Bridge construction: 10 stages to manage the entire process

In civil engineering, bridges are considered vital arteries connecting communities and enabling the uninterrupted flow of people, goods, and services. Building and maintaining these structures, however, pose a series of challenges that become increasingly demanding and complex over the years.

Now more than ever, seeking innovative solutions is necessary to address these challenges and ensure the safety, sustainability, and efficiency of our connecting infrastructures. In this article, we’ll delve into how the process of designing and constructing these structures unfolds and understand why bridge management software, bridge inspection software, and structural health monitoring software are indispensable tools for efficiently and effectively addressing critical challenges in the industry. You can try these tools for free by simply activating an account.

Example of bridge monitoring with usBIM

How is a bridge built?

The construction of a bridge allows for the crossing of natural or artificial obstacles, such as rivers, lakes, roads, valleys, or other geographical discontinuities. A bridge can therefore be defined as an engineering work aimed at connecting two separate points to allow the safe passage of people, goods, and vehicles from one side to the other.

To build a bridge, a process is required that is divided into several phases, including:

• site analysis and planning: this phase involves a careful assessment of the site and thus the characteristics of the land, the depth of the water where necessary, environmental conditions, and finally local regulations. After an important initial analysis phase, it is possible to move on to the next planning step. In this step, the type of bridge most suitable for specific needs is evaluated by considering the characteristics of the site, the expected traffic, and the available budget;
• design: in the design phase, we have all the necessary data to draft an initial project in which the dimensions of the bridge, the materials to be used, the geometry of the structure, and the structural characteristics are defined. This phase also includes key steps such as obtaining the necessary permits and planning resources;
• physical construction of the structure: the physical construction of a bridge is a fairly complex process that starts with the construction of the foundations and then moves on to the realization of the substructure and superstructure;
• control and testing: in this phase, quality controls of the materials and structure are conducted, as well as tests to verify the proper functioning of the bridge and compliance with current regulations.

Collaboration among engineers, architects, builders, local authorities, and other professionals is of fundamental importance in this process, necessary to ensure that the structure is designed and built safely and in compliance with all applicable regulations and standards.

Another aspect to consider when building bridges is related to the future maintenance needs of the structure. Only in this way will it be possible to identify in advance the critical components that require constant attention and implement the necessary interventions to protect the initial value of the infrastructure to ensure proper functioning over time and guarantee a high degree of efficiency, safety, durability, and sustainability.

What are the structural components of a bridge?

The elements composing a bridge vary depending on its structural type. There are arch bridges, beam bridges, truss bridges, suspension bridges, cable-stayed bridges, cantilever bridges, and so on. Here’s a quick breakdown of the main components of a bridge’s basic structure:

• Foundations are the base structures transferring the bridge’s weight to the underlying ground. Foundations can consist of poles, plinths, or similar structures;
• Abutments refer to support structures placed at the ends of the bridge, fundamental for ensuring the stability and safety of the structure;
• Pillars or Piers are the vertical elements that, together with the abutments, support the loads coming from the superstructure. Typically, they’re constructed in series along the bridge’s length to provide intermediate supports;
• Main beams are the main components of the bridge spanning between the pillars and abutments, serving to support the overlying elements. Depending on the structure type, they can be called longitudinal beams, transverse beams, or arches (if the bridge is an arch). They can be made of steel, reinforced concrete, or a combination of different materials;
• The deck is the functional area that allows vehicles and pedestrians to cross highways, valleys, and bodies of water. It can be made of different materials like concrete, steel, or wood and is supported by the main beams.

Structural components of a bridge

The bridge construction process: the 10 main stages

The process of building a bridge is highly articulated, requiring careful planning, considerable resources, and involvement of specialized expertise. The project’s duration and complexity can vary significantly based on the bridge’s size and type. It’s possible to simplify the construction process of these structures by leveraging the capabilities of digital twin technology for bridges.

