本文選題：鋼筋混凝土構件　切入點：鋼襯鋼筋混凝土壓力管道　出處：《武漢大學》2013年博士論文

【摘要】：混凝土結構的裂縫控制是關系到混凝土結構能否滿足耐久性與適用性要求的重要研究課題之一,但目前各國混凝土結構設計規(guī)范的裂縫控制標準和設計方法仍未及達成共識,裂縫控制標準與混凝土結構耐久性關系的研究還不夠完善。本文主要從荷載作用下的裂縫寬度計算值的保證率以及基于耐久性的裂縫控制標準的模糊可靠度分析入手,對普通鋼筋混凝土構件的裂縫控制標準以及鋼襯鋼筋混凝土壓力管道外包混凝土結構軸向裂縫的控制標準的安全度設置水平進行了較為深入的研究,相關研究成果可供國內(nèi)混凝土結構設計規(guī)范今后修訂時借鑒和參考。主要研究成果如下。 (1)提出了不同荷載組合下裂縫寬度計算值的等效保證率的概念。以頻遇組合或準永久組合下的裂縫寬度計算值與標準組合下調(diào)整短期裂縫寬度擴大系數(shù)后的裂縫寬度計算值相等效為原則,提出了不同荷載組合下裂縫寬度計算值的等效保證率的概念。利用等效保證率的概念,可以定量比較不同荷載組合下裂縫寬度計算值的安全度設置水平。針對當前正常使用極限狀態(tài)的可靠度研究尚不夠充分的條件下,本文所提出的不同荷載組合下裂縫寬度計算值的等效保證率指標作為一種合理的嘗試,避開了較為繁瑣的可靠指標計算,為裂縫控制的安全度設置水平提供了定量分析手段,為定量分析普通鋼筋混凝土構件裂縫控制標準的安全度設置水平開辟了一條新途徑。 (2)建立了計算單根構件裂縫寬度最大值的隨機模型。利用短期裂縫寬度計算值的保證率與短期裂縫寬度擴大系數(shù)的關系,將短期裂縫寬度擴大系數(shù)視為隨機變量,建立了計算單根構件裂縫寬度最大值的隨機模型。 (3)建立了裂縫引起構件耐久性損傷的綜合隸屬函數(shù)模型。基于裂縫對混凝土結構耐久性損傷影響的研究成果,以裂縫寬度最大值與保護層厚度之比以及裂縫寬度平均值與保護層厚度之比作為控制指標,建立了裂縫引起構件耐久性損傷的綜合隸屬函數(shù)模型。 (4)建立了裂縫控制標準與混凝土結構耐久性之間的定量關系。根據(jù)已建立的裂縫引起構件耐久性損傷的綜合隸屬函數(shù)模型,利用Monte-Carlo法對GB50010-2010規(guī)范鋼筋混凝土構件裂縫控制標準基于耐久性的可靠指標進行了計算分析,建立了裂縫控制標準與混凝土結構耐久性之間的定量關系。 (5)利用不同荷載組合下裂縫寬度計算值的等效保證率的概念和GB50010-2010規(guī)范鋼筋混凝土構件裂縫控制標準基于耐久性的可靠度分析結果,對我國現(xiàn)行規(guī)范的裂縫控制標準提出了以下修訂建議,可供我國現(xiàn)行規(guī)范今后修編時借鑒和參考： 1)宜采用荷載頻遇組合計算計算鋼筋混凝土構件的裂縫寬度,短期裂縫寬度計算值保證率仍宜保持為95%左右。 2)當保護層厚度c80mm時,裂縫寬度限值[Wmax]可取為保護層厚度c的線性函數(shù),即取[Wmax]=kc。對于潮濕大氣環(huán)境,可取k=0.005；對于氯離子侵蝕環(huán)境,可取k=-0.0035。當保護層厚度c80mm時,對于潮濕大氣環(huán)境[Wmax]可取為0.40mm；對于氯離子侵蝕環(huán)境[Wmax]可取為0.30mm。 (6)利用本文所提出的等效保證率概念,對我過現(xiàn)行電力行業(yè)標準DL/T5141-2001《水電站應力鋼管設計規(guī)范》鋼襯鋼筋混凝土壓力管道外包混凝土結構軸向裂縫寬度計算公式的安全度設置水平進行了分析比較,進而從保證裂縫寬度計算公式具有一定的計算精度和符合一定的安全度設置水平的要求出發(fā),對我國現(xiàn)行電力行業(yè)標準DL/T5141-2001關于鋼襯鋼筋混凝土壓力管道外包混凝土結構軸向裂縫的控制標準提出了以下修訂建議,可供我國現(xiàn)行電力行業(yè)標準DL/T5141-2001今后修編時借鑒和參考： 1)宜采用荷載標準組合計算鋼襯鋼筋混凝土壓力管道外包混凝土結構的軸向裂縫寬度,同時提出了兩套計算鋼襯鋼筋混凝土壓力管道外包混凝土結構軸向裂縫寬度的建議公式,相應的裂縫寬度計算值的保證率約在85%-90%之間。 2)關于最大裂縫寬度的限值,采用本文建議公式一時,最大裂縫寬度限值可取為0.3mm;采用本文建議公式二時,最大裂縫寬度限值可取為0.35mm。
[Abstract]:Concrete structure crack control is related to the concrete structure can meet one of the important research topics in durability and applicability, but the cracks in concrete structure design specification at present national standards and design methods and control has not yet reached a consensus on the crack control standard and concrete structure durability is not perfect. This paper mainly from the crack the width of loading of the calculated value of the guarantee rate and durability based on crack control standard of fuzzy reliability analysis of reinforced concrete crack control standard and control standard of axial concrete structure crack of reinforced concrete penstock outsourcing the safety level is studied. The research results can for the revision of the code for design of concrete structures and the reference. The main research results are as follows.
(1) the equivalent value calculation of crack width under different combined loads. The concept of guaranteed rate value is equivalent to the principle of calculation of crack width with frequent combination or quasi permanent combination of crack width calculation value and standard under the combination of short-term adjustment after the expansion of the crack width coefficient, the equivalent value calculation of crack width in different load under the combination of the concept of guaranteed rate. Using the equivalent guarantee rate concept, value calculation of crack width can be quantitatively compared under different load combinations the safety level. In view of the current research on reliability of serviceability limit state is still not sufficient conditions, the equivalent value calculation of crack width in different load combinations is proposed under the guarantee index as a reasonable attempt to avoid the tedious calculation of reliability index, provides a quantitative analysis method for the safety level of crack control, fixed A new way is opened up to analyze the level of safety of the crack control standard of ordinary reinforced concrete members.
