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Building Dimensions | | | 12-50% Cost saving for long span steel building |
Fabrication | - Members fabricated in a controlled environment.
- Precise fabrication.
| - Fabrication done on site.
- Requires building the reinforcement cage and shuttering work prior to pouring.
| 90% saving in fabrication time on site. |
Delivery and Logistics | - Can be delivered anywhere in the world.
- Can be properly sequenced.
| | Capital Investment saving. |
Erection Time | - Fast erection. Virtually no idle time
| - Slow erection and time consuming.
- Pouring should take place in limited amount of time. If exceeded, the concrete quality may be jeopardized.
- The contractor will have to wait for the previous cast to harden (14-28 days) before being able to cast another batch.
| 50% saving in construction time. |
Industrial Applications | - Can easily handle equipment such as multiple cranes within building.
- Sways can be controlled.
- Precision can be achieved during installation.
| - Heavy equipment usage such as cranes is limited.
- To solve precision problems, contractors use steel I beams and platforms in concrete buildings.
| Saving on maintenance cost. |
Quality | Quality of steel is guaranteed because: - It is a homogeneous product.
- Pieces are tailored according to shop drawings.
- Precise machinery is used for fabrication.
- It is fabricated under shop control.
- Quality is not affected by weather conditions
| Many factors lead to quality deterioration: - Concrete is not a homogeneous product
- Concrete mix ingredient ratios are difficult to maintain.
- Quality of water used may vary.
- Weather conditions .
- Labor experience in pouring.
- Adequate use of vibrators.
- Using proper curing methods.
- Concrete shrinkage.
- High manpower count may weakan control.
| Less time is spent to maintain steel quality. |
Cost | - Low man power count needed.
- Erection cost is low at site
| - Construction cost is high at site
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Modulability & Scalability | - Can change a section of the building or even cancel a section with controlled effort and with little effect on structure stability and functionality.
- Expansion is easy. Longitudinally expansion is about adding more bays and connecting the secondary members and the sheeting to the old building.
| - Needs a lot of planning and has usually major consequences. Might be even impossible.
- To expand, the contractor has to build a new structure with foundations, columns and might have to break part of the old structure in order to expand it.
| Lower modification cost. |
Error Modification | - Easy to modify on site, even after erection.
- Modification can be done by cutting, welding or attaching steel pieces.
| - Have to break concrete if modification is necessary.
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Consistency and Reliability | - Strength is assured from design.
- Steel properties are stable with time.
| - Strength cannot be guaranteed without testing.
- Concrete properties may change over time and environmental conditions
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Seismic Effect | - Ductility of steel provides flexible behavior under seismic loads. Light Steel structures minimize the seismic effect on the structure.
- Steel is heavier than concrete but is 18 times stronger. A steel member can hold 6 times its own weight.
| - Poor flexibility under seismic loads. Heavy structures maximize the seismic effect on the structure.
- Heavy self weight. Large portion of concrete strength consumed to resist effect of its own weight.
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Ductility | - Show signs of failure when overloaded.
- Gives chance to fix the problem.
| - No warning signs.
- May result in disastrous collapse.
- Steel reinforcement is used to prevent brittle failure.
| Steel building requires less costly safety measures. |
Environment | - Steel is fully recyclable. Steel recycling technology is mature and standardized.
- Recycled steel results in better quality than Iron Ore.
| - Shy trials have been done on recycling of concrete.
- No standards adopted.
- Quality Problems.
- Almost zero residual value
| Steel residual value depends on steel process |