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Earthquake resistant buildings

Earthquake resistant buildings: Technologies and techniques for safety

Discover the importance of earthquake-resistant buildings with technologies and techniques to ensure seismic resistance and protect structures from earthquakes

In a country constantly facing seismic risk, the importance of having buildings capable of withstanding such events is crucial and indisputable.

This article delves into seismic design, which extends beyond mere seismic event resistance. It encompasses adapting constructions to evolving seismic safety regulations over time. This endeavor aims to safeguard human life and preserve property and cultural identity by minimizing structural damage caused by earthquakes.

Additionally, we’ll explore how this is made possible with technological aid from structural calculation software, without which ensuring building safety would be immensely challenging, if not impossible.

Structural calculation with graphic analysis and color mapping

Structural calculation with graphic analysis and color mapping

Understanding and Addressing Seismic Threats

The concept of seismic risk is fundamental in design. Specifically, seismic risk refers to assessing threats, consequences, and the probability of an earthquake in a given geographical area. This evaluation often adopts a probabilistic approach, analyzing historical and geological data to comprehend a region’s seismicity and manage potential outcomes of future earthquakes.

Probabilistic Approach and Design Parameters

The probabilistic approach is a vital tool in determining design parameters and ensuring construction safety. It relies on statistical data, given the significant uncertainty regarding when seismic events occur and their intensity. This method seeks to define the necessary resistance and protection levels to cope with various potential earthquakes an area might face over time.

Understanding seismic risk allows the assessment of potential effects stemming from such events. This includes considering potential structural damages, vulnerability of individuals and assets, as well as methods to minimize negative impacts.

Innovation and Adaptation

Earthquake-resistant buildings continually evolve through technological innovations and research. They adapt to new seismic behavior insights, guidelines, and regulations aimed at ensuring construction safety. The primary goal remains minimizing risks to human life and property by designing buildings capable of withstanding earthquakes and preserving people’s safety.

Designs accounting for seismic risk aren’t purely theoretical but translate into practical applications. Engineers and architects, supported by geological information and safety regulations, design buildings that effectively and efficiently tackle potential seismic threats through specific materials, foundations, and construction methodologies.

Resistance and Control of Seismic Shocks

Design techniques for earthquake-resistant buildings revolve around crucial concepts of shock resistance. The foundation of this approach involves considering seismic design actions, i.e., the forces of seismic events that a construction should withstand. A structure designed to elastically react to seismic events can incur controlled and limited damages, ensuring occupant safety and structural integrity.

The concept of ductile response plays an essential role, allowing controlled deformation of the construction, maintaining overall stability without abrupt failure. This perspective is vital in ensuring occupant safety and building robustness during earthquakes.

This necessitates the use of materials and structures capable of withstanding these forces and minimizing structural damages resulting from seismic shocks.

Structural control of a building with Edilus

Structural control of a building with Edilus

Passive Control Systems and Energy Dissipation

Reducing structural damage is a core objective in seismic design. Passive control systems focus on dissipating seismic energy, aiming to delay or minimize structural damage, providing a ductile response during earthquakes. These systems aim to limit the extent of damages and preserve structural integrity, ensuring building and occupant safety.

Moreover, considering other systems for structural control by collecting information ensures effective and precise monitoring. These structural health monitoring tools allow timely decisions based on detailed data.

Data acquisition occurs through sensors measuring variables like wind pressure, rainfall, temperature, etc. The data is:

  • acquired with a sampling frequency of 200 Hz;
  • subjected to preprocessing (eliminating noise effects, detecting and removing spikes, etc.);
  • transformed into variables related to the monitoring objectives;
  • analyzed to determine the structure’s status and identify potential issues;
  • used to develop preventive maintenance solutions.

Role of Passive Control Systems

Passive energy dissipation control systems employ various strategies. For instance, using viscous dampers, seismic isolators, or energy-absorbing devices can limit seismic forces. These systems allow the structure to dissipate excess seismic energy and provide controlled elasticity, reducing the risk of irreversible damages. The capacity to absorb seismic energy helps protect the building and ensures a flexible response to seismic forces.

