BIM+blockchain Makes Urban Construction Smarter

In this article, we talk about the combination and application of blockchain and the construction industry.

Before starting the text, let me first explain the concept of BIM.

BIM ( ) Building Information Modeling. The U.S. National BIM Standard explains BIM as follows:

(1) Digitally express the physical and functional characteristics of a facility.

(2) Share knowledge resources.

(3) The process of sharing facility-related information provides a reliable basis for all countermeasures throughout the facility's entire life cycle.

(4) At different stages of the construction project, each participant embeds, extracts, updates and modifies information in the information model to support and reflect the collaborative work of their respective responsibilities.

1. The importance of the construction industry to the national economy

The construction industry is one of the largest industries in the world today and will remain the main driving force for world economic growth in the future.

The construction industry occupies an important position in our country's national economy. According to data from the National Bureau of Statistics, my country's GDP in 2020 was 101 trillion yuan, of which the total output value of the construction industry was 26 trillion yuan, accounting for more than 25%.

Construction is an ancient industry. As early as more than 2,000 years ago, ancient people built magnificent projects such as the Great Wall and the pyramids of ancient Egypt. However, so far, the overall management level and efficiency of the construction industry are still very low. The main reasons can be roughly summarized into the following five points:

1) One-time items;

2) The organization is loose and temporary;

3) Decentralized management;

4) Multi-party cooperation, low efficiency;

5) Non-standardization and de-industrialization of the production process.

The problems caused by the above reasons are also obvious:

1) Lack of trust. Due to the one-time nature of the project, the temporary nature of the organization, and the multi-party nature of the cooperation, a lack of trust is inevitable.

2) Low efficiency. Due to the loose and temporary organization, non-standardized and non-industrialized production process, high consumption and low efficiency, the average profit level of construction companies in the entire construction industry is only about 3%.

3) Weak risk controllability. Due to the lack of a systematic and standardized management system and fragmented management, project delays, design changes, and cost claims are inevitable for almost every project.

2. The significance of BIM digitalization in the construction industry

Domestic building informatization has gone through three stages and is currently in the third stage:

The first stage: design informatization. The “Drawing Board” project in the 1990s promoted the popularization of domestic CAD technology applications;

The second stage: enterprise information management. In 2005, computer-aided management problem solving was implemented to realize informatization of project and enterprise management;

The third stage: full life cycle informatization. In 2015, the application of BIM technology assisted the integration of information throughout the entire life cycle of the construction industry.

2.1 Why should BIM be implemented in the construction field?

The Ministry of Housing and Urban-Rural Development gave a detailed explanation of the significance of BIM application in the "Notice of the Ministry of Housing and Urban-Rural Development on Issuing Guiding Opinions on Promoting the Application of Building Information Models." The guidance points out that BIM should provide technical support for industrial chain connection, industrialized construction, and prosperous architectural creation. . In other words, BIM is the technical foundation for industrial transformation in the construction industry.

2.2 What exactly can BIM do?

1) Based on the same multi-dimensional building information model, data sharing among all participants in the whole life cycle of the building is realized;

2) Support analysis, inspection and simulation of engineering environment, energy consumption, economy, quality, safety, etc.;

3) Provide a basis for program optimization and scientific decision-making throughout the project process;

4) Support collaborative work, virtual construction and refined project management of various majors.

2.3 The significance of construction industrialization

1) Industrialized production materials and prefabricated construction methods make it easier to form a standardized system and ensure product quality;

2) Most components of prefabricated buildings are completed in the factory, and the overall delivery is 30% to 50% faster than traditional buildings;

3) Prefabricated construction sites mainly use dry methods, which can effectively reduce energy consumption and environmental pollution, and are low-carbon and environmentally friendly;

4) Prefabricated buildings can also be reused due to their detachable characteristics;

5) At present, the space for cost reduction of prefabricated buildings is much higher than that of traditional buildings. Post-operation and maintenance costs are lower, and the entire life cycle has greater cost advantages.

The transformation of construction industrialization has become a national strategy

In recent years, the Ministry of Housing and Urban-Rural Development and other departments have successively introduced a number of important policies to promote industrialization, digitalization, green construction, and intelligent construction in the construction industry.

