STRUCTURAL ANALYSIS AND DESIGN OF BOX CULVERT ALONG ISUANIOCHA/MGBAKWU ROAD USING EURO CODE 2

Abstract

This study was conducted to evaluate the structural reliability of EC2 in the analysis and design of hydraulic structures. The structural analysis and design of single and triple cell box culvert along Mgbakwu/Isuaniocha road using EC2, focuses essentially on load assemblage and estimation, calculation and analysis of moment using hardy cross method of moment distribution, calculation of shear force, design and provision of area of steel required. From theloading analysis, the ultimate design load for top slab, vertical walls and bottom slab are 78.07KN/m, 41.88KN/m and 140.69KN/m, 122.79KN/m, 48.6KN/m and 159.6KN/m when both culverts is empty and 12.37KN/m, 93KN/m and 99.8KN/m, 10.69KN/m, 76.5KN/m and 41.99KN/m when both culvert is full. The fixed end moment and free end moment generated for the structural members of the single and triple cell box culverts are 27.84KNm, 58.61KNm and58.61KNm, 76.51KNm, 25.43kNm and 90.08KNm, 189.2kNm, 12.81kNm and 246.2kNm, 283.8kNm, 13.31km and 369.34kNm respectively while the design moment are 48.67KNm, 58.61KNm and 58.61KNm, 154.83kNm, 178.85kNm and 190.49kNm respectively. The maximum shear forces are 53.96KN, 128.69KN and 63.77KN, 63.05KN, 529.3KN and 73.85KN respectively. The design suggest that minimum area of steel of 1200mm2 was required for allstructural members (Top slab, Vertical walls and Bottom slab) of the single cell box culvert and area of steel provided was 1340mm2 while the triple cell box culvert suggested an area 1600mm2 as the area of steel required for all structural members, 1800mm2 as area provided for top slab, 2090mm2 as area provided for the two vertical walls and bottom slab respectively. The type, size and spacing of reinforcement specified by the design for all structural members are Y16@ 150mmc/c U-bars as main bars and Y12@ 200mmc/c as distribution bars in both faces for the single cell box culvert and Y20@ 150mmc/c U-bars as main bars and Y12@ 150mmc/c as distribution bars in both faces for the triple cell box culvert respectively. The bar bending schedule prepared indicate that seventy-five length of Y16 was required as main bars and forty length of Y12 was required as distribution bars for the single cell box culvert and three hundred and seventy-two length of Y20 was required as main bars and one hundred and fifty-one length of Y12 was required as distribution bars for the triple cell box culvert. The shear design carried out for the critical shear generated (128.69KN and 529.3KN) was satisfactory as the designconcrete shear stress exceed the design shear stress in magnitude. The study encourages the use of EC2 in the design of concrete structures as it is logical, organized and structurally reliable, this code is gaining more credence globally and should therefore be adopted by Nigerian Engineers.