G550高强冷弯薄壁槽钢受弯构件力学性能与设计方法

为了研究高强冷弯薄壁槽钢受弯构件的力学性能和设计方法,对3种板件加劲形式的G550高强冷弯薄壁型钢槽形截面受弯构件进行了试验研究和有限元参数分析。结果表明,板件加劲形式对高强冷弯薄壁槽钢受弯构件屈曲模式和受弯承载力有显著影响,翼缘V形加劲比腹板V形加劲能够更有效地提高构件抗弯承载力,构件抗弯承载力的变化规律与屈曲模式有关。根据有限元参数分析结果,在已有直接强度法基础上回归出适用于高强冷弯薄壁槽钢受弯构件的直接强度法修正公式。     

圆钢管混凝土轴压长柱极限承载力的稳定系数法

为完善圆钢管混凝土轴压长柱极限承载力的计算理论,对比分析了中国国家标准GB 50936-2014和CECS 28：2012中轴压短柱极限承载力的N₀计算公式,并把GB 50936-2014中基于套箍系数的N₀计算公式改写成统一的形式,提出了基于正则长细比的轴压长柱的稳定系数计算式,并通过36个试件的对比,对计算式的精度和适用范围进行了分析。研究表明,现行国标GB 50936-2014中基于套箍系数的N₀计算公式更为精确,基于N₀计算公式和本文的稳定系数,可以计算得到更为精确的轴压长柱的极限承载力。     

偏心受压冷弯薄壁槽钢的卷边角度优化设计

为了使得钢结构的性能与用钢量比达到最优,前人对槽型钢的截面尺寸优化进行了较为充分的研究。但是,涉及卷边角度的优化特别是偏心受压工况下的优化分析却很缺乏。以Yao-Teng偏心受压计算公式,结合遗传算法,以冷弯卷边槽钢柱偏心受压为例,将槽钢卷边角度与偏心距作为设计变量,寻找在不同偏心距受压情况下,达到最大畸变屈曲临界应力的卷边角度。基于有限条分析程序,对两端简支与两端固支情况下不同截面尺寸构件的畸变屈曲临界应力进行了计算分析,最终得出不同偏心距受压下统一的最优卷边角度。为了方便工程设计人员设计时参考,建议卷边角度统一取为100°。     

Contrast Analysis of Mechanical Behavior of Confined Concrete with Stirrups and CFRP Under Axial Compression

Aiming at confined concrete with stirrups and carbon fiber reinforced plastic(CFRP) respectively, the major influence factors of mechanical behavior of confined concrete under axial compression were studied based on reported experimental data. The equations for calculating the peak stress, peak strain and ultimate strain were proposed respectively for confined concrete with stirrups and CFRP. Contrastive analysis shows that the behavior of confined concrete with stirrups is better than confined concrete with CFRP in low characteristic value, whereas the conclusion is contrary in high characteristic value.     

Probability Analysis of "Strong Beam and Weak Beam" and Axial Compression Ratio in RC Frame

In the view of reliability calibration, this paper analyzes the probabilistic sense of the provisions of "Strong Column and Weak Beam' and axial compression ratio in aseismic criteria (GBJ 11 89), which demonstrates that there is much difference between different aseismic ranks of RC frame. The authors suggest that it is possible to make axial compression ratio larger by adjusting the moment capacity ratio between column and beam. Finally, the direction and method of further studies are proposed.     

The Experimental Study on Size Effects on Axial Compression Performances of Reinforced Concrete Column under Repeated Load

The size effects on axial compression performances of reinforced concrete column under repeated load are needed. Specimens were designed and tested in accordance with the relevant similarity, whose geometric dimensions are: 400 mm×400 mm×1 200 mm, 600 mm×600 mm×1 800 mm and 800 mm×800 mm×2 400 mm. The result of the experiment, the failure characteristics, crack development process, strength, peak stress, peak strain and stiffness of various specimens were comparatively analyzed. The results show that, within size range of this test, size effect exists on performances of columns.     

高强钢绞线网加固混凝土粘结性能试验研究

通过高强钢绞线网聚合物砂浆加固层与混凝土结构的剥离破坏试验,对加固层与混凝土界面的剥离破坏特征进行了研究。探讨了单侧加固、植筋加固及U型加固等不同的加固方式对加固层抗剪承载力及抗剪强度的影响。试验结果表明,采用U型加固等增加粘结面积的方式能有效提高加固层粘结面抗剪承载力,但同时会削弱加固层的抗剪强度,而在界面上植入抗剪钢筋后,能同时提高聚合物砂浆加固层的抗剪承载力及抗剪强度。根据试验结果,提出了最小植筋率的建议值。     

Experimental Analysis on Behavior of Cold formed Steel Box Built up Section Columns under Axial Compression

17 specimens of cold formed steel box built up setion columns were tested under axial compression load. The section forms were divided into two categories: A and B. Load displacement curves and failure characteristics of specimens were obtained. The test results are compared with the caculated results according to “effective ratio of width to thickness” in code of “Technical code of cold formed thin wall steel structures” (GB 50018－2002), “effective section method” and “direct strength method” in AISI specification. The results show that: the failure characteristics of LC and MC series columns are overall flexural buckling, while SC series columns are local buckling and ends confined damage. The ultimate bearing capacity of B categories section columns is three times as great as that of A categories section columns, so it has the effect of “1+1＞2”. The results calculated according to “GB50018” and AISI specification are much conservative for LC series columns of A categories section, while in agreement with test results for MC and SC series columns. For B categories section columns, the calculated results are non conservative for LC and MC series columns, while conservative for SC series columns.