Structures & Models

Lateral load resisting system

Seismic Design on Soft Soils:

Soft soil can significantly impact seismic design considerations for buildings and infrastructure. When designing structures in areas with soft soil or liquefiable soil conditions, engineers must take special precautions to ensure their stability during an earthquake. Here are some key factors to consider:

1. Liquefaction: Soft soils, especially those with high water content, can undergo liquefaction during an earthquake. This process causes the soil to temporarily lose its strength and behave like a liquid, which can lead to settlement, tilting, or even collapse of structures. Engineers may use deep foundations, ground improvement techniques, or soil densification methods to mitigate liquefaction risks.

2. Site-Specific Analysis: Engineers conduct site-specific geotechnical investigations to assess the soil conditions at a particular location. This includes soil testing, determining the groundwater table, and evaluating the potential for liquefaction and ground shaking. The findings guide the seismic design of foundations and structural elements.

3. Foundation Design: Soft soil requires special foundation design considerations. Deep foundations, such as piles or caissons, may be used to transfer building loads to more stable soil or bedrock layers. Engineers may also incorporate base isolators or damping systems to reduce seismic forces transmitted to the structure.

4. Seismic Retrofitting: In regions with existing structures built on soft soil, seismic retrofitting becomes crucial. Retrofit measures can involve strengthening the building's foundation, adding shear walls or bracing systems, and improving overall structural integrity to enhance earthquake resistance.

5. Building Codes and Regulations: Local building codes and regulations often include provisions specific to seismic design in soft soil areas. These codes set minimum standards for construction practices and materials to ensure safety during earthquakes.

6. Dynamic Analysis: Engineers use dynamic analysis methods, such as response spectrum analysis and time-history analysis, to simulate the effects of ground motion on structures in soft soil. These analyses help refine the design to withstand expected seismic forces.

Overall, seismic design in soft soil regions demands careful consideration of site-specific factors, geotechnical engineering expertise, and compliance with relevant building codes to minimize earthquake risks and protect structures and occupants.

By:Jamal Qadamani

Soil classification as per IBC Code:

The International Building Code (IBC) is a widely adopted set of building regulations in the United States, and it provides guidelines for seismic design. In accordance with the IBC, determining soil class for seismic design involves the following steps:

1. **Geotechnical Investigation:** A geotechnical investigation is conducted at the site to collect soil samples at various depths. This investigation aims to assess soil properties and stratigraphy. The depth and locations of soil borings are determined in accordance with IBC requirements.

2. **Laboratory Testing:** Soil samples obtained from the site are subjected to laboratory testing, which includes but is not limited to:
- **Standard Pe*******on Test (SPT):** Measures soil resistance to pe*******on.
- **Cone Pe*******on Test (CPT):** Provides data on soil resistance and pore pressure.
- **Triaxial Tests:** Determines soil shear strength properties.
- **Grain Size Analysis:** Classifies soil based on particle size distribution.

3. **Soil Classification:** Based on the results of laboratory tests and field investigations, the soil is classified according to the IBC's Soil Profile Type. The IBC provides guidance on how to classify soil types, such as Site Class A, B, C, D, or E, with Site Class A representing the most stable soil conditions and Site Class E representing the most potentially unstable conditions.

4. **Site-Specific Parameters:** Once the soil profile type is determined, the IBC provides tables and equations to calculate site-specific seismic design parameters. These parameters include:
- **Seismic Design Category:** Determined based on factors like ground motion and the building's occupancy and importance.
- **Response Spectra:** Used to characterize the site's expected ground motion response during an earthquake.
- **Seismic Coefficients:** Used for lateral force calculations and structural design.

5. **Foundation Design:** The determined soil class and seismic parameters play a crucial role in the design of building foundations. Engineers use this information to select appropriate foundation types and design them to resist seismic forces effectively.

6. **Compliance with IBC Requirements:** Engineers and designers ensure that the seismic design of the structure complies with the IBC's seismic provisions, which specify design loads, detailing requirements, and construction practices for earthquake resistance.

In summary, in accordance with the International Building Code (IBC), the process of determining soil class for seismic design involves conducting geotechnical investigations, performing laboratory tests, classifying soil according to the IBC's Soil Profile Type, calculating site-specific seismic parameters, and using this information to design foundations and structures that can safely withstand seismic events. Compliance with IBC provisions is essential to ensure the safety and stability of buildings during earthquakes.

