2015年新实施的《公路工程技术标准》（JTG B01－2014）将公路－Ⅰ级车道荷载集中荷载标准值由180～360 kN增加到270～360 kN。为指导新标准下桥梁设计，以13，16，20，25，30 m标准跨径的预应力混凝土T形简支梁桥为研究对象，对比分析车道荷载增加后边梁和中梁跨中活载弯矩、作用基本组合值、作用短期组合值、作用长期组合值的变化；对边梁和中梁预应力钢绞线和受拉区普通钢筋进行对比计算，给出新荷载标准下需增加的配束要求。研究表明：活载引起的边梁跨中弯矩最大增幅为27％；作用基本组合、短期组合、长期组合的最大增幅分别为22％、18％和14％。新标准下所需的预应力钢束和普通受拉钢筋数目均增大，5种跨径下单片边梁分别增配φs 15．2预应力钢绞线3束、3束、2束、1束、1束，受拉区普通钢筋分别增配2根φ22、3根φ22、1根φ25、1根φ25和0根φ25；单片中梁分别增配φs 15．2预应力钢绞线2束、2束、2束、1束、1束，受拉区普通钢筋分别增配3根φ22、2根φ22、0根φ25、0根φ25和0根φ25。%In the new Technical Standard of Highway Engineering (JTG B01‐2014)which goes into effect in 2015 ,the standard range for eccentric load of Grade Ⅰ traffic lane load is increased from 180~360 kN to 270~360 kN .To guide the bridge design under new standard ,the simply‐supported prestressed concrete T beam bridges with spans of 13 ,16 ,20 ,25 ,30 m respectively were taken as the study objects ,to comparatively analyze the load variation of side spans and the central span ,including the midspan deflection induced by live load ,the basic combined load value , the short‐term combined load value and the long‐term combined load value under the action .The amount of prestressed steel strands in the side spans and the central span and that of the common reinforcement in the tensile area were calculated and compared ,and the amount of reinforcement that should be added under the new load standard was suggested .The results of the study indicate that the midspan deflection in the side spans induced by live load is increased by 27% at maximum , and 22% ,18% and 14% at maximum under the action of basic combined load ,short‐term com‐bined load and long‐term combined load ,respectively .In the new technical standard ,the pres‐tressed steel strands and common tensile reinforcement required are all increased .In the beams with the aforementioned five span lengths ,the number of the φs15 .2 prestressed concrete steel strands added to a single side span beam are 3 ,3 ,2 ,1 ,1 ,w hile the amount of common reinforce‐ment added to the tensile areas are two reinforcement of 22 mm diameter ,three of 22 mm diame‐ter ,one of 25 mm diameter ,one of 25 mm diameter and none of 25 mm .In a single central beam , the number of the φs15 .2 prestressed steel strands added under the five span lengths are 2 ,2 ,2 , 1 ,1 ,w hile the common reinforcement added to the tensile area are three reinforcement of 22 mm , two of 22 mm ,zero of 25 mm ,zero of 25 mm and zero of 25 mm .
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