硅酸盐学报

基于薄膜效应的混杂纤维轻骨料混凝土梁极限承载力试验

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潘建军 ¹ , 陈万祥 ¹^,²^,³ , 周新军 ¹ , 彭晓丽 ¹

硅酸盐学报 | 水泥基材料增强增韧及其复合材料专题—研究论文 2026,54(5): 1727-1739

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硅酸盐学报 |水泥基材料增强增韧及其复合材料专题—研究论文 2026 , 54 (5) : 1727 -1739

基于薄膜效应的混杂纤维轻骨料混凝土梁极限承载力试验

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潘建军¹, 陈万祥¹^,²^,³, 周新军¹, 彭晓丽¹

作者信息

^1．陆军工程大学爆炸冲击防灾减灾全国重点实验室，南京 210007

^2．中山大学土木工程学院，广东珠海 519082

^3．隧道工程灾变防控与智能建养全国重点实验室，广州 510275

通讯作者:

陈万祥（1977—），男，博士，副教授。

作者简介:

潘建军（1994—），男，博士研究生。

Ultimate Bearing Capacities of Hybrid Fiber Reinforced Lightweight Aggregate Concrete Beam with Membrane Effect

Jianjun PAN¹, Wanxiang CHEN¹^,²^,³, Xinjun ZHOU¹, Xiaoli PENG¹

Affiliations

^1.State Key Laboratory of Disaster Prevention & Mitigation of Explosion & Impact, Army Engineering University of PLA, Nanjing 210007, China

^2.School of Civil Engineering, Sun Yat-sen University, Zhuhai 519082, Guangdong, China

^3.State Key Laboratory for Tunnel Engineering, Guangzhou 510275, China

Corresponding Author:

CHEN Wanxiang (1977-), male, Ph.D., Associate Professor. E-mail: cwx_0806@sohu.com

PAN Jianjun (1994-), male, Doctoral candidate. E-mail: pjj425750443@163.com

出版时间: 2025-09-26 doi: 10.14062/j.issn.0454-5648.20250410

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摘要

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薄膜效应对极限承载力的增强机制已形成共识，但尚缺乏定量分析的方法。为模拟实际工程中梁式结构的薄膜效应，设计制作了一套考虑水平刚度与转动刚度的支座约束装置。采用四点弯曲加载方式对10根混杂纤维轻骨料混凝土（HFR-LWC）梁进行了静力加载试验，分析了约束条件、配筋率及有无纤维对HFR-LWC梁极限承载力的贡献，得到了HFR-LWC梁跨中应变、裂缝分布及极限承载力变化规律，量化分析了水平刚度和转动刚度对薄膜效应的影响，结果表明：极限抗力对支座转动刚度的变化更为敏感；考虑薄膜作用的HFR-LWC梁极限承载力较普通支座LWC梁提高1.5~5.5倍，特殊端部约束下梁的中和轴下移且加载时上升缓慢，混凝土受压区高度增加；混杂纤维提高了梁的韧性，裂缝开展细且密，有利于薄膜效应的发挥。

关键词

薄膜效应 / 轻骨料混凝土 / 混杂纤维 / 静力加载试验 / 极限承载力

Abstract

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Introduction

Lightweight aggregate concrete (LWC) offers some advantages like low density, thermal insulation, heat resistance, fire resistance, and excellent seismic performance. The incorporation of hybrid fibers further enhances its toughness, durability, and crack resistance, resulting in a composite material known as hybrid fiber reinforced-lightweight aggregate concrete (HFR-LWC). In protective engineering, deformations induce a "membrane effect" at the end restraints of structures, altering their ultimate resistance and failure modes. Conventional load-bearing components are often simplified as simply supported or fixed in mechanical analyses, neglecting the influence of the membrane effect. This leads to conservative designs for ultimate bearing capacity, preventing the full utilization of component strength. Therefore, investigating the membrane effect's contribution to improving component bearing capacity is of significant importance. This paper was to design and fabricate a set of support restraint devices for horizontal stiffness and rotational stiffness to simulate the membrane effect in beam structures. Four-point bending tests were conducted on ten HFR-LWC beams under static loading. The contributions of restraint conditions, reinforcement ratios, and the presence of fibers to the ultimate bearing capacity of HFR-LWC beams were analyzed. The variation patterns of mid-span strain, crack distribution, and ultimate bearing capacity of the HFR-LWC beams were examined. In addition, the influences of horizontal stiffness and rotational stiffness on the membrane effect were also quantitatively analyzed.