By: Jamal Qadamani

الجميع

الإنشائيون Structural Engineers

Return Period in Seismic Design:

The "return period" in seismic design refers to the average period of time between the occurrence of earthquakes of a certain magnitude or intensity in a specific region. It's a fundamental concept in assessing seismic risk and designing buildings and structures to withstand potential earthquakes.

In seismic design, engineers and seismologists use historical earthquake data and probabilistic seismic hazard analysis to estimate the likelihood of earthquakes of varying magnitudes occurring within a given area over time. The return period is typically expressed in years.

For example, if a region has a 100-year return period for a certain level of seismic ground motion, it means that there's an estimated 1% probability of an earthquake of that magnitude or greater occurring in any given year.

Seismic design codes and standards, such as those found in building codes like the International Building Code (IBC) in the United States, take into account the return period to determine the seismic forces that buildings and structures must be designed to withstand. Structures in regions with a higher seismic hazard, characterized by shorter return periods, will need to be designed to resist stronger seismic forces.

The goal of seismic design is to ensure that buildings and structures can withstand the expected seismic forces associated with their region's specific return period, reducing the risk of damage or collapse during an earthquake.

By: Jamal Qadamani

International Building code - Seismic Design

The International Building Code (IBC) provides comprehensive guidelines and standards for seismic design considerations in buildings. Here's a revised version of the seismic design considerations for buildings in accordance with the IBC:

1. **Seismic Zone Determination**: The IBC divides regions into seismic zones based on seismic hazard. Architects and engineers must determine the applicable seismic zone for the building's location to establish appropriate design parameters.

2. **Occupancy Classification**: Buildings are categorized based on occupancy, such as residential, commercial, or industrial. Each occupancy type has specific seismic design requirements outlined in the IBC.

3. **Foundation Engineering**: Proper foundation design is fundamental. Soil testing and analysis inform the selection of foundations, which may include shallow foundations, deep foundations, or specialized systems like base isolators or caissons.

4. **Lateral Force-Resisting Systems**: Buildings must resist lateral forces generated by earthquakes. Engineers employ various lateral force-resisting systems, such as shear walls, braced frames, or moment frames, as per IBC guidelines.

5. **Damping Systems**: To mitigate structural motion and reduce damage, damping systems like tuned mass dampers or viscous dampers may be integrated into building design, adhering to IBC specifications.

6. **Materials and Construction**: High-strength materials like reinforced concrete and steel are commonly used in seismic design, ensuring the building's ability to deform without catastrophic failure, in accordance with IBC standards.

7. **Anchorage of Non-Structural Elements**: IBC mandates secure anchorage for non-structural components, including HVAC systems, piping, and partitions, to prevent them from becoming hazards during an earthquake.

8. **Seismic Bracing**: Buildings may incorporate diagonal braces or other bracing methods specified in the IBC to enhance lateral stiffness and stability.

9. **Redundancy**: The IBC emphasizes the importance of redundancy in structural systems to improve resilience, ensuring that if one element fails, others can provide support.

10. **Egress Planning**: Safe and clear emergency egress paths are essential. IBC-compliant stairwells and exit routes must remain functional during and after an earthquake.

11. **Regular Inspection and Maintenance**: To identify and address structural issues, regular inspections and maintenance align with IBC requirements, ensuring the building's long-term safety.

12. **Building Height**: Tall buildings may require additional measures like tuned mass dampers or damping systems to reduce sway and enhance seismic performance, as stipulated by the IBC.

13. **Local Building Codes**: Compliance with the local building codes, which often incorporate IBC seismic design requirements, is mandatory.

14. **Seismic Retrofitting**: Existing buildings may need retrofitting to meet current IBC seismic standards and enhance their earthquake resistance.

Seismic design, in accordance with the IBC, strives to strike a balance between occupant safety and cost-effective construction. Architects and engineers collaborate to design buildings that can withstand seismic forces and minimize damage and collapse risks during earthquakes, adhering to the rigorous standards set forth by the IBC.

By Jamal Qadamani

Stability of Tower, be careful

The stability of a tower is a critical consideration in its design, construction, and maintenance. Towers, whether they are communication towers, observation towers, or high-rise buildings, must be engineered to withstand various forces and ensure the safety of occupants, as well as the longevity of the structure. Here are some key factors related to the stability of a tower:

1. **Foundation**: The stability of any tower begins with its foundation. A solid and well-engineered foundation is essential to distribute the weight of the tower evenly and prevent settling or tilting.