The primary stages involved in bridge construction can be outlined as follows:

1. Planning and design: This initial phase involves engineers and designers evaluating the need to build a bridge and developing an overall project vision. It encompasses technical and economic feasibility studies and foreseeing aspects related to community needs, traffic flow, environmental conditions, safety criteria, and more. The outcome is an initial plan identifying the location, maximum dimensions, and type of bridge to be built;
2. Detailed design: Following the initial planning phase, the detailed design stage translates the starting idea into the complete project of the structure. Designers determine the exact dimensions of different components, perform strength and stability calculations, elaborate structural details, and define the materials to be used. Additionally, they outline maintenance strategies to ensure maximum safety and functionality of the structure over time;
3. Acquiring permits: Before commencing construction, obtaining various approvals from relevant authorities is necessary. These permissions may concern legal, environmental, and safety aspects. It’s crucial to ensure adequate funding to cover construction costs, which can be quite high;
4. Site preparation: This phase involves preparing the site where the bridge will be built. It includes removing trees, bushes, and excess soil. Additionally, the surface is leveled to provide a solid and even base for construction;
5. Foundation and substructure construction: The foundation is the bridge’s lower part transferring the load to the ground. This phase involves building footings, piles, pillars, or other supporting structures based on the site’s geological conditions. The foundations need to be robust to ensure structural stability;
6. Superstructure assembly: The superstructure supports vehicular or pedestrian traffic. Depending on the bridge type, it can consist of beams, spans, arches, or other elements. The construction of the superstructure can occur on-site or using prefabricated components, depending on the project’s specifications;
7. Installation of finishing elements: The final construction phase involves adding finishing details, including laying the road or pedestrian pavement, installing safety barriers and lighting systems, and introducing road signage. It’s crucial for the bridge to be fully functional and safe before opening to traffic;
8. Inspection and testing: In the final phase, rigorous inspections are conducted to ensure compliance with safety regulations and design requirements. Before opening to the public, load tests are carried out to assess the bridge’s load-bearing capacity and verify its structural integrity;
9. Opening to traffic: After passing all inspections and tests, the bridge is ready to open to traffic. This marks the moment when the structure starts serving its primary purpose of connecting two separate areas;
10. Continuous maintenance: Once open, regular maintenance is essential to preserve the bridge’s durability and safety over time. This maintenance includes periodic checks (performed by specialized professionals, such as bridge inspectors) and other activities aimed at preventing structural and functional deterioration.

Technologies Transforming Bridge Construction

Digital technologies are revolutionizing bridge construction, making processes more efficient, safe, and sustainable. But what are the main innovations transforming the building bridge sector? Let’s take a look together:

• BIM (Building Information Modeling) and parametric design: BIM has now become a standard in infrastructure design, offering an integrated approach that improves collaboration among all parties involved in the construction process. On the other hand, parametric design, which involves creating three-dimensional digital models where the geometric and structural characteristics of the bridge are controlled by variable parameters, allows for the rapid generation of design variants to adapt to changes and optimize structural performance. Integration with BIM enables efficient data management and effective collaboration;
• Artificial Intelligence (AI) and machine learning: AI is playing a crucial role in civil engineering, improving the design, safety, and sustainability of infrastructures. Through predictive models and machine learning algorithms, it is possible to optimize construction and maintenance processes, predicting potential structural problems and improving resource management;
• additive manufacturing (3D printing) with WAAM technology: WAAM (Wire Arc Additive Manufacturing) technology allows for the creation of large metal components through the layer-by-layer extrusion of material. An emblematic example is the 12-meter pedestrian bridge in Amsterdam, 3D printed using this technology, which has demonstrated the possibility of creating complex structures with reduced time and costs;
• integration of BIM 4D and GIS: the combination of BIM 4D (which adds the time dimension to modeling) and GIS (Geographic Information Systems) allows for more effective management of infrastructure construction sites. This integration facilitates activity planning, monitoring of work progress, and environmental impact analysis, improving safety and operational efficiency;
• automation and robotics in construction processes: automation is becoming increasingly present on construction sites, with the use of robots for activities such as welding, assembly, and monitoring of structures. These technologies increase precision, reduce construction times, and improve worker safety. The use of drones for bridge inspection, for example, allows for the rapid detection of any damage or anomalies without disrupting traffic, while IoT devices can be used to monitor various parameters of bridges, such as vibrations, deformations, temperature, and traffic, enabling real-time monitoring and more efficient maintenance.

What tools are necessary in bridge construction and maintenance

Managing bridge construction and maintenance is a challenging activity, primarily focused on maintaining the physical and functional characteristics of the infrastructure over time.

Bridges undergo natural aging and wear due to exposure to weather conditions, excessive loads, traffic, and extreme events. All these factors negatively impact the structure’s strength and stability and can cause issues like cracking, corrosion, deterioration, and reduced load-bearing capacity.

