The Construction Secret Nobody's Talking About

Key Concepts

• Temporary Works: Structural engineering focused on designing structures for construction, demolition, and maintenance – not intended for permanent use.
• Construction Engineering: A specialized field encompassing temporary works, access solutions, and construction methodologies.
• Collaboration: Crucial interaction between temporary works engineers, contractors, superintendents, and field crews.
• 3D Modeling (SketchUp): Increasingly used for visualization, communication, and problem-solving in temporary works design.
• Code Gaps: Temporary works often falls outside the explicit guidance of standard building codes, requiring engineering judgment and industry consensus.
• Access Solutions: A primary challenge in temporary works, involving innovative methods to reach and work on structures.
• Demolition Planning: Complex process considering structural integrity, environmental factors, and proximity to existing structures.

Introduction & Podcast Announcement

The Structural Engineering Channel podcast episode features a discussion with Ian Eversol, a technical manager at Foothills Bridge, about misconceptions surrounding temporary works and construction engineering. The episode highlights the creative and challenging nature of this field, emphasizing the importance of collaboration and innovative solutions. Host Matt Bardle also announced a temporary pause in podcast production after over 170 episodes.

Ian Eversol’s Background & Entry into Temporary Works

Ian Eversol has 15 years of engineering experience, initially exploring various disciplines like geotechnical, utilities, and power. He transitioned into temporary works while working for a large general contractor, drawn to the problem-solving and variety it offered. His experience spans bridges, demolition, heavy civil projects, and occasional building projects, primarily supporting contractors during project execution. He emphasizes the dynamic nature of the work, requiring adaptability and a broad skillset.

Defining Temporary Works & Common Projects

Temporary works engineering addresses the structures and systems needed to enable construction, demolition, or maintenance of permanent structures. A common example discussed is bridge demolition. When a bridge is deemed insufficient, Foothills Bridge is tasked with safely removing it, often requiring strengthening the existing structure to support heavy construction equipment or designing temporary supports and access solutions (e.g., working from the riverbed) to avoid placing loads on the compromised bridge. Access is consistently identified as the primary initial challenge.

Misconceptions About Temporary Works

A significant misconception is that temporary works is “invisible” – not recognized as a distinct engineering discipline. It’s rarely covered in traditional university structural engineering curricula. While some US programs are beginning to incorporate construction engineering, many engineers are unaware of its existence, assuming it’s the responsibility of others. Eversol clarifies that temporary works requires dedicated engineering expertise, involving design, analysis, and stamping of plans, distinct from permanent structure design. He describes the initial reaction of colleagues as surprise that "temporary" work still needed engineers.

Design Challenges & Collaboration

Temporary works presents unique design challenges due to the lack of specific code guidance and the constantly changing conditions on construction sites. Access remains a central issue. Effective collaboration is paramount, requiring constant communication with the contractor’s team – project managers, superintendents, foremen, and even crew members. Understanding the contractor’s capabilities, limitations, and preferred methods is crucial. The engineer must balance structural integrity with the practicality of the construction process. Eversol stresses that a temporary works engineer cannot operate in isolation.

Demolition Methods & Considerations

Demolition methods range from traditional wrecking balls and explosives to more controlled techniques. The choice depends on factors like proximity to new structures (e.g., a new bridge built inches from the one being demolished), environmental sensitivity (e.g., waterways), and debris management regulations. Explosives may be used if debris can be dropped into a waterway and dredged out, but restrictions apply in environmentally sensitive areas. The demolition plan must navigate these constraints while ensuring the safety of the new structure.

Codes, Standards & the Standard of Care

Temporary works often operates in a grey area regarding building codes (ASC7, ASHTTO, IBC, ACI 318). While codes like ASE37 provide some guidance for structures under construction or demolition, they are often insufficient. Engineers rely on first principles and adapt permanent design codes, but must also uphold a professional standard of care. Insurance companies and clients demand rigorous analysis and safe designs, even in the absence of explicit code requirements.

Industry Efforts to Address Code Gaps

The ASCE Construction Institute’s Temporary Works Committee is actively working to address code gaps by developing best practices for common challenges, such as rebar cage installation, bridge demolition, and wind load considerations on temporary structures. These efforts aim to establish industry consensus and provide guidance where codes are lacking. The goal is to provide clear, reliable solutions for engineers facing these unique situations.

The Importance of Field Observation & Communication

Eversol emphasizes the importance of direct field observation and communication with construction crews. Understanding the practical challenges faced by those executing the work is crucial for refining designs and improving efficiency. He recounts an experience at the Bay Bridge where understanding the limitations of ironworkers influenced the design of access solutions. Communication is enhanced through 3D models and animations, which effectively convey complex geometries and construction sequences. Detailed written plans are often less effective than visual representations. Plans are often referred to as "bridge removal plans" or "erection plans."

Emerging Trends & Technologies

3D modeling, particularly using Trimble SketchUp, is becoming increasingly prevalent in temporary works. SketchUp’s ease of use allows for rapid prototyping and collaboration with contractors who may not have dedicated BIM teams. The key is finding the appropriate level of detail – enough to facilitate communication and problem-solving, but not so much that it becomes overly complex or time-consuming. The focus is on effective communication and practical solutions.

Final Advice: Embracing Creativity & Practicality

Eversol advises engineers to embrace creativity and unconventional solutions in temporary works. The high cost of downtime for construction crews creates a willingness to consider a wider range of options. While rigorous analysis is essential, the financial incentives often justify exploring innovative approaches. He encourages engineers to be open to “weird solutions” as long as they meet structural requirements and can be confidently stamped.

Conclusion

The episode underscores the critical role of temporary works engineering in successful construction and demolition projects. It highlights the need for specialized expertise, collaborative communication, and a willingness to embrace innovative solutions. The field is evolving, with increasing reliance on 3D modeling and ongoing efforts to address code gaps and establish industry best practices.