The Long Term Performance Of Skew Integral Bridges

Four types of integral bridges were modelled using the Midas Civil software; analysis of the results in terms of displacement, deflection, moments and torsion were considered. Creep and shrinkage, traffic and temperature loadings are taken into account. Skew angles were increased and sizes of abutments varied. The skew bridge had the majority of displacement on the short term of 40 days; a considerable percentage of displacement takes place on the long term up to 25%. The abutment angle affects the displacement of the skew bridges; the abutment with the acute angle had horizontal displacement of 27.2 mm while the abutment with the obtuse angle had less horizontal displacement of 13.2 mm on the long term when the abutment size is 0.5 m. For deflection, skew bridges has more deflection than the square bridges. Increasing the skew angle, the deflection increases. On the long term, it was discovered that about 5% of the deflection takes place. Comparing the result of the skew to the square bridge, the 8.60 bridge had 73% displacement more than the prestress bridge and 44.5% more than the non prestress bridge. The 130 skew bridge has higher deflection comparing with the non-prestress and prestress respectively. There were hogging moments because of the traffic loading that was considered during the modelling of the bridges. Normally, without a skew angle, the deck will act like it was simply supported with positive moments (sagging). The greatest sagging moment occurred in the non prestress 13o skew bridge deck with a magnitude of 6499.77 k Nm on the long term while the hogging moment has -1157.1 k Nm on the obtuse angle side of abutment. When the skew angle was increased, hogging moments increased as well. According to (Eugene, 1999), large skew angle correspondingly bring about great end hogging moments nearing wl2/12.