To preserve the safety of individuals using the bridge, it’s crucial to monitor the structural behavior of the structure and collect real-time data to identify anomalies and significant changes promptly. Additionally, conducting periodic inspections to promptly detect any damage or signs of wear and implementing necessary precautions is essential.

Organizing the means, resources, and activities necessary to ensure adequate bridge maintenance also represents a challenge. Maintaining these structures requires complex logistical planning, along with immediate access to specialized equipment and qualified personnel to carry out the work.

It’s evident that the process of building, managing, and maintaining a bridge can be extremely complex. However, today, innovative solutions are available to reduce the complexity that has always characterized this sector. In particular, indispensable tools include:

• Bridge management software, enabling the creation and management of effective maintenance plans, optimizing activity scheduling, and storing all bridge-related information in a centralized cloud accessible from anywhere and any device;
• Bridge inspection software, systems for planning regular inspections, analyzing data for the entire structure directly on the BIM model, and rapidly identifying problems or defects before they become severe;
• Structural health monitoring software, tools for collecting data on the structural integrity of different elements using IoT sensors and smart devices. These tools allow constant monitoring of the bridge’s conditions for prompt intervention with preventive maintenance activities.

You can try these tools for free through the activation of an account on usBIM.

FAQ – Bridge Construction

What are the main types of bridges?

There are several types of bridges, each with specific characteristics:

• arch bridge: uses an arch to transfer weight to the base;
• beam bridge: made of horizontal beams supported by pillars;
• suspension bridge: the roadway is suspended by cables anchored to towers;
• cable-stayed bridge: similar to a suspension bridge, but with fan-shaped cables connected directly to the towers.

The choice of bridge type depends on factors such as the distance to be covered, ground conditions, and traffic requirements.

What materials and techniques are used in bridge construction?

Various materials are used in bridge construction, chosen based on the type of bridge, stresses, and the environment. The main ones are:

• reinforced or pre-stressed concrete, widely used for its compressive strength and durability;
• steel, chosen for its tensile strength and lightness, often used in suspension or arch bridges;
• wood, used in pedestrian or historic bridges, valued for its low environmental impact;
• composite materials (such as carbon fiber), used in specific cases to reduce weight and increase strength.

The most common construction techniques include:

• cast-in-place, where concrete is poured directly on site;
• prefabrication, with elements made in a factory and assembled on site;
• incremental launching or launching, used to erect structures without interfering with the traffic below.

What are the phases of bridge construction?

The construction of a bridge follows several fundamental phases:

• planning and design: site analysis, choice of bridge type, evaluation of materials and construction techniques;
• foundation construction: building support structures, such as piles or pillars, based on ground characteristics;
• assembly of the superstructure: installation of beams, arches, or cables, depending on the type of bridge;
• deck construction: laying the roadway or railway surface;
• finishing and testing: installation of safety barriers, lighting, and verification of the bridge’s stability and safety.

These phases may vary based on the type of bridge and the specific site conditions.

What are the structural elements that make up a bridge?

The constituent elements of a bridge can be categorized into: the superstructure and the substructure; the former consists of the roadway, deck, and beams, while the latter includes abutments (or supports) and foundations that support the piers (or columns).

Who designs and builds a bridge?

The design and construction of a bridge involve various professional figures:

• civil engineers: responsible for structural design and technical supervision;
• geologists and geotechnical engineers: analyze ground characteristics to determine the most suitable foundations;
• architects: contribute to the aesthetics and integration of the bridge into the surrounding environment;
• construction company: carries out the practical construction work.

How long does it take to build a bridge?

The duration of bridge construction depends on various factors, including:

• size and complexity of the bridge: larger or more complex designs require more time;
• environmental conditions: factors such as climate and site geology can affect construction timelines;
• availability of resources: the presence of materials, labor, and adequate equipment can speed up or slow down work.

In general, the construction of a bridge can take from a few months to several years.

What are the challenges in bridge construction?

Bridge construction can present various challenges, including: complex geological conditions; adverse weather conditions; environmental constraints; logistical limitations.

How is the safety of a bridge ensured?

The safety of a bridge is ensured through:

• accurate design: compliance with regulations and use of appropriate materials;
• controls during construction: periodic checks to ensure the quality of work;
• regular maintenance: inspections and interventions to prevent or correct any deterioration.