钢筋桁架混凝土叠合板桁架吊点力学性能试验研究

Experimental study on hoisting point of composite slab with lattice girders

为解决钢筋桁架叠合板在吊装时钢筋桁架兼作吊点无据可依的问题,进行了钢筋桁架吊点的力学性能试验,主要参数包括桁架腹杆钢筋类别、桁架埋深、锚固措施和起吊角度。研究表明,钢筋桁架吊点的破坏模态为多阶段破坏,主要特征包括焊点断裂、钢筋断裂和混凝土锚固破坏。腹杆钢筋为热轧带肋钢筋时,吊点破坏主要为加载点处焊点断裂或混凝土锚固破坏,腹杆钢筋为冷轧光面钢筋时,吊点破坏主要为腹杆钢筋断裂;桁架埋深35mm或45mm,有无锚固钢筋对吊点破坏承载力影响不大;60°加载时,两侧腹杆钢筋受力不均匀,吊点承载力较之90°加载时低。根据试验结果给出了钢筋桁架吊点的承载力标准值和施工安全系数建议值,可供工程应用参考。

Mechanical test of composite slabs with lattice girders is carried out, researching the mechanical property of lattice girder when used as hoisting point. This test supplies basis for engineering application. Main parameters include diagonals’ type, embedded depth of lattice girder, anchor measures and lifting angle. The results show that, the lattice girder hoisting point fails in several stages, the failure modes include welding spot failure, fracture of diagonals and concrete failure of anchor zone. When using hot-rolled diagonals, hoisting point mainly fails on welding spot failure or concrete failure of anchor zone, while using hard drawn plain diagonals, hoisting point mainly fails on diagonals’ fracture. Embedded depth and anchor measure affects slightly. When specimen loaded in 60 degrees, the diagonals stress is asymmetrical and provides lower bearing capacity comparing to the specimens loaded in 90 degrees. Design suggestions are provided according to testing results, which can be used for engineering.