高温后型钢混凝土T形柱力学性能的试验研究
发布时间：2018-07-21 19:18
【摘要】：型钢混凝土异形柱结构是把钢骨架埋入钢筋混凝土中的一种新型结构形式,因其具有良好的布置灵活性和优于普通混凝土柱的承载力及抗震性能,被广泛的运用于高层建筑中。随着高层建筑在现代建筑中占据越来越重要的地位,高层建筑的结构安全受到广泛的关注,各种灾害中火灾对建筑物的危害尤为严重。由于型钢柱的含钢率较高、受火面积大,因此高温下其承载力损失程度和危险程度也要高于普通混凝土柱,为了保护人身安和减少经济损失,同时也为了给火灾救援及后期修复工作提供一定的理论依据,有必要对异形柱火灾后的力学性能进行进一步研究。本文主要研究了型钢混凝土T形柱高温后的力学性能,主要工作及结论如下:本文设计了11根T形SRC柱,利用自制电加热炉进行了恒温条件下的四面受火试验,对高温后试件在不同设计变量和加载条件下(水平腹杆间距、含钢率、加载角、偏心距)进行力学试验研究,将相关数据进行了整理与分析,得到如下结论:(1)高温作用后,异形柱受高温区混凝土表面颜色变为灰白色,随恒温时间增加,局部呈现淡红色。柱子背部中间区段内出现细微裂缝,部分试件表面有粉状物质析出。各试件相同测点处升温趋势基本一致,越靠近T形柱表面的测点温度升高的越快。恒温时间3小时的各试件,截面温度场变化规律基本一致,理论上可以认为各试件经历相同高温时长后的损伤相同。600℃下恒温1h、2h和3h后,试件自由膨胀率分别为0.47%、0.67%和0.75%,各试件轴向变形量随恒温时长增加呈现线性增长规律。腹杆间距对试件最终的轴向变形量基本没有影响,试件最终的轴向变形量随含钢量增加而减小。(2)高温后轴心受压T形柱在荷载作用下的破坏过程和破坏形态与常温下试件基本相同。偏心受压构件破坏形态与轴压试件类似,但偏心受压试件初裂荷载和剥落荷载均有大幅度提前,最终的破坏形态表现为偏心受压一侧混凝土严重剥落,受压侧型钢屈服外露,另一侧出现水平贯通裂缝。常温下试件在破坏时,柱身裂缝明显少于经历过高温的试件,并且试件也维持了较好的完整性;经历过高温的试件在破坏时,柱身都产生了大量的裂缝,且主裂缝较宽,柱身破坏严重,变形也更严重。(3)常温下对比试件轴向刚度要明显大于受高温后的试件。受高温后的试件在相同荷载下的轴向变形明显大于常温下对比试件,刚度退化速度也更快。恒温60min、120min和180min的试件较常温对比试件的强度衰减率分别为16.1%、19.3%和24.8%;沿X轴加载,加载偏心距分别为40mm和80mm试件强度较轴心加载的试件分别降低了9%和14.1%;偏心受压试件在最终破坏时的极限变形量随偏心距的增大而明显增大,大体呈现线性趋势。腹杆间距对高温后轴压试件的前期刚度影响不大,加载中期腹杆间距为200mm的试件T-04轴压刚度要明显优于腹杆间距为300mm和400mm的试件,极限承载力随水平腹杆间距变化无明显变化规律;高温后试件含钢率增加15%,破坏时的残余承载力增加了24%;不同加载角对高温后试件竖向变形-荷载曲线的前期影响较小,但当各试件临近极限荷载时,加载角为45°的试件竖向变形量明显大于加载角为0°和90°的试件。
[Abstract]:Profiled steel concrete special-shaped column is a new type of structural form of steel frame embedded in reinforced concrete. It is widely used in high rise buildings because of its good flexibility in layout and superior to the bearing capacity and seismic performance of ordinary concrete columns. With high rise building, it occupies a more and more important position in the present generation. The structure safety of the building is widely concerned. The damage of fire to the building is particularly serious in all kinds of disasters. Because of the high steel ratio and large area of fire, the bearing capacity loss and risk degree of the steel column are higher than that of the ordinary concrete column at high temperature. The disaster relief and later repair work provide a certain theoretical basis. It is necessary to further study the mechanical properties of the special-shaped columns after fire. This paper mainly studies the mechanical properties of the steel concrete T shaped columns after high temperature. The main work and conclusions are as follows: 11 T shaped SRC columns are designed in this paper, and the constant temperature conditions are carried out by the self-made electric heating furnace. Under the fire test of four sides, the mechanical tests were carried out on the specimens under different design variables and loading conditions (horizontal bar spacing, steel ratio, loading angle, eccentricity). The related data were arranged and analyzed. The following conclusions were obtained: (1) after the high temperature action, the surface of the special shaped column changed to gray white with the color of the concrete surface in the high temperature area. In the middle section of the back of the column, there are fine cracks in the middle section of the back of the column, and the surface of the part of the specimen has a powder substance. The temperature of the test points near the surface of the T column is higher. The temperature field of the cross section is basically the same in the 3 hours at constant temperature. In theory, it is believed that the free expansion rate of the specimen is 0.47%, 0.67% and 0.75% respectively after the same high temperature of 1H, 2h and 3H at the same temperature at the same high temperature at.600 C. The axial deformation of each specimen increases linearly with the increase of the constant temperature. The axial deformation amount decreases with the increase of steel content. (2) the failure process and failure mode of the axial compression T column under the load are basically the same as those under the normal temperature. The failure mode of the eccentric compression member is similar to that of the axial compression specimen, but the initial and the exfoliation loads of the eccentric compression specimens are greatly advanced and the ultimate failure form is in the final form. On the eccentric compression side, the concrete is seriously flaking, the compression side steel is exposed and the other side appears the horizontal penetration crack. When the specimen is destroyed at the normal temperature, the column cracks are obviously less than those through the high temperature, and the specimen also maintains good integrity; the column has a large number of cracks when the specimen is destroyed by the excessive temperature. The fracture is wider, the main fracture is serious and the deformation is more serious. (3) the axial stiffness of the contrast specimen at normal temperature is obviously larger than that of the specimen under high temperature. The axial deformation of the specimen under the same load is obviously larger than the contrast specimen under the normal temperature, and the stiffness degradation speed is faster. The specimens at constant temperature 60min, 120min and 180min are better than the normal temperature. The strength attenuation rates of the specimens were 16.1%, 19.3% and 24.8%, respectively. The loading eccentricity of 40mm and 80mm specimens along the X axis decreased by 9% and 14.1% respectively. The ultimate deformation of the eccentric compression specimen increased with the increase of eccentricity, which generally showed a linear trend. At high temperature, the initial stiffness of the specimen has little effect on the initial stiffness. The T-04 axial compression stiffness of the specimen with 200mm at the middle stage of the loading is obviously better than that of the abdominal rod spacing of 300mm and 400mm, and the ultimate bearing capacity changes with the horizontal ventral rod spacing. The steel content of the specimen after the high temperature increases by 15%, and the residual bearing capacity increases by 24%. The effect of different loading angles on the vertical deformation load curve of the specimen after high temperature is less, but when the test parts are near the limit load, the vertical deformation of the specimen with the loading angle of 45 degrees is obviously larger than that of the loading angle of 0 and 90 degrees.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9