In March 2021, the State Council issued the "14th Five-Year Plan Outline and Long-term Goals for 2035", which clearly proposed the development goals of developing intelligent buildings, promoting green building materials, prefabricated buildings and steel structure residences, and building low-carbon cities.

2.4 The importance of BIM digitalization in the construction industry

Vigorously developing construction industrialization, digitalization, and intelligent upgrading, increasing the application of intelligent construction in all aspects of engineering construction, and realizing the transformation and upgrading of the construction industry have been the strategic goals of the construction industry and the country in the past 10 years. 20 years. Therefore, BIM digital technology will play a fundamental and important role in the transformation and upgrading of the construction industry.

3. How does blockchain technology + BIM realize smart construction?

The transformation direction of construction industrialization is standardization + factoryization + assembly. BIM solves the digital integration and visualization issues in this process.

Although BIM is an indispensable technology in the industrial transformation process of the construction industry, it cannot effectively solve problems such as trust and efficiency among collaborators in production relationships and fragmented management under complex systems.

Solving trust, collaboration, efficiency, and fragmented management under complex systems are the natural advantages of blockchain technology and can well complement BIM technology.

Therefore we say: industrial production (BIM support) + digital collaboration (blockchain support) + big data decision-making (AI technology) = intelligent construction

We divide the building life cycle into three stages: planning and design, construction, and operation and maintenance to illustrate.

3.1 Planning and design stage

Cross-department collaborative approval will be the main scenario for the application of blockchain technology.

The planning and design stage is characterized by multiple administrative supervision roles and coordinated approval procedures. The decentralized nature of blockchain technology is just right for such a scenario, and can greatly improve the efficiency of collaborative approval (many governments have already begun piloting blockchain government approval systems).

We assume that the regulatory units in the planning and design stage include the National Development and Reform Commission, land and resources, transportation, housing and urban-rural construction, water conservancy, etc. In addition, relevant units include construction units, planning and design departments, etc. and other consulting units. They all have their own nodes on the blockchain, and each has its own node. It has its own information management system.

When the consulting unit creates the first-stage BIM conceptual model (for example, applicable to project proposals), it loads various economic indicators such as GIS information, scale, land occupation, cost, etc., and uploads the model data to the blockchain.

After the BIM conceptual model and project proposal are confirmed by the construction unit, the construction unit will initiate the approval process with the National Development and Reform Commission, and the blockchain smart contract will automatically start all review processes.

The National Development and Reform Commission accesses the BIM conceptual model on the blockchain through a key, loads the BIM model and GIS information of surrounding infrastructure when necessary, analyzes whether the project complies with the urban development master plan and the feasibility of the project, and uploads the approval results to the block Chain, the smart contract automatically sends the data file of the approval result back to the construction unit.

Similarly, the construction unit starts the land pre-examination related procedures, activates the smart contract, and the land department accesses the BIM land occupation model on the blockchain through the key, conducts review, and uploads the approval results to the blockchain, and the smart contract will approve the result data The documents are sent back to the construction unit.

At the same time, any regulatory department can use the key to verify the authenticity of the approval results of the National Development and Reform Commission, Land and Resources and other departments.

As the subsequent feasibility study, preliminary design, and construction drawing design continue to improve the model, the National Development and Reform Commission, land, transportation, housing and construction and other industry regulatory authorities can retrieve the BIM model data of the project on the blockchain for real-time monitoring at any time by pressing a button. Whether the project was designed illegally and constructed illegally.

All approval processes run automatically online, but are no longer based on a centralized platform, but on decentralized blockchain technology, which can effectively reduce collaboration costs, improve collaboration efficiency, and ensure data privacy and security. .

3.2 Construction stage

Similarly, we assume that third-party consulting agencies such as construction units and supervision units also have their own blockchain nodes and their own information systems. They can then all access the project’s BIM model on the blockchain via the key. data.

We simply divide the construction process into planning, procurement, production, acceptance, and payment. And it is assumed that the model corresponds one-to-one with the WBS decomposition structure in the construction stage.

· Planning links:

Contractors can develop plans through a series of software or the domestic Glodon Zebra, and import the plan data files into the BIM model on the blockchain. The BIM model will have 4D progress visualization properties (e.g. series display). Data can also include resources, funding and other initiatives. All participants can conduct project management simultaneously based on the BIM model.