2. **Structural Design**: The tower's structural design must account for its intended purpose and the forces it will encounter. This includes wind loads, seismic activity, and the weight of the tower itself and any equipment or occupants.

3. **Materials and Construction**: The choice of materials and construction methods plays a crucial role in stability. High-strength materials and precise construction techniques are necessary to ensure the tower's integrity.

4. **Wind Resistance**: Towers are particularly vulnerable to wind forces due to their height. Engineers use aerodynamic principles to design towers that can withstand high winds without excessive sway or deformation.

5. **Seismic Considerations**: In earthquake-prone regions, towers must be designed to absorb and dissipate seismic energy safely. This involves flexible construction methods and seismic bracing systems.

6. **Maintenance**: Regular inspection and maintenance are essential for long-term stability. Any signs of structural wear, corrosion, or damage must be addressed promptly to prevent potential instability.

7. **Occupant Safety**: For towers housing people, safety measures such as emergency evacuation plans and fire protection systems are essential components of stability.

8. **Environmental Factors**: Environmental factors like temperature fluctuations and moisture can affect the stability of a tower over time. Proper coatings and insulation can mitigate these effects.

9. **Monitoring**: Some towers are equipped with monitoring systems that continuously assess their stability. These systems can detect any anomalies or movements and alert operators to take corrective action.

In conclusion, the stability of a tower is a complex and multifaceted aspect of its design and maintenance. It requires careful planning, engineering expertise, and ongoing vigilance to ensure the safety and functionality of these structures, which often serve critical roles in various industries and communities.

By Jamal Qadamani

Earthquake in Palestine :

Seismic activities in Palestine can vary depending on the specific region and geological conditions. Generally, Palestine is located in a seismically active area due to the tectonic plate boundaries in the eastern Mediterranean region. Some key seismic parameters to consider include:

1. Seismic Hazard: Palestine is susceptible to earthquakes, with varying levels of seismic hazard across different areas. The Palestinian territories are situated near the Dead Sea Transform Fault, which is a major tectonic boundary.

2. Magnitude: Earthquakes in Palestine can range in magnitude, with the potential for both small and large quakes. Historical records show instances of earthquakes with magnitudes ranging from 4.0 to 7.0 or higher.

3. Depth: The depth at which earthquakes occur can influence their impact. Earthquakes can originate at shallow depths near the surface or at deeper depths within the Earth's crust.

4. Frequency: The frequency of seismic events can vary, but the region experiences periodic seismic activity.

It's important for local authorities and communities to be aware of these seismic parameters and take appropriate measures to mitigate earthquake risks through building codes, emergency preparedness, and public awareness programs. Additionally, ongoing monitoring and research help in better understanding and predicting seismic activity in the region.

By Jamal Qadamani

Probability of exceedence in IBC response spectra:

In the International Building Code (IBC) 2012, as well as in subsequent editions, the response spectra are often presented with associated probabilities of exceedance rather than explicit return periods. The probability of exceedance indicates the likelihood of a particular level of ground motion being exceeded or equaled in a given time period.

Typically, response spectra in the IBC are provided with probabilities of exceedance such as 2%, 5%, and 10% in 50 years (or sometimes different time periods depending on the specific region or code edition). For example, a 5% probability of exceedance in 50 years means that there is a 5% chance that the ground motion represented by that spectrum will be exceeded or equaled at a specific location within a 50-year time frame.

These probabilities of exceedance are derived from seismic hazard assessments and are used to establish design ground motion values for different risk levels in building codes. Engineers select the appropriate response spectrum and associated probability of exceedance based on the seismic design category and location of a particular project to ensure that structures are designed to withstand the expected seismic forces.

By Jamal Qadamani

متطلبات السلامة العامة والصحة في المشاريع الإنشائية:

1. **تقدير المخاطر:** يجب على المقاولين والمهندسين تقدير المخاطر المحتملة في المشروع ووضع استراتيجيات للتعامل معها. يشمل ذلك تحليل الأمان وتحديد ما إذا كانت هناك حاجة لتطبيق إجراءات إضافية للحماية.

2. **توفير معدات السلامة:** يجب توفير معدات السلامة الضرورية للعمال في موقع البناء، مثل خوذ السلامة، ونظارات الحماية، وقفازات العمل، وحزام السلامة عند العمل في الأماكن المرتفعة.

