD. ArchiCAD developed in 1982 in Budapest, Hungary by Gábor Bojár, a physicist who rebelled against the communist government and began a private company. Gábor wrote the initial lines of code by pawning his wife’s jewelry and smuggling Apple Computers through the Iron Curtain (Story). Using similar technology as the Building Description System, the software Radar CH was released in 1984 for the Apple Lisa Operating System. This later became ArchiCAD, which makes ArchiCAD the first BIMsoftware that was made available on a personal computer.

The software was slow to start as Bojár had to struggle with a unfriendly business climate and the limitations of personal computer software, so ArchiCAD was not used on large scale projects until much later. ArchiCAD has made substantial gains in user base from 2007-2011, mainly as a tool for developing residential and small commercial projects in Europe. Recent improvements have made ArchiCAD a major player in the market though fundamental issues such as a lack of a phasing component and a complicated (but flexible) programming environment for its family components using GDL (Geometric Description Language) To date, Graphisoft claims that more than 1,000,000 projects worldwide have been designed using ArchiCAD.

Not long after Graphisoft began to sell the first seats of Radar CH, Parametric Technology Corporation (PTC) was founded in 1985 and released the first version of Pro/ENGINEER in 1988. This is a mechanical CAD program that is utilizes a constraint based parametric modeling engine. Equipped with the knowledge of working on Pro/ENGINEER, Irwin Jungreis and Leonid Raiz split from PTC and started their own software company called Charles River Software in Cambridge, MA.

The two wanted to create an architectural version of the software that could handle more complex projects than ArchiCAD. They hired David Conant as their first employee, who is a trained architect and designed the initial interface which lasted for nine releases. By 2000 the company had developed a program called ‘Revit’, a made up word that is meant to imply revision and speed, which was written in C++ and utilized a parametric change engine, made possible through object oriented programming. In 2002, Autodesk purchased the company and began to heavily promote the software in competition with its own object-based software ‘Architectural Desktop’.

Revit revolutionized the world of Building Information Modeling by creating a platform that utilized a visual programming environment for creating parametric families and allowing for a time attribute to be added to a component to allow a ‘fourth-dimension’ of time to be associated with the building model. This enables contractors to generate construction schedules based on the BIM models and simulate the construction process. One of the earliest projects to use Revit for design and construction scheduling was the Freedom Tower project in Manhattan. This project was completed in a series of separated but linked BIM models which were tied to schedules to provide real-time cost estimation and material quantities. Though the construction schedule of the Freedom Tower has been racked with political issues, improvements in coordination and efficiency on the construction site catalyzed the development of integrated software that could be used to view and interact with architects, engineers and contractors models in overlay simultaneously.

“This screenshot from Radar CH (later ArchiCAD) shows how far BIM modeling capabilities had developed by 1984, the first major BIM release on a personal computer.” Image via Graphisoft

Towards a Collaborative Architecture

There has been a trend towards the compositing of architectural files with those of engineers who create the systems to support them which has become more prevalent within the past seven years as Autodesk has released versions of Revit specifically for Structural and Mechanical engineers. This increased collaboration has had impacts on the larger industry including a movement away from design-bid-build contracts towards integrated project delivery where many disciplines typically work on a mutually accessible set of BIM models that are updated in varying degrees of frequency. A central file takes an object and applies an attribute of ownership so that a user who is working on a given project can view all objects but can only change those that they have checked out of a ‘workset’. This feature released in Revit 6 in 2004, enables large teams of architects and engineers to work on one integrated model, a form of collaborative software. There are now several firms working towards visualization of BIM models in the field using augmented reality.

A broad variety of programs used by architects and engineers makes collaboration difficult. Varying file formats lose fidelity as they move across platforms, especially BIM models as the information is hierarchical and specific. To combat this inefficiency the International Foundation Class (IFC) file format was developed in 1995 and has continued to adapt to allow the exchange of data from one BIM program to another. This effort has been augmented by the development of viewing software such as Navisworks which is solely designed to coordinate across varying file formats. Navisworks allows for data collection, construction simulation and clash detection and is used by most major contractors in the US today.

Following in the footsteps of the Building Design Advisor, simulation programs such as Ecotect, Energy Plus, IES and Green Building Studio allow the BIM model to be imported directly and results to be gathered from simulations. In some cases there are simulations that are built directly into the base software, this method of visualization for design iteration has been introduced to Autodesk’s Vasari, a stand alone beta program similar to the Revit Conceptual Modeling Environment where solar studies and insolation levels can be calculated using weather data similar to the Ecotect package. Autodesk, through their growth and acquisition of a broad variety of software related to BIM have contributed to the expansion of what is possible from analysis of a model. In late November 2012, the development of formit, an application that allows the conceptual beginnings of a BIM model to be started on a mobile device is a leap for the company.