· Purchasing link:

The construction industry has a highly fragmented and complex supply chain system. Cooperation between suppliers and contractors may be temporary or one-off, making trust difficult to build and collaboration inefficient.

Let’s first talk about how blockchain solves the trust problem in transactions.

Blockchain uses smart contracts to complete transactions. For example, for the buyer, before the transaction, the smart contract first detects whether the balance (or bank credit or guarantee limit) of the buyer's digital wallet (central bank digital renminbi) meets the transaction target, and if so, locks it. When the buyer accepts and signs for the seller's goods, the smart contract automatically transfers the locked digital renminbi peer-to-peer to the seller's digital wallet.

Therefore, what blockchain solves is not the problem of mutual trust between buyers and sellers, but trust is no longer a problem.

In construction projects, sand and gravel are used in large amounts, purchased frequently, and from scattered sources. They are among the most difficult materials to control in the construction materials supply chain.

Let’s assume the contractor installed cameras in the silo. The contractor's procurement system detects through cameras that the remaining material in the silo is below a predetermined threshold (computer vision recognition technology), and the system calls planning data (data imported into the BIM model) to discover future usage when demand is greater than the total silo capacity. , the smart contract will be activated to automatically complete sand and gravel orders and even select the lowest price from multiple suppliers.

Sand and gravel suppliers do not need to join any system. They only need to create their own account on the blockchain node to complete automated transaction collaboration with contractors.

During the transportation process, the supplier uploads the GPS location of the transportation vehicle or ship to the blockchain in real time through IoT hardware. The contractor's procurement system can track the location of goods in real time via the key. The system can determine whether the material delivery time is correct. Analyze the impact on the production schedule (search algorithm) so that the smart contract can be restarted for repairs.

The purchase batch and arrival time of each batch of materials can be written into the corresponding location of the BIM model and written into the blockchain ledger. The smart contract will remind the supervisory unit to organize acceptance or testing inspection work based on the batch of materials arriving at the site.

This system can free project managers from complex orders, inquiries, and accounting processing, so they can better devote themselves to more important things.

· Production Process:

The production process is inevitably inseparable from people and equipment.

The inevitable result of industrialization is the improvement of efficiency and quality. The process behavior quality of people and equipment will determine the formation process of product quality.

Therefore, the past result-oriented construction process management must turn to industrialized process-oriented construction management. Then which teams will produce each sub-project, and measure the construction mix parameters of each set of concrete in real time (Internet of Things hardware) monitor and write the corresponding location of the BIM model, and at the same time write these data into the blockchain ledger and save it permanently. Cannot be tampered with. All data in the production process should be authentic and credible.

We assume that large structures are installed using lifting equipment. We also assume that if it is not suitable for lifting operations in heavy rain or strong winds exceeding level 6, then the lifting equipment will sense this extreme state through IoT hardware (or network communication). The blockchain smart contract will remind on-site managers to restore the equipment to a safe state until the dangerous state is resolved.

The fuel consumption and electricity consumption of each equipment during the production process will be monitored through IoT hardware, and this data will be written to the blockchain ledger.

Blockchain smart contracts automatically calculate carbon emission indicators for energy consumption (GBT 51366-2019). Once it is found that carbon emissions exceed the approved indicators, new indicators will be automatically purchased in the carbon trading market.

The IoT hardware on all production equipment mentioned above does not need to be connected to the participating parties' systems. Participants only need to access the data via the device's key. Maybe this key is designed by the device developer as a client (such as an APP), then all parties only need to install a client to access all data generated by the device.

· Acceptance process

We assume that the strength of the concrete structure is written directly to the corresponding location of the BIM model by the testing equipment (IoT hardware) and written to the blockchain ledger.

3D laser scanning equipment can be used to generate point clouds to generate the building's exterior dimensions and number of steel bars and compare with the BIM design model. According to the quality inspection and evaluation standards, the percentage of honeycomb pitted surface can be accurately calculated. The acceptance accuracy will be much higher than manual calculation. Accuracy, written into the corresponding location of the BIM model and blockchain ledger.

All personnel and data involved in the acceptance are written into the blockchain ledger and stored permanently, which cannot be tampered with.