(2) establish a stochastic model to calculate the maximum value of a single component. The crack width calculated with short-term crack width and crack width rate guarantee short-term expansion coefficient, short-term crack width expansion coefficient as random variables, stochastic model is established to calculate the maximum value of a single component crack width.
(3) establish a comprehensive membership function model of cracks caused by component durability damage. The effect of the crack on the durability of reinforced concrete structure based on the maximum crack width and the protective layer thickness ratio and average crack width and thickness of the protective layer is used as control index, established the cracks caused by the integrated component membership the function model of durability damage.
(4) to establish the quantitative relationship between the crack control standard and the durability of concrete structures. According to the established fracture caused by the integrated component membership function model of durability damage of reinforced concrete members, the GB50010-2010 specification standard of crack control durability based on reliability index were calculated and analyzed by using Monte-Carlo method, established a quantitative relationship between the crack the control standard and the durability of concrete structures.
(5) calculated using equivalent crack width under different load combinations to ensure the concept and specification of GB50010-2010 reinforced concrete structure crack control standard reliability analysis results based on durability rate of cracks in the current specification of the control standard and put forward the following suggestions, for our current standard in the future revision of reference:
1) the crack width of reinforced concrete members should be calculated by the combination of load frequency, and the guarantee rate of the short term crack width should remain about 95%.
2) when the protective layer thickness of c80mm, maximum crack width [Wmax] desirable as a linear function of the thickness of the protective layer of C, which is [Wmax]=kc. to the humid atmosphere, desirable for environmental k=0.005; chloride ion erosion, desirable k=-0.0035. when the protective layer thickness of c80mm, the wet atmospheric environment [Wmax] can be 0.40mm; for chloride ion erosion the environment [Wmax] can be 0.30mm.
(6) using the equivalent proposed the concept of guaranteed rate, safety level of the current power industry standard of DL/T5141-2001< hydropower station should be axial concrete structure crack of reinforced concrete penstock width specification design capacity of steel pipe outsourcing formula is analyzed and compared, and then from that crack width calculation formula has a certain accuracy and meet certain safety level requirements, the power industry standard in China DL/T5141-2001 on the axial wall of steel lined reinforced concrete penstocks concrete structure cracking control standard put forward the following suggestions, for our standard DL/T5141-2001 current power industry in the future revision of reference:
1) should adopt the combination of standard axial load calculation of crack width of reinforced concrete penstock concrete structure at the same time, two sets of calculation of steel lined reinforced concrete penstocks axial crack width formula is proposed, calculation of crack width of the corresponding guarantee rate is about 85%-90%.
2) about the limit of the maximum crack width, the maximum crack width limit can be 0.3mm when using the recommended formula in this paper. When the formula two is recommended in this paper, the maximum crack width limit can be 0.35mm..

【學位授予單位】：武漢大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU375

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