Top 7 Structural Engineering Mistakes to Avoid
- Joe Lazzaretti
- Jul 21
- 17 min read
Updated: Sep 2
Structural engineering mistakes can lead to costly repairs, safety risks, and even catastrophic failures - especially in areas like the San Francisco Bay Area, where seismic activity and challenging soil conditions are constant threats. Here’s a quick rundown of the most common errors to watch out for:
- Poor Site and Soil Analysis: Inadequate geotechnical investigations can lead to foundation failures, uneven settlement, or collapse.
- Wrong Shoring System Design: Incorrect load calculations or unsuitable materials jeopardize temporary supports.
- Skipping Seismic Retrofitting: Ignoring retrofitting requirements puts older buildings at high risk during earthquakes.
- Neglecting Foundation Engineering: Overlooking foundation challenges can compromise stability, especially in seismic zones.
- Poor Documentation and Communication: Missing records and unclear communication lead to design flaws and safety risks.
- Not Inspecting Temporary Supports: Skipping inspections increases the likelihood of failure during construction.
- Wrong Construction Sequencing: Mismanaged phasing can destabilize structures and delay projects.
Each of these mistakes has serious consequences, from increased costs to endangering lives. The details below explain why these errors occur and how to avoid them.
Top 10 Structural Engineering Mistakes to Avoid.
1. Poor Site and Soil Analysis
Thorough site and soil analysis is the backbone of any successful structural engineering project. Skipping detailed geotechnical investigations or misinterpreting soil data can lead to serious issues, from flawed foundation designs to inaccurate load calculations.
Impact on Structural Integrity
When soil analysis is inadequate, the structural performance of a building is at risk. Poor investigations - such as conducting too few borings or skipping essential tests like the Standard Penetration Test (SPT) or Cone Penetration Test (CPT) - can result in incorrect load calculations and faulty foundation designs. These errors often lead to structural issues like cracking, uneven settlement, or even collapse. This risk is especially high in areas prone to seismic activity, where soil behavior under stress can further compromise a building’s stability[5].
Addressing Seismic and Soil Challenges in the Bay Area
The Bay Area presents unique challenges with its varied soil types, ranging from fill materials to clays susceptible to liquefaction. These conditions demand rigorous analysis to comply with local seismic codes, such as the California Building Code and city-specific amendments[4]. For new constructions and major retrofits, comprehensive site investigations are mandatory to address these risks. Engineers must also assess the potential for soil liquefaction - a critical factor that, if overlooked, can make structures vulnerable to ground failure and lateral spreading during earthquakes[5].
How Often These Errors Occur
Errors in site and soil analysis are more common than you might think, particularly on projects constrained by tight budgets or timelines. To cut costs or save time, some teams abbreviate geotechnical investigations or rely on soil data from nearby sites, which can lead to inaccurate assumptions. A high-profile example is the 2015 San Francisco–Oakland Bay Bridge project, where insufficient site analysis resulted in structural faults and cost overruns exceeding $45 million[4]. These kinds of mistakes often come to light during construction or after seismic events, when the true nature of the soil is revealed under stress. The fallout typically includes project delays and skyrocketing repair costs.
Cost and Safety Risks
The consequences of flawed soil analysis extend far beyond the construction phase. Poorly analyzed soil conditions can lead to foundations that fail to support the structure, making buildings prone to settlement, tilting, or collapse - especially during earthquakes. These risks not only endanger occupants but also drive up long-term costs. Repairs, retrofits, and even demolitions can become necessary, and buildings often require ongoing monitoring and periodic fixes over their lifetimes. In densely populated areas like the Bay Area, these failures can ripple out to affect entire neighborhoods, making comprehensive soil analysis a critical step for public safety and cost management[5].
2. Wrong Shoring System Design
Mistakes in shoring system design can compromise the stability of temporary supports. These errors often arise from inaccurate load calculations, using inappropriate materials, or overlooking the specific conditions of the site. This issue becomes even more critical in areas with challenging seismic activity or complex soil conditions.