3. **التدريب والوعي:** يجب توفير تدريب للعمال حول كيفية العمل بأمان والتعامل مع المواد الخطرة. يجب أن يكون لديهم الوعي بمخاطر البيئة وكيفية تجنبها.

4. **إزالة المواد الخطرة:** يجب التعامل بعناية مع المواد الخطرة والتخلص منها بشكل آمن ووفقًا لللوائح المحلية والوطنية.

5. **الحماية من السقوط:** في الأماكن المرتفعة، يجب استخدام أنظمة الحماية من السقوط مثل الحبال والسلالم والسياج.

6. **إجراءات الإسعافات الأولية:** يجب توفير معدات إسعافات أولية وتدريب العمال على استخدامها للتعامل مع الإصابات البسيطة أو الحالات الطارئة.

7. **مراقبة البيئة:** يجب على الجهات المعنية مراقبة جودة الهواء والمياه والتأكد من عدم وجود ملوثات خطيرة في الموقع.

8. **الامتثال للوائح:** يجب أن تلتزم المشاريع الإنشائية باللوائح والقوانين المحلية والوطنية المتعلقة بالسلامة والصحة المهنية.

هذه نقاط عامة، ويمكن أن تختلف المتطلبات بناءً على موقع المشروع ونوعه. يجب دائمًا استشارة الجهات المعنية والمتخصصين في مجال السلامة والصحة المهنية لضمان الامتثال الكامل والسلامة في المشاريع الإنشائية.

By Jamal Qadamani

General requirements for safety and health in construction projects:

1. **Risk Assessment:** Contractors and engineers should assess potential risks in the project and develop strategies to mitigate them. This includes safety analysis to determine whether additional protective measures are needed.

2. **Provision of Safety Equipment:** Necessary safety equipment such as hard hats, safety goggles, work gloves, and safety harnesses should be provided to workers on the construction site, especially when working at heights.

3. **Training and Awareness:** Workers should receive training on how to work safely and handle hazardous materials. They should be aware of environmental risks and how to avoid them.

4. **Handling Hazardous Materials:** Hazardous materials should be handled carefully and disposed of safely in compliance with local and national regulations.

5. **Fall Protection:** In elevated areas, fall protection systems like safety ropes, ladders, and fencing should be used to prevent falls.

6. **First Aid Procedures:** First aid equipment should be provided, and workers should be trained in its use to deal with minor injuries or emergencies.

7. **Environmental Monitoring:** Monitoring of air and water quality should be conducted to ensure there are no hazardous pollutants on the site.

8. **Compliance with Regulations:** Construction projects should adhere to local and national regulations and laws related to safety and occupational health.

By Jamal Qadamani

Do you what my is response spectra analysis??

Response spectra analysis is a technique used in structural engineering and earthquake engineering to assess the response of a structure to ground motion, typically generated by seismic events (earthquakes). It provides a graphical representation of how a structure will respond to various frequencies of ground motion.

How it works:

1. **Ground Motion Input:** First, the ground motion data from an earthquake or other dynamic event is collected. This data represents the accelerations that the ground experiences over time.

2. **Mathematical Transformation:** The ground motion data is mathematically transformed from the time domain to the frequency domain using techniques like the Fast Fourier Transform (FFT). This conversion allows engineers to analyze the data in terms of its frequency components.

3. **Response Calculation:** Next, the response of a structure to these different frequency components is calculated. This involves applying the ground motion data to a mathematical model of the structure to determine how it would vibrate at each frequency.

4. **Spectrum Generation:** The results are then plotted on a graph known as a "response spectrum." The x-axis of the graph represents various frequencies, while the y-axis represents the response of the structure (usually accelerations, velocities, or displacements). The graph provides a visual representation of how the structure responds to different frequencies of ground motion.

Response spectra analysis is valuable for structural engineers because it helps in:

- **Design:** Engineers can use response spectra to design buildings and other structures that can withstand specific levels of ground motion. By analyzing how the structure responds to different frequencies, they can tailor the design to reduce the risk of damage during an earthquake.

- **Assessment:** It allows engineers to assess the vulnerability of existing structures to seismic events. By comparing the response spectrum of a structure to design standards or code requirements, engineers can determine if the structure needs retrofitting or strengthening.

- **Risk Evaluation:** Response spectra analysis helps in evaluating the seismic risk of a region. Engineers can use historical earthquake data to generate response spectra for a given location, aiding in risk assessments and disaster preparedness.

