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Top 8 Design and Code Mistakes for Structural Engineers

February 19, 2022|9 min read

A good structural design for a building will help reduce costs and save time. However, if the design is incorrect, it could cause more problems than expected. In addition, poorly designed structures have a higher probability of failing safety codes. This means that the owner must spend additional money to fix any code violations and improve structural safety. 

Structural engineers are constantly under pressure to deliver projects on time and within budget. The pressure is even greater when the project involves an existing building or structure that needs to be retrofitted with new technology. They are always looking for ways to include safe and economical specifications, but can sometimes make mistakes.

Early detection of structural design errors will result in the least financial and time impact on a project. Errors in structure designing can have a wide range of consequences, from minor inconveniences during the construction process to significant problems of the structural performance, such as the collapse of buildings.

Faulty structural analysis and ignorance in structural design is often the root cause of many design mistakes. Here are some common design errors made by structural engineers:

Inadequate Structural Redundancy

Redundant elements are necessary parts of a structure that protect the applied loads that exceed the capacity of other structural components. They may increase strength, improve stability, or prevent damage from occurring.

Redundant elements are essential to ensure that a structure does not fail due to overloads. For example, a bridge deck is usually supported by multiple trusses to prevent it from collapsing because of excessive loading. If one of these supports fails, the entire structure is still safe thanks to the redundancies in the structural systems.

However, if all of the supports failed, the entire structure would collapse. Therefore, the number of supporting members needed depends upon the loading conditions. Single support members are sufficient for small loads, but multiple support members are required for large loads.

Designing without redundancy is a common mistake made by inexperienced structural designers. When creating a structure, it is essential to consider how much load each element can withstand before breaking down.

Lack of Consideration for Loadings

Loadings are forces acting on a structure that produce stresses in its members. These stresses can lead to structural failure, so it is crucial to consider them when designing a structure.

For example, a beam is subjected to bending stress at both ends. The amount of bending stress depends on how much weight is placed on the beam.

If the beam is too heavy, it will bend excessively. This results in increased stress levels and eventually leads to structural failure.

If the beam is too light, it will not bear enough weight and cannot sustain the applied force. It will buckle and break.

If a single error happens in the applied loads calculation, the entire structure might fail. Hence, it is imperative to calculate the correct loadings before the structural design process starts.

Defective Connection Details

Connections between various structural components of a building are critical to the overall performance of the structure. For example, beams must be attached to columns with adequate connections to transfer the loads properly. 

A weak connection can affect the integrity of the whole system. In addition, poor connections can cause additional costs. For example, cracks in concrete floors can weaken the floor's ability to withstand earthquake loads.

The quality of the connection details is an area where many structural engineers fall short. They tend to focus more on the geometry of the connection rather than its material properties.

A weak connection can cause structural elements to fail, even under normal operating conditions. Poorly designed connections can also weaken a structure over time.

Calculation Error

Structural engineers use mathematical equations to determine the size and shape of structures. These equations are called formulae. Formulae are used to calculate the maximum allowable deflections of a beam or the maximum tensile stress in a steel column.

Formulae are based on geometric properties such as length, width, thickness, area, etc., and material properties such as Young's modulus, yield strength, ultimate strength, etc.

Formula errors occur when an equation is incorrectly written. When this happens, the result may be inaccurate and can undermine any safe and economical specifications.

Inaccurate calculations can have serious consequences. For example, if a formula is incorrect, the resulting value may exceed the maximum allowable deflection of a beam. This could result in the beam failing prematurely. The calculated values may be lower than what is possible. The result may be that the structure fails to meet the required standards.

Although everything is now calculated with software, a structural engineer must know the proper values.

structure functional planning

Ignoring Basic Code Provisions

Code provisions are rules that govern how a building is to be constructed. They specify what materials can be used and how they should be installed.

Some code provisions apply to all buildings, while others only apply to certain buildings. For example, some codes require fire-resistant construction materials. Other codes limit the type of materials used in a particular area due to environmental concerns.

The International Building Code (IBC) applies to all commercial and industrial buildings. It covers fire protection, electrical systems, plumbing, heating, air conditioning, elevators and escalators, sprinkler systems, lighting, and other safety issues.

