【摘要】：隨著大型商業(yè)綜合體、航站樓等超長(zhǎng)混凝土結(jié)構(gòu)在我國(guó)大量興建，連續(xù)不設(shè)縫結(jié)構(gòu)的工程應(yīng)用日漸增多。在混凝土收縮及溫度作用下，超長(zhǎng)混凝土框架結(jié)構(gòu)的梁板中因受到約束而產(chǎn)生較大的拉應(yīng)力，造成結(jié)構(gòu)的開(kāi)裂。因此，超長(zhǎng)混凝土框架結(jié)構(gòu)必須通過(guò)有效的設(shè)計(jì)和合理的施工對(duì)裂縫進(jìn)行控制。 本文運(yùn)用SAP2000有限元軟件，首先對(duì)300米~500米超長(zhǎng)混凝土框架結(jié)構(gòu)的溫度收縮效應(yīng)進(jìn)行了系列模擬分析，總結(jié)了其內(nèi)力及應(yīng)力分布規(guī)律。 然后，分析了補(bǔ)償收縮混凝土、預(yù)應(yīng)力技術(shù)、后澆帶布置以及其它施工構(gòu)造等裂縫控制措施。①在補(bǔ)償收縮混凝土方面：分析膨脹混凝土的補(bǔ)償收縮效果，并總結(jié)了其在超長(zhǎng)混凝土結(jié)構(gòu)中的應(yīng)用原則；②在預(yù)應(yīng)力技術(shù)方面：總結(jié)了預(yù)應(yīng)力技術(shù)在超長(zhǎng)結(jié)構(gòu)中的設(shè)計(jì)原則，分析了次軸力對(duì)預(yù)應(yīng)力效應(yīng)的影響，提出了次軸力系數(shù)在框架結(jié)構(gòu)中的取值范圍；③在后澆帶布置方面：通過(guò)結(jié)合預(yù)應(yīng)力筋張拉對(duì)后澆帶提出了新的劃分方案，并運(yùn)用算例分析，評(píng)價(jià)了后澆帶布置的新方案；④在其它施工構(gòu)造措施方面：結(jié)合算例，分析了結(jié)構(gòu)端部若干排設(shè)定向滑動(dòng)支座方案的有效性。 最后，提出了500米內(nèi)超長(zhǎng)混凝土框架結(jié)構(gòu)的設(shè)計(jì)方案及設(shè)計(jì)步驟，并通過(guò)具體結(jié)構(gòu)算例對(duì)所提出的設(shè)計(jì)方案進(jìn)行了驗(yàn)證。 依據(jù)以上計(jì)算及分析內(nèi)容得到結(jié)論如下： ①在均勻降溫作用下，框架結(jié)構(gòu)隨其縱向長(zhǎng)度的增長(zhǎng)，溫度內(nèi)力的分布規(guī)律是一致的，其具體分布規(guī)律如下：由端部到中部節(jié)點(diǎn)變形、梁柱截面的峰值內(nèi)力及應(yīng)力逐漸減小，梁板中的平均內(nèi)力及應(yīng)力逐漸增大；框架柱的最大拉應(yīng)力出現(xiàn)在邊柱底端截面，框架梁的最大拉應(yīng)力出現(xiàn)在邊梁靠近邊柱的端截面，樓板的最大拉應(yīng)力出現(xiàn)在結(jié)構(gòu)對(duì)稱(chēng)軸處截面。在多層框架結(jié)構(gòu)中，各層溫度作用的分布規(guī)律與單層的相似；隨著樓層的增加，溫度收縮效應(yīng)迅速衰減，，只在底部?jī)蓪虞^為顯著，以至于其余樓層可以忽略不計(jì)。 ②對(duì)預(yù)應(yīng)力的配筋設(shè)計(jì)除考慮預(yù)應(yīng)力損失外，還應(yīng)計(jì)及次軸力的不利影響。通過(guò)結(jié)合后澆帶的劃分方案張拉預(yù)應(yīng)力筋可以部分的提高預(yù)壓力效應(yīng)，減弱結(jié)構(gòu)中的次軸力。由此得到考慮了預(yù)應(yīng)力筋張拉的后澆帶設(shè)置原則為：后澆帶所劃分的預(yù)應(yīng)力筋張拉單元的跨數(shù)宜少；后澆帶澆筑完成后，預(yù)應(yīng)力筋張拉單元的跨數(shù)應(yīng)少（建議不超過(guò)兩跨），且在結(jié)構(gòu)中部應(yīng)布置跨數(shù)少的預(yù)應(yīng)力筋張拉單元。 ③結(jié)構(gòu)端部若干排設(shè)定向滑動(dòng)支座可以有效減弱超長(zhǎng)混凝土框架結(jié)構(gòu)的溫度收縮作用。在結(jié)構(gòu)端部的減弱作用最顯著，越向結(jié)構(gòu)中部減弱作用逐漸下降。 ④對(duì)于500以?xún)?nèi)的超長(zhǎng)混凝土結(jié)構(gòu)，按照本文提出的裂縫控制設(shè)計(jì)方法，采用高性能補(bǔ)償收縮混凝土、結(jié)合預(yù)應(yīng)力筋張拉的后澆帶合理布置方案以及在結(jié)構(gòu)端部設(shè)定向滑動(dòng)支座等措施，可以滿(mǎn)足我國(guó)現(xiàn)行規(guī)范對(duì)裂縫控制的要求。
[Abstract]:With the large-scale commercial complex and the large-scale construction of super-long concrete structures such as terminal buildings in China, the application of continuous jointless structures is increasing day by day. The structure must be controlled by effective design and reasonable construction.
In this paper, the temperature shrinkage effect of 300-500 m super-long concrete frame structure is simulated and analyzed by using SAP2000 finite element software, and the internal stress and stress distribution are summarized.
