存梁时间对拼宽T梁桥运营期主梁线形的影响

Influence of Main Beam Geometric Shape During Operation of Widened T-Beam Bridge Based on Beam-Preserving Period

为研究存梁时间对拼宽桥主梁线形的影响,基于有限元法建立了三跨拼宽T梁桥有限元模型,分析了拼宽桥运营一段时间后在收缩徐变作用下的竖向、横向及纵向变形.研究结果表明:在考虑收缩徐变对拼宽桥线形的影响时,新旧桥梁的运营时间长短对主梁线形的影响较小,主要由存梁时间控制;拼接处的新旧梁位移差应予以控制,避免过大位移差引起的开裂风险;存梁时间过短对运营期的主梁线形不利,建议拼宽用新梁的存梁时间取6个月以上,最低不得少于3个月.

In order to study the influence of the beam-preserving period on the geometric shape of the main beam of the widened bridge,a finite element model of the three-span widened T-beam bridge was established based on the finite element method,and the vertical,transverse and longitudinal deformation under the action of shrinkage and creep after the operation of the wide bridge was analyzed.The results show that when considering the influence of shrinkage and creep on the shape of the wide bridge,the operation time of the new and old bridges has less influence on the main beam geometric shape,which is mainly controlled by the beam-preserving period;the displacement of the new and old beams at the joint should be controlled.To avoid the risk of cracking caused by excessive displacement difference,the small beam-preserving period is not good for the main beam geometric shape during the operation period.It is recommended to use the new beam for more than 6 months,and the minimum is not less than 3 months.