發(fā)布時間：2018-03-23 09:10

  本文選題：L形異形柱　切入點：火災(zāi)后　出處：《青島理工大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：型鋼混凝土異形柱除配置有型鋼外，還含有適量箍筋，其承載力和抗震性能得到明顯提高，軸壓比限值也可適當(dāng)放寬。當(dāng)前國內(nèi)外對型鋼混凝土異形柱的研究主要集中于常溫情況下，，而對抗火性能的研究幾乎處于空白階段，且尚未形成一套系統(tǒng)的計算理論和設(shè)計方法。通過對L形型鋼混凝土異形柱火災(zāi)后力學(xué)性能的研究，不僅為其火災(zāi)后損傷評估及修復(fù)加固工作提供依據(jù)，也可更好的完善我國抗火設(shè)計理論及相應(yīng)規(guī)程。全文從試驗研究、數(shù)值模擬、截面特性三個方面進(jìn)行系統(tǒng)研究，其主要工作和結(jié)論包括以下四個方面： 1．對8根L形型鋼混凝土異形柱進(jìn)行ISO834標(biāo)準(zhǔn)升溫曲線下兩面受火試驗，測得截面溫度場分布、軸向和側(cè)向位移、考察試件火災(zāi)后表面裂縫分布規(guī)律。結(jié)果表明：(1)爐溫曲線與ISO834標(biāo)準(zhǔn)升溫曲線基本吻合；(2)測點溫度隨著距受火面距離減小而逐漸增高，最高溫度達(dá)到500℃，15min~20min時間段內(nèi)曲線較為平緩，爾后升溫逐漸加快；(3)軸向位移最大值約6mm，最小值僅為1.1mm。 2．進(jìn)行常溫下靜力加載試驗，測得其火災(zāi)后極限承載力、混凝土和型鋼各自應(yīng)變、軸向和側(cè)向位移，以及柱中截面處混凝土與型鋼之間的粘結(jié)滑移，并觀察破壞現(xiàn)象。結(jié)果表明：(1)異形柱受壓過程可分為彈性、帶裂縫工作和破壞三個階段；(2)當(dāng)偏心距為60mm、100mm、180mm、240mm時，沿45°加載試件相對于0°加載，極限承載力分別降低了20.3％、20.8％、35.2％和38.1％；(3)忽略加載初期及末期產(chǎn)生的軸向位移值，基本維持在（10±2）mm范圍內(nèi)，混凝土和型鋼之間粘結(jié)滑移小于2mm。 3．采用有限元軟件ABAQUS進(jìn)行溫度場分析及損傷后結(jié)構(gòu)分析，得到截面溫度場分布、極限承載力、變形及應(yīng)變計算結(jié)果。結(jié)果表明：(1)截面溫度場變化規(guī)律與試驗結(jié)果基本一致；(2)柱1~柱9極限承載力計算結(jié)果與試驗結(jié)果誤差分別為7.7％、0.57％、11.2％、15.17％、15.08％、7.3％、9.9％、8.06％和13.5％；(3)軸向位移與側(cè)向位移曲線變化規(guī)律基本相似，沿0°加載時， Y軸方向最大側(cè)移約為X軸方向的1/2。 4．通過試驗與計算結(jié)果，分析廣義中性軸位置、截面平均應(yīng)變、Nu-e曲線及Nu-Mu相關(guān)曲線，進(jìn)一步揭示其火災(zāi)后的力學(xué)性能，此外，通過數(shù)值計算評估其在不同受火時間后的截面損傷。結(jié)果表明：(1)從平均應(yīng)變意義上講，平截面假定對火災(zāi)后L形型鋼混凝土異形柱仍然適用；(2)由Nu-Mu相關(guān)曲線可以看出，0°加載時得到的相關(guān)曲線與坐標(biāo)軸之間的包絡(luò)面積與45°加載相比較大；(3)嚴(yán)重?fù)p傷區(qū)域邊界在截面內(nèi)類似于“圓弧形”，試件受火1h、1.5h、2h、3h后損傷深度分別為30mm、36mm、46mm和65mm，占整個截面面積的17.68％、20.05％、25.75％和36.91％。
[Abstract]:In addition to the profile steel, the special-shaped steel reinforced concrete column also contains a suitable amount of stirrups, and its bearing capacity and seismic performance are obviously improved. The limit of axial compression ratio can also be relaxed. At present, the research on SRC special-shaped columns at home and abroad is mainly focused on the normal temperature, but the research on fire resistance is almost blank. And a set of systematic calculation theory and design method have not been formed. Through the study of mechanical properties of L-shaped steel reinforced concrete special-shaped columns after fire, it not only provides the basis for damage assessment and repair and reinforcement work after fire. It can also better improve the fire design theory and the corresponding rules. This paper studies systematically from three aspects: experimental research, numerical simulation and cross-section characteristics. The main work and conclusions include the following four aspects:. 1. Eight L-shaped steel reinforced concrete special-shaped columns were subjected to fire test under ISO834 standard heating curve. The temperature field distribution, axial displacement and lateral displacement of the section were measured. The distribution of surface cracks in specimens after fire is investigated. The results show that the temperature curve of the furnace agrees with the ISO834 standard temperature curve basically. (2) the temperature of the measuring point increases with the decrease of the distance from the fire surface. The maximum temperature of 500 鈩

本文編號：1652811