Contemporary Practice and Design Academics

Some have taken a negative stance on BIM and parametrics as they assume so much about the design process and limit any work produced to the user’s knowledge of the program. This can enable a novice designer who has learned how to perform basic commands to become an incredibly prolific producer while a highly educated and experienced architect can be crippled from inexperience with a programs interface or underlying concepts. This creates a potential for a generational break line that becomes more harsh as a new technology gains market parity.

Some BIM platforms that have a small market share but have made big impacts on the world of design include Generative Components (GC), developed by Bentley Systems in 2003. The GC system is focused on parametric flexibility and sculpting geometry and supports NURBS surfaces. The interface hinges on a node-based scripting environment that is similar to Grasshopper to generate forms. Digital Project is a similar program was developed by Gehry Technologies around 2006 based on CATIA, a design program (and one of the first CAD programs) that was developed as an in house project by Dessault systems, a French airplane manufacturer. These two platforms have spawned something of a revolution in design as the power to iterate and transform has resulted in especially complex and provocative architectural forms.

Patrick Schumacher has coined the movement of parametric building models in architecture, specifically those which allow for NURBS surfaces and scripting environments as ‘parametricism’ in his 2008 ‘Parametricist Manifesto’.

“The current stage of advancement within parametricism relates as much to the continuous advancement of the attendant computational design technologies as it is due to the designer’s realization of the unique formal and organizational opportunities that are afforded. Parametricism can only exist via sophisticated parametric techniques. Finally, computationally advanced design techniques like scripting (in Mel-script or Rhino-script) and parametric modeling (with tools like GC or DP) are becoming a pervasive reality. Today it is impossible to compete within the contemporary avant-garde scene without mastering these techniques.”

Since these techniques have become increasingly complex there has become a component of architectural schools which is specified to train in specific software. A student with knowledge of only one type of software platform may well be trained to design according to the biases of the programs that they are using to represent their ideas. Software performs useful tasks by breaking down a procedure into a set of actions that have been explicitly designed by a programmer. The programmer takes an idea of what is commonsense (Sack 14) and simulates a workflow using tools available to them to create an idealized goal. In the case of BIM tools, the building is represented as components including walls, roofs, floors, windows, columns, etc. These components have pre-defined rules or constraints which help them perform their respective tasks.

BIM platforms typically represent walls as objects with layers, these layers are defined in terms of the depth and height of a wall and are extruded along the length of a line. The program then has the ability to calculate the volume of material contained within the wall assembly and to create wall sections and details easily. This type of workflow is based on the existing building stock and common industry standards and therefore a project which is produced in a BIM platform which emphasizes these tools is likely to reinforce existing paradigms rather than develop new ones. Additionally, the programmers who worked on the early BIM platforms often did not have a background in architecture but employed hybrid architect/programmers who contributed to the development of the programs. One notable exception I have found to this is the work of Charles Eastman who received a Masters of Architecture from Berkeley before working on the Building Description System. The roots of the major BIM platforms that are in use today have been developed by programmers with the peripheral input of hybrid programmer/architects and a global user base who contributes to the development of the software via ‘wish lists’ or online forums where grievances can be aired about a product workflow. The grievances typically result in new features and build upon the existing interface.

Though the general concept and technology behind BIM is approaching its thirtieth anniversary, the industry has only begun to realize the potential benefits of Building Information Models. As we reach a point where a majority of buildings are being crafted digitally, an existing building marketplace where building materials and structural components can be bought and sold locally will emerge. Sustainable design practices reinforce an attitude of designing for disassembly and a marketplace of these parts is essential. Trends in Human Computer Interaction, Augmented Reality, Cloud Computing, Generative Design and Virtual Design and Construction continue to rapidly influence the development of BIM. Looking back at the past it is easier to realize that the present moment is an exciting time for designers and programmers in this evolving industry.

The World’s 18 Strangest Dams

Whether its builder is a beaver or a person, a dam is always used for the same purpose: to manage, direct and prevent water flow. There an estimated 845,000 dams in the world; here are our picks for the 18 strangest.

Three Gorges Dam

Where: Sandouping, China–Yangtze River

Why It’s Unique: China’s Three Gorges Dam is not only the world’s largest hydroelectric dam, it’s also the world’s single largest source of electricity. The construction of the dam has been convoluted: Preliminary plans began as far back at 1932 but construction but didn’t start until late 1994; the dam isn’t scheduled to be completely finished until 2011. The structure’s estimated life is as short as 70 years; that was deemed long enough to justify the displacement of 1.24 million people.