[Abstract]:Profiled steel concrete special-shaped column is a new type of structural form of steel frame embedded in reinforced concrete. It is widely used in high rise buildings because of its good flexibility in layout and superior to the bearing capacity and seismic performance of ordinary concrete columns. With high rise building, it occupies a more and more important position in the present generation. The structure safety of the building is widely concerned. The damage of fire to the building is particularly serious in all kinds of disasters. Because of the high steel ratio and large area of fire, the bearing capacity loss and risk degree of the steel column are higher than that of the ordinary concrete column at high temperature. The disaster relief and later repair work provide a certain theoretical basis. It is necessary to further study the mechanical properties of the special-shaped columns after fire. This paper mainly studies the mechanical properties of the steel concrete T shaped columns after high temperature. The main work and conclusions are as follows: 11 T shaped SRC columns are designed in this paper, and the constant temperature conditions are carried out by the self-made electric heating furnace. Under the fire test of four sides, the mechanical tests were carried out on the specimens under different design variables and loading conditions (horizontal bar spacing, steel ratio, loading angle, eccentricity). The related data were arranged and analyzed. The following conclusions were obtained: (1) after the high temperature action, the surface of the special shaped column changed to gray white with the color of the concrete surface in the high temperature area. In the middle section of the back of the column, there are fine cracks in the middle section of the back of the column, and the surface of the part of the specimen has a powder substance. The temperature of the test points near the surface of the T column is higher. The temperature field of the cross section is basically the same in the 3 hours at constant temperature. In theory, it is believed that the free expansion rate of the specimen is 0.47%, 0.67% and 0.75% respectively after the same high temperature of 1H, 2h and 3H at the same temperature at the same high temperature at.600 C. The axial deformation of each specimen increases linearly with the increase of the constant temperature. The axial deformation amount decreases with the increase of steel content. (2) the failure process and failure mode of the axial compression T column under the load are basically the same as those under the normal temperature. The failure mode of the eccentric compression member is similar to that of the axial compression specimen, but the initial and the exfoliation loads of the eccentric compression specimens are greatly advanced and the ultimate failure form is in the final form. On the eccentric compression side, the concrete is seriously flaking, the compression side steel is exposed and the other side appears the horizontal penetration crack. When the specimen is destroyed at the normal temperature, the column cracks are obviously less than those through the high temperature, and the specimen also maintains good integrity; the column has a large number of cracks when the specimen is destroyed by the excessive temperature. The fracture is wider, the main fracture is serious and the deformation is more serious. (3) the axial stiffness of the contrast specimen at normal temperature is obviously larger than that of the specimen under high temperature. The axial deformation of the specimen under the same load is obviously larger than the contrast specimen under the normal temperature, and the stiffness degradation speed is faster. The specimens at constant temperature 60min, 120min and 180min are better than the normal temperature. The strength attenuation rates of the specimens were 16.1%, 19.3% and 24.8%, respectively. The loading eccentricity of 40mm and 80mm specimens along the X axis decreased by 9% and 14.1% respectively. The ultimate deformation of the eccentric compression specimen increased with the increase of eccentricity, which generally showed a linear trend. At high temperature, the initial stiffness of the specimen has little effect on the initial stiffness. The T-04 axial compression stiffness of the specimen with 200mm at the middle stage of the loading is obviously better than that of the abdominal rod spacing of 300mm and 400mm, and the ultimate bearing capacity changes with the horizontal ventral rod spacing. The steel content of the specimen after the high temperature increases by 15%, and the residual bearing capacity increases by 24%. The effect of different loading angles on the vertical deformation load curve of the specimen after high temperature is less, but when the test parts are near the limit load, the vertical deformation of the specimen with the loading angle of 45 degrees is obviously larger than that of the loading angle of 0 and 90 degrees.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9
【相似文献】
相关期刊论文 前10条
1 曲恒绪;型钢混凝土结构计算方法的比较[J];安徽建筑;2003年06期
2 朱s，
本文编号：2136580
本文链接：https://www.wllwen.com/jianzhugongchenglunwen/2136580.html
