Why railway stations have roof trusses instead of concrete reinforced slabs?
Most single roof structures, not only railway stations, but also industries, stadiums are in steel.
- The roof loads being very light, the required steel sections are not heavy and in such a scenario, they will prove to be less expensive than concrete.
- Concrete is comparitively a recent phenomena. In fact till around 1970’s, it was a scarce and controlled item. Whereas steel has been used since long…in fact, most of the highrises is USA were constructed using steel. And this could also have played a part as stations in USA were mostly in steel.
- The design of the truss system is standardised. The same sections are used in all the stations. This would help in economising as sections can all be prepared in workshops and transported to site…again railways being the transporter, there would be minimum cost attached to it.
- Rainwater pipes and electrical cables can be can be run between truss members….. so no cutting of beams or hanging of pipes/trays below beams.
- For incremental growth, eg fixing of display boards, etc., easier to do it on steel members than on concrete members.
- Quality control of concrete production varies from site to site and contractor to contractor. Given Railways stringent quality controls, it would be impossible to maintain the quality control on so may sies and in remote locations. Steel fabrication can be done in centralized workshops under strict quality control and in house design teams leading to efficiency.
- Leakages etc can be attended to quickly. Incremental expansion can be done conveniently
These are just a few of the reasons……