Benefits and Applications

Passive control systems, such as energy-absorbing devices, offer significant advantages in earthquake-resistant buildings. These solutions not only reduce damages to constructions but also ensure greater safety for occupants, enabling structures to maintain integrity and functionality even after an earthquake. Implementing such systems requires precise design and installation, but the benefits in terms of seismic resistance and safety are crucial for construction durability.

Seismic design techniques revolve around fundamental concepts of resistance to seismic forces, determining a construction’s effectiveness in facing seismic events. Using materials and structures capable of withstanding these forces is essential to reduce structural damages caused by seismic shocks.

Structural Reinforcement for Existing Buildings

Many current structures were built during periods when technical standards didn’t adequately consider seismic forces. Although compliant with regulations at the time, these structures suffered significant damages during subsequent seismic events. Reinforcing existing structures is not only strictly related to seismic events but also caused by various issues:

  • material degradation: reinforcement corrosion, concrete deterioration, and masonry degradation;
  • structural changes: modifications in layout or loads;
  • increased loads: increased acting forces;
  • unexpected events: such as fires, hydrogeological disruptions, or ground settlements.

Reinforcing Reinforced Concrete Buildings

Seismic events highlighted typical collapse patterns in reinforced concrete structures. To mitigate or eliminate such damages, several reinforcement techniques can be adopted:

  • increasing strength and/or stiffness by adding an external frame, bracing systems, or reinforced concrete infills;
  • strengthening strength and/or stiffness by column jacketing with reinforced concrete or metallic jacketing;
  • enhancing deformability and ductility through FRP wrapping or cladding with high-performance fiber-reinforced concretes.

The latter intervention is more advantageous than others as it allows local action, achieving positive results in the overall structure. There’s an increased deformability capacity, granting individual elements greater ductility or correcting strength hierarchies.

FRP and HPC systems achieve these goals with considerable advantages over traditional techniques in terms of costs, realization times, ease of installation, reduced impact on original global masses and stiffness.

Reinforcement of a deteriorated column

Reinforcement of a deteriorated column

Reinforcing Masonry and Timber Buildings

Masonry and timber structures, often present in historical construction heritage, are particularly vulnerable to seismic stress. Composite materials like FRP and FRCM systems have shown effectiveness in mitigating seismic risks while maintaining a structural compatibility and economic sustainability approach.

FRP Systems and the Advantages of an Innovative Material

Fiber Reinforced Polymers (FRP) represent an innovative technology widely used in construction for structural reinforcement. These composite materials, consisting of a polymer matrix reinforced with fibers, originated from the aerospace field and successfully extended into the construction sector. Their flexibility and lightness allow for a wide range of applications, especially in reinforcing existing structural elements.

Advantages of FRP Systems

Unlike traditional techniques, FRP offers numerous benefits for earthquake-resistant buildings, such as:

  • increased structural strengths and ductility – among the main advantages of FRP systems is a significant increase in structural strengths without imposing visible structural modifications. FRP materials improve load-bearing capacities and mechanical properties of reinforced elements, ensuring excellent adaptability. Additionally, they confer greater ductility to the structure, allowing better management of deformations and improved absorption of seismic forces;
  • fast execution and reduced impact – another crucial advantage is the speed in implementing reinforcement applications with FRP systems. These interventions require shorter times compared to traditional techniques and have minimal influence on the building’s aesthetic appearance. Installation is faster and doesn’t require long periods of structure downtime, ensuring a quick return to regular building use;
  • economical sustainability and chemical resistance – FRP materials boast considerable economic sustainability. Implementing these systems requires fewer specialized tools, reducing costs and intervention times. Additionally, they offer chemical resistance, reducing corrosion effects and increasing structural durability;
  • innovation and efficiency – FRP systems have become a preferred choice in the structural reinforcement sector. Their multiple qualities, including strength, flexibility, rapid execution, and economic sustainability, make them an effective and reliable solution.

Video of Applying Reinforcements to Masonry Structures

In the following video, we’ll show you an example of how you can use a structural calculation software to ensure the safety of earthquake-resistant buildings.