Itaipu Dam

Where: On the border of Brazil and Paraguay–Parana River

Why It’s Unique: The Itaipu Dam, a partnership between Brazil and Paraguay, generated over 90,000 gigawatt hours of power in 2000—then a world record for hydroelectric generation. With a height of more than 196 meters, the dam stands as tall as a 65-story building. Its construction used enough steel to build 380 Eiffel Towers, along with 12.3 million cubic meters of concrete.

Guri Dam

Where: Bolivar State, Venezuela–Caroni River

Why It’s Unique: The Guri Dam in Venezuela not only boasts sky-high walls and powerful generators, it also has artistic flair. Artist Carlos Cruz Diez decorated one of the plant’s machine rooms in mind-bending pattern of colorful vertical bars, while Alejandro Otero built an enormous rotating kinetic sculpture nearby. The dam produces the energy equivalent of approximately 300,000 barrels of oil per day.

Grand Coulee Dam

Where:Grand Coulee, Washington–Columbia River

Why It’s Unique: Washington state’s Grand Coulee Dam is the largest in the United States. Nearly a mile long and 503 meters wide, its base area is large enough to hold all the pyramids of Giza. At 115 meters high, the dam is more than twice the height of Niagara Falls. The dam also has a memorable role in folk music history—a governmental energy organization commissioned Woody Guthrie to write songs about the dam in the early 1940s, including “Roll On, Columbia, Roll On” and “Grand Coulee Dam.”

Sayano-Shushenskaya Dam

Where: Khakassia, Russia–Yenisei River

Why It’s Unique: Russia’s Sayano-Shushenskaya Dam may not hold any records for its electricity generation, but other dams are no match for its sheer strength—the structure’s stated ability to withstand 8.0-magnitude earthquakes has earned it a spot in the Guinness Book of World Records. Still, not even the world’s strongest dam is immune to problems—a 2009 accident in which a turbine exploded resulted in the deaths of 75 people and 40 tons of oil spilled into the river.

Krasnoyarsk Dam

Where: Divnogorsk, Russia–Yenisey River

Why It’s Unique: Although the Krasnoyarsk dam has operated without the notoriety of its Russian neighbor, this concrete gravity dam has troubles of its own. The plant and its reservoir have apparently wrought changes on the local climate, causing the area to experience warmer and more humid weather conditions than the norm, and reducing ice cover in the area, which is in Siberia. Russia shows off the engineering feat on its 10-ruble bill.

Robert-Bourassa Dam

Where: Quebec, Canada–La Grande River

Why It’s Unique: Situated over Canada’s La Grande River, the Robert-Bourassa dam reaches 140 meters below the surface, making it the world’s largest underground plant. The dam’s centerpiece is a unique “giant’s staircase”—each step is the size of two football fields—that sweeps water downward.

Sand Dams

Where: Kenya

Why It’s Unique: Since 1995, Kenya has constructed more than 500 sand dams, which are usually about 50 meters long and 2 to 4 meters high. Unlike larger dams, which usually are used for hydroelectric power, these smaller structures are designed to store water during the wet season so dry communities have a water reservoir when the rain stops. These dams, which store water buried in silt, do a better job than surface water dams of keeping water from evaporating and maintaining water quality.

Redridge Steel Dam

Where: Redridge, Michigan–Salmon Trout River

Why It’s Unique: Located in Houghton County, Mich., this flat slab buttress dam is one of only three steel dams in the United States. Built in 1894, the dam’s spillway broke in 1941 and was partially repaired in 2001.

Timber Dams

Where: Japan

Why It’s Unique: To limit carbon dioxide emissions from steel and concrete dam construction, northern Japan’s Akita Prefecture started a project to build small-scale dams out of the country’s abundant supply of cedar. The dams serve mainly to minimize the effects of landslides and mud flows in the mountains.

Inguri Dam

Where: Jvari, Georgia–Inguri River

Why It’s Unique: At 892 feet in height, the Inguri Dam is the world’s tallest concrete arch dam. Completed in 1978, it was repaired in 1999 at a cost of 116 million euros.

New Cornelia Mine Tailings Dam

Where: New Cornelia Mine Tailings Dam

Why It’s Unique: In terms of sheer volume, the 7.4 billion cubic foot New Cornelia MineTailings Dam is the country’s largest dam structure. But this dam isn’t used for water—it’s used for mining. Mine tailings (loose collections of crushed rock left over from the mining process) were dumped here before the mine was shut down in 1983.