Then, the crack control measures such as shrinkage compensating concrete, prestressing technology, post-pouring zone layout and other construction structures are analyzed. The design principle of force technology in super-long structure is analyzed, the influence of secondary axial force on prestressing effect is analyzed, and the value range of secondary axial force coefficient in frame structure is proposed. 3. In the layout of post-pouring belt, a new division scheme of post-pouring belt is proposed by combining the tension of prestressing tendon, and the layout of post-pouring belt is evaluated by an example analysis. In other construction measures, the effectiveness of several rows of sliding bearings at the end of the structure is analyzed by an example.
Finally, the design scheme and design steps of the super-long concrete frame structure within 500 meters are proposed, and the proposed design scheme is verified by a concrete structural example.
Based on the above calculation and analysis, the conclusions are as follows:
(1) Under the uniform cooling effect, the temperature internal force distribution law of the frame structure is consistent with the increase of its longitudinal length. The concrete distribution law is as follows: from the end to the middle node deformation, the peak internal force and stress of the beam-column section gradually reduce, the average internal force and stress in the beam-slab gradually increase; the maximum tensile stress of the Frame-Column appears. In the bottom section of the side column, the maximum tensile stress of the frame beam appears at the end section near the side column, and the maximum tensile stress of the floor appears at the symmetrical axial section. It is so obvious that the remaining floors can be neglected.
In addition to prestressing loss, the negative influence of secondary axial force should be taken into account in the design of prestressing reinforcement. The prestressing effect can be partially increased and the secondary axial force can be weakened by tensioning the prestressing reinforcement in combination with the dividing scheme of post-cast strips. The span of the prestressed tendon tension element should be less than two spans, and the span of the prestressed tendon tension element should be less than two spans, and the prestressed tendon tension element with fewer spans should be arranged in the middle of the structure.
(3) Several rows of sliding bearings at the end of the structure can effectively reduce the temperature shrinkage of the super-long concrete frame structure.
(4) For the super-long concrete structure within 500 years, according to the crack control design method proposed in this paper, adopting high performance shrinkage compensating concrete, combining with the reasonable layout of post-cast-in-place belt stretched by prestressed tendons and setting sliding bearings at the end of the structure, can meet the requirements of the current code for crack control in China.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TU375.4

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