建筑结构学报2026，Vol.47Issue(8)：149-159,11.DOI:10.14006/j.jzjgxb.2025.0346
基于等值应力法的配筋UHPC梁开裂荷载计算方法
Calculation method for cracking load of reinforced UHPC beams based on stress equivalence method
摘要
Abstract
To establish a calculation method for the cracking load of reinforced ultra-high performance concrete(UHPC)beams,experimental studies on the cracking performance of 20 reinforced UHPC beams were conducted with variables including steel fiber content,reinforcement ratio,shear span-to-depth ratio,and stirrup ratio.Based on principal stress contour analysis,a boundary baseline was defined to accurately determine the principal stress in the tension zone of UHPC beams,thereby identifying the most vulnerable cracking zone and the initial crack type.For the most vulnerable cracking zone,an influence coefficient for the diagonal section modulus was introduced to establish a calculation formula for the cracking shear force.Considering the tensile plasticity of UHPC,a simplified formula for the cracking moment was derived using internal force equilibrium and deformation compatibility conditions.By comparing the magnitudes of the two types of cracking loads,the initial crack type and its occurrence region were further clarified from the load perspective.Results show that within the test range,when the shear span-to-depth ratio exceeds 3.18,the failure mode is flexural failure;when it is less than 3.18,shear failure dominates.The cracking performance and load-bearing capacity of flexural beams are positively correlated with both steel fiber content and reinforcement ratio.When the distance from the bottom of longitudinal reinforcement to the tension zone concrete edge exceeds 26 mm,the enhancement in cracking performance and load-bearing capacity tends to plateau.For shear beams,the cracking performance and load-bearing capacity are negatively correlated with the shear span-to-depth ratio,while the stirrup ratio has a minor effect on cracking performance.The most vulnerable cracking zone is located within the range of 81％to 100％of the shear-bending segment length from the bottom of the test beam to the support,where diagonal cracks first appear.The proposed cracking shear force formula accurately reflects the location of the initial diagonal crack,with a mean ratio of calculated values to experimental results from relevant literature of 0.98 and a coefficient of variation of 0.09.The cracking moment formula comprehensively accounts for the effects of reinforcement ratio and steel fiber content,with a mean ratio of calculated values to experimental results from relevant literature of 1.02 and a coefficient of variation of 0.08.关键词
超高性能混凝土/最易开裂区/开裂剪力/开裂弯矩/计算方法Key words
ultra-high performance concrete/most vulnerable cracking zone/cracking shear force/cracking moment/calculation method分类
建筑与水利引用本文复制引用
孙永新,蔺鹏臻,王亚朋..基于等值应力法的配筋UHPC梁开裂荷载计算方法[J].建筑结构学报,2026,47(8):149-159,11.基金项目
甘肃省科技重大专项(25ZDGA009),甘肃省自然科学基金项目(25JRRA165). （25ZDGA009）