Syncrude Tailings Dam

Alberta, Canada

The Syncrude Tailings Dam holds the highest volume of material of any dam in the world: 540,000,000 cubic meters. This dam holds tailings from oil sands extraction; 500,000 tons of tailings are produced each day.

Verzasca Dam

Where: Ticino, Switzerland

Why It’s Unique: The Verzasca Dam, completed in 1965, is renowned for its beauty and its slender concrete arch. The design used less concrete than comparable dams, resulting in lower construction costs. When its reservoir was filled, small earthquakes were triggered.

Santee Cooper Dam System

Where: Pinopolis, South Carolina—Santee River

Why It’s Unique: Built to create jobs in the region during the Great Depression, the Santee Cooper Dam system boasts a reservoir area of 186,000 acres. The dam system, 42 miles in total, survived the third worst earthquake in U.S. history and was subsequently redesigned and stabilized for future quakes. The Pinopolis Dam, which is part of the Santee Cooper system, has the highest single-lift lock in the world for raising and lowering boats between different levels of water.

Roosevelt Dam

Where: Phoenix, Arizona—Salt River

Why It’s Unique: Italian stonemasons crafted this dam, hand-cutting all the stones for the project. In recent years, the dam’s height was raised 23 meters to increase water storage space by 20 percent, and it was completely resurfaced in concrete, changing its appearance.

Chalk Hills Dam

Where: On the Border of Wisconsin and Michigan—Menominee River

Why It’s Unique: The power house connected to this dam resembles a cathedral, complete with stained-glass windows celebrating the engineers and bankers involved in the original construction, and small multi-colored terrazzo tile. The structure was completed in 1927.

World’s Largest Beaver Dam

Where: Wood Buffalo National Park—Alberta, Canada

Why It’s Unique: Google Earth found the largest beaver dam in Alberta, Canada at 850 meters long–the closest size relative exists in Montana at 652 meters. Viewers think two beaver families constructed this massive piece of architecture, which contains two separate beaver lodges inside. The entire dam is surrounded by wetlands, common of more sizable beaver creations.

Choice of site and type of dam

Dam types can be classified in different categories according to the material used in construction and how they withstand the thrust of water:

homogeneous drained earthfill dams, either zoned or with a man-made impervious element;
gravity dams, whether concrete or RCC;
arch dams;
and buttress or multiple arch dams (not dealt with here).

Fill dams are flexible structures while the other types are rigid.The main parameters to be taken into account in choosing a dam site and type are the following:

topography and inflow in the catchment area;
morphology of the river valley;
geological and geotechnical conditions;
climate and flood regime.

In many cases, after consideration of all these aspects, several types of dams will remain potential candidates. Economic considerations are then applied to rank the available alternatives.

1. TOPOGRAPHY AND INFLOW IN THE CATCHMENT AREA

If we ignore the case of lakes for recreational purposes and small dams for hydroelectric power generation, reservoir storage is the main factor influencing the entire dam design. The objective is in fact to have a volume of water available for increasing dry weather river flow, irrigation or drinking-water supply, or free storage capacity to attenuate flooding.

The first task therefore consists in calculating the volume of water that can be stored in a basin, possibly at several different sites. A first approximation can be achieved using a 1/25 000 scale map with contour lines every 5 or 10 metres, except for reservoirs with storage of several tens of thousand cubic metres. The second task will then be to check whether conditions in the catchment area are such that the reservoir will be filled and to calculate the risk of shortfall.

2. MORPHOLOGY OF THE RIVER VALLEY

A dam is by nature linked to an environment. The morphology of the river valley therefore plays a vital role in the choice of a dam site and the most suitable type of dam.

Of course, the ideal and most economical location will be a narrow site where the valley widens upstream of the future dam, provided that the dam abutments are sound (i.e. a narrowing with no zones prone to rockfall or landslide).

Such a site is rarely found, either because the natural structure of a valley does not offer any point of narrowing or because the choice of the site is not solely dependent on engineering considerations.

As a first approach, a wide valley will be more suitable for construction of a fill dam.

A narrow site will be suitable for a gravity dam as well, and a very narrow site will be suitable for an arch. In every case, of course, provided that the foundation is acceptable.

3. GEOLOGY AND FOUNDATION CONDITIONS

The nature, strength, thickness, dip, jointing and permeability of the geological foundations at the site are a set of often decisive factors in selection of the dam type.