If a quality problem occurs, the ledger records on the blockchain are like a chronological ledger, starting from the current record and looking forward. Who accepted it? Who did it? Who moved it? Who bought it? It’s clear who provided it.

· Payment stage:

With the official issuance of digital RMB and its support for programmability, when digital RMB enters the field of project payment, it can be said that the destination of each project payment has been basically fixed and can be tracked on the blockchain. This is simply not going to happen. Misappropriation of project funds. Then when the project quality passes acceptance and meets the conditions set by the smart contract, the point-to-point payment operation of the smart contract will be automatically triggered. The company's financial costs can also be reduced by no longer going through banks.

Therefore, according to the provisions of the capital construction procedures, projects that do not have funds in place in the future will inevitably not be approved to start construction. For projects that have been approved to start construction, contractors, professional subcontractors, material suppliers and even labor personnel no longer need to worry about arrears in project payments. .

When BIM models are anchored to physical buildings and converted into digital assets, ownership of the digital assets can flow on the blockchain.

We assume that ownership of the physical engineering components temporarily remains with the contractor until the owner pays for the project. When a contractor encounters financial difficulties, the BIM digital assets on the blockchain (anchoring physical engineering components) just prove that if there is a certain future income (future payment of project fees by the owner), then the contractor can fully mortgage the loan. As part of the ownership of digital assets, smart contracts can lock in project payments from future owners for redemption by contractors. Return ownership of digital assets.

3.3. Operation and maintenance stage

A very good scenario in the operation and maintenance phase is the intelligent interaction between devices.

We assume that an unmanned patrol vehicle detects defects on the asphalt pavement on the highway through a computer vision recognition system and triggers a smart contract to start another asphalt pavement maintenance vehicle. This maintenance vehicle also uses smart contracts to automatically place orders for purchasing needs. Asphalt mixture repair materials automatically travel to the defect to complete the repair, with little or no human intervention in the process.

To sum up, blockchain technology + BIM can better realize smart construction. In turn, BIM models can be used as data dashboards for blockchain technology. With the continuous emergence of IoT hardware (especially in the operation and maintenance stage), as data continues to be filled, models are constantly refreshed, and dimensions become increasingly full, what you see is what you get. Blockchain + BIM will become a more intelligent intelligent construction decision-making system.

4. Summary

In this article, we list some applications in the three stages of planning, design, construction, and operation and maintenance. But the actual application scenarios are far more than these examples, and these examples can only be used as point-to-point discussions.

All technologies mentioned in the article are existing or already implemented functions (such as blockchain government systems, supply chain tracking, quality traceability, etc.). What is missing is the integration of these technologies. Just as blockchain technology is not a new technology in the first place, but the integration of existing computer technologies such as distributed storage, asymmetric encryption, and consensus algorithms, can this great invention be realized.

Some people may say that BIM forward design has not yet become popular in my country's construction industry, and 4D and 5D digital construction management based on BIM have just begun to become popular. Is it too early to discuss smart construction with blockchain technology + BIM?

And what I want to say is,

The concept of BIM was proposed as early as 1975 by a doctoral student at the Georgia Institute of Technology in the United States. In 2002, the company formally proposed BIM concepts and technologies. It started with 3D visualization and developed to today's 8D concept.

Blockchain technology was also proposed by Satoshi Nakamoto as early as 2008. In addition to digital currency, it has also been widely used in other non-digital currency fields.

Just like artificial intelligence technology,

It was first proposed by computer expert John McCarthy in 1956, but has been limited by computer technology and hardware. It was not until the 2012 challenge that the visual recognition accuracy reached over 95%, surpassing the limits of the human eye and breaking through the limitations of computer hardware and technology. The application of artificial intelligence technology ushered in a big explosion. In recent years, life applications such as beauty cameras, voice recognition, and smart push notifications have exploded in our mobile phones.

Therefore, before any technology breaks out in large-scale applications, energy is accumulating. This is a necessary process. On the one hand, it may be due to technical and hardware limitations, and another important reason is that there are too few people who understand and participate. Once everyone understands and masters it, this explosive power will naturally come into full play.

Just like we keep blowing up a balloon, one day it will burst.

标签： #Block #Model #Contract #Build #Application