胶合木张弦梁弯曲性能试验及工程应用研究

Experimental research on flexural behavior of glulam beam string structure and engineering application

为了进一步研究胶合木张弦梁(BSS)的力学性能,进行了10榀花旗松胶合木梁(2榀普通胶合木梁(B),8榀的张弦胶合木梁)的抗弯试验研究。结果表明:张弦梁可改善普通梁的脆性破坏模式,使上弦木梁的受压性能得到有效发挥,破坏表现出塑性特征,极限承载能力提高3倍以上。张弦梁的极限承载力及刚度与跨高比成反比,与垂跨比成正比,与腹杆数量成正比。初始预应力水平对承载能力的影响不明显,仅对刚度有贡献。结构破坏时的延性需要综合考虑各项因素。结合一项设计完成的50.4 m跨胶合木张弦拱结构实例,阐述关键连接节点及预应力取值等问题,并对整体结构性能进行了分析。研究内容可为胶合木张弦梁理论及工程应用提供参考。

In order to investigate the performance of glulam beam string structures（ BSS）, ten specimensof douglas fir glulam beams （2 of ordinary glulam beams, 8 of BSS） were undertaken. The results indicate that BSS can improve the brittleness failure mode of ordinary beam, and the compression performance of the upper chord beam can be used effectively. The BSS behave mostly as the characteristics of plastic failure.The ultimate bearing capacities of BSS are increased by more than three times.The ultimate bearing capacity and stiffness are inversely proportional to thespan-to-depth ratio, but directly proportional to the sag-to-span ratio ,to the number of web members.The influence of the initial prestress level on the bearing capacity is not obvious, but contributes to the stiffness of the whole structure is important.The ductility of BSS should be considered from various aspects.Combined with a completed design, a arched glulam beam string structure with 50. 4 m span, the key connection, prestress and other issues, and analyze the overall performance of the structure were described. The results can provide reference for the BSS theory and engineering application.