Structure Weight
Primary steel members are selected from standard hot rolled “I” section which are, in many segments of the members, heavier than what is actually required by design. Members have constant cross- sections regardless of the varying magnitude of the local (internal) stresses along the member length.
Secondary members are selected from standard hot rolled “I” or “C” sections, which are heavier.
Design
Each conventional steel structure is designed from scratch by the consultant, with fewer design aids available to the Engineer.
Substantial engineering and work is required on every project. Generalized computer analysis programs require extensive nput/ output and design alterations.
Extensive amount of consultant time is devoted to design and drafting, as well as co-ordination and review, often resulting in a significant expense.
As each project is a separate case, engineers need more time to develop the designs and details of the unique structure.
More complicated design, requiring extensive design and drafting time from consultants.
Delivery
Average 20 to 26 weeks.
Foundations
Extensive, heavy foundations required.
Erection Simplicity
The connections are normally complicated and differ from project to project, resulting in longer learning curves of erection for new projects.
Erection Cost and Time
Typically, conventional steel buildings are 20% more expensive than PEB. In most of the cases, the erection costs and time are not estimate accurately. Erection is slow and extensive field labor is required. Heavy equipment is often needed.
Seismic resistance
Rigid heavy weight structures do not perform well in seismic zones.
Overall Price
Higher price per square meter. Architecture
Special architectural design and features must be developed for each project, which often require research and thus resulting in much higher costs.
Sourcing and Coordination
Many sources of supply considerable: project management time is required to co ordinate suppliers and sub contractors.
Cost of Change Orders
Substitution of hot rolled sections, which are infrequently rolled by mills, is expensive and time consuming.
Change orders that are made, after hot rolled sections are shipped for fabrication, often result in redundancies to a lot of hot rolled sections, which ultimately result in more cost to the enduser.
Building Accessories
Every project requires special design for accessories and special sourcing for each item. Flashing and trims must be uniquely designed and fabricated.
Future Expansions
It would be difficult to obtain project records, after a long period of time. It is required to contact more than one party, involved in the project, to obtain accurate
information.
Future expansion would be more difficult and more likely costlier.
Safety and Responsibility
Components are custom designed for a specific application on specific job. Design and detailing errors are possible when assembling the diverse components into unique buildings.
Performance
Each building design is unique, so prediction of how components will perform together is uncertain.
Material which have performed well in some climates may not do so in other environments.
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