型钢混凝土T形柱耐火性能的试验研究
发布时间：2018-08-16 19:38
【摘要】：型钢混凝土异形柱就是在混凝土异形柱中配置纵向型钢及相应腹筋的结构构件,作为一种新型结构,它具有承载能力高,结构布置灵活、抗震性能好等优点,被广泛推广应用,但因为其含钢量高,受火面大的特点,决定了其在火灾中更容易发生破坏,而目前国内外对型钢混凝土异形柱在火灾中的试验研究较少,尤其是应用较为广泛的T型截面。本文设计并浇筑了9根型钢混凝土T形柱,进行了高温下的耐火试验研究,分析轴压比、偏心距、加载角、腹筋间距及含钢率对型钢混凝土T形柱破坏现象、温度场特征及耐火极限的影响,得出如下结论:(1)异形柱在受高温区域呈现乳白色,且耐高温时间的越长,现象越明显。在轴心受压时异形部位破坏程度较其他位置严重,且裂缝均为竖向裂缝或少量的左右对称的斜向裂缝,偏心受压时裂缝以向偏心方向倾斜的斜向裂缝居多,偏心距较大时,在偏心加载点相对的一侧会受拉出现水平裂缝。(2)截面各位置升温趋势大体相同,前30min升温较慢,之后进入短时间的温度平台,持续时间约为10~20min,平台区温度各测点有所不同,但均在100~150℃区间内,且越靠近中心区域平台现象越明显,平台过后温度呈抛物线式上升。试件内部温度场的分布基本符合离炉壁越远温度越低的规律,但又随参数的变化有多不同。轴心受压时,随着轴压比的增大,T形柱内部升温速率越快。偏心受压时,沿偏心方向的温度升温速率较快。异形柱异形区域升温速率普遍偏大。(3)在恒载升温过程中,型钢混凝土T形柱的轴向位移变化趋势大体相同:前40min左右变化不明显,之后轴向位移缓慢上升达到最高点后呈近似线性下降,位移上升的幅度及时间随着轴压比和偏心距的增大而逐渐减小,甚至在一定轴压比和偏心距下,轴向位移不出现上升现象而直接下降。(4)随着轴压比、偏心距的增大,耐火极限逐渐减小,当轴压比增大0.2时,耐火极限降低30%左右,而当偏心距增大20mm时,耐火极限降低10%左右;偏心受压时,加载点在强轴上时,耐火极限较大,在45°方向及弱轴方向耐火极限较小,且仅为前者的65%;腹筋间距对耐火极限的影响较小,在符合构造要求的前提下,腹筋间距增大,耐火极限略有降低;随着含钢率的增大,耐火极限显著提高,在含钢率提高15%时,耐火极限提高了将近一倍。(5)综合所有因素对型钢混凝土T型柱耐火极限的影响,含钢率的影响最大,轴压比、偏心距和加载角的影响次之,腹筋间距的影响最小。
[Abstract]:Steel reinforced concrete special-shaped columns are structural members with longitudinal sections and corresponding webs in concrete special-shaped columns. As a new type of structure, it has the advantages of high bearing capacity, flexible structure arrangement, good seismic performance, and has been widely used. However, due to its high steel content and large fire surface, it is more likely to be destroyed in fire. However, there are few experimental studies on special-shaped steel reinforced concrete columns in fire at home and abroad, especially for T-shaped sections, which are widely used in fire. In this paper, 9 T-shaped columns of SRC are designed and cast, and the fire resistance is studied under high temperature. The failure phenomenon of SRC T-shaped columns caused by axial compression ratio, eccentricity, loading angle, spacing of web bars and steel content is analyzed. The characteristics of temperature field and the effect of fire resistance limit are concluded as follows: (1) the abnormal column appears milky white in the region of high temperature, and the longer the time of high temperature resistance, the more obvious the phenomenon is. Under axial compression, the damage degree of the special-shaped part is more serious than that of other places, and the cracks are all vertical cracks or a few symmetrical oblique fractures. When eccentric compression, the fractures are inclined to the eccentric direction, and when the eccentricity is large, the fracture is inclined to the eccentric direction, and when the eccentricity is large, the fracture is inclined to the eccentric direction. Horizontal cracks will appear on the opposite side of eccentric loading point. (2) the temperature rise trend of each section is about the same, the temperature rise before 30min is slow, and then enter the temperature platform for a short time, the duration is about 10 ~ 20 min, and the temperature measuring points in the platform area are different. However, in the range of 100 鈩，
本文编号：2186978
[Abstract]:Steel reinforced concrete special-shaped columns are structural members with longitudinal sections and corresponding webs in concrete special-shaped columns. As a new type of structure, it has the advantages of high bearing capacity, flexible structure arrangement, good seismic performance, and has been widely used. However, due to its high steel content and large fire surface, it is more likely to be destroyed in fire. However, there are few experimental studies on special-shaped steel reinforced concrete columns in fire at home and abroad, especially for T-shaped sections, which are widely used in fire. In this paper, 9 T-shaped columns of SRC are designed and cast, and the fire resistance is studied under high temperature. The failure phenomenon of SRC T-shaped columns caused by axial compression ratio, eccentricity, loading angle, spacing of web bars and steel content is analyzed. The characteristics of temperature field and the effect of fire resistance limit are concluded as follows: (1) the abnormal column appears milky white in the region of high temperature, and the longer the time of high temperature resistance, the more obvious the phenomenon is. Under axial compression, the damage degree of the special-shaped part is more serious than that of other places, and the cracks are all vertical cracks or a few symmetrical oblique fractures. When eccentric compression, the fractures are inclined to the eccentric direction, and when the eccentricity is large, the fracture is inclined to the eccentric direction, and when the eccentricity is large, the fracture is inclined to the eccentric direction. Horizontal cracks will appear on the opposite side of eccentric loading point. (2) the temperature rise trend of each section is about the same, the temperature rise before 30min is slow, and then enter the temperature platform for a short time, the duration is about 10 ~ 20 min, and the temperature measuring points in the platform area are different. However, in the range of 100 鈩，
本文编号：2186978
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