Impact on Structural Integrity
Getting the load calculations right and selecting the proper materials are non-negotiable for ensuring the stability of shoring systems. When either of these is mishandled, the likelihood of temporary support failure increases significantly. Careful planning and execution in these areas are essential to maintain the structural integrity of the system.
Challenges in the Bay Area’s Seismic and Soil Conditions
The Bay Area presents unique challenges due to its seismic activity and diverse soil types, including soft soils and expansive clays. Shoring designs in this region must account for seismic loads and adapt to these ground conditions. Addressing both static and dynamic forces ensures that temporary supports can withstand the demands placed on them.
Frequent Issues in Structural Engineering Projects
Despite these technical demands, design errors remain common in structural projects. Tight deadlines and poor communication during the design phase often result in generic shoring solutions that fail to address site-specific challenges. To avoid these pitfalls, it’s crucial to prioritize detailed evaluations and clear communication throughout the planning process. This approach reduces the risk of overlooking critical local factors.
3. Skipping Seismic Retrofitting Requirements
Skipping seismic retrofitting is a risky decision that can have dire consequences. It involves neglecting to upgrade older buildings to meet modern earthquake safety standards. Often driven by the desire to save money, this choice significantly compromises the safety of both the structure and its occupants.
Impact on Structural Integrity
When seismic retrofitting is ignored, a building's ability to endure earthquake forces is severely weakened. Structures built before the introduction of modern seismic codes lack the necessary reinforcements to handle the intense, dynamic forces of an earthquake. This dramatically increases the likelihood of structural collapse.
"Seismic retrofitting is not only about meeting legal requirements but also about safeguarding lives and property in earthquake-prone regions. It is an investment in the safety and stability of buildings and, ultimately, the well-being of the people who occupy them." - S3DA Design [7]
History has shown the devastating effects of neglecting retrofitting. For example, during the 1985 Mexico City earthquake, a 20-story building suffered extensive damage due to resonance effects, while taller and shorter buildings nearby fared better [9]. Such vulnerabilities are particularly concerning in the Bay Area, where seismic risks are amplified by local geological conditions.
Relevance to Seismic Activity and Soil Conditions in the Bay Area
The Bay Area's unique geology makes seismic retrofitting a necessity. Buildings on bedrock generally perform better during earthquakes, but those on soft or filled-in soil face far greater risks [9]. For instance, a magnitude‑6.7 earthquake can produce forces equivalent to 1 G of acceleration and a peak velocity of 40 inches per second [9]. Unreinforced structures simply cannot handle such intense forces.
Additionally, the region's varied soil types - like expansive clays and soft soils - can amplify seismic vibrations, worsening the impact on vulnerable buildings. Whether a structure weathers an earthquake or suffers catastrophic damage often depends on these ground conditions.
Commonality of Occurrence in Structural Engineering Projects
Despite the risks, skipping seismic retrofitting is alarmingly common. Many property owners and developers view retrofitting as a discretionary expense rather than a critical safety measure. However, data shows that areas with mandatory seismic strengthening programs achieve far higher retrofit rates compared to those relying on voluntary measures [11].
Potential Cost and Safety Implications
The costs of neglecting seismic retrofitting can be staggering, both financially and in terms of safety. Buildings that fail to meet seismic standards may be declared public nuisances, forcing owners to undertake expensive repairs, demolition, or face usage restrictions imposed by city authorities [11]. These enforcement actions can quickly escalate into long-term financial burdens.
"Seismic retrofitting is a critical component of disaster resilience, helping communities mitigate the risks posed by earthquakes and protect lives and property." - McNeil Engineering [6]
Interestingly, research shows that increasing the design-level peak ground acceleration from 0.08 g to 0.21 g raises retrofit costs by just 14% [10]. This modest investment yields substantial safety benefits, especially when compared to the potential devastation caused by an earthquake.
Failure to retrofit can result in catastrophic outcomes, including building collapses, loss of life, injuries, and widespread property damage [6]. Businesses are also at risk, facing prolonged recovery periods, disruptions, and financial losses due to damage to non-structural components during earthquakes [8].
