大宽跨比T梁桥的改进空间梁格算法

由于目前“G-M法”（比拟正交异性板法）计算主梁内力较复杂繁琐,为了更快速精确的计算大宽跨比,多横隔梁以及主梁较为密集的T梁桥主梁内力效应,提出了基于受压翼板有效宽度的大宽跨比T梁桥改进空间梁格算法。该方法通过有限元软件建立空间梁格模型,基于T形梁受压翼板有效宽度原理,精确考虑横隔梁与主梁顶板协同受力完成荷载横向传递时的横桥向横隔梁翼板有效宽度,对梁格模型中的横隔梁进行横隔梁-桥面板的截面等效换算,保证沿桥横向翼板内的应力分布均匀,模拟实桥横向联系。分别采用“G-M法”和本文方法计算分析桥宽20 m、24 m,跨径20 m、28 m、35 m的4种算例的装配式简支T梁桥主梁跨中弯矩,对比分析发现：1）改进空间梁格法与比拟正交异性板法吻合较好,误差均在±5%左右,精度较高;2）改进空间梁格法相比“G-M法”无需复杂的插值和查表,只需要借助简单的有限元模型,能快速高效的对主梁结构内力进行计算,操作方便,效率高;3）改进空间梁格法对大宽跨比,多横隔梁以及主梁较为密集的T梁桥结构内力计算结果更可视化,更能精确直观的反应受力后的整体结构响应。

Improved Spatial Girder Algorithm of T-beam Bridge with Large Width to Span Ratio

Due to the current "G-M method" (The Orthogonal Plate Method)to calculate the internal force of the main beam is complicated and tedious. In order to more quickly and accurately calculate the internal force of the main beam that T-beam bridge has large width to span ratio, multiple transverse beam and dense main beams, an improved spatial girder algorithm of T-beam bridge with large width to span ratio that basing on effective width of compression wing plate is proposed. In this method, the spatial beam lattice model was established using finite element software. Then, the effective width of transverse bridge to transverse beam wing plate was precisely considered when the transverse load transfer was completed by cooperating force between transverse beam and main beam roof, based on the principle of effective width of compression wing plate of T-shaped beam. Finally, the equivalent conversion of the cross section between the cross section beam and the bridge panel was carried out in the beam lattice model, thus ensuring the uniform stress distribution in the transverse wing plate along the bridge, and the transverse connection of real bridge was simulated. The "G-M" method and the proposed method were used to calculate and analyze the mid-span bending moment of the prefabricated simply supported T-beam bridge with the bridge width of 20 m,24 m and span of 20 m,28 m and 35 m, respectively. The comparative analysis shows that:1) the improved spatial beam lattice method is in good agreement with the orthogonal plate method, the error is about ±5%, and the accuracy is high. 2) compared with the "G-M method", the improved spatial beam lattice method does not need complex interpolation and table lookup, but only the help of simple finite element model, which can quickly and efficiently calculate the internal forces of the main beam structure, with convenient operation and high efficiency; 3) the improved spatial beam lattice method is more visual for the calculation results of internal forces of T-beam Bridges with large width to span ratio, multiple transverse septum beams and dense main beams, and can accurately and intuitively react the overall structural response after stress.