Experimental study of moment sharing in multi-joist timber-concrete composite floors from zero load up to failure
Experimental study of moment sharing in multi-joist timber-concrete composite floors from zero load up to failure
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DOI：
10.1016/j.conbuildmat.2019.07.137
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发表时间：
2019-11
影响因子：
7.4
通讯作者：
J. Mudie;W. Sebastian;J. Norman;I. Bond
中科院分区：
文献类型：
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作者：
J. Mudie;W. Sebastian;J. Norman;I. Bond
多托梁木-混凝土组合楼盖的T形截面必须按支座剪力和跨中弯矩的极限承载力进行设计，而支座剪力和跨中弯矩均受横向分担的影响，但影响程度不同。以前的实验工作只研究了支承反力分担和正常使用荷载。目前的实验研究建立在这一现状的基础上，通过量化也力矩共享，通过应变计布局在四分之一跨和中跨，沿着与反应共享通过负载传感器在支持的多托梁TCC样本，在整个负载范围内，直到失败。使用钢丝网连接器粘合到硬木层压单板木材托梁，并接近几何相似的真实的建筑TCC地板最近在伦敦建成，是新的功能的标本。结果表明，跨中弯矩和反力分担均随荷载呈非线性变化，但在未开裂、开裂和连接延性状态之间的进展中，它们之间的方式明显不同（观察到它们之间的差异高达近20%）。在这种方法中，力矩共享的可靠评估取决于记录的应变的质量。因此，应变数据被证明是高质量的，通过将这些数据转换为内部应力合成，然后发现满足纵向平衡。它的结论是，这种应变计布局是有用的，为今后的工作，旨在建立一个数据库的横向共享的时刻在TCC。
The critical T-sections of multi-joist timber-concrete composite (TCC) floors must be designed at ultimate for support shear force and midspan moment, both of which are influenced by transverse sharing, but to different extents. Prior experimental work has investigated only support reaction sharing and only up to serviceability loads. The present experimental study builds on that status quo by quantifying also moment sharing, via strain gauge layouts at quarter-span and midspan, along with reaction sharing via load cells at the supports of a multi-joist TCC specimen, over the entire load range up to failure. Use of steel mesh connectors bonded into hardwood laminated veneer lumber joists, and near geometric resemblance to a real building TCC floor recently built in London, were novel features of the specimen. The results show that midspan moment and reaction sharing both vary nonlinearly with load, but in distinctly different ways from each other (with up to almost 20% difference observed between them), in the progression between the uncracked, cracked and connection ductility regimes. In this approach reliable assessment of moment sharing depends on the quality of the recorded strains. Accordingly, the strain data were shown to be of high quality by converting these data to internal stress resultants that were then found to satisfy longitudinal equilibrium. It is concluded that this strain gauge layout is useful for future work aimed at building a database of transverse sharing of moments in TCCs.