To prevent these outcomes, it's crucial to hire a licensed structural engineer to thoroughly assess a building's seismic vulnerabilities [7]. Equally important is understanding and adhering to local building codes and retrofitting regulations [7] to ensure that safety standards are met and risks are minimized.
4. Neglecting Foundation Engineering Challenges
Skipping over the details of foundation engineering is a risky gamble. While accurate soil analysis and well-thought-out shoring design are essential, ignoring the challenges tied to foundation engineering can jeopardize an entire structure. When engineers fail to properly evaluate or address geotechnical conditions, the results can be disastrous - structural failures, steep repair costs, and even safety risks.
Impact on Structural Integrity
Foundation engineering issues directly threaten a building's stability. Problems like differential settlement, capacity failures, or overall instability can creep in if these challenges are overlooked. This is especially concerning in areas prone to seismic activity, like the Bay Area, where the ground itself can become a hazard.
The Bay Area's geology is a tough puzzle. Earthquakes here don’t just shake the ground - they often spark secondary dangers like landslides, rockfalls, soil settlement, lateral ground spreading, and liquefaction [1]. These events can cause foundations to shift, sink, or lose their ability to support the structure. Expansive clay soils, which swell when wet, can exert enough pressure to crack foundations [1]. Add coastal erosion into the mix, and the risks to foundation stability grow even greater [1].
Relevance to Seismic Activity and Soil Conditions in the Bay Area
In a region as seismically active as the Bay Area, foundation engineering challenges are amplified. A recent study forecasts a high likelihood of the Hayward fault rupturing in a magnitude 6.8–7.0 earthquake within the next 30 years, with estimated damages reaching $82 billion [2]. Combine this seismic risk with the region's varied soil conditions, and you’ve got a recipe for trouble. For example, bayside areas built on landfill over soft bay mud are prone to consolidation settlement, which can cause uneven sinking of foundations [1]. Tall buildings in particular require in-depth geotechnical investigations to meet local codes and address these unique risks [2].
Commonality of Occurrence in Structural Engineering Projects
Foundation challenges are often overlooked in structural engineering projects - sometimes because of tight deadlines, budget limitations, or a lack of understanding about local geology. Engineers may rely too heavily on standard building codes instead of conducting thorough, site-specific investigations. This is especially common in retrofit projects, where existing foundations need careful evaluation and possible upgrades. In the Bay Area, the combination of seismic activity, diverse soil conditions, and strict building codes demands specialized expertise to navigate these challenges effectively [3].
Potential Cost and Safety Implications
Ignoring foundation engineering problems can lead to serious consequences, both in terms of safety and cost. Fixing foundation failures often requires extensive and expensive remediation, depending on the project's size. Worse yet, foundation instability can result in partial or total structural collapse, endangering lives and exposing stakeholders to legal liabilities. Earthquakes, in particular, can turn small foundation issues into catastrophic failures. To avoid such outcomes, engineers need to perform detailed site investigations, identify soil characteristics, and integrate seismic design principles from the start [3]. Staying updated on building standards is crucial, and the Geotechnical Engineer of Record should take the lead early in the project by creating a comprehensive site-investigation plan and geotechnical report. This approach ensures that potential foundation challenges are spotted and addressed before they escalate.
5. Poor Documentation and Communication
When structural engineering projects go off track, poor documentation and communication often play a major role. These issues can undermine everything - from the initial design phase to the quality of the final construction. In the Bay Area, where seismic risks and complex soil conditions demand absolute precision, lapses in record-keeping and communication can turn otherwise manageable challenges into expensive and dangerous problems. As we’ve discussed with soil analysis and shoring design, keeping detailed records and ensuring clear communication are just as important as executing technical tasks like foundation analysis.
Impact on Structural Integrity
Failing to document soil conditions, design calculations, or construction specifications properly - and failing to communicate these details effectively - can lead to misinterpretations, missed safety measures, and flawed designs. This is especially critical in seismic retrofitting projects, where a thorough assessment of the building is key to determining the right retrofit approach. Without clear documentation of existing conditions and retrofit requirements, contractors may install reinforcements that fall short or miss essential structural connections altogether [12].