ROCK FOUNDATIONS

Except for severely jointed rock or rock with very mediocre characteristics, rock foundations are suitable for construction of any type of dam, provided that suitable measures are taken to strip off severely weathered materials and, if necessary, treat the foundation by grouting. Fill dams will always be suitable. For the other types, requirements are more severe for RCC, still more for conventional concrete, and finally most stringent for arch dams. The most important aspect is cracking (faults, joints, schistosity).

GRAVEL FOUNDATIONS

Provided that they are sufficiently compacted, gravel foundations are generally suitable for earth or rockfill dams, at least in terms of mechanical strength. Leakage must be controlled by suitable impervious barriers and drainage systems. In practice however, this type of foundation essentially is found on rivers with high flows. The dam must

therefore be able to discharge high floods, which precludes earthfill dams. Very small concrete dams may also be suitable provided precautions are taken with leaks and seepage (risk of piping) and with differential settlement.

SANDY-SILT FOUNDATIONS

Silt or fine sand foundations can be suitable for construction of earthfill dams, and even, in exceptional cases, for very small concrete gravity dams provided strict precautions are taken.

CLAY FOUNDATIONS

Clay foundations almost automatically impose the choice of a fill dam with slopes that are compatible with the mechanical characteristics of the geological formations.

4. AVAILABLE MATERIALS

Availability, on the site or near it, of suitable materials to build the dam has a considerable influence and one that is often decisive in choosing the type of dam:

soil that can be used for earthfill,
rock for rockfill or slope protection (rip-rap),
concrete aggregate (alluvial or crushed materials),
cementitious materials (cement, flyash, etc.).

If it is possible to extract the materials from the reservoir itself, reservoir storage can be increased. This also usually keeps the cost of transport and restoring borrow areas to a minimum.

As a general rule, if silty or clay soil of satisfactory quality (fines content, plasticity, condition) and quantity (1.5 times or twice the volume of fill required) is available, a dam construction alternative using homogeneous earthfill or quarry-sorted materials – setting aside the coarsest materials for the downstream shoulder – will be the most economical provided that the flood flows to be discharged are moderate.

If only a limited quantity of impermeable materials, and coarse or rockfill materials as well, is available, the possibility of a zoned earthfill dam or a rockfill dam with a watertight core can be considered. The disadvantage of this alternative is placement in zones, which is all the more complicated when the site is narrow, hindering movement of the machinery.

If only coarse materials are available, they can be used to build a homogeneous embankment with a watertight diaphragm wall built in the centre of the dam, by grouting after the fill has been placed or by an upstream watertight structure (concrete or bituminous concrete facing).

If only rockfill is available, a compacted rockfill dam with external watertight structure (geomembrane, hydraulic concrete or bituminous concrete facing) on the upstream face, will be suitable. A concrete alternative, especially RCC, can also prove to be competitive provided the foundation is good enough (rock or compact ground) with no need for excessive excavation.

5. FLOODS AND FLOOD DISCHARGE STRUCTURES

The cost of flood discharge structures depends on the hydrological characteristics of

the catchment area.

When the catchment area is large and floods are likely to be high, it may be advantageous to combine the dam and spillway functions and build an overspill dam.

On the other hand, if the spillway can be kept small, a fill dam will be preferred if all other conditions are equal.

When construction of the spillway would require significant excavation, the possibility of using the excavated materials will also be a factor in favour of building a fill dam.

When a tunnel is required for temporary diversion of the river during the work, it can usefully be incorporated into the flood discharge structures, if necessary increasing its cross-section slightly.

The choice of an RCC dam can be attractive if it is a means of shortening construction lead time and removing the risk of damage from flooding of the site before construction is complete, a risk that, with any other alternative, would mean building costly diversion or protection structures.

6. ECONOMIC CRITERIA

In many cases, the considerations set out above will be sufficient to select several types of dam as potential alternatives. For example, if the foundation is rock, loose materials are available near the site and flood flows are high, the choice will be between an RCC dam and an earthfill dam with a costly spillway.

The studies must then be pursued for these two types of dam, taking care to refine the cost estimates as the studies progress. As soon as one of the dam types seems significantly more economical, it is preferable to waste no further time on the other option.

CONCLUSIONS ON SELECTING A TYPE OF DAM

The choice of a type of dam is imposed by natural conditions in many cases, with no need for in-depth investigations. For example, if the rock substratum is at a depth of more than 5 metres, the only reasonable alternative will be a fill dam, at least for any project less than 25 metres high. In some regions, the geological context is such that

only one type of dam is usually built.

In other cases, the choice of dam type will be a compromise between different aspects – type of foundation, availability of materials in the vicinity, hydrology – to arrive at the best option economically speaking.

However, it is always an advantage to make a decision as quickly as possible, as a rule after the feasibility studies.