Structural engineering - Essay Example

The analysis can be done either manually or using commercial software. This paper is aimed at expounding on the details of sub-frame structural design. For a span that is greater than or equal to two times the overall depth for simply supported span and greater than or equal to two and a half times the overall depth for continuous span, a beam is classified as shallow beam, otherwise it is a deep beam. Effective width (beff) = width of beam (bw) + Σ(0.2 times of half the centre to centre width to the next beam (0.2bi) + 0.1 times the span of zero moment (0.1lpi), with the sum of the latter not exceeding 0.

2 times the span of zero moment and lpi taken as 0.7 times the effective span of the beam). Design moment of beam (and slab) monolithic with its support providing rotational restraint should be that at support face if the support is rectangular and 0.2Ø if the support is circular with diameter Ø. But the design moment after reduction should not be less than 65% of the support moment. For a simply supported or continuous beam, the clear distance between restraints should be less than or equal to 60bc or 250bc 2/d if less; and for a cantilever with lateral restraint only at support, the clear distance from cantilever to support should be less than or equal to 25bc or 100bc 2/d if less where bc is the breadth of the compression face of the beam and d is the effective depth.

Usually the slenderness limits need be checked for inverted beams or bare beam (without slab) We can, as far as our building structures are concerned, roughly adopt condition 1 (Mild) for the structures in the interior of our buildings (except for bathrooms and kitchens which should be condition 2), and to adopt condition 2 for the external structures. Nevertheless, the “Code of Practice for Fire Resisting Construction 1996” should also be checked for different fire resistance periods (FRP).

So, taking into account our current practice of using concrete not inferior than