In summary, response spectra analysis is a crucial tool in earthquake engineering and structural design, enabling engineers to understand and mitigate the seismic risks associated with structures.

Structural Stability of Towers

The stability of towers is a critical consideration in their design and construction, especially for tall structures such as skyscrapers, communication towers, or transmission towers. Several factors contribute to the stability of towers:

1. Structural Integrity: Towers must be designed with sufficient structural integrity to withstand various loads, including wind, seismic forces, and the weight of the tower itself. Structural engineers use complex calculations and simulations to ensure the tower can handle these loads without excessive deformation or failure.

2. Foundation Design: A stable foundation is essential to prevent a tower from leaning or collapsing. Engineers analyze soil conditions at the construction site and design foundations that can distribute the tower's load effectively. Deep foundations, such as piles or caissons, are often used for tall towers.

3. Wind and Aerodynamic Considerations: Tall towers are exposed to significant wind forces, which can cause swaying and vibrations. Engineers use wind tunnel testing and computational fluid dynamics (CFD) simulations to optimize the tower's shape and reduce wind-induced motion.

4. Dynamic Analysis: Engineers perform dynamic analyses to understand how the tower responds to external forces and to mitigate resonance or excessive vibrations that could compromise stability. Damping systems may be incorporated to reduce oscillations.

5. Material Selection: The choice of materials, such as steel or reinforced concrete, affects the tower's strength and durability. Engineers consider material properties and corrosion resistance to ensure long-term stability.

6. Maintenance and Monitoring: Regular maintenance and structural health monitoring systems are crucial to detect and address any issues that could compromise a tower's stability over time.

7. Geotechnical Factors: Geological and geotechnical conditions, including soil properties and seismic activity in the area, play a significant role in tower stability. Engineers must account for these factors in their designs.

8. Safety Regulations: Towers must adhere to local building codes and safety regulations to ensure they meet minimum standards for structural stability and safety.

Overall, the stability of towers is a complex and multi-faceted engineering challenge that requires careful analysis, design, and construction to ensure the safety and integrity of these tall structures.

By Jamal Qadamani

الإجراءات الواجب في أعمال الحفر

ضوابط الحفر لأعماق كبيرة في التربة الصعيفة تعتمد على مجموعة من العوامل والمعايير الهندسية التي يجب مراعاتها لضمان سلامة الهندسة المدنية والعاملين على المشروع. إليك بعض الضوابط الأساسية:

1. **التصميم الجيد**: يجب على المهندسين تقدير عمق الحفر بعناية باستخدام البيانات الجيوتقنية والجيوتقنيات المناسبة. يتعين على التصميم أن يكون متوافقًا مع الأحمال المتوقعة والظروف البيئية.

2. **اختبارات التربة**: يجب إجراء اختبارات تربة دقيقة لفهم خصائص التربة الصعيفة، بما في ذلك قوة التربة وتراكمها والاستجابة للحمل.

3. **تقييم الاستقرار الجانبي**: يجب تقييم الاستقرار الجانبي للحفرة المحفورة بعمق كبير. يشمل ذلك تقييم انهيار الجدران الجانبية واحتمالات الانزلاق.

4. **الإجراءات الوقائية**: يجب اتخاذ إجراءات وقائية مثل دعامات الحائط والتجميعات الهيكلية للحفائر العميقة للتحكم في انهيار الجدران الجانبية والمنع من الانهيار.

5. **مراعاة البيئة**: يجب مراعاة البيئة المحيطة والمخاطر البيئية أثناء الحفر. قد تكون هناك قوانين ولوائح تحتاج إلى الامتثال لها.

6. **الإشراف والمراقبة**: يجب أن يتم الإشراف والمراقبة المستمرة أثناء الحفر للتأكد من أن العمل يتم بما يتوافق مع الخطط والمعايير الهندسية.

7. **الجدولة الزمنية**: يجب وضع جدول زمني محدد للحفر والتقيد به لتجنب تأخيرات غير مرغوب فيها والحد من تأثير الحفر على المناطق المحيطة.

8. **التخلص من النفايات**: يجب التخلص من النفايات والمواد الزائدة بشكل صحيح ووفقًا للقوانين المحلية.

9. **التفتيش والصيانة**: بعد الانتهاء من الحفر، يجب أن يتم تفتيش الموقع بانتظام وإجراء الصيانة اللازمة للمنع من التراكمات غير المرغوب فيها أو الانهيارات.