Relevance to Seismic Activity and Soil Conditions in the Bay Area
In a region like the Bay Area, where seismic hazards are a constant concern, precise documentation and communication are non-negotiable. Experts estimate a 63% chance that the Bay Area will experience a magnitude 6.7 earthquake within the next 30 years [13]. Given this risk, geotechnical testing to evaluate soil conditions and liquefaction potential is critical [12]. During seismic retrofitting, clear communication ensures the safety of tenants and maintains building accessibility [12]. Without proper documentation of soil conditions and seismic design parameters, engineers might make incorrect assumptions, leading to ineffective solutions that could jeopardize safety.
Common Occurrence in Structural Engineering Projects
Issues with documentation and communication are widespread in structural engineering. Tight deadlines often push teams to skip thorough record-keeping, and the complexity of multidisciplinary projects increases the likelihood of miscommunication. In large-scale retrofitting efforts, incomplete or outdated construction documents frequently force engineers to make assumptions about the building’s existing conditions, raising the risk of errors.
Take the San Francisco Mandatory Soft Story Retrofit Program as an example. By August 9, 2016, over 5,000 buildings were required to participate in the program. Of these, more than 1,700 had filed for or been issued a permit, and over 700 had completed their retrofits [13]. Managing documentation and communication across thousands of projects like these requires a systematic approach to avoid gaps in information.
Potential Cost and Safety Implications
The consequences of poor documentation and communication are severe. After a major earthquake, between 43% and 85% of soft-story buildings could be red-tagged, meaning they would be deemed unsafe. This translates to roughly 1,200 to 2,400 structures, with 300 to 850 of these potentially collapsing [13]. These staggering figures highlight how critical proper documentation and communication are to preventing catastrophic outcomes.
From a financial standpoint, missing or incomplete records can cause costly delays, redesigns, and rework during construction. Retrofit plans should also account for potential future changes to the building [12]. Without accurate documentation of current conditions and future considerations, projects may face expensive modifications down the line.
Legal risks are another major factor. Building codes establish minimum safety standards, but insufficient documentation can leave engineers and contractors vulnerable to liability if structural failures occur. As stated in Division 88 of the Los Angeles Building Code:
"The provisions of this division are minimum standards for structural seismic resistance established primarily to reduce the risk of loss of life or injury and will not necessarily prevent loss of life or injury or prevent earthquake damage to an existing building which complies with these standards." [14]
Thorough documentation not only ensures compliance with these safety standards but also reduces liability risks and helps protect all parties involved.
At Golden State Shoring, we understand that detailed documentation and open communication are the cornerstones of safety, compliance, and long-term project success. These practices are not just procedural - they are essential for delivering resilient and reliable structures.
6. Not Inspecting Temporary Supports
After addressing foundation and documentation challenges, it's crucial to highlight another common oversight in construction: neglecting temporary supports. These supports are essential for holding a project together while the permanent structure takes shape. Yet, they’re often overlooked until something goes wrong - a risky gamble, especially in the Bay Area. With its seismic activity and unpredictable soil conditions, this region demands constant attention to temporary supports. Regular inspections aren’t optional; they’re a must for ensuring both project stability and worker safety.
Impact on Structural Integrity
When temporary supports fail, the entire project can be at risk. No matter how high the material quality is, it cannot compensate for a lack of inspections.
"Temporary works must be designed and constructed with the same degree of competence and quality as required for permanent works." - CROSS Safety Report [16]
Examples from Europe and Asia serve as grim reminders of what happens when inspections are skipped. In those cases, missing structural elements and design flaws caused catastrophic collapses - disasters that could have been avoided with proper oversight.
Why This Matters in the Bay Area
The Bay Area’s unique geology makes temporary support inspections especially critical. Earthquakes can shift loads unexpectedly, while variable soil and groundwater conditions can weaken supports during excavation. In seismic retrofitting projects, these supports often face extra strain, holding up aging structures until new reinforcements are in place. In such scenarios, frequent and thorough inspections are non-negotiable for maintaining safety.
