振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2015年
12期
58-64,100
,共8页
梁柱中节点%应变率%二项式逻辑回归模型%黏结滑移%承载力
樑柱中節點%應變率%二項式邏輯迴歸模型%黏結滑移%承載力
량주중절점%응변솔%이항식라집회귀모형%점결활이%승재력
interior beam-column joint%strain rate%binomial logistic regression model%bond slip%carrying capacity
受材料率敏感性的影响，钢筋混凝土构件具有率敏感效应，其受力性能在不同应变率水平下均有所不同。以往的研究多数集中于混凝土和钢筋材料率效应的研究，有关梁柱节点试件快速加载下的研究相对较少。研究了15个梁柱中节点在不同轴压比下的动态力学性能。运用二项式逻辑回归模型，预测了梁柱节点组合体的破坏形式，发现：随着应变率的提高，节点组合体内的裂缝数量不断减少，更倾向于单一主裂缝破坏；轴压比增大后，节点核心区的剪切变形以及斜裂缝与竖向轴力的夹角减小，应变率或轴压比增大后，节点组合体严重损伤部分发生转移；应变率的提高，对钢筋黏结强度起不利影响，钢筋滑移量随应变率的提高而增大。对比不同规范对节点抗剪承载力的计算公式发现，ASCE SEI 41－06规定的节点剪切强度因子偏高，ACI 352R －02规定的节点剪切强度因子较为合理，但 ASCE SEI 41－06和 ACI 352R－02都没有考虑轴压比对节点抗剪承载力的影响，相比之下 GB50010－2010考虑了轴压比的影响，计算结果更合理。在拟静态设计公式中采用材料动态强度的方法计算其承载力，往往会过高估计梁柱节点的抗剪承载力，是偏于不安全的。通过多元线性回归分析，得到了不同应变率及轴压比下节点水平抗剪承载力增大系数的经验方程。
受材料率敏感性的影響，鋼觔混凝土構件具有率敏感效應，其受力性能在不同應變率水平下均有所不同。以往的研究多數集中于混凝土和鋼觔材料率效應的研究，有關樑柱節點試件快速加載下的研究相對較少。研究瞭15箇樑柱中節點在不同軸壓比下的動態力學性能。運用二項式邏輯迴歸模型，預測瞭樑柱節點組閤體的破壞形式，髮現：隨著應變率的提高，節點組閤體內的裂縫數量不斷減少，更傾嚮于單一主裂縫破壞；軸壓比增大後，節點覈心區的剪切變形以及斜裂縫與豎嚮軸力的夾角減小，應變率或軸壓比增大後，節點組閤體嚴重損傷部分髮生轉移；應變率的提高，對鋼觔黏結彊度起不利影響，鋼觔滑移量隨應變率的提高而增大。對比不同規範對節點抗剪承載力的計算公式髮現，ASCE SEI 41－06規定的節點剪切彊度因子偏高，ACI 352R －02規定的節點剪切彊度因子較為閤理，但 ASCE SEI 41－06和 ACI 352R－02都沒有攷慮軸壓比對節點抗剪承載力的影響，相比之下 GB50010－2010攷慮瞭軸壓比的影響，計算結果更閤理。在擬靜態設計公式中採用材料動態彊度的方法計算其承載力，往往會過高估計樑柱節點的抗剪承載力，是偏于不安全的。通過多元線性迴歸分析，得到瞭不同應變率及軸壓比下節點水平抗剪承載力增大繫數的經驗方程。
수재료솔민감성적영향，강근혼응토구건구유솔민감효응，기수력성능재불동응변솔수평하균유소불동。이왕적연구다수집중우혼응토화강근재료솔효응적연구，유관량주절점시건쾌속가재하적연구상대교소。연구료15개량주중절점재불동축압비하적동태역학성능。운용이항식라집회귀모형，예측료량주절점조합체적파배형식，발현：수착응변솔적제고，절점조합체내적렬봉수량불단감소，경경향우단일주렬봉파배；축압비증대후，절점핵심구적전절변형이급사렬봉여수향축력적협각감소，응변솔혹축압비증대후，절점조합체엄중손상부분발생전이；응변솔적제고，대강근점결강도기불리영향，강근활이량수응변솔적제고이증대。대비불동규범대절점항전승재력적계산공식발현，ASCE SEI 41－06규정적절점전절강도인자편고，ACI 352R －02규정적절점전절강도인자교위합리，단 ASCE SEI 41－06화 ACI 352R－02도몰유고필축압비대절점항전승재력적영향，상비지하 GB50010－2010고필료축압비적영향，계산결과경합리。재의정태설계공식중채용재료동태강도적방법계산기승재력，왕왕회과고고계량주절점적항전승재력，시편우불안전적。통과다원선성회귀분석，득도료불동응변솔급축압비하절점수평항전승재력증대계수적경험방정。
Due to the rate sensitivity of materials,reinforced concrete members are sensitive to the strain rate,with varying mechanical properties at different strain rates.The majority of previous studies have focused more on the rate effect of concrete and reinforcement,but less on beam-column joints under high strain rate.The dynamic mechanical properties of 15 interior beam-column joint combination specimens subjected to various axial compression ratios were studied in the paper.The failure pattern of interior beam-column joint was predicted by binomial logistic regression model.The test results show that with the increasing of strain rate,the number of cracks in the joint declines continuously with a tendency to single main crack damage.The shear deformation in the core area of the joint and the angle between diagonal crack and vertical axial force decrease continuously as the axial compression ratio increases.Serious damage part of the joint transfers with the increasing of axial compression ratio or strain rate.The increasing of strain rate has adverse effect on the bond strength of reinforcement,and increases the bond slip of reinforcement.It can be found by the comparison of different specifications that the joint shear strength factor specified by ASCE SEI 41-06 is higher while that specified by ACI 352R-02 is more reasonable.However,both ASCE SEI 41-06 and ACI 352R-02 do not consider the effect of axial compression ratio on the joint shear carrying capacity.In contrast with the aforementioned building codes,GB50010-2010 considers the axial compression ratio effect with more reasonable calculation results.The study shows that if the values relating dynamic strength of concrete and reinforcement are directly substituted into the quasi-static design formulas to calculate the shear carrying capacity of the beam-column joint,it is unsafe due to the overestimate of the shear carrying capacity of the joint. An empirical equation to predict the dynamic increase factor of horizontal shear carrying capacity of beam-column joints under different axial compression ratios and strain rates was also proposed through multi-variate linear regression analysis.
