Study On Entirety Performance For Multi-beam Concrete T-shaped Section Beam Girder Based On The Whole Process Of Fire

In our country, there are many rivers and lakes and gulves need to cross that lead totremendous achievement in bridge building, with the rapid development of transportationinfrastructure.Oil tank cars and big trucks crossed bridge and oil tankers passed under bridgeare potential sources of ignition.Especially for the fire caused by oil tank cars and oil tankersis a great threat to the bridge structure. Now, research on the fire resistance for bridgestructure is at the starting stage, more research work for bridge fire resistance need to do, andstandard of fire-resistant designation need.Based on the project which named ‘research on catastrophe mechanism andreinforcement technology and safety evaluation for bridge structure esposed to fire.’.(GrantNo.2011318812970) and sponsored by Research Fund Ministry of Transport of China, andthe project which sponsored by Research Fund for the Central Universities of China (GrantNo. CHD2011TD010),fire temperature rise model is established and fire scenarios is designed.Material properties and temperature rise curve are comprehensively putted into consideration,space deformation and stress distribution of multi-beam concrete T-shaped section beamgirder are studied under condition of different fire mode. Fire-resistant performance ofstructure is revealed.The main research contents are as follows:(1)Based on thermal conduction matrix and boundary condition, the basical calculationmethod and step for temperature field is given.Then,temperature rise cauve of HCM isanalysed, underbridge fire model is set up,and fire scenarios is desgined.Meanwhile,thermalproperity of materials adopted for multi-beam prestressed concrete T-shaped section beambridge is studied.(2) Temperature distribution and time-dependent rise rule of key point for multi-beamprestressed concrete T-shaped section beam bridge is analyzed,and the distribution rule ofshear lag under the symmetrical fire model is disclosed.(3) At last, Change rule of midspan Transverse deflection Under the dead load in theearly and late stage of extending fire is calculated. And the deforming envelope diagram forthe beam exposed to different fire mode is drew.