Transverse temperature difference of steel girder in a long-span suspension bridge

Temperature distribution of bridge girder cross-section is generally non-uniform. The vertical temperature difference has been widely investigated and specified in design codes. The transverse temperature difference (TTD) is usually smaller than the vertical one for most types of bridge, especially for concrete bridges. However, particular types of bridge may also experience significant TTDs, which may result in plan bending of the main girder and generate plan rotations at the bearings. This paper investigates the transverse temperature distribution of the Humber Bridge, a long-span suspension bridge with steel streamlined girder in the UK, through numerical and field monitoring exercises. The long-term data measured from thermal sensors on the deck show that the Humber Bridge experiences significant TTD, particularly in summer. To study the detail of TTD, a two-dimensional finite element model of a typical section of the box girder is constructed, in which several new elaborate approaches are developed for achieving an efficient and effective heat-transfer analysis. The numerical results in different seasons agree well with the field measurements and verify the significant TTD of this bridge. Parametric studies with the established numerical model show that deep upper webs play a critical role in TTD.