带约束构造剪力键钢–混凝土组合箱梁数值分析

Numerical Analysis of Steel-Concrete Composite Beams Connected by Shear Connectors with Constrained Measures

摘要: 针对钢–混凝土组合梁的纵向局压劈裂与负弯矩区混凝土板易受拉开裂，提出将带约束构造剪力键与负弯矩区附加钢板应用在组合梁中。通过数值模拟研究了采用上述两种构造的40 m钢–混凝土组合箱梁的受力性能，分析探讨了不同挠跨比下组合箱梁的承载力、刚度及应力状态。研究结果表明：(1) 有限元模型结果与理论计算值吻合较好，可实现组合梁中组合力学性能的量化，为组合梁优化及精细化设计提供了通用简化方法；(2) 连续组合梁采用附加钢板形成双重组合后，可将变截面梁简化等效为等截面组合梁，简化组合梁的设计与应用，能高效提高组合梁的刚度、材料利用效率，降低建造成本，但中支座剪跨段栓钉连接件剪力是边支座剪跨段的4.3~4.5倍，应加强剪力连接件疲劳强度及结合面混凝土耐久性验算；(3) 算例中简支组合梁可取挠跨比1/500作为正常使用极限状态的挠度控制指标，连续组合梁取不大于挠跨比1/600作为正常使用极限状态的挠度控制指标；(4) 组合梁的优化及设计应建立简化实用的精细化分析模型，对组合梁中组合力学性能和耐久性进行量化；通过数值分析，可逐步建立组合梁中混凝土、钢以及结合面的各个部位在不同工作状态下的数值技术标准，为组合梁的进一步发展应用提供参考。

Abstract: In view of the longitudinal penetrating cracks and negative moment zone which is easy to crack in concrete slab of steel-concrete composite beams, it is proposed in this paper to apply the shear connectors with constrained measure and additional steel plate in the negative moment zone to the beam members. The mechanical performance of 40 m steel-concrete composite box girder with the above two structures is studied by numerical simulation, and the stiffness, stability and stress state of the composite box girder with different deflection span ratios are analyzed and discussed. The results show that: (1) the results of the finite element model in this paper are in good agreement with the theoretical calculated values, which can realize the quantification of the combined mechanical properties of composite beams, and provide a general simplified method for the optimization and fine design of composite beams; (2) after the continuous composite beam is formed with additional steel plates, the variable section beam can be simplified to equal section composite beam, simplifying the design and application of composite beam, the stiffness and material utilization efficiency of the composite beam can be effectively improved under the premise of durability, and the construction cost can be reduced. However, the shear force of stud connectors in mid-support is 4.3 to 4.5 times that of the edge support, the fatigue strength and durability of the stud connectors and the concrete at the bonding surface should be checked and calculated; (3) in the example, the deflection span ratio of 1/500 of simply-supported composite beam can be used as the deflection control index of the normal use limit state of the simply-supported composite beam, and the continuous composite beam is taken as no more than 1/600 of the deflection span ratio as the deflection control index of the normal use limit state; (4) for the optimization and design of composite beams, a simplified and practical fine analysis model should be established to quantify the combined mechanical properties and durability of composite beams. Through numerical analysis, the numerical technical standards of concrete, steel and various parts of the joint surface in the composite beam can be gradually established under different working conditions, and the further development and application of the composite beam can be guided and promoted.