A Common Oversight in Construction
Skipping regular inspections of temporary supports happens more often than you’d think. Tight deadlines and budget pressures frequently push these inspections down the priority list. Unauthorized changes or deviations from the original design can introduce serious risks that may go unnoticed without routine checks [15]. Modern construction’s complexity - with multiple trades and ever-changing site conditions - further increases the likelihood of accidental damage, making consistent oversight even more critical.
The Cost of Neglect
The financial and safety consequences of neglecting temporary support inspections can be devastating. Over time, a lack of maintenance reduces the load-bearing capacity of these supports [17].
"Responsibility for and scope of inspections for temporary works must be clearly assigned and documented on-site. Inspections should be undertaken by competent staff." - CROSS Safety Report [16]
Failures in inspection can lead to costly delays, emergency repairs, and serious safety hazards. Often, these issues stem from inadequate training, inexperience, or poor oversight [17]. This makes it clear why inspections should always be conducted by qualified professionals who understand the unique challenges of Bay Area construction.
At Golden State Shoring, we recognize that inspecting temporary supports isn’t just about meeting regulations - it’s about ensuring project success and protecting lives. Our thorough inspection and maintenance protocols are designed to keep these supports performing reliably at every stage of construction. By prioritizing safety and precision, we help lay the groundwork for secure and successful projects across the Bay Area.
7. Wrong Construction Sequencing and Phasing
One of the most critical missteps in structural engineering is poorly executed construction sequencing and phasing. In areas like the Bay Area - where seismic activity and complex soil conditions present unique challenges - mismanaged sequencing can compromise a structure's stability and safety.
Impact on Structural Integrity
Construction sequencing plays a direct role in how loads are distributed throughout a structure during different stages of the building process. When sequencing is mishandled, it can lead to premature removal of supports or overloading of structural elements. This is especially concerning because shoring systems depend on precise timing to maintain stability and ensure worker safety[18]. Mistakes in sequencing can result in soil collapse, structural damage, or even violations of safety regulations.
The interplay between temporary and permanent supports is especially critical during phase transitions. Properly designed shoring systems are essential to maintaining a secure environment as construction progresses. Any disruption in sequencing can overload these supports or lead to improper deployment, which could cause catastrophic structural failures.
Challenges in the Bay Area's Seismic and Soil Conditions
These risks are amplified in the Bay Area due to its seismic activity and diverse soil conditions. Partially completed structures are particularly vulnerable in this region, where precise sequencing is essential to withstand environmental stresses. Deep excavations, for example, carry risks like cave-ins and falling debris, making it crucial to deploy shoring systems in the correct order[18]. Missteps can destabilize nearby structures or compromise the integrity of the excavation site, creating hazards for workers and the surrounding environment.
Why Sequencing Errors Are So Common
Errors in sequencing often arise from tight project timelines, poor coordination, and inadequate planning. When multiple contractors are working on-site simultaneously, conflicts in the construction sequence are almost inevitable - especially when structural work overlaps with utility installations. To avoid these pitfalls, contractors must select shoring equipment tailored to the specific site conditions and adhere to a carefully planned sequence[18]. Unfortunately, these errors are more common than they should be, leading to serious safety and financial consequences.
Financial and Safety Risks
The cost of sequencing mistakes can quickly spiral, with emergency repairs, project delays, and potential structural failures adding up to significant expenses. Beyond the financial burden, worker safety is directly tied to the proper use of equipment and adherence to site-specific requirements at every stage of construction. Using compliant and efficient shoring systems can help reduce downtime, minimize safety risks, and avoid regulatory penalties[18].
At Golden State Shoring, we recognize that a well-thought-out shoring plan is essential for maintaining project stability and avoiding costly setbacks. Our comprehensive approach to sequencing ensures that risks are minimized and projects stay on track. Just as proper soil analysis and shoring design are critical, meticulous construction sequencing is the foundation for protecting both the structure and the people who rely on it.
Conclusion
Structural issues in the Bay Area pose serious risks to both lives and investments, given the region's challenging seismic activity and soil conditions [20]. The seven critical errors we've discussed - from skipping thorough site analysis to mishandling construction sequencing - highlight the need for careful planning, precise execution, and unwavering attention to detail at every stage of a project.