Methods

Based on the Technical Specification for Lightweight Aggregate Concrete (JGJ/T 12—2019), this study developed a hybrid fiber reinforced lightweight aggregate concrete (HFR-LWC) with high strength, low density, and good workability through multiple mix proportion trials. Ten concrete beams with the dimensions of 200 mm×100 mm×1500 mm were cast, featuring a symmetrical reinforcement with A6 deformed longitudinal bars and A6@100 plain stirrups at different reinforcement ratios (i.e., ρ of 0.42% and ρ of 0.28%). After 28-d curing under identical conditions, the compressive strength and elastic modulus of concrete specimens were tested according to the standard GB/T 50081—2019 by a universal testing machine. A specialized support restraint device was designed and fabricated to account for both horizontal and rotational stiffness. The experimental program included three simply supported beams and seven boundary-restrained beams tested under four-point static bending. Five displacement transducers were evenly spaced along the beam span to measure deformation patterns under various load levels and record the deflection at ultimate load. Five strain gauges were installed at mid-span to monitor neutral axis variations and strain distribution under different support conditions and deflection levels. Additional strain gauges were placed at beam ends and mid-span to analyze strain variations caused under different restraint conditions. Through the quantitative analysis of experimental data, this research systematically investigated the influences of support constraint, reinforcement ratio and fiber incorporation on the membrane effects. The findings could elucidate the mechanisms by which these factors affected the ultimate load-bearing capacity of HFR-LWC beams, providing valuable insights for the structural design.

Results and discussion

Based on the experimental conditions, the test beams are grouped to investigate the influences of restraint condition, reinforcement ratio and fiber incorporation on the load-bearing capacity. The analysis of test groups under different restraint conditions reveals that the presence of tie rods significantly enhances the ultimate load-bearing capacity of the beams, and variations in both the number and position of tie rods have substantial effects on this capacity. The comparative analysis of test groups at different reinforcement ratios demonstrates that for membrane effects within a certain range of reinforcement ratios, there exists an inverse relationship between reinforcement ratio and the increase in load-bearing capacity. Specifically, a lower reinforcement ratio results in more pronounced improvements in ultimate load-bearing capacity under end restraints. The examination of test groups with and without fiber incorporation shows that fiber materials effectively participate in the crack propagation process and improve the deformation performance of the members. The analysis of strain and crack development in the test beams indicates that the mechanism by which membrane effects affect a load-bearing capacity primarily involves restricting concrete cracking and crack propagation, thereby increasing ultimate capacity, while simultaneously reducing structural deformation performance. The relationship between tie rod force and deflection shows a synchronous variation with beam load-bearing capacity. In the initial deformation stage, these two parameters exhibit the similar results. However, the tie rod force surpasses the peak load-bearing capacity of the beam, with its maximum value occurring later than that of the beam's capacity as the deflection increases.

Conclusions

Unlike conventional calculation methods that could simplify supports, the influence of end restraints on the ultimate bearing capacity of reinforced concrete members could reflects actual engineering conditions. The membrane effect increased the ultimate bearing capacity of beams by approximately 1.5 times to 5.5 times and effectively controlled the crack propagation. Compared to the influence of horizontal stiffness on the ultimate bearing capacity, the membrane effect showed a greater sensitivity to variations in rotational stiffness. The hybrid fibers could significantly improve the cracking performance of concrete, resulting in a more uniform crack distribution, which could facilitate the development of membrane effects.

Key words

membrane effect / lightweight aggregate reinforced concrete / hybrid fiber / static loading / ultimate bearing capacity

引用本文

潘建军, 陈万祥, 周新军, 彭晓丽. 基于薄膜效应的混杂纤维轻骨料混凝土梁极限承载力试验. 硅酸盐学报, 2026 , 54 (5) : 1727 -1739 . DOI: 10.14062/j.issn.0454-5648.20250410

Jianjun PAN, Wanxiang CHEN, Xinjun ZHOU, Xiaoli PENG. Ultimate Bearing Capacities of Hybrid Fiber Reinforced Lightweight Aggregate Concrete Beam with Membrane Effect[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (5) : 1727 -1739 . DOI: 10.14062/j.issn.0454-5648.20250410

基金

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国家自然科学基金(52378548)
江苏省自然科学基金(BK20221530)

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2026年第54卷第5期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250410

接收时间：2025-05-27
首发时间：2026-09-20
出版时间：2025-09-26

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出版历史

收稿日期：2025-05-27
修回日期：2025-06-17

基金

国家自然科学基金(52378548)

江苏省自然科学基金(BK20221530)

作者信息

^1．陆军工程大学爆炸冲击防灾减灾全国重点实验室，南京 210007

^2．中山大学土木工程学院，广东珠海 519082

^3．隧道工程灾变防控与智能建养全国重点实验室，广州 510275

通讯作者:

陈万祥（1977—），男，博士，副教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250410

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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