Presentation on theme: "Reinforced Concrete VS Steel"— Presentation transcript:
1 Reinforced Concrete VS Steel (1) MaterialsReinforced ConcreteVS Steel
2 Materials Reinforced Concrete Advantage good resistance to weather & chemical, and good sound and thermal insulationthe structure system is more rigid, thus, less severe problem associated with sway deflection, floor vibration, and local column bucklinghigher fire resistanceminimal maintenance is requiredmaterials required to make concrete are readily available in the local market, thus no pre-ordering is necessarylocal contractors are firmly familiar with RC constructioncan be cast into any versatile shape, thus, allow more flexible designfairly tolerable on last minute changes from Client and Architectwaterproofing can be easily applied with different degree of waterproofingcan produce a good finished surface, thus, no painting is necessary
3 Materials Reinforced Concrete Disadvantage general heavier and hence more expensive foundation resultedspecial care must be taken to ensure esthetic appearance against cracks induced by creeping and shrinkage effectsintensive amount of falsework and shuttering are requiredeasily affected by weather condition, this will prolong construction time
4 Materials Steel Advantage fast construction, weather independent flooring can be cast at the same time where formwork are provided by un-propped corrugated steel deckinglightweighted, thus, less expansive foundation can be designed (i.e. shallow foundation.)assembly is simple, since all members can be pre-fabricated prior to delivery to sitestructure tends to be shallower in structural depth, thus, more space will be provided for service routingwith high strength to weigh ratio, suitable for long span construction.
5 Materials Steel Disadvantage Long pre-ordering and delivery time would be required since majority members are to be import from overseasEarly decision on member size & connection details are required so as to allow for ordering and shop drawing preparation.Steel members require special treatment and protection on fire & corrosion.Special surface treatments are needed:Low cost – Sprayed System (Mineral fibre sprayed systems, Vermiculite/gypsum/cement system)External System (Mineral fibre boards/batts, Vermiculite/gypsum boards, Plasterboard)Preformed SystemIntumescent CoatingsWater or Concrete filled structural hollow sectionsConcrete casings
6 Materials Steel Disadvantage frequent maintenance is required skilful labors are required for fabrication, erection, and weldinglarge area on site is required for storage of structural member prior to erectionsensitive to temperature change and vibrationsteel members will deflect appreciably under total load, needs pre-camberingfabrication needs heavy plant and crane
7 (2) Structural Systems Vertical Load Supporting System Lateral Load Supporting System (x & y directions)
8 Structural Systems Cantilever without back span Columns do not vertically alignToo long cantileversCantilever from column without back spanHeavy loading on long span transfer beamLong Slender Columns
9 Floor Supporting Systems (3) Structural FormsFloor Supporting Systems
32 (4) ReferencesFuller Moore, Understanding Structures, Boston, WCB/McGraw-Hill, 1999.Institution of Structured Engineers, Manual for the design of reinforced concrete building structures, London, the Institution, 1985.Institution of Structured Engineers, Manual for the design of steelwork building structures, London, the Institution, 1989.Ove Arup & Partners, Structural scheme design guide, London, Arup Research & Development, 1998.