【摘要】：型鋼混凝土異形柱就是在混凝土異形柱中配置縱向型鋼及相應(yīng)腹筋的結(jié)構(gòu)構(gòu)件,作為一種新型結(jié)構(gòu),它具有承載能力高,結(jié)構(gòu)布置靈活、抗震性能好等優(yōu)點(diǎn),被廣泛推廣應(yīng)用,但因?yàn)槠浜摿扛?受火面大的特點(diǎn),決定了其在火災(zāi)中更容易發(fā)生破壞,而目前國內(nèi)外對型鋼混凝土異形柱在火災(zāi)中的試驗(yàn)研究較少,尤其是應(yīng)用較為廣泛的T型截面。本文設(shè)計(jì)并澆筑了9根型鋼混凝土T形柱,進(jìn)行了高溫下的耐火試驗(yàn)研究,分析軸壓比、偏心距、加載角、腹筋間距及含鋼率對型鋼混凝土T形柱破壞現(xiàn)象、溫度場特征及耐火極限的影響,得出如下結(jié)論:(1)異形柱在受高溫區(qū)域呈現(xiàn)乳白色,且耐高溫時間的越長,現(xiàn)象越明顯。在軸心受壓時異形部位破壞程度較其他位置嚴(yán)重,且裂縫均為豎向裂縫或少量的左右對稱的斜向裂縫,偏心受壓時裂縫以向偏心方向傾斜的斜向裂縫居多,偏心距較大時,在偏心加載點(diǎn)相對的一側(cè)會受拉出現(xiàn)水平裂縫。(2)截面各位置升溫趨勢大體相同,前30min升溫較慢,之后進(jìn)入短時間的溫度平臺,持續(xù)時間約為10~20min,平臺區(qū)溫度各測點(diǎn)有所不同,但均在100~150℃區(qū)間內(nèi),且越靠近中心區(qū)域平臺現(xiàn)象越明顯,平臺過后溫度呈拋物線式上升。試件內(nèi)部溫度場的分布基本符合離爐壁越遠(yuǎn)溫度越低的規(guī)律,但又隨參數(shù)的變化有多不同。軸心受壓時,隨著軸壓比的增大,T形柱內(nèi)部升溫速率越快。偏心受壓時,沿偏心方向的溫度升溫速率較快。異形柱異形區(qū)域升溫速率普遍偏大。(3)在恒載升溫過程中,型鋼混凝土T形柱的軸向位移變化趨勢大體相同:前40min左右變化不明顯,之后軸向位移緩慢上升達(dá)到最高點(diǎn)后呈近似線性下降,位移上升的幅度及時間隨著軸壓比和偏心距的增大而逐漸減小,甚至在一定軸壓比和偏心距下,軸向位移不出現(xiàn)上升現(xiàn)象而直接下降。(4)隨著軸壓比、偏心距的增大,耐火極限逐漸減小,當(dāng)軸壓比增大0.2時,耐火極限降低30%左右,而當(dāng)偏心距增大20mm時,耐火極限降低10%左右;偏心受壓時,加載點(diǎn)在強(qiáng)軸上時,耐火極限較大,在45°方向及弱軸方向耐火極限較小,且僅為前者的65%;腹筋間距對耐火極限的影響較小,在符合構(gòu)造要求的前提下,腹筋間距增大,耐火極限略有降低;隨著含鋼率的增大,耐火極限顯著提高,在含鋼率提高15%時,耐火極限提高了將近一倍。(5)綜合所有因素對型鋼混凝土T型柱耐火極限的影響,含鋼率的影響最大,軸壓比、偏心距和加載角的影響次之,腹筋間距的影響最小。
[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，

本文編號：2186978