Why Industrial Steel Structures Frequently Opt for Pinned Supports

Contrary to what one might think, industrial steel structures frequently use pinned supports due to several practical advantages over fixed supports. While fixed connections are commonly preferred in theory, in practice, most structures do not strictly adhere to rigidly fixed or purely pinned concepts. These theoretical concepts are useful during the preliminary design stages to quickly assess beam and column sizes, as well as a building's resistance to lateral forces.

Comparing Pinned and Fixed Connections

Pinned connections are generally simpler to construct and less costly than fixed connections. This is because they do not need to resist any transferred moment, thus allowing for smaller, more slender columns to be utilized in the design. Conversely, fixed connections can significantly reduce midspan bending moments and deflections of a beam. Under a central point load, the moment at the midspan of a fixed beam is only half that of a beam using pinned connections, and the deflection is four times smaller. This higher rigidity of fixed connections comes with a higher cost and complexity in terms of construction and design.

Key Reasons for Using Pinned Supports in Industrial Steel Structures

Several factors contribute to the frequent selection of pinned supports in industrial steel structures:

Flexibility and Movement

Pinned supports offer the crucial advantage of allowing for rotation and horizontal movement. This flexibility is particularly important in structures that might experience thermal expansion, wind loads, or seismic activity. By enabling the structure to adapt to these forces without developing excessive internal stresses, pinned supports help maintain the structural integrity and safety of the building.

Simplified Analysis

Pinned connections also simplify the structural analysis and design process. Engineers can treat these supports as two-dimensional systems, making it easier to calculate the forces and moments acting on the structure. This streamlining of the design process can significantly reduce the time and costs associated with the construction of industrial steel structures.

Load Distribution

Pinned supports help distribute loads more evenly throughout the structure. By allowing for a certain degree of movement, they can reduce the likelihood of localized stress concentrations that might occur with fixed supports. This even distribution of loads contributes to a more robust and stable structure.

Cost-Effectiveness

Pinned connections are typically easier and less expensive to fabricate and install compared to fixed connections. This cost-effectiveness is a significant factor in the widespread adoption of pinned supports in industrial steel structures, where project budgets and timelines are often critical considerations.

Redundancy and Safety

In the event of structural failure, pinned supports can help prevent total collapse by allowing other parts of the structure to redistribute loads. This redundancy is a critical aspect of ensuring the safety and integrity of industrial steel structures, especially in high-risk environments.

Ease of Maintenance and Modifications

Pinned supports also facilitate easier maintenance and potential modifications to the structure without the need for extensive reconstruction. This flexibility can be invaluable in the long-term management and evolution of industrial facilities.

Conclusion

In summary, pinned supports provide a balanced solution, offering a combination of flexibility, structural integrity, and cost-effectiveness. This makes them a common choice in the design of industrial steel structures, ensuring they can efficiently manage the demands of industrial environments while maintaining safety and operational efficiency.

Understanding the advantages of pinned supports can help designers and engineers select the most appropriate support type for specific projects, ultimately leading to more robust, safer, and more cost-effective industrial steel structures.