Civil Engineering – Concrete Design Coursework

You are asked to design a simply-supported reinforced concrete bridge beam to span 20m, with a top flange width of 1m. You may choose any form of cross section you like, varying along the length of the bridge beam in any way you like, but you need to attempt to minimise the cost and/or carbon footprint of the structure. The bridge beam will be required to carry its own self weight (to be factored by 1.35 at the ULS), a permanent super-imposed dead weight of 4kN/m (to be factored by 1.35 at the ULS) and a maximum live load of 30kN/m (to be factored by 1.5 at the ULS). You will need to make all sorts of assumptions to achieve a sensible design. State these clearly and boldly. As part of your design, you should assume that any formwork system is available to you in order to produce a curved soffit. Any other part of the cross section should be assumed NOT to vary. Thus, do not attempt to use fabric as the former for the whole cross section, but rather merely assume that the overall depth of the cross section can vary. You should consider ultimate flexural capacity and ultimate shear capacity only. Do not consider deflections and cracking. Therefore, this implies that you should not be considering prestressed concrete, but rather reinforced concrete. Sketch the final longitudinal section of the beam (showing the overall depth of the beam at the supports and at mid-span), the cross section of the beam at mid-span, and the cross section of the beam at 1m from a support. In all sections, you should show reinforcement layouts and details (bar sizes and spacings). You should also sketch how the ends of the beam are to be supported in reality. You should use Eurocode 2 as the basis of all technical specifications. You may assume that the placement of C30 concrete costs £400/m3 (including falsework, formwork, casting, compaction, curing and striking) and for C60 it costs £600/m3, with linear interpolation or extrapolation of these figures being possible. Steel reinforcement costs £3 per kg (including cutting, bending and tying). Find the cost of your beam. Assume that C30 concrete has a carbon footprint of 400kg/m3 and for C60 it is 600kg/m3. Again, you may linearly interpolate or extrapolate these figures to suit. Steel reinforcement has a carbon footprint of 2kg per kg. Calculate the carbon footprint of your beam. The report is to be one double-sided A3 sheet (the equivalent of four A4 pages in length). On the left hand side of the front page, your report should show hand sketches of all three sections (one long and two cross sections), the total cost of your beam to the nearest £100 and the total carbon footprint of your beam to the nearest 100kg. Ensure that these two numbers are easily visible and bold. You should use the rest of the A3 sheet (equivalent of three A4 pages) to provide brief Eurocode-driven calculations to back up the design sketches and cost/carbon footprint on the front page. Use the template overleaf for the front left hand sheet, as shown schematically in the figure on the last page of this brief. Please, please stick to this format by using one double-sided A3 sheet as intended and do not reduce the template size overleaf to less than A4 size.