Many states have adopted the IBC as their state codes. If you want to work in another state, you must learn the local codes. You should also check whether the local codes are consistent with the national codes.

The codes are set by local authorities and are enforced by inspectors who check whether the construction complies with code requirements.

Many designers ignore some lesser-known code provisions, but they should be aware of proper code provisions. Failure to comply with these provisions can have severe consequences and result in fines and demolition of the building.

Misusing Computer Software

Designers who work with structural analysis software must understand what information the software provides and interpret it correctly. Data interpreted incorrectly can result in inaccurate structural design.

For example, if a designer uses a software program to analyze the load capacity of a beam, they must enter the correct dimensions of the beam into the program. They must also input the appropriate loading conditions.

If the designer does not provide the correct information, the results may be misleading or invalid. This can lead to costly and even dangerous mistakes. If a design is based on faulty assumptions, the project may fail. In addition, the structural designer might face legal action.

When using computer software for modeling, it is essential to visualize the results. The designer must see where the forces act and the stresses are.

It is easy to get lost in the details and miss something important. Using the wrong software can lead to costly mistakes.

Detail Constructibility Problems

A designer's ability to draw accurate plans is critical to the success of any project. When planning a building, the first step is to create a set of drawings that show how the building will look once completed.

Drawing accurately requires good drafting skills. A professional drafter can produce high-quality drawings quickly and easily.

However, even the best drafter cannot consistently achieve perfect accuracy throughout the entire design process. If a drawing shows a problem, the designer needs to correct it before moving forward.

Constructibility problems must be identified early in the design process. They can cause delays and increase expenses. 

Inaccurate drawings can lead to problems during construction. Incorrect placement can affect the overall appearance and structural integrity of a building.

If the plan does not meet the specifications, the project will not be built correctly. This can result in delays and cost overruns. 

structural designers

Unclearly Communicated Design Intent

Designers often use vague language when communicating ideas to others. This type of communication can lead to misunderstandings and wasted time. 

When communicating ideas to others, it is essential for the structural designer to state their intentions clearly. In addition, it is helpful for them to explain the reasoning behind their decisions so that everyone understands why certain building elements were added.

If the structural engineer doesn't communicate clearly, other people might misunderstand their intentions and end up doing things differently. This can cause problems later on and could affect the entire structural system.

Communication between team members is an integral part of any project. It helps teams coordinate their efforts efficiently and effectively. Good communication ensures that all parties involved understand each other's roles and responsibilities.

Communication skills are essential to being a sound structural engineer. It is necessary to learn how to communicate your ideas and concerns effectively to others.

Many engineers fail to understand the basic purpose of their projects. If they don't know why they're working on a particular project, they won't perform well on it.

In Conclusion

Design errors are a symptom of dysfunctional organizational and maturation processes. As an engineer, you should avoid making these common mistakes in structural design.

Errors in structural planning significantly contribute to cost overruns, schedule delays, and even project cancelations. To avoid them, you need to develop a quality culture within your organization and make proper arrangements to share detailed knowledge and intended function of each structural element.

You need to establish a system for identifying and correcting errors before they occur. This means developing a formalized error identification and correction process.

Furthermore, errors jeopardize safety, increase costs, and may even expose you to legal liability. To avoid these risks, you need to implement a systematic approach to identifying and correcting errors.

A systemic learning framework helps you identify and correct errors before they cause too much damage. 

Structural Engineer

Advanced Software for Structural Engineering

Using software today, a structural engineer can accomplish increasingly complex tasks faster. This technology enables engineers to quickly generate detailed models of existing or proposed buildings.

Engineers can then test the structure's performance by applying loads and measuring responses. This allows them to predict potential design flaws before construction begins.

However, engineers must pay close attention to available tools when designing with advanced software. They must use only those features that are appropriate for the task at hand.

With StruCalc, you can streamline structural design for engineers and make it accessible to architects. Our structural analysis software offers a quick, convenient program with a multipurpose set of tools to help you execute everyday tasks quickly.

Why not give it a try? Start a free 30-day trial on any of our monthly subscriptions. You can download the program and get started in just five minutes!