加拿大铁杉正交胶合木弯曲性能预测与评估

Prediction and Assessment of Canadian Hemlock CLT Bending Performance

为了对正交胶合木(CLT)的弯曲性能开展有效预测与评估,验证CLT板件弯曲性能预测值的可靠性,采用自由梁横向振动法,对加拿大铁杉锯材顺纹弹性模量进行动态测试与质量分等;采用悬臂板横向振动法动态测试铁杉锯材的横纹剪切模量和弹性模量;将分等后的铁杉锯材制成足尺CLT楼板、墙板用板材,并采用四点弯曲法静态测试CLT板材的弹性模量值;然后将锯材顺纹弹性模量、横纹剪切模量和弹性模量实测值代入模型公式进行CLT板弯曲性能预测,并与CLT板材静态弹性模量实测值作比较分析。结果表明:CLT主强度方向弹性模量预测值为11 222 MPa,实测值为11 312 MPa,CLT板材的弯曲弹性模量的预测值与其实测值决定系数为0.887,具有较强的相关性;用CLT板材的预测值模型公式评估其弯曲性能指标,具有应用上的可行性和可靠性;铁杉制成的CLT板材弯曲性能达到CLT楼板、墙板等工程用的等级要求。

In order to effectively predict and assess the bending performance of CLT, and to reliability prediction verification of CLT plate bending, dynamic testing and grading are made into full scale CLT slabs and wall panels according to elastic modulus parallel to grain, by the transverse vibration free beam method used in this paper; the transverse shear modulus and elastic modulus of the fir lumber are tested by the dynamic test of the transverse vibration of the cantilever plate and the four-point bending method; the elastic modulus parallel to grain, the transverse shear modulus and the elastic modulus of the lumber are substituted into the model formula of the CLT plate, and the flexural properties are predicted and compared with the measured values of the CLT plate. The predictive value of the flexural modulus of the CLT sheet is 0.887. The results show that the prediction of the bending elastic modulus of CLT sheet value and measured value strong correlation, prediction of elastic modulus is 11 222 MPa, and the measured value is 11 312 MPa; the bending model formula to assess the performance indicators for the prediction of CLT sheet value, has the feasibility and reliability of application; The bending performance of CLT plate is up to CLT floor, wallboard and other engineering requirements.