تذكر أن هذه الضوابط تختلف باختلاف المواقع والتربة والتشريعات المحلية، ويجب دائمًا التعاون مع مهندسين محترفين والجهات الرسمية المختصة لضمان الامتثال الكامل وسلامة الحفر.

By Jamal Qadamani

Closely Spaced Modes in dynamic analysis:

Closely spaced modes of vibration" in structural models refer to vibration modes with natural frequencies that are relatively close to each other. These modes are an essential consideration in structural engineering and dynamics, and here's why they are significant:

1. **Frequency Separation**: In structural dynamics, structures have multiple vibration modes, each with its own natural frequency. When these natural frequencies are closely spaced, it means that the modes are relatively similar in frequency.

2. **Resonance**: Closely spaced modes are more likely to interact with external forces and each other. When an external force, like wind or seismic activity, matches the frequency of one of these modes, it can lead to resonance. Resonance amplifies the structural response, potentially causing excessive vibrations or damage.

3. **Mitigation**: Structural engineers must carefully analyze and consider closely spaced modes to avoid resonance. This may involve adjusting the design, altering support conditions, or adding damping systems to control vibrations and prevent structural damage.

4. **Dynamic Analysis**: Performing dynamic analysis on a structure is crucial to identify closely spaced modes and assess their impact. Engineers use specialized software to calculate natural frequencies and mode shapes, ensuring that the modes are sufficiently separated to avoid resonance.

5. **Design Challenges**: Closely spaced modes can present challenges in structural design, especially for tall buildings, bridges, or other complex structures. Engineers must ensure that the design does not inadvertently create conditions for resonance by keeping the modes well-separated.

6. **Dynamic Modification**: In some cases, structural modifications may be necessary to change the natural frequencies of a structure or adjust the mode shapes. This can help achieve safer and more efficient performance under dynamic loads.

In summary, closely spaced modes of vibration in structural models can pose a risk of resonance, which can lead to excessive structural vibrations and potential damage. Engineers must carefully analyze and manage these modes during the design and analysis of structures to ensure their safe and stable response to dynamic forces.

By Jamal Qadamani

For architects & structural Engineers

Avoiding Soft story in Structures for the following reasons:

Soft-story buildings, which have a weaker or less rigid ground floor compared to upper stories, are particularly vulnerable to performance issues during earthquakes. Here are some key aspects of how soft-story buildings perform during seismic events:

1. **Excessive Lateral Displacement**: Soft-story buildings tend to experience significant lateral displacement during earthquakes. The ground floor's weakness allows for greater lateral movement, which can result in structural damage or even collapse.

2. **Torsional Effects**: Soft-story structures are prone to torsional effects, where the building twists or rotates around its vertical axis. This can lead to uneven stress distribution and structural damage.

3. **Collapse Potential**: In severe earthquakes, soft-story buildings are at a higher risk of partial or total collapse, especially if they lack proper seismic retrofitting.

4. **Resonance**: The irregularity in stiffness between the ground floor and upper stories can lead to resonance with certain ground motion frequencies, causing further amplification of seismic forces.

5. **Soft-Story Failures**: Failures in soft-story buildings often occur at the ground level, where large openings like garages are common. These openings weaken the structure, making it susceptible to damage.

6. **Inadequate Lateral Load Resistance**: The inadequate lateral load resistance in soft-story buildings can result in extensive structural damage, including shear failures in columns and walls.

7. **Retrofitting Solutions**: Seismic retrofitting techniques are commonly employed to enhance the seismic performance of soft-story buildings. This may involve adding shear walls, bracing systems, or steel frames to strengthen the weak story.

8. **Building Codes**: Many regions with a history of seismic activity have updated building codes that address soft-story vulnerabilities. These codes often require retrofitting or design modifications to reduce the risk to occupants and nearby structures.

9. **Life Safety Concerns**: Soft-story buildings, if not retrofitted, pose significant life safety concerns for occupants and can also lead to a risk of injury or death to pedestrians or neighboring properties due to potential collapse.

In summary, soft-story buildings are susceptible to specific performance issues during earthquakes, primarily due to their weak ground floor and irregular stiffness distribution. Retrofitting and compliance with seismic codes are crucial to mitigate these vulnerabilities and enhance the earthquake resilience of such structures.

By Jamal Qadamani