Study On The Seismic Performance Of SWFC Continuous Rigid Frame Bridge

Financed by the construction technology projects of Ministry of transportation entitled with “Application study of SWFC composite structure for continuous rigid frame bridge in Tibet”(Project number: 2013 318 J15 390),this paper has deeply studied the seismic performance of SWFC continuous rigid frame bridge which proposed by research group,and the main research work includes:(1)The SWFC composite structure has introduced,which set flat steel plate in the tensile region,collocated ribbed steel webs at the tensile surface,used steel fiber reinforced concrete with high content at the tensile bridge deck pavement,it has the advantages of simple construction and higher crack performance.(2)Parametric analysis has been conducted for the middle-small span continuous rigid frame bridges,the results indicate that internal force of piers in both the axial direction and transverse direction was decreased with the increase of the piers height,the displacement of the pier and the bridge decks was enlarged with the increase of the piers height;the internal force and the displacement in transverse direction of the bridge were decreased with the increase of the horizontal radius in transverse direction of the bridge,but in the axial direction,the internal force and the displacement were reduced with the decrease of the radius,because of the energy consumption caused by curve radius.Internal force and the displacement of high piers in the axial direction were decreased with the increase of the height difference of the piers,on the contrary,the short piers were increased with the increase of the height difference of the piers;when the tie beam was been set to the double-column pier,the displacement in the axial direction has a large increase,a small change in the horizontal radius,but the tie beam should not be too large when the tie beam is necessary to double-column pier.(3)A modeling method of SWFC composite structure has explored,in the model,the section was divided into three materials which were steel plate,steel fiber reinforced concrete and composite concrete,the composite concrete was divided into different parts by different reinforcement ratios,and obtained the unified constitutive of each parts by using the previous research results,this modeling method can conveniently and rapidly analyze the structure which are similar to the SWFC composite structure.(4)The results of analyzing the SWFC composite structure show: under the E1 earthquake action of level 8 the reinforced region of the bottom of the TT beam segments in the middle span occurs cracks,the length of the cracks is almost 2/3 of its total length,and the width of the cracks is about 0.06mm;under the E1 earthquake action of level 9 the length of the cracks is almost 3/4 of its total length,and the width of the cracks is about 0.064mm;under the E2 earthquake action of level 9 the length of the cracks is almost 4/5 of its total length and the width of the cracks is about 0.07 mm,the remaining sections of bridge are in a state of flexible working.(5)The damage process of the SWFC composite structure under the E2 earthquake when the peak acceleration reaches 0.6g shows: the plastic hinge appears firstly on the top of the outside pier that is also near to the abutment,then on the top of the inner pier,and the bottom of the pier,it appears at last.