In California, where most residents live within 30 miles of an active fault, these risks are magnified. Proper retrofitting and foundation work aren't just important - they're essential for safeguarding lives and financial investments [20]. Cutting corners in structural engineering can have catastrophic consequences, both in terms of human safety and economic impact.
Clear documentation and communication are vital to avoiding these pitfalls. From ensuring accurate load calculations to maintaining detailed soil condition records and coordinating construction phases, collaboration among engineers, contractors, and project managers is key. Poor documentation can lead to misunderstandings, mistakes, and potentially devastating failures that jeopardize safety and drive up costs.
Seismic retrofitting, in particular, requires expert evaluation and a focus on what truly matters. As one expert explains:
"The shallow footings will make no difference in keeping the house attached to the foundation and this is the purpose of retrofit work. It is not important if the footings are shallow. At the very worst the foundations may move slightly on top of the ground. The important thing is to keep the house on the foundation" [19].
This perspective underscores the importance of professional judgment in addressing structural challenges and dispelling common misconceptions.
Adhering to seismic codes is non-negotiable for ensuring safety and structural stability. The Bay Area's complex geological conditions demand tailored solutions for shoring, foundation design, and retrofitting. Generic approaches simply won't suffice when soil conditions can vary so dramatically - even within a single site.
At Golden State Shoring, we know that avoiding costly mistakes takes more than technical expertise. It requires a deep understanding of local conditions, meticulous planning, and an unwavering commitment to safety at every step. Our specialized services in foundation design, seismic retrofitting, and shoring are designed to meet the unique demands of Bay Area projects.
Neglecting these critical details can lead to delays, soaring costs, and compromised safety. Investing in professional expertise from the start is not just smart - it’s essential for ensuring the long-term stability and success of your project.
FAQs
What steps should I take to ensure a proper site and soil analysis for earthquake-resistant foundations in the Bay Area?
To ensure reliable site and soil analysis in earthquake-prone regions like the Bay Area, the process begins with a detailed geotechnical investigation. This involves methods such as soil sampling, drilling, and in-situ testing techniques like the Standard Penetration Test (SPT) or Cone Penetration Test (CPT). These tests provide crucial insights into the soil's strength, composition, and overall stability.
In addition to these, geophysical testing methods - like seismic refraction or cross-hole seismic testing - are essential for understanding how the ground responds to seismic activity. This information helps identify potential hazards, such as liquefaction or excessive ground shaking. With this thorough analysis, you can develop a foundation system designed to reduce the risk of structural failure during an earthquake, prioritizing both safety and durability.
What should you consider when designing shoring systems for areas with seismic activity and unstable soil?
Designing shoring systems in areas prone to seismic activity and tough soil conditions demands a thoughtful and precise strategy. The process begins with a thorough geotechnical investigation to evaluate soil stability, composition, and how it behaves under stress. This critical data helps determine the best shoring method - whether it's hydraulic systems, secant piles, or another option - customized to meet the site's unique requirements.
Integrating seismic design principles is key to ensuring the system can handle ground movement and vibrations effectively. Careful planning, detailed risk assessments, and strict adherence to safety standards are essential to minimize the risks of soil shifts or seismic forces causing failures. Partnering with seasoned engineers and following local building codes closely will further enhance safety and maintain the structure's integrity.
Why is it crucial to retrofit older buildings for earthquakes, and what are the risks of not doing so?
Seismic retrofitting plays a crucial role in ensuring the safety and stability of older buildings. By reinforcing their structure, retrofitting helps these buildings better withstand the powerful forces of an earthquake. This not only protects the people inside but also reduces the chances of a collapse and limits damage to the building. In earthquake-prone areas like the Bay Area, the need for retrofitting becomes even more urgent due to the higher frequency of seismic activity.
Neglecting retrofitting can lead to serious consequences, such as structural failures, costly repairs, and, most critically, risks to human lives. Many older buildings were not constructed with modern seismic standards in mind, leaving them particularly susceptible during an earthquake. Retrofitting is an investment in safety, property preservation, and compliance with local building regulations that aim to safeguard communities